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The Big Book of Linux Ada Programming

1. 5 Building Large Projects 5 Make the Traditional Project Builder 5 1 1 A Simple Ada Makefile 5 2 Cook A Parallel Make 5 2 1 Cooking in Parallel 5 2 2 A Simple Ada Cookbook 5 3 Automake and Autoconf UNIX Portability 6 Development Utilities 6 1 Saving Time with Gnatstub 6 2 Crossreferencing with Gnatxref 6 3 Eliminating Dead Code with Gnatelim 6 4 Execution Stack amp Memory Leak Detection 6 5 Conditional Compiling with Gnatprep 6 6 Profiling with gprof 6 7 Shared Libraries Using GnatDLL 6 8 Source as Web Pages Using GnatHTML 6 9 GnatFIND file G Linux http www vaxxine com pegasoft people html book book html 3 of 10 7 20 2001 11 22 56 AM The Big Book of Linux Ada Programming 7 Optimizing Your Project 7 1 Compiler Optimization Options 7 2 Gnat Source Optimization Options 7 3 CPU Optimization Options 7 4 What Differnece Does Optimization Make 7 5 Working with the Assmebly Source 8 Debugging Your Project 8 1 Limit and the Heap Size 8 2 The Debugging Pragmas 8 3 Identifying Files 8 4 Compiler Info with gnatG 8 5 Floating Point Numbers 8 6 Gdb The GNU Debugger 8 7 Code Restrictions 9 Team Development 9 1 Change Logs 9 2 RCS Revision Control System 9 3 CVS Concurrent Versions System 9 4 Creating Transcripts with Script 9 5 Timing Execution with Time 10 An Introduction to Ada 10 1 Your Main Program 10 2
2. ESTALE f6 Stale NFS file hande EUCLEAN 7 Structure needs cleaning IENOTNAM fii8 Nota XENIX named type file ENAVAIL H9 No XENIX semaphores available EISNAM i0 Is a named type file EREMOTEIO 121 Remote I O error EDQUOT i2 Quota exceeded ENOMEDIUM 123 No medium found EMEDIUMTYPE 124 Wrong medium type Appendix A Table of Contents Appendix C gt file G Linux http www vaxxine com pegasoft people html book 99_b html 4 of 4 7 20 2001 11 39 27 AM Big Online Book of Linux Ada Programming Appendix C lt Appendix B Table of Contents Appendix D gt Appendix C Linux Kernel Calls This is a list of Linux kernel calls from section 2 of the manual exit terminate the current process llseek reposition read write file offset newselect NOS sysctl read write system parameters accept accept a connection on a socket access check user s permissions for a file door Switch process accounting on of orf adjtimex tune kernel clock afs syscall unimplemented alarm set an alarm clock for delivery of a signal bdflush start flush or tune buffer dirty flush daemon bind bind a name to a socket break unimplemented brk change data segment size cacheflush MIPS flush contents of instruction and or data cache chdir change working directory chmod change per
3. EPROTOTYPE 91 Protocol wrong type for socket EN OPROTOOPT o2 Protocol not available EPROTONOSUPPORT 93 Protocol not supported ESOCKTN OSUPPORT o4 S ocket type not supported EOPNOTSUPP 95 Operation not supported on transport endpoint EPFNOSUPPORT 96 Protocol family not supported file G Linux http www vaxxine com pegasoft people html book 99_b html 3 of 4 7 20 2001 11 39 27 AM Big Online Book of Linux Ada Programming Appendix B IEAFNOSUPPORT 7 Address family not supported by protocol IEADDRINUSE 8 Addessaleadyinuse IEADDRNOTAVAIL 9 Cannot assign requested address IENETDOWN 100 Network is down ENETUNREACH f101 Network is unreachable ENETRESET i02 Network dropped connection because of reset ECONNABORTED 103 Software caused connection abort ECONNRESET 104 Connection reset by peer ENOBUFS 105 No buffer space available EISCONN i06 Transport endpoint is already connected ENOTCONN o Transport endpoint is not connected ESHUTDOWN 108 Cannot send after transport endpoint shutdown IETOOMANYREFS 1090 Too many references cannot splice ETIMEDOUT fi10 Connection timed out IECONNREFUSED l JComec onrfued EHOSTDOWN I12 Hostisdown IEHOSTUNREACH l3 JjNomutetohot ALREADY 14 Operation already in progress EINPROGRESS l5 Operation now in progress
4. lock file MVOC Secus IECUR S Er UCE result integer myLockStruct l type F_WRLCK myLockStruct l whence 0 myboekStruct l stark 0 myLockStruct l end 0 fenti result fd E SETERW MyLOCkStruct P if result 1 then put_line standard error fcntl failed end if file is now locked unlock fille myLockStruct l type F_UNLCK myLockStruct l whence 0 fenti result fda E SELLKW Tele ess UG NT if result 1 then put line standard error fcntl failed end if file G Linux http www vaxxine com pegasoft people html book 16 html 14 of 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Double check off t size for 1 start len KB function fcntl fd file id operation F GETOWN pragma import C fcntl Get the process or process group id of owner of file The owner is the process that handles SIGIO and SIGURG signals for that file function fcntl fd file id operation gt F SETOWN arg long integer pragma import C fcntl Set the process or process group id of owner of file The owner is the process that handles SIGIO and SIGURG signals for that file This affects async files and sockets function fcntl fd file id operation F GETSIG pragma import C fcntl Get the signal number of the signal sent when input or output becomes possible on a file usually SIGIO or zero
5. Put Line chargeInterest3 is a function with an access parameter cp moneyOwing 1900 0 Put Line Charging interest on amp cp moneyOwing img if chargeInterest3 cp then Put Line After interest money owing is amp cp moneyOwing img else Put Line No interest was charged end if New Line Put Line A null pointer for an access parameter causes an exception cep null Put_Line Charging interest on a null pointer if chargeInterest3 cp then Put Line After interest money owing is amp cp moneyOwing img else Put Line No interest was charged end if New Line exception when constraint error gt Put Line Standard Error Constraint error exception raised when others gt Put Line Standard Error Unexpected exception raised file G Linux http www vaxxine com pegasoft people html book 11 html 21 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming end accparm An Example of Access Parameters chargeInterest uses an access parameter Charging interest on 1 50000E 03 After interest money owing is 1 72500E 03 chargeInterest2 uses an in out parameter Charging interest on 1 70000E 03 After interest money owing is 1 95500E 03 E chargeInterest3 is a function with an access parameter Charging interest on 1 90000E 03 After interest money
6. AFMT_S16LE 16 00000010 Little endian signed 16 bits AFMT 16 BE 168000000000 Big endian signed 16 bits AFMT S8 16 00000040 Signed bytes AFMT_U16_LE 16 00000080 Little endian U16 bits file G Linux http www vaxxine com pegasoft people html book 16 html 35 of 47 7 20 2001 11 37 16 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming AFMT_U16_BE 16 00000100 Big endian U16 bits AFMT_MPEG 16 00000200 MPEG 2 audio sndctl_dsp_setfmt constant integer newFormat integer newFormat 16 0000010 ioctlResult ioctl dsp_id sndctl_dsp_setfmt newFormat recording format now 16 bit signed little endian if newFormat 16 00000010 then Put_Line Sound card doesn t support recording format end if Selecting mono or stereo recording is a matter of 0 or 1 respectively sndctl dsp stereo constant integer 7 stereo integer stereo 1 ioctlResult ioctl dsp id sndctl dsp stereo stereo recording format now stereo if stereo 1 then Put Line Sound card doesn t support stereo end if Finally select a sampling rate sndctl dsp speed constant integer newSpeed integer newSpeed 44100 ioctlResult ioctl dsp id sndctl dsp speed newFormat recording now CD quality sampling speed if newSpeed 44100 then Put Line Sound card doesn t support samp
7. basket_6quart shipment binary shipment binary Booch components Insert t s Child gt Lef child doesn t really mai remember where NT tter because the root is root Create t add to left of BOO s number Sram y SImelonmisemiss ss pears 7 basket llquart Append t s Child Lef E After gt Left child doesn t really mat c add to right Or ae OXOJIG tter here sr number 12 s quantity bushel s contents apples Append t s Child gt Lef t After gt Right child doesn t really mat tter here out boolean is binary trees file G Linux http www vaxxine com pegasoft people html book 18 html 20 of 26 7 20 2001 11 38 18 AM Wr there s no prior item at the root Big Online Book of Linux Ada Programming 18 Data Structures Left Chita t J move t down left branch s number 3 S quantity skid s contents peaches Append t s Child gt Left After gt Right child doesn t really matter here Put_Line Our tree is Put_Line 5 6 qt baskets of cherries Put_Line 12 3 Put_Line ro 3M Ne Put_Line E Put_Line 7 11 qt baskets of pears 12 bushels of apples Put Line I Put Line Spee SSeS SSS SSS SS SSS SS SS SS SS SSS SSS s Put Line 3 skids of peaches New Line put
8. function fputc c integer fid AStdioFileID return integer pragma import C fputc fputc Part of standard C library Writes one charcter to a file function fputs s string fid AStdioFileID return integer file G Linux http www vaxxine com pegasoft people html book 16 html 25 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming pragma import C fputs fputs Writes a C string to a file function ferror fid AStdioFileID return integer pragma import C ferror Return error from last file operation if any procedure clearerr fid AStdioFileIl pragma import C clearerr Clear the error and end of file information J function feof fid AStdioFileID return integer pragma import C feof Return non zero if you are at the end of the file function fileno fid AStdioFileID return integer pragma import C fileno Return the file number for use with Linux file kernel calls function flock fd operation integer return integer pragma import C flock Locks or unlocks a file or a portion of a file This is for compatibility with other UNIXes use fcntl instead Operation LOCK SH 1 shared lock LOCK EX 2 exclusive lock LOCK NB 4 no block flag may be added to others LOCK UN 8 unlock 16 11 Stdio Pipes P
9. so there s no commenting Ed Bernal year mod 19 year 100 year rem 100 b 4 b rem 4 Selo L 7 25 l9 a t b z g 15 rem 30 eu ap e A e 4 rem 4 DUCES ren 7 easter month h u x 90 25 easter day h utx easter_month 19 rem 32 end findEaster Aa Ge TQAaNAS ll ZS 0 SS month day integer begin findEaster 2000 month day Put Easter Sunday 2000 is month amp month img file G Linux http www vaxxine com pegasoft people html book 12 html 20 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages Put Line and day amp day img end easter Easter Sunday 2000 is month 4 and day 23 12 7 Tags Package Ada Tags contains some utility procedures to for the invisible tags that accompany tagged records including converting tags to and from strings The following program shows what the tags package can do and shows tag comparison with the in operator with text io ada tags procedure t is type ParentRec is tagged record i 8 integer end record type ChildRec is new ParentRec with record J integer end record child ChildRec begin Text IO Put Line Working with Tagged Record Tags Text IO New Line Text IO Put Line ParentRec has an expanded name of amp Ada Tags Expanded Name ParentRec Tag Text IO Put Line ChildRec has an expanded name of amp Ada Tags E
10. Appendices file G Linux http www vaxxine com pegasoft people html book book html 9 of 10 7 20 2001 11 22 56 AM The Big Book of Linux Ada Programming Appendix A The Linux Shell Appendix B Linux Error Codes Appendix C Linux Kernel Calls Appendix D Signals Appendix E Ioctl parameters Appendix F Overview of Gnat Packages Glossary file G Linux http www vaxxine com pegasoft people html book book html 10 of 10 7 20 2001 11 22 56 AM The Big Book of Linux Ada Programming i Preface I ve been working with Linux since kernel 0 97 and with Gnat since version 2 00 In the past five years or so I ve been frustrated by the lack of documentation on Linux Ada programming Gnat is one of the most powerful development environments for Linux certainly superior to C or C and yet most people have never heard of it Those that have often ignore it because they can t find enough documentation to install Gnat let alone to evaluate it After my article Gnat C and Java under Fire published in the October 1998 edition of Linux Journal I decided to collect my knowledge of Linux Ada programming and set down what I ve learned from installing Gnat to interfacing with the Linux kernel I wanted to create a book that had everything I needed in one place to write professional Linux applications After publishers declined to put it in print because Ada developers are a small though growing niche in the Linux mark
11. H8i NES gumakc guto e H8igd NES pumakc gE o H8 No mamake o os No gamac 0 os Hi3 No pmake 02 oss H736 No Although the proper optimization can make this program run faster but with overflow checking was turned on with gnato the overflow error is caught The lesson here is that error checking only works when it s turned on We can compare the results to the equivalent C program int p int param return param 4 file G Linux http www vaxxine com pegasoft people html book 7 html 6 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Programming 7 Optimizing Your Project int i int j 2147483647 int all oO int main for i l i lt 100000000 i j abs a 5 al j 10 3 10 return 0 GCC Switches Pragmas CPU Time Size Error Caught gcc Wall gB 8s 24541 No gce O3 Pent 8 6s 24541 No In this case notice that C never detected the overflow error Secondly notice that the Ada program ran twice as fast as the C program In theory an Ada compiler can take advantage of the typing information and the optimization hints provided by the pragmas The C compiler has less information and this can hinders the optimization process I ve never investigated whether or not Gnat does this or how much of an effect it has The optimization techniques will affect different programs differently
12. import a non Ada function with additional information over pragma Import import Object import a non Ada object with additional information over pragma Import import a non Ada procedure with additional information over pragma Import Procedure Import nem studs OCDE import a non Ada side effect function with additional information over port pragma Import Inline the indicated subprogram may be inlined Inline_Always forces inter unit inlining regardless of compiler switches Inline_Generic for compatibility with other Ada compilers fnspection Point a sunbe setts given point inthe program for code validation Interface Name for compatibility with other Ada compilers Interrupt Handler declare a signal handler procedure Interrupt Priority Specify the task protected object s priority where blocking occurs Linker_Alias select an alternative linker for a package or other linkable unit Linker_Options pass a string of options to the linker Linker_Section the gcc linker section to use Lit ist source code while being compiled Locking_Policy Spcify how protected objects are locked and when blocking occurs Machine_Attribute specify GCC machine attributes No Rem specify a procedure that is deliberately never returned from to avoid B compiler warnings No Runtime ensures no gnat run time routines are use e g for creat
13. Ada subprograms can have the same name as long as their parameters or return values are different This is called overloading If Ada can t determine which subprogram you are referring to you ll receive an error when compiling In the above example is overloaded since there s integer addition floating addition and the other built in file G Linux http www vaxxine com pegasoft people html book 10 html 26 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada meanings for and our special salary addition we just defined C Assignment is not an operator in Ada Assignment overloading can be simulated with controlled tagged records and the Adjust procedure 10 11 Control of Flow for linterativeloop fo Whie Pretestloop o o e ei opat oo o wk The if statement is well a standard if statement which you can find in many languages Here s an example if x gt 0 then Text_IO Put_Line X is positive elsif x lt 0 then mm Text_IO_Put_Line X is negative else Text IO Put Line X is zero end if Ada provides two expression short circuiting operators or else and and then Short circuiting means that the expression will not be evaluated if the left side doesn t satisfy the condition if x gt 0 or else y gt 0 then In this case y gt 0 is only checked if x is not greater than zero There is a general purpose loop s
14. Big Online Book of Linux Ada Programming Appendix E 0x00005384 SCSI TOCTL TAGGED DISABLE void 0x00005385 SCSI IOCTL PROBE HOST const int MORE imclude linux smb fs h 0sx90027501 SMB IOC GETMQUNTUID uxz t M lt inelude linux sockics h gt 0x0000890B 0x0000890C 0x00008910 0x00008911 0x00008912 0x00008913 0x00008914 0x00008915 0x00008916 0x00008917 0x00008918 0x00008919 0x0000891A 0x0000891B OxOOUOSSTC 0x0000891D 0x0000891E 0x0000891F 0x00008920 0x00008921 0x00008922 0x00008923 0x00008924 OxOOGDOSS2S 0x00008926 0x00008927 0x000089279 0x00008930 0x00008931 0x00008932 0x00008940 0x00008941 0x00008950 0x00008951 0x00008952 0x00008960 0x00008961 S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S OCADDRT const struct rtentry MORE OCDEBRI const struct rrenircy MORE OCGIFNAME char OCSIFLINK void TOCGIFCONE struct 1fcont MORE IOCGIFFLAGS struct ifreq I O IOCSIFFLAGS const struct ifreq IOCGIFADDR struct ifreq I O IOCSIFADDR const struct ifreq IOCGIFDSTADDR struct ifreq I O IOCSIPDSTADDE Const struct irreg lt OCGIFBRDADDR struct ifreq I O OCSIFBRDADDR const Struct ifregq OCGIFNETMASK struct ifreq I O OCSIFNETMASK const Struct ifreq LOCGIPMETRIC struct r1ifreq I O TOCSIEMETRIC Comst Struct ifreq IOCGIFMEM struct ifreq I O IFMEM const struct ifreq IFMIU struct
15. Gre iGt new Memory NW W Pp Gre lene N O0 W PY float write Str F float read Str G Eree Str put_line end Main IEA TBE LoS Demonstration has begun 23 Demonstration has begun Buffer_Stream 4096 cural image T A teger image T amp float image T 2 cural image U A teger image U amp float image U 2 CESCE amp float image G Demonstration complete A Stream Nive An initialized record For lst read For 2nd read An initialized float For 3rd read Create in memory buffer stream 4096 Write record R to stream Read stream back to record T Dump out T Rewind the read pointer Now read into record U Dump out U Implies a read rewind also Write F to stream Read stream into G Report G for verification Delete stream file G Linux http www vaxxine com pegasoft people html book 11 html 34 of 39 7 20 2001 11 33 47 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming slags 1 41400E 00 25 O5 toink 1 41400E 00 fe DOOR On Demonstration complete NNW PN ll ie wen 11 13 Pragmas Pragmas sometimes called compiler directives are statements that provide additional information to the compiler build a better executable Pragmas never change the meaning of a program The fol
16. then Put_Line We are at the end of the file else Put_Line We aren t at the end of the file end if New_Line Pat_line Closing file J Close CustomerFile end sequentio Ni This is a Ada Sequential_IO example We created the file home ken ada trials customer seq We re currently using OUT_FILE The file is open mode Writing Tokyo Book Distributors Writing General Pizza Inc End_of_File not allowed on Out files file G Linux http www vaxxine com pegasoft people html book 12 html 10 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages End of File caused Ada IO Exceptions Mode Error Reset can change the file mod Changing to In File mode Reading the next customer Read Tokyo Book Distributors Reading the next customer Read General Pizza Inc End of File works on In files We are at the end of the file Closing file Form not covered KB 12 4 Direct IO In relational database programming you create tables of information The tables act like arrays that are limited in length by the amount of disk space you have Each table consists of a series of rows and each row is divided up into subcategories called columns A telephone book for example can be considered one large table Each row contains information about a different person Each row is subdivided into columns of names addresses and pho
17. use formatted_io procedure ShowValues s string is begin put 0 0 and amp s amp gt pu uc 0 0 To Este s new_line put T 75 12 and T s amp T gt 1 put 15 12 To Picture ey jy J new_line put T75 12 and Ves E gt Ty begin put 79 12 To Picture 2 J exception when others gt put LAYOUT BISOUS end new_line end ShowValues begin put_line This is an example of Formatted Output put_line my put line Default currency symbol is amp Default Currency put line Default fill character is amp Default Fill amp put line Default separator character is amp Default Separator amp put line Default radix mark is amp Default Radix Mark amp new line mew SOOO MEO M New Line Showvalues A4AA9299 s New Line Slaw Avenue M ew usw y I ue um New Line ShowValues 9 99 file G Linux http www vaxxine com pegasoft people html book 12 html 16 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages New_Line ShowValues 9 99 New Line ShowValues lt 9 99 gt New Line end formatted This is an example of Formatted Output Default currency symbol is Default fill character is Default separator character is Default radix mark is
18. Big Online Book of Linux Ada Programming 18 Data Structures e Preserve inverse of Purge keep consecutive items removing the rest Share _Head _Foot make the list an alias for a sublist in another list Tail discard everything but the last item in the list Length return the number of items in the list Is_Null true if the list has no items Is_Shared true if there an alias to a sublist in the list Head return the top most item Foot return the last item in the list Item_at return an item at a given position New Iterator return an iterator for traversing the list Process Head Tail generic procedure to return an item with processing Swap Tail NQS KB Notice that the term Foot refers to the last item in the list The Ada string packages uses the term Tail Here s an example with BC Containers Lists Single with Global Heap package customers is type aCustomer is record customerID integer accountBalance float end record his is the item to put in the list package customerContainers is new BC Containers Item gt aCustomer create a new controlled tagged record container for customers package customerLists is new customerContainers Lists create a new list support package for our using container type package customerList is new customerLists Single Storage Manager gt Global Heap Pool Storage Global Heap Storage create a single linked list package usin
19. EYPS nev pasen per Wt Extend an object class 2 parenttype record type access all sometype Define a pointer to a class sometype file G Linux http www vaxxine com pegasoft people html book 11 html b of 39 7 20 2001 11 33 44 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming class Class wide type vier wel abstract Abstract types subprograms function 0 C Ada developed its own object oriented terminology because C s terminology can be ambiguous and confusing Ada differentiates between a class and the structure that defines that class An object in Ada is known as a tagged record That is it is a normal Ada record that has an invisible tag attached to it The record type anEmployeeProfile is record name string 1 80 age anAge end record can be changed to a tagged record by adding the keyword tagged type anEmployeeProfile is tagged record name String 1 380 age ys ome end record Although these two records look the same if we use the size attribute to see how much memory the records take up we ll see that the tagged record is bigger The extra space is used to store the invisible tag Unlike normal records fields can be added tagged record and a new tagged record can be created This is called extending the record To create a related record with additional fields we use the keyword new type anHourlyEmployee is new anEmployeeProfile with re
20. Global Heap Storage create a dynamic collection holding products end products with ada text io BC products use ada text io BC products procedure collection demo is products produce Col lectson Dynamic Collection p gt aProduct 3 productContainers Iterator class productCollection New Iterator file G Linux http www vaxxine com pegasoft people html book 18 html 13 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures products begin Put Line This is a demo of the Booch components collections New Line products productCollection Create 100 The Newly Declared Collection Put Line The collection is newly declared with a chunk size of 100 Put Line The collection is empty amp productCollection Is Empty products img Put Line The collection length is amp productCollection Length products img Put Line The collection chunk size is amp productCollection Chunk Size products img New Line Adding an Item joo Ol B te SOs p weight 17 0 producrCol lection Append products P P t Line product idi e p idtimg amp was added Put_Line The collection is empty amp productCollection Is Empty products img Put Line The collection length is amp productCollection Length products img Put Line The
21. PEOL TpError y perror is a standar the last error mess standard C librarie eds aFilerD playinfo cdrom ti dummy ADummyParam ioctl_result integer close_result integer chs character begin da eMibrary elsubib ice prine az age from a kernel call or the s on the screen Put_Line thats program plays an audio CD 1n your New_Line open the dev cdrom ibishakiaie ocell Put_Line Openning Open cd DevCDROM 0 if cd 0 then file so we can control the amp IBS CDROMs Js Uses Uh qur VF perror Error openning CDROM drive end if start the CDROM drive Put_Line Spinning up Cheon gow JP TD DROM drive DROM drive ioctl noparam ioctl result cd CDROMSTART dummy if ioctl resul 0 then perror Error sp end if display menu New Line PGhe Toa C Wil s eM bero 2 New Line inning up the CDROM drive Qui y Jm file G Linux http www vaxxine com pegasoft people html book 13 html 10 of 15 7 20 2001 11 35 52 AM s Big Online Book of Linux Ada Programming 13 Linux Introduction Main loop Repeat until 2 is selected loop Pit Select a function 1 2 1 J Get ch case ch is when 1 gt playinfo start_track 1 playinfo start_index playinfo end_tra
22. The System Machine_Code package can embed assembly language instructions in an Ada program Since Gnat is based on file G Linux http www vaxxine com pegasoft people html book 11 html 38 of 39 7 20 2001 11 33 48 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Gcc it uses Gcc s inlining features If you ve inlined assembly code in a C program you ll find Gnat s capabilities virtually identical Assembly code is embedded using the Asm Asm nop do nothing A tutorial by Jerry van Dijk is available from AdaPower com Large sections of assembly code should be linked in separately lt Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 11 html 39 of 39 7 20 2001 11 33 48 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages 12 Standard Gnat Packages lt Last Chapter Table of Contents Next Chapter gt This section summarizes some of the more than 100 packages that come with the Gnat compiler These include string handling operating system binding and sorts 12 1 Standard String and Character Packages Ada Package Descrip on C Equivalent Ada Character Handling Character operations Stringsh Ada Strings Fixed Adastingopertios Stingsh Ada Strings Bounded Bounded strings and operations Ada Strings Unbounded
23. e No O fastest compiling but gives you gnat warnings for optimization pragmas Use only when fast compiling is essential e O O1 slower compiling cleaner executable and no pragma optimize warnings from gnat You should normally include this e O2 more optimization Use this for the smallest executable e O3 full optimization automatic code inlining for small subprograms and loop unraveling Use this for the fastest executable When using floating point numbers you may experience rounding errors if you don t use the ffloat store switch as discussed in 8 5 Inlining is also affected by two other switches e gnatn allow inlining between packages where pragma inline is used in a package specifications e gnatN allow automatic inlining between packages this is very memory intensive e No gnatn N no inlining between packages even if a pragma inline is used in a package file G Linux http www vaxxine com pegasoft people html book 7 html 1 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Programming 7 Optimizing Your Project specification These switches both require a O switch for inlining to take effect The gnatp switch turns off all non essential error checking such as constraint and range checks This is the same as using pragma Suppress All Checks on every file in the entire program making the program smaller and faster There are some other gcc optimization switches which can somet
24. nandi risb 1 leomet gdb info locals SOI SSS awinfo vAppWinInfo 8x8 appname 8x48133e Hy V App gdb ii CAvivide testvide myapp cpp UserDebugi Build mu amp pp New pplulin Xs Xn appname ff Create the first window using provided CmdWindow if my 0 zmgCmd in new mgCmdUindou appname u h if Clawinfo awinfo new vAppWinInfolappnaome return vApp NewAppWin _myCmdWin appname w h awinfo VIDE 38 26 Command 3 3 5 GLIDE 3 3 6 file G Linux http www vaxxine com pegasoft people html book 3 html 10 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 4 From Source Code to Executable 4 From Source Code to Executable lt Last Chapter Table of Contents Next Chapter gt This section is an overview of creating new programs on Linux 4 1 Gnat Filename Conventions Unlike Microsoft Windows Linux filenames do not require a suffix to indicate the filetype Nevertheless Linux files often have suffixes to make it easier to identify the type of files by their names gnat makes extensive use of suffixes Here are some filename conventions e ads Ada package specification adb Ada package body or program adc Gnat configuration file for dead code elimination adt Gnat tree file for dead code elimination adj Defaults for NQS KB adp TIA project file or Gnat gnatxref gnatfind project file
25. Alt Char Jump to the item with hot key Char Linux Console xterm Scroll Bars Keys file G Linux http www vaxxine com pegasoft people html book 3 html 2 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s Down Arrow 10 Forward in Document End Bottom of Document Home Top of Document Left Arrow Back one line Right Arrow Forward one line Up Arrow 10 Back in Document In TIA the width of the text is limited to size of the edit area Any lines that are longer that the edit area are denoted with an ellipsis at the end The edit area does not scroll left or right as it does in pico 3 1 3 The File Menu New Source Start a new source file Open Source Open a new source code window or an existing one Type in the name of the source file and choose open to open it adb is assumed if you don t specify an ending Choose browse to walk through the directories using a open dialog box Or you can chose one of the recently opened files that appear at the bottom On the Linux console use alt to open these files Chose new and TIA will create an empty package body for you to fill in just delete what you don t want Save Saves the file TIA automatically saves whenever you check or build Save As Save As Save the file under a different name Revert Reloads the current file discarding any changes that haven t been saved by you or TIA TIA automatically saves a file
26. Buf Buffer Last then raise Ada IO Exceptions End Error end if Buf Buffer Buf Write Offset Last Item ISRbITE 5 eate ORE TES EIE m BUE Vie EIE e OE ETE SIE a COUNT end Write procedure Read Buf in out Memory Buffer Item out Stream Element Array Last out Stream Element Offset is Xfer Count tream Element Offset Item Last 1 Item First Data Count Stream Element Offset Buf Write Offset Buf Read Offset begin E ep if Xfer Count gt Data Count then Xfer Count Data Count end if Item 1 Xfer Count file G Linux http www vaxxine com pegasoft people html book 11 html 32 of 39 7 20 2001 11 33 47 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Buda Sue EE leute o RScicmOr IE S IE a BRUE Read OffESetEtxfer Count 1 Buf Read Offset Buf Read Offset Xfer Count Last Item First Xfer Count 1 end Read Rewind the Read offset in the Memory Buffer procedure Rewind Read Buf in out Memory Buffer is begin Buf Read Offset Buf Buffer First end Rewind Read Rewind the Write offset in the Memory Buffer procedure Rewind Write Bu
27. F RDLCK constant aLock 0 read lock F WRLCK constant aLock 1 write lock F UNLCK constant aLock 2 unlock remove a lock F EXLCK constant aLock 3 exclusive lock F SHLCK constant aLock 4 shared lock type aWhenceMode is new short integer SEEK SET constant aWhenceMode 0 absolute position SEEK CUR constant aWhenceMode 1 offset from current position SEEK END constant aWhenceMode 2 offset from end of file type lockstruct is record l type aLock type or lock l_whence short_integer how to interpret l_start l start integer OBESE or position l len integer number of bytes to lock 0 for all l pid integer with GETLK process ID owning lock ense To lock a file create a lockstruct record and fill in the details about the kind of lock you want A read lock F RDLCK makes the part of the file you specify read only No one can write to that part of the file A write lock prevents any other program from reading or writing to the part of the file you specify Your program may change that part of the file without being concerned that another process will try to read it before you re finished If your program stops prematurely the locks will be released Example Get exclusive right to write to the file waiting until it s possible
28. G Linux http www vaxxine com pegasoft people html book 99 html 3 of 3 7 20 2001 11 39 10 AM Big Online Book of Linux Ada Programming Appendix B lt Appendix A Table of Contents Appendix C gt Appendix B Linux Error Codes Linux numeric error codes as defined by the Linux kernel EPERM Operation not permitted ENOENT R Neswhfleordmeory S S ESRCH B Nosuchprocess ENIR H Jmemupedsysemcal SOS EO Wemr ENXO 6 Woswhdevieoraddes EBG 7 hsobg O ENOEXEC Excfomacmr o EBADE 89 Ba iemumbr ECHLD fo Nochidpcess EAGAN i yamn ENOMEM 2 Owofmemzy EACCES 3 Permission denied EFAULT i4 Baddes SS ENOTBLK 5 Block device required EBUSY i Deveormsucebuy EEXIST o Fhess EXDEV 8 Gesdekelink ENODEV o Noschdwke ENOIDR o Nead moy EID Di sadmcoy EINVAL 2 mvdagammt ENHLE 3 Fi beoviw EMHLE 4 froomanyopenfiles ENOTIY ps5 Nea ydwie ETXTBSY pe Hexfiebuy file G Linux http www vaxxine com pegasoft people html book 99_b html 1 of 4 7 20 2001 11 39 27 AM Big Online Book of Linux Ada Programming Appendix B EBG 7 Filetoolage SCS lt S S S ENOSPC ps Nospcekfondwie Esme po Wieglsck SSCS EROFS bo Redonflesstem SSOSOSC S S
29. Title YAK Bulletin Board System for Linux Version 1 08b Entered date 09JUN97 Description BBS software with sources for DOS OS 2 and Linux Includes also tosser and tick program without sources Keywords yak bbs tosser conference bulletin board Author skyreader fw nullnet fi Timo Sirainen Primary site Skyliner BBS 358 15 176242 Alternative site sunsite unc edu Platform DOS OS 2 Linux Copying policy GPL End Here is the LSM entry for System Manager in a Box 0 9 1 beta Begin3 Title System Manager in a Box Version 0 9 1 beta Entered date Wednesday May 26 1999 Description Linux configuration and administration utility using AI techniques PegaSoft home page is http www vaxxine com pegasoft Keywords system administration box ai pegasoft file G Linux http www vaxxine com pegasoft people html book 20 html 5 of 7 7 20 2001 11 38 49 AM Big Online Book of Linux Ada Programming 20 Developing Your Project Author pegasoft tiamet vaxxine com PegaSoft Canada Maintained by pegasoft tiamet vaxxine com PegaSoft Canada Primary site metalab unc edu pub Linux system admin 700kB smiab 0 9 1 tgz Alternate site Original site Platforms Copying policy freeware End KB platform or platforms Details about the format are available from the LSM web site To register a program with the Linux Software Map email your LSM entry to lsm execpc com with the subject add 20
30. Unbounded strings and operations Ada Strings Unbounded Text IO Text JO for Unbounded Strings Ada s built in strings or fixed strings are made of array of characters The length of the array determines the bounds of the string A string that s too short for an array is padded with blanks Although these strings are fast they are cumbersome to use and not practical for string intensive applications One problems is although the string type is an array with an undefined upper bound sooner or later you have to specify an upper bound and run the risk of constraint errors working with arrays of different sizes Ada operator amp concatenates fixed strings this is the only built in operator for fixed strings There are two alternative strings in Ada Bounded strings are arrays of strings with a definite maximum size separate from the length which eliminates to constraint errors These strings are still relatively fast but waste a lot of storage on small strings and you run the risk of overflowing the string I use 255 character bounded strings as general purpose strings in my programs The standard Ada library Ada Strings Bounded contains the definition of bounded strings and similar operations to Ada Strings Fixed Because bounded strings have a definite upper bound the package is generic and has to be instantiated for the maximum length The library also includes a function to convert a bounded stri
31. Work schedules not including small retail stores often affected by these holidays e New Year s Day January 1st Birthday of Martin Luther King U S third Monday in January Inauguration Day U S January 20th every four years starting in 1937 Washington s Birthday U S third Monday in Febrauary Inauguration Day U S March 4th every four years pre 1937 Good Friday and Easter Sunday see below Armed Forces Day U S third Saturday in May Memorial Day U S last Monday in May Flag Day U S June 14th Canada Day Canada July 1 United States of America s Independence Day U S July 4 Labor Day first Monday in September Columbus Day second Monday in October Thanksgiving Day Canada second Monday in October Election Day U S Tuesday on or after November 2 Veterans Day U S November 11th Remembrance Day Canada November 11th Thanksgiving Day U S fourth Thursday in November Christmas Day December 25th North American Banking and postal Holidays include Easter Monday and Victoria Day Canada Daylight Savings Time Daylight Savings time begins first Sunday in April but not in Arizona Hawaii and parts of southern Indiana Daylight Savings Time ends last Sunday in October but not in Arizona Hawaii and parts of southern Indiana Table Other Widely Celebrated North American Observances e Groundhog Day February 2 Lincoln s Birthday U S February 12 Valentine
32. cfg GLADE distributed program configuration file ali debugging and linking information produced by gnat xrb cross reference file generated by gnatf GRASP defaults GRASP defaults file holds your preferences gpj a grasp project file gui a VAD TCL TK widget description For example demo adb would be an Ada program named demo You can change the colour used by 1s to display these filenames by changing the etc DIR_COLORS file Directions on how to do this are included in the file 4 2 Writing Your First Ada Program file G Linux http www vaxxine com pegasoft people html book 4 html 1 of 8 7 20 2001 11 31 15 AM Big Online Book of Linux Ada Programming 4 From Source Code to Executable 4 2 1 Writing a program with an IDE Start a new project For example with TIA type tia hello to create a new project called hello adp Type in the following Ada program with text_io use text_io procedure hello is begin put line Hello World end hello This Ada program will print a short message on the screen Save the file and build the project If there is a problem with your program TIA will show you the line number the position on the line and an error message describing the problem If you typed in the program correctly you should now have an executable file called hello in your directory TIA will ask you if you want to run your program Your program should display the message Hello Wo
33. def beep def base file beep base output exp beep exp output lib libbeep a gnatbind n beep ali gnatlink beep ali beep exp o beep dll mdll This is a def file I am using beep def EXPORTS DlIIGetClassObject DlIGetClassObject 12 22 DIICanUnloadNow DllCanUnloadNow 0 3 DIIRegisterServer DlIRegisterServer 2 024 DIIUnregisterServer DllUnregisterServer 2 0 2 5 NOTE Since the exported functions or STDCALL I need to provide the number of bytes used for parameters If you were using standard pragma C stuff it would be MYFunction 9 XXXX where XXXX is what ordinal in the DLL BTW you can leave this out all together if you don t need it and just put the name of the function on the line end Gnat has an option called static which will link all shared libraries into your executable as if they were static libraries This makes your executable completely self contained but may violate GPL licensing restrictions on certain libraries Gnat comes with one shared library libgnat a If you link a gnat program without the static option you have to copy this file into a standard library directory e g lib and run ldconfig so that Linux will be able to find the gnat library when executing your programs Gnat always automatically links in the library you never have to type lgnat explicitly when linking file G Linux http www vaxxine com pegasoft people html book 13 html 14 of 15 7 20 2001 11 35 52 AM Big Online Book
34. end case C case is like switch but the cases don t fall through Cases can also use ranges such as 1 10 or TaxSubtype range I really like goto s and through a stroke of good luck Ada includes a goto Goto labels are denoted with double angle brackets unlike loop labels that use a colon for I in 0 10 loop some computations here if emergency then goto Help end if end loop stuff that must not be executed in an emergency Help Text IO Put Line We are now down here Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 10 html 29 of 29 7 20 2001 11 33 08 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming 11 Advanced Ada Programming lt Last Chapter Table of Contents Next Chapter gt 11 1 Packages Ada Description C Equivalent package Define a package C In C classes serve two purposes First they hide declarations Second they implement objects In Ada declaration hiding is done separately with packages you do not need to use tagged records to use packages Large Ada programs are divided up into packages These are collections of procedures functions variables and other declarations that serve a similar purpose You can have packages to draw text on the screen or packages to do accounts payable or package to work with complex numbers To make it easier for different pe
35. freeze intptrs begin int pointer five unchecked access int address five address int pointer intptrs to pointer int address file G Linux http www vaxxine com pegasoft people html book 8 html 4 of 6 7 20 2001 11 32 24 AM Big Online Book of Linux Ada Programming 8 Debugging Your Project int address intptrs to address int pointer 1S e XE DUE IUE end pointers 8 5 Floating Point Numbers The GCC FAQ reports that floating point rounding problems can occur with O2 and O3 unless you use ffloat store keeps floating point numbers out of CPU registers Using this switch will slow your program 8 6 Gdb the GNU debugger gnat 3 11 and later with a version of Gdb the GNU command line debugger that fully supports Ada data structures You shouldn t have to use Gdb very often as most problems are solvable with a few well placed put line s However if the program produces are core file or is behaving unpredictably because of an obscure coding mistake or a compiler bug Gdb is the best way to find out what is going wrong and where In order to use Gdb you must compile your program with debugging support enabled with the g option in gnat or ggdb in C To start Gdb on a program called dbase use gdb dbase or gnatgdb with the ALT version and Gdb responds with its command line prompt gdb Type run to start the program normally to the point of the crash You can print out the value of variables using t
36. gee p S oss How t0 Compile andivyiaual OC files a gust in caseo We want to mie C and Ada Toce soe qeu e ae How to bind and link the main program Mein DOBJS 4 gaatpind xe maim ala Gnatlink Mmain ali How to clean up intermediate files elean e im 4 8 1 core There are many other features in cook not covered here More information about cook can be found in the Cook User Manual and the Cook Reference Manual file G Linux http www vaxxine com pegasoft people html book 5 html 4 of 6 7 20 2001 11 31 40 AM Big Online Book of Linux Ada Programming 5 Building Large Projects 5 3 Automake and Autoconf UNIX Portability If you want to create projects that run on a variety of UNIX platforms not just Linux you ll want to look at GNU autoconf and automake The GNU tools use these programs extensively Included with Linux autoconf creates a shell script called configure Customized for your project when this script is executed it scans the features of the particular UNIX that it is running on and tailors all Makefiles accordingly It optionally produces a C file called config h which contains information about the features it found automake the other half of autoconf creates a Makefile in using templates called Makefile am Once automake is finished all you have to do is run configure to make your final makefile and type make to build the project on
37. gt convention DisplayCurrency fieldWidth gt 8 useDollarSign gt false c gt 1 97 You can also declare arbitrary blocks in Ada These let you declare variables in the middle of a procedure or function or set apart the designated source code in it s own block The form of a block is an optional declare section and the block denoted by a begin and end procedure nested is Date integer begin Date 0 declare DaysInYear constant integer 365 begin patem DateS webs ntes end end nested Here DaysInYear only exists for the assignment statement that follows it The main reason for blocks is to add an exception hander to a particular line without having to write a one line procedure begin Total Total Average exception when numeric error gt Text IO Put Line Division by zero Total 0 end Here if there s a numeric error during the division statement it s caught and handled Operators are in fix functions ones that take parameters on their left and right For example is an operator Ada lets you redefine most of the standard operators so they work with types of your choosing You enclose the operators symbol in double quotes function e employeeRecord s aSalary returns aSalary is begin return e salary sS end function The above function will let you add a salary to an employee record which assumes you are referring to the salary field in the employee record
38. output to a file name file O list objects p pessimistic try worst case elaboration order r renames the main program from main to gnat main s require all source files to be present shared link in Gnat run time library as a shared library if available for example ALT version static link in Gnat run time library statically t ignore time stamp errors Tn tasking time slices are n milliseconds long n 0 means no time slicing as per Annex D We treat warnings as errors file G Linux http www vaxxine com pegasoft people html book 4 html 6 of 8 7 20 2001 11 31 15 AM Big Online Book of Linux Ada Programming 4 From Source Code to Executable ws suppress all binder warnings e v verbose messages e x check only ignore source files Don t generate a binder program See s e z same as n KB 4 6 Gnat Linking Options gnatlink combines object files together to form a finished executable program You can run it by itself or gnatmake can run it for you e o file name of executable file to create e v verbose messages e gnatlink n instead of gcc use linker named n e llib in the specified library When linking in libraries the order of the libraries is important When libraries depend on each other libraries must be listed before the libraries that they use 4 7 Gnatmake Options To compile any Ada program use the gnatmake command gnatmake checks all the packages a progra
39. procedure K exit pragma import C K exit exit pragma import valued procedure K exit exit is a kernel call to stop your program It leaves any open file open Not recommended in an Ada program there are more effective ways to stop your program Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 16 html 47 of 47 7 20 2001 11 37 18 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada 17 Moving C Programs To Ada lt Last Chapter Table of Contents Next Chapter gt 17 1 c2ada Translating Your Programs c2ada is available from http www skinner demon co uk aidan programming 17 2 Interfaces C package int Cinteger fint etc The Interfaces C and Interfaces C Extensions packages provide basic type definitions and conversions functions for C programs Gnat 3 12 introduces a new boolean type C_bool which behaves as a proper C boolean value 0 is false and any other value is true One thing to remember about this package is that C strings are defined as an array of characters and Ada will raise a CONSTRANT_ERROR exception if two arrays of characters are not exactly equal length even if a smaller array is being assigned to a larger one For example s ehar array b sS mE ome Mice nasa Ecl This example will raise the exception because the string is 11 characters long 10
40. procedure bind result out int sockfd aSocketFD Sa in out aSocketAddr addrlen int pragma import C bind pragma import valued procedure bind give socket a name 0 if successful procedure Connect result out int socket aSocketFD Sa in out aSocketAddr addrlen int pragma import C connect pragma import valued procedure connect connect to a Internet server 0 3f successful procedure Close fd aSocketFD pragma import C close close the socket discard the integer result procedure Read result out integer from aSocketFD buffer in out string buffersize integer pragma import C read pragma import valued procedure read read from a socket procedure Write result out integer from aSocketFD buffer system address buffersize integer pragma import C write file G Linux http www vaxxine com pegasoft people html book 16 html 40 of 47 7 20 2001 11 37 17 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming pragma import_valued_procedure write write to a socket package addrListPtrs is new System Address To Access Conversions System Address We need to use C pointers with the address list because this is a pointer to a pointer in C This will allow us to dereference the C pointers in Ada subtype addrListPtr is Syste
41. return end if New Line Lookup the IP number for the server Put Line Looking for information on amp ServerName Put Line GetHostByName amp ServerName amp myServer GetHostByName ServerName amp ASCII NUL myServerPtr HEptrs To Pointer myServer if myServerPtr null then P t_Line Standard_Error Error looking p Se eT return end if Put_Line IP number is amp myServerPtr h_length img amp bytes long addrList addrlistPtrs To_Pointer myServerPtr h_addr_list New_Line Create the IP port and protocol information Put_Line Preparing connection destination information myAddress family AF INET myAddress port htons 80 memcpy myAddress ip address addrlist all myServerPtr h length New Line Open a connection to the server Put Line Connect Result Socket Family Address rec F A rec size file G Linux http www vaxxine com pegasoft people html book 16 html 43 of 47 7 20 2001 11 37 17 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Connect Result mySocket myAddress myAddress size 8 put Gonnece Me Result amg amp 171 Put myAddress family img amp PutIPNum myAddress ip Put amp integer image myAddress size 8 amp if Result 0 then perror Error connecting to serv
42. 1 1 A Brief History of Linux 1 2 1995 The Year of Ada and Gnat 1 3 Why use Ada 1 4 Why Ada and Linux 1 5 Linux Ada Resources 2 Installing Gnat on Linux 2 1 Installing the ALT RPMs 2 2 Installing the ACT Binaries 2 3 Compiling Gnat from its Sources 2 4 Case Study Installing Gnat 3 11 on over an old Linux Distribution 3 The Integrated Development Environments 3 1 TIA The Console IDE 3 1 1 Quick Start 3 1 2 TIA Keyboard Legend 3 1 3 The File Menu 3 1 4 The Edit Menu 3 1 5 The Find Menu 3 1 6 The Misc Menu 3 1 7 The Project Menu 3 1 8 The Menu 3 2 GRASP the X windows IDE 3 2 1 Installation 3 2 2 QuickStart 3 2 3 The Project Window 3 2 4 The Source File Window 3 2 5 The Button Bar 3 3 Other Tools and IDEs 3 3 1 VAD 3 3 2 Jessie 3 3 3 RAPID 3 3 3 VIDE 3 3 5 GLIDE file G Linux http www vaxxine com pegasoft people html book book html 2 of 10 7 20 2001 11 22 56 AM The Big Book of Linux Ada Programming 4 From Source Code to Executable 4 1 Gnat Filename Conventions 4 2 Writing Your First Ada Program 4 2 1 Writing a Program with an IDE 4 2 2 Writing a Program without an IDE 4 2 3 After Building 4 3 The Three Step Process 4 4 Gnat Compiling Options 4 4 Run time Error Checking 4 4 2 Checking without Compiling 4 4 3 When you have Too Many Errors 4 5 Gnat Binding Options 4 6 Gnat Linking Options 4 7 Gnatmake Options 4 7 1 So you changed the comments
43. 10 7 2 Text IO and New Types To perform Text IO input and output on new types you have to create your own version of Text IO for the new type This process is called instantiation and is covered later in the section on generics The format is package MyNewTextlOPackage isnew PredefinedGenericlOPackage mytype For example to create a Text IO package for the aSalary type package aSalary Text IO is new Ada Text IO Float IO aSalary Ada creates a new package called aSalaray Text IO customized for the aSalary type You can use your package just like one of the standard Ada numeric Text IO packages Salary NI OR OT SE DO aSalary Text IO Put Salary The following table lists all the Text IO packages that can be instantiated for a particular type Table Predefined generic Text IO packages for performing Input Output Base Type Package Decimas NQ Ada Text 10 Decimal T0 10 8 Aggregate Types Arrays are tables of values with specific bounds For example to declare a table of 10 people type peopleHeightList is array 1 10 of integer The bounds can be specified as a type file G Linux http www vaxxine com pegasoft people html book 10 html 20 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada type peopleHeight is new integer range 1 10 type peopleHeightList is array peopleHeight of integer This creates an array from 1 to 10
44. Ada provides a number of important features for Linux programmers e Fast Executables the GNAT compiler produces executables using the same code generator as gcc e User Friendly Ada is easy to learn and use making it a popular choice for introductory computer science courses Its source code is much easier to read that C C or Java e Standardized Ada compilers adhere to a strict standard making Ada programs reliable and portable Even Java hasn t been standardized e Flexibility Ada has many specialized design features that address issues usually ignored by other languages such as real time applications safety critical software and low level hardware access e Faster Cheaper Development As the previously mentioned Zeigler study shows Ada programs tend to have fewer errors that C programs This means you can get your work done faster with less time and money spent on debugging e Scalability Ada is designed for embedded systems and team projects making it an ideal choice for large projects This same scalability and the object oriented features of the language make the file G Linux http www vaxxine com pegasoft people html book 1 html 3 of 5 7 20 2001 11 28 29 AM Big Online Book of Linux Ada Programming 1 Introduction source code prone to a longer lifespan e Ample Libraries The GNAT compiler comes with many general purpose libraries and bindings exist for most of the key Linux libraries e Open Sour
45. BeardLength integer when female gt null end record check syntax In this example a male employee has an additional field called BeardLength when you create a variant record you must specify the descriminant 10 9 Enumerated Types Enumerated types lists of identifiers are created using a type statement type aDogBreed is Unknown Boxer Retriever Shepherd MixedBreed Different enumerated types may have the same values but they are considered different from each other For example type aCatBreed is Unknown Siamese MixedBreed shares two values with aDogBreed but an unknown cat breed is considered different from an unknown dog breed If Ada is confused by the ambiguity you can clarify values with a subtype mark e g aCatBreed MixedBreed Many of the common attributes work with enumerated types including first last and range Especially useful are pred get a previous enumerated identifier and succ get the next enumerated identifer Specific values can be assigned using a for clause so the enumerated type can reflect an external integer value such as error codes with ada text_io unchecked_conversion use ada text_io file G Linux http www vaxxine com pegasoft people html book 10 html 22 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada procedure enumeration_fun is a demonstration of Ada 95 enumerated types type vowels
46. Big Online Book of Linux Ada Programming Appendix E 0x00005307 0x00005308 0x00005309 0x0000530A 0x0000530B 0x0000530C 0x0000530D 0x0000530E 0x0000530F 0x00005310 0x00005311 0x00005312 OscOQDOS SIS 0x00005314 0x00005315 0x00005316 CDROMSTOP void CDROMSTART void CDROMEJECT void CDROMVOLCTRIL const struct cdrom volecruril CDROMSUBCHNL struct cdrom subchnl I O CDROMREADMODE2 const struct cdrom msf MORE CDROMREADMODE1 const struct cdrom msf MORE CDROMREADAUDIO const struct cdrom read audio MORE CDROMEJECT SW int CDROMMULTISESSION struct cdrom multisession I O CDROM GET UPC struct 4 enar pls p CDROMRESET void CDROMVOLREAD Struct carom volete CDROMREADRAW const struct cdrom_msf MORE CDROMREADCOOKED const struct cdrom_msf MORE CDROMSERK const Struct cdrom mer include linux cm206 h 0x00002000 0x00002001 include linux cyclades 0x00435901 0x00435902 0x00435903 0x00435904 0x00435905 0x00435906 0x00435907 0x00435908 0x00435909 CMA2DOCIL GET STAT ant CM206CTL GET LAST STAT int h CYGETMON struct cyclades monitor CYGETTHRESH int CTSETTHEESH Et CYGEIDERBTHEESH int CYSETDEF THRESH int CYGETTIMEOUT ant CYSEITIMEOUT aint CYGETDEFTIMEOUT int CYSETDEFTIMEOUT dine lt include linux ext2_fs h gt 0x80046601 0x40046602 0x80047601 0x40047602 EXT2 IOC GETFLAGS int EXIZ TOC IS SETEL LACS const ant BEATZ OC CETV
47. G Linux http www vaxxine com pegasoft people html book 11 html 26 of 39 7 20 2001 11 33 47 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming entry add amount integer protected body CountingType is entry add amount integer when runningTotal lt 100 is begin runningTotal runningTotal amount end add Like tasks you can create protected types by declaring the specification with protected type instead of protected You can then create arrays of protected items or declare protected items dynamically This covers the basics of Ada s multithreading capabilities There s much more that Ada can do If you are writing complicated multithreading programs you re encouraged to investigate the Ada Reference Manual for more information 11 12 Ada Text Streams A stream is a sequential transmission of different types of data When data is written to a stream the stream converts the data to a form suitable for transmission When the data is read it s converted from the stream s format back to its original form A practical example is saving tagged records belonging to the same class to a file Ada s syntax for using streams is a bit cumbersome Like tagged records some of the features are implemented using attributes and others are found in standard packages The Ada Streams Stream IO can write heterogeneous data to a text file and then read it back again This package contains a number of subpr
48. G Linux http www vaxxine com pegasoft people html book 99_e html 12 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E 0x00005607 VT WAITACTIVE int 0x00005608 VT DISALLOCATE int 0x00005609 VT RESIZE const struct vt sizes sgOOUSODA VI RESIZEX const strict vt consrze More arguments Some ioctl s take a pointer to a structure which contains additional pointers These are documented here in alphabetical order CDROMREADAUDIO takes an input pointer const struct cdrom read audio The burt ticld points to an output buffer of length CDROMREADCOOKED CDROMREADMODE1 CDROMREADMODE2 and CDROMREADRAW take an input pointer const struct cdrom msf They use the same pointer as an output pointer to char The length varies by request For CDROMREADMODE1 most drivers use CD FRAMESIZE but the Optics Storage driver uses OPT BLOCKSIZE instead both have the numerical value 2048 CDROMREADCOOKED char CD FRAMESIZE CDROMREADMODE1 char CD FRAMESIZE or OPT BLOCKSIZE CDROMREADMODE2 char CD FRAMESIZE RAWO CDROMREADRAW char CD FRAMESIZE RAW EOL ENSLAVE EOL EMANCIPATE EOL GELSLAVECFG EOL SETSBhAVECEG EQL GETMASTERCFG and EQL SETMASTERCFG take a struct ifreg The ifr data field is a pointer to another structure as follows EQL ENSLAVE const struct slaving request EQL EMANCIPATE const struct slaving request EQL GETSLAVECFG struct slave config I O EOL SEISLA
49. LOS String Ihis 29 also on standard error align 4 neg Longa Long 30 DOS StIIIng But this Ls Of Standard Our eile Y ses align 4 globl ada stderr type ada stderr Q function ada stderr pushl ebp movl esp ebp movl LCO eax movi S LCl sedx pushl edx pushl eax call ada text io put line 2 push sd call ada text io new line 2 movl LC2 eax movl LC3 edx pushl edx pushl eax call ada text io standard error pushl eax call ada text io put line movl LC4 eax movl LC5 edx pushl edx pushl eax call ada text io put line 2 addl 32 esp pushl 1 call ada text io new line 2 file G Linux http www vaxxine com pegasoft people html book 7 html 9 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Programming 7 Optimizing Your Project call ada text io standard error pushl eax call ada text io set output movl LC6 eax movil hC7 edx pushl edx pushl eax call ada__text_io__put_line__2 call ada text io standard output pushl eax call ada text io set output movl LC8 eax movl LC7 edx pushl edx pushl eax call ada text 1o put line 2 movl ebp esp popl ebp CeT Lfel Size ada stderr Lfel ada stderr ident GCC GNU 2 8 1 Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 7 html 10 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Programming 8 Debugging Your Projec
50. Print Sales were good Now close the pipe EndPrinting Put Line Program done check the printer end printer2 file G Linux http www vaxxine com pegasoft people html book 16 html 27 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming 16 12 Memory Management The amount of virtual memory for a process depends on the processor For Intel x86 processors your program and data must be 3 Gigabytes or less An additional 1 Gigabyte per process is reserved for the kernel accounting for the full 32 bits of addressing space not finished KB 16 13 The Virtual Consoles The virtual consoles are controlled by the ioctl function not finished KB The following example catches SIGWINCH signals and reports the new window size with Ada Interrupts Names useAda Interrupts package sigwinch is protected SignalHandler is procedure SizeChangeHandler pragma Attach Handler SizeChangeHandler Names SIGWINCH this handler will catch SIGWINCH signals a window size change end SignalHandler end sigwinch with Ada Text IO useAda Text IO package body sigwinch is imported C functions TIOGWINSIZ constant integer 16 5413 get window size ioctl request type WindowSizeInfo is record row column unusedl unused2 short_integer end record pragma pack WindowSizeInfo the window size information returned b
51. Rings can be bounded or dynamic 18 1 12 Maps Maps are ordered pairs of related items Each item is related to a value which may or may not be the same type Maps relate items to values by binding them The Maps package provides the following subprograms e Clear destroy a map e Bind relate an item to a value e Rebind relate an item to a different value e Unbind remove the relationship between an item and its value file G Linux http www vaxxine com pegasoft people html book 18 html 17 of 26 7 20 2001 11 38 18 AM Big Online Book of Linux Ada Programming 18 Data Structures e Extent return the number of relationships e Is Empty true if there are no relationships e Is Bound true if the item is related to a value e Value Of the value an item is related to e Visit a read only procedure to traverse the map e Modify a procedure that traverses the map making changes Maps are implemented with a hash table and caching Maps can be bounded dynamic unbounded or synchronized Maps are useful as translation tables 18 1 13 Binary Trees Binary trees are lists with two successors instead of 1 named left and right The items in the tree are not sorted by the Booch component The program has full control on how items are added to the tree Programs walk the tree by moving the root of the tree up and down the links to the items Left Child follows the left child link Right Child follows the right chi
52. Set Output Standard Output Close SpoolFile PrintkEile SpoolPathn P Put_Line Program done check the printer end printer Although this program will work for simple applications another improved program to print using pipes is discussed below The system function is convenient but it has a couple of important drawback e It s slow it always opens a shell even if you re only using the shell execute some other program e It s a security risk the shell could have aliases defined and what you thought you were running may not be what actually runs GNAT s OsLib provides a subprogram like system called spawn It executes a Linux program without starting a shell first Spawn requires a bit of setup to use You have to define an array of access type arguments for the command Once you invoke spawn it returns a boolean value indicating whether the spawn succeeded or failed The following excerpt is from an example program in the OSLib section covered below file G Linux http www vaxxine com pegasoft people html book 13 html 4 of 15 7 20 2001 11 35 51 AM Big Online Book of Linux Ada Programming 13 Linux Introduction Arguments Argument List 1 1 an argument list for 1 argument bs 6 constant string gt Aog lsi the program we want to run WasSpawned boolean RootDir aliased string begin Arguments 1 RootDir unchecked access unchecked to avoid useless in this case
53. This is a Linux specific function function fcntl fd file id operation gt F SETSIG arg long integer pragma import C fcntl Set the signal number of the signal sent when input or output becomes possible on a file zero being the default SIGIO Use this to set up a signal handler alternative to the kernel calls select and poll See the man page for more information This is a Linux specifc function 16 8 Opening and Closing Files The standard Ada packages Text IO Sequential IO and Direct IO are suitable for simple projects but they were never intended as a complete solution for large scale applications If you want to do efficient file manipulation you ll have to write your own routines based on kernel calls or the standard C library gnat s OSLIB package contains low level commands to work with UNIX files However you can always create your own The following bindings assume these types have been defined type file id is new integer type mode t is new integer type off t is new long integer type size t is new long integer subype ssize t is size t function open path string flags integer mode mode t return file ig pragma import c open Open a file and return and file identification number flags indicates how the file should be opened and what kind of access the file should allow defined in usr include fcntlbits h Mode defines the access permissions you want on
54. You can later use your proposal as the basic text for an announcement of the release of your program 20 2 The Design Phase When it comes time to begin designing the basic layout of a project remember that Ada has features designed just for this task Break up your project into a series of packages and include basic type definitions and subprograms using pragma stubbed Remember that the design doesn t have to be perfect but you need a starting place for you and your teammates to discuss the work Use lots of comments to avoid continually explaining the purpose of each package and it s contents When you have a basic layout compile each of the specs to make sure the design is sound 20 3 The Development Phase Check list Did you use pragma pure preelaborate or no_elaboration_code whenever possible Did you use pragma Normalize_Scalars whenever possible 20 4 The Alpha Beta Release Check list for first alpha or beta release Check your integers did you use integer when short_integer or long_integer would have been better file G Linux http www vaxxine com pegasoft people html book 20 html 1 of 7 7 20 2001 11 38 49 AM Big Online Book of Linux Ada Programming 20 Developing Your Project Do you have pragma Optimize set in all of your packages Did you use pragma Pack all arrays and records that need packing Do some need packing turned off Did you assign your access types to a debug pool in order to check for run time erro
55. You need to chose the best approach for your particular project 7 5 Working with the Assembly Source Assembly language is the low level programming language for working with the hardware of a particular computer Using assembly language you can access the processor registers use unusual features of the processor and dictate exactly which operations the processor performs Assembly language programs are usually several times smaller and faster than programs written in high level languages but they are also several times harder to build maintain and debug The Linux assembler is called gas the GNU assembler Like GNAT and C gas works through gcc To assemble an assembly language source file simply run gcc The compiler will recognize the assembly language file and will assemble it using gas If you want to view the assembly source code of your Ada program use the c S fverbose asm options when compiling GNAT will create a file with a s suffix containing the assembly source You can view it or even edit it and assemble afterwards bane the instructions produced by the compiler and then assembling afterwards is known as hand optimizing This technique is typically used for high performance applications such as games where the programmer needs to get the maximum performance from the hardware file G Linux http www vaxxine com pegasoft people html book 7 html 7 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Pr
56. anUnrelatedClass a field not an extension end record anMIExample is a tagged record belonging to aClass not to anUnrelatedClass If you extend anMIExample it will inhert F1 from its parent class Since anUnrelatedClass UC is nested you can still access it as a field using the prefix UC BETTER EXAMPLE KB 11 6 Private Objects Unless a tagged record class is very small it s kept in it s own package When you put a class in a package you can use the package to hide the details of the class and to make parts of the class inaccessible to the outside world package customers is type AbstractCustomer is abstract tagged private type BasicCustomer is new AbstractCustomer with private private type AbstractCustomer is new abstract tagged record name string 1 80 end record type BasicCustomer is new AbstractCustomer with SalesCategory integer end record end customers By declaring a tagged record as private we eliminate all access to the fields in the record Anybody who wants to change the value of the fields must do it through any subprograms we provide In object oriented programming it s a good idea to make as many tagged records private as possible the same as other private types That way if you want to change the contents of the tagged record programs that use your class will not have to be changed C Ada does not have protected objects but protected objects can be simulated using
57. char the array contains chars Element Array char array the unbounded type Default Terminator gt char val O the terminator value ASCII NUL Vi use StringPtrs need this to make and visible Siew Owe BI She dea biete e ie aede ode oye P The use clause is very important Without it the arithmetic operators would not be directly available because they would be hidden inside the StringPtrs package Pointers created using Interfaces C Pointers are access types and can be used like any other access type PUL mine e SEDET is poincing oO che Character SES EE rd lu However unlike other access types they have new pointer arithmetic features Addition and subtraction is performed the same way as in C by specifying how many positions in the array to move To move strptr ahead 2 index positions in a string add 2 to it SEE T SEDED Since Ada has no increment or decrement operators two procedures are provided to move a pointer forward or backward by one array position Increment strptr forward one position Decrement strptr back one position The package also makes four additional subprograms available The Virtual Length function returns the length of an array up to end of the array or until a terminator is found If no terminator do you get a storage error KB The Value function returns a slice from the array from the position of the pointer to the end of the
58. converted to integers do the numbers round to the nearest integer or is the decimal part simply discarded In C this is system dependent System V based UNIX s usually round to the nearest integer while some other systems discard the decimal part Others like HP UX the number rounds towards the nearest even integer providing the floating point number is exactly half way between two integers On Linux C truncates the decimal part In Ada the way numbers round are strictly defined by the language you can be sure that no matter what operating system you are using floating point numbers converted to integers will always round to the nearest integer If the floating point number is half way between two integers it will round up The following program demonstrates floating point rounding file G Linux http www vaxxine com pegasoft people html book 10 html 5 of 29 7 20 2001 11 33 05 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada with ada text_io ada float_text_io use ada text_io ada float_text_io procedure rounding is rounding example procedure ShowRounding f float is show the floating point value and show the value after it s converted to an integer int value integer begin Pute EFlloak number 1 Put f fore gt 5 aft gt 3 int value integer f Pue Line rounds co Y e Tint Va ue IT c end ShowRounding begin Put_Line This is a demonstra
59. move left or right to the next menu item in lists move up or down one line in the list in scroll bars adjust up or down by 1 Page Up or Control P move up one page in a list in scroll bars same as up and down arrows Page Down or Control N move down one page in a list in scroll bars same as up and down arrows Home Key or Control Y move to the top of a list in scroll bars go to the top End Key or Control E move to the bottom of a list in scroll bars go to the bottom Tab Key move to the next item in the window Control T move to the previous item in the window Return Key or Spacebar activate a button When inside of a list box the movement keys move you around the list If you are on the Linux console pressing alt and the hilighted letter will always jump to the appropriate object even if you re inside a list box or the notepad Editing Keys Control 6 mark text only works in edit lists Control X clear text in lists clear the current line or lines if control 6 used Control B copy text in lists copy the current line or lines if control 6 used Control V paste text in notepad paste the last line copied Misc Keys ESC Key or F1 bring up the accessories menu Control L redraw the screen file G Linux http www vaxxine com pegasoft people html book 15 html 11 of 13 7 20 2001 11 36 38 AM Big Online Book of Linux Ada Programming 15 Free Ada
60. procedure winch is begin Put Line This program catches SIGWINCH signals New Line Put Line It will stop running is 60 seconds If you are using file G Linux http www vaxxine com pegasoft people html book 16 html 29 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Put_Line X Windows move the window to send signals New_Line delay 60 0 run for 60 seconds end winch 16 14 Making Database Queries 16 14 1 mySQL mySQL pronounced my ess que ell is a free high performance database from T c X It s available for a number of platform including Linux The mySQL home page is http www mysql org mySQL comes with a C library called mysglclient If an Ada program links in this library with Imysqlclient it can access mySQL databases You issue commands to the database called queries using the database language SQL pronounced sequel Connecting to a mySQL database is a six step process 1 Open a new connect using mysql init Login using mysql real connect Perform database queries with mysql query or mysql real query real query allows binary data in the query Retrieve the results using mysql store result or mysql use result Free any memory using mysql free result Nn d C N Close your connection with mysql close Usually a null point or non zero integer result indicates an error mysql errono returns the error Complete do
61. sample controlled tagged record and a pointer to same procedure Initialize sr in out SampleRec procedure Finalize sr in out SampleRec procedure Adjust sr in out SampleRec these are required for controlled tagged records end sample with Ada text io use Ada text io file G Linux http www vaxxine com pegasoft people html book 11 html 9 of 39 7 20 2001 11 33 45 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming package body sample is just print messages to show that these are working procedure Initialize sr in out SampleRec is begin Put_Line Initialize Initialized tagged record end Initialize procedure Finalize sr in out SampleRec is begin Put_Line Finalize Finalized tagged record end Finalize procedure Adjust sr in out SampleRec is begin Put_Line Adjust Adjusted tagged record end Adjust end sample Here is the output The records being affected are noted in bold Initialize Initialized tagged record sr3 This is the first line of the program This is an example of controlled tagged records Executing srpl new SampleRec Initialize Initialized tagged record srpl all Executing srp2 srpl copying a pointer Executing sr3 srpl all copying a record pointed to Finalize Finalized tagged record sr3 before record is copied Adjust Adjusted tagged record sr3 a
62. similar to Ravanscar e Restrictions disable particular language features no_run_time also enforces restrictions because the Ada run time library is not available More information on the usage of these pragmas is available in the Gnat documentation lt Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 8 html 6 of 6 7 20 2001 11 32 24 AM Big Online Book of Linux Ada Programming 9 Team Development 9 Team Development lt Last Chapter Table of Contents Next Chapter gt 9 1 Change Logs The Change Log Creating a change log is the easiest method to document changes you ve made in a project A change log is a text file usually called CHANGES containing an explaination of all recent changes in a project For example if you are working on an open source project and you add support for encrypted passwords you might document this by writing Nov 1 added password support to file passwords adb If anyone was going to add password support to your project they can quickly see that you ve already done it Or if somebody was adding additional features to the passwords c file they will know that they may have to change their work since you ve already changed the same file The change log is popular on open source projects involving few programmers because there s little chance of two programmers modifying the same source file simultaneously The Formal Change L
63. you will have to explicitly link them in For example to use the C math library libm a would have to be explicitly linked using lm In C functions can have parameters that change value while in Ada this kind of function is not allowed because functions can only have in parameters To get around this problem gnat defines an import valued procedure pragma Suppose you have a C function like this int SomeCFunction char param Normally there is no way to represent this kind of function in an Ada program However we can import it by treating it as a procedure using the import valued procedure pragma procedure SomeCFunction result out integer param in out integer pragma import C SomeCFunction pragma import valued procedure SomeCFunction The import valued procedure pragma tells gnat that this procedure corresponds to a C function the first parameter is the result of the C function and the remaining parameters correspond to the parameters of the C function The first import pragma is not strictly required but ACT recommends using it You can t import identifiers created by the define statement since they only exist before a C program is compiled You also can t import types except for C classes since types have no address in memory KB true There is one case where these tricks fail when the C function returns a pointer to a C variable that it declared In this case the function is returning a new C point
64. 0 13 4 S 16 8 Gl ES gt ih TS ll The sorted table is 0 13 124 225 OL 4 13 5 The second gnat bubble_sort_a uses callbacks instead of a generic package Use this package if you want to conserve memory by avoiding a lot of instantiations of the generic bubble_sort_g Remember that callbacks must be global so we can t simple pass the local subprograms we created in bubble1 This time we must store the array and subprograms in a separate package with text_io gnat bubble_sort_a inttable use text_io inttable procedure bubble2 is begin Put_Line This is an example of bubble sorting an integer table New_Line Parte aime ihe table begins ass 5 ShowTable gnat bubble sort a Sort n gt iti llast Move gt MoveIntegers access Lt gt CompareIntegers access sort elements 1 to top of it array New Line Put Line The sorted table is ShowTable end bubble2 package inttable is zone cable to SOrE type IntegerTable is array 0 5 of integer it eo IntegerTable 0 13 4 D 16 8 jer Define the items required by a callback gnat bubble sort these must be global to work procedure MoveIntegers From To natural move one item in the table from From position to To position file G Linux http www vaxxine com pegasoft people html book 12 html 25 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12
65. 15 2 9 OS Package 15 2 10 UserIO Overview 15 2 11 Appearance and Keys 15 3 Using Ncurses not finished 15 4 Using GTK Widgets not finished 15 5 Using Motif Widgets not finished 15 6 Using the TASH TCL Binding not finished 15 7 Using the Mesa OpenGL Binding not finished 15 8 Engine 3D not finished 16 Advanced Linux Programming 16 1 Writing Your Own Bindings 16 2 Linux Errors and Errno 16 3 The Linux Clock 16 3 1 Basic time functions 16 3 2 Timeval Calls Microsecond Accuracy 16 3 3 Functions Using the tm Record 16 3 4 Time as a String 16 3 5 Timer Functions 16 4 Process Information 16 4 1 Ownership 16 4 2 Other Functions 16 5 Environment Variables 16 6 Multitasking 16 7 Linux File Operations 16 8 Opening and Closing Files 16 9 Directories file G Linux http www vaxxine com pegasoft people html book book html 7 of 10 7 20 2001 11 22 56 AM The Big Book of Linux Ada Programming 16 10 Stdio Files 16 11 Stdio Pipes 16 12 Memory Management 16 13 The Virtual Consoles 16 14 Making Database Queries 16 14 1 mySQL not finished 16 14 2 PostgreSQL not finished 16 15 Dynamic Loading not finished 16 16 A Word on Device Drivers 16 17 Linux Sound 16 17 1 Detecting a Sound Card 16 17 2 Playing Sound Samples 16 17 3 Using the Mixer 16 17 4 Recording Sound Samples not finished 16 18 Audio CDs 16 19 Kernel Pipes not finished 16 20 Shared Memory not finished 16 21 Message Queues
66. 31 mon gt integer month 0 11 year integer year wday integer day of the week 0 6 yday integer day of the year 0 365 isdst integer gt 0 is daylight savings time O not lt 0 unknown end record You will also need the Address To Access Conversions package to convert C pointers to tm record into Ada access type pointers package TmPtrs is new System Address To Access Conversions tm function localtime time in out time t return system address pragma import C localtime Change the time into a tm record making changes for the current time zone time is the C pointer to the seconds since 1970 function gmtime time in out time t return system address pragma import C gmtime Change the time into a tm record for UTC Coordinated Universal Time time is the C pointer to the seconds since 1970 function mktime tm system address return time t pragma import C mktime Convert a tm record into the seconds since 1970 To get the current time in tm format seconds since 1970 long integer file G Linux http www vaxxine com pegasoft people html book 16 html 6 of 47 7 20 2001 11 37 13 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming tm rec em time seconds since 1970 tm TmPtrs To Pointer localtime seconds since 1970 address all 16 3 4 Time as a String function asctime tm system address return st
67. 4 2 Other Functions function kill uid signal integer return integer pragma import C kill Stop a child process that your process has started the same as using the kill command at the shell prompt More accuately send a signal to a child process some signals won t stop the child process Example Result kill MyRunawayChildUID 15 send SIGTERM terminate signal file G Linux http www vaxxine com pegasoft people html book 16 html 8 of 47 7 20 2001 11 37 13 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Signal handling in general is easier through Ada Interrupts than through Linux kernel calls because of their heavy reliance on C macros KB function alarm seconds Interfaces C unsigned return Interfaces C unsigned pragma import C alarm After the specified number of seconds cause a SIGALRM interrupt in the current process 16 5 Environment Variables Environment variables can easily be set and read with Ada Command_Line Environment package You can also set them directly through the standard C library function putenv str string return integer pragma import C putenv Define a Linux environment variable putenv literally saves a pointer to the string therefore the string must be global or a literal Example Result putenv TERM vt102 amp ASCILNUL function getenv str string return string pragma import C putenv Read the v
68. A rec size 66 46 16 Transmitting HITP command Sent 81 bytes Web Page Server Results lt x Date Server Wed Erag ATTE OO TOK 29 Mar 2000 02 32 56 GMT Apache 1 3 3 Last Modified 1f31 406 382a23e2 dae Ll Now OOO MUA OS al NIE Traffic Server 3 0 3 us eis eN EC SN D HTML EN CONTENT David BOCCON CONTENT Ada AdaPower power source code free treasury E description CONTENT The Ada Source Code Treasurey contains algorithms and articles for Ada developers CONTENT revealtrans duration 2 0 transition 3 gt Acecepe kanges ses Content Length 1030 Content Type text html Age 39 Viar ATIE Ae OT teet L2 lt DOCTYPE HIME PUBLIC Y TETE DT lt HTML gt lt HEAD gt lt META NAME author META NAME keywords repository gt lt META NAMI components procedures lt META http equiv Page Enter lt TITLE gt AdaPower com lt TITLE gt lt LINK href mailto David Bot lt HEAD gt lt FRAMES EN COLS 120 lt E RAME SRC buttons html marginwidth 0 noresize SE lt NOFRAMES gt lt meta MUTE I lt body bgcolor lt a href body html lt nd BODY BODY lt NOFRAMES gt lt FRAMESET gt lt HTML gt RAME SRC 2 http www adapower
69. Ada packages file G Linux http www vaxxine com pegasoft people html book 11 html 11 of 39 7 20 2001 11 33 45 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming 11 7 Generics Ada allows you to create source code templates called generics With generics you can specify a routine with only general information about the kinds of types the routine can work on Later a programmer instantiates the generic by giving a type Generics are useful for things like sort routines which work basically the same way on different data types C Generics are similar to C templates Ada contains several standard generic procedures The most important one is unchecked_deallocation This long winded procedure deallocates memory allocated with new In order to free up memory you must instantiate an unchecked_deallocation for each access type you are going to use new on You have to specify both the access type and type of data that is being pointed to with unchecked_deallocation type booleanPtr is access all boolean procedure Free is new unchecked_deallocation boolean booleanPtr Free is a new version of unchecked_deallocation compiled for booleanPtr s to a boolean type Ada was designed for the possibility automatic storage recovery that everything that was allocated in a subprogram would be deallocated automatically when the subprogram is left Unfortunately gnat was implemented without this feature and all memor
70. Ada pointers to a string subtype DirlInfoCPtr is System Address subtype DirEntCPtr is System Address two C pointers System Address types renamed for clarity below type DirEnt is record inode long integer inode number offset integer system dependent offset2 unsigned char system dependent reclen unsigned short system dependent name string 1 257 name of file end record pragma pack dirent dirent is defined in Usr sre e linus direme a package DirEntPtrs is new System Address_To_Access_Conversions DirEnt use DirEntPtrs Convert between C and Ada pointers to a directory entry procedure getcwd buffer out string maxsize size t pragma import C getcwd file G Linux http www vaxxine com pegasoft people html book 16 html 22 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming function get_current_dir_name return System Address pragma import C get current dir name function mkdir path string mode size t return integer pragma import C mkdir function rmdir path string return integer pragma import C rmdir function opendir path string return DirInfoCPtr pragma import C opendir function closedir info DirlInfoCPtr return integer pragma import C closedir functio
71. Big Online Book of Linux Ada Programming 11 Advanced Ada Programming type office_number is new contact_info with record office integer end record procedure free is new ada unchecked deallocation contact info elass Contact PEE A Stream File and Its Stream stream file Ada Streams Stream IO File Type the stream Ada Streams Stream IO Stream Access contact omisi pEr begin Put_Line An example of Ada Streams Stream_IO and a Class Put Linel M n nene ILS iE eds ese esed estieseccucse Duel uL New Line Create stream file out file contact list stream Put Line Created a stream file open the stream file the stream stream stream file get a stream representing the file s contents contact new phone number phone gt 1 905 555 1023 contact intoiclass output the stream Contact allln pree contact Jy Put_Line Wrote a phone number write a record contact new office number office 8023 contact dxnfto class output the stream comtact all 5 free contact Put Line Wrote an office number write a record Close stream file New Line close the stream file Read Them Open stream_file in file contact_list stream Put_Line Opened a stream file open the stream file the stream stream stream
72. Bindings Control A or F2 execute a keyboard macro 15 3 Using NCurses Ncurses is a free toolset for drawing on text screens such as the Linux console not finished 15 4 Using GTK Widgets GTK the Gimp ToolKit is a widget set or sometimes called a control set These are the same widgets used by the Gimp drawing program Unlike Motif and QT widgets GTK uses an LGPL license making it very popular for new Linux software include the GNOME desktop project GTK also contains 2D drawing operations GTK is available for download from the GTK web site at http www gtk org GtkAda can be downloaded from the ALT web site or from its home page at http ada eu org gtkada GtkAda is an Ada95 binding of Gtk version 1 2 0 It allows you to develop graphical applications in Ada95 using Gtk General GTK documentation and a tutorial written with examples in C are available from the GTK web site not finished 15 5 Using Motif Widgets Motif pronounced Moe Teef is an X Windows widget standard created by the Open Software Foundation OSF a group of several UNIX companies Motif is built for the stanadard X Windows library Xt With Motif you can create windows and dialog boxes menus buttons scrolling lists and the like Motif is a registered trademark of OSF LessTif pronounced Less Teef is an open source compatible version of Motif 1 2 with some extensions licenced under LGPL It is available for download from the L
73. Calls 4 Summaries and Data Structures For example the C library call manual pages are located in usr man man3 The easiest way to create a simple man page for your program is to find a similar man page and make a copy Use this copy as a basis for your new man page You can perform a simple test on your new man page by groff mypage less To convert your page to another format use groff mypage gt mypage ps to create a PostScript version of your man page or use the Tdvi switch to create a TeX dvi file Use one of the free conversion programs available on the Internet to translate the PostScript file to another format file G Linux http www vaxxine com pegasoft people html book 20 html 4 of 7 7 20 2001 11 38 49 AM Big Online Book of Linux Ada Programming 20 Developing Your Project 20 8 Linux Software Map Entry The Linux Software Map http www ExecPC com Ism is a web site devoted to tracking Linux software Software registered with the map uses a LSM Linux Software Map file to describe programs One important Linux site Metalab http metalab unc edu requires a LSM file for every program in its archive A Linux Software Map entry is a text file ending with a Ism suffix It s formatted like an email message header There are named fields that begin with a keyword and a colon followed by the data for that field Continue lines by pacing over beneath the previous line Here is an example LSM entry Begin3
74. EMLINK Bi foomeylns EPPE B jBeknpp S EDOM B3 Math argument out of domain of func ERANGE B4 Math result not representable EDEADLK fs Resource deadlock would occur SSS ENAMETOOLONG B6 Filename toolong ENOLKK B7 Norecordlocksavailable SOSOSCS ENOSYS B8 Fundionmoimplemened ENOTEMPIY 9 DWeoymoempy LOOP Wo Too many symbolic links encountered SS EWOULDBLOCK same as EAGAIN Operation would block ENOMSG Wm No message of desired type EIDRM w Jdm fierrmowd ECHRNG a Channel number out of range EL2NSYNC Ws Leve not synchronized EDHLT Ww oaea EDRST 4 edimea ELNRNG A8 lknumbrouofmmg EUNATCH o Protocol driver not attached ENOCSIL o No CST structure available EDHLT Bi aea EBADE 52 mwaidexhage EBADR s invalid request descriptor EXFUL p Echag ENONNO o o Mome EBADRQC b6 Jmvaidrqustcode EBADSLT 57 mwids EDEADLOCK same as EDEADLK EBF ONT 59 Bad font file format EN OSTR 60 Device not a stream EN ODATA 61 IN o data available file G Linux http www vaxxine com pegasoft people html book 99_b html 2 of 4 7 20 2001 11 39 27 AM Big Online Book of Linux A
75. G Linux http www vaxxine com pegasoft people html book 16 html 24 of 47 7 20 2001 11 37 15 AM i Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Result CloseDir DirInfo end direct This program demonstrates Linux s directory functions The current path simplified is home ken ada trials The current path is home ken ada trial temp directory created temp directory removed Directory home ken ada contains these files temp all zip README od x Zap sm posix cgi tia x ie eireyalgte o e IE PIE text only original lintel texttools smbeta2 zip Erials plugins ECXE TOOLS zip The last position is texttools zip The first position is 16 10 Stdio Files C has a library called stdio or STanDard IO which contains standard operations for text files Loosely stdio is the C equivalent of Ada s Text IO package The standard gnat package cstreams provides a thin binding to many of the stdio functions In this section we ll looking at using stdio directly Some of the stdio functions can t be used from Ada because of differences in the languages For example printf the standard command for writing to the screen has a variable number of parameters Because there s no way to express a variable number of parameters in Ada printf can t be imported into Ada with System type AStdioFileID is new System Address
76. G Linux http www vaxxine com pegasoft people html book 99_e html 10 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E 0xC004500A SNDCTL_DSP_SETFRAGMENT int I O 0x8004500B SNDCTL_DSP_GETFMTS int 0xC0045005 SNDCTL DSP SETFMT int I O sceDOC5ODC SNDCTL DSP GETOSPACE struct audio but into scgoQosoD0D SNDOTLODSEP GETIGPACE struct audio buf inte 0x0000500E SNDCTL DSP NONBLOCK void 0x80045002 SOUND PCM READ RATE int 0x80045006 SOUND PCM READ CHANNELS int 0xS90045005 SOUND POM READ BITS int 0x80045007 SOUND PCM READ FILTER int 0x000043500 SNDCTL COPR RESEI Vond OxCFBO04301 SNDCTL COPR LOAD const struct copr buffer 0xC0144302 SNDCIL COPR RDATA struct copr debug but 1 0 0xC01l44303 SNDCTL COPR RCODE struct Copr debug but I 0 0x40144304 SNDCTL COPR WDATA const struct copr debug buf 0x40144305 SNDCIL COPR WCODE const struct copr debug buf 0xC0144306 SNDCTL COPR RUN struct copr debug buf I O 0xC0144307 SNDCTL COPR HALT struct copr debug buf I O Ox4PA44308 SNDCTIL COPR SENDMSG Const Struck Copr msg UxSUA44309 SNDCILCCOPR RCVMSG Struct Copr meq 0x80044D00 SOUND_MIXER_READ_ VOLUME int 0x80044D01 SOUND MIXER READ BASS int 0x80044D02 SOUND MIXER READ TREBLE int 0x80044D03 SOUND MIXER READ SYNTH int 0x80044D04 SOUND MIXER READ PCM int 0x80044D05 SOUND MIXER READ SPEAKER int 0x80044D06 SOUND MIXER READ
77. GNAT Regexp procedure regex is procedure TestMatch re Regexp s string is begin if Match s re then Put Line s amp matches th xpressiom j else Put Line s amp doesn t match the expression end if end TestMatch Criteria Regexp begin Put Line This program demonstrates GNAT s regular expression Put Line capabilities These are used to find text that match Puts imine Ta certain pattern J New_Line UNIX Regular Expressions Put Line A globbing pattern is a UNIX shell style pattern matching Put Line The pattern a matches anything starting with the letter a Criteria Compile a Glob gt true Case Sensitive gt true New Line TestMatch Criteria accounting TestMatch Criteria President TestMatch Criteria sundries New Line BNF Expressions Put Line A non globbing pattern is a BNF pattern as used in the Ada Put Line Reference Manual For example a a z means characters Put_Line beginning with a and with any number ot letters following Criteria Compile a a z false true New_Line TestMatch Criteria accounting Jy TestMatch Criteria sales New_Line end regex This program demonstrates GNAT s regular expression capabilities These are used to find text that match a certain pattern file G Linux http www
78. I O L SEQ GETOUTCOUNT int CTL SEQ GETINCOUNT int L SEQ PERCMODE void CTL FM LOAD INSTR const struct sbi instrument Lh SEO IESIMIDI const int CTL SEQ RESETSAMPLES const int L SEQ NRSYNTHS int CTL SEQ NRMIDIS int L MIDI INFO midi info I O CTL SEQ THRESHOLD const int L SYNTH MEMAVL int I O CIL FM 40P ENABLE const int IL PMGR ACCESS struct patmgr info I O CTL SEQ PANIC void L SEQ OUTOFBAND const struct seq event rec TMR TIMEBASE int I O TMR START void TMR STOP void TMR CONTINUE void TMR TEMPO int I O TMR SOURCE int I O TMR METRONOME const int TMR SELECT int I O PMGR IFACE struct patmgr info I O J MIDI PRETIME int I O MIDI MPUMODE const int MIDI MPUCMD struct mpu command rec I O DSP RESET void DSP SYNC void DSP SPEED int I O DSP STEREO int I O SNDCTL DSP GETBLKSIZ int I O SOUND PCM WRITE CHANNELS int I O SOUND PCM WRITE FILTER int I O SNDCTL DSP POST void SNDCTL DSP SUBDIVIDE int I O ZZZZZZZZZZZZZZZZA Seo le see se Ss bee ee es gun cU H H t H H t H Er wae SDD H H Z J Q H zi g Q H Z UO Q H Z g Q x zi JO Q H zi J Q H zi g Q H ANNANANNANNNANNNANNNNNANNNANNNANNANNNANNNNNMNN EZ Eun eh an ee zZ dogo ugy J QU IQ CO Or Oe ele al estes es zi J Q H Z g Q EA lest Ir rel ee oe ee joe ES E E EE file
79. K K K K K K K TOLCEONT Const sSteuce m ehar 13192 IO FONTX struct console font desc TOS CMAR struct eid TO CMAR const struct chaz IOCSOUND int DMKTONE int DGETLED char DSETLED int DGKBTYPE char DADDIO int MORE DDELIO int MORE DENABIO void MORE DDISABIO void MORE DSETMODE int DGETMODE int DMAPDISP void MORE DUNMAPDISP void MORE IO_SCRNMAP struct char IO SCRNMAP const struct char TO UNTSCRNMAR struct a short E TABSZ IO_UNISCRNMAP const struct short 95153 E TABSZ om TOS IO UNIMAPCLR const Struct unimapinit DGKBMODE int DSKBMODE int DGKBMETA int DSKBMETA int DGKBLED int DSKBLED int DGKBENT struct kbentry I O SKBENT const struct kbentry DGKBSENT struct kbsentry I O DSKBSENT const struct kbsentry DGKBDIACKR struct kbdiacrs DSKEDIACR const struct kbdrsors DGETKEYCODE struct kbkeycode I O DSETKEYCODE const struct kbkeycode DSIGACCEPT imt OQ include linux lp h 0x00000601 LPCHAR int 0x00000602 LPTIME int 0x00000604 LPABORT int E TABSZ file G Linux http www vaxxine com pegasoft people html book 99_e html 7 of 15 7 20 2001 11 40 32 AM Pp oTABS UNIMAP struct unimapdesc MORE I O UNIMAP const struct unimapdesc MORE MORE I O IO FONTX const struct console font desc MORE Big Online Book of Linux Ada Programming Appendix
80. Line TIn order traversal gt inOrderShipmentTraversal root OK if not OK then Put_Line The traversal was interrupted end if New_Line Put_Line Pre order traversal preOrderShipmentTraversal root OK if not OK then Put_Line The traversal was interrupted end if New_Line Put Line Post order traversal postOrderShipmentTraversal root OK if not OK then Put Line The traversal was interrupted end if end bintree demo This is a demo of the Booch components binary trees Our tree is 5 6 qt baskets of cherries 7 11 qt baskets of pears 12 bushels of apples 3 skids of peaches file G Linux http www vaxxine com pegasoft people html book 18 html 21 of 26 7 20 2001 11 38 18 AM Big Online Book of Linux Ada Programming 18 Data Structures In order traversal Shipment of 7 BASKET_11QUART S of PEARS Shipment Of 3 SKID S of PEACHES Shipment of 5 BASKET_6QUART S of CHERRIES Shipment of 12 BUSHEL S of APPLES Pre order traversal Shipment of 5 BASKET_6QUART S of CHERRIES Shipment of 7 BASKET_11QUART S of PEARS Shipment of S SERI SEO PEACHES Shipment of I2 BUSHELC S of APPLES Post order traversal Shipmen
81. Novell PF NETLINK Kernel user interface device PF X25 ITU T X 25 ISO 8208 PF AX25 Amateur radio AX 25 PF ATMPVC Access to raw ATM PVCs PF APPLETALK Appletalk PF PACKET Low level packet interface Socket Types SOCK STREAM Two way reliable connection with possible out of band transmission eg TCP IP SOCK DGRAM Datagram Connectionless unreliable messages eg UDP IP SOCK SEQPACKET Sequenced reliable datagram connection SOCK RAQ Raw network protocol access SOCK RDM Reliable unordered datagrams function socket domain soctype protocol integer return integer pragma import C socket Creates a network socket for protocol family domain connection type soctype and a protocol 0 uses the default protocol Returns 1 on an error or else a kernel file descriptor for the socket Example mySocket socket PF INET SOCK STREAM 0 open a standard Internet Socket procedure connect result out integer socket integer addr in out socketaddr addrlen integer pragma import C connect pragma import valued procedure connect Connects to a server on the network socket is the socket to use addr is the machine and service to connect to addrlen is the length of the addr record Returns 1 on an error 0 for success Example connect result webserver webserver size 8 connect to the web server described by the webserver record function shutdown socket how integer
82. Pointer int address int address IntPtrs To Address int pointer Convert between Ada and C pointer types end pointers For example the standard C library function get current dir name returns a pointer to a C string which it declares To use get current dir name we have to instantiate Address To Access Conversions for an array of characters a C string and convert the address to an access type using something like CharArray pointer CharArrayPtrs To Pointer get current dir name There is no other way in Ada to access the array that get current dir name points to KB If your main program is a C program you need to call adainit before any Ada code 16 2 Linux Errors and Errno Most standard C library errors are returned in an integer variable called errno You can examine errno in your Ada programs by importing it errno integer pragma import C errno Errno contains a number for the error returned by the last library function In Multithreading programs be aware errno may not be not thread safe because it can be shared between threads KB document how to do it with threads Linux provides two functions for working with errno error numbers type string255is new string 1 255 type strptr is access string255 error messages are no longer than 255 characters procedure perror message string pragma import C perror Perror prints a standard error description wi
83. Pook ER d for any dereference Pcxnsem Ea o olv pe Generic function for signed E ger exponentiation spooglo scien Pool Global normal heap for GNAT global m types poole system Pool Local normal heap for GNAT local Fem types s powtab System Powten Table table of powers of 10 s stoele System Storage_Elements Standard Ada package Appendix E Table of Contents Glossary file G Linux http www vaxxine com pegasoft people html book 99_f html 9 of 9 7 20 2001 11 40 56 AM Big Online Book of Linux Ada Programming Glossary lt Appendix F Table of Contents End of Book Glossary AARM The Annotated Ada Reference Manual contains the entire text of the Ada 95 standard ISO IEC 8652 1995 E plus various annotations It is intended primarily for compiler writers validation test writers and other language lawyers The annotations include detailed rationale for individual rules and explanations of some of the more arcane interactions among the rules Ada9X the working title of Ada 95 before the language was completed ASIS The Ada Semantic Interface Specification is a layered vendor independent open architecture ASIS queries and services provide a consistent interface to information within the Ada compilation environment Dynamic Polymorphism Polymorphism implemented at run time using a tag to determine the type of item tagged records objects Inheritance Creating new items containing an original i
84. Read procedure Write fid AFileID data AFileElement is write one data item to the file BytesWritten ssize t data2write AFileElement begin can t use data directly because it s an in parameter data2write data size returns the size of the type in bits so we divide by 8 for number of bytes to write is file G Linux http www vaxxine com pegasoft people html book 16 html 18 of 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming C_Write BytesWritten fid data2write AFileElement size 8 if BytesWritten AFileElement size 8 then raise seqio error end if end Write end SegIO You can test SegIO with the following program with SeqIO with Ada Text IO use Ada Text IO procedure SegIOtest is Tenere eO eS exeo package IntIO is new SeqIO integer IntIO is a SegIO for integer numbers A s Ione dE eder SETS RIDTE int2read integer begin Put Line Testing SeqIO package New Line Part 1 Write numbers to a file Enea mex writing numbers I to 10 to a tales t id IntIO Open Tint list txt read gt false for i in 1 10 loop IntlIO Write id i end loop mts Or Close aid Part 2 Read the numbers back from the same file Put Line Reading numbers back id IntIO Open int list txt read gt true for i in 1
85. Semaphore gt BC Support Synchronization Semaphore create a new controlled tagged record container for customers end guarded customers A new guarded bag can now be declared customers customerGuardedBag Guarded Container and the bag can be locked using customerGuardedBag Seize customers Synchronized access by threads is implemented in special versions of the data structure packages for example maps synchronized With synchronized packages the implementation details are hidden from the user Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 18 html 26 of 26 7 20 2001 11 38 19 AM Big Online Book of Linux Ada Programming 19 Specialized Topics 19 Specialized Topics lt Last Chapter Table of Contents Next Chapter gt 19 1 Ada Meets Java 19 1 1 The Java Virtual Machine 19 1 2 JGnat Most of the Gnat tools have a corresponding JGnat version including gnatmake To compile an Ada program into a Java byte code program use jgnatmake jgnatmake hello Table jgnatmake switches JGnatmake Switch Description 000000000 I Consider all files even readonly ali files Fc Compile only do not bind and Tink f Force recompilations of non predefined units Hi fin place Replace existing ali file or put it with source Hnm Use nnn processes to compile k Keep going after compilat
86. Standard Gnat Packages function CompareIntegers left right natural return boolean compare two items in the table and determine if left is less than rhan cighe procedure ShowTable end inttable with text_io use text io package body inttable is procedure MoveIntegers From To natural is begin she TO SS abu Erom end MoveIntegers function CompareIntegers left right natural return boolean is begin return it left lt it right end CompareIntegers procedure ShowTable is begin for i in IntegerTable range loop P t _Line i img amp amp it i img end loop end ShowTable end inttable This is an example of bubble sorting an integer table The table begins as 0 13 2 3 4 16 5 The sorted table is 0 13 v ae file G Linux http www vaxxine com pegasoft people html book 12 html 26 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages So de 4 13 5 16 The heap sort package works identically with both generic heap_sort_g and callback heap_sort_a versions as well Heap sorts are better suited to large amounts of data Here s the callback version using the same inttable package we used above with text_io gnat heap_sort_a p use text_io p procedure heaptest is begin Put_Line This is an example of heap sorting an integer table New_Line P
87. The easiest though not necessarily most practical way to do Linux programming is to use the standard C library s system call System starts a new process starts a shell running and gives the shell whatever command to execute that you specify The command executes just as if you typed it in at the command prompt For example to list the files in the current directory on the screen you d type function sys pragma Impor cmd string returns integer C system em Result system Is amp ASCII NUL The result is the exit status returned by the command usually zero if it executed successfully or non zero if there was an error To capture the output of the system command you can redirect the results to a file using the shell s output redirect gt This creates a text file for you to open with Ada Text_IO Open Result system ls gt tmp ls out amp ASCII NUL Ada Text 1O O0pen fd an file ctme ls out The following is a simple program to print to the printer with the Text_IO library It creates a text file and then uses system to run lpr to print it with Ada Text IO use Ada Text IO procedure printer is a program for simple printing function System s string return integer pragma import C System system starts a shell and runs a Linux command procedure PrintFile s string is run the lpr command Result integer begin Result System lpr a
88. To meet this goal it uses a number of interesting features e addd style debugger e automatic saving whenever you open a new source file tia saves your old file e quiet updates each time a file is saved TIA will attempt to recompile the file to reduce the project rebuilding time file G Linux http www vaxxine com pegasoft people html book 3 html 1 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s TIA will only update one file at a time to avoid slowing down your machine e automatic spelling correction When you press return enter while editing your source file TIA automatically corrects common spelling mistakes for any of the following words or phrases procedure function package exception subtype end if end loop end record e error hilighting you can move between compiler errors with a single keypress and the cursor is automatically positioned at the exact location of the error and the message displayed at the bottom of the window e quick open you can open recently opened files with a single keypress e tight integration with gnat for example you can load a package spec and create a body using gnatstub by simply selecting Stub in the File menu e support for keyboard macros If you are interested in an X Windows IDE you should read the next section on GRASP 3 1 1 Quick Start Before you compile a program you have to set up the project parameters u
89. a conceptually combination of lists and bags Duplicates actually exist as copies in the collection not simply counted Collections are also indexed like a list so that items can be referenced in the collection The Collections package provides the following subprograms Create Create a new collection and its initial chunk Clear Remove all items from a collection Insert Add an item in front of another Append Add an item to the end of the collection Remove Remove an item at an index Replace Replace an item at an index Length Return the number of items in the collection Is_Empty True if there are no items in the collection First Return the item at the front of the collection Last Return the item at the end of the collection Item_At Return the item at a particular index Location Return the first index where an item is found 0 if Collections are implemented as dynamically allocated arrays with BC Containers Collections Dynamic with Global_Heap package products is type aProduct is record id integer weight float end record package productContainers is new BC Containers Item gt aProduct ens is the base container package productCollections is new productContainers Collections create a new collection support for our using container type package productCollection is new productCollections dynamic Storage Manager gt Global Heap Pool Storage
90. a company that uses more than arrays this chapter will discuss how to use other kinds of data structures in Ada 18 1 Using the Booch Components Like Ada C has no advanced data structures built into the language To provide a standard set of data structures what is now called the Standard Template Library was developed to provide the tools necessary to organize most types of data Perhaps because of an oversight Ada 95 with all its annexes has no equivalent to the C Standard Template Library There are no standard packages providing common data structures The Gnat compiler fills part of this void with packages for creating simple tables and hash tables The Booch components are a set of C objects created by Grady Booch These were later ported to Ada 95 The components contain sets of general purpose data structures The Booch components are available from AdaPower Net or in RPM format from the Ada Linux Team This is one popular choice for Ada s unofficial Standard Template Library The components are organized into three main categories tools support and structs The tools cover many items already implemented in the standard Ada or Gnat packages such as searching sorting and pattern recognition Support refers to components that implement the tools and structs The structs data structures are the primary interest of Ada programmers These are further subcategorized by the user s requirements bounded where the size
91. a finali Ada Finalization pne Ed tagged record package a flteio Ada Float Text IO Instantiated Text_IO for floats b fvteo t Float_WideText 10 fe WE oe floats inti Ada Integer Text 10 a a integers bcn Adalintermipe ee Ada signal handling package a intnam Ada Interrupts N ames Linux signal names poezo Ada 10 Exception H ezer piicns ured au ste packages bciwei da Ineger Wide Text IO mom Wide Text FOE integers b ifteio Ada Long_ Float Text 10 1E Text TO for TONE floats a lfwtio Ada Long_Float_Wide_Text_IO Tastantiated Wide Text TO for B floats iti t Long Integer Text 10 Eom Tert IO for done integers stint Ada Long_Integer Wide Text IO Eure Wide Text IO Tor ong integers tio ta Long Long Float Tex 10 nu Text TO for long ong floats pwi Ada Long Long Float Wide Text IO E Wades Sex for loig ong floats elo Ada Long Long Ineger Text 10 Fe Tex IO ior long long integers om Ada Long Long Integer Wide Text 10 fos Wide_Text_10 for long long integers Inst of std ops for complex a ncelfu Ada Numerics Complex Elementary Function PU bongoeh t Numerics Generic Complex Elementary Function bum uL for complex nbrs bongcon Ada Numerics Generic Complex Types Pons complex minbars package eng Ada Numerics Generie_Blementary Functions ae SW Ops Tor gomplex numbers file G Linux http www vaxxine com pegasoft people html book 99_f html 2 of 9 7 20 2001 11 40 56 AM Big Online Book of Linux Ada Programmin
92. a list of C strings function getgid return integer pragma import C getgid Get the real UID of the process Example Put Line My GID is amp getgid img function setguid gid integer return integer pragma import C setgid Change the effective GID and saved and real of a process to a new group Linux also allows you to arrange processes into groups for easier management of multiple processes at once Each process group as a no surprise a process group identification number PGID function setpgid pid pgid integer return integer pragma import C setpgid Place a process into a new process group PID 0 is the current process PGID 0 creates a new process group function getpgid pid intger return integer pragma import C getpgid Example Put Line My PGID is amp getpgid img Returns the process group number for a process PID 0 is the current process Every program and process group also belongs to a session as in a login session When you log off the computer Linux automatically stops all programs that were running in your session The session leader is the top process in a session such as your login shell However if you want to create a new session for some reason you can use the following function function setsid return integer pragma import C setsid Start a new session and return a new session identification number SID Example NewSID etsid 16
93. accessibility warning Spawn Ls Arguments WasSpawned if WasSpawned then New Line Put Line End of ls output Spawned worked else Put Line Spawn failed end if This fragment runs the Is command prints the results on the screen and then displays the success of the command on the screen Notice there are differences between spawn and system e spawn only gives you a boolean result e spawn does not start a shell so it is more secure e because there is no shell you can t run built in shell commands nor can you redirect output using gt If spawn is too limited many UNIX and Linux programming books tell you how to create your own spawn style subprograms using fork wait and the exec family of standard C commands Here is an example of a short C function that executes a program and puts the results standard output and standard error to a text file of your choosing allowing up to three parameters for the command ine CR unite char path Char outfile charn S parami char param2 Char paramo nl pid_t child iae EAO Edin E2 int status lnt s Xf Cehild fork 9 Redirect stdin out err for i 0 1 lt FOPEN MAX i close i fd0 open dev null O RDONLY if fd0 lt 0 exit 110 tdi open outei le OLNRONEY T OSC SEAT Ol TRUNG iE dalL lt 0 exit ri J td2 dup l5 if param1 0 2 PO d execlp path pa
94. any version of UNIX It is possible to use autoconf and automake on Ada Makefiles but this topic is beyond the scope of this book More information on automake and autoconf can be found using info autoconf and info automake The following is an example of what happens when you run an autoconf configure script as run for the FreeAmp program checking host system type i686 pc linux checking for a BSD compatable install cached usr bin msta l MGE checking whether build environment is sane yes checking whether make sets MAKE cached yes checking for working aclocal found checking for working autoconf found checking for working automake found checking for working autoheader found checking for working makeinfo found checking whether make sets MAKE yes CNecking wor Gee dee checking whether the C compiler gcc works yes checking whether the C compiler gcc is a cross compiler no checking whether we are using GNU C yes checking whether gcc accepts g yes checking for Cth CH checking whether the C compiler c works yes checking whether the C compiler c is a cross compiler no checking whether we are using GNU C yes checking whether c accepts g yes file G Linux http www vaxxine com pegasoft people html book 5 html 5 of 6 7 20 2001 11 31 40 AM Big Online Book of Linux Ada Programming 5 Building Large Projects checking checkin
95. apples and peaches Put_Line Set 2 has apples peaches and pears New_Line Put_Line Extent of set 1 6 Extent s1 img Put_Line Extent of set 2 amp Extent s2 img Put_Line Peaches in set 1 amp Is_Member sl peaches img Put_Line Pears in set 1 amp Is Member sl pears img P t Line Set 1 a subset ot set 22 s T3 Subset sl s2 amg Put_Line Set 2 a subset ot set 1 amp Is_Subset s2 s1 amg Put_Line Set 1 a subset of set 1 amp Is Subset sl sl img Put Line Set 1 a proper subset of set 1 amp Is Proper Subset sl sl img New Line s3 sl Union SS SA Pucar rine seu o as the unon or See Wand see 2 Put Line Extent of set 3 amp Extent s3 img end set demo This is a demo of the Booch components sets Set 1 has apples and peaches 2 has apples peaches and pears xtent of set 1 2 tent of set 2 3 Ed Eu Peaches in set 1 TRUE Pears in set 1 FALSE Set 1 a subset of set 2 TRUE Set 2 a subset of set 1 FALSE Set 1a subset of set 1 TRUE Set a proper subset of set 1 FALSE Set 3 is the union of set 1 and set 2 xtent of set 3 3 ea file G Linux http www vaxxine com pegasoft people html book 18 html 12 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures 18 1 7 Collections Collections are
96. array or until a terminator is found It can also slice a specific number of elements from an array Copy Array copies a slice of a specific number of elements from one pointer to another Copy Terminated Array copies a slice from the pointer position until a terminator is found The following program demonstrates C pointers to integer arrays with Ada Text IO Interfaces C Pointers use Ada Text IO procedure point is To use Interfaces C Pointers you need to define an unbounded array type In this case we ll create an unbounded array called IntegerArrays with a maximum index range of 1 to 9 BiggestArray is the largest IntegerArrays array possible with an index range of 1 to 9 IntegerArrays must have aliased elements because we will be accessing them with an dee ENIOGS s subtype PointerRange is integer range 1 9 type IntegerArrays is array PointerRange range lt gt of aliased integer file G Linux http www vaxxine com pegasoft people html book 17 html 3 of 11 7 20 2001 11 37 38 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada type BiggestArray is new IntegerArrays PointerRange package IntPtrs is new Interfaces C Pointers Index gt PointerRange the index range Element gt Integer what the array contains Element Array gt IntegerArrays the unbounded type Default Terminator gt 0
97. at once ip integerPtr new Integer 5 To create a record with a pointer to itself have an empty type statement with the record first type LinkedListRecord type LinkedListPtr is access LinkedListRecorg type LinkedListRecord is record IEOR ehe meteo pi 1b 910b F next Pinkedli StB end record To point to variables you ve declared you must declare those variables as aliased to indicate they can be pointed to To get the address of something use the access attribute type CustomerArray is array 1 100 of CustomerRecord type CustomerArrayPtr is access all CustomerArray ca aliased CustomerArray cp CustomerArrayPtr ca access cp now points to ca Individual array elements can also be aliased file G Linux http www vaxxine com pegasoft people html book 11 html 15 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming type CustomerArray is array 1 100 of aliased CustomerRecord type CustomerArrayPtr is access all CustomerArray cak CUS EOMErArray el5p C ustomerArrayPtr Ga ls cess Ada will give you an error when you try to use access when the object pointing to may disappear after the pointer does If you re absolutely certain that this won t happen you can circumvent the error by using unchecked_access An access type is necessarily just the address of a dynamic object To get the address of an access type it s best to use gnat s g
98. code 1 Spd salesman code 1 error not allocated exception when System Debug Pools Accessing Not Allocated Storage gt Put Line Accessing Not Allocated Storage raised when others gt Put Line Unexpected exception raise end New Line Debug Pool Exception 2 begin Put Line Freeing a non allocated access type is an exception Put Line spd2 sr access not allocated in pool j Put Line Free spd2 Spd2 sr access Free spd2 exception when System Debug Pools Freeing Not Allocated Storage gt Put Line Freeing Not Allocated Storage raised when others gt Put Line Unexpected exception raise end New Line spd new Sales Record salesman code gt 1 sales amount gt 55 50 Debug Pool Exception 3 begin Put Line Accessing deallocated access type is an exception Put Line spd new Sales Record Put Line Free spd Put Line spd salesman code 1 Free spd Spd salesman code 1 error not allocated file G Linux http www vaxxine com pegasoft people html book 11 html 18 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming exception when System Debug_Pools Accessing_Not_Allocated_Storage gt Put_Line Accessing_Deallocated_Storage raised when others gt Put Line Unexpected exception
99. common error subtype mark required in this context indicates that there are several different types that could be used and you have to indicate to the compiler which should used 10 7 1 Modular Types Normally if a calculation produces an answer too large for the variable type being assigned to it creates an error This is called a numeric overflow For example if int is an integer int integer max 1 check KB will result in a constraint error because the answer is bigger than the biggest number an integer variable can contain Ada provides another type of integer called a modular type The word modular comes from the mathematical modulus operation Modular types never overflow Instead if a number becomes bigger than the largest possible number the variable can contain the value of the modular type wraps around to the lowest value and continues to grow from there If the int variable in the above example was a modular called int modular then int intmodular max 1 would result in int being assigned intmodular min C C integer types are all modular because C doesn t catch overflow errors There are no built in modular types All modular types are new types created by a type statement type modl10 is mod 10 value ranges from 0 to 9 file G Linux http www vaxxine com pegasoft people html book 10 html 19 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada
100. file get a stream representing the file s contents while not End of File stream file loop declare contact contact inio class contact nro class ITEM S ln We stream file G Linux http www vaxxine com pegasoft people html book 11 html 28 of 39 7 20 2001 11 33 47 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming begin if this were more sophisticated we could write a Put procedure for each tagged record and use dynamic dispatching if contact in phone number then Put Line read a phone number elsif contact in office number then Put Line read an office number else Put Line read something else end if end end loop Close stream file close the stream file end class stream An example of Ada Streams Stream IO and a Class Created a stream file Wrote a phone number Wrote an office number Opened a stream file read a phone number read an office number Files of items of the same time are more easily created with Ada Sequential IO or Ada Direct IO Custom streams can be created to save or trasmit data in other ways such as in memory or through a network connection Custom streams are created as tagged records extended from a root class Ada Streams Root Stream Type class type My Stream is new Root Stream Type with record Your stream type must override the abs
101. gnat os_lib library is an example of a thick binding to basic Linux file operations When installing binding libraries e Make sure that the filename endings are the right ones for gnat Different compilers use different conventions e Compile the binding package s e Install the library the binding is for if necessary e Include Iname on the link line where name is the library Remember that the order of the l s is important 14 3 Catching Linux Signals A programs has to be able to respond to unexpected events What do you do when somebody types control C How do you gracefully stop the program when somebody kills it with the kill command These unexpected events are referred to a signals in Linux and Gnat provides libraries for you to catch these signals and respond to them gracefully The standard Ada 95 package Ada Interrupts and its children handle unexpected operating system events Under Linux these packages provide support for signal handling A complete list of Linux signals is listed in an appendix The package Ada Interrupt Names defines the names of these signals for you Signal Handlers are protected type procedures with no parameters The body of the procedure performs whatever actions you want to do when you receive a signal For example to catch the SIGTERM signal the signal that indicates that the program has been killed with the kill shell command you can write a handler like this protectedbodySignal
102. grasp amp to start GRASP GRASP provides online help Extensive documentation is provided in HTML format but it s not lynx browser friendly You ll have to use a GUI browser like Netscape 3 2 2 Quick Start Open a new source window using File Ada 95 Type in your program Save the source file as testl adb Add testl adb to your project by chosing File Add to Project If you are using ALT gnat change the compiler configuration under Compiler Command Setup Un A U Ne 6 1 Select Compiler Command Setup You ll see the list of commands Grasp uses to invoke gnat 2 Change the Compile and Check commands from gcc to gnatgcc the name used by ALT 7 Compile the program by chosing Compiler Compile and Link If there were no errors the message window will appear with the message Grasp operation completed and no error messages above it 3 2 3 The Project Window The first window that appears is the GRASP project window It contains the word GRASP but as you add source files to your project they will be added to this window The File Menu Ada 95 et al opens a new source file window Choose a language Ada 95 C C Java or VHDL Save all files saves all open files Exit GRASP quits GRASP closes all open windows The Project Menu New start a new project Open open an exisiting project Close close current project Save save current project Create Save as save cur
103. html book 12 html 23 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages use text io procedure bubblel is Q r table Co sort type IntegerTable is array 0 5 of integer nim eser delle 0 13 4 5 I6 9 J Define the items required by a generic gnat bubble sort procedure MoveIntegers From To natural is begin die To 2S It From end MoveIntegers function CompareIntegers left right natural return boolean is begin return it left lt it right end CompareIntegers OK instantiate the package package IntSort is new gnat bubble sort g Move MoveIntegers how to move two things Lt CompareIntegers how to compare to things procedure ShowTable is begin for i in IntegerTable range loop ibl balia C ab Valley SY T amp cabe o i J img l end loop end ShowTable begin Put Line This is an example of bubble sorting an integer table New Line Put_Line The table begins ase ShowTable Intoort sort it last jJ sort elements 1 to top of it array New_Line P t _Line The sorted taole is J ShowTable end bubblel This is an example of bubble sorting an integer table The table begins as file G Linux http www vaxxine com pegasoft people html book 12 html 24 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages
104. http ada95 freeservers com index html 3 3 2 Jessie Jessie is an X Windows IDE for building large projects and designing multiple executables at once It s an open source project of Silicon Graphics http www sgi com and works with multiple languages ACT has announced that Gnat will provide Jessie support in the future Jessie is downloadable from http oss sgi com file G Linux http www vaxxine com pegasoft people html book 3 html 9 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s 3 3 3 Rapid RAPID is an X Windows GUI Builder that works with TASH the Ada TCL TK package You can draw TCL TK windows containing Labels Text Buttons Radio Buttons Check Boxes and other widgets When you select Compile RAPID saves the Ada source code necessary to display using TASH the window you drew RAPID is available from ALT 3 3 4 VIDE VIDE is a C C Java IDE but it will work with Gnat if configured correctly However it doesn t support Ada keyword hilighting HVIDE 1 04 18Nov99 File Edit Project Build Tools Options Help Window olsa mirii geil Debug ini make clean f C vi vide rm f mygapp o myc this my pp 8x420888 win CvWindow 8x8 make f ore ro d ume 80x48133e My V App gt gt g Ic mingw32 iniw 8 gt gt 9 Ic mingw32 inih 8 gt gtt o my exe myopwinInfo vAppWinInfo 0x8
105. in out Memory Buffer Write Buf Read Buf Rewind_Rea out Stream out Stream in out Memory Bu in El jl us Po fer er out Memory_Buff emeente Se ement_Offset T E in out Memory B Item Rewind Write Buf in out Memory Bu Max Elem in Stream file G Linux http www vaxxine com pegasoft people html book 1 1 html 30 of 39 7 20 2001 11 33 47 AM out Stream Element Offset is new Controlled with record Element Array Big Online Book of Linux Ada Programming 11 Advanced Ada Programming end Memory_Stream Id memory stream adb v 1 1 2000 11 26 05 00 18 wwg Exp c Warren W Gay VE3WWG ve3wwg home com ve3wwg yahoo com Protected under the GNU GPL License with Ada Text IO use Ada Text IO with Ada Finalization use Ada Finalization with Ada IO Exceptions use Ada IO Exceptions with Ada Unchecked Deallocation package body Memory Stream is procedure Read Stream in out Memory Buffer Stream Item out Stream Element Array Last out Stream Element Offset is begin Read Stream Mem Buf Item Last end Read procedure Write Stream in out Memory Buffer Stream Item in Stream Element Array is begin Write Stream Mem_Buf Item end Write procedure Rewind_Read Strea
106. include asm linux h For each ioctl I list its numerical value its name and its eius reise es An argument type of const struct foo means the argument is input to the kernel struct foo means the kernel outputs the argument If the kernel uses the argument for both input and output this is marked with I O Some ioctls take more arguments or return more values than a single structure These are marked MORE and documented further in a separate section This list is incomplete It does not include Ioctls defined internal to the kernel scsi ioctl h Ioctls defined in modules distributed separately from the kernel And of course it may have errors and omissions Main table lt include asm i386 socket h gt 0x00008901 FIOSEIOWN const int Ox00008902 SIOCSPGRP const int 0x00008903 FIOGETOWN int 0x00008904 SIOCGPGRP int 0x00008905 SIOCATMARK int 0x00008906 SIOCGSTAMP timeval file G Linux http www vaxxine com pegasoft people html book 99_e html 1 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E include asm i386 termios h 0x00005401 0x00005402 0x00005403 0x00005404 0x00005405 0x00005406 0x00005407 0x00005408 0x00005409 0x0000540A 0x0000540B 0x0000540C 0x0000540D 0x0000540E 0x0000540F 0x00005410 0x00005411 0x00005412 0x00005413 0x00005414 0x00005415 0x00005416 0x00005417 0x00005418 0x00005419 0x000054
107. info acm org sigada W G asiswg asiswg html Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 19 html 4 of 4 7 20 2001 11 38 32 AM Big Online Book of Linux Ada Programming 20 Developing Your Project 20 Developing Your Project lt Last Chapter Table of Contents Appendices gt 20 1 The Project Proposal Before you begin any project that will be released to the public it s a good idea to draw up a proposal The proposal should be about one page document describing the purpose of the project who it s being made for and how long it will take and what kind of investments time money or otherwise you expect This is especially important if there is anybody working with you Don t assume your teammates see the project in exactly the same was as you do write a proposal to avoid misunderstandings For example calling a project a database doesn t say much Calling it a fast distributed database for businesses tells your teammates where the database will be used gives them an idea about the features required and tells that the design emphasis is on execution speed Once your proposal is finished bounce the ideas of a few people you respect and trust especially if they are potential users of your program If none of them think the project is practical you may want to change the target audience or features of your project or chose another project altogether
108. information in this document may be obsolete or to paraphrase Douglas Adams apocryphal or wildly inaccurate However most of the facts have been verified against Gnat 3 11 or a later version and most of the examples in this document have been compiled under Gnat Ken O Burtch September 1999 file G Linux http www vaxxine com pegasoft people html book 0 ii pref html 7 20 2001 11 28 01 AM Big Online Book of Linux Ada Programming 1 Introduction 1 Introduction Table of Contents Next Chapter gt Rewrite amp Expand Ada 95 is arguably the most powerful development language available for Linux with features comparable to Java and execution speeds similar to and sometimes exceeding C gnat the main perhaps only check at HBAP KB Ada 95 compiler for Linux is also absolutely free This makes a combination that s hard for Linux programmers to ignore 1 1 A Brief History of Linux The Linux operating system that was created as a hobby by a young student Linus Torvalds at the University of Helsinki in Finland Linus interested in the UNIX clone operating system Minix wanted to create an expanded version of Minix with more capabilities He began his work in 1991 when he released version 0 02 and invited programmers to participate in his project Version 1 0 was released in 1994 The latest version is 2 4 and development continues Linux uses GNU General Public License GPL and its source code is freely available to ever
109. is a e i o u none characters may be used as well as identifiers The standard character sets are implemented this way type aDogBreed is Jack Russel Labrador German Shepherd Other type aCanadianRegion is West Coast Arctic Labrador Other subtype coldPlaces is aCanadianRegion range Arctic Other names may overlap between enumerated types type anErrorCode is None IOerror for anErrorCode use None gt 0 IOerror gt 7 specific values may be assigned to enumerated identifiers function toInteger is new unchecked conversion anErrorCode integer begin Basic enumerated type operations put The vowel u has a position of put integer image vowels pos u p t line YV imn the list EI put The vowel after a is put vowels image vowels succ a put bine ts Using a regular enumerated Where an identifer belongs to two enumerated types we have to apply a type qualifier when ambiguity comes up put The item before German Shepherd is put aDogBreed image aDogBreed pred German Shepherd p t_ line e put The item after Labrador the region is put aCanadianRegion image aCanadianRegion succ Labrador p t_ line T J put line Listing of cold regions between Labrador and Other for cr in coldPlaces Labrador other loop put line aCanadianRegion image cr end lo
110. is a note to the reader Ada will ignore it Everything you type to the right of the symbol is treated as a remark to the reader C Ada has no equivalent to the block comment and 10 2 Text IO Ada Description CC Equivalent put si Display a string printf 5 s put n img Display a number sprint f sda nO put_line s Display a line of text and start anew line printf s n s new_line Startanewline printf iio er get c Read a character from the keyboard c getc get line s len Read a line of text from the keyboard gets amp S etc Like many modern computer languages Ada doesn t have any built in methods of reading the keyboard or writing messages on the screen It doesn t assume you re writing a program for a PC you could be doing embedded programming for example but in general you need to interpret what people type and display the results to the screen You have to add this functionality specifically The standard input output package for Ada is Text_IO This package prints characters and strings to the screen and reads characters and strings from the keyboard It can also read and write simple sequential text files Packages will be discussed in detail starting at 11 1 in the next chapter Text_IO is only useful for simple programs It doesn t have the ability to draw buttons windows or menus For X Windows programming you ll require other
111. is finished In out means the value goes into the subprogram is changed and is returned again when the subprogram is finished In Ada functions can only have in parameters but procedures can have all three procedure AddOne x in out integer is begin XG Sa cuti end AddOne AddOne Subtotal C There is no equivalent of pass by copy or pass by reference See the section on interfacing C and Ada There is also a special access mode which means that the parameter must be an access variable This is especially useful with tagged records You can also get around the in out restriction on functions with the access mode It is discussed in 11 10 2 C An access variable is basically a pointer These are described later An example of multiple parameters procedure DisplayCurrency c aCurrency fieldWidth integer useDollarSign boolean true is useDollarSign the third parameter has a default value of true Here s now you can call this procedure DisplayCurrency 1 97 8 file G Linux http www vaxxine com pegasoft people html book 10 html 25 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada DisplayCurrency 1 97 8 false DisplayCurrency 1 97 8 useDollarSign gt false DisplayCurrency c gt 1 97 fieldWidth gt 8 useDollarSign gt false If you really wanted to you can also change the order of the parameters using the
112. like a Text IO file Dir Type is a limited private directory type corresponds to a file type in Text IO Directories can only be read Open Open a directory for reading Close Close a directory e e Read Read a directory entry When a null string is returned there are no more entries e Is Open True if the directory is open e Read Is Thread Safe True if the directory can be read by separate tasks threads That is if there is a readdir_r kernel call Any error will raise a DIRECTORY ERROR exception with ada text io gnat directory operations use ada text io gnat directory operations procedure gdir2 is dar Dir Type dirname String i 5 len natural begin if Read Is Thread Safe then put line Tasks may read the same directory else put line Tasks may not read the same directory end if New Line Open dir uu ys if Is Open dir then put Line The directory was opened else put Line The directory was not opened end if loop Read dir dirname len exit when len 0 Pute Linel dirname d bemnm 95 end loop file G Linux http www vaxxine com pegasoft people html book 14 html 13 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming put bine C End ot directory J Close dir end gdir2 Tasks may not read the same directory The directory was opened gdi rr ads gdir ali gdir adb Cd 20 gair Gour2
113. lists with assignment statements because it s limited private C In C privacy is limited to classes In Ada virtually anything can be private Packages can have children A child package is a package that extends the capabilities of the parent package You can use child packages to add features to existing packages such as the standard Ada libraries or to break up large packages into groups of related functions Suppose you had a package called accounting that contains tools to handle accounting in general You can create a child package for accounts payable begins like this package Accouting Accounts Payable is In GNAT save this package spec as accounting accounts payable ads with a minus sign instead of a period file G Linux http www vaxxine com pegasoft people html book 11 html 3 of 39 7 20 2001 11 33 44 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming A child package inherits the package spec from it s parent package You can access anything in the accounting package including anything private to which access is normally denied When a program uses the statement with Accouting Accounts_Payable the parent package accounting is automatically with ed as well although you still have to use separate use s 11 2 Controlling Elaboration Ada Pragma Description C Equivalent pragma Pure The simplest kind of package When an entire package isn t pragma Pure Function function
114. made changes to one of the Ada files you ve been working on CVS will attempt to update your copy without destroying your work file G Linux http www vaxxine com pegasoft people html book 9 html 4 of 6 7 20 2001 11 32 37 AM Big Online Book of Linux Ada Programming 9 Team Development Sometimes the changes involve the same part of the Ada file and CVS won t be able to combine the changes automatically CVS calls this a conflict For example suppose your Ada file contained a function function ConvertCurrency amount integer return float If you changed this function to use a float amount and another team member has changed amount to a string CVS will report a conflict You will have to talk to the team member who made the change and make an agreement what amount should be If there are no other problems after an update you can continue working on your source code To delete a file remove it using rm and then update CVS will see your file is no longer in the project The CVS command release will permanently remove a file from a project including the copy in CVSROOT but it also prevents you from recovering the file from the CVSROOT directory in an emergency Unless storage space is limited consider using the rm update method of removing files While working on your source code your changes are not distributed to the rest of your team until you are ready When your source code is t
115. message remain unchanged file G Linux http www vaxxine com pegasoft people html book 10 html 8 of 29 7 20 2001 11 33 06 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada with Ada Text IO use Ada Text IO procedure basicio3 is this program demonstrates more even advanced input output i integer 5 this variable contains an integer number i initially has the value of 5 sS s string I 5 this Variable contains a 5 character Ste len natural length of string begin Put Line This program displays information on the screen Put Line and reads information from the keyboard New Line Put Line The value i is amp i img New Line Put Line integer value changes a string into an integer value Put Line Type in a 4 character integer characters with a leading Put Line space or negative sign and press Enter Get Line s len i integer value s Put Line The value of i is amp i img New Line end basicio3 This program displays information on the screen and reads information from the keyboard The value i is 5 integer value changes a string into an integer value Type ina 4 character integer characters with a leading Space or negative sign and press Enter 2345 The value of i is 2345 file G Linux http www vaxxine com pegasoft people html book 10 html 9 of 29 7 20 2001 11 33 06 AM Bi
116. name pure A package with simple pragma Preelaborate Sor pragma No Elaboration Code Similar to Preelaborate to Preelaborate B Force EM to be a pragma Elaborate package first if possible E TER Elaborate the body before the pragma Elaborate Body package specification E Short for Elaborate for each pragma Elaborate All package Elaboration is the initialization of a package that s done before the main program of the package is executed Assigning values to constants for example is elaboration C Since C is a has no packages the order of elaboration between files is determined strictly by the compilation order For most projects gnat will work out a good elaboration order on its own However large projects with packages referring to each other in complicated ways may require complex elaboration orders gnat searches every possible elaboration order until it finds one that solves any ambiguities To speed up projects with slow elaboration times Ada and gnat provide a number of pragmas to give the compiler hints on the best compilation order and to solve any potential ambiguities 11 2 1 First line of defense Pure Preelaborate and No Elaboration Code Pragma Pure and Preelaborate are elaboration restrictions They are hints to the Ada compiler to cut down the compiler s work when trying to solve elaboration order Pragma Pure tells Ada that the packa
117. of 35 7 20 2001 11 34 28 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages procedure exc is e exception saved exception Exception Occurrence procedure CrashMe is begin Raise Exception e identity call exec development team end CrashMe begin Put Line This is an example of the Ada Exceptions package New Line Information about an exception that is not in progress Put Line Exception Name returns a unique name for an exception Put Line The unique name our exception is amp Exception Name e identity New Line Raising an exception with a message Put Line raise will raise an exception with no message New Line Put Line Raise Exception will raise an exception with a message Put Line Raising amp Exception Name e identity amp with the message call exc development team Put_Line in the subprogram CrashMe 5 New_Line CrashMe exception when occurrence others gt Information about an exception that is is in progress Put_Line my Put_Line An exception has been raised Now in exception handler Put_Line The name of the exception is amp Exception_Name occurrence New_Line Put_Line Exception_Message returns the message for this exception Put_Line The message for this exception is amp Exception_Message occurrence Ge New_Li
118. of 4 7 20 2001 11 30 05 AM Big Online Book of Linux Ada Programming 2 Installing Gnat on Linux The latest public version from ACT is 3 13p which has been compiled for gcc 2 8 1 By default Gnat is installed in a usr gnat subdirectory If you don t have gcc 2 8 1 you can specify a separate directory where gnat will install itself and its own personal copy of gcc 2 8 1 Using this method you need to perform an additional step The installation program doconfig creates a shell script containing environment variables that you can copy to your shell startup script under bash this is usually the profile file in your home directory Gcc uses these variables to locate the gnat files You will need to include the gnat directory in the front of your PATH variable to prevent gnat from using the gcc that came with your Linux distribution For example use the shell command export PATH usr gnat bin SPATH Only use this command when you want to use Gnat since it effectively hides the copy of gcc that came with your distribution If you don t want gnat to be enabled by default you can write a short shell script that assigns the environment variables sets the path and starts a new shell 2 3 Compiling Gnat from its Sources Occasionally you may want to compile Gnat yourself from its sources For example you may want to learn more about computer language design you may want to enable support for other languages e g C e you
119. of Linux Ada Programming 13 Linux Introduction 13 10 Libc5 Libc6 and Upward Compatibility One of the difficulties with Linux programming is that the standard libraries are seldom upwardly compatible For example the ncurses 3 console drawing package is completely incompatible with ncurses 4 Likewise ncurses 4 is completely incompatible with ncurses 5 In an open source enviroment subprogram parameters can appear and disappear with each new release The Gnat compiler always links the standard C library into your programs As a result you have to be aware of the problems with Linux s standard C library even if your Gnat program doesn t call its subprograms explicitly Your Gnat executable always connected to the C library it was compiled against Like most open source libraries the standard C library isn t upwardly compatible Inspite of the fact libc version 5 and libc version 6 now called glibc 2 0 share the same name many functions and names have been changed between the two versions Multithreading under libc5 is done with the linuxthreads library an implementation of pthreads LinuxThreads is based the Posix 1003 1c thread model with a few extensions Linuxthreads is a built in part of libc6 In the Linux world even minor changes between libraries will create problems There is very little upward compatibility For example a program may run on libc 6 0 x but won t run on libc 6 0 y because some symbol names have changed Because
120. out AFileElement count size t pragma import C C Write write pragma import valued procedure C Write Using an in out parameter is the easiest way to pass the address of the data element Because Ada doesn t allow in out parameters in functions we ll use gnat s valued procedure pragma to pretend write is a procedure Our Ada subprograms function Open path string read boolean true return AFileID is open a new file for read or write flags integer begin the flag values are listed in fcntlbits h and man 2 open if read then flags 0 read only existing file else flags 1000 100 1 write only create or truncate end if octal 640 gt usr read write group read others no access return C Open path amp ASCII NUL flags 846404 end Open procedure Close fid AFileID is close a file Result integer we ll ignore it begin Result C Close fid end Close procedure Read fid AFileID data in out AFileElement read one data item from the file BytesRead ssize t begin size returns the size of the type in bits so we divide by 8 for number of bytes to read C Read BytesRead fid data AFileElement size 8 if BytesRead AFileElement size 8 then raise seqio error end if end
121. owing is 2 18500E 03 A null pointer for an access parameter causes an exception Charging interest on a null pointer Constraint error exception raised 11 11 Multithreading Gnat comes with two alternative libraries for multithreading support It can either use the native Linux pthreads built into libc6 or it can use FSU Florida State University threads that are included with gnat By default the Linux version of gnat is compiled for Linux native threads 11 11 1 FSU verses Native Threads The FSU threads provide better concurrency at very small time slices but are incompatible with Linux s pthreads library This means you can t use the FSU version of gnat with the standard Linux libraries unless you recompile the libraries for FSU threads as well FSU threads also force blocking on system calls and can cause blocking problems multiprocessors and as a result most people don t use them One exception is Florist a POSIX that is Linux O S calls binding using FSU threads The main benefit of FSU threads is that they are Ada Annex C amp D compliant To use FSU threads you need to compile gnat from its sources 11 11 2 Tasks In Ada a thread is referred to ask a task It has nothing to do with multitasking as its name might imply A task runs independently of the main program either by true parallelism on a multiprocessor computer or as a separate job on a single processor computer There is no way to sp
122. p ado pali Sead armitage home ken ada test ar t libp a p o armitage home ken ada test gnatmake t lp Strickly speaking lp should use gnatmake s linker options option but this works If the library is in a place other than your current directory you ll need to use the L option to indicate the directory to check A shared library or DLL dynamic link library is a library that is loaded into memory and shared between programs It s not actually saved as part of the executable All Linux shared libraries end in so a shared object archive They are loaded when a program is executed UNTESTED To create a shared library compile the source code with the fPIC position independent code option and link using shared You also need to include W1 soname nameofobject is this necessary under gnat if you use gnatlink I think it probably is see Linux Application programming pg 72 if you forget the fPIC switch your shared library will still load but you won t be able to share the code between applications that use the library fpic will also work on Intel processors because there is no maximum imposed for the global offset table but it may not work on other processors the fPIC switch is the preferred method The shared libraries are usually stored in standard Linux directories like lib or usr lib Once you copy a shared library into one of these directories you have to run ldconfi
123. packages libraries to perform input and output file G Linux http www vaxxine com pegasoft people html book 10 html 2 of 29 7 20 2001 11 33 05 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada C In C printf and company can use an arbitrary number of parameters where the parameters can be of different types Text IO s puts have one parameter and the parameter must be a string or a character Upcoming sections demonstrate how to print other types The most commonly used operations are e Put write to the screen but don t start a new line e Put Line write to the screen and start a new line e New Line start a new line e Get read a character from the keyboard e Get Line read a string from the keyboard The following program is an example of Text IO with Ada Text IO use Ada Text IO procedure basicio is this program demonstrates basic input output c character this is a letter begin Put Line This program displays information on the screen Put Line and reads information from the keyboard New Line Put Line Put Line displays a line of text and advances to BE Put Line the next line Phe e Moso Mr e Put Line displays text but it doesn t start a new line Put Line New Line displays a blank line New Line Put Line Get waits for a character to be typed Put Line Type a key and the Enter key to continue Ge
124. return integer pragma import C shutdown Shuts down one or both directions of a socket This is used for example by web browsers to let the server know there are no more HTTP requests being sent Returns 0 on sucess 1 on failure Example result shutdown mysocket 1 procedure bind result out integer myaddr in out sockaddr addrlen integer pragma import C bind pragma import valued procedure bind Registers your server on a particular port number with the Linux kernel addrlen is the length of myaddr Returns 0 on success on failure Example bind result myservice myservice size 8 function listen socket integer backlog integer return integer pragma import C listen pragma import valued procedure listen Prepares a socket for your server to listen for incoming connections Backlog is the maximum number of established file G Linux http www vaxxine com pegasoft people html book 16 html 38 of 47 7 20 2001 11 37 17 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming connections that can be queued Returns 0 on success 1 on failure Example result listen mysocket 10 procedure accept result out integer socket integer clientaddr in out Sockaddr addrlen in out addrlen pragma import C accept pragma import valued procuedre accept Returns the next connection to your server If there are no connections it w
125. s Day February 14 Washington s Birthday U S February 22 St Patrick s Day March 17 April Fools s Day April 1 Mothers Day second Sunday in May 36 USC Sec 142 Victoria Day Canada second last Monday in May KB Fathers Day third Sunday in June 36 USC Sec 142a file G Linux http www vaxxine com pegasoft people html book 12 html 18 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages e St Jean Baptiste Day Quebec Canada last Saturday in June KB Parents Day fourth Sunday in July 36 USC Sec 142c Grandparents Day Sunday after Labor Day 36 USC Sec 142b Columbus Day U S traditional October 12 United Nations Day U S October 24 Halloween October 31 e e e e e e Boxing Day December 26 The following program demonstrates the basic operations of the calender package with text io calender use calender procedure caldemo is Year Year Number Month Month Number Day Day Number Seconds Day Duration Christmas94 time begin Text IO Put Line A simple calendar example Text IO New Line Solit Clock Year Month Day Seconds J7 Text On Ile Line The current date msi amp Year img amp amp Month img amp amp Day img Text_IO Put_Line It s amp seconds img amp seconds into the day Text IO New Line Christmas94 Time Of 1994 12 25 if Chr
126. set of keyboard macros at startup These must be saved in the SYS directory in a file called macro_file The first letter of each line is the key for the macro and the rest of the line is the expanded macro For example if a line in macro_file contained pPegaSoft Wott then typing control A followed by p would put the word PegaSoft in the input queue as if the person had typed PegaSoft 15 2 11 Appearance and Keys Most of the objects on the screen should be easily understood the majority designed after their GUI counterparts Here is a list e lt gt Text A button Press Return to activate Type the hilighted letter to go immediately to this button e gt Text An menu button Enter Return to activate Type the hilighted letter to immediately activate e Text A radio button Press Return to select this item and deselect the previous item in the group e Text A check box Press Return to switch on or off e H A scroll bar e 50 A thermometer graph Buttons with hyphens in them are not selectable Basic Keyboard Shortcuts Movement Keys Up Down Arrow move up or down to the next menu item in lists move up or down one line in the list file G Linux http www vaxxine com pegasoft people html book 15 html 10 of 13 7 20 2001 11 36 38 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings in scroll bars adjust up or down by 10 Left Right Arrows
127. tail of the string are we get RICH get richer onto happier happier The count of er is 2 There are also a number of libraries dealing with wide strings strings with 16 bit characters If you are only interested in doing case conversions gnat provides a small package called case_util that does case conversions and only case conversions on characters and strings Use case_util to avoid loading the entire Ada Character Handling library The following sample program demonstrates the uses of case_util with text_io gnat case_util use text io procedure casetest is teststr constant string This is a TEST string tempstr ascia ME Mere rS oi begin Put_Line This is an example of the Gnat string case conversion tools New_Line p tt hine a Mines original string is N g tests amp Vuni New_Line Temesige Teste ot Gnat Case_Util To_Upper TempStr Put_Line Upper case is 7 amp TempStr amp s tempstre este a Gnat Case_Util To_Lower TempStr Put_Line Lower case is amp TempStr amp EempStr wees Sites Gnat Case_Util To_Mixed TempStr Pur line Mixed case as s T empStr amp UT file G Linux http www vaxxine com pegasoft people html book 12 html 5 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages end casetest E This is an example of the Gnat string case conversion tools The origin
128. techniques have procedure bench is Simple benchmark program to test optimization pragma optimize time type bench_integer is new long_integer range long_integer range type small_integer is new long_integer range 0 9 function p param bench_integer return bench_integer is divideby constant bench_integer 4 begin return param divideby end p pragma inline p J bench integer bench integer last deliberate error in main program for j 2 type atype is array 0 9 of small integer pragma pack atype file G Linux http www vaxxine com pegasoft people html book 7 html 5 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Programming 7 Optimizing Your Project a s vel ce begin for i in 1 100 000 000 loop j abs p bench integer i J 2 a integer j mod 10 small integer j mod bench integer small integer last end loop end bench Notice that j is assigned the largest bench integer possible This will force an overflow error the first time around the for loop when j is multiplied by two The following chart shows the effect of the different switches and pragmas and indicates when gnat caught the overflow error The test was conducted on a Pentium II 350 with 64 Megs of RAM using the gnat 3 11 NYU binaries and was timed with the time command Gnatmake Switches Pragmas CPU Time Size Error Caught pnumakc gnao gnaE
129. the file The flags are a set of bits with different meanings O RDONLY constant integer 84004 open for reading only O WRONLY constant integer 84014 open for writing only O RDWR constant integer 84024 open for reading and writing O_CREAT constant integer 8 0100 no file create it O EXCL constant integer 8402004 lock file see below O NOCTTY constant integer 804007 if tty don t acquire it file G Linux http www vaxxine com pegasoft people html book 16 html 15 of 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming O_TRUNC constant integer 845010004 file exists truncate it O APPEND constant integer 84020004 file exists move to end O NONBLOCK constant integer 84040004 if pipe don t wait for data QUESYNG constant integer 8 010000 don t cache writes O ASYNC constant integer 840200004 async IO via SIGIO O DIRECT constant integer 840400004 direct disk access O LARGEFILE constant integer 8401000004 not implemented in Linux yet OU DIRECTORY constant integer 8 0200000 error if Tile isn t a dir O_NOFOLLOW constant integer 8 0400000 if sym link open link itself Flags may be added together O_EXCL is somewhat obsolete and has l
130. the terminator value use IntPtrs need this to make and visible procedure ShowArray ia IntegerArrays is show the contents of any IntegerArrays array begin for i in ia first ia last 1 loop Pune d os Uem DRE Put ole Paia al este JE Put end loop P r ale dieere nes atime A Put gt o E Put Line ia ia last img end ShowArray al a ia2 BiggestArray two integer arrays ip ip2 IntPtrs Pointer two pointers to integer arrays begin Put Line This program demonstrates C style pointers provided Put Line by Interfaces C Pointers New Line initialize and display the contents of the array for i in PointerRange first PointerRange last 1 loop tal i J e gs end loop ia PointerRange last 0 Put_Line The array is ShowArray IntegerArrays ia must typecast ia because ShowArray is expecting an IntegerArrays Put Line Zero is our terminator in this example New Line set the pointers to the first elements in the arrays file G Linux http www vaxxine com pegasoft people html book 17 html 4 of 11 7 20 2001 11 37 38 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada ip ia ia first access ip2 ia2 ia first access ip works like a normal access type Put Line Our pointer is set to first position in the ar
131. the timestamp on the file ts File Time Stamp fd GM Split ts Year Month Day Hour Minute Second Put Line The time stamp is amp Year img amp amp Month img amp amp Day img amp Hour amg amp i amp Munute umg amp e amp Second zmg Jj New Line Put Line Writing to the file P t Line EFrirstLine AmountWritten Write fd FirstLine Address FirstLine Length D ut Line Wrote amp AmountWritten img amp bytes Put Line The file length is amp File Length fd img New Line Pa eS GE file G Linux http www vaxxine com pegasoft people html book 14 html 2 of 15 7 20 2001 11 36 18 AM Big Online Book of Linux Ada Programming 14 Linux Programming Treue eX Crossed the file New_Line Put_Line Locating the file we just made sp Locate_Regular_File File_Name gt FilePath Path gt Gethny PATH yas us Put fine The file ws amp sp alle iY js New_Line Put Line Deleting the file Delete File FilePath address WasDeleted if WasDeleted then Put Line File was deleted else Puro Line Hake was not deleted end if New_Line pur rine Running Ie 7 2 ys New_Line Arguments 1 RootDir unchecked access unchecked to avoid unless accessibility warning Spawn Ls Arguments WasSpawned if WasSpawned then New Line Put Line End of ls output Spawned w
132. them and run rpm with the i switch The ALT GNAT build system is available for those wanting to know more about how the RPMs are constructed Using CVS you can check our the source code export CVSROOT pserver anoncvs hornet rus uni stuttgart de var cvs cd SHOME cvs login use empty password cvs z9 co d ALT gnuada alt build 2 2 Installing the ACT Binaries The latest version of the Gnat compiler is available from the ACT FTP site These binaries do not have the extra features available with the ALT RPMs but they include extra installation information including how to install Gnat s various add ons There are also versions for other operating systems besides Linux Gnat 3 12 and older have an additional install option to overwrite you re existing copy of gcc provided it is right version Since it is rare that a distribution has the exact same version of gcc this option is no longer provided ACT will sometimes release several versions of Gnat for different C libraries When downloading the binaries make sure that you download the version compiled against the appropriate C library This is due to the constantly evolving nature of Linux To find out which libc library your distribution uses examine the lib libc so link to find out which file it points to For example if lib libc so points to a libc5 library then you ll need the libc5 version file G Linux http www vaxxine com pegasoft people html book 2 html 2
133. time format you can delay the start of a task with delay until Tomorrow In an emergency one task can terminate another with the abort statement abort CounterTask Ada provides a variation of the select statement for tasks that timeout when they cannot complete their work in time This version has two parts the first part consists of what to do if the task isn t completed in time and the second consists of the task to complete For example if BigCalculation is a slow process that we wish to timeout after 30 seconds select delay 30 0 Put_Line Timeout then abort BigCalculation end select In this example BigCalculation will continue for up to 30 seconds If it doesn t finish Timeout is displayed and BigCalculation is aborted 11 11 3 Task Types Often multithreaded programs will need a set of identical tasks For example you many want to sort a customer s records for several different customers using different threads You can t do this with the simple tasking examples shown so far To create a set of identical tasks you must create a template of the tasks to run Ada calls these templates a task type they look just like a regular task except the specification begins with task type instead of task by itself The following is a task template using the CountingTask example task type CountingTask is entry add amount integer entry currentTotal total out integer end CountingTask T
134. to it later using the seekdir function Info is the C pointer returned by file G Linux http www vaxxine com pegasoft people html book 16 html 21 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming opendir function seekdir info System Address position integer return integer pragma import C seekdir Return to a position in the directory marked by telldir Info is the C pointer returned by opendir function chroot newroot string return int pragma import C chroot Make Linux think that a different directory is the root directory for your program This is used by programs such as FTP servers to prevent uses from trying to access files outside of a designated FTP directory Example Result chroot home server stay in this directory amp ASCII NUL There is also a scandir function that reads a directory and sorts the entries but this is difficult to use directly from Ada The following program demonstrates some of the directory subprograms in Linux with Ada Text IO Interfaces C Ada Strings Fixeg use Ada Text IO Interfaces C Ada Strings Fixed with System Address To Access Conversions procedure direct is Working with directories subtype size t is Interfaces C size t renaming size t to save some typing package CStringPtrs is new System Address To Access Conversions string used innere S Convert between C and
135. user there are usually several programs running in the background The one process that is always running is init this is the root process the first process Linux starts when the system is started 13 1 1 Parents Children and Families Processes are grouped together into families Each time a program starts another process the new process is called a child and the original process is called a parent When the parent unexpectedly stops running Linux knows enough to stop all the related processes as well A multitasking program is a program that starts other processes to run simultaneously and assist it with its work When a child process starts Linux makes a copy of the parent s resources for the child For example all the files that where open to the parent are also open to the child process A multithreading program refers to independent streams of execution within a single process Linux refers to each stream as a thread Ada tasks and protected types for example are threads they do not create entirely new programs they way multitasking works Instead they are miniature programs that run inside the parent task sharing that parent s resources instead of getting their own copy Don t confuse Ada tasks with multitasking the term task was chosen before the term multithreading became popular PID s The ps command shows a list of all processes that are running Each process has its own identifying number called the PID for Proce
136. utimes change access and or modification times of an inode viork alias for fork vhangup virtually hangup the current tty vm86 Intel enter virtual 8086 mode vm86old obsolete wait wait for process termination wait3 wait for process termination BSD style wait4 wait for process termination BSD style waitpid wait for process termination write write to a file descriptor writev read or write a vector Appendix B Table of Contents Appendix D file G Linux http www vaxxine com pegasoft people html book 99_c html 5 of 5 7 20 2001 11 39 50 AM Big Online Book of Linux Ada Programming Appendix D lt Appendix C Table of Contents Appendix E gt Appendix D Signals Be aware that the mapping of names to signals may be to one There may be aliases Also for allsignal names that are not supported on the current systemthe value of the corresponding constant will be zero SIGHUP hangup SIGINT interrupt rubout SIGOUIT quut ASOD FS SIGILL illegal instruction not reset SIGTRAP trace trap not reset SIGIOT II Xpetcuet20 SIGABRT used by abort SIGIOT in the future SIGFPE floating point exception SIGKILE kill cannot be Caught or ignored slGBUS bits error SIGSEGV segmentation violation SIGPIPE write on a pipe with no one to read it SPGALRM alarm clock SIGTERM software termination signal from kill SqGUSET user defined signal 1 SIGUSR
137. we can do simple comparisons the programmer must also specify a procedure to sort the elements by Once you write the package body no generic section in the package body just a regular package body you can instantiate the generic package in a program After instantiation use the package like any other package with SimpleList procedure ListTest is package BooleanList is new SimpleList boolean gt in this case the normal gt will sort booleans begin BooleanList Add mylist true BooleanList Add mylist False end ListTest Now you ll notice that generics and tagged records share a lot of capabilities You can use both to write subprograms that work on a variety of types Tagged records are referred to as dynamic polymorphism because which subprogram to call gets determined while the program is running Generics are referred to as static polymorphism because the subprograms are generated when the generic is instantiated by the compiler and which subprogram to call is known when the program is compiled The better approach depends on what you are doing In general generics run faster but take up more space because the compiler generates separate subprograms for each type Tagged records take up less space but tend to run slower Variant records and tagged records likewise share much in common Although variant records can be simulated with tagged records you ll need to decide which is the best choice
138. with slightly different parameters When multitasking if a child process stops it s retained in memory so that the parent can use wait to find out the reason it stopped running These children are called zombies If the parent process doesn t use wait the zombies will remain indefinitely using up system resources For any large multitasking program make sure you handle SIGCHLD signals these are created when a child stops running The SIGCHLD handler only needs to call wait and Linux will then remove the child process from memory The following is a simple multitasking example that multitasks two Put Line statements a simple example of multitasking that multitasks two put line statements with ada text io use ada text io procedure multitask is type pid t is new integer function fork return pid t pragma import C fork create a new process errno integer pragma import C errno the last error code procedure wait pid out pid t status in out integer pragma import C wait pragma import valued procedure wait wait until all child processes are finished myPID RS pid t wait pid prd t wait_status integer begin Put_Line Welcome to this multitasking example Put_Line This is the original process New_Line the fork function duplicates this program into two identical processes Put Line Splitting into two i
139. wtgeau Ada Wide_Text_IO Generic_Aux Used by wide caracter MO generic packages a wtinau Ada Wide Text IO Integer Aux Internal Use a wtinio Ada Wide Text IO Integer IO Internal Use a wtmoau Ada Wide_Text_IO Modular_Aux Internal Use a wtmoio Ada Wide_Text_IO Modular_IO Internal Use a wttest Ada Wide Text IO Text Streams pon OBI ea E g busora IGNAT Bubble Sort A Bubblesort using access types g busorg IGNAT Bubble Sort G Generic bubblesort Generic bubblesort package Pdlend GNU Calendar Ada Calendar EIU day of week second duration etc Character case conversion penu ONAT Cas Ui Eu Characters Handling Formatted I O for time values g catiio ONAT Calendar Time IO bs Lumcetrt fneo More powerful than g comlin GNAT Command Line Ada Command Line like Linux getopts g curexc GNAT Current Exception pd t M Ada style exception handling file G Linux http www vaxxine com pegasoft people html book 99_f html 6 of 9 7 20 2001 11 40 56 AM Big Online Book of Linux Ada Programming Appendix F Pie pool with allocation Baceppoo ENAT Debu Rooli and dereference error checking g debuti GNAT Debug Utilities Program debugging utilities eg system address output Linux directory changing g dirope GNAT Directory_Operations nn e excep i GNAT Exceptions predefined exceptions for pure packages Set the floating point g flocon GNAT Float_Control processor back to th
140. you For example the Ada compiler is called gnat 1 and the C compiler is called cc1 When gcc detects an Ada source file it runs gnat to compile it Because gcc and Gnat must work as a team specific versions of Gnat are created for specific versions of gcc Gnat 3 10p is compiled against the gcc for kernel 2 0 29 for example the version of gcc used in the Slackware 3 2 distribution Gnat 3 11p 3 12p and 3 13p are compiled against gcc 2 8 1 To find out which version of gcc you have run gcc with the v switch The standard Gnat distribution from ACT comes with its copy of the correct version of gcc and can install Gnat and its gcc in a separate directory The binary versions from ACT s web site have C support removed so if you want gcc to support C and Ada simultaneously you ll have to recompile gcc and Gnat from their sources It is possible to install one version of gcc overtop of another and to select one version or the other using the gcc V switch but gcc must again be recompiled from its newest sources to make it aware of the other version There are patches available via the ALT web site for compiling gnat from the sources for the egcs compiler instead of gcc egcs pronounced eggs is a variation of gcc designed specifically for Pentium computers Egcs is based on gcc 2 8 0 Slackware 3 6 for example used egcs The egcs optimizations are being merged with gcc for the upcoming release of gcc 3 0 ACT has announced p
141. you type cook cook looks for a file called Howto cook This file called a cookbook contains rules or recipes for building a project Each rule has three parts e targets the files built with this rule e g the object file names file G Linux http www vaxxine com pegasoft people html book 5 html 2 of 6 7 20 2001 11 31 40 AM Big Online Book of Linux Ada Programming 5 Building Large Projects e ingredients the files need to do the building e g source code fields e body the commands to do the work these can include other rules Here is an example Howto cook file with one rule main main adb gnatmake main adb The target is main To create main cook must examine main adb If main adb is newer than main cook creates a new main by running the Gnatmake command Cook comes with some predefined rules for compiling certain kinds of files These predefined cookbooks can be attached to your Howto cook file by using include For example Fale lice Me includes basic rules describing the relationships of C files to each other 5 2 1 Cooking in Parallel Cook can use the rsh command to build several parts of a program at once either on a computer with multiple CPU s or over a network If rsh hasn t been configured you ll need to do this before you can run cook For example all the computers should have the source directory mounted via NFS under the same mount directory Also the clocks on all th
142. you typed was Put Line us New Line end unbio This program displays information on the screen EX and reads information rom the keyboard Type in a string Uptown Girl she been looking for a downtown man Put Line displays a line of text and advances to the next line The string you typed was Uptown Girl she been looking for a downtown man For characters the standard Ada library Ada Character Handling provides basic operations such as conversions between case tests for types of characters and conversions two and from 16 bit wide characters Text IO Put Line Ada Character Handling To Upper r This example prints R on the screen For string handling capabilities you need to use a package The standard Ada library Ada Strings Fixed contains operations for fixed strings including extracting substrings mapping characters from one set to another for example upper to lower case and string searching There is also an Ada Strings Unbounded package containing the same subprograms for unbounded strings and likewise an Ada Strings Bounded for bounded strings Figure Standard String Subprograms Append amp concatenate one string to another Element return the character at a particular index Replace Element replace a character at a particular index Slice return a substring Replace Slice Overwrite replace a substring Insert add a string in the midst o
143. 0 0 and ZZ242429 99 gt 0 00 75 12 and AZZ429 99 gt Toei 75 12 and Z22229 99 gt LAYOUT ERROR 0 o 0 enicl 9 99 9 9e gt OOOO Ue Tac I2 cus L999 99 gt Weis IDA Sls ands 9999 99 i 0107 oi 7 OR On Sandi 44 E OO esse O00 75 12 and AS 9O E gt i 2 ub and FAASST LAYOUTL ERROR G20 and 5809 09 0 00 T5 12 and 9959 99 gt S75 12 9 12 amd SS9 99 gt 875 1717 0 0 and 9 99 gt 0 00 75 12 and 44 9 99 gt 975 12 I5 12 amd 9 99 gt S75 12 0 0 and lt 9 99 gt gt S8 810 75 12 and 449 99 gt SOn 75 12 and lt 9 99 gt gt 75 12 Put has many parameters used to override default values e Currency the currency string to use e Fill the fill character to use e Separator the separator character to use e Radix Mark the radix mark to use There is also a Wide Text IO Editing for wide string file G Linux http www vaxxine com pegasoft people html book 12 html 17 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages 12 6 Calendar Package Calendar is the standard Ada package for telling time You can get the current time compare time values do time arithmetic and comparisons There is also a GNAT Calendar package which extends the Ada Caledar package with days of the week second duration and other features Table North American Federal Holidays and Celebrations
144. 001 11 37 39 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada Put_Line Value can also return a slice of a specific length Put_Line The next four elements are ShowArray Value ip Length gt 4 New_Line Copy_Terminated_Array example Put_Line Our second array contains ShowArray IntegerArrays ia2 must typecast here New Line Put Line Copy Terminated Array copies elements from one pointer to Put Line another up to and including the terminator Copying to Put Line the second array Copy Terminated Array ip ip2 ShowArray IntegerArrays ia2 must typecast here New Line Copy Array example Put Line Copy Array copies a specific number of elements Put Line Copying 4 elements from 3 positions ahead the new Put Line array contains Copy Array ipts ip2 4 ShowArray IntegerArrays ia2 must typecast here New_Line end point This program demonstrates C style pointers provided by Interfaces C Pointers The array is gt 2 2 gt 4 3 gt 6 4 gt 8 5 gt 10 6 gt 12 7 gt 14 8 gt 16 Zero is our terminator in this example Our pointer is set to first position in the array The element is 2 Incrementing the pointer it now points at 4 Decrementing the pointer it now points at 2 Addition moves the pointer forward
145. 10 loop IntIO Read id int2read Put Line Number amp i img amp amp int2read img end loop Int rO Close 1d exception when IntIO seqio_error gt Put_line Oh oh seqro error end SegIOtest Note This should be rewritten because a failure to write all the bytes is not necessarily an error Linux has a buffer limit on how much it writes at one time KB file G Linux http www vaxxine com pegasoft people html book 16 html 19 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Writing numbers 1 to 10 to a file Reading numbers back Number 1 1 Number 2 2 Number 3 3 Number 4 4 Number 5 5 Number 6 6 Number 7 7 Number 8 8 Number 9 9 Number 10 10 File Multiplexing Operations These kernel calls help programs that have to monitor several file descriptors at once for activity procedure select result out integer topplusone integer readset in out fdset writeset in out fd set errorset in out fd set timeout in out timeval pragma import C select pragma import valued procedure select Select checks one or more file descriptors to see if they are ready for reading writing or if there is an error It will wait up to timeout microseconds before timing out 0 wll return immediately topplusone is the numerically highest file descriptor to wait on plue one The resul
146. 10 then Put Line I is between 1 and 10 file G Linux http www vaxxine com pegasoft people html book 10 html 17 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada end if 1 10 is called a range The range attribute returns the range of values for a type if salary not in MiddleManagementSalary range then Put_Line The salary is not in the middle management type s range end if C Assignment is considered a statement not an operator 10 6 Variable Declarations You define a variable as the variable name colon the type of information the variable will hold and a semicolon totalSales float This creates a new variable called totalSales that contains a real number Some variations runningTotal integer 0 this variable Starts out at 0 companyName constant string Bob s Widgets Inc companyName is set to Bob s Widgets Inc and it can t be changed while the program is running chari char2 character Complex variables references can be assigned a shorthand with a rename declaration sb float renames EmployeeList CurrentEmployee SalaryInfo Bonus sb 5 0 same as EmployeeList CurrentEmployee SalaryInfo Bonus 5 C There are no self referential operators such as C s 4 10 7 New Types Ada Statement Description lc Equivalent type Create a new type typedef subtype Create a variation of an existing type New types are defi
147. 12 6 gt 14 7 gt 16 8 gt 0 9 gt 134560432 17 4 Interfaces C_Streams package etc Although the basic Ada types are identical to their C counterparts the IO libraries are not guaranteed to write data in a format that is readable from other languages Text files are fine but to write binary files that can be accessed by C you ll need to read and write the files using C file handing libraries The Interfaces C_Streams package provides a thin binding to the C stdio library This is comparable to the gnat os_lib library but the binding is thinner and covers all C stream operations Some stdio library functions aren t covered because they can t be represented by Ada Gnat guarantees these functions will be available no matter what platform gnat is running under even if it isn t UNIX based It is also possible to call stdio directly See the discussion above c_streams uses stream to refer to a Linux text file procedure clearerr stream FILES Clear any error associated with the stream file G Linux http www vaxxine com pegasoft people html book 17 html 7 of 11 7 20 2001 11 37 39 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada function f Close a stream function close stream FILES return int fdopen handle int mode chars return FILEs Open a stream by a handle UNIX file descriptor function eof stream FILEs return int C
148. 1A 0x0000541B 0x0000541B 0x0000541C MORE 0x0000541D 0x0000541E 0x0000541F 0x00005420 0x00005421 0x00005422 0x00005423 0x00005424 0x00005425 0x00005426 0x00005450 mm mm mm mm mm m mm mm m rn a pest esp pea petes ah exp esta Deal a abe al eal elt Dl ioa al te SS Se Soe ete Se Se qe ex CGETS struct termios CSEIS const struct Eermios CSETSW const struct termios CSETSF const Struck termios CGETA struct termio CSETA const struct termio CSETAW const struct termio CSETAF const struct termio CSBRK int CXONC int CELSEH mt LOCEKCL woud IOCNXCL void TOCSCITY aie IOCGPGRP pid t IOCSPGEP const pud E TOCOUTO ant TOUGSTI const char IOCGWINSZ const struct winsize IOCSWINSZ struct winsize IOCMGET int IOCMBIS const int DOCMBIC const aint IOCMSET const int IOCGSOFTCAR int TOCSSOETCAR CONSE IONREAD int TOCING ane TOCLINUX const char Ime Us IOCCONS void IOCGSERIAL struct serial struct IOCSSERIAL const struct serial struct TOCPRTI const int TONBIO const int IOCNOTTY void TOCSEID eonst int IOCGEID int CSERKP int ITOCITYGSIBNUCI Struct tty struct IONCLEX void file G Linux http www vaxxine com pegasoft people html book 99_e html 2 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E 0x00005451 0x00005452 0x00005453 0x00005454 0x00005455 0x00005456 0x00005457 0x000054
149. 2 user defined signal 2 SIGCLD child status change SIGCHLD 4 3BSD s POSIX name for SIGCLD SIGWINCH window size change SIGURG urgent condition on IO channel SIGPOLL pollable event occurred SIGIO input output possible SIGPOLL alias Solaris SIGSTOP stop cannot be caught or ignored SIGISTP user stop requested from tty SIGCONT stopped process has been continued SIGTTIN background tty read attempted SIGTTOU background tty write attempted SIGVTALRM virtual timer expired SIGPROF profiling timer expired SIGXCPU CPU time limit exceeded SIGXFSZ filesize limit exceeded SIGUNUSED unused signal SIGSTIKELT Steck fault on coprocessor SIGLOST Linux alias for SIGIO file G Linux http www vaxxine com pegasoft people html book 99_d html 1 of 2 7 20 2001 11 40 07 AM Big Online Book of Linux Ada Programming Appendix D SIGPWR Power failure lt Appendix C Table of Contents Appendix E gt file G Linux http www vaxxine com pegasoft people html book 99_d html 2 of 2 7 20 2001 11 40 07 AM Big Online Book of Linux Ada Programming Appendix E lt Appendix D Table of Contents Appendix F gt Appendix E loctl parameters man ioctl list gives a list of operations and parameters for ioctl This is a copy of that man page ilg Introduction This xe Loctl nist 1 9 27 a2 l2st ot 2o0 tl calls im Linu i336 kernel 1 3 27 re contains 421 abo ears From usr
150. 32 2 eifixed pointsampls l SND FORMAT DISPLAY jnomaudiodiplaydaa lS SND FORMAT EMPHASIZED J l6 bitlinear with emphasis 19 SND FORMAT COMPRESSED 16 bit linear with compression file G Linux http www vaxxine com pegasoft people html book 16 html 32 of 47 7 20 2001 11 37 16 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming 20 SND FORMAT COMPRESSED EMPHASIZED Combo of the two above 21 SND FORMAT DSP COMMANDS Music Kit DSP commands SamplingRate is the playback rate in hertz CD quality samples are 44100 channelCount is 1 for mono 2 for stereo The info characters are a C null terminated string giving a name for the sound It s always at least 4 characters long even if unused In order to play a sound treat dev dsp as if it were a device attached to your computer for playing au sounds Write a program to open dev dsp for writing and write the au sound to it Playing sounds is a natural candidate for multithreading because you don t want your entire program to stop while a sound is being played The following program uses the seqio generic package we developed above to play an au sound through dev dsp with seqio with Ada Text IO use Ada Text IO procedure playsnd is simple program to play an au sound file package byteio is new seqio short short integer sequential files of bytes au filename constant string beep au s
151. 33 44 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Set the exchange rate between US and Canada and two functions to convert between currencies end Currency In GNAT you must save this package under the filename currency ads ads for Ada Spec Here we create different money values two functions to convert between the different rates and a procedure to set the exchange rates to use in the functions Notice there is no main program With the spec complete you can compile it to check for errors To complete the package we create a package body with the rest of the details including the completed subprograms With the implementation details hidden in the package body other programmers don t have to worry about how currency is actually handled package body Currency is This package defines US and Canadian dollars and converts money between these two countries USToCanadaExchangeRate float CanadaToUSExchangeRate float procedure SetExchangeRates USToCanadian CanadianToUS float is begin USTOCanadaExchangeRate USToCanadian CanadaToUSExchangeRate CanadianToUS end SetExchangeRates function ToCanada money USDollars return CanadianDollars is begin return CanadianDollars money USToCanadaExchangeRate end ToCanada function ToUS money CanadianDollars return USDollars is begin return USDoll
152. 4 2 When you have Too Many Errors When you have so many compiling errors that they run off the top of the screen you can redirect the errors to a file and list them with the less command by adding the following to the end of your compiling command 2 temp out less temp out 4 5 Gnat Binding Options gnatbind checks the integrity of a project before the linking phase You can run gnatbind by itself or have gnatmake run it for you A default generate binder program in Ada See C x aldir besides the directory of the file search for source files in directory dir aOdir besides the directory of the file search for ali files in directory dir b brief messages C generate binder program in C not Ada See A x c check only e list elaboration dependancies E exception stack traceback when compiling with funwind tables f use full reference manual semantics in an attempt to find a legal elaboration order h help Idir combination of aI and aO I don t look for source and ali files in regular places l list the chosen elaboration order mn show no more than m binding errors Mn main program to be called n not the default name n no main program for when the main program is written in another language nostdinc no standard includes ignore default directory when looking for sources nostdlib no standard libraries ignore default directory when looking for libraries 0 file
153. 58 0x00005459 0x0000545A 0x0000545B E EF m m m m e M imnoluds 0x000089E0 0x000089E1 0x000089E2 0x000089E3 0x000089EA4 0x000089E5 0x000089E6 U py 6p UD ODE Op Up IOCLEX T VOIA IOASYNO Const int IOCSERCONFIG void IOCSERGWILD int IOCSERSWILD const int IOCGLOKTRMIOS struct terminos IOCSLCKTRMIOS const struct temios TOCSERGSTRUCT Struct async structs TOCSERGETESR ant TOCSERGETMULIT struct serial multiport struct IOCSERSETMULTI const struct serial multiport struct ixnux sqx253h IOCAXZBSGETULID const Struct sockaddr ax25 LOCAX25ADDULD const Struct sockaddr ax25 IOCAXZ2RDENLUID const struct sockaddr ax295 IOCAX25NOUID const int POCAXZSDIGGIL conse int IOCAX25GETPARMS struct ax25 parms struct I O TOCAXZOSEIPARMS CONSE Struct gx25 parms seEruct include linux cdk h 0x00007314 Silky de TEN AD Mee void 0x00007315 Silla _ BSTART void 0x00 0073 16T STL _BSlOP word 0x00007317 STL BRESET void f f lt iAanclude linux carom h gt 0x0 01005301T 0x 00005302 0x00005303 0x00005304 0x00005305 0x00005306 Qe ele 7 DROMPAUSE void DROMRESUME void DROMPLAYMSF Const struct cdrom msi DROME LAY TRKEIND const SEIS cdrom ti lt DROMREADTOCHDR struct cdrom tochdr DROMREADTOCENTRY struct cdrom tocentry I O file G Linux http www vaxxine com pegasoft people html book 99_e html 3 of 15 7 20 2001 11 40 32 AM
154. 9 7 0 2484 824 R eey 0 00 _ps lfw Here it shows that ps Ifw is a related to the bash shell process but the bash shell is not related to the login command The PPID number shows you which process started another but not which group it belongs to Because the bash shell process and the ps command are both members of the same group if you were to kill the bash process Linux would automatically kill the ps command as well because they are in the same group With this arrangment if the bash shell crashed Linux can return control to the login program and allow you to log in again In the same way if you have many processes in your program you can group your processes so if they crash unexpectedly the main program can continue running and take emergency actions Process groups also provides an easy way to stop several processes at once For example a web server could put all the child processes into one group to make it easy to stop them when the server is being shut down Stopping Processes Normally a process stops when it reaches the end of the instructions it needs to execute You can stop a runaway program or process with the kill command giving the command the PID number returned by the ps command kill 624 killing ps Below we ll discuss stopping processes from inside a program A process that runs continually performing some kind of regular system functions is called a daemon pronounced day mon a variation
155. 9 Software Licensing Options The following is a very simplistic overview of the basic licensing options for Linux Commercial sold for money with warranty Windows 95 is commercial as are most programs that run on it Free Freeware free for all use usually has no warranty GPL GNU Public License free for use and no warranty If it s a programming tool you can only incorporate it into your programs to create more GPL software In other words GPL is free public software that can only be used to make more free public software Imagine a free engine for cars If any car is built to take that free engine it must be sold for free as well LGPL Library GPL same as GPL Commercial programs may only use it if it s shared not statically linked A car can be sold with no engine in it and the engine can be added separately by the dealer but you can t sell the car with the free engine factory installed Shareware commercial software that s sold on the honor system people who like the software and who use it are expected to send in a cheque to the author There s a lot of shareware for Windows XfreeS6 uses a different licence that s compatible with GPL LGPL Virtually all the standard C libraries are LGPL including libc but you should check to documentation or C header files to make sure Details on these and other licensing options and how they interact are described in the book Linux Application Development from Add
156. CM int I O 0xC0044D0B SOUND MIXER WRITE RECLEV int I O OxC0O044DO0C SOUND MIXER WRITE IGAIN int I O OxCO044DOD SOUND MIXER WRITE OGAIN int I O OxC0O044DOE SOUND MIXER WRITE LINE1 int I O OxCO044DOF SOUND MIXER WRITE LINE2 int I O 0xC0044D10 SOUND MIXER WRITE LINE3 int I O 0xC0044D1C SOUND MIXER WRITE MUTE int I O 0xC0044D1D SOUND MIXER WRITE ENHANCE int I O 0xC0044D1E SOUND MIXER WRITE LOUD int I O OxCO044DFF SOUND MIXER WRITE RECSRC int I O include linux umsdos fs h Ox000004D2 UMSDOS READDIR DOS struct umsdos ioctl I O 0xOO0OO04D3 UMSDOS UNLINK DOS const struct umsdos_ioctl xOOQOUOASDA UMSDOS RMDIR DOG const Struct umsdos Joctl 0x000004D5 UMSDOS STAT DOS struct umsdos ioctl I O Ox000004D6 UMSDOS CREAT EMD const struct umsdos ioctl 0x0O00004D UMSDOS UNLINK EMD const struct umsdos_ioctl 0x000004D8 UMSDOS READDIR EMD struct umsdos ioctl I O Ox000004D9S UMSDOS GEIVERSION struct umsdos_ioctl 0x000004DA UMSDOS INIT EMD void Ox0U0004DB UMSDOS DOS SETUP const struct umsdos octl OxOOOUOADO UMSDOS_RENAME DOS const Struct umsdos ioctl lt include linux vt h gt 0x00005600 VI OPENORY int 0x00005601 VT GETMODE struct vt mode Os0000S5602 VI_SEIMODE const Struct vt mode 0x00005603 XT GETSTATE struct vt stat 0x00005604 VT SENDSIG void sxgOOSUS50S5 VI RELDIGP Imt 0x00005606 VT ACTIVATE int file
157. E 0x00000605 LPSETIRQ int 0x00000606 LPGETIRQ int 0x00000608 LPWAIT int 0x00000609 LPCAREFUL int 0x0000060A LPABORTOPEN int 0x0000060B LPGETSTATUS int 0x0000060C LPRESET void scODODDSO0D LPGETSTATS Struck lp stats lt include linux mroute h gt OxUO005950 SIOCGETVIECNT struct silioo vif req 1 0 0x000089E1 SIOCGETSGCNT struct sioc sg req I O Ifl lt inelude linux meLo n gt Ox4200 SoDUT MITOCTOP cGns Stc wc 0x801C6D02 MTIOCGET struct miger soDUAODOS MTIQCPOS Seruce MEDOS 0x80206D04 MTIOCGETCONFIG struct mtconfiganfo 0x40206D05 MIIOCSEICONFIG Const Struck mtcoonfiginto lt include linux netrom h gt OxODODBESED0 STOCNRGETPARMS struct mr perms struce 1 0 xOUOOUSSEI SITOCNRSETPARMS const struct nr psrms struct 0x000089E2 SIOCNRDECOBS void scUODOUSSES SIOCNRRICTL Constr ane lt include linux sbpcd h gt 0x00009000 DDIOCSDBG const int 0x00005382 CDROMAUDIOBUFSIZ int ixnclude linux scc h Ox00005470 TICCSCCINI void Ox000054 71 TIOCCHANINI const struct scce modem Ox00005472 TIOCGKISS struct ioctl command 7 TO Ox0C00S4 73 TIOCSKISS const struck rocetl command 0x 00005474 TIOCSCOSLAT Struct sec ster include linux scsi h Ox00005362 SCSI IOCTL GEI IDLU struct ant 2 0x00005383 SCSI IOCTL TAGGED ENABLE void file G Linux http www vaxxine com pegasoft people html book 99_e html 8 of 15 7 20 2001 11 40 32 AM
158. ERSTON INE BAT LOC SETVERSION const Ine lt inelude linux fd h gt 0x00000000 0x00000001 0x00000002 FDCLRPRM void EDSETPRM Const struct tloppy struct EDDEFPRM Const Struct rLoppy struct file G Linux http www vaxxine com pegasoft people html book 99_e html 4 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E 0x00000003 FDGETPRM struct tloppy struct 0x00000004 FDMSGON void 0x00000005 FDMSGOFF void 0x00000006 FDFMTBEG void OxOQUODOUOT FDEMITRE Const struct format descr 0x00000008 FDFMTEND void 0x0000000A FDSETEMSGTRESH int 0x0000000B FDFLUSH void 0x0000000C FDSETMAXERRS const struct floppy max errors 0x0000000E FDGETMAXERRS struct floppy max errors 003 0 0 0 010 0 7E O EDGE EDRA TY P Struct char pel 0x00000014 FDSETDRVPRM const struct floppy drive params 0x00000015 FDGETDRVPRM struct floppy drive params 0x00000016 FDGETDRVSTAT struct floppy drive struct 0x00000017 FDPOLLDRVSTAT struct floppy drive struct 0x00000018 FDRESET int 0x00000019 FDGETFDCSTAT struct floppy fdc state 0x0000001B FDWERRORCLR void 0x0000001C FDWERRORGET struct floppy write errors DxOOOOO00IE EFDRAWCMD struct floppy raw cmd MORE T O 0x00000028 FDIWADDLE void M uncolude ilinux fs h Ox000012Z5 D BLRBOSET const anc OxO0Q0UOI25E BhKBOGEI ant 0x0000125F BLKRRPART void 0x00001260 BLKGETSIZE ift 0x00001261 BLKFLSBUF void 0x00001262 BLKRASET
159. Handler is procedure HandleSIGTERM is normal kill signal handler begin Put Line Ouch I ve been killed perform any other cleanup here end HandleSIGTERM end SignalHandler file G Linux http www vaxxine com pegasoft people html book 14 html 5 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming To put the handler in place permanently use pragma Attach_Handler pragma Attach_Handler HandleSIGTERM SIGTERM Now whenever your program receives a SIGTERM signal your handler will automatically run If you don t want to install a permanent handler a handler can be installed or changed while the program is running To indicate that a procedure is an interrupt handler that can be installed at a later time use pragma Interrupt_Handler pragma Interrupt Handler HandleSIGTERM J Gnat automatically handles one signal for you SIGINT the interrupt signal This is the signal that is sent to your program when control c is pressed If you want to handle control c presses yourself you have to use pragma Unreserve All Interrupts Despite it s long name this pragma simply tells Gnat to ignore SIGINT s Certain signals can never be caught SIGUNUSED the unused signal can t be caught for obvious reasons Some signals are used by the multithreading software and are not available for use in applications In particular if you are running native Linux threads you can t catch SIGFPE SIGI
160. IO Histaniuec Wide Tex TO package for short floats Generic package for a siocst Ada Sequential_IO C_Streams reading writing sequential C files a nllefu file G Linux http www vaxxine com pegasoft people html book 99 f html 3 of 9 7 20 2001 11 40 56 AM Big Online Book of Linux Ada Programming Appendix F a siteio Ada Short Integer Text IO sos T DESC for short integers a siwtio Ada Short_Integer_Wide_Text_IO ns VIG Text 10 package for short integers a ssicst Ada Streams Stream IO C Streams package fortcadinp writing C Es m Text IO package for a ssitio Ada Short Short Integer Text IO dup E EU Ada Short Short Integer Inst Wide Text IO package Wide Text IO for short short integers a stmaco Ada Strings Maps Constants Upper set Lowe paper one other char mappings a storio Ada Storage_IO I Ada Stings Bounded D Ada bona dedenie package la stream Ada Streams Standard Ada streams package bes Ada Sings Fixed ee Ada Ne stnngs package a string Ada Strings Standard Ada string defn s bcsimap Ada Strings Maps ee Ada string mapping a strsea Ada Strings Search Internal Use Use strunb Ada Strings Unbounded a ances unbounded strings package sso Ada teams Seam IO nee ie src package Additional unbounded string subprograms la stwibo Ada Strings Wide_Bounded Wide bounded strings package a stwifi Ada Strings Wide_Fixed Wide fixed strings package a stwima Ada St
161. LINE int 0x80044D07 SOUND MIXER READ MIC int 0x80044D08 SOUND MIXER READ CD int 0x80044D09 SOUND MIXER READ IMIX int 0x80044D0A SOUND MIXER READ ALTPCM int 0x80044DO0B SOUND MIXER READ RECLEV int 0x80044D0C SOUND MIXER READ IGAIN int Ox80044D0D SOUND MIXER READ OGAIN int 0x80044DOE SOUND MIXER READ LINE1 int Ox80044D0F SOUND MIXER READ LINE2 int 0x80044D10 SOUND MIXER READ LINE3 int 0x80044D1C SOUND MIXER READ MUTE int 0x80044D1D SOUND MIXER READ ENHANCE int 0x80044D1E SOUND MIXER READ LOUD int 0x80044DFF SOUND MIXER READ RECSRC int 0x80044DFE SOUND MIXER READ DEVMASK int 0x80044DFD SOUND MIXER READ RECMASK int 0x80044DFB SOUND MIXER READ STEREODEVS int 0x80044DFC SOUND MIXER READ CAPS int file G Linux http www vaxxine com pegasoft people html book 99_e html 11 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E 0xC0044D00 SOUND MIXER WRITE VOLUME int I O 0xC0044D01 SOUND MIXER WRITE BASS int I O 0xC0044D02 SOUND MIXER WRITE TREBLE int I O 0xC0044D03 SOUND MIXER WRITE SYNTH int I O 0xC0044D04 SOUND MIXER WRITE PCM int I O 0xC0044D05 SOUND MIXER WRITE SPEAKER int I O 0xC0044D06 SOUND MIXER WRITE LINE int I O 0xC0044D07 SOUND MIXER WRITE MIC int I O 0xC0044D08 SOUND MIXER WRITE CD int I O 0xC0044D09 SOUND MIXER WRITE IMIX int I O OxC0O044DO0A SOUND MIXER WRITE ALTP
162. LL SIGSEGV SIGBUS SIGTRAP SIGABRT SIGINT SIGVTALRM SIGUNUSED SIGSTOP or SIGKILL On 2 0 kernels or older native Linux threads use SIGUSRI and SIGSUR2 and are not available If you re running FSU threads then SIGALRM is also not available Ada Interrupts also contains several subprograms for signal handling Is Reserved is true if a particular signal is uncatchable Is Attached is true if a particular signal has a handler attached Current Handler returns a pointer to the handler for a particular interrupt Exchange Handler will put a new handler in place and return a pointer to the previous handler Detach Handler will uninstall a handler The following package sets up three signal handlers which display a message at set the EMERGENCY SHUTDOWN variable to true The demo program demonstrates some of the Ada Interrupts subprograms and enters into a slow loop The main program was killed with the kill SIGPWR shell command simulating a power failure signal with Ada Interrupts Names use Ada Interrupts Ada Interrupts Names package SigHand is Package to handle basic Linux signals pragma Unreserve All Interrupts Gnat will no longer handle SIGINT for us EMERGENCY SHUTDOWN boolean false set in the event of a signal to shut down the program SignalHandler will handle the signals independently from the main program using multithreading protected SignalHandler is file G Linux http www vaxxine
163. Moving forward three elements it now points at 8 Subtraction moves the pointer backwards Moving backwards two elements it now points at 4 file G Linux http www vaxxine com pegasoft people html book 17 html 6 of 11 7 20 2001 11 37 39 AM 9 gt 0 Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada Virtual_Length gives the length from the pointer to the default terminator The length from this position is 7 positions Virtual_Length can also use an arbitrary terminator The length from the pointer to the first 14 is 5 positions Value returns the array slice from the pointer position to the terminator The array value from this position is 1 gt 4 2 gt 6 3 gt 8 4 gt 10 5 gt 12 6 gt 14 7 gt 16 8 gt 0 Value can also return a slice of a specific length The next four elements are 1 gt 4 2 gt 6 3 gt 8 4 gt 10 Our second array contains 1 gt 12 2 gt 134531961 3 gt 12 4 gt 1 5 gt 134560412 6 gt 134891560 7 gt 134575980 8 gt 0 9 gt 134560432 Copy_Terminated_Array copies elements from one pointer to another up to and including the terminator Copying to the second array JE ME MEE Mu Oo LA gt 6 M MEER SEES IG Copy Array copies a specific number of elements Copying 4 elements from 3 positions ahead the new array contains 1 gt 10 2 gt 12 3 gt 14 4 gt 16 5 gt
164. Online Book of Linux Ada Programming 18 Data Structures Put_Line Assigning dynamically allocate value to a smart pointer accountingPtr deptPtrs Create department Put_Line The accounting pointer points at amp deptPtrs Value accountingPtr all img New_Line Put_Line Assigning a smart pointer to a smart pointer accounting Ptr account ingrPtr Put_Line The accounting pointer 2 points at amp deptPtrs Value accounting2Ptr alltimg New_Line Put_Line The memory is released when the program ends or no more pointers Put_Line access the memory end sp_demo This is a demo of the Booch components smart pointers Assigning dynamically allocate value to a smart pointer The accounting pointer points at ACCOUNTING Assigning a smart pointer to a smart pointer The accounting pointer 2 points at ACCOUNTING The memory is released when the program ends or no more pointers access the memory 18 1 18 Booch Multithreading Booch components can be guarded manually locking the structure for exclusive access or synchronized implicit blocking for multithreading purposes Guarding is implemented by creating extending a container type to a Guarded_Container using the GC Containers Guarded package Guarded containers contain two new subprograms Seize and Release to lock and unlock a container This is implemented using a semaphore Any Booch data stru
165. PPIOCSASYNCMAP const int 0x00005494 PPPIOCGUNIT int O20000S4 9S PREIOCSINPSIGOGONSE ink DxO00005497 PPPIOCSDEBUG const ing 0x00005499 PPPIOCGDEBUG int scODOUDSA99 PPPIOCGSTAT sttuct ppp stars 0x0000549A PPPIOCGTIME struct ppp ddinfo 0x0000549B PPPIOCGXASYNCMAP struct int 8 0x0000549C PPPIOCSXASYNCMAP const struct int 8 OxO0G00549D PPPIOCSMRU const ing 0x0000549E PPPIOCRASYNCMAP const int OxOOQUU549F PPPIOCSMAXCID const int include linux ipx h se 0 0G mU SIOCATPXIIPCRE const ehar 0x000089El1 SIOCAIPXPRISLT const char OsOOODSOSES SIOCIPXCEFGDATA Struck 1px contig data include linux kd h xOUOUOUdTBOD GIO FONT struct char 8192 file G Linux http www vaxxine com pegasoft people html book 99_e html 6 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E 0x00004B61 0x00004B6B 0x00004B6C 0x00004B70 0x00004B71 0x00004B2F 0x00004B30 0x00004B31 0x00004B32 0x00004B33 0x00004B34 0x00004B35 0x00004B36 0x00004B37 0x00004B3A 0x00004B3B 0x00004B3C 0x00004B3D 0x00004B40 0x00004B41 0x00004B69 0x00004B6A 0x00004B66 0x00004B67 0x00004B68 0x00004B44 0x00004B45 0x00004B62 0x00004B63 0x00004B64 0x00004B65 0x00004B46 0x00004B47 0x00004B48 0x00004B49 0x00004B4A 0x00004B4B Ox00004B4C 0x00004B4D Ox00004B4E E G P G K K K K K K K K K K K K K G P G GI E K K K K K K K K
166. Predefined Text IO packages for Numeric Types Type Text IO Package Short Float wide text AdaShot Float Wide Text IO Short Integer wide text AdaShor Integer Wide Text IO Integer j Adamteger Text JO file G Linux http www vaxxine com pegasoft people html book 10 html 11 of 29 7 20 2001 11 33 06 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada Unbounded Sting Ada Unbounded JO Wide Unbounded String AdaWide Unboundd IO Calender Time jGmtTim TO 10 4 Type Attributes Ada has a selection of attributes or built in functions that can be applied to types and variables Attributes are attached to the end of a type or variable name using a single quote The most useful attribute the img attribute returns the ASCII image of what it s attached to which is handy for printing values on the screen using only Ada s Text IO package 5 img for example is the string 5 false image the image of the boolean value false is the string FALSE in capital letters One quirk of img is that if the value is a positive number img adds a leading blank img is a GNAT shorthand for the Ada attribute image image requires you to specify the type of the parameter integer image 5 is the string 5 This attribute is useful on complicated expressions where img won t work because of the lack of parentheses Here s a list of Ada 95 attribute
167. Text IO 10 3 Fundamental Data Types 10 4 Type Attributes 10 5 Operatiors and Expressions 10 6 Variable Declarations 10 7 New Types 10 7 1 Modular Types 10 7 2 Text IO and New Types 10 8 Aggregate Types file G Linux http www vaxxine com pegasoft people html book book html 4 of 10 7 20 2001 11 22 56 AM The Big Book of Linux Ada Programming 10 9 Enumerated Types 10 10 Procedures and Function 10 11 Flow of Control 11 Advanced Ada Programming 11 1 Packages 11 2 Controlling Elaboration 11 2 1 First line of defense Pure Preelaborate and No_Elaboration_Code 11 2 2 Second line of defense Elaborate Elaborate Body Elaborate_All 11 2 3 Other Elaboration Pragmas 11 3 Objects 11 4 Objects with Automatic Initialization Finalization 11 5 Multiple Inheritance 11 6 Private Objects 11 7 Generics 11 8 Exceptions 11 9 Dynamic Allocation 11 10 Callbacks 11 10 1 Storage Pools 11 10 2 Access Parameters 11 11 Multithreading 11 11 1 FSU vs Native Threads 11 11 2 Tasks 11 11 3 Task Types 11 11 4 Protected Items Types 11 12 Ada Text Streams 11 13 Pragmas 11 14 Low Level Ada 12 Standard Gnat Packages 12 1 Standard String and Character Packages 12 2 Advanced Input Output 12 2 1 GNAT IO 12 2 2 GNAT IO_Aux 12 3 Sequential IO 12 4 Direct IO 12 5 Formatted Output 12 6 Calendar Package file G Linux http www vaxxine com pegasoft people html book
168. The Big Book of Linux Ada Programming The Big Online Book of Linux Ada Programming An online documentation project over 27 000 lines long Last Updated July 20 2001 Copyright 1999 2001 Ken O Burtch All Rights Reserved Permission given to copy including photocopying this document for education purposes provided this notice is kept intact Do you want to develop Linux applications twice as fast as the C language Read on Latest version North America Canada Download files zip HTML PDF Unofficial mirrors Europe Spain Asia Japan OOP Web Search the Big Book for a word or phrase L Special Thanks To Jeff Creem user stack and errno clarifications Wilhelm Spickermann CVS Leonid A Timochouk Florist clarifications Jiirgen Pfeifer Multithreading information Bernhard Gubanka Debugging Pools clarifications Eric L Schott Warren W Gay Jean Marc Bourguet Adjust vs C Copy Constructors Jean Marc Bourguet C exceptions Warren W Gay Ada Streams Rush Kesler PDF version Duncan Sands Fortran Elaborate_All Erik Sigra Automake Talk with the author at ken nospam tiamet vaxxine com remove the nospam Hosted by PegaSoft Canada Special thanks to the Ada Linux Team file G Linux http www vaxxine com pegasoft people html book book html 1 of 10 7 20 2001 11 22 56 AM The Big Book of Linux Ada Programming Table of Contents i Preface 1 Introduction
169. The appendices contain a list of the Linux kernel calls file G Linux http www vaxxine com pegasoft people html book 13 html 7 of 15 7 20 2001 11 35 52 AM Big Online Book of Linux Ada Programming 13 Linux Introduction The kernel calls are documented in the online manual pages but these are sometimes out of date due to the ever changing nature of Linux 13 5 2 Devices The dev directory defines device files These files let you work with devices connected to your computer by using standard file operations Devices can include hard drives sound cards and the system console the text display Devices are recognized by their names e dev hd devices IDE hard drives CD ROMs etc dev sd devices SCSI hard drives CD ROMs etc dev fd devices floppy drives e e e dev console device the text display e dev tty devices the pseudo terminals dev tty is an alias for the current tty terminal or ttyS serial port e dev ttyS devices the serial ports dev lp devices the parallel ports Ip stands for line printer In addition most distributions define the following links e dev cdrom an alias for the main CD ROM device e dev modem an alias for the the port device the modem is connected to e dev mouse an alias for the port device the mouse is connected to e dev fd0 an alias for the first floppy drive There are more device files than there are devices on a computer For example there may be 32 serial port device file
170. Threads functions C stream functions Linux Kernel mmap clone function kernel file functions As you move down the list from the standard Ada libraries to the Linux kernel your program becomes more platform specific A program that uses new will run on any operating system that can run Ada 95 If you use malloc your program will run on any operating system that uses has the standard UNIX C libraries available If you use mmap your program will run on any Linux computer not just Intel based Linux but any flavour of Linux include Sun UltraLinux or Apple Mklinux Remember that Linux is a portable operating system all versions of Linux will have mmap available 13 4 Standard C Libraries We ve already covered many of the standard Ada libraries and language features in the above sections The standard C libraries define standardized subprograms that exist across most version of UNIX They are wrappers that is they do not work directly with the kernel For example the standard C libraries are not a part of the kernel but they use the kernel to implement standard C functions that you d find across many UNIX sThe main C library called libc is automatically loaded by Gnat and you can import subprograms from it directly Other standard C libraries such as C s math library libm or the password encryption library libcrypt need to be linked in at the linking stage The standard C library calls are defined in the online man
171. VECEG const Struct slave config EQL GETMASTERCFG struct master config EOL SEIMASTERCEG const struct master config FDRAWCMD takes a struct floppy raw cmd If flags amp FD RAW WRITE is non zero then data points to an input butter of length length If flags amp FD RAW READ is non zero then data points to an output buffer of length length GIO FONTX and PIO FONIX take a struct console tont desc or a a butter ot char Loharcount This 25 an output Hutter for GIO FONTE and an input buffer for PIO FONIX GIO UNIMAP and PIO UNIMAP take a struct unimapdesc or a of struct unipair entry ct This is an output buffer for GIO UNIMAP and an input buffer for PIO UNIMAP file G Linux http www vaxxine com pegasoft people html book 99_e html 13 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E KDADDIO KDDELIO KDDISABIO and KDENABIO enable or disable access to I O ports They are essentially alternate interfaces to ioperm KDMAPDISP and KDUNMAPDISP enable or disable memory mappings or I O port access They are not implemented in the kernel SCSI IOCIL PROBE HOST takes an input pointer const ant which is a length It uses the same pointer as an output pointer to a char buffer of this length SIOCADDRT and SIOCDELRT take an input pointer whose type depends on the protocol Protocols cons struct reentry AX 25 const Struct ax25_ route NET ROM
172. _IO Ada Numerics Elementary_Functions Ada Numerics Generic_Elementary_Functions use Ada Text IO Ada Numerics Elementary Functions file G Linux http www vaxxine com pegasoft people html book 12 html 30 of 35 7 20 2001 11 34 28 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages procedure floatmath is type percent is new float range 0 0 1 0 package percentMath is new Ada Numerics Generic_Elementary_Functions percent use percentMath half percent 0 5 begin Put Line Here s some floating point math New Line Put_Line 4 0 to the power 3 0 is amp float mage 4 0 30 J J Put_Line The sine of 0 4 radians is amp float image sin 0 4 Put Line The cosine of 180 degrees is amp float image Sala 180 0 360 0 Put_Line The square root of 81 is amp float image sqrt 81 0 Put_Line 50 squared is amp percent image half Dye end floatmath Here s some floating point math 4 0 to the power 3 0 is 6 40000E 01 The sine of 0 4 radians is 3 89418E 0 The cosine of 180 degrees is 0 00000E 00 The square root of 81 is 9 00000E 00 50 squared is 2 50000E 01 When you work with floating point subprograms in libraries outside of Ada there s a chance that the library will change the floating point arithmetic settings for your CPU When this happens use the GNAT Float Control package to change your CPU back to GNAT s pref
173. _error gt Total 0 when storage error gt Total 1 when others gt raise end exceptional Raise causes the exception to be reraised to the calling subprogram If one subprogram doesn t handle the exception it s raised in the subprogram that called it This continues until the exception is handled by an exception part or the main program is it In the worst case if the main program has no exception part the program terminates and the exception name is printed on the screen One use for exception parts to deallocate access types so the memory isn t lost when unexpected errors occur You can define and raise your own exceptions procedure exceptional2 is Accounting Error exception C Ada exceptions do not carry any additional information when raised You can simulate error messages and other information with global variables Pragma Assert provides an exception for debugging programs Assert is described in 8 2 For more advanced manipulation of exceptions you ll need to use Ada Exceptions and its related packages These are described in 12 15 file G Linux http www vaxxine com pegasoft people html book 11 html 14 of 39 7 20 2001 11 33 45 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming 11 9 Dynamic Allocation Ada Description C Equivalent new Allocate new memory malloc mallopt unchecked_deallocation Deallocate memory free Dynamic allocation is reserving memory for var
174. a version of your program for public release without having to delete the debugging statements from your source code Pragma Assert lets you test to make sure a certain condition is true If it isn t then an exception is raised Use Assert to check for conditions which you assume are true during program development This is especially useful when several programmers are working on a project and you don t know if a condition will change in the future pragma Assert ScreenHeight 24 file G Linux http www vaxxine com pegasoft people html book 8 html 1 of 6 7 20 2001 11 32 24 AM Big Online Book of Linux Ada Programming 8 Debugging Your Project In this example if the variable ScreenSize is not 24 an ASSERT_ERROR exception is raised Pragma Debug lets you call a procedure for debugging purposes For example you can use this to print information about the program while it is running Because this is a pragma you can place it almost anywhere even in the middle of variable declarations x i 5 pragma Debug PrintToLogFile X is now amp x img If PrintToLogFile is a procedure that saves messages to a log file this example saves the message X is now 5 to the log file Pragma debug can be disabled with pragma Suppress Debug Info Pragma No Return can be used to indicate subprograms that never complete This suppresses the related compiler warnings Pragma Normalize Scalars initializes anything not an array re
175. access procedure DoComplexSlowComputation updatePtr To call a callback use the dereference operator all UpdatePtr all 11 10 1 Storage Pools Unlike languages like C that have only one storage pool Ada allows you to define your own storage pools Authors of real time applications for example can create a pool with a maximum size limit or a fixed access time Use a for clause to make an access type use a pool other than the default storage pool type AccountingRecPtr is access all AccountingRec file G Linux http www vaxxine com pegasoft people html book 11 html 16 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming for AccountingRecPtr storage pool use my pool Gnat defines several storage pools besides the default storage pool Perhaps the most useful is the debug pool This storage pool available in version of Gnat before 3 12 works the same as the default storage pool except that it performs run time checks for several different pointer related problems If a check fails an exception is raised The following program illustrates the errors caught by debug pool access types with Ada Text IO System Pool Local System Debug Pools use Ada Text IO with unchecked deallocation This is an example of using the GNAT specific debug pool storage pool procedure debpools is type sales record is record salesman code integer sales amount fl
176. ackage is portable to all operating systems the format of the directory depends on the particular operating system For this package a directory name string Dir Name Str is a pathname in the standard Linux format The trailing character is optional when using this package but directory names returned will always have a trailing is the current directory is the parent directory of the current directory Get Current Dir returns the name of the current directory Change Dir changes the current directory to a new location with ada text io gnat directory operations use ada text io gnat directory operations procedure gdir is Quar sEraDOQCl 90 5 len mentes a lv begin Pur rhe current working directory is Jy Pun anel Get Current Dir Change Dari Yi J Put Moving up the current working directory is Put Taine Geb Current Dir file G Linux http www vaxxine com pegasoft people html book 14 html 12 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming Change Dir work Get Current Dir dir len Put Moving down to work the current working directory is Put maine diri len end dir The current working directory is home kburtch work Moving up the current working directory is home kburtch Moving down to work the current working directory is home kburtch work For viewing directories the package opens directories
177. actly which subprogram will be used for a particular tagged record type they don t need to read the entire class to make sure the subprogram isn t overridden later on The disadvantage is that if file G Linux http www vaxxine com pegasoft people html book 11 html 7 of 39 7 20 2001 11 33 45 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming you can t use a classwide type you ll have to write subprograms for each and every type in that class In these cases typecasting is useful Tagged record types can be typecast as other tagged record types in the same class using typecasting You need to do this if you want a dispatching call inside of a dispatching call For example if anEmployeeProfile has a GetSalaryRate function we could call it by procedure WriteEmployeeSalary e aSalaryEmployee class is begin Text IO Put Line The salary is amp GetSalaryRate anEmployeeProfile e end WriteEmployeeSalary 11 4 Objects with Automatic Initialization Finalizaton Ada Controlled Object Call Description C Equivalent z nitialize Initialize an object constructor Adjust Fix object after assignment copy constructor Finalize Clean up an object destructor Basic Ada tagged records don t do anything special when they are created or destroyed If you want special actions to be executed automatically when a tagged record is created or destroyed you can use the Ada Finalization package In thi
178. adb gdir2 sq gan r20 gr 2 End of directory The directories and are always returned New directories can be made with Make_Dir Make_Dir logs make a new logs directory If you need more features that these the Linux kernel calls for directories are described in 16 9 The section includes a command to remove directories which cannot be done with Gnat Directory Operations 14 7 GNAT Lock Files Package This Gnat package contains subprograms for obtaining exclusive access to a particular file or directory When a file is locked only your program may use the file until the file is unlocked Locks are implemented using lock files When a file is locked Gnat checks for the presence of a separate file If the file exists the file has been locked by another application If a file cannot be locked a LOCK ERROR is raised The programmer supplies the lock file name Linux programs usually place lock files in the var lock directory The Lock File procedure locks a particular file By default if the procedure will continue trying to relock the file every second forever actually for Natural Last seconds a very long time The delay and the number of retries can be changed Lock Frle var lock oustomers txt Lock File var lock customers txt j file G Linux http www vaxxine com pegasoft people html book 14 html 14 of 15 7 20 2001 11 36 20 AM Big Online Book of Linux Ada Programming 14 Li
179. agma import C fcntl Set flags for open kernel call Only async nonblock and appending can be changed procedure fcntl result out integer fd file id operation gt F_GETLK lock in oUt LOCKS Edere qe i return integer pragma import C fcntl pragma import valued procedure fcntl Return a copy of the lock that prevents the program from accessing the file or else if there is nothing blocking the type of lock procedure fcntl result out integer fd file id operation gt F_SETLK lock in OUEMLOCTS truc return integer pragma import C fcntl pragma import valued procedure fcntl Place a lock on the file If someone else has locked the file already 1 is returned and errno contains the locking error procedure fcntl result out integer fd file id operation gt F_SETLKW lock in out loCkstruct return integer pragma import C fcntl pragma import valued procedure fcntl Place a read or write lock on the file or to unlock it If someone else has locked the file already wait until the lock can be file G Linux http www vaxxine com pegasoft people html book 16 html 13 of 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming placed Additional information about locks are found in usr src linux Documentation locks txt type aLock is new short integer
180. aits for a new connection unless you disabled blocking on the socket myaddr is the address of the incoming connection and addrlen is the size of the address is bytes addrlen should be initialized to the size of your sockaddr record You must use listen before accept Returns 1 on failure or a new socket with the connection on success You have to close the new socket when you are finished handling the connection Example len clientaddr size 8 accept newsocket listensocket clientaddr len This section ends with a demonstration of how to get a web page off the Internet with Ada Text IO Interfaces C System Address To Access Conversions use Ada Text IO Interfaces C procedure websocket is A program to fetch a web page from a server Socket related definitions These are the kernel calls and types we need to create and use a basic Internet socket type aSocketFD is new int a socket file descriptor is an integer man socket make this a new integer for strong typing purposes type aProtocolFamily is new unsigned short AF INET constant aProtocolFamily 2 Internet protocol PF Net defined as 2 in c Uiste iste Jeena ome lude dis bau Societe N Make this a new integer for strong typing purposes type aSocketType is new int SOCK STREAM constant aSocketType 1 this is for a steady connection Defined as 1 in usr src li
181. al size is 0 Added customer 7456 The The bag is empty FALSE bag extent is 1 Added customer 9362 The The The bag is empty FALSE bag extent is 2 bag total size is 2 Added customer 9362 The The Ea bag is empty FALSI bag extent is 2 Booch components bags amp Cusvomer Bags lel amp customerBag Is_Empty amp ec img amp customerContainers Is_ amp eame amp customerContainers Is_ customers img customers img tal Size customers img Done i img Done i img Done i img no item at this position in the bag file G Linux http www vaxxine com pegasoft people html book 18 html 10 of 26 7 20 2001 11 38 17 AM Vi Big Online Book of Linux Ada Programming 18 Data Structures The bag total size is 3 Resetting the iterator The current item is customer id 7456 Are we done FALSE Advancing to the next item The current item is customer id 9362 Are we done FALSE Advancing to the next item Are we done TRUE BC NOT_FOUND exception no item at this position in the bag Bags are useful for counting the occurrences of an item in a large amount of data 18 1 6 Sets Sets are essentially the same as bags but may not contain duplicates The are useful for detecting the presence absence of an item or representing flags or conditions with BC Containers Sets Bounded wi
182. al string is Ihis is a TESI SEring Upper case is THIS IS A TEST_STRING Lower case is this is a test_string Mixed case is This is a test_String Ada defines a number of character sets ASCII is the standard ASCII character set To put an character on displays that support the Latin character set use Pat Ada Characters lidtin ihe AmeDaothmonmndg 95 12 2 Advanced Input Output 12 2 1 GNAT IO For small programs that don t need the full capabilities of Text IO GNAT provides a package called GNAT IO This package can get and put integers characters and strings Unlike Text IO it s also preelaborated with GNAT IO use GNAT IO procedure giodemo is this program demonstrates basic input output using the GNAT IO package a stripped down version of Text IO Cc character this is a letter begin Put Line This program displays information on the screen Put Line and reads information from the keyboard New Line Put Line Put Line displays a line of text and advances to Put Line the next line Pue Pue y Put_Line displays text but it doesn t start a new line Put_Line New_Line displays a blank line New_Line Put_Line Get waits for a character to be typed Put_Line Type a key and the Enter key to continue Get c P t _Line The character you typed was e ee TIm J end giodemo This program displays informa
183. alization of maps where any number of items can be related to each other as opposed to only two A directed graph is a set of items vertices that are connected by relationships edges or arcs Like a single linked list a program can only move forward along an arc Items can also be linked to themselves The graphs directed package provides the following subprograms e Create Arc add a relationship between two items e Number Of Incoming Arcs return the number of incoming arcs to an item e Number Of Outgoing Arcs return the number of outgoing arcs to an item e Set From Vertex move an arch s source to a new item file G Linux http www vaxxine com pegasoft people html book 18 html 23 of 26 7 20 2001 11 38 18 AM Big Online Book of Linux Ada Programming 18 Data Structures e Set To Vertex move an arc s destination to a new item e From Vertex return the source item for an arc e To Vertex return the destination item for an arc There are four iterators a graph iterator and three iterators for visiting items incoming outgoing and both An undirected graph is a directed graph with pointers to both the previous and next item along an arc Like a double linked list a program can move forwards or backwards along an arc The graphs undirected package provides the following subprograms e Create Arc add a relationship between two items e Arity return the number of arcs Self arcs are counted only once e Set Firs
184. alue of an environment value Remember the string returned is a C string with an ending ASCIL NUL 16 6 Multitasking Multitasking creates child processes to do tasks for your main program On multiprocessor machines different processes can be assigned to different processors allowing work to be done simultaneously On single processor machines the processor switches several times a second between processes and does a little work on each The function to create a new child process is called fork When Linux creates a new process it doesn t start by creating a blank process Instead it makes a copy of the original process so there are effectively two copies of your program running The fork function returns a value to tells your program if it is the original program or the new copy If you want to run a different program you ll have to use one of the exec family of functions to load and run the new program The exec functions destroy the old program and run a new program in its place The above section Using System and OSLib Spawn has an example C function called Crunlt that uses fork to start a new process and run a new program type pid t is new integer function fork return pid t pragma import C fork Create a new child process identical to the original process and return 0 if the program is running as the child process or the PID of the parent if the program is running as the original parent process Example myPID fork proced
185. am result out integer fid 2 abalike T9 alto lene ire xehe LIED ignored in out aDummyParam pragma import C ioctl noparam ioctl pragma import valued procedure ioctl noparam type cdrom ti is record start track start index byte end track end index byte end record from usr src linux include linux cdrom h PLAYTRKIND ioctl function uses cdrom ti record procedure ioctl playtrkind result out integer Eid lt amileID Id roct TD ipfo gt In out cdrom ti pragma import C ioctl_playtrkind ioctl pragma import_valued_procedure ioctl_playtrkind KERNEL CALLS Calls to the Linux kernel besides ioctl file G Linux http www vaxxine com pegasoft people html book 13 html 9 of 15 7 20 2001 11 35 52 AM Big Online Book of Linux Ada Programming 13 Linux Introduction procedure open id o parto String flags integer pragma import C open pragma import_valued_p open is a kernel ca procedure close resul pragma import C clos pragma import valued p close is a kernel c C IIIS ESAE GAINS Calls to the standa procedure perror pre ut aFileID 7 open gt rocedure open 11 to open a file t out integer id aFile ep Closet rocedure close all to close a file rd Linux C libraries iestr 12 String pragma import C pe
186. ammers The script command creates a file called typescript in the current directory The typescript file is a text file that records a list of everything that appears on the screen You can stop the recording process with the exit command 9 5 Timing Execution with Time The shell command time will tell you how long a program took to run and reports general statistics such as how many page faults occurred armitage home ken ada sm time myprog 3 09user 0 95system 0 05 84elapsed 69 CPU Oavgtext 0avgdata Omaxresident k Oinputs Ooutputs 478 6major 4235minor pagefaults Oswaps lt Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 9 html 6 of 6 7 20 2001 11 32 37 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada 10 An Introduction to Ada lt Last Chapter Table of Contents Next Chapter gt Ada is a full featured language with many capabilities rules and nuances Although the fundamentals are easy to learn Ada somewhat resembles BASIC it is several times larger that C and to truly master the language requires considerable practice To make understanding easier the discussion is broken up into two chapters This chapter outlines the basics of the language and the next chapter discusses features for team development large projects and other specialized tasks This in no way covers everything there is to know about Ada I ve chose
187. amming Put Lzne HandleKull Program zs shuttarng down end if EMERGENCY SHUTDOWN TRUE end HandleKill procedure HandlePowerFailure is power failure handler begin if EMERGENCY SHUTDOWN then Put Line HandlePowerFailure The program is already shutting down else Put Line HandlePowerFailure Program is shutting down end if EMERGENCY SHUTDOWN TRUE end HandlePowerFailure end SignalHandler end SigHang with Ada Text IO SigHand Ada Interrupts Names use Ada Text IO SigHand Ada Interrupts Ada Interrupts Names procedure SigDemo is Handler Parameterless Handler Counter integer 2 begin Put Line This program demonstrates signal handling Put mnel To stop this program type Control Clor Put Line essct with the shell kill command 9 New_Line Is Reserved example if Is Reserved SIGTERM then Put Line The SIGTERM handler is reserved else Put Line The STGIERM handler isn t reserved gt end if Is Reserved example if Is Attached SIGINT then Put Line There as a SIGINT handler anstalled file G Linux http www vaxxine com pegasoft people html book 14 html 8 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming else Put _Laine DIhere as no SIGINT handler installed end if Current Handler example Put_Line Testing SIGTERM handler Handler Current_Handle
188. ample shmat ShmCPtr myID To Address null 0 SIYE ee e To Address ohmetan SHM_RDONLY this memory is read only that is as if it was constant SHM_RND allows your shmaddr to be truncated to a virtual memory page boundary function shmdt shmaddr system address return integer pragma import C shmdt Shared memory detach Removes the association of the shared memory to the pointer Returns 0 if the memory was detached for failure Example Result shmdt To Address ShmPtr function shmctl shmid integer cmd integer info system address return integer pragma import C shmctl Performs miscellaneous shared memory functions including deallocating shared memory allocated with shmget Returns O if the function was successful or 1 for a failure Example Result shmctl myID IPC RMID To Address null IPC RMID deallocate shared memory 16 21 Message Queues 16 22 Semaphores file G Linux http www vaxxine com pegasoft people html book 16 html 37 of 47 7 20 2001 11 37 16 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming 16 23 Sockets Send sentto and sendmsg are supersets of write When you use write on a socket it s actually implemented using the send family Write will not work on UDP because it s connectionless Use send to specify an address everytime Protocol Families PF INET Internet IPv4 PF INETSO Internet IPv6 PF IPX
189. an be specified when record variables are declared Bob employseRrotile 1Bob Smith 35 000 0 37 Denise employeeProfile name gt Denise Jones salary gt 39 000 0 age gt 42 In the above examples we are creating a temporary record and then assigning that record to the variable You can use this in the executable part of your program not just in declarations Ada will require a subtype mark an indication of what type of record you are making NewRec employeeProfile Bob Smith 35 000 0 37 employeeProfile indicates that the record we ve built should be treated as an employeeProfile record file G Linux http www vaxxine com pegasoft people html book 10 html 21 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada Although this looks almost exactly the same as type casting it isn t type casting Consider the following J long_integer 5 J long integer 5 The first statement clarifies that 5 is a long integer this is a hint to the compiler that 5 should be treated as an long integer The second converts 5 from an integer to a long integer Record fields are accessed using a period and the field name Bob age 37 A variant record is a record that contains different sets of mutually exclusive information type employeeProfile sex aSex is record name estem o0 salary aSalary ago anigo case sex is when male gt
190. an illegal access If MAP ANON is used fd should be 1 and no file will be associated with the memory otherwise fd is a file that will be copied into the block of memory and offset indicates how many bytes into the file the copying should take place function munmap start system address size long integer return integer pramga import C munmap Deallocate memory allocated by mmap Returns 1 on an error function mremap old start system address old size long integer new size long integer flags aMapFlag return system address pragma import C mremap Changes the size of a block of memory allocated by mmap possibly moving it function mprotect start system address size long integer new prot aProtection return integer pragma import C mprotect Change the protection settings on a block of memory allocated by mmap Returns 1 on an error Other mmap flags PROT NONE constant aProtection OF Shorthand Ole no access PROT READ constant aProtection 1 read access allowed PROT WRITE constant aProtection 2 write access allowed PROT EXEC constant aProtection 4 execute access allowed MAP SHARED constant aMapFlag 164014 share changes with child processes write c
191. an without error non zero values indicate an error The predefined values of Success and Failure are O and 1 Properly flagging errors is important for shell programming For example you have to return the proper exit status for myprog amp amp echo all is well to work properly You can retrieve the exit status of the last command using For example bin bash file G Linux http www vaxxine com pegasoft people html book 14 html 10 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming myprog v sally if 2 eq 0 s then echo There were uo Er COnN else echo The program returned error code 7 fu See the example program in the next section for an example using this package 14 5 Linux Environment Variables Ada Command Line Environment is a gnat package for accessing Linux environment variables Ada Description C Equivalent Function Environment_Count return natural The number of environment variables Function Environment_Value n return string The name value of the nth variable getenv n The Environment_Count function returns the number of environment variables il The Environment_Value function returns the name and value of a variable separated by an equals sign For example Environment_Value 5 returns the name and value of the fifth environment variable The following program is an example of Ada Command_Line and Ada Command_Line Environme
192. apter Table of Contents Next Chapter gt Optimization is the customization of a program to run as small and or as fast as possible on a particular type of computer If you program is running slower than you expected or is using more memory or disk space than you expected you should first examine the approach you used in your Ada source code Can you use better data structures or implement faster algorithms For example a bubble sort is an easy way to sort relatively small amounts of data but a quick sort is faster on thousands or millions of pieces of data In large programs the subprogram causing the biggest bottlenecks may not be obvious Experimenting with different test data and timing the results can often narrow down the problem areas You could also try the gprof profiling tool which will give you statistics on your program performance and will show that you are on the right track Why spend hours or days improving a section of your program that isn t causing the problem This is especially important in a business environment focus your time on the sections that will give the greatest improvements Some optimizations can be done automatically by the Gnat compiler There are both compiler switches and language pragmas for fine tuning your programs 7 1 Compiler Optimization Options There are several compiling switches used to optimize programs The O switch tells the compiler how much time it should spend optimizing the program
193. ars money CanadaToUSExchangeRate end ToUS Set the exchange rate between US and Canada and two functions to convert between currencies end Currency Notice we have access to everything we defined in the package spec we don t need to repeat anything in the body Because the two exchange rate variables are defined inside the package body they are invisible to other programmers Save this package body as currency adb adb for AdaBody Make sure all pragma Stubbed s are removed for the finished subprograms Compile both and you have a working package To use your package in a program use the with statement with text io currency procedure currencyTest is begin Currency SetExchangeRate 1 5 0 7 file G Linux http www vaxxine com pegasoft people html book 11 html 2 of 39 7 20 2001 11 33 44 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Text IO Put Line 1 Canadian dollar is amp Currency ToUS 1 0 img end currencyTest To have Ada check which package a subprogram belongs to and avoid typing the package name constantly use the use statement with currency use currency SetExchangeRate 1 5 0 7 If the use statement creates an ambiguity Ada will warn you that it can t determine which package SetExchangeRate is in Package bodies may have main programs a block at the end of all declarations marked with begin This allows you to setup your pa
194. ary NQS KB Search Replace standard search replace Comment turns hilighted text into a comment Uncomment removes comment marks from hilighted text Convert Keywords to Upper Lowercase changes the case of all keywords in the document Goto Line goto a particular line Insert File insert a source file into this one The View Menu Show Unit Symbols toggles module symbols in CSD diagram Show Data Symbols toggles data symbols in CSD diagram Show Boxes toggles boxes around multiline statements in CSD diagram Intrastatement Align If on for statements longer than one line the second line and onward will be indented to the position of the first open paranthesis Force Newlines If on divides up statements so they will be on separate lines Auto Line Numbers toggles line number display in CSD diagram Auto Indent toggles indentation in CSD diagram Line Numbers adds line number to CSD diagram corresponding to lines in source code Generate CSD creates a Control Structure Diagram for source code Remove CSD removes CSD diagram from source code file G Linux http www vaxxine com pegasoft people html book 3 html 8 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s Show Controls toggles button bar at top of edit area Show message Bar toggles message bar at bottom of window The Templates Menu insert source code for typical Ada multiline statements T
195. as as a package using a specification and a body They act like a package that allows only one task access to its contents at a time While one task is using the contents any other task wanting access is blocked until the first task is finished Here is our CountingTask rewritten as a protected item protected CountingType is procedure add amount integer procedure currentTotal total out integer private runningTotal integer 0 end CountingType protected body CountingType is procedure add amount integer is begin runningTotal runningTotal amount end add procedure currentTotal total out integer is begin total runningTotal end currentTotal end CountingType In this case any task may execute the add or currentTotal procedures but only one task may execute them at a time This ensures that runningTotal will not be corrupted Unlike a package you can t declare variables in the spec or body unless you put them in a private part in the spec Protected items can include entry declarations Since there is no main program to the protected body the protected body contains no accept statements Instead the entry declarations are filled in as if they were a subprogram Any guarding conditions are attached to the end of the entry header For example to create an a version of our add procedure that blocks if the total is higher than 100 we could write protected CountingType is file
196. ate s aSalaryEmployee class return float is begin return s salaryRate end GetSalaryRate We ve declared two one line subprograms that will work on any tagged record derived from aSalaryEmployee C Ada does not require constructors or destructors Creating objects with these are discussed below Subprograms can be marked as unusable in the same way as abstract tagged records An abstract procedure or function is a placeholder Declaring one requires that all types extended from this type must have this subprogram defined If any do not have this subprogram Ada will report an error For example if anEmployeeProfile had a procedure like procedure WriteEmployeeName e anEmployeeProfile is abstract all employee profile records would be required to have a procedure called WriteEmployeeName ASalaryEmployee will have a compilation error unless we add such a function procedure WriteEmployeeName e aSalaryEmployee is begin Text IO Put Line Employee Name amp e Name end WriteEmployeename WriteEmployeeName could also use aSalaryEmployee class to refer aSalaryEmployee or any records we extend from it To avoid ambiguity only one tagged record subprogram can refer to any one type This is different from some other object oriented languages where you can override a classwide subprogram with one that refers to a specific type The advantage of no overriding is that someone reading your class knows ex
197. ause your task to wait for that request and then do nothing You can do this to synchronize two tasks accept WaitUntillTellYouToGo Suppose we add another entry statement to read the current value of the running total task CountingTask is entry add amount integer entry currentTotal total out integer file G Linux http www vaxxine com pegasoft people html book 11 html 23 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming end CountingTask In this case we want the task to check for two different requests The Ada select statement keeps a task from blocking and instead checks for multiple messages task body CountingTask is runningTotal integer 0 begin loop select accept add amount integer do runningTotal runningTotal amount end add or accept currentTotal total out integer do total runningTotal end currentTotal end select end loop end CountingTask In this example the task will repeatedly check for an add request or a currentTotal request To communicate with the task we make calls to the task as if it were a package For example to send a message to add 5 to the running total we d use CountingTask Add 5 Because accept is a statement that executes at run time you can create any kind of message policy you want Some messages can block Some messages can be checked You can force certain message to be han
198. ay some statistics Put Line We created the file amp Name CustomerFile Put Line We re currently using amp Mode CustomerFile img amp mode Put Line There are amp Size CustomerFile img amp records Put Line We are on row amp Index CustomerFile img if Is Open CustomerFile then put e daba t Mta file is opent else Put Line The file isn t open end if New Line write the first record cu name lt Midvilile Electric ie wWeite Customerkile cr Put_Line Writing amp cr name Put_Line There are amp Size CustomerFile img amp records file G Linux http www vaxxine com pegasoft people html book 12 html 12 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages Put_Line We are on row amp Index CustomerFile img New_Line write the next record on row 7 cr name New York Distributors us Wwrite CustomerFile cr To gt 7 P t Line Writing Us ere name k T tO row 7 J P t _Line There are SES XN CustomerFile mm cese records J Put_Line We are on row amp Index CustomerFile img Put Line End of File not allowed on In files begin if End Of File CustomerFile then Put Line We are at the end of the file else Puro laine We aren t at the end of the file end if exception wh
199. back of the queue Pop Remove an item from the front of the queue and return it Remove Remove an item at a particular index Length Return the number of items in the queue Is_Empty True if there are no items in the queue Front Return the item at the front of the queue without removing it Process generic procedure to return an item with processing Location Return the first index where an item appears else 0 Are_Equal True if two queues have the same items and length Copy Copy one queue to another An ordered queue is identical except that append adds an item in sorted order Queues can be bounded dynamic or unbounded Queues provide fair processing and reduce starvation 18 1 9 Stacks Stacks are lists in which the last item placed in the list is the first item removed The Stacks package provides the following subprograms e Clear Remove all items from the stack file G Linux http www vaxxine com pegasoft people html book 18 html 16 of 26 7 20 2001 11 38 18 AM Big Online Book of Linux Ada Programming 18 Data Structures e Push Add an item to the top of the queue e Pop Remove an item from the top of the stack and return it Depth Return the number of items in the stack Is Empty True if there are no items in the stack Top Return the item at the top of the stack without removing it Process Top generic procedure to return an item with processing Are Equal True if two stacks have the same items an
200. begin if n 2 then return 1 else return n factorial n 1 end if end factorial nain E OE em begin put line Browse this source new line put Irine The factorial ot 5 is amp natural umage factorial 5 end htmltest This creates an index file like this Files e htmltest adb Functions Procedures e factorial e htmltest The first link would show you your entire file File htmltest adb with Ada Text IO use Ada Text IO procedure htmltest is a demonstration of gnathtml file G Linux http www vaxxine com pegasoft people html book 6 html 13 of 14 7 20 2001 11 31 54 AM Big Online Book of Linux Ada Programming 6 Development Utilties function factorial n natural compute the factorial of n begin if n amp lt 2 then return 1 else return n factorial m1 end if end factorial marin program begin put_line Browse this source new_line put_line The factorial of 5 is end htmltest return natural is amp natural image The links use the htm not html extension for portability 6 9 GnatFind To be written KB Last Chapter Table of Contents factorial Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 6 html 14 of 14 7 20 2001 11 31 54 AM 5 Big Online Book of Linux Ada Programming 7 Optimizing Your Project 7 Optimizing Your Project lt Last Ch
201. ble is substituted for the word Single Double linked lists are useful for lists that must be browsed backwards and forwards continuously Double linked lists should not be Guarded 18 1 5 Bags Bags like linked lists are collections of items However there is no attempt to order the items Duplicate items can be stored but the bag keeps a count of duplications to save memory instead of storing copies of the duplicates file G Linux http www vaxxine com pegasoft people html book 18 html 7 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures The bags package provides the following subprograms Are_Equal True if two bags have the same contents Clear Removes all items from the bag Add Adds an item to the bag Remove Removes an item from the bag Union Add one bag to another Intersection Remove all items not common between two bags Where there are duplicates keep the lower duplicate count Difference Remove all items not common between two bags Where there are duplicates subtract from the original and discard the item if the total is gt 0 Extent Return the number of distinct items Total_Size Return the total number of items including duplicates Count Return the number of occurences of an item in the bag Is_Empty True if the bag is empty Is_Member True if one or more copies of an item is in the bag Is_Subset True if the contents of one bag is c
202. book html 5 of 10 7 20 2001 11 22 56 AM 12 7 Tags Package 12 8 Tables 12 9 Hash Tables 12 10 Bubble and Heap Sorts 12 11 Regular Expressions 12 12 Advanced String Processing 12 13 GLADE Distributed Processing not finished 12 14 Basic Math Packages 12 15 Exception Handling and Traceback Packages 13 Linux Introduction 13 1 Introduction to Processes 13 1 1 Parents Children and Families 13 1 2 Ownership and Permissions 13 2 Using System and OsLib Spawn 13 3 The Linux Environment 13 4 Standard C Libraries 13 5 The Linux Kernel 13 5 1 Kernel Calls 13 5 2 Devices 13 5 3 Proc File System 13 5 4 AudioCD An Example Program 13 6 Standard Input Output Error 13 9 Linux Libraries 13 10 Libc5 Libc6 and Upward Compatibili 13 11 Linux Basics 14 Linux Programmin 14 1 Gnat OS Library 14 2 Installing Binding Packages 14 3 Catching Linux Signals 14 4 Working with the Command Line 14 4 Linux Environment Variables 14 6 GNAT Directory_Operations Package 14 7 GNAT Lock_Files Package file G Linux http www vaxxine con The Big Book of Linux Ada Programming 15 Free Ada Bindings 15 1 Using Florist a POSIX binding 15 2 Using Texttools 15 2 1 Installation 15 2 2 Introduction 15 2 3 Package Overview 15 2 4 Window Overview 15 2 5 Other Useful Window Manager Subprograms 15 2 6 Alerts 15 2 7 Other Predefined Windows 15 2 8 Control Overview
203. bstr procedure Read Stream out Stream_ El E Elem Stream Memory Buffer Max_l act for Read in out Memory_Buf Elem tr is access all Memory ement Array Last procedure Write Stream Item Rewind procedure Rewind procedure To permit easy destruction of in Stream Rewind the Read Memory Read Stream the Write Memory Rewind Write Stream procedure Free Stream private act for Write in out Memory Bu Element Array Buffer Index Stream Access Buffer Index Stream Access this stream Stream Access Element Offset Object with Fanalizatiaon is new Buffer Stream fer Stream ffer Stream Now ereare a Memory fer stream with an Roo Con trolled type Initialize procedure a Controlled type t_Stream_Type is not derived so it is done privately here U it must be derived nfortunately the type from the from type Memory_Bu Read_Offset Write_Of Fset Buffer end record procedure procedure procedure bte ems Last procedure procedure Initialize ffer Max_ Bu Elem S S S Stream tream Element tream Elemen tream_ eu Offse p Element Offset Oi Sec P Element_Array 1
204. buffer begin tn Read integ heels pu des er 290 Oe aSocketF We is D continue reading until an error or no more data read up to 80 bytes at a time while amountRead 0 loop Read amountRead soc buffer bu if amountRead 0 then Put buffer 1 amountRead end if end loop end ShowWebPage ServerName string www adapower com mySocket aSocketFD the Socker myAddress aSocketAddr where it goes file G Linux http www vaxxine com pegasoft people html book 16 html 42 of 47 7 20 2001 11 37 17 AM ffer length Jr web server s response and display it to the screen 1 Ve Big Online Book of Linux Ada Programming 16 Advanced Linux Programming myserver a EO e 167 IP number of server myServerPtr HEptrs Object_Pointer addrList addrListPtrs Object Pointer Result som begin P Line socket Demonstration y New_Line Put_Line This program opens a socket to a web server Put_Line and retrieves the server s home page New_Line initialize a new TCP IP socket 0 for the third param lets the kernel decid Put_Line Initializing a TCP IP socket Put_Line Socket amp PF INET img amp amp SOCK_STREAM img amp OF j mySocket Socket PF INET SOCK STREAM O0 if mySocket 1 then perror Error making socket amp ASCII NUL
205. c allowing it to produce fast quality executables without any intermediate steps This integration gives a lot of flexibility to programmers who want or need to support multiple languages GNAT has an extensive set of features for trading variables and function calls between Ada and C C It can import C C items into Ada export Ada items to C C You can also link Ada functions indirectly into Java using Java s ability to import C functions GNAT comes with over 140 standard libraries These include numeric and string libraries file operations hash tables and sorts If you would rather work directly with Linux C libraries a variety of binding libraries exist available for download from the Public Ada Library or The Home of the Brave Ada Programmers These include bindings for POSIX that is the Linux kernel X Windows Motif TCL and WWW CGI applications The Ada Linux Team prepackage many bindings for use with their version of the Gnat compiler More and more Linux libraries feature Ada bindings including ncurses a standard text screen drawing library and GTK the Gimp Toolkit a graphics package Although gnat is distributed under the GPL license gnat and its libraries may be used in commercial applications The GtkAda mailing list is at http gtkada eu org The Gnat mailing list is at http www diax ch users gdm gnatlist htm The Gnat Glade chat mailing list is at glade chat act europe fr 1 4 Why Ada and Linux
206. calls and convert between Ada and C data types For maximum speed and flexibility you can only work with kernel but then you risk extra work by rewriting subprograms that already exist in the standard libraries file G Linux http www vaxxine com pegasoft people html book 13 html 6 of 15 7 20 2001 11 35 52 AM Big Online Book of Linux Ada Programming 13 Linux Introduction To understand the differences between these layers consider the problem of allocating dynamic memory Usually you allocate memory with the Ada new statement Where does new get its memory It uses the standard C library s malloc function But where does malloc get its memory It gets it from the Linux kernel call mmap memory map The most direct way to get memory and the method that gives you the most control is mmap On the other hand the easiest way would be to use new and to let Ada allocate the memory and manage the details for you It s the same with multithreading and sequential files Multitasking is based on LinuxThreads a part of the standard C library which in turn is based on the kernel s clone function Sequential files are based on the standard C library s stream functions which in turn are implemented using the kernel s file handling functions Figure Ways of Doing the Same Thing Memory Allocation Multithreading Sequential Files Standard Ada new task protected Ada Sequential IO package Standard C libraries malloc Linux
207. ce Friendly Ada s readability and scalability make it an ideal language for open source development Child packages for example make it easy to extend someone else s work without affecting the original source code 1 5 Linux Ada Resources There are a variety of resouces on the Internet for Linux Ada development One important resource is the comp lang ada newsgroup which is frequented by many Ada celebrities including Robert Dewar of Ada Core Technologies and Tucker Taft the principle designer of Ada 95 If you have questions about the inner workings of Ada 95 this is the place to go Ada Linux Team ALT is a group of programmers dedicated to Linux programming specifically using Ada This site is located at www gnuada org alt html They provide the latest versions of software and libraries for Linux including bug fixes for Gnat prepackaged and ready for installation The GNU Ada site www gnuada org is a site for all things related to Gnat not only Linux Gnat development The Ada Source Code Treasury at www adapower com provides examples of both Linux and Windows Ada applications Included are examples of sockets MD5 encryption and packages to work with Windows servers from a Linux computer It also has a free unsupported binding to Motif by Itermetric A vestar If you are looking for general algorithms and source code examples PAL the Public Ada Library is a large source code repository located at www monmouth edu facult
208. ch lets you set up callbacks if necessary and returns the number of the control which terminated the dialog 5 2 5 Other Useful Window Manager Subprograms Windows can be saved using the SaveWindow command and loaded again using LoadWindow When a window is loaded with LoadWindow you don t need to open the window or set up the controls the Window Manager does this automatically for you ShellOut will close the windows run a shell command and reopen the windows RefreshDesktop will redraw all the windows on the screen SetWindowTimeout will set a default control to be selected if there is no response after a certain amount of time 15 2 6 Alerts Alerts are small windows that show a short message NoteAlert displays a message with an OK button The status sound is played if installed CautionAlert displays a message with an OK button The text is drawn to emphasize the message The warning sound is played if installed StopAlert displays a message with an OK button The text is drawn to emphasize the message The warning sound is played if installed YesAlert display a message with yes default and no buttons Plays an optional sound NoAlert display a message with yes and no default buttons Plays an optional sound CancelAlert display a message with cancel button and a customized button default Plays an optional sound on YesCancelAlert display a message with yes no and cancel bu
209. characters plus a null character but the array being assigned to is 80 characters You can get around these kind of errors with dynamic allocation The following program demonstrates some of the types and functions in the Interfaces C packages with text_io unchecked_deallocation Interfaces C Extensions use text io Interfaces C interfaces C Extensions procedure ctest is EIN ESI ES pointer to C string and deallocation procedure for same file G Linux http www vaxxine com pegasoft people html book 17 html 1 of 11 7 20 2001 11 37 38 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada type stringptr is access all char_array procedure free is new unchecked_deallocation char_array stringptr types from standard Ada package Interfaces C aL Ine integer u unsigned unsigned integer 1 ESI YO Lola ul unsigned long unsigned long char a Character SP 8 Eneielinejoc r ptr to a string array of characters E 2 C float a float as double a double We wchar_t 16 bit wide character additional types from Gnat package Interfaces C Extensions kong C ORN LONG kone ull unsigned_long_long unsigned long long Vio 2 void ptr void pointer begin Put_Line This is an example of Interfaces C New_Line So new Char array To CX SEPT SESS Seve
210. ching for with new text Select cancel to erase the find text Next Next finds or finds and replaces the next occurrence of the text in the source code If the text is not found TIA beeps Next Err Moves the cursor to the location of the next error and displays the error message at the bottom of the screen Goto Moves the cursor to a specific line 3 1 6 The Misc Menu Edit Macros Brings up the macro edit screen Macros are keyboard short cuts you define Each macro must fit on a line The first character on the line is the trigger and the remaining characters are the keyboard keys the trigger represents For example a line pprocedure defines a macro p that represents the keystrokes p r o c e d u r and e To use a macro in TIA press control A and then the letter of the macro Options Opens the options window The first option is to allow background updates Turn this option off on slow machines The second option sets the background colour to blue or black on colour displays Debugger Runs TIA s ddd style debugger Expand KB GDB This item runs the gdb debugger file G Linux http www vaxxine com pegasoft people html book 3 html 4 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s 3 1 7 The Project Menu Project Params The project parameters window Choose the debugging level CPU type and optimization level and TIA will pass the infor
211. cial or ordinary file mlock disable paging for some parts of memory mlockall disable paging for calling process mmap map files or devices into memory file G Linux http www vaxxine com pegasoft people html book 99_c html 2 of 5 7 20 2001 11 39 50 AM Big Online Book of Linux Ada Programming Appendix C modify ldt get or set dte mount mount and unmount filesystems mprotect control allowable accesses to a region of memory mpx unimplemented mremap re map a virtual memory address msgctl message control operations msgget get a message queue identifier msgrcv receive a messsage msgsnd send a message msync synchronize a file with a memory map munlock reenable paging for some parts of memory munlockall reenable paging for calling process munmap unmap files or devices into memory nanosleep pause execution for a specified time nfsservctl syscall interface to kernel nfs daemon nice change process priority oldfstat obsolete oldlstat obsolete oldolduname obsolete oldstat obsolete olduname obsolete Open open a file or device CUED OUuEW outl pone output macros pause wait for signal personality set the process execution domain pipe create pipe poll wait for some event on a file descriptor protl operations on a process prof unimplemented ptrace process CIC query module query the kernel for various bits pertaining to modu
212. cit length value T Please type in a string of any length Mary had a little lamb The string you typed was Mary had a little lamb It is 22 characters long The third function is a version of Get_Line that reads any string from a Text_IO files 12 3 Sequential IO A sequential file is a list of similar items saved on a disk or other long term storage media They are similar to a one dimensional array except there is no upper bound and each item must be processed in sequence hence the name sequential You can create sequential files of same length strings or integer but most commonly records are used You can open an existing sequential IO file or you can create a new one When you open or create a file you have to indicate what file mode you ll be using In mode files can only be read Out mode files can only be written to Append is like out mode except that records are added to the end of an existing file The reset procedure changes to a new mode and repositions your program accordingly to the end or beginning of the file When you are finished with a sequential file you can either close it or delete it if you don t need it again Because there is no way of knowing how many records are remaining in the file there is a function called End of File that you can check after each read to see if the last item has been read You can only use End of File in In mode it makes no sense to use it in Out or Append mode
213. ck playinfo end_index octl playitrkind ioctl result cg when 2 gt ioctl_noparam ioctl_result exit when others gt Put_Line Pardon end case if ioctl resul 0 then First track 0 no effect 9 final track inclusive OF no er hect CDROMPLAYTRKIND playinfo cd eDROM SiO 7 dummy perror Error controlling CDROM drive J end if end loop Cillose ila Cl Close close_result if close_result lt 0 then perror sees rowe Controlling SiC DIETO IE te he ssi e n end if end audiocd DROM device cao 13 6 Standard Input Output Error Linux defines three default I O streams Standard input Linux file id 0 is the file form which all keyboard input normally comes to your program Standard output Linux file id 1 is the default where the output of your program is written Standard error Linux file id 2 is the file to which error messages are written Usually standard input is from the keyboard and standard output and error are directed to the screen There are two output streams so that if you redirect the results of a command to a file such as Is gt temp out any errors that occur will still appear on the screen The following program writes messages to standard output and standard error using Text IO with ada text io use ada texi procedure si eOr tderr is an example of writing me
214. ckage before it s actually used In this case we don t need one Package specs may have private sections at the end of the spec There will be times when you will have to provide information so that Ada can compile your spec but you don t want the application programmer to be able use this information For example you might create a package to maintain a customer list but you don t want the programmer to access the internal fields of a customer list since you might change them at some point Just about anything in a package spec can be marked private and the compiler expects the details to be specified in the private section Declarations can also be limited private meaning that besides having the details inaccessible to the programmer the programmer can t assign between variables of the type For example use limited private if you think you may include pointers in the type at some time in the future package CustomerList is type aCustomerNumber is new positive range 1 1000 type aCustomerList is limited private private type aCustomerArray is array aCustomerNumber of string 1 120 type aCustomerList is record CurrentCustomer aCustomerNumber Customers aCustomerArray end record no pointers yet but we may some day so it s limited private end CustomerList In this example a programmer can declare customer lists but he cannot access the fields CurrentCustomer or Customers because it s private nor can he copy
215. collection chunk size is amp productCollection Chunk Size products img p product e ol ec some mirst products Put Line The first item is amp p id img p productCollection Last produces Put_Line The last item is amp p id img New_Line Adding another Item perdi 732 p weight 27 0 productCollection Append products put line Produce idt e p idiimg amp Twas added Put Line The collection is empty amp productCollection Is Empty products img Put_Line The collection Tengen is amp produceCollecrion lengen products amer Put_Line The collection chunk size is amp productCollection Chunk_Size products img p productCollection mirst productes 8 B t Line Urbe first icem is Ve p id img p productColllection Last products Put_Line The last item is amp p id img New_Line Changing the Chunk Size Tora olleceineeei ee mismo ze products size gt 1 file G Linux http www vaxxine com pegasoft people html book 18 html 14 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures Put_Line The chunk size was reduced to only 1 Put Line The collection is empty amp productCollection Is Empty products img Put Line The collection length is amp productCollection L
216. collection is empty FALSE The collection length is 1 The collection chunk size 15s 100 the first item as o The last item is 8301 Product id 1732 was added The collection is empty FALSE Booch components collections newly declared with a chunk size of 100 file G Linux http www vaxxine com pegasoft people html book 18 html 15 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures The collection length is 2 The collection chunk size is 100 The first item is 8301 The last item is 1732 The chunk size was reduced to only 1 The collection is empty FALSE The collection length is 2 The collection chunk size is 1 The first item is 8301 The last item is 1732 Resetting the iterator The current item is customer id 8301 Are we done FALSE Advancing to the next item The current item is customer id 1732 Are we done FALSE Advancing to the next item Are we done TRUE BC NOT_FOUND exception no item at this position in the collection 18 1 8 Queues Queues are a list in which items are removed in the same order they are added Items are added at the end of the queue and removed at the front An ordered or priority queue is a queue in which added items are sorted The queues package provides the following subprograms Clear Remove all items from the queue Append Add an item to the
217. com body html marginheigh EQUIV REFRE ton com rev made gt FRAMEBORDER 0 FRAMESPACING 0 BORDER 0 gt name menu frameborder 0 marginheight 0 scrolling auto border 0 gt name body frameborder 0 5 marginwidth 0 noresize scrolling auto border 0 gt SH CONTENT 0 URL body html gt Ff text 000000 gt Ue Tore de here 7a Closing the connection Demonstration finished have a nice day 16 24 Memory Management type aProtection is new integer type aMapFlag is new integer function getpagesize return long integer pragma import C getpagesize Ve file G Linux http www vaxxine com pegasoft people html book 16 html 45 of 47 7 20 2001 11 37 17 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Return the size of a Linux memory page that is the size of the memory blocks that your program and data are broken up into when loaded into memory function mmap start system address size long_integer prot aProtection flags aMapFlag fd integer offset long_integer return system address pragma import C mmap Allocates size bytes of memory and returns a C pointer If it failed 1 is returned If MAP_FIXED and start are used the memory will be at the specified address The protection flags indicate how the memory will be accessed a signal will be raised on
218. com pegasoft people html book 14 html 6 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming procedure HandleControlC pragma Attach_Handler HandleControlC SIGINT SIGINT Control C signals will be intercepted by Handileconte role procedure HandleKill pragma Attach Handler HandleKill SIGTERM SIGTERM kill command signals will be intercepted by gt HandiekKuli procedure HandlePowerFailure pragma Attach Handler HandlePowerFailure SIGPWR SIGPWR power failure signal intercepted by HandlePowerFailure end SignalHandler end SigHang with Ada Text IO use Ada Text IO package body SigHand is Package to handle basic Linux signals protected body SignalHandler is This protected type contains all our signal handlers procedure HandleControlC is Control C signal Handler begin if EMERGENCY SHUTDOWN then Put Line HandleControlC The program is already shutting down else Put Lane HandleControlC Control C was pressed shutting down j end if EMERGENCY SHUTDOWN true end HandleControlC procedure HandleKill is normal kill signal handler begin if EMERGENCY SHUTDOWN then Put Line HandleKill The program is already shutting down else file G Linux http www vaxxine com pegasoft people html book 14 html 7 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Progr
219. const Struct nr route struct SIOCGIFCONP takes a struct itcont The irc buf field points to a buffer of length ifc_len bytes into which the kernel writes a list of type struck arr eq SIOCSIFHWADDR takes an input pointer whose type depends on the protocol Most protocols consc struct itr eg AZ Const envie oe ADDR LEN TIOCLINUX takes a const char It uses this to distinguish several independent sub cases In the table below N foo means foo after an N byte pad struct selection is implicitly defined in TIOCLINUX 2 1 Const Struct selection TIOCLINUX 3 void TIOCLINUX A4 void TIOOGLINUX S 4 const struc 43 dome e p TIOONINUX S char TIOCLINUAeT char TIOCLINDUX LHO d a gt cConsic char v Duplicate ioctls This list does not include ioctls in the range SIOCDEVPRIVATE and O TOCPROTOPRRIVATHKE 0x00000001 FDSETPRM FIBMAP 0x00000002 FDDEFPRM FIGETBSZ 030000559682 CDROMAUDIOBUFSIZ SCSI_IOCIL GET IDLUN file G Linux http www vaxxine com pegasoft people html book 99_e html 14 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E 0x00005402 SNDCTL_TMR_START TCSETS 0x00005403 SNDCIL IMR STOP TCSETSW 0x00005404 SNDCTL TMR CONTINUE MOSENSE lt Appendix D Table of Contents Appendix F gt file G Linux http www vaxxine com pegasoft people html book 99_e html 15 of 15 7 20 2001 11 40 32 AM Big Online Book of Li
220. cord cr name Tokyo Book Distributors ur Write CustomerFile cr P t _lLine Writing amp ees iate J write another record cr name General Pizza Inc E Write CustomerFile cr Put Line Writing amp cr name Put Line End of File not allowed on Out files begin if End Of File CustomerFile then Put Line We are at the end of the file else file G Linux http www vaxxine com pegasoft people html book 12 html 9 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages Put_Line We aren t at the end of the file end if exception when Ada IO Exceptions Mode Error gt Put Line Standard Error End_of_File caused Ada IO Exceptions Mode_Error when others gt Put_Line Standard_ Error end New_Line change modes using Reset Unexpected exception occurred Put Line Reset can change the file mode Put Line Changing to In File mode Reset CustomerFile In File read first record Jur Put Line Reading the next customer Read CustomerFile cr Put Line Read amp cr name New Line fead second record We Put_Line Reading the next customer Read CustomerFile cr Put_Line Read amp cr name New_Line check the end of the file Put Line End of File works if End Of File CustomerFile f on in files
221. cord hourlyRate float end record A tagged record extended in this way has all the fields of anEmployeeProfile but has the additional field of hourlyRate anEmployeeProfile and anHourlyEmployee are said to be in the anEmployeeProfile class the class is the collection of anEmployeeProfile and all record extended from it Now we can create a access type commonly called a pointer though technically it isn t a pointer to any record in the class type anEmployeeProfilePtr is access all anEmployeeProfile class This pointer can be assigned either anEmployeeProfile record or anHourlyEmployee record This is the purpose of the tagged record s invisible tag The tag indicates the type of tagged record a pointer points to since these kinds of pointers can refer to more than one type of tagged record This is sometimes called late binding ptrl anEmployeeProfilePtr new anEmployeeProfile Bob Smith 45 ptr2 anEmployeeProfilePtr new anHourlyEmployee Denise Jones 37 17 50 Access variables are null until assigned a different value They are the only variables in Ada to have a default value There may be cases where you want to extend a type without adding new fields Ada provides a shorthand phrase for this For example if you want to distinguish hourly employees that work at night as being separate from other hourly employees use type aNightHourlyEmployee is new anHourlyEmployee with nul
222. cord or tagged record to illegal values wherever possible This pragma helps expose variables used before they are initialized Use this at the start of a program or package Suppose you have a integer variable with a range between 1 and 100 Normally Ada won t assign an initial value unless you specify one With Normalize Scalars your variable will be initialized to some value out of range perhaps 1 If you attempt to use this variable you ll probably raise a CONSTRAINT ERROR exception 8 3 Identifying Files Rewrite and Expand From Usenet gt If you are using 2 2 x you can use the proc to find a process which is using a directory or file If is the case try this Is lad find proc grep home The number after the proc should be the process ID gt gt Any way it seems a little bit delicate umount your home after the boot Couldn t you use a rescue disk and format your home without mount it in a boot gt gt Are you sure your home isn t only a part of your root directory When you type df does it report a different device for the home gt Sorry if I m asking a very basic question gt try fuser or Isof 8 4 Compiler Info with gnatG The gnatG compiler switch shows Gnat s interpretation of your source code after its initial analysis If you specify gnatD Gnat will write this information to a file ending in dg for debug The following is a listing of the pointers program used later in this bo
223. cture can be made guarded using guarded containers but in some cases guarding will not work as expected and should not be used for example with lists The basic semaphore locks individual objects although it many not work as expected on certain structures such as lists according to AdaPower Net The basic semaphore can be extended and customized by a programmer Rewriting the Bags example with guards with BC Containers Bags Unbounded with BC Containers Guarded with BC Support Synchronization with Global_Heap package guarded_customers is type aCustomerID is new integer range 1 000 9 999 function IDHash id aCustomerID return Positive obe hash a Umer atom file G Linux http www vaxxine com pegasoft people html book 18 html 25 of 26 7 20 2001 11 38 19 AM Big Online Book of Linux Ada Programming 18 Data Structures package customerContainers is new BC Containers Item gt aCustomerID this is the basic container package customerBags is new customerContainers Bags create a new bag support for our using container type package customerBag is new customerBags Unbounded Hash IDHash Buckets gt 99 Storage_Manager gt Global_Heap Pool Storage gt Global Heap Storage create an unbounded bag holding customer numbers package customerGuardedBag is new customerContainers Guarded Base_Container gt customerBag Unbounded_Bag
224. cular address using for var address clause Together with size you can theoretically refer to an bit in the computer s memory However on Linux the address refers to a location in your address space and doesn t refer to a real physical location var alignment will align storage to a particular byte boundary var bit order can specify a different bit order for a record than the default for your machine The bit orders are defined in the System package Gnat 3 12 doesn t fully support bit orders for Reg address use 16 2EF hex address 2EF in your memory space for Reg alignment use 2 align to 16 bit boundaries for myRecord bit order use system low order first low bits to high machine If the register value can change independently of the Ada program usually true we need to mark the pointer with pragma volatile to make sure the compiler will make no assumptions while optimizing pragma volatile RegPtr Ada will do bit wise logic operations but it will only do them on packed arrays of booleans or modular types You can t do bit wise operations on integers for example The bit wise operators are and or xor and not type byte is array 1 8 of boolean pragma pack byte DIP E27 BOn byte bs pl and p2 If you need octal or hexadecimal numbers Ada denotes these by using a leading base designation between 2 and 16 with the value delimited by number signs Hex 16 0FE9 Bin 24011010105
225. cumentation is available from the mySQL web site 16 14 2 PostgreSQL Not finished K B 16 15 Dynamic Loading Not finished K B 16 16 A Word on Device Drivers The details of writing kernel device drivers in Ada is beyond the scope of this book However you ll have to use GNORT pragma no run time with Ada Text IO use Ada Text IO procedure nrt2 is Simple Program begin file G Linux http www vaxxine com pegasoft people html book 16 html 30 of 47 7 20 2001 11 37 16 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming put_line Hello World end nrt2 pragma no run time procedure nrt is Same as nrt2 but using no run time type file id is new integer No Ada Text IO possible so we ll write our own that talks directly to the Linux kernel procedure write char amount written out long integer id file_id buffer in out character amount2write long_integer pragma import C write_char write pragma import_valued_procedure write_char write procedure put c character is result long integer PUF lt Character C begin write_char result 1 buf 1 end put procedure new_line is begin put character val 10 end new_line procedure put line s string is pragma suppress index check s s i won t throw a range error but Gnat checks for it by default Exceptions are a par
226. d length e Copy Copy one stack to another Stacks can be bounded dynamic or unbounded Stacks are used for temporary storage compact representation and fast data access 18 1 10 Deques Deques double ended queues pronounced deck are a combination of a stack and queue where items can be placed at the front or the back and removed from either the front or the back The Deques package provides the following subprograms Clear Remove all items from the deque Append Add an item to the deque Pop Remove an item from the deque and return it Remove Remove an item at a particular index Length Return the number of items in the deque Is Empty True if there are no items in the deque Front Return the item at the front of the deque without removing Back Return the item at the back of the deque without removing it Process Front Back generic procedure to return an item with processing Location Return the first index where an item appears else 0 Are Equal True if two deques have the same items and length Copy Copy one deque to another Deques can be bounded dynamic or unbounded 18 1 11 Rings Rings are similar to deques but rings have no front or back only a moving point of reference called top In addition to the deque subprograms rings include Mark to mark a point in the ring Rotate To Mark to move the ring to the marked position and At Mark to test to see if the top of the ring is at the mark
227. da Programming Appendix B ETME meexied IENOSR J 8 Out of streams resources ENONET M Machineis not on the network ENOPKG Package notinstalled IEREMOTE joe Objectis remote IENOLINK 67 Link has been severed EADV 68 Advertise error ESRMNT 69 Srmount error IECOMM po Communication error on send EPROTO 1 Prmtcoemr EMULTIHOP 2 Multihop attempted IEDOTDOT 3 RES specific error IEBADMSG 4 Neadaamesag IEOVERFLOW 5 Value too large for defined datatype ENOTUNIQ 6 JJNamenmeuniqeonnetwok EBADFD 7 Fille descriptor in bad state IEREMCHG 8 Remote address changed ELIBACC 9 Cann not access a needed shared library ELIBBAD B0 Accessing a corrupted shared library ELIBSCN Jibsecioninaoutcomupted ELIBMAX 8 Linking in too many shared libraries ELIBEXEC 8B3 Cannot exec a shared library directly EILSEQ 4 egal byte sequence ERESTART 85 Interrupted system call should be restarted ESTRPIPE 56 Streams pipe error EUSERS 51 Tomayvues ENOTSOCK 88 Socket operation on non socket EDESTADDRREQ 89 Destination address required EMSGSIZE po Message toolong
228. defined in the Init procedure When a radio button is turned on all other buttons in the family are turned off WindowButton Loads a window from disk and displays it The window must have been saved with the Window Manager s SaveWindow procedure Rectangle A box which can be drawn around controls Line A line what else would it be drawn between two corners of the enclosing rectangle defined by the Init procedure HorizontalSep A horizontal line often used to separate controls into groups VerticalSep A vertical line often used to separate controls into groups StaticList A scrollable box of unchanging text file G Linux http www vaxxine com pegasoft people html book 15 html 8 of 13 7 20 2001 11 36 38 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings CheckList A scrollable box of check boxes RadioList A scrollable box of radio buttons EditList A scrollable box of editable text SourceCodeList used by PegaSoft s TIA A scrollable box containing source code OS Package This package contains various calls for working with the operating system All calls support path prefixes as described above Here are some of the subprograms UNIX run a UNIX shell command The function variations return the result of the command Runlt runs a UNIX program ValidateFilename check for a syntactically correct filename NotEmpty true if a file is not empty IsDirectory true if fi
229. dentical processes put SI cl LLL LLL LL LUI LE v gs myPID fork solit in tyo This program is now the original process or the file G Linux http www vaxxine com pegasoft people html book 16 html 10 of 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming new child process myPID tells you which process you are if myPID lt 0 then Put Line Standard Error Fork has failed Error code amp errno img elsif myPID 0 then Put Line This is the child process else Put Line This is the original process gt wait until child as finished wait wait pid wait status if wait pid 0 then Put Line Standard Error Wait error wait returned PID amp wait pid img amp and error number amp errno img end if end if end multitask Welcome to this multitasking example This is the original process Splitting into two identical processes This is the original process This is the child process 16 7 Linux File Operations The Linux file operations are part of the standard C library and don t need to be linked in with the lc option The C calls are defined in the fcntl h header file Explain Linux files here Linux never shortens files If your file gets smaller you must shorten it yourself using Eruncate The following bindings assume these types have been defined type
230. depending on what you are trying to accomplish Variant records tend to be smaller and faster but are harder to extend than tagged records Since tagged records are naturally used to create variables that are similar to one another you might wonder if you d ever create a single variable of a tagged record type These are called singletons and are used in frequently in languages like C They are popular because they have a specific elaboration order and provide access to features only available in objects such as private members Programmers doing this have no need to create a class of several objects However Ada has an easily controlled elaboration process and features such as privacy are not specific to tagged records As a result there is rarely a need for singletons in Ada programs 11 8 Exceptions Ada Description CC Equivalent le exception Declare an exception f raise e JRaisethrowanexception throw type exception clause Handlecathanexcepion try catch C In C exceptions are performed by throwing types typically objects In Ada an exception is a separate type Only exceptions can be thrown you can t throw types Exceptions aren t related to objects in any way When you throw in C you do so in a try block In Ada you can throw an exception in any block The exception clause equivalent to catch at the end of the block is optional file G Linux http www vaxxi
231. der IDE TIA supports make To use make select it in the project parameters window Gnatmake is the best tool for building small projects However if you have a lot of C functions you may want to use Linux s traditional project building command make The make command interprets a series of rules saved in a file called Makefile These rules describe which files are dependent on which other files Each rule is followed by the command needed to update the files such as the command to compile them For example if you had a Ada program called dbase and it relied on the source files common adb scanner adb and parser adb a Makefile might include the rule dbase common o scanner o parser o gnatlink o dbase This rule says that the dbase executable file depends on the object files for the 3 Ada source files and to update dbase make has to link the object files with the gnatlink command If you are writing an Ada program with C source files the basic strategy for using make with gnat is to make rules than ensure the C files are compiled properly and then to finish the project using Gnatmake Makefiles can have comments and variables and rules that refer to parameters to the make command as opposed to files The many options can t be covered here 5 1 1 A Simple Ada Makefile The following Makefile will compile an Ada program called main adb plus any packages used by main This should work for most small projects Edit the OBJS
232. dled before others The final or part of a select can contain instructions to execute when none of the accepts statements are executed For example a task can end itself with the terminate command If you want a task to terminate when there are no more requests add a or terminate at the end of your select statement If select statement doesn t give you enough control over blocking select can include when clauses The clauses work like an if statement executing the accept statement only if a condition is true If time2accept is a boolean variable you could write select when time2accept gt accept add amount integer do A when clause is referred to as a guard because like a crossing guard the accept will not execute unless the guard gives permission Ada also has a delay statement Delay forces a task or a program to suspend itself for a number of seconds To wait for three and a half seconds use delay 3 5 You can place a delay statement in the last or part of a select statement to force the task to suspend itself for a few seconds if no requests were found file G Linux http www vaxxine com pegasoft people html book 1 1 html 24 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Delay can also wait for a particular time The time is expressed using the Ada Calendar time format If Tomorrow is a variable with the time of midnight tomorrow in the Ada Calendar
233. dure simple procedure function simple function return boolean end tiny You can create a stub body for this package using gnatstub tiny ads Gnatstub produces the following tiny adb file package body tiny is function simple function return boolean is begin return simple function end simple function file G Linux http www vaxxine com pegasoft people html book 6 html 1 of 14 7 20 2001 11 31 53 AM Big Online Book of Linux Ada Programming 6 Development Utilties simple procedure procedure simple procedure is begin null end simple procedure end tiny This package body is in proper Ada format ready to be compiled Of course it doesn t actually do anything useful It s up to the programmer fill in the implementation details 6 2 Cross referencing with Gnatxref Gnatxref or gnatf in gnat 3 10 is a utility that produces an index of every occurrence of an identifier in a program including all identifiers used by packages that the program depends upon The v option produces a listing in the format for a vi editor tags file IDE TIA will run gnatxref on the current file by chosing Xref in the File menu For our hello adb program Gnatxref produces the following Text roO U a textio sads 51 13 helLlo adb 1 10 4 7 Put_Line U a textio ads 260 14 hello adb 4 15 Ada U ada ads 18 9 hello adb 1 6 4 3 hello U hello adb 2 11 Each line begins with the identifier being index
234. dvanced Linux Programming 16 9 Directories Directories are folders containing collections of files and other directories In Linux a directory is a special kind of file Some of the standard file operations work on directories and some other file operations are specific to directories The top most directory is or the root directory All files on a system are located under the root directory Disk drives do not have separate designations as in MS DOS A period represents the current directory and a double period represents the parent directory of the current directory All directories have and defined The root directory of course doesn t have a parent it s entry points to itself Many of the kernel calls and standard C library functions dealing with directories use functions that return C pointers As mentioned in the bindings section the only way to convert these kind of functions to Ada is by declaring the C pointers as a System Address type and changing the C pointers to Ada access types using the Address_To_Access_Conversions package procedure getcwd buffer out string maxsize size_t pragma import C getcwd Returns the name of the current working directory as a C string in buffer Maxsize is the size of the buffer All symbolic links are dereferenced function get_current_dir_name return System Address pragma import C get_current_dir_name Like getcwd returns the current working directory
235. dy customers function IDHash id is aCustomerID return Positive is our hash tumetd on begin return Positive id in this case using the id is good enough end IDHash end customers with ada text io BC customers use ada text io procedure bag demo is ustomers customers customerBag Unbounded Bag aCustomerID i customerContainers Iterator class customerBag New_Iterator Customers begin Put_Line This is a demo of the Booch components bags New_Line The Newly Declared Bag Put_Line The bag is newly declared Put_Line The bag is empty amp customerBag Is Empty customers img Put Line The bag extent is amp customerBag Extent customers img Put Line The bag total size is amp customerBags Total Size customers img New Line Inserting a customer cC i 7456 customerBags Add customers c Put Line Added customer amp c img Put Line The bag is empty amp customerBag Is Empty customers img Put Line The bag extent is amp customerBag Extent customers img New Line Inserting another customer C 93 62 customerBags Add customers c Put Line Added customer amp c img Put Line The bag is empty amp customerBag Is Empty customers img Put Line The bag extent is amp customerBa
236. e Gnat defaults sieaa ENAT Heap Sora Heapsort package using access uU types g hesorg IGNAT Heap Sort G Generic heapsort package E g htable IGNAT HTable Generic hash table package GNAT IO Text I O for preelaborated packages Get Line functions and file E existence test for Text IO Package for locking g locfil GNAT Lock Files files directories with retry capability os lib GNAT OS Lib Package for common Linux B08 _ O S operations Simple package for Linux g regexp GNAT Regexp globbing pattern matching and Ada BNF Package providing full UNIX g regpat GNAT Regpat regular expression pattern matching Check for a typo similar to g speche ONAT SpelL Checker E To Of a Teaio es providing SPITBOL g spipat GNAT Spitbol Pattern ut SPITBOL string processing g spitbo GNAT Spitbol MM NM g sptabo IGNAT Spitbol Table Boolean Boolean type SPITBOL table g sptain IGNAT Spitbol Table Intege Integer type SPITBOL table file G Linux http www vaxxine com pegasoft people html book 99_f html 7 of 9 7 20 2001 11 40 56 AM Big Online Book of Linux Ada Programming Appendix F i Unbounded string type g sptavs GNAT Spitbol Table_V String Sern che table GNAT Table Dynamic one dimensional arrays package g tasloc GNAT Task Lock Package for protecting critical regions in tasks g thread IGNAT Threads Import C threads as Ada tasks EUST GNAT Traceback Non symbolic traceback support
237. e OpenGL Mesa Binding Mesa is an OpenGL library for 3D graphics It can create 3D objects transform them and supports accelerated drivers You can use Mesa under GTK by using a GTK GL Area widget and draw graphics inside using Mesa 15 8 Engine 3D Engine 3D is a real time 3D drawing package written entirely in Ada The Linux port is by Duncan Sands The Engine 3D package is at http members nbci com gdemont e3d htm Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 15 html 13 of 13 7 20 2001 11 36 38 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming 16 Advanced Linux Programming lt Last Chapter Table of Contents Next Chapter gt 16 1 Writing Your Own Bindings Ada Packages Description LC Equivalent pragma import import identifier from another language extern is oe a Cl pragma import_function Like import but extra options pragma import_procedure Like import but extra options Import a function that returns values as pragma import_valued_procedure extern parameters pragma export_function Like export but extra options lp ragma export_procedure Like export but extra options Because gnat is tightly integrated with gcc we can make certain assumptions that would otherwise be impossible e the basic Ada data types are equivalent to their C counterparts an Ada in
238. e are on row The file is open Writing Midville Electric There are 1 records We are on row 2 Writing New York Distributors to row 7 There are 7 records We are on row 8 End_of_File not allowed on In files End of File caused Ada IO Exceptions Mode Error Reset can change the file mod Changing to InOut File mode Reading the next customer Read Midville Electric Reading from row 2 Read Reading from row 7 Read New York Distributors Fa End_of File works on InOut files We are at the end of the file Closing file Note In this example reading from the unassigned second record put a row of 40 ASCH NUL characters on the screen Because these are non printable characters nothing is visible in the results What about objects How are tags treated KB Direct_IO files are suitable for small database tables If you need to work with large amounts of data you should consider installing one of the free Linux databases such as PostgreSQL or mySQL and using them to store and retrieve your data This is discussed in upcoming chapters file G Linux http www vaxxine com pegasoft people html book 12 html 14 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages Alternately you can write your own database package using a the Linux kernel seqio a sequential IO package is developed in chapter 16 12 5 Formatted Outp
239. e code instructions However binary files are more than just raw microprocessor instructions They contain information such as the type of the binary file and a list of all DLL s needed by the program to run Linux binary files come in two formats ELF Executable and Linking Format and a out They both have different characteristics and neither is better than the other Most distributions let you install ELF or a out compilers The version of gnat for Linux is compiled for ELF ELF is current Linux standard primarily because it provides better support for shared libraries Fun Fact a out is an abbreviation for assember output Since the kernel has to do the loading and execution of programs support for ELF a out or both must be selected when the kernel is compiled Otherwise the kernel will not recognize the format and will be unable to run the binary file 13 9 Linux Libraries A library is a set of object files that have been combined into a single file You create a Linux library using the ar archive which takes o object files can compiles them into or out of a archive file A Linux library files all start with lib and end with a The command parameters for ar are a bit odd check the man page for more details The ar comamand has many options Two useful variations are ar cr create a new archive and add object files to it and ar t show a list of all object files in the archive file See the example below for how these
240. e computers should be set identically or cook may be confused by the age of the files To cook in parallel run cook with the par switch This option indicates the number of computers cook can use the default being 4 You can indicate fewer computers For example par 2 will run cook using 2 computers To indicate which machines to use assign the hosts to the parallel_hosts variable parallel_hosts first_computer second_computer third_computer Simple Howto cook files will compile in parallel without any modification 5 2 2 A Simple Ada Cookbook The following Howto cook file will compile an Ada program called main adb plus any packages used by main This should work for most small projects Edit the OBJS variable to include all the object files from the packages you are using To use this make file type cook to build your Ada project or cook clean to remove any intermediate files produced by the compiler file G Linux http www vaxxine com pegasoft people html book 5 html 3 of 6 7 20 2001 11 31 40 AM Big Online Book of Linux Ada Programming 5 Building Large Projects The ALT version of Gnat uses uses the name gnatgcc not gcc for the GCC compiler e A EE E ee This is a simple Ada Howto cook cookbook a ari it assumes the main program is named z main adb qupd a t oy Ken Burtch s IEEE x sr OBJS main o somepackage o How to compile individual Ada files S 0 aadb
241. e just saved Reraise Occurrence saved exception Allocate DeallocateMachineState not covered for zero cost exceptions end exc This is an example of the Ada Exceptions package Exception Name returns a unique name for an exception The unique name our exception is EXC E raise will raise an exception with no message Raise Exception will raise an exception with a message Raising EXC E with the message call exc development team in the subprogram CrashMe An exception has been raised Now in exception handler The name of the exception is EXC E Exception Message returns the message for this exception The message for this exception is call exec development team E od Exception Information provides the name message and any traceback information Exception name EXC E Message call exec development team The Gnat Current Exception package contains short hand versions of Exception Name Exception Message Exception Information These functions assume you re referring to the current exception Gnat Current Exception Exception Name is E Gnat Current Exception Exception Message is call exec development team The Gnat Traceback Symbolic package returns the contents of the file G Linux http www vaxxine com pegasoft people html book 12 html 34 of 35 7 20 2001 11 34 28 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages ru
242. e made to the file since checking it out armitage home ken ada rcs rcsdiff f c RCS file RCS f C V retrieving revision 1 1 file G Linux http www vaxxine com pegasoft people html book 9 html 2 of 6 7 20 2001 11 32 37 AM Big Online Book of Linux Ada Programming 9 Team Development Gift ril ll I C Oal gt test line Finally you can check the file back in RCS increments the version number and prompts you for a message for the change log armitage home ken ada rces ci f c RCS f c v f c new revision 1 2 previous revision 1 1 enter log message terminated with single or end of file gt gt Added comments gt gt done 9 3 CVS Concurrent Versions System CVS Concurrent Versions System is a front end to RCS designed to work with groups of files in multiple directories CVS can work with individual files whole directories or you can organize large projects into groups of files called a modules that you want to work with Like RCS it timestamps files maintains version numbers and identifies possible problems when two programmers update the same section of a program simultaneously CVS is very popular for open source development CVS can be configured to allow programmers all over the world to work on your project without having to be logged into your computer In order to use CVS the project leader needs to create a directory for CVS to work in called
243. e pending signals sigprocmask change blocked signals Sigreturn return from signal handler and cleanup stack Sigsetmask set net group of blocked signals sigsuspend replace signal mask and suspend process sigvec obsolete file G Linux http www vaxxine com pegasoft people html book 99_c html 4 of 5 7 20 2001 11 39 50 AM Big Online Book of Linux Ada Programming Appendix C socket create an endpoint for communication socketcall socket system calls entry point SOCketpair create a pair of connected sockets ssetmask NQS stat get file status statfs get file system statistics stime set time stty unimplemented swapoff stop swapping to file device swapon start swapping to file device symlink make a new name for a file syne commit buffer cache to disk sysctl read write system parameters sysfs get file system type information sysinfo returns information on overall system statistics syslog read and or clear kernel message ring buffer set console loglevel time get time in seconds times get process times truncate truncate a file to a specified length umask set file creation mask umount unmount filesystems uname get name and information about current kernel unlink delete a name and possibly the file it refers to uselib select shared library ustat get file system statistics utime change access and or modification times of an inode
244. e same time There s two ways to do this e Use the standard C function tmpfile discussed below e Find the process number of your program with the standard C function getpid and add it to your filename If you are interested in accessing Linux more directly read the next section 13 3 The Linux Environment Because Linux is based on decades old UNIX the Linux development environment is like an onion Originally all UNIX programs accessed the operating system through kernel calls As time went on new ways of accessing the kernel were added and new libraries were made to encapsulate common problems Finally Ada itself comes with many standard packages and features to work with the operating system For the Ada programmer it s not difficult to work with the operating system Gnat comes with many standard libraries These are built using the standard C libraries The C libraries in turn work by accessing the kernel The problem is to decide which of the many ways to access Linux is the best suited for your program For simple tasks using the standard Ada packages is the most straightforward way of working with Linux However the standard Ada packages were designed for portability they only allow access to the most basic Linux features and they aren t particularly fast when doing it Working with the standard C libraries is a compromise between speed and convenience the C libraries give you more features but require you to import C function
245. e version of gcc for gnat has all of the normally document gcc switches plus some new switches for gnat You can run gcc by itself or have gnatmake run gcc for you Unless otherwise noted these switches can be applied to both gcc and gnatmake b For crosscompiling compile for a target machine Bdir Multiple gnats load the gnat compiler from directory dir instead of the default one c gcc only tells gcc to compile only and not to try to link with the C linker g create an executable that can be used with the gdb debugger Idir Beside the directory with the first file check directory dir for more source files I Do not look for source files in the directory where the first file resides On On Optimize from 0 none to 3 maximum automatic internal inlining See below s gcc only create an assembly language source file instead of an object file Wuninitialized warnings on uninitialized variables v show what steps the gcc compiler is performing gnata turn on debugging pragmas See below gnatb keep messages brief gnatc check the program but don t compile it gnatdx activate ACT internal debugging switch x where x is a character gnatD with gnatG save debugging info to files ending in dx gnate display error message immediately instead of waiting until end of compile gnatE turn on dynamic elaboration checks gnatf give more information about errors gnatg turn on gnat style checks g
246. ecify which processor will receive a task Linux takes care of this automatically Multithreaded programs have limits on the stack size for each thread this is true for all Linux computer languages Gnat 3 13 has an 8 Meg stack size limit per thread Older versions had limits as low as Meg per thread because of limits imposed by the Linuxthreads library A task can take on several forms In its simplest form a task is structured like a package with a specification and a body The following is an example of a simple thread that waits 5 seconds after a program is started and displays a message file G Linux http www vaxxine com pegasoft people html book 11 html 22 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming task SimpleTask task body SimpleTask is begin delay 5 0 Put_Line The simple task is finished end SimpleTask The specification like a package indicates what identifiers are available to the outside world The SimpleTask thread doesn t communicate with the main program it s specification is only one line long Communicating with the rest of the program can be difficult For example with the tasks and main program running in parallel sharing variables can be difficult How does one task know when another task or the main program is finished changing the value of a variable If a task works with a variable that s only partially been udpated the data will be corrup
247. ed The U means not sure KB The next segment is the file that defines the identifier and the position in the file The means not sure KB The final bracketed section lists all occurrences of the identifier in the program In this example identifier text_io appears in the first line the with and the fourth line the put_line 6 3 Eliminating Dead Code with Gnatelim gnatelim is a utility that searches for unused parts of your program in the object files and removes them from the final executable It works by creating a list of subprograms that the compiler shouldn t compile If you save this list as gnat adc gnatmake will automatically read this file and will skip these subprograms when compiling To use gnatelim you need to generate tree files using the gnatt switch The Gnat manual recommends these steps when using gnatelim assuming that your main program is main adb l gnatmake c main 2 gnatbind main 3 gnatmake f c gnatc gnatt main file G Linux http www vaxxine com pegasoft people html book 6 html 2 of 14 7 20 2001 11 31 53 AM Big Online Book of Linux Ada Programming 6 Development Utilties 4 gnatelim main gt gnat adc 5 gnatmake f main These commands will generate a complete set of tree files for your project strip out all unused subprograms and will then recompile the project as a finished executable gnatelim is is based on ASIS gnatelim doesn t work under gnat 3 11 KB 6 4 Execut
248. ed the Ada file currency adb to it currency adb is now stored in the CVS repository ready to be shared amongst the team members To work with a project you use co or checkout This CVS command will save a copy of the project in your directory It will also create a CVS directory to save private data files used by CVS To use co move to your home directory and type root redbase cvs cvs checkout currency adb cvs checkout Updating U project currency adb The subdirectory project will contain your own personal copies of project files to work on CVS maintains the original copy of currency adb Another programmer can also checkout currency adb while you are working on your copy If you do a checkout right after an import you may have to remove the original files CVS will not overwrite any existing files To add a file to CVS use the add command To add a file called currency adb use root redbase cvs cvs add currency adb Single files directories or even CVS modules can also be added to your project using add As you work on your source code you can check your work against the project using the update command root redbase cvs cvs update cvs update Updating When updating CVS checks the files in your copy of the project against its copies If another team member made changes to one of the project Ada files CVS will copy the new file to your directory If another team member
249. en Ada IO Exceptions Mode Error gt Put Line Standard Error End of File caused Ada IO Exceptions Mode Error when others gt Put Mane Standard Beror Unexpected exception occurred end New_Line change modes using Reset Put Line Reset can change the file mode Put Line Changing to InOut File mode Reset CustomerFile InOut File read first record Pu ut_Line Reading the next customer 5 Read CustomerFile cr Put_Line Read amp cr name New_Line read second undefined record Put Lane Reading from row 2 Read CustomerFile cr Put_Line Read amp cr name New_Line read 7th row Put_Line Reading from row 7 Read CustomerFile cr From gt 7 Put Line Read amp cr name New Line check the end of the file Put Line End of File works on InOut files file G Linux http www vaxxine com pegasoft people html book 12 html 13 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages if End Of File CustomerFile then Put Line We are at the end of the file else Pur Line Wer aren t at the end of the file end if New_Line Put Line Closing file y Close CustomerFile end dirio This is a Ada Direct_IO example We created the file home ada customer dir We re currently using OUT_FILE mode There are O records W
250. eneric package System Address_To_Access_Conversions type intacc is access all integer package strConvert is new System Address_To_Access_Conversions intacc string address strConvert To Address SomeIntAccVar Ada 83 The original use of all created too many ambiguities Ada 95 requires greater use of all 11 10 Callbacks A callback is a pointer to a subprogram They are called callbacks because you usually give the pointer to another subprogram that calls the procedure pointed to whenever it needs to You can declare callbacks using type type UpdateWindow is access procedure type DisplayNewValue is access procedure newval integer One important restriction is that Ada requires that callbacks to refer to global subprograms This is done to ensure that the access variable always points to an existing subprogram You cannot create a callback to a local procedure or function even if it s perfectly safe to do so If you try you ll get an obscure error message about one level being deeper than another The gnat equivalent for unchecked access for callbacks is unrestricted access which you can use if you re absolutely sure the subprogram you re using will not save the access when it s finished running You can get the address of a procedure using access Suppose MyUpdateProcedure is a procedure fitting the description of UpdateWindow a procedure with no parameters updatePtr UpdateWindow MyUpdateProcedure
251. ength products img Put Line The collection chunk size is amp productCollection Chunk Size products img p Bes producteolllection mirst productes P Put_Line The first item is amp p id img p productColllection Last products j Put Line The last item is amp p id img New Line Iterator example Put_Line Resetting the iterator productContainers Reset i p productContainers Current item i Put Line The current item is customer id amp p id img Put Line Are we done amp productContainers Is Done i img Put Line Advancing to the next item productContainers Next i p productContainers Current item i Put Line The current item is customer id amp p id img Put Line Are we done amp productContainers Is Done i img Put Line Advancing to the next item productContainers Next i Put Line Are we done amp productContainers Is Done i img begin p productContainers Current item i exception when BC NOT FOUND gt put line BC NOT FOUND exception no item at this position in the collection end Collections are suitable for small lists or lists where the upper bound is known or rarely exceeded the This is a demo of The The The The is is empty TRUE length is O0 chunk size is 100 Gore isse collection collection collection Product id 8301 was added The
252. ent what the key is Hash HashOf function to generate the hash Equal gt how to compare things in table begin Put_Line This is an example of a hash table of integers New_Line IntTable cet 1 1 J mertaple set C277 27 Put_Line Added 1 and 27 to the hash table Put_Line Empty positions are amp EmptyPosition img New_Line Put Line Pulling 1 from the hash table amp IntTable Get 1 img P t laine Pulling 27 from the hash table amp IntTable Get 27 mie Put_Line Pulling 99 from the hash table amp IntTable Get 99 img end HashTest This is an example of a hash table of integers Added 1 and 27 to the hash table Empty positions are 9999 Pulling 1 from the hash table 1 Pulling 27 from the hash table 27 Pulling 99 from the hash table 9999 Could use more realistic example KB 12 10 Bubble and Heap Sorts Gnat provides two packages for bubble sorting Both assume that your information is in an array with a lower bound of zero The zero element is used as temporary space for the sort The first gnat bubble sort g is a generic You provide the package with a procedure to move data in the array and a function to check for one value being less than another The instantiation provides a sort procedure with text io gnat bubble sort g file G Linux http www vaxxine com pegasoft people
253. enumerated is MEGABYTE The smallest float is 1 17549435082228751E 38 The largest float is 1 93428038904620299K 25 Ihe number of digits in float is 6 The size of the mantissa in bits is 21 However the CPU s mantissa is 24 file G Linux http www vaxxine com pegasoft people html book 10 html 16 of 29 7 20 2001 11 33 06 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada 10 5 Operations and Expressions Ada Operator Description Equivalent and Boolean and amp amp er Boolean or Jd XOr Boolean xor Bo not Boolean not fe E Nocquis n E abs Absolute Value BP mod Integer modulus rem Float remainder fe land then Short circuited and fe or else Short circuited else fe fn Wale in range 7 notin Short for not in O Boolean operations and or not xor Comparisons gt gt lt lt Unary operations abs Binary Operations mod rem amp C C boolean operators always short circuit In Ada there are both short circuiting operations and operations that do not short circuit Short circuiting operations are not considered true operators and as such can t be overloaded see below Membership Tests in and not in are not considered true operators and can t be overloaded if dog in aDogBreed then Put_Line The dog is a breed in the enumerated aDogBreed end if if i in 1
254. er amp ASCII NUL return end if New_Line Write the request GET returns a web page from a web server Also send minimal HTTP header using User Agent Followed with a blank line to indicate end of command meh e OE Toe S Tb tI SGT HALLE Y OTI GOL GL y SendHTTPCommand mySocket GET index html HTTP 1 0 amp ASCII CR amp ASCII LF amp User Agent WebSocket 1 0 BigBookLinuxAda Example amp ASCII CR amp ASCII LF SEASGNUIES CRI amp ASCI LF New_Line read web page back Pine tains Wo Web Rage SainveGie Results SS ShowWebPage mySocket RULE Vaasa SaaS SSS SS Se SS a eee ue close the connection Put Line Closing the connection close mySocket Put Line Demonstration finished have a nice day end websocket Socket Demonstration This program opens a socket to a web server and retrieves the server s home page Initializing a TCP IP socket Socket 2 1 8 Looking for information on www adapower com GetHostByName www adapower com IP number is 4 bytes long Preparing connection destination information file G Linux http www vaxxine com pegasoft people html book 16 html 44 of 47 7 20 2001 11 37 17 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Connect Connect Result 0 222 1 ou Socket 92 Family Address rec F
255. er Luckily Ada provides a package called Address To Access Conversions to convert between C pointers and Ada access types You instantiate the package with the type you want to convert between and the package creates an access type that can be converted to and from an address which is a C pointer The following program demonstrates conversions to and from C pointer types with Ada Text IO System Address To Access Conversions use Ada Text IO procedure pointers is package IntPtrs is new System Address To Access Conversions integer Instantiate a package to convert access types to from addresses This creates an integer access type called Object Pointer five aliased integer 5 Five is aliased because we will be using access types on it int pointer IntPtrs Object Pointer This is an Ada access all type int address System Address This is an address in memory a C pointer begin int pointer five unchecked access Unchecked access needed because five is local to main program file G Linux http www vaxxine com pegasoft people html book 16 html 2 of 47 7 20 2001 11 37 13 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming If it was global we could use access int_address five address Addresses can be found with the address attribute This is the equivalent of a C pointer int pointer IntPtrs To
256. erio controls windows use common os userio controls windows procedure ttdemo is Derine Mindon Controls OKButton aliased ASimpleButton MessageLine aliased AStaticLine The Dialog Record file G Linux http www vaxxine com pegasoft people html book 15 html 2 of 13 7 20 2001 11 36 37 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings DT ADialogTaskRecord begin Start Textlrools StartupCommon demo demo Stabilo otatrupUuserlo Start upCont rols StartupWindows Create a new window The window will not appear until the DoDialog procedure is used OpenWindow To255 Demo Window title at top of window 0 07 78 23 the coordinates ot the window Style gt normal type or window Usually normal HasInfoBar gt true true if control information is displayed at the bottom of the E Wimdow Setup the controls in the window OK Button located near bottom of window Init ORBuUttOH 36 20 44 20 coordinates in window o 4 hot key for OR button SertText OKRButton OK button will have OK setInfo OKButton To255 Select me to quit AddControl SimpleButton OKButton unchecked access IsGlobal gt false Message at top of window in bright red Init MessageLine 1 1 78 1 SetText MessageLine Welcome to TextTools SetStyle MessageLine Bold SetColour M
257. erred defaults There is only one subprogram in this package reset If you are interested in integer operations not covered by the built in Ada features the Interfaces package the package used to interface Ada to other languages defines several bit shifting functions In order to use these functions you ll need to convert or derrive your integer values to one of Interfaces integer types Function Description lRotate Left Rotate bits in integer types leftward lRotate Right Rotate bits in integer types rightward mire E Shift bits in integer types leftward Shift_Right Shift bits in integer types rightward Shift_Right_Arithmetic Arithmetic shift bits in integer types rightward file G Linux http www vaxxine com pegasoft people html book 12 html 31 of 35 7 20 2001 11 34 28 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages C Shift Left is the equivalent of the C lt lt operator Shift Right is the equivalent of the gt gt operator In Gnat bit shifting operations are intrinsic That is they act as built in functions and execute quickly Here is an example of shifting integer values with Ada Text IO Interfaces use Ada Text IO Interfaces procedure shiftMath is six unsigned_64 6 begin put oine Time to do a little bIE Shirceingt New_Line Put_Line Our integer is amp six img P
258. escore to subroutine names so ifyou are importing from g77 you ll need to include the name of the subroutine with a trailing underscore in pragma inport pragma import Fortran MyFortranSubroutine MyFortranSubroutine Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 17 html 11 of 11 7 20 2001 11 37 39 AM Big Online Book of Linux Ada Programming 18 Data Structures 18 Data Structures lt Last Chapter Table of Contents Next Chapter gt Good programmers write good programs Great programmers write good programs and good data structures Organizing your data is as important as the program that crunches the data and produces a result Unfortunately my experiences in the corporate world have taught me that that the only data structure used is the single dimensional array When results are the only goal and more processing power is the cure for bad software design arrays are easy to implement they are built into Ada Even the worst programmer knows how to use an array And arrays are easy to understand Try to use a linked list and a programmer can get into trouble with his boss for using risky advanced technology Alternatively programmers will sometimes rely on the complexity and overhead of databases when a simplier solution using the correct data structure would be faster and easier to implement If you are lucky enough to work for
259. essTif web site at http www lesstif org This site also includes documentation on compiling and installing LessTif There are no Ada bindings for LessTif but there are Ada bindings for Motif which should work equally well for Lesstif The bindings are available from the Home for Brave Ada Programmers http www adahome com Motif and LessTif have not proven to be very popular Motif programs tend to be very large with widgets layouts that are difficult to design and have a heavy reliance on Motif s cumbersome resource files Even small Motif programs typically require contain several hundred lines of source code to set up file G Linux http www vaxxine com pegasoft people html book 15 html 12 of 13 7 20 2001 11 36 38 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings their initial window Toolsets such as Qt used in KDE and GTK used in GNOME have larger followings and Motif support is primarily for older applications being ported to Linux However Motif as a standard is continuing to evolve 15 6 Using the TCL Binding TASH Tcl Ada SHell is a binding to TCL TK It includes both a thin binding to the basic TCL TK functions as found in the C header file tcl h as well as versions of the functions made for easier calling from Ada The binding supports TCL 8 0 http tash calspan com TASH also comes with its own TCL shell interpreter which functions like tclsh but is written in Ada 15 7 Using th
260. essageLine Red AddControl SimpleButton MessageLine unchecked access IsGlobal gt false Display the window and handle any input events When dialog file G Linux http www vaxxine com pegasoft people html book 15 html 3 of 13 7 20 2001 11 36 37 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings is finished return control which completed the dialog loop DoDialog DT exit when DT Control 1 first control is the OK button end loop close the window CloseWindow Shutdown TextTools ShutdownWindows ohutcdownobntrols ShutdownUserIO ShutdownOS ShutdownCommon end ttdemo Package Overview TextTools is broken into 5 main packages based on what they do Common this package contains all the basic data types used by TextTools plus subprograms that work with those types In particular two important types are defined e Str255 most TextTools subprograms use this bounded 255 character string type instead of the standard Ada fixed strings The function To255 converts an Ada string to a Str255 ToString converts in the other direction e Str255List some list controls display a block of text These controls use the Str255List List type a linked list of Str255 strings The subprograms for this type are defined the generic package gen list Most TextTools calls do not return errors There are some exceptions such in the OS package Error numbers are retu
261. ested and ready to be made available use ci or commit Before commiting your changes delete non essential files such as ali o or executable files to save space in the repository The log command gives information about a group of files root redbase cvs cvs log l project evs log Logging project RCS tile usr cvs project currency adb v Working file project currency adb head 1 1 prancha diss d dede Strict access list symbolic names pas T keyword substitution kv total revisions 2 selected revisions 2 description revision 1 1 dates 1999 01 13 174271337 authors kburten state Exp pranches 1 1L file G Linux http www vaxxine com pegasoft people html book 9 html 5 of 6 7 20 2001 11 32 37 AM Big Online Book of Linux Ada Programming 9 Team Development Inicial revision revision loi db dd date 1999 01 13 172273337 author kburtch state Exp lines 0 0 Project started Status gives you an overview of a group of files root redbase cvs cvs status project cvs status Examining project Files currenoy adb Status Up to date Working revision 1 1 1 1 Wed Jan l3 17227233 1999 Repository revision 1 1 1 1 J usr cvs project currency adb v Sticky Tag none Sticky Date none Sticky Options none 9 4 Creating Transcripts with Script So you did something wrong How to you show what you did to your fellow progr
262. et I decided to publish it online so that the facts about Linux Ada programming would be understood This document covers basic software development on Linux a review of the core Ada 95 language and an introduction to designing programs that work with the Linux kernel and standard C libraries It also covers some of the Ada bindings that exist for packages like Motif TCL and GTK This book tries to describe Linux specifics whenever possible This is not another UNIX book recycled with the word Linux substituted in Although many Ada basics are covered this document assumes the reader is familiar with a high level programming language such as BASIC C C Java Borland Delphi programmers will notice similarities between Delphi and Ada Because C is the dominant language in the Linux world the differences between C and Ada are hilighed throughout the text The document is designed to be used as a reference after it s been read with many tables and examples covering common Linux programming problems Although this book covers a lot of material it is not intended as an exhaustive survey of Linux Ada programming Linux is in a constant state of development Refer to your Linux documentation for the latest information and newest features Also Ada 95 has several application specific and portability features which are not covered since they are not related to general Linux Ada programming Because of the fast pace of Linux development
263. ex number at the left hand margin lists the current function The lines above it list the functions that called this function and the lines below it list the functions this one called Maas laine Mies SE index A unique number given to each element of the table Index numbers are sorted numerically Ihe index number is printed next to every function name so it is easier to look up where the function in the table time This is the percentage of the total time that was spent in this function and its children Note that due to different viewpoints functions excluded by options etc these numbers will NOT add up to 100 self This is the total amount of time spent in this function children This is the total amount of time propagated into this tunctqonm by Les children called This is the number of times the function was called If the function called itself recursively the number only includes non recursive calls and is followed by a and the number of recursive calls name The name of the current function The index number is printed after it If the function is a member of a cycle the cycle number is printed between the file G Linux http www vaxxine com pegasoft people html book 6 html 9 of 14 7 20 2001 11 31 54 AM Big Online Book of Linux Ada Programming 6 Development Utilties function s name and the index number For the function s parents the fields have the following meanings self This is t
264. f in out Memory Buffer is begin Buf Read Offset Buf Buffer First Implies a Read offset rewind Buf Write Offset Buf Buffer First Rewind the write offset end Rewind Write end Memory Stream oilid maim sade v I i 2000 11 26 05 00 13 Ww9g Esco c Warren W Gay VE3WWG ve3wwg home com ve3wwg yahoo com Protected under the GNU GPL License with Ada Text IO use Ada Text IO with Memory Stream use Memory Stream This is a demo main program that makes use of our home brewed Memory Buffer Stream To demonstrate a record of type my rec is written to the stream with known values and then is read back twice Then the write offset is rewound float variable F is written back into float variable G into records T and and a new and then read Ur procedure Main is type my_re UAM B Se ie c is record natural integer tras eT alleen Eloot A demonstration record file G Linux http www vaxxine com pegasoft people html book 11 html 33 of 39 7 20 2001 11 33 47 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming end record See Re INE Wis E G begin put line SUE IG bytes mya aerexe Vine Lie Sie re e my rec read Str T put put put put Rewind Read Str my wee read Sir U Rewind _ Writ put_line G Stream_Access my_rec my_rec my_rec float float
265. f 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming E DUPFD constant integer 0 F GETFD constant integer de E SETED constant integer 2 F GETFL constant integer 3 F SETFL constant integer 4 F GETLK constant integer 5 F SETLK constant integer 6 F SETLKW constant integer 7 F SETOWN constant integer 8 F GETOWN constant integer 9 F SETSIG constant integer 10 F GETSIG constant integer 11 function fcntl fd file id operation gt F DUPFD pragma import C fcntl Duplicates a file descriptor same as dup2 but different errors returned New descriptor shares everything except close on exec New descriptor is returned function fcntl fd file id operation gt F GETFD pragma import C fcntl Get close on exec flag low bit is zero file will close on exec kernel call function fcntl fd file id operation F SETFD arg long integer pragma import C fcntl Set the close on exec flag low bit is 1 to make file close on exec kernel call function fcntl fd file id operation F GETFL pragma import C fcntl Get flags used on open kernel call used to open the file function fcntl fd file id operation F SETFL arg long integer pr
266. f the original string Delete remove a string in the midst of the original string file G Linux http www vaxxine com pegasoft people html book 12 html 2 of 35 7 20 2001 11 34 25 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages Count return the number of occurrences of a substring Index locate a string in the original string Index_Non_Blank locate the first non blank character Head return the first character s of a string Tail return the last character s of a string Trim remove leading or trailing spaces duplicate the string a specific number of times Tokenize Translate convert a string to a new set of characters using a mapping function The following program demonstrates many of the standard Ada string subprograms using unbounded strings with Ada Text IO Ada Strings Unbounded Text IO use Ada Text IO Ada Strings Unbounded Ada Strings Unbounded Text IO procedure strdemo is demonstrate some of the Ada strings subprograms teststr string The rich get richer s Unbounded String begin Put_Line This program shows some Ada string capabilities New_Line Pb VObhe test string is Ye Put_Line teststr New_Line Put_Line To_Unbounded_String converts a string to an unbounded string us To_Unbounded_String teststr Put_Line us New_Line P t _Line The length of the String is T amp length us ame P t Lame If we append bu
267. ficial intelligence In 1983 they created the language Ada now known as Ada 83 a heavily modified version of the Pascal language Ada a proper name refers to Countess Ada Lovelace file G Linux http www vaxxine com pegasoft people html book 1 html 1 of 5 7 20 2001 11 28 29 AM Big Online Book of Linux Ada Programming 1 Introduction 1815 1852 considered by some to be the world s first programmer The original Ada had several shortcomings in the areas of software engineering Ada programs tended to be big and awkward to maintain over time In 1990 ANSI began a project to revise Ada to include object oriented features hierarchical program libraries support for other languages and add ons for specialized applications like systems programming real time systems distributed information client server systems and scientific programming The updated language is known as Ada 95 GNAT is a GPL Ada compiler available for Linux Windows NT and many other platforms It was originally created at New York University GNAT is owned by Ada Core Technologies ACT http www gnat com although gnat is free companies who want support can purchase it for a fee The Linux version of GNAT supports the entire Ada 95 standard including all optional features It includes many extensions like cross compiling and support for the C language ACT also provides GLADE a free RPC based TCP IP networking implementation Ada 95 s distributed syste
268. file_id is new integer file ID number are discussed below type mode_t is new integer type gid_t is new integer type uid_t is new integer type size_t is new long_integer function unlink pathname string return integer pragma import C unlink file G Linux http www vaxxine com pegasoft people html book 16 html 11 of 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Delete a file Example Result unlink tmp temp txt amp ASCII NUL function link oldpath newpath string return integer pragma import C link Make a shortcut hard link to a file Example Result link tmp temp txt amp ASCII NUL tmp newtemp txt amp ASCII NUL procedure getcwd bufl out StringPtr buf2 in out stringptr size integer pragma import C getcwd pragma import valued procedure getcwd Return the current working directory function mkdir pathname stringPtr mode mode t return integer pragma import C mkdir Create a new directory and set default permissions function rmdir pathname string return integer pragma import C rmdir Delete a directory Example Result rmdir tmp tempdir amp ASCII NUL function umask mask integer return integer pragma import c umask Sets the default file permissions function stat filename stringPtr buf stat_struct ret
269. fter record is copied This is the last line of the program Finalize Finalized tagged record srpl all Finalize Finalized tagged record sr3 Ada also provides a second tagged record Limited_Controlled which is a controlled record that can t be assigned Consequently it has no adjust procedure 11 5 Multiple Inheritance Like a tree tagged records can only be extended from a single parent Extending from multiple parents is called multiple inheritance and Ada doesn t allow multiple inheritance The Ada designers considered multiple inheritance a feature that adds ambiguity to a language for example if an employee tagged record has two different parents each with a salary field do you merge the salary fields into one or do you have two copies of the field in your record Because there is no consistent solution to this kind of problem the Ada designers decided to not to support multiple inheritance However you can add tagged records as nested fields just like you would a normal record This workaround guarantees that each object will only have one parent it can extend from file G Linux http www vaxxine com pegasoft people html book 11 html 10 of 39 7 20 2001 11 33 45 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming type aClass is tagged record Fl integer end record type anUnrelatedClass is tagged record Ul integer end record type anMIExample is new aClass with UC
270. g checking checking checking checking checking checking creating creating creating dE GNE ROL EOR FOr for FOr FON EON BPOSIXIzZed TSCA m rera aion 45 reo Jo ues LO dlopen in ldl yes Mir PThreads NO Base LinuxThreads yes Linuxthresads w Errorcheck Mutex Sve ssoumclrbgh s mo contig status Makefile Conk ig contig h lt Last Chapter Table of Contents yes file G Linux http www vaxxine com pegasoft people html book 5 html 6 of 6 7 20 2001 11 31 40 AM Next Chapter gt Big Online Book of Linux Ada Programming 6 Development Utilties 6 Development Utilities lt Last Chapter Table of Contents Next Chapter gt 6 1 Saving Time with Gnatstub Starting with gnat 3 11p gnat provides a prototyping tool called Gnatstub Gnatstub takes an Ada package specification and creates a corresponding body ready to have the details outlined in the spec filled in These empty subprograms are sometimes called stubs This is especially useful on a large project where programmers write a series of package specs to test their design Once the package design is set Gnatstub can create a basic body and save the programmers the work of copying and modifying the specification by hand IDE TIA will run gnatstub on the current file using Stub in the File menu For example suppose you have the following package specification in a file called tiny ads package tiny is proce
271. g 15 Free Ada Bindings 15 2 Using Texttools The Texttools packages are a GPL ncurses based library for the Linux console Texttools contain more than 600 procedures and functions to create windows draw scroll bars handle the mouse and keyboard events play sounds and much more The Texttools package also provides a thick binding to Linux kernel calls You can create a wide variety of application programs using Texttools alone This is the same package used to implement TIA to be rewritten KB 15 2 1 Installation 1 In the C code directory type gcc O c c to compile the C files 2 The Ada files should compile when you build your project with Gnatmake If TextTools are installed in a different directory than your project you will need to use the gnatmake I switch When linking you ll need to include the Im and Icurses switches as well as the object files from C code TextTools uses the C math library and ncurses 4 0 For example gnatlink Im Incurses C_code o 15 2 2 Introduction Although there are over 600 procedures and functions in TextTools to open window is fairly uncomplicated Everything in TextTools is drawn in a window Everything in a window is a control sometimes called a widget To display a window you must create a window fill in the window with controls to display and run the window manager s DoDialog command The following program opens a simple window with common os us
272. g Appendix F bcne Ada Numerics Long Complex Elementary Functions e on od ops TODIUNE complex nbrs EET of long float a nlcoty Ada Numerics Long Complex Types eoa cue beni Ada NumericsLong Elementary Function Bm of stdiops for ong floats Ada Numerics Long_Long_ Inst of std ops for long long a nllcef Complex_Elementary_Functions complex nbrs Ada Numerics Long_Long_ Instantiation of long long float a nllcty Complex Types complex nbrs Ada Numerics Long Long Inst of std ops for long long Elementary Functions floats Ada Numerics Short Complex Inst of std ops for short float a nscefu Elementary Functions complex nbrs bonscoty fta Numerics Generic Complex Typs Pie atinan of hont ioa ae nbrs fa nselfu Ada Numerics Short_Elementary_Functions Inst of std ops for short floats a mucor ta Numerics Complex Types i ot oat ceiaple numbers a nudira Ada Numerics Discrete Random PADO ome random m package home Ada Numerics Elementary Function es OL Se opa Tor Moat complex nbrs a nuflra Ada Numerics Float_Random Rd ee a numaux Ada Numerics Aux Internal use a numeri Ada Numerics Defn s of Pi and epsilon a reatim Ada Real_Time Real time timing declarations a retide Ada Real_Time Delays Sleeping using real time types eh Ada generic a sequio Ada Sequential IO TORRES cuc a sfteio Ada Short Float Text IO Inetantiated Text I0 package for short floats a sfwtio Ada Short_Float_Wide_Text_
273. g Extent customers img Put Line The bag total size is amp customerBags Total Size customers img New Line Inserting duplicate customer file G Linux http www vaxxine com pegasoft people html book 18 html 9 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures e 6 9362 ustomerBags Add customers ut_Line Added customer ut_Line The bag is empty ut_Line The bag extent is ut_Line The bag total size is New_Line Iterator example C 7 amp eme Ww amp customer Extent Bag al JE as em vs Ve i Di amp customerContainers Is_ al WF Put_Line Resetting the iterator customerContainers Reset i C customerContainers Current item P taine neci enis ems sesiones che Put Line Are we done Put Line Advancing to the next customerContainers Next i C customerContainers Current item Puc Line ihe current item as customer aid Put_Line Are we done Put_Line Advancing to the next item customerContainers Next i Put_Line Are we done begin C customerContainers Current item exception when BC NOT FOUND gt put line BC NOT FOUND exception end end bag demo Tha The The The The s is a demo of the bag bag bag bag is newly declared is empty TRUE extent is 0 tot
274. g Online Book of Linux Ada Programming 10 An Introduction to Ada Besides Text IO Ada provides additional Text IO packages for the basic Ada data types Using these packages you don t need to use img to convert the variable to a string For example the package Ada Integer Text IO can put and get integers and Ada Float Text IO can put and get floating point numbers You can use these packages simultaneously with Text IO These additional packages do not have Put Line or Get Line because these are specifically for strings The Put command has two additional capabilities to space information to fit into specified field widths and to display numbers in formats other than base 10 with Ada Text IO Ada Integer Text IO use Ada Text IO Ada Integer Text IO procedure basicio4 is this program demonstrates integer input output i integer 5 this variable contains an integer number i initially has the value of 5 begin Put Line This program displays information on the screen Put Line and reads information from the keyboard New Line put rhe value r 1S Put i New Line New_Line Put_Line Type in an integer number Get i New_Line Pu Ow tine value i ist Prater i New Line New_Line Put Line width gt specifies the amount of room to display the number ali ole NC Put_Line This can be used to display columns of numbers put Using a width of 5 tche
275. g arithmetic The position of an enumerated identifer is independent of its assigned value 10 10 Procedures and Functions Ada Statement Description Equivalent procedure A subprogram that returns no value for expressions void f function A subprogram that returns a value for expressions sometype f declare begin A nested block 39 There are several ways to break up an Ada program First a procedure such as the main program is a subprogram which returns no value procedure print_test is begin Text IO Put Line This is a test end print test file G Linux http www vaxxine com pegasoft people html book 10 html 24 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada C a procedure is a void function The second is a function A function is a procedure that can be used in a expressions because it returns a value The value is returned with a return statement function AddOne X integer return integer is begin return X 1 end AddOne AddOne adds one to whatever is in the brackets To add one to a variable called subtotal you d use it like this Total AddOne SubTotal The value in the brackets is the parameter to the function Parameters have modes in out or in out In which is the default if you specify a mode means that the variable is treated as a constant Out means the value is returned when the subprogram
276. g the lists support customized for our container type end customers with ada text io BC customers use ada text io BC customers procedure list demo is customers customerList Single List G aCustomer all customerContainers Iterator class customerList New Iterator customers begin Put Line This is a demo of the Booch components single linked lists file G Linux http www vaxxine com pegasoft people html book 18 html 5 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures New_Line The Newly Declared List Put_Line The list is newly declared Put_Line The list is empty amp customerList Is Null customers img Put_Line The list is shared amp customerList Is_Shared customers img Put_Line The list length is amp customerList Length customers img New_Line Inserting a customer c customerID 7456 c accountBalance 56 74 customerList Insert customers c Put Line Added customer amp c customerID img Put Line The list is empty amp customerList Is Null customers img Put Line The list is shared amp customerList Is Shared customers img Put Line The list length is amp customerList Length customers img C customerList Head customers Put Line The head item is customer id amp c custo
277. g to register the new shared library otherwise Linux will not load it file G Linux http www vaxxine com pegasoft people html book 13 html 13 of 15 7 20 2001 11 35 52 AM Big Online Book of Linux Ada Programming 13 Linux Introduction To load a shared library from the current directory instead of the standard Linux directories use L where period is the current directory Shared libraries have the advantage of making executable s smaller but they are slower to load and execute and use up more memory than static libraries The also have the advantage of being able to be ugraded separately from your program provided you don t change the format of any of the subprograms Too many shared libraries mean that you have small files scattered throughout the lib directories making your program harder to maintain Generally speaking only subprograms that will be shared between programs should be shared libraries and you should combine small related libraries into one shared library For example all the standard C libraries are compiled into one shared library on Linux libc so a from usenet makedll bat gcc c beep adb gnatbind n beep ali gnatlink beep ali o beep jnk mdll W1 base file beep base dlltool dllname beep dll def beep def base file beep base output exp beep exp output lib libbeep a gnatbind n beep ali gnatlink beep ali o beep jnk beep exp mdll W base file beep base dlltool dllname beep dll
278. g trasym IGNAT Traceback Symbolic Symbolic tracebacks is h ECC package Ada C interfacing package Additional C types not oeste Interfaces C Extensions eu VENE i cobal Interfaces COBOL m ee Oe interfacing package li cpoin Interfaces C Pointers IC style pointer arithmetic emp Interfaces CPP pus C class interfacing package li csthre Interfaces C Sthreads Dummy package ican Interfaces C streams he poio ego o a fi cstrin Interfaces C Strings GNAT C string operations i fortra Interfaces Fortran Standard Ada Portat m package i os2err Interfaces OS2Lib Errors OS 2 error codes li os2lib Interfaces OS2Lib OS 2 support i os2syn Interfaces OS2Lib Synchronization los support li os2th Interfaces OS2Lib Threads OS 2 support Packed decimal fixed types i pacdec ___ Interfaces Packed_Decimal support for Machine_Radix 10 computers li vxwork Interfaces Vx Works VxWords API support Dun returning a i addimg System Address Image anm c 64 bit arithmetic with support s arit64 System Arith 64 for intermediate results gt 64 file G Linux http www vaxxine com pegasoft people html book 99_f html 8 of 9 7 20 2001 11 40 56 AM bits Big Online Book of Linux Ada Programming Appendix F s atacco System Address_To_Access_Conversions Conve ane Pa ea on o and access types my bitwise operations s bitops ads System Bit Ops EAR bytes Storage pool with a function s chepoo System Checked
279. ge requires no elaboration and contains no executables For example a package of nothing but type declarations with no default values is pure package money types is pragma pure a simple package nothing to elaborate subtype aCurrency is float type aSalary is new aCurrency file G Linux http www vaxxine com pegasoft people html book 11 html 4 of 39 7 20 2001 11 33 44 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming end money_types Pragma Preelaborate tells Ada that the package requires minimal elaboration You should try pragma pure and if it fails try pragma preelaborate gnat 3 11 introduced the gnat specific pragma No_Elaboration_Code Sometimes this will work when Preelaborate will not Sometimes you can declare a function as pure using pragma Pure_Funciton A pure function is one with no side effects and one that s value doesn t change when executed with the same parameters each time If the only thing standing in your way to using pure or preelaborate are some functions used to assign initial values try declaring them as pure functions If your package or program fails to meet the elaboration restriction requirements the compiler will issue an error 11 2 2 Second line of defense Elaborate Elaborate_Body Elaborate_All Sometimes the hints are not enough For example a package that assigns a value to constant using a function like Sin45 float Ada Numerics Elementary_Func
280. gettime In this case it s not particularly useful to call gettime and throw away the time it gives you In general you should avoid discarding the result because you may find it useful at some time in the future However there are certain C function where the result is provided only for flexibility such as functions that return a pointer in a parameter and return the same pointer as the function result as well These can safely be discarded by treating the function as a procedure If we wanted to export an integer variable called TotalTimeEstimate to C we d use TotalTimeEstimate integer pragma Export C TotalTimeEstimate file G Linux http www vaxxine com pegasoft people html book 16 html 1 of 47 7 20 2001 11 37 13 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming A C function that returns void corresponds to an Ada procedure When importing or exporting to C gnat converts the variable to lower case because C is a case sensitive language TotalTimeEstimate would be called totaltimeestimate in a C program You can override this by providing a specific C name to link to For example pragma Export C TotalTimeEstimate TotalTimeEstimate Import and Export don t require the name be the same at all However using entirely different names in C and Ada will make your program hard to understand If you want to import functions from libraries other than the standard C library
281. gramming 10 An Introduction to Ada this program demonstrates more advanced input output i integer 5 this variable contains an integer number i initially has the value of 5 Ss String l 20 7 this variable contains a 20 character String len natural begin Put_Line This program displays information on the screen Put_Line and reads information from the keyboard Put Line img returns the string representation of a variable s Put Line value The value i is amp i img S CPU set s to 20 periods Put Line The variable s is amp s Put Line Get Line reads a string from the keyboard Put Line Type in a message up to 20 characters and press Enter Get Line s len Put Line After Get Line copies your message to s s is now amp s amp Put Line The message is amp len img amp characters long Put Line The characters after your message remain unchanged end basicio2 This program displays information on the screen and reads information from the keyboard img returns the string representation of a variable s value The value i is 5 Ihe Variable S is lle MEE Get Line reads a string from the keyboard Type in a message up to 20 characters and press Enter jingle bells After Get Line copies your message to s s is now jingle bells The message is 12 characters long The characters after your
282. group gethostid get the unique identifier of the current host gethostnamee get host name getitimer get value of an interval timer getpagesize get system page size getpeername get name of connected peer 4 getpgid get process group getpgrp get process group getpid get process identification 4 getppid get process identification 4 getpriority get set program scheduling priority 4 getresgid get real effective and saved group ID 4 getresuid get real effective and saved user ID de getrlimit get resource limits get trusage get resource limits getsid get session ID pa getsockname get socket name getsockopt get options on sockets gettimeofday get time getuid get user identity gtty unimplemented idle make process 0 idle init module initialize a loadable module entry ioctl control device ioperm set port input output permissions iopl change I O privilege level ipc System V IPC system calls kill send signal to a process killpg send signal to a process group lchown change ownership of a file link make a new name for a file listen listen for connections on a socket llseek reposition read write file offset lock unimplemented lseek reposition read write file offset Istat get file status mkdir create a directory mknod create a directory or spe
283. hanges to the file if any MAP PRIVATE constant aMapFlag 1640214 separate copy for child processes changes kept in memory if any MAP FIXED constant aMapFlag 164104 use specified address MAP ANON constant aMapFlag 164204 just alloc memory no related file MAP ANONYMOUS constant aMapFlag MAP ANON another name for MAP ANON MAP GROWSDOWN constant aMapFlag 16401004 stack line usage MAP DENYWRITE constant aMapFlag 16408004 write lock the file MAP EXECUTABLE constant aMapFlag 16410004 mark as executable MAP LOCKED constant aMapFlag 16420004 don t swap out memory MAP NORESERVE constant aMapFlag 16 4000 don t check for reservations function msync start system address size length flags aMSyncFlag return integer pragma import C msync Updates the file associated with the memory allocated by mmap Returns 1 on an error file G Linux http www vaxxine com pegasoft people html book 16 html 46 of 47 7 20 2001 11 37 18 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming MS_ASYNC 2 constant asyncklag I request memory to be saved soon MS INVALIDATE constant aSyncFlag 2 mark cache as needing updating MS SYNC constant aSyncFlag 4 save memory to file immediately function mlock start system address size long integer return integer pragma import C m
284. hare Generic for compatibility with other Ada compilers Shared_Passive fused for sharing global data with separate RPC partitions Source File Name overrides normal Gnat file naming conventions Source_Reference for use with gnatchop Storage_Size amount of storage space for a task Steam Convert simplified way of creating streams T O subprograms for a given type Subtitle for compatibility with other Ada compilers Suppress tumn off specific checks for common exceptions Suppress_All for compatibility with other Ada compilers Suppress_Initialization disable initialization of variables of a given type Task Dispatching specify how tasks sort dispatches e g FIFO_Within_Priorities TaskInfo specify information about a task Task Storage specifytheguardareaforatask 0 Time Slice specify tasking time slice for main program in Linux Tite for compatibility with other Ada compilers Unchecked_Union treat a record as a C union type Unimplemented_Unit for unfinished units produces a compiler error if they are compiled Unreserve_All_Interrupts allow reassigning of signals normally handled by gnat eg SIGINT Unsuppress opposite of suppress 00000000 Use VADS Size for older Ada code size is equivalent to vads_size Volatile value of variable may change unexpectedly 0 Volatile Components array components may change unexpec
285. he amount of time that was propagated directly from the function into this parent children This is the amount of time that was propagated from the function s children into this parent called This is the number of times this parent called the function the total number of times the function was called Recursive calls to the function are not included in the number after the name This is the name of the parent The parent s index number is printed after it If the parent is a member of a cycle the cycle number is printed between the name and the index number If the parents of the function cannot be determined the word lt spontaneous gt is printed in the name field and all the other fields are blank For the function s children the fields have the following meanings self This is the amount of time that was propagated directly from the child into the function children This is the amount of time that was propagated from the ehsod ts children to tche fPunctuon called This is the number of times the function called this child the total number of times the child was called Recursive calls by the child are not listed in the number after the name This is the name of the child The child s index number is printed after it If the child is a member of a cycle the cycle number is printed between the name and the index number If there are any cycles circles in the call graph there is an entry for t
286. he cycle as a whole This entry shows who called the cycle as parents and the members of the cycle as children The recursive calls entry shows the number of function calls that file G Linux http www vaxxine com pegasoft people html book 6 html 10 of 14 7 20 2001 11 31 54 AM Big Online Book of Linux Ada Programming 6 Development Utilties were internal to the cycle and the calls entry for each member shows for that member how many times it was called from other members of the cycle Index by function name 418 mcount_internal 1 back tectorial S evele 2 3 ada bench2 177 mcount 6 fact elabb 4 cycle gt If factorial is a function internal to program bench2 the function name won t show up in Gprof For example procedure bench2 is function factorial param integer return integer is begin if param gt 1 then return param Tactorial param 1 5 end if return 1 end factorial maxFactorials constant integer 100 type factorialArray is array 1 maxFactorials of integer list factorialArray begin for i in 1 maxFactorials loop list i factorial i end loop end bench2 gprof c bench2 returns the following information Flat profile Each sample counts as 0 01 seconds file G Linux http www vaxxine com pegasoft people html book 6 html 11 of 14 7 20 2001 11 31 54 AM Big Online Book of Linux Ada Programming 6 Development Utilties
287. he data couldn t be read procedure Write fid AFileID data AFileElement write one data item to the file seqio error is raised if the data couldn t be written end SegIO package body SeqIO is pragma optimize space Import C file handling functions type mode t is new integer C mode t type type size t is new integer C size t type subtype ssize t is size t C ssize t type The C file functions we ll be using denoted with a C_ prefix for clarity function C Open return AFileID pragma import C C Open open path string flags integer mode mode t function C Close file AFileID return integer pragma import C C Close close procedure C Read size out ssize t file ARIES data in out AFileElement contes Size E pragma import C C Read read pragma import valued procedure C Read Using an in out parameter is the easiest way to pass the address of the data element Because Ada doesn t allow in out parameters in functions we ll use gnat s valued procedure pragma to pretend read is a procedure procedure C Write size out ssize t file G Linux http www vaxxine com pegasoft people html book 16 html 17 of 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming ie ai dey CB YA SL IVS ep data in
288. he print command gdb printe ch This will print the character in the variable named ch at the time when the program was stopped To look at a core file produced by a segmentation fault use gdb dbase core You can examine the variables at the time the program crashed Gdb contains many other commands You can get online help at any time with the help command GNAT has a hidden gnatdg flag If you compile your program using this flag you ll get extra information for Gdb such as making all temporary variables used by gnat visible to the debugger 8 7 Code Restrictions There are several pragmas for disabling certain language features These restriction pragmas can be used to enforce a certain policy and warn a programmer when the policy is violated For example if you are writing a real time program you may want to disable Ada features that do not have a known response time so that your program will not have random delays The restriction pragmas include file G Linux http www vaxxine com pegasoft people html book 8 html 5 of 6 7 20 2001 11 32 24 AM Big Online Book of Linux Ada Programming 8 Debugging Your Project e Ada_83 do not allow Ada 95 language features e Ada_95 default allow Ada 95 language features e Controlled turn off garbage collection for a type This has no effect with Gnat since it does not implement garbage collection e Ravanscar enforce Ravanscar run time restrictions e Restricted_Run_ Time
289. he source code must be edited to fit the current program The Window Menu opens various grasp windows The Compiler Menu Make builds the project using the make command defined in command setup typically make Compile and Link builds the project using gnatmake Compile compiles the source file without building the project Semantic Check checks the source code for errors Flag Setup configures the switches for compiling linking etc Command Setup configures the commands to compile link etc The Run Menu Run runs the program using popen Run Previous runs the last file that was run Run File runs a particular file Cleanup Session kills any hung processes Doesn t affect daemons The CPG Menu Generate CPG create a Compilexity Profile Graph Weights configure the CPG weights 3 2 5 The Button Bar Auto automatically rebuild the CSD whenever a major change occurs such as inserting a template or loading a new file Generate CSD same as choosing View Generate CSD Font Size changes the font size 3 3 Other Tools and IDEs 3 3 1 VAD Visual Ada Developer VAD is an Ada code generator written in the TCL TK graphics scripting language Besides gnat there are about 10 additional packages you must install before VAD will run You type in a TCL TK description of a VAD widget in a text file and VAD will produce all the necessary source code to use the widget Most graphics formats are supported VAD is available from
290. heck for the end of stream function f function Finish writing any outstanding data to error stream FILES return int Return any error associated with the last stream operation lush stream FIL Es return int the stream RE function fgetc stream FIL Es return int Read one character from the stream Characters will be ASCII values between 0 and 255 and can be converted to a character with character val function fgets SE IG cnar S n int stream FILEs return chars Read a string from the stream Note this is not an Ada string function fileno stream FI LEs return int Return the fine number associated with a stream for use with standard Linux file operations function fopen filename Open a stream function fpure CG aD ste chars Mode chars return FILEs eam FILES return int Write one character to a stream Convert the character to an integer using character val function fputs Strng char Write a string of characters to the stream function f size t read buffer vo S Stream FILEs return int ids size size t count size t stream FILEs return Read count bytes into a buffer of length size and return number of bytes actually read function reopen filename Reopen the stream with a new mode function f seek stream FI chars mode chars stream FILES retu
291. his template will not run by itself If we want to create a CountingTask task we create one by declaring it Taskl Task2 CountingTask Task1 and Task2 are two copies of CountingTask This is equivalent to creating two separate tasks task Taski is entry add amount integer entry currentTotal total out integer end Task2 task Task2 is entry add amount integer entry currentTotal total out integer end Task2 Because task types can be declared we can create 20 tasks at once by declaring an array of 20 CountingTask s CountingTasks array 1 20 of CountingTask file G Linux http www vaxxine com pegasoft people html book 11 html 25 of 39 7 20 2001 11 33 47 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Tasks can also be declared in records as well or allocated dynamically using the new operator type aTaskPtr is access CountingTask ej 8 elileis eke en tp new CountingTask Using new you can create as many copies of a particular task as you need 11 11 4 Protected Items Types Ada tasks are useful for many kinds of multithreading However Ada provides a second method of multithreading called protected objects These are similar to the monitors used by Java In an Ada task you specify when and how different tasks communicate When items are declared protected Ada controls the interaction for you Protected objects are declared the same w
292. hrough all items in the list plus 1 before Is Done is true Because an Iterator is a class wide type it must be assigned a new value when it is declared to avoid a compiler error i charContainers Iterator class charList New Iterator customers 18 1 3 Single linked Lists Creating a single linked list requires the instantiation of 3 separate generic packages BC Containers BC Containers Lists and BC Containers Lists Single To avoid problems with access types these should be declared globally that is in a package spec First a container must be defined to hold the item you want to store in your linked list package Containers is new BC Containers Item Character Second basic operations on lists must be instantiated package Lists is new Containers Lists Finally the single linked list package must be instantiated For an unbounded package you chose a storage pool to use Single linked lists are always unbounded Use Global Heap if you have no preference package LS is new Lists Single Storage Manager gt Global Heap Pool Storage Global Heap Storage The single linked list package provides the following subprograms e Clear destroy the list Insert add an item to the list Append add an item to the end of the list Remove remove an item from the list Purge remove consecutive items file G Linux http www vaxxine com pegasoft people html book 18 html 4 of 26 7 20 2001 11 38 16 AM
293. iables while the program is running The memory is allocated from a region called the default storage pool GNAT sometimes refers to this as the unbounded no reclaim pool because the only limit on the amount of memory you can allocate is the physical limit of the machine and memory is not reclaimed through garbage collection C The default storage pool is effectively the heap Ada uses access types to create a handle to dynamically declared variables type IntegerPtr is access all Integer ip integerPtr new Integer In this example IP access a dynamically declared integer IP is only large enough to hold the address of where the integer is located To access the integer we have to add the suffix all to IP This is called dereferencing lp all 2 55 If you are dereferencing multiple pointers the all is only required at the end to indicate that the final pointer is to be dereferenced for example ptr1 ptr2 ptr3 all The word all in access all is not strictly required If all is included the IntegerPtr type will be compatible on any other integer pointer Without all Ada imposes certain restrictions on what the access type can point to but in general always use access all Memory allocated with new is freed with unchecked allocation see the section on generics You can assign initial values when you create a new dynamic variable In the following example we declare allocate memory and assign an initial value all
294. ibute to round floating point numbers this makes conversion to an integer unnecessary C The fundamental integer types don t wrap around the way C data types do Values that grow too large produce overflow errors However gnat turns off integer overflow exceptions by default to improve performance Ada provides properly behaved C types and conversion functions in the Interfaces C package Interfaces C includes the following types int is new Integer short is new Short Integer tong is mange 2 lba1tSl 12 IbrzESi I Signed char is range SCHAR MIN SCHAR MAX for signed char Size use CHAR BIT type unsigned is mod 2 int Size type unsigned short is mod 2 short Size type unsigned long is mod 2 long Size type unsigned char is mod UCHAR MAX 1 for unsigned char Size use CHAR BIT GNAT has a second package Interfaces C Extensions that includes additional types such as unsigned long long As it s name suggests the Text IO package only performs I O with text not numbers or other types of information If you want to print say and integer value using Text IO you must first convert the integer to a string using the img attribute or image Attributes are discussed in the next section with Ada Text IO use Ada Text IO procedure basicio2 is file G Linux http www vaxxine com pegasoft people html book 10 html 7 of 29 7 20 2001 11 33 05 AM Big Online Book of Linux Ada Pro
295. id set effective user ID setfsgid set group identity used for file system checks setfsuid set user identity used for file system checks setgid set group identity setgroups set list of supplementary group sethostid set the unique identifier of the current host sethostname set host name i setitimer get or set value of an interval timer setpgid set process group ID setpgrp set process group setpriority set program scheduling priority setregid set real group ID setresgid set real effective and saved user setresuid set real effective and saved user setreuid set real and or effective user ID setrlimit set resource limits setsid creates a session and sets the process group ID setsockopt set options on sockets settimeofday get set time setuid set user identity setup setup devices and file systems mount root file not available sgetmask ANSI C signal handling shmat shared memory operations shmctl shared memory control shmdt shared memory operations shmget allocates a shared memory segment shutdown shut down part of a full duplex connection Sligaction change signal action sigblock change blocked signals siggetmask get blocked signals sigmask C macro to create signal masks signal install signal handler sigpause atomically release blocked signals and wait for interrupt Sigpending examin
296. ifreq I O IFMTU const struct ifreq T TOCS LD_SIOCGIFHWADDR struct ifreq I O OCSIFHWADDR const struct ifreq MORE OOGIFENCAP int TIOOSIFENCAP const inc IOCGIFHWADDR struct ifreq I O IOCGIFSLAVE void IOCSIFSLAVE void TOCADDMUTLTI const struct ifreg lt IOCDELMULTI const struct ifreg IOCADDRTOLD void OCDELRTOLD void OCDABP const Struct arprea OCGARP struct arpreq I O OCSARP const Struct arpreq IOCDRARP const struct arpteg IOCGRARP struct arpreq I O file G Linux http www vaxxine com pegasoft people html book 99_e html 9 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E 0x00008962 0x00008970 0x00008971 SIOCSRARP const struct arpregq SIOCGIFMAP struct ifreq I O SLOCSIPMAP const Struct 2freg 4 lt inelude linux soundcard h gt 0x00005100 0x00005101 OsxcUSCSl07 0xC0045103 0x80045104 0x80045105 0x40045106 0x40285107 0x40045108 0x40045109 0x8004510A 0x8004510B 0xC074510C 0x4004510D 0xC004510E 0x4004510F 0xCEBS STO 0x00005111 0x40085112 0xC0045401 0x00005402 0x00005403 0x00005404 0xC0045405 0xC0045406 0x40045407 0x40045408 xCFB85001 0xC0046D00 0xC0046D01 0xCO216D02 0x00005000 0x00005001 0xC0045002 0xC0045003 0xC0045004 0xC0045006 0xC0045007 0x00005008 0xC0045009 zi J Q H L SEQ RESET void CTL SEQ SYNC void L SYNTH INFO struct synth info I O CTL SEQ CTRLRATE int
297. imes be used ffast math gcc will ignore certain ANSI amp IEEE math rules For example it will not check for negative numbers before invoking the sqrt function This improves math performance but can cause side effects for libraries expecting the ANSI IEEE rules to be honoured fomit frame pointer gcc will free the register usually dedicated to hold the stack frame pointer This improves performance but makes debugging difficult many debugging utilities require the frame pointer IDE TIA sets the proper switches for you based on your selections in the project parameters window 7 2 Gnat Source Optimization Options Ada Package Description C C Equivalent ragma Pack Aggregate Use minimum space LU EN the iiid aiid aggregate pragma Optimize Space Time Off How you want your statements di optimized pragma Inline Subprogram Inline the subprogram inline pragma Inline_Always Subprogram o peo a Deke daNonee6 ce ie Don t include ASCII identifiers prag m YP 4 in executable There are six pragmas available to change the size and execution speed of your program Pragma Pack compresses an array record or tagged record so that it uses the minimum space possible For example a packed boolean array takes up one bit for each boolean Pack only packs the aggregate not any aggregate items that might make up the aggregate if you have an array of records you ll need to both pac
298. imitations on certain file systems Use fcntl to lock files instead O_SYNC only works on the ext2 file system or on block devices function creat path string mode mode_t return file_id pragma import c creat Creat is a short form for open path create writeonly truncate mode function close file file id return integer pragma import C close Closes a file function truncate path string length size t return integer pragma import C truncate function ftruncate file file_id length size_t return integer pragma import C ftruncate Shorten a file to a specific length Despite its name ftruncate is a kernel call not a standard C library call like fopen function read file file id b in out buffer length size t return ssize t pragma import C read Read bytes from the specified file into a buffer Buffer is any type of destination for the bytes read with length being the size of the buffer in bytes The number of bytes read is returned or 1 on an error function write file file id b in out buffer length size t return ssize t pragma import C write Write bytes from a buffer into the specified file Buffer is any type of destination for the bytes read with length being the size of the buffer in bytes The number of bytes written is returned or 1 on an error function lseek file file id offset off t whence integer return integer pragma i
299. ine Ada Description C Equivalent Function Command_Name return string The name of this command path argv 0 Function ArgumentCount return natural The number of arguments fargn Function Argument n natural return string The n th argument Jagvin Procedure Set Exit Status e Exit Status The exit status to return exit e Ada interacts with the outside world through the standard Ada package Ada Command Line Suppose you have an Ada program called myprog and a user types in the following command myprog v sally com e myprog is the name of the command e v and sally com are arguments to the command Command Name returns the name of the command If the program was run from a shell it returns the name as typed in by the user In the above example Command Name returns myprog ArgumentCount returns the number of arguments not including the name of the program The shell determines how arguments are grouped together but typically each argument is separated by a space In the above example there are two arguments v and sally Argument returns an argument In the above example argument 1 returns v Set Exit Status gives Ada the error code you want to return when the program is finished running Ada defines two Exit Status values Success and Failure Since Exit Status is just an integer you can return other values Zero indicates that the program r
300. ine HorizontalSep VerticalSep StaticList CheckList RadioList EditList e SourceCodeList used by TIA Windows this is the window manager It creates and draws windows and DoDialog procedure lets a user interact with the window It also handles the Accessories window that appears when ESC is pressed Each package is started with a Startup procedure and shutdown with a Shutdown procedure The only procedure to take parameters is StartupCommon you need to specify a program name and a short name to use for temporary files 15 2 4 Window Overview The Window Manager draws all the windows on the screen For simple programs you will need to use only four Window Manager procedures Open Window this procedure creates a new window Each window has a title coordinates on the screen a style and an optional info bar file G Linux http www vaxxine com pegasoft people html book 15 html 5 of 13 7 20 2001 11 36 37 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings AddControl adds a control to the current window If IsGlobal is false the coordinates you specified in the control s Init call will be treated as relative to the top left corner of the window as opposed to the top left corner of the screen Close Window closes the last window you created DoDialog this procedure displays the window and handles all interaction between the user and the window It has one parameter ADialogTaskRecord whi
301. ing device drivers Normalize Scalars set scalars variables to illegal values whenever possible Optimize indicates how statements should be optimzed Pack indicates that the type should be compressed as much as possible Page fart a new page in a program listing Passive for compatibility with other Ada compilers Polling if on enables exception polling Priority Specify the priority of a task Preelaborate preelaborate the specified package DIEN NUN specify imported ee a that can handle Ada exceptions used with zero cost handling Psect_Object Same as common_object file G Linux http www vaxxine com pegasoft people html book 11 html 36 of 39 7 20 2001 11 33 48 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Pure specifies the package is pure Pure Function specify a function without side effects Queuing Policy How task protected objects are sorted when queued Ravenscar enforce the Ravenscar real time policies Remote Call Interface Ensure a package can be callable by remote procedure calls Remote Types fused for communication between RPC partitions like Ravenscar turns on a number of restrictions for real time programmin Restricted_Run_Time d P MT Restrictions Disable certain language features Reviewable Provide a run time profiling like gpro S
302. int sx00001263 BLARAGET int 0x00000001 FIBMAP int I O 0x00000002 FIGETBSZ int I lt include linux hdreg h gt 0x00000301 HDIO GETGEO struct hd geometry 0x00000302 HDIO GET UNMASKINTR int 0x00000304 HDIO GET MULTCOUNT int 0x00000307 HDIO GET IDENTITY struct hd driveid 0x000005305 HDIO GET KEEPSEITINGS int DseODODUSUS HDIO_ GET CHIPSET ane 0x0000030A HDIO GET NOWERR int 0x0000030B HDIO GET DMA int OxODOOOSTIEK HDIO DRIVE CMD int 7 1 6 0x00000321 HDIO SET MULTCOUNT int file G Linux http www vaxxine com pegasoft people html book 99_e html 5 of 15 7 20 2001 11 40 32 AM Big Online Book of Linux Ada Programming Appendix E 0x00000322 HDIO SET UNMASKINTR int 0x00000323 HDIO SET KEEPSETTINGS int 0x00000324 HDIO SET CHIPSET int 0x00000325 HDIO SET NOWERR int 0x00000326 HDIO SET DMA int lt include linux if_eql h gt 0x000089F0 EQL ENSLAVE struct ifreq MORE I O 0x000089F1 EQL EMANCIPATE struct ifreq MORE I O 0x000089F2 EQL GETSLAVECFG struct ifreq MORE I O 0x000089F3 EQL SETSLAVECFG struct ifreq MORE I O 0x000089F4 EQL GETMASTRCFG struct ifreq MORE I O 0x000089F5 EQL SETMASTRCFG struct ifreq MORE I O include linux if plip h 0x000089F0 SIOCDEVPLIP struct ifreq I O include linux itf ppp h 0x00005490 PPPIOCGFLAGS int Ox00005491 PPPIOCSFLAGS const int 0x00005492 PPPIOCGASYNCMAP int 0x00005493 P
303. ioctlResult Ioctl mixer file id sound mixer read sound mixer volume oldVolume WE master volume now in oldVolume if ioctlResult 1 then Put Line No mixer installed end if newVolume 75 ioctlResult ioctl mixer file id sound mixer write sound mixer volume newVolume master volume is 75 16 17 4 Recording Sound Samples Recording sounds works is the reverse process of playing sounds Open dev dsp for reading and it returns sound data However before you can begin recording from dev dsp you need to describe how you want the recording done You need to select the input source sample format sometimes called as number of bits number of channels mono stereo and the sampling rate speed These are set by using the ioctl function on the dev dsp file To select the input source you ll need to use dev mixer Not finished KB Sound Mixer Recsrc constant integer Sound Mixer Read constant integer Sound Mixer Write constant integer newlInputSource Sound Mixer Mic ioctlResult ioctl mixer file id sound mixer write sound mixer recsrc newInputSource Jm Common formats Audio data formats Note U8 8 and 16 LE 16 for compatibility AFMT QUERY 168000000008 Returns current format AFMT IMA ADPCM 16800000004 ADPCM compressed data AFMT_U8 068000000088 Unsigned bytes
304. ion Stack amp Memory Leak Detection Gnat 3 11 does not display the execution stack in the event of of an exception Gnat 3 12 provides additional information about the source of an exception You can get additional information about the execution stack using the gnat t raceback package 12 15 The gnatmem utility monitors a running programming using the Gnat gdb debugger When the program is finished running gnatmem displays a summary of dynamically allocated memory You can use this information to find memory leaks places in your program where allocated memory was not deallocated Because gnatmem uses gdb the program should be compiled with gdb support turned on the g switch Note gnatmem doesn t work with Gnat 3 11 To run gnatmem type gnatmem program The gnatmem switches are q quiet hides statistics and shows only potential memory leaks n a number between 1 and 10 indicating the depth of the backtrace information o file save the gdb output to the indicated file The gdb script is saved as gnatmem tmp i file processing using the file previously saved with o Use this to test a program that crashed while gnatmem was running 6 5 Conditional Compiling with Gnatprep Although the Ada 95 design team decided against including preprocessing compiler directives like C does gnat provides a preprocessor so you can use conditional compiling directives in your Ada programs Gnatprep the Gnat PREProcessor takes a sou
305. ion errors Hmm Minimal recompilation 00 FM List object file dependences for Makefile a Check objects up to date output next file to compile ifnot Fonam Choose an alternate executable name ja Be quietiterse 00000000000 000000 fs fRecompile if compiler switches have changed lv Display reasons for all re compilations E NO main subprogram zero main GCC command Use this jgnat command GNATBIND command Use this gnatbind command GNATLINK command Use this gnatlink command FAdr Jikecldi alir file G Linux http www vaxxine com pegasoft people html book 19 html 1 of 4 7 20 2001 11 38 32 AM Big Online Book of Linux Ada Programming 19 Specialized Topics aOdir Specify library object files search path Faldr Specify source files search path Hdr LiKe aldir aOdir H Don t look for sources amp library files in the default directory Ldir Look for program libraries also in dir nostdinc Don lookforsources in the system default directory Fnostdib Don t look for library files in the system default directory cargs opts opts are passed to the compiler Fbargsops sfopts are passed to the binder Harsopts opts are passed to the linker Ho Generate debugging information Idir Specify source files search path T Do not look for sou
306. ipes are the equivalent of shell command pipes formed by the l character You can open a pipe to or from a shell command depending if the pipe is for writing or reading respectively These single direction pipe commands are a part of the standard C library function popen command mode string return AStdioFileID pragma import C popen popen Opens a pipe to a Linux shell command Mode can be w for write or r for read procedure pclose result out integer fid AStdioFileID pragma import C pclose pclose pragma import valued procedure pclose Closes a pipe The following program prints to a printer by opening a pipe to the lpr command with Ada Text IO System SeqIO use Ada Text IO procedure printer2 is a program for simple printing gt Pipe Stuff nnmn M file G Linux http www vaxxine com pegasoft people html book 16 html 26 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming type AStdioFileID is a pointer to a Cs function popen comma pragma import C pop opens a pipe to co procedure pclose res pragma import C pcl pragma import valued closes a pipe function fputc c i pragma import C fpu E part of standard C new System Address tandard IO stdio file id nd mode string return AStdioFileID en popen mmand ult out i
307. irectory the hello o and hello ali are information files and can be safely erased However on large project with multiple files leaving them will speed up the building process 4 3 The Three Step Process When you build a project using gnatmake or when you use an IDE to run gnatmake for you gnatmake performs three operations 1 Compiling gnatmake checks your file for errors If there are no errors it creates an object file containing the binary version of your program If there are any errors in your file gnatmake stops 2 Binding gnatmake verifies that all the files in the project are up to date If there are files that need to be compiled gnatmake will compile them as well 3 Linking gnatmake combines all the object files to create an executable program On simple projects these steps can all be done automatically However on some projects with particular requirements you may need to take special actions during one of these steps You can perform these separate steps yourself For example using the hello adb program 1 Compile the program with gcc c hello adb 2 Bind the program with gnatbind hello ali 3 Link the program with gnatlink hello ali Once again you have an executable program called hello file G Linux http www vaxxine com pegasoft people html book 4 html 3 of 8 7 20 2001 11 31 15 AM Big Online Book of Linux Ada Programming 4 From Source Code to Executable 4 4 Gnat Compiling Options Th
308. is known at compile time or there s no heap allocation unbounded using dynamic allocation and item caching or the dynamic a compromize between bounded and unbounded The default if no others are available is unbounded Dynamic and unbounded types can specify a storage manager to use The storage manager is a program that allocates memory Use Global_Heap package if you have no preference Unbounded structures allocate memory whenever a new item is added to the structure Dynamic structures allocate memory in fixed sized chunks Each chunk is large enough for several items The chunk size is set when the dynamic data structure is first created but it can be altered at any time When a chunk is full the structure is grows by the size of another chunk This reduces the number of memory allocations to improve performance Each dynamic structure includes these subprograms e Create Change the chunk size for the collection e Set_Chunk_Size Change the chunk size for the collection file G Linux http www vaxxine com pegasoft people html book 18 html 1 of 26 7 20 2001 11 38 16 AM Big Online Book of Linux Ada Programming 18 Data Structures e Preallocate Increase the size of the collection immediately e Chunk Size Returns the current chunk size The Booch components are organzied in a hierarchy of packages The BC package is the top most package BC defines the basic execptions that can be raised by the various components Con
309. ision Wesley Longman file G Linux http www vaxxine com pegasoft people html book 20 html 6 of 7 7 20 2001 11 38 49 AM Big Online Book of Linux Ada Programming 20 Developing Your Project lt Last Chapter Table of Contents Appendices gt file G Linux http www vaxxine com pegasoft people html book 20 html 7 of 7 7 20 2001 11 38 49 AM Big Online Book of Linux Ada Programming Appendix A lt Chapter 20 Table of Contents Appendix B gt Appendix A The Linux Shell The default Linux shell is bash Here s a summary of common bash shell commands Is lists the files in the current directory root armitage temp ls typescript touch create a new blank file If the file exists changes the time it was last modified but otherwise leaves the file unchanged root armitage temp touch temp txt root armitage temp ls temp txt typescript rm permanently remove a file root armitage temp rm temp txt rm remove temp txt y Note Red Hat defines aliases for rm mv and cp that prompt before they overwrite or erase a file Most other distributions use the default behaviour which is to take action without warning You can disable Red Hat s aliases with the unalias command mv change the name of a file or move it to a new location root armitage temp touch temp txt root armitage temp mv temp txt temp2 txt root armitage temp ls temp2 txt typescript cp copy a fi
310. istmas94 lt Clock then Text IO Put Line It s after Christmas 1994 else Text IO Put Line It s before Christmas 1994 end if Text IO New Line oplit lock d 25 Year Month Day Seconds Text _IO Put_Line TIn 12 5 seconda it will be amp Year img amp amp Month img amp amp Day img Text IO Put Line And amp seconds img amp seconds into the day end caldemo A simple calendar example file G Linux http www vaxxine com pegasoft people html book 12 html 19 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages The current date is 1998 12 17 It s 59775 1850223000 seconds into the day It s after Christmas 1994 In 12 5 seconds it will be 1998 12 17 And 59787 686581000 seconds into the day The GNAT Calendar Time IO package will write a time value according to a format string similar to the Linux strftime function Easter is one of the hardest holidays to calculate The following is a program to calculate the date of Easter Sunday This should be rewritten for Ada Calender KB with Ada Text IO use Ada Text IO procedure easter is procedure findEaster year integer easter month easter day out integer is based on the public domain algorithm by Ed Bernal Quom Cpe Gp ayaa hy ly ocu Zi estais e CIO d begin Gauss famous algorithm I don t know how or why it works
311. ject using the pg switch at both the compiling and linking stages With Gnatmake you must include pg with both cargs and largs switches IDE TIA will profile your project with gprof if you select Profile in the Project menu It automatically rebuilds your project with the necessary gprof switches starts your main program and then displays the gprof results For example we can use Gprof on the following factorial program package fact is function factorial param integer return integer end fact package body fact is function factorial param integer return integer is begin if param 2 then return 1 end if file G Linux http www vaxxine com pegasoft people html book 6 html 5 of 14 7 20 2001 11 31 53 AM Big Online Book of Linux Ada Programming 6 Development Utilties return param factorial param 1 end factorial end fact with fact use fact procedure bench2 is maxFactorials constant integer 1000 type factorialArray is array 1 maxFactorials of integer Pisti I ractorilalArray begin for i in 1 maxFactorials loop laste 3 a ackorial v end loop end bench2 After compiling and linking the program with the pg switch run the program The program produces a gmon out file containing profile information about the program Now we can use Gprof to get an analysis of the program Running gprof c bench2 returns the following information Note that Ada sub
312. k 19 html 2 of 4 7 20 2001 11 38 32 AM Big Online Book of Linux Ada Programming 19 Specialized Topics Fgntp Suppress all checks FgnaP Generate periodic calls to System PolingPoll gnatqq Don t quit try semantics even if parse errors FgnaR List representation information Fgnts Syntax check only Fgnat Tree output file to be generated FgnafTnnn All compiler tables start at nnn times usual starting size gnatu List units for this compilation FgnaU Enable unique tag for error messages gnatv Verbose mode Full error output with source lines to stdout gnatw Warning mode s e l u for suppress error elab undefined FgntW Wide character encoding method h u s e 8 b gnatx Suppressoutputofcross reference information FgnaX Languageextensonspermited Fgnty Enable all style checks Enable selected style checks xxx list of parameters e 1 9 check indentation b check no blanks at end of lines c check comment format e check end labels present f check no form feeds vertical tabs in source Longe h check no horizontal tabs in source i check if then layout k check casing rules for keywords identifiers m check line length lt 79 characters Mnnn check line length lt nnn characters r check RM column layout s check separate subprogram specs present t check token separation rules Fgnat
313. k the array and the records to use the minimum space possible Packing aggregates usually slows down the execution of your program type CustomerProfile is record Preferred boolean PreordersAllowed boolean SalesToDate float end record pragma Pack CustomerProfile file G Linux http www vaxxine com pegasoft people html book 7 html 2 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Programming 7 Optimizing Your Project Gnat can perform close packing that is packing right down to individual bits for array elements or records of 64 bits or smaller Pragma Optimize specifies how you want your statements to be optimized to run as fast as possible time to be as small as possible space or no optimization at all Optimize does not affect data structures pragma Optimize space package body AccountsPayable is Pragma Inline makes Ada inline the subprogram whenever possible That is it physically inserts the subprogram whenever it s named instead of calling it in order the make your program run faster This uses up a lot of space and is only practical for small procedures and functions procedure Increment x integer is begin x x l end Increment pragma Inline Increment Compiling switch O3 must be used or pragma inline is ignored O3 will also automatically inline short subprograms for you Pragma Inline_Always forces inlining between packages like gnatn regardless of whethe
314. l record In complex classes there will be times when you ll want to define a record that you never intend to assign variables to For example anEmployeeProfile doesn t contain enough fields to completely describe any employee only the tagged records file G Linux http www vaxxine com pegasoft people html book 11 html 6 of 39 7 20 2001 11 33 44 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming derived from anEmployeeProfile are usable When particular record exists only to be extended it called an abstract record You declare abstract records with the keyword abstract type anEmployeeProfile is abstract tagged record name string 1 80 doge cm ger end record If you try to create anEmployeeProfile record Ada will report an error since you said that this record can only be extended into other records Ada requires that subprograms that work with tagged records be declared immediately after the type declaration Each procedure or function can only take one tagged record as a parameter C Methods are normal subprograms with an object being referred to as a parameter myobj method x would be method myobj x or method x myobj in Ada type aSalaryEmployee is new anEmployeeProfile with record salaryRate float end record procedure SetSalaryRate s in out aSalaryEmployee class rate float is begin S salaryRate rate end SetSalaryRate function GetSalaryR
315. lans to fold Gnat into the Gcc project for Gcc 3 1 and have moved some of their discussions to the gcc mailing list 2 1 Installing the ALT RPMs The Ada Linux Team version of Gnat is available from their web site Versions exist for the Red Hat S u S E and Debian distributions They may also work on the Mandrake and Caldera distributions The ALT versions include support for ASIS GLADE and native Linux threads The package includes gnatgcc a version of gcc with Gnat and C support and gnatgdb a version of gdb that supports Ada source code plus gnatprep and the other Gnat utilities file G Linux http www vaxxine com pegasoft people html book 2 html 1 of 4 7 20 2001 11 30 05 AM Big Online Book of Linux Ada Programming 2 Installing Gnat on Linux The rpm files are built for Red Hat and S u S E distributions If you try installing it on another distribution use nodep to ignore any package dependency warnings 1 Download and read the readme file ps Download the gnat 3 xxp runtime rpm file where xx is the current version of Gnat and is the rest of the filename For older RPMs this is gnat 3 xxp 3 Download the gnat 3 xxp rpm file For older RPMs this is gnat 3 xxp devel 4 rpm i gnat 3 xxp runtime 5 rpm i gnat 3 xxp 6 Download and install any of the additional Gnat packages you need The rpm files on the ALT site are configured to work with the ALT version of gnat To install them simply download
316. ld link Parent follows the parent link Each of these subprograms can be used as a procedure to move the root of the tree or as a function to examine the item the link connects to item Item At tree Pie essendi o ES emm item Item At Left Child tree Bibie heo c SETS ME Cm F When the root of the tree is moved any items above the new root that aren t referenced anymore are destroyed To move around the tree without destroying nodes which is typically what you want to do create an alias to the root of the tree with Create prior to moving root Left eee tr I Create a refrercnce to the Toot _Child tree safe old root is not destroyed Moving into an empty null position in the tree is allowed but any attempt to look at the item there will raise an exception The leaves and the parent of the root are empty The Trees Binary package provides the following subprograms Clear Destroy the tree Insert Insert an item at the tree s root Append Add an item in the place of a particular item moving the old item to a new position Remove Remove an item from the tree Share Create an alias to a subtree of the tree Child Left Child Right Child Move to a child item Parent Move towards the root Set Item Make an item the root of the tree Has Children True if the tree has any children items Is Null True if the tree has no items Is Shared True if any
317. le G Linux http www vaxxine com pegasoft people html book 2 html 3 of 4 7 20 2001 11 30 05 AM Big Online Book of Linux Ada Programming 2 Installing Gnat on Linux compile a second gcc compiler just for use with Gnat For gnat 3 13 you ll need the gcc 2 8 1 source code You should be able to compile an older version of gcc to work with newer C libraries provided the compiler is only a few months out of date Now follow the directions to compile Gnat Make sure libgnat a is accessible to the linker If it isn t copy it to usr lib and run ldconfig to update Linux s shared library tables More here KB 2 4 Case Study Installing Gnat 3 11 on over an old Linux Distribution We installed Gnat 3 11p on a Pentium running a Slackware distribution with egcs and lib6 We wanted to replace egcs with gcc 2 8 1 and install the Gnat binaries compiled for 2 8 1 over top We first went to the Sunsite mirror which provides Linux compiled binaries of gcc ready to be unpacked and installed Unfortunately the readme file reported they had trouble compiling gcc and supplied egcs instead egcs is based on gcc 2 8 0 which meant that we couldn t use it with gnat 3 11 Instead we downloaded the gcc 2 8 1 source code from a GNU FTP mirror site and prepared to build the compiler from scratch 1 We ran Gnat doconfig program and select option 1 The gcc path that it s expecting is displayed as i686 pc linux gnu This was going to be our configuration hos
318. le root armitage templ t cp temp2 txt temp3 txt root armitage temp ls temp2 txt temp3 txt typescript grep search a file for a word or phrase file G Linux http www vaxxine com pegasoft people html book 99 html 1 of 3 7 20 2001 11 39 10 AM Big Online Book of Linux Ada Programming Appendix A root armitage temp grep procedure home ken ada basicio2 adb procedure basicio2 is find search for a file root armitage temp find home ken type f name basicio3 adb home ken ada basicio3 adb Ipr print a file root armitage temp lpr basicio3 adb Iprm stop printing a file if the file hasn t started printing yet root armitage temp lprm dfA017Aa01370 dequeued cfA017Aa01370 dequeued Ipq list your files waiting to be printed root armitage temp lpg no entries cat display a file root armitage temp cat hello adb with Ada Text_I0O use Ada Text IO procedure hello is begin put lane Hello worl ys end hello less display a file one screen at a time allowing you to move around root armitage temp less basicio adb er translate characters to translate a DOS text file to a Linux text file use file G Linux http www vaxxine com pegasoft people html book 99 html 2 of 3 7 20 2001 11 39 10 AM Big Online Book of Linux Ada Programming Appendix A be dg e lt dos text gt linux txt lt Chapter 20 Table of Contents Appendix B gt file
319. le is a directory IsFile true if file is a regular file MakeTempFileName creates a random file name for a temporary file Erase deletes a file LoadList load a Str255List list from a file SaveList save a Str255List list to a file MyID return the PID for your program SessionLog write to the session log If a SYS directory exists SessionLog creates a file called session log in that directory All SessionLog calls write to this file 15 2 10 UserlO Overview The UserIO package handles all the input and output for TextTools Unless you are writing a game or new controls you ll probably won t need to use UserIO at all However there are a few useful subprograms to be aware of Beep play a wav file Requires Warren Gay s wavplay program These files must be saved in the SYS directory with the name of the beep sound in upper case file G Linux http www vaxxine com pegasoft people html book 15 html 9 of 13 7 20 2001 11 36 38 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings e Keypress get a keypress e DrawErr draw an error message DrawErr draws the text on the left side screen in white Use only for emergencies e GetDisplayInfo retrieve information about the current screen such as whether it supports colour and it s dimensions Use this information to resize your windows for different screens Example Beep Startup play startup sound Keyboard Macros UserIO will load a
320. le with a version number eg 1 1 1 2 with each revision and maintains a change log CVS an extension to RCS is described below Once you initialize RCS for a project people in your project check out with the co command a copy of a file and when they re done making changes they check in the file with the ci command RCS is also a good tool for maintaining documentation Read the rcsintro man page for more information on getting started The following is a transcript of a session using RCS Assume that you have a source file called f c To add the source file to RCS you d use ci You are prompted for a general description of the file and RCS assigns version number 1 1 to the file The file is deleted from your directory and moved into RCS s care armitage home ken ada rcs ci f c BCS f c v lt F E enter description terminated with single or end of file NOTE This is NOT the log message gt gt Curreny Definitions gt gt initial revision 1 1 done armitage home ken ada rcs ls RES To check out the file read only use co The file reappears armitage home ken ada rcst co f c RCS f Cry E revision 1 1 done armitage home ken ada rcs ls RCS fC To check out a file to change it use co I lock out others armitage home ken ada rcst co 1 f c RCS f e V gt f C revision 1 1 locked done Suppose you add the line test line to the file Resdiff will report any changes you v
321. led keywords These are words that have special meaning to Ada Second the words that aren t in bold are identifiers These are the names of variables procedures packages and other items with names or titles in the language IDE Ada IDE s will hilight keywords in bold for you Some editors such as emacs elvis and nedit will also hilight keywords This is a good way to check for spelling mistakes In this program begin is a keyword because Ada uses the word begin to denote where the program is to begin file G Linux http www vaxxine com pegasoft people html book 10 html 1 of 29 7 20 2001 11 33 05 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada executing instructions On the other hand firstProgram is an identifier because it is the name of our program All keywords in Ada are also reserved words this means that the keywords cannot be used as identifiers The main program can have any name as long as the name matches the filename In gnat the source code for a main program ends in adb Ada body This program should be saved as firstprogram adb C The main program doesn t have to be main unless you save the program as main adb If you call a program test adb remember that test is a built in shell command To run a program named test you ll have to type test instead of test to avoid running the shell command by mistake Comments are denoted by two minus signs This
322. lengtch img k YW characters long E end ScanString begin Put_Line This program demonstrates the features of the Put Line IO Aux package This package adds three functions Put_Line to simple Text_IO programs New_Line Put_Line File Exists tests for a file s existence if File Exists TestFile then Put Line TestFile amp exists else Put Line TestFile amp doesn t exist end if New Line Put Line Get Line is the same as Ada Text IO s Get Line Put Line except that reads a string of unlimited length P t _Line Tand doesn t return an explicit length value J New_Line E Put_Line Please type in a string of any length ScanString GNAT IO Aux Get Line file G Linux http www vaxxine com pegasoft people html book 12 html 7 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages New_Line Put nae Tne third Function is a version of Get Linen Pu ut_Line that reads any string Irom a Text_IO files New_Line end ioaux This program demonstrates the features of the T IO Aux package This package adds three functions to simple Text IO programs File Exists tests for a file s existenc etc passwd exists Get Line is the same as Ada Text IO s Get Line except that reads a string of unlimited length and doesn t return an expli
323. les quotactl manipulate disk quotas read read from a file descriptor readdir read directory entry readlink read value of a symbolic link readv read a vector reboot reboot or enable disable Ctrl Alt Del recv receive a message from a socket recvfrom receive a message from a socket recvmsg receive a message from a socket rename change the name or location of a file rmdir delete a directory Sbrk change data segment size sched get priority max get static priority range sched get priority man get Static priority range E sched getparam get scheduling parameters sched setscheduler get schedule algorithm parameters sched rr get interval get the SCHED RR interval for the named process E sched setparam set scheduling parameters 4 sched setscheduler set schedule algorithm parameters file G Linux http www vaxxine com pegasoft people html book 99_c html 3 of 5 7 20 2001 11 39 50 AM Big Online Book of Linux Ada Programming Appendix C sched yield yield the processor select synchronous I O multiplexing semctl semaphore control operations semget get a semaphore set identifier semop semaphore operations send send a message from a socket sendfile transfer data between file descriptors sendmsg send a message from a socket sendto send a message from a socket setdomainname set domain name setegid set effective group ID i seteu
324. ling speed end if Now read dev dsp for the raw sound data If you want to save the sound as an au file you ll have to create the au header information to attach to the sound data file G Linux http www vaxxine com pegasoft people html book 16 html 36 of 47 7 20 2001 11 37 16 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming 16 18 Audio CDs 16 19 Kernel Pipes 16 20 Shared Memory Shared Memory Flags IPC_CREAT Create new shared memory block IPC_EXCL plus read write and execute bits IPC_PRIVATE indicates no key is supplied function shmget key key_t bytes integer shmflag integer return integer pragma import C shmget Key is an id you supply to identify the memory or IPC_PRIVATE for no key bytes is the minimum amount of memory that you need shmflag indicates options for this call Returns 1 on error or an id for the memory Example shmid shmget mykey 4096 IPC_CREAT IPC_EXCL 8 0660 function shmat result out system address shmid integer shmaddr system address shmflag integer return system address pragma import C shmat Shared memory attach Makes shared memory accessible by returning a pointer to it shmid is the id returned by shmget if shmaddr isn t zero the kernel will the address you give instead of chosing one itself shmflags are additional options Returns the address of the shared memory or an address of 1 for an error Ex
325. lls Florist is designed for gnat and runs on Linux as well as Solaris OFS1 AIX IRIX and HP UNIX Florist works closely with the gnat run time system you must compile Florist against a particular gnat installation If you change your gnat installation you will need to recompile Florist Older versions of Florist for Gnat 3 11 work best with a version of Gnat compiled for FSU threads Native threads require some patching to work and not all Florist features are supported see the Florist documentation for details For more information on FSU threads read the multitasking section above Newer versions of Florist such as the ALT RPM works with the normal native threads version of Gnat Commercial support for Florist is available form ACT Because the Linux kernel largely adheres to the POSIX standard many of Florist functions have the same parameters as their Linux counterparts Florist divides the POSIX functions into a set of 73 Ada packages all prefixed with the name posix The main package is called posix ads and contains the definition of data types and many of the basic POSIX functions To write Florist applications you ll need to link in the Florist library with Iposix check and if necessary use I to indicate where you ve installed the package specifications file G Linux http www vaxxine com pegasoft people html book 15 html 1 of 13 7 20 2001 11 36 37 AM Big Online Book of Linux Ada Programmin
326. lock Deny page swapping on this block of memory allocated by mmap Only a superuser process may lock pages Returns 1 on an error function munlock start system address size long_integer return integer pragma import C munlock Allow page swapping on this block of memory allocated by mmap Returns 1 on an error function mlockall flags aLockFlag return integer pragma import C mlockall Deny swapping on all memory for this process Only a superuser process can lock memory Returns 1 on an error function munlockall return integer pragma import C mlockall Allow swapping on all memory for this process Returns 1 on an error MCL CURRENT constant alockrilag 1 lock current blocks MCE FUTURE constant aLockFlag 2 lock subsequent blocks function brk end_data_segment system address return integer pragma import C brk Resize the Intel data segment to the specified ending address Returns 1 on an error procedure sbrk increment long integer pragma import C sbrk Increase the Intel data segment by the specified number of bytes 16 25 Exit Procedures procedure C exit pragma import C C exit exit pragma import valued procedure C exit exit is aC a standard C library function that closes all your standard C library files and stops your program This procedure is meant to be used by C It is not recommended in an Ada program
327. lowing are the predefined Ada 95 pragmas Abort_Defer defer abouts over a block of statements Ada 83 enforce Ada 83 conventions even if compiler switches say otherwise Ada 95 enforce Ada 95 conventions even if compiler switches say otherwise AL Calls Remote AII subprograms in a RPC package spec are RPC callable Annotate add information for external tools Assert ereate an assertion Asynchronous feall to remote subprogram can complete before subprogram is done Atomic identifier must be read written without interruption Attach Handler installa signal handler procedure C Pass By Copy when calling C functions use pass by copy not by reference when able Comment same as Ident Common Object for Fortran create variables that share storage space Complex Representation use gcc s complex numberformat forspeed t Component Alignment indicate how record components should be stored Controlled turn off garbage collection for a type no effect in gna Convention apply a convention to an identifier CPP_Class treat a record or tagged record as a C class CPP_Constructor treat imported function as a C classconstructor CPP_Destructor treat imported function as a C class destructor 0 CPP Virtual import a C virtual function 0 CPP_Vtable specify a virtual func
328. lue Model Modulus Output Partition_ID for distributed processing Pos position in a discrete type such as an enumerated opposite of val Position Pred previous value in a discrete type Range range of values for a type Read Remainder Round Rounding Safe_First Safe_Last Scale file G Linux http www vaxxine com pegasoft people html book 10 html 13 of 29 7 20 2001 11 33 06 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada Scaling Signed_Zeros Size size of storage in bytes Small Stoarge_Pool used to set the storage pool for a pointer Storage_Size Succ next value in a discrete type Tag tag for a tagged record Terminated true if task has terminated Truncation Unbiased_Rounding Unchecked_Access return access type but ignore scope checks Val value of a discrete type at a certain position opposite of pos Valid determine if the expression evaluates to a legal result Value convert string to a value opposite of image Version Wide_Image same as image but for a 16 bit string Wide Value same as value but for a 16 bit string Wide_Width Write Here s a list of additional gnat specific attributes should fold these in above Abort_Signal task abort exception Address_Size number of bits in an address Bit offset to first bit in object Default_Bit_Order whether or not CPU uses high order first Elab_Body the procedure that elaborates a package body Elab_S
329. m Stream_Access is Mem_Str Memory Buffer Stream Ptr Memory Buffer Stream Ptr Stream begin Rewind Read Mem Str Mem Buf end Rewind Read procedure Rewind Write Stream Stream Access is Mem Str Memory Buffer Stream Ptr Memory Buffer Stream Ptr Stream begin Rewind Write Mem Str Mem Buf end Rewind Write file G Linux http www vaxxine com pegasoft people html book 11 html 31 of 39 7 20 2001 11 33 47 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming procedure Free Stream Stream_Access is type Memory_Buffer_Stream_Ptr is access all Memory_Buffer_Stream procedure Free Stream is new Ada Unchecked Deallocation Memory Buffer Stream Memory Buffer Stream Ptr Str BEER Memory_Buffer_Stream Ptr Memory_Buffer_Stream_Ptr Stream begin eS a desc em osse Pe 12 6 end Free procedure Initialize Buf in out Memory Buffer is begin Buf Read_Offset Buf Buffer First Buf Write Offset Buf Buffer First end Initialize procedure Write Buf in out Memory Buffer Item Stream Element Array is Commies peream Element Or BSc tem Wasted Ss Ib mi ETSI Last Stream Element Offset Buf Write Offset Count 1 begin if Last
330. m relies upon and automatically compiles any packages that need compiling For example gnatmake main adb will compile the file main adb automatically compiling all Ada files referenced by main adb if necessary This is unlike other building tools like make and cook because the dependancy of source files is listed in every Ada file by the with statement make and cook are designed to work with C which has no equivalent statement and requires the programmer to list the dependencies in a separate file When gnatmake is finished compiling it will automatically bind and link the program producing an executable file called main There are times when you want gnatmake to compile the project but not to bind or link it You can tell gnatmake not to link by using the n option gnatmake n main adb Here is a summary of the gnatmake switches e a consider all files even read only source files and standard system files like ada text 1o e c compile only e f recompile entire project file G Linux http www vaxxine com pegasoft people html book 4 html 7 of 8 7 20 2001 11 31 15 AM Big Online Book of Linux Ada Programming 4 From Source Code to Executable jn on multiprocessor machiens compile using n processes at once k ignore errors and compile as much as possible M create a list of dependences suitable for make s Makefile i instead of the current directory keep intermediate files in directories where their sources a
331. m Address easier to read than System Address type aHostEnt is record h name System Address pointer to offical name of host h aliases System Address pointer to alias list h_addrtype int 0 host address type PF INET h length NETUS 0 length of address h addr list addrListPtr pointer to list IP addresses we only want first one end record defined in man gethostbyname package HEptrs is new System Address To Access Conversions aHostEnt Again we need to work with C pointers here subtype aHEptr is System Address and this is easier to read use HEptrs use makes equals visible function getHostByName cname string return aHEptr pragma import C getHostByName look up a host by it s name returning the IP number function htons s unsigned short return unsigned short pragma import C htons acronym host to network short on Intel x86 platforms switches the byte order on a short integer to the network Most Significant Byte first standard of the Internet procedure memcpy dest src System Address numbytes int pragma import C memcpy Copies bytes from one C pointer to another We could probably use unchecked conversion but the C examples use this errno S abide pragma import C errno last e
332. master volume setting SOUND_MIXER BASS Is Bass setting SOUND_MIXER_TREBLE 2 Treble setting SOUND_MIXER_SYNTH B FM synthesizer volume SOUND_MIXER PCM 4 dev dsp volume SOUND_MIXER_SPEAKER 5 internal speaker volume if attached to sound card SOUND MIXER LINE 6 line in jack volume SOUND_MIXER_MIC p microphone jack volume SOUND_MIXER_CD B CD input volume ISOUND MIXER IMX p Recording monitor volume SOUND MIXER ALTPCM I0 volume of alternate codec on some cards SOUND MIXER RECLEV 11 Recording level volume SOUND_MIXER_IGAIN 2 mptgan SOUND_MIXER_OGAIN I3 Output gain SOUND MIXER LINE i4 Input source 1 aux SOUND_MIXER_LINE2 i5 Input source 2 aux2 SOUND_MIXER_LINE3 16 Input source 3 line Reading or writing values have a special bit set Ken check using soundcard h Ioctl calls return an integer value Volume levels can be 0 to 100 but many sound cards do not offer 100 levels of volume dev mixer will set the volume to setting nearest to your requested volume Not complete KB file G Linux http www vaxxine com pegasoft people html book 16 html 34 of 47 7 20 2001 11 37 16 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Sound_mixer_volume constant integer 0 Sound_Mixer_Read constant integer Sound Mixer Write constant integer oldVolume integer
333. mation to gnat accordingly You can specify additional gnatmake options like n for no main program in Ada when you want to call Ada subprograms from another language linking options such as Linux libraries you need to link to and the name of the main program Static binding turns static binding on and off CPU Options 486 Pentium Pentium II Other Optimize Options None Basic Size Speed Debugging Options e Prelease assert debug pragma s on basic and elaboration checks on e Alpha Beta assert debug pragma s on basic checks on no elaboration checks e Release assert debug pragma s off all non essential checks off Project Type e Program compile and link project as an executable program e Package compile but don t link project since there s no main program e Static Library unfinished compile and generate a static library file named lib lt project gt a e Shared Library unfinished compile and link a shared library file named lib lt project gt so a Builder Specify the name of the program to build the project with usually gnatmake e Gnatmake Gnat s project builder e Make Linux s standard project builder e Cook an enhanced project builder based on make Static Linking select this to link in all the libraries used into a self contained executable Egcs select this to run egcs instead of gcc untested ALT select this to compile on a system using the ALT version of gnat Build TIA attempts to build
334. may want to make libgnat a shared library e you may want to upgrade gnat for the newest C libraries e you may want to change the multithreading model In order to recompile Gnat you ll need the following 1 A copy of the gcc sources in order to build a copy of gcc that s compatible with Gnat The required version is listed in the Gnat documentation 2 A copy of the gnat sources The sources are available for download from the gnat download site and its mirrors I should compile gnat and make notes and flush out the details more KB First you need to recompile the gcc compiler Make sure you follow gcc s instructions for activating Ada support make CFLAGS g fsigned char LANGUAGES c c ada make stagel make CC stagel xgcc Bstagel CC g O2 fsigned char STAGE PREFIX stagel1 LANGUAGES c c ada sbuild tools and lib with CC xqece B There are two problems that can arise 1 The standard C library may have changed 2 The souce code for the gcc compiler itself may have changed Changes to the C library rare unless the library is several generations out of date Even so by consulting the man pages you can usually find out the new parameters the various C functions expect Upgrading gcc to a new version of gcc however can be difficult Gnat s gcc patches are designed for a specific version of gcc It is usually a good idea to get a copy of the source code for the version of gcc Gnat was designed for and fi
335. merID img C customerList Foot customers Put Line The foot item is customer id amp c customerID img New Line Apending a customer e c stomerID 93962 c accountBalance 88 92 customerList Append customers c Put Line Appended customer amp c customerID img Put Line The list length is amp customerList Length customers img C customerList Head customers Put Line The head item is customer id amp c customerID img C customerList Foot customers Put Line The foot item is customer id amp c customerID img New Line Iterator example Put_Line Resetting the iterator customerContainers Reset i C i customer ontainers Current_item 33 5 Put Line The current item is customer id amp c customerID img Put Line Are we done amp customerContainers Is Done i img Put Line Advancing to the next item customerContainers Next i e customer ontainers Current ltem a Put_Line The current item is customer id amp c customerID img Put_Line Are we done amp customerContainers Is Done i img file G Linux http www vaxxine com pegasoft people html book 18 html 6 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures Put_Line Advancing to the next item customerCon
336. missions of a file chown change ownership of a file chroot change root directory __clone create a child process for multithreading close close a file descriptor connect initiate a connection on a socket creat open and possibly create a file or device create module create a loadable module entry delete module delete a loadable module entry dup duplicate a file descriptor dup2 duplicate a file descriptor execve execute program exit cause normal program termination fchdir change working directory fchmod change permissions of a file fchown change ownership of a file fcntl manipulate file descriptor fdatasyne synchronize a file s in core data with that on disk flock apply or remove an advisory lock on an open file fork create a child process fstat get file status fstatfs get file system statistics file G Linux http www vaxxine com pegasoft people html book 99_c html 1 of 5 7 20 2001 11 39 50 AM Big Online Book of Linux Ada Programming Appendix C fsync synchronize a file s complete in core state with that on disk ftruncate truncate a file to a specified length get kernel syms retrieve exported kernel and module symbols getdents get directory entries getdomainname get domain name getdtablesize get descriptor table size 4 getgid get group identity geteuid get user identity getgid get group identity getgroups get set list of supplementary
337. mming tools unlike older Ada compilation systems Fun Fact When Gnat 3 11p was released Robert Dewar said that Linux would never be a billion dollar platform and deserved no special consideration by ACT By the time Gnat 3 12p was released just over a year later the Red Hat company was worth more than 18 billion dollars or 4096 of the server market The first platform supported by Gnat 3 12p was Linux 1 3 Why Use Ada C and C represent the de facto standard for Linux programming After all the kernel itself is written in C However C is not suitable for all kinds of projects because different computer languages have different strengths and weaknesses Ada was designed for team development and embedded systems leading to advantages over C in development time and debugging An in depth 1995 study by Stephen F Zeigler http www adaic com docs reports cada cada art html showed that development in Ada costs about half that of C It also suggests that Ada produces almost 90 fewer bugs for the final file G Linux http www vaxxine com pegasoft people html book 1 html 2 of 5 7 20 2001 11 28 29 AM Big Online Book of Linux Ada Programming 1 Introduction customer GNAT was developed closely with gcc the native C compiler for Linux Unlike some compilers that translate a program into C and then feed the C program into gcc gcc has built in support for the Ada language Like g the GNU C compiler gnat works with gc
338. mp s amp ASCII NUL Put Line Queuing Y amp s amp if Result 0 then Put Line system call for lpr failed else Put Line Printing is queued end if end PrintFile procedure CreateFile s string is run the touch command Result integer begin P t tTine Creaking es amp t es Result System touch amp s amp ASCII NUL if Result 0 then Put Line system call for touch failed else file G Linux http www vaxxine com pegasoft people html book 13 html 3 of 15 7 20 2001 11 35 51 AM Big Online Book of Linux Ada Programming 13 Linux Introduction Put_Line Spool file initialized end if end CreateFile the text file to print SpoolPath constant string tmp spool txt SpoolFile File Type begin To open an out file in text io it must exist Create file will create a new spool file Set Output will redirect all output to the gt spool file CreateFile SpoolPath Open SpoolFile out file SpoolPath Set Output SpoolFile write the report to printer Linux normally will not eject a page when printing is done so we ll use New Page Put Line Sales Report Een ci ME Lt DET New Line Put Line Sales were good New Page Now restore output to the screen close the file and quete the file for printing satiate 1pr
339. mport C lseek Move to a particular position in the specified file Whence is a code representing where your starting position is Offset is how many bytes to move There are three possible whence values SEEK SET constant integer 0 from start of file SHREK CUR Constant Integer s l offset from Current position SEEK END constant integer 2 from end of file File input output is naturally suited to generic packages You can use the generic package to hide the low level details of the standard C library In following example SeqIO is a generic package for reading and writing a sequential file of some type using the kernel calls mentioned above ze i A simple sequential IO package using standard C functions file G Linux http www vaxxine com pegasoft people html book 16 html 16 of 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming generic type AFileElement is private package SeqIO is type AFileID is new short integer Seqio error exception function Open path string read boolean true return AFileID open a new file for read or write procedure Close fid AFileID close a file procedure Read fid AFileID data in out AFileElement read one data item from the file seqio error is raised if t
340. ms annex The GNAT manual describes their compiler as an industrial quality Ada 95 compiler integrated into the GCC retargetable compiler system GNAT is a complete compiler validated on several platforms that includes support for all the Ada 95 annexes specified in the Ada Reference manual Because of its integration into the GCC system GNAT is available on a large number of hardware operating system platforms and can be used as a cross compiler from any of its targets to any other one Because of the common code generator technology of GCC GNAT has excellent support for multi language programming Ada C C Fortran etc GNAT also represents a substantial improvement in Ada compilation technology It s sic open system philosophy stands in contrast with the opaque approach of older Ada compilers There are no hidden and complex central libraries whose use requires a totally new set of commands and no rigid development environments that often force needless recompilations While preserving all of Ada s safety GNAT s source based model provides the flexibility and efficiency typically encountered in C development environments Furthermore GNAT s flexibility greatly facilitates its integration within third party development environments and CASE tools A number of standard editors debuggers profilers memory analyzers test coverage or configuration management tools etc can be used with GNAT which coexists comfortably with familiar progra
341. n D y P t hine The C string 3 i3 VU g Tol Adal sprallig Wu Ww Free sp end ctest This is an example of Interfaces C The C string so is This as a string 17 3 Interfaces C Pointers Package One C feature that Ada programs lack is pointer arithmetic In C you can move pointers forward and backwards through an array by using simple arithmetic operations For example adding two to an character pointer move the pointer two characters forward in a string Decrementing an integer pointer moves the pointer back one index position in an integer array Since pointer arithmetic is important in many C programs especially sorts Ada 95 provides a standard generic package called Interfaces C Pointers which implements access types that can use pointer arithmetic To instantiate the package you need to specify the elements that will be in your arrays an unbounded array that will contain the elements the range of index values and a default terminator value used by some of the package s subprograms For example to create C style pointers for the unbounded Char_Array C string type in Interfaces C you could instantiate the package with file G Linux http www vaxxine com pegasoft people html book 17 html 2 of 11 7 20 2001 11 37 38 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada package StringPtrs is new Interfaces C Pointers Index gt size_t the index range is size t Element
342. n readdir info DirInfoCPtr return DirEntCPtr pragma import C readdir function rewinddir info DirInfoCPtr return integer pragma import C rewinddir function telldir info DirInfoCPtr return integer pragma import C telldir function seekdir info DirInfoCPtr position integer return integer pragma import C seekdir scandir hard to use from Ada So strermneg e SiO esop CSteingrPrers Ob 7ecr Pointer Result integer IDs S MID Se TERES OG ESI direntop DirentPtrs ObJect_ Pointer Position integer LastPosition integer begin Put_Line This program demonstrates Linux s directory functions New_Line getcwd example getcwd s s length Put The current path simplified is Put Line Head s Index s ASCII NUL amp 1 Index for fixed strings takes a string as the second parameter We ll make a string containing an ASCII NUL with amp get current dir name example csop To Pointer get current dir name file G Linux http www vaxxine com pegasoft people html book 16 html 23 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Pile TIrhe c rrent ED dil S Put Line Head csop alll Index csop all ASCIT NUL amp T1 mkdir example create a directory named temp Result mkdir temp am
343. n to cover those features that have been the most use to me over the years in my projects For example array slicing alone could take up several pages of discussion but I ve never had a need for it in recent years Of course you may be involved in a project in which array slicing is crutial In these cases I recommend you get a good Ada 95 reference such as Barnes Programming in Ada 95 Likewise this is not a complete introduction to computer programming Some background knowledge is assumed Ada also has many specialized features for specific tasks such as scientific computing and real time systems Where I deliberately skip a subject I usually make a note that I have done so I ve also hilighted useful information for C programmers who are learning Ada Now on to main programs 10 1 Your Main Program A main program in Ada is a procedure with no parameters that starts your program running This is the set of instructions that the computer begins to follow when your program is first executed The following program will print a message on the screen when you run it with Ada Text IO procedure firstProgram is my first Ada program begin Ada Text IO Put Line This is my first Ada program end firstProgram C Ada is not case sensitive WITH or With is the same as with An Ada program consists of sets of words and punctuation symbols The words fall into two categories First the words in bold in bold are cal
344. name as a pointer to a C string Unlike getcwd symbolic links aren t dereferenced Use this function to show the current directory to a user procedure chdir path string pragma import C chdir Change the current working directory to the specified path Example chdir home bob stuff amp ASCII NUL function mkdir path string mode size_t return integer pragma import C mkdir Create a new directory with permission bits as specified by mode function rmdir path string return integer pragma import C rmdir Remove a directory function opendir path string return System Address pragma import C opendir Open a directory in order to read its contents with readdir function closedir info System Address return integer pragma import C closedir Close a directory openned with opendir Info is the C pointer returned by opendir function readdir info System Address return DirEntCPtr pragma import C readdir Read the next entry in the directory A null C pointer is returned if there is no more entries Info is the C pointer returned by opendir function rewinddir info System Address return integer pragma import C rewinddir Begin reading from the top of the directory Info is the C pointer returned by opendir function telldir info System Address return integer pragma import C telldir Mark the current position in the directory to return
345. natG show pseudo code of how Gnat interprets your source code gnatic use character set c gnatkn constrain file names to n characters gnatl include source code with error messages gnatL C exception handling set jmp long jmp gnatmn show no more than n errors gnatn allow inline subprograms across source code in different files gnatN inline as much as possible even subprograms not marked for inlining gnato turn on checks normally turned off such as numeric overflow checking gnatp turn all checks off gnatq don t quit because of errors compile entire source file gnatr check for reference manual source code layout gnatR listing with alignment info file G Linux http www vaxxine com pegasoft people html book 4 html 4 of 8 7 20 2001 11 31 15 AM Big Online Book of Linux Ada Programming 4 From Source Code to Executable e gnats synatx check only e gnatt create tree output file e gnatu list units being compiled e gnatwm warning mode s m These include O gnatwa show all optional warnings gnatwA show no optional warnings gnatwc warnings for always true false expressions in statements gnatwe treat warnings as errors gnatws suppress warnings gnatwl warnings on elaboration errors Oo C8 O OC 96 gnatwu warnings on unused variables uninitialized parameters unused packages o gnatyk check indentifier case gnatx suppress cross reference information g
346. naty Impose line length limit etc KB gnatzm generate distribution stubs for m gnatZ zero cost exceptions default gnat83 enforce old Ada 83 conventions gnat95 enforce Ada 95 conventions default mno 486 create an executable that can run on a Intel 386 or newer m486 create an executable that can run on a Intel 486 or newer mcpu model compile an executable for the given cpu model fstack check check for stack overflows The gnat switches can be combined together such as gnatbcs for gnatb gnatc and gnats Many of the GCC switches listed in 4 5 can be used as well 4 4 1 Run time Error Checking Ada has extensive checking for run time errors By default gnat turns off some of these checks to improve the speed of the programs To turn on all error checking you need to use gnato gnatE switches To turn off all error checking you need to use gnatp IDE TIA sets these switches for you based on your choices in the project parameters window 4 4 2 Checking without Compiling In gnat 3 10 if you want to check a source file without actually compiling it use the gnatf utility In gnat 3 11 or later you can use gcc with the gnatc option to check a source file IDE TIA uses gnatc when you chose File Check file G Linux http www vaxxine com pegasoft people html book 4 html 5 of 8 7 20 2001 11 31 15 AM Big Online Book of Linux Ada Programming 4 From Source Code to Executable 4
347. nd procedure Adjust is used after an object is assigned in an assignment statement file G Linux http www vaxxine com pegasoft people html book 11 html 8 of 39 7 20 2001 11 33 45 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Adjust is very smart Temporary storage is used for self assignment If Adjust fails because of an exception Finalize is not executed C Adjust is like a C copy constructor except that Ada will copy the object before calling Adjust With a copy constructor you must copy the object yourself in the body of the constructor Unlike a copy constructor Adjust only executes during assignment with text_io sample use text_io sample procedure controlledtest is srpl srp2 SampleRecPtr sr3 SampleRec begin Put Line This is the first line of the program New Line Put Line This is an example of controlled tagged records New Line Put Line Executing srpl new SampleRec srpl new SampleRec New Line Put Line Executing srp2 srpl copying a pointer Srp2 srpl New_Line PUG line Executing ss t sepl all copying a record pointed to sr9 srepl ari New_Line Put_Line This is the last line of the program end controlledtest with ada finalization use ada finalization package sample is type SampleRec is new Controlled with null record type SampleRecPtr is access all SampleRec
348. nder Proj For simple single file programs put the name of the program in the main line and select your CPU type TIA will save this information when you quit in a adp file Ada Project You can check the current file with Check If there are errors use Err to move to the place where an error occurred and the error message will appear on the bottom of the screen Repeatedly use Err to fix all errors Note that as you edit the program such as adding or deleting lines Err may not take you to the exact line because the lines have moved Build your project with Build and you re ready to run your program 3 1 2 TIA Keyboard Legend These are the key functions in TIA If you are running TIA under X Windows the X window manager may use some of these key combinations for its own purposes Control Keys Control 6 Mark Unmark Control A Execute macro follow with the key for the macro Control B Copy single line or to the mark Control E End Control L Redraw screen Control N Page Down Control P Page Up Control T Backtab back one item on screen Control V Paste Control X Cut single line or to the mark Control Y Home Navigating The TIA Screen End last line of text Home first line of text Page Up Up One Page Page Down Down One Page Esc F1 TextTools Accessories Menu Tab Next Item On Screen Backtab Previous Item On Screen note Linux console doesn t support the back tab key use control t
349. ne Put_Line Exception_Information provides the name message and any traceback intormat ion yy Put Line Exception Information occurrence New Line Put Line The Gnat Current Exception package contains short hand Put Line versions of Exception Name Exception Message Exception Information Put_Line These functions assume you re referring to the current exception Put Line Gnat Current Exception Exception Name is amp Exception Name Put Line Gnat Current Exception Exception Message is amp Exception Message amp file G Linux http www vaxxine com pegasoft people html book 12 html 33 of 35 7 20 2001 11 34 28 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages us New Line Put Line The Gnat Traceback Symbolic package returns the contents of the Put Line runtime stack That is it shows which subprograms were being Put Line executed when the exception occurred Put Line The symbolic traceback is Put Line Symbolic Traceback occurrence New Line Put Line Ada Exceptions can also save and re raise in progress exceptions New Line Put Line Save Occurence can save the in progress exception Save Occurrence saved exception occurrence Put Line Exception now saved New Line Put Line Reraise Occurrence will raise an in progress exception Put Line Reraising the one w
350. ne com pegasoft people html book 11 html 13 of 39 7 20 2001 11 33 45 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming What do you do when something unexpected error occurs Unexpected errors are called exceptions in Ada For example running out of memory is an exception Ada has a number of predefined exceptions and examples of when they occur e CONSTRAINT ERROR number out of range like assigning 1 to a positive variable e NUMERIC ERROR dividing by zero e SELECT ERROR caused by task select statement with no else part STORAGE ERROR running out of memory TASKING ERROR failure of a task to handle an entry call PROGRAM ERROR hitting the end of a function without returning anything ASSERT ERROR a pragma assert failed You can turn off checking for most of these errors using pragmas but they are usually a sign that something if fundamentally wrong with your program Gnat provides a compiler option to turn these checks off for the release version of a program The standard libraries have additional exceptions defined To handle an exception you need an exception part at the end of a subprogram When the exception is raised occurs execution immediately jumps down to the exception part The exception part contains a list of exceptions to check for plus an others part similar to a case statement procedure exceptional Total out integer is begin do Some stuff exception when constraint
351. ne numbers Although you could represent a database table using a sequential IO file it would be very difficult to use To look up the 1000th entry in the file you would have to read through the first 999 entries The Ada equivalent to a database table is called a direct IO file Some languages refer to this kind of file as a random access file A direct IO file is called direct because you can move directly to any row in the file without having to read any other rows The rows in a direct IO file are typically represented by records athough they can be any data of a known length and the columns are the fields in the records Direct IO files can also use variant records Ada will ensure there is enough space in each entry for the largest variation You can open an existing direct IO file or you can create a new one When you open or create a file you have to indicate what file mode you ll be using In mode files can only be read Out mode files can only be rewritten Unlike sequential IO files there is also an In Out mode which allows you to both read and write records This is the most common mode for accessing direct IO files If you move to a position beyond the end of the file such as trying to write to row 100 when there are only 50 rows the other unused rows will be created and filled with zero bytes ASCII NUL in characters or strings 0 in integers and long integers and so forth The only way to shorten a direct IO file is
352. ned with the type statement type aSalary isnew float type aSmallSalary isnew Salary range 0 0 35_000 0 file G Linux http www vaxxine com pegasoft people html book 10 html 18 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada When you create a new type the type is considered to be incompatible with the type it is derived from If you want to add a small salary to a salary you ll have to use type casting even though they are both floats tomalsalary Bugqsalary Tasa lary eysineulbdl Seule c8 asme Misallar y7 totalSalary bigSalary aSalary smallSalary To type cast one type into another use the type name and the value to convert in parantheses after it C type value style of type casting doesn t work in Ada C Ada has stronger restrictions on typecasting In C for example you can cast a character pointer as an integer pointer Although this is considered a bad programming practice it is allowed Ada will not allow this kind of type casting Use subtype to create a type aSmallSalary that is compatible with aSalary subtype aSmallSalary is aSalary range 0 35 000 0 Subtype can also be used to rename types subtype sb is aSalaryBonusForEmployeesNamedBobStevens In this example sb is a short form for aSalaryBonusForEmployeesNamedBobStevens sb is techncially called a subtype mark a term which sometimes appears in Gnat error messages One
353. ners contents Bignell up type of fruit Pears file G Linux http www vaxxine com pegasoft people html book 18 html 22 of 26 7 20 2001 11 38 18 AM Plums Other JE Big Online Book of Linux Ada Programming 18 Data Structures end record function sortCriteria left right aShipment return boolean for sorting the AVL tree package shipmentContainers is new BC Containers item aShipment pasic fruit container package shipmentTrees is new shipmentContainers Trees basic tree support package shipmentAVLTrees is new shipmentTrees AVL Somit enam eni Storage Manager Global Heap Pool Storage gt Global Heap Storage on AVI c SPON end fruit avl package body fruit avl is function sortCriteria left right aShipment return boolean is begin return left number right number end sortCriteria end fruit avl AVL trees have slower inserts and deletes than binary trees but are faster than a normal binary tree for searching 18 1 15 Multiway Trees A multiway tree is a tree with any number of unsorted children as opposed to a binary tree which always has no more than two chidren The subprograms are similar to a binary tree The append procedures add child items to an item A new function called Arity returns the number children an item has Multiway trees should not be Guarded 18 1 16 Graphs Essentially graphs are a gener
354. new shipmentContainers Trees basic tree support package shipmentBinaryTrees is new shipmentTrees Binary Storage_Manager gt Global_Heap Pool Storage gt Global_Heap Storage our binary tree support procedure inOrdershipmentTraversal is new shipmentBinaryTrees In Order visitShipment an in order traversal procedure preOrdershipmentTraversal is new shipmentBinaryTrees Pre Order visitShipment a pre order traversal procedure postOrdershipmentTraversal is new shipmentBinaryTrees Post Order visitShipment a post order traversal end shipment binary with ada text io use ada text io package body shipment binary is file G Linux http www vaxxine com pegasoft people html book 18 html 19 of 26 7 20 2001 11 38 18 AM Big Online Book of Linux Ada Programming 18 Data Structures procedure visitShipment s aShipment OK our tree traversal function begin Put Shipment or Put s number img EXE as IPG C s guan licy img PUC USI GOR We jie Put_Line s contents img OK true end visitShipment end shipment_binary with ada text_io use ada text_io procedure bintree_demo is use shipmentBinaryTrees TOOR Binary_Tree 5 Binary Tree S aShipment OK boolean begin Put Line This is a demo of the New Line hubs ls the root ltem s number 5 s quantity S Contents ce Cherrien
355. ng are related utility functions added by ACT They are not standard UNIX functions like the above function file exists name chars return int Returns O if a file doesn t exist 1 if it does function is regular file handle int return int Return 1 if given handle is for a regular file or 0 for some other kind of file procedure set binary mode handle int Read text without translation Only works if compiled with text translation required procedure set text mode handle int Translate text Only works if compiled with text translation required procedure full name nam chars buffer chars Return the full path of a file as a C string The following program demonstrates some of the c stream functions with text io unchecked deallocation Interfaces C Streams use text io Interfaces C Streams procedure cstreamtest is EA k ETLES line2write constant string This is a test cline2write constant string This is a test amp ASCII NUL path constant string testfile xxx cpath constant string path amp ASCII NUL fileMode constant string w amountWritten size t result i Inte begin Put_Line This is an example of Interfaces C_Streams New_Line fd fopen cpath address fileMode address if ferror fd 0 then Put Line Opened amp path amp with fopen Put Line W
356. ng term storage They cannot be used to create disk files although the data could be saved to disk and reloaded later 18 1 1 Containers file G Linux http www vaxxine com pegasoft people html book 18 html 3 of 26 7 20 2001 11 38 16 AM Big Online Book of Linux Ada Programming 18 Data Structures Containers form the cornerstone of the Booch components Containers are a controlled tagged record that encloses an item The Booch components are composed of items stored in containers that are arranged in different ways To use any of the Booch components a container must be instantiated to hold your item For example to create a new package to manage character in containers use package charContainers is new BC Containers Item gt Character 18 1 2 Iterators The Container package also manages the iterators used by the Booch components An iterator is a variable that keeps track of the position in a data structure during a traversal Iterators are created by New Iterator in a data structure s package but the subprograms that work with the iterator are defined in the Container package e Reset start a new traversal at the first item e Next continue to another item in the component e Is Done True if there are no more items e Current Item return the current item The Is Done function indicates when all items have been traversed When Is Done is true Current Item is undefined In other words the program must loop t
357. ng to a fixed string Unbounded strings are strings that can be of any size They are typically implemented by dynamic allocation which makes them slow but they don t waste memory the way bounded strings do and there s no risk over a string overflow The standard Ada library Ada Strings Unbounded contains the definition of unbounded strings and operations on them including a function to convert an unbounded string to a fixed string C Unbounded strings are not exactly the same as C strings For one thing unbounded strings don t end in null characters C String support is in the packages Interfaces C with Ada Text IO Ada Strings Unbounded Text IO use Ada Text IO Ada Strings Unbounded Ada Strings Unbounded Text IO procedure unbio is file G Linux http www vaxxine com pegasoft people html book 12 html 1 of 35 7 20 2001 11 34 25 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages this program demonstrates basic input output with unbounded strings These routines are mor ise eR ORIS S because they avoid conversion into standard Ada E SIE IS TAGIS us Unbounded String begin Put_Line This program displays information on the screen Put_Line and reads information from the keyboard New_Line puc rine voces a stringu us Get_Line New_Line Put_Line Put_Line displays a line of text and advances to Put_Line the next line Put The string
358. no time accumulated S cumulativeselfselftotal time seconds seconds callsTs callTs callname 0 000 000 00990 000 00main 0 000 000 0010 2 000 SUD ada penchz etc Note gnatmem doesn t work with Gnat 3 11 6 7 Shared Libraries Using GnatDLL To be written KB 6 8 Source as Web Pages Using GnatHTML This utility converts an Ada source file into a series of indexed coloured HTML web pages By default the web pages are stored under a subdirectory called HTML By posting your source code on a network or the Internet developers can examine your work with a web browser The gnathtml switches are e 83 look for Ada 83 keywords only e cc color comment colour d convert files which depend on this file as well D like d but also convert standard library files f crossreference local entries In display line numbers every n lines Idir file search path odir specify the output directory default html pfile use this Gnat project file sc color symbol colour e T ile read the files to convert from this file Example using gnathtml with the following program with Ada Text IO use Ada Text IO file G Linux http www vaxxine com pegasoft people html book 6 html 12 of 14 7 20 2001 11 31 54 AM Big Online Book of Linux Ada Programming 6 Development Utilties procedure htmltest is a demonstration of gnathtml function factorial n natural return natural is compute rhe factorial of n
359. not finished 16 22 Semaphores not finished 16 23 Sockets 16 24 Memory Management 16 25 Exit Procedures 17 Moving C Programs To Ada 17 1 c2ada Translating Your Programs 17 2 Interfaces C package 17 3 Interfaces C Pointers package 17 4 Interfaces C_Streams package 17 5 Ada and C Files 17 6 A Word on Interfaces Fortran 18 Data Structures 18 1 Using the Booch Components 18 1 1 Containers 18 1 2 Iterators 18 1 3 Single linked Lists 18 1 4 Double linked Lists 18 1 5 Bags file G Linux http www vaxxine com pegasoft people html book book html 8 of 10 7 20 2001 11 22 56 AM The Big Book of Linux Ada Programming 18 1 6 Sets 18 1 7 Collections 18 1 8 Queues 18 1 9 Stacks 18 1 10 Deques 18 1 11 Rings 18 1 12 Maps 18 1 13 Binary Trees 18 1 14 AVL Trees 18 1 15 Multiway Trees 18 1 16 Graphs 18 1 17 Smart Pointers 18 1 18 Booch Multithreading 19 Specialized Topics 19 1 Ada Meets Java 19 1 1 The Java Virtual Machine unfinished 19 1 2 JGNAT unfinished 19 2 ASIS unfinished 20 Developing Your Project 20 1 The Project Proposal 20 2 The Design Phase 20 3 The Development Phase 20 4 The Alpha Beta Release 20 5 Releasing Your Software 20 5 1 A Third Party Library 20 6 Distribution Formats 20 6 1 RPM Red Hat Package Manager not finished 20 6 2 TGZ Packages 20 6 3 TAR BZ2 Packages 20 6 4 Other Formats 20 7 Man Pages 20 8 Linux Software Map Entry 20 9 Licensing Options
360. nt The results assume that you started the program by typing cmdtest v with text_io Ada Command_Line Environment use text_io Ada Command_Line Ada Command_Line Environment procedure cmdtest is begin Put_Line This is an example of Ada Command_Line New_Line Put Line The command to invoke this example was amp Command Name amp Put Line There is are amp Argument Count img amp command line arguments My if Argument Count gt 0 then Put Line The first argument is amp Argument 1 amp end if New Line file G Linux http www vaxxine com pegasoft people html book 14 html 11 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming Put_Line There is are amp Environment_Count img amp environment variables Put_Line The first environment variable as amp Environment Value ls GC Yee Set SINN Stacus Success end cmdtest This is an example of Ada Command_Line The command to invoke this example was cmdtest There is are 1 command line arguments The first argument is v There is are 2L euh ronment variables The first environment variable is LESSOPEN lesspipe sh s Environment variables can be removed using the Gnat Ada Command Line Remove package 14 6 GNAT Directory Operations Package This Gnat package allows you to create and explore directories Although the p
361. nteger fid AStdioFileID ose pclose procedure pclose nteger fid AStdioFileID return integer te fpute library Writes one charctera to a function fputs s s tring fid AStdioFileID return pragma import C fpu part of standard e cS aS JB prany sente ever el She resliale Ero CT usate Tin PipeID AStdioFileID procedure BeginPrinti 7 File TD for lpr pipe ng is open a pipe to lpr begin Put Line Opening pipe to lpr PipeID popen lpr amp ASCII NUL w amp ASCII NUL end BeginPrinting procedure EndPrinting is close the pipe R Linux normally w printing us done Result integer begin Result touc ch pclose Result Pip end EndPrinting esult doesn t matter ill not eject a page when so we ll use a form feed aracter pos ASCII FF PipeID emu T Input OureuE SCU procedure Print s print a string return and line Result integer begin Result fputs s end Print begin string S o the pipe with a carriage feed C ASCER CR ec ASCII LE E ASCA NUE Open the pipe to the lpr command Put Line Starting to print BeginPrinting Print Sales Report Print file integer PipeID Jie Print
362. ntime stack That is it shows which subprograms were being xecuted when th xception occurred The symbolic traceback is 0x8049cb3 in exc at exc adb 10 Ada Exceptions can also save and re raise in progress exceptions Save_Occurence can save the in progress exception Exception now saved Reraise_Occurrence will raise an in progress exception Reraising the one we just saved raised EXC E call exec development team Call stack traceback locations 0x80497eb Because the reraised exception propogated all the way to the main program and caused it to fail the final line was actually written to Standard Error Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 12 html 35 of 35 7 20 2001 11 34 28 AM Big Online Book of Linux Ada Programming 13 Linux Introduction 13 Linux Introduction lt Last Chapter Table of Contents Next Chapter gt This section is an introduction to Linux programming 13 1 Introduction to Processes Linux is an operating system It controls the execution of programs and access to system resources Linux can run multiple programs at one Each running program is referred to as a process The operating system switches to a new process every 100 milliseconds by default like everything else in Linux this value can be customized by changing the kernel source code Even on a Linux computer with only one
363. nux Ada Programming Appendix F lt Appendix E Table of Contents Glossary gt Appendix F Overview of GNAT Packages This is an overview of some of the more useful packages included with Gnat 3 13p s more than 300 standard packages F ile Package Description a astaco Ada Asynchronous_Task_Control Unimplemented a caldel Ada Calendar Delays Sleeping using Calendar types a acalend Ada Calendar Standard Ada Caledar package a chahan Ada Characters Handling pas Deu dm handling package a chlat1 Ada Characters Latin_1 Standard Latin 1 Character set definition a coliea Ada Command Line Environment standard Ada environment ee a colire Ada Command Line Remove Unset environment variables a comlin Ada Command_Line Standard Ada command per package powita Ada Characters Wide Lain 1 ess S NEA character set Ee msladiDrcn Limits and def ns for Decimal m a adiocs Ada Direct IO C Streams pu ZAE reading writing C direct files ade aaa aO Standard Ada generic direct I O package a dynpri Ada Dynamic Priorities Changing task prionies ynp on the fly ding Ada exception a except Ada Exceptions EE a exctr Ada Exceptions Traceback PUP ber for ece piicn tracebacks blico da Finalization List Controller p for controlled tagece records file G Linux http www vaxxine com pegasoft people html book 99_f html 1 of 9 7 20 2001 11 40 56 AM Big Online Book of Linux Ada Programming Appendix F
364. nux Programming Lock File var lock customers txt Wait gt 5 0 Retries gt 10 Files are unlocked using Unlock_File This procedure deletes the lock file Unlock ha le ShockDir ee eus omes sui P Unlock File var lock customers txt The lock file approach is a voluntary convention Programs that honour the convention can share the file in an orderly way A program that doesn t use the package will not be denied access For true file locking use the Linux kernel calls described in 16 7 Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 14 html 15 of 15 7 20 2001 11 36 20 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings 15 Free Ada Bindings lt Last Chapter Table of Contents Next Chapter gt 15 1 Using Florist the POSIX binding Florist Florida Statue University Forest is a GPL binding of the POSIX IEEE Standard 1003 5b 1996 standard operating system functions These include file operations date and time functions and multitasking the same kinds of function provided by the standard C libraries and the Linux kernel If you are writing an application that will run on several different operating systems Florist provides a level of operating system independence Once you install gnat and Florist on your new platform you should be able to recompile a Florist application without having to worry about variations in system ca
365. nux include linux socket h Make this a new integer for strong typing purposes type aNetProtocol is new int IPPROTO TCP constant aNetProtocol 6 The number of the TCP IP protocol IEP protocol defined as 6 in etico cols See man 5 protocols Make this a new integer for strong typing purposes file G Linux http www vaxxine com pegasoft people html book 16 html 39 of 47 7 20 2001 11 37 17 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming type aNetDomain is new integer PF_INET constant aNetDomain 2 The number of the Internet domain Make this a new integer for strong typing purposes type alInAddr is record addr unsigned 0 end record for alnAddr size use 96 A sockaddr in record is defined as 16 bytes long or 96 bits Request Ada to use 16 bytes to represent this record type aSocketAddr is record family aProtocolFamily AF INET protocol AF INET for TCP IP port unsigned short 0 the port number eg 80 for web ip alinaddr IP number end record an Internet socket address defined in usr src linux include linux socket h and usr src linuz include linuxz in function socket domain aNetDomain Suc aSocketType protocol aNetProtocol return aSocketFD pragma import C socket initialize a communication socket i abit error
366. oat end record just a typical record type salesptr normal is access all sales record This is a normal access type It is allocated in the default storage pool aka the heap The default storage pool is called Unbounded No Reclaimed Pool That is there s no size limit and memory is not reclaimed by garbage collection A debug pool sales debug pool System Debug Pools Debug Pool declare a new debug pool Debug Pool is a GNAT specific pool type salesptr debug is access all Sales Recorg for salesptr debug storage pool use Sales Debug Pool This access type has no garbage collection but raises exceptions on allocation or deallocation errors useful for tracking down storage leaks All 4 possible exceptions are file G Linux http www vaxxine com pegasoft people html book 11 html 17 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming shown in this program procedure Free is new Unchecked_Deallocation sales_record salesptr_debug procedure to deallocate salesptr debug access types Sr aliased Sales Recorg spd spd2 spd3 salesptr debug begin Put Line Fun with debug storage pools New Line Debug Pool Exception 1 begin Put Line Accessing a non allocated access type is an exception Put Line spd salesman
367. of this dependency your programs should be compiled against a specific Linux distribution Don t assume that if a Red Hat disk and a Slackware disk are published in the same month that they are using exactly the same versions of the C library By the same token don t assume you can simply include libc 6 0 y with your program and update the user s version of libc by installing yours overtop This can cause many programs to crash if they can t find the particular version of libc that they need The same is true of the gnat library libgnat a ACT does not guarantee that a program compiled for gnat 3 11 s gnat library will run with gnat 3 12 s gnat library In fact it probably won t 13 11 Linux Basics To be filled in KB Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 13 html 15 of 15 7 20 2001 11 35 52 AM Big Online Book of Linux Ada Programming 14 Linux Programming 14 Linux Programming lt Last Chapter Table of Contents Next Chapter gt Fun Fact The original Apple Macintosh operating system was written in Pascal the ancestor language 5 Ada 14 1 Gnat OS Library Ada Description IC Equivalent leveate_fille Create a Linux file lcreat ESSEN Delete a Linux file unlink etc The gnat OS library gnat os_lib provides common UNIX operations independent of what flavour of UNIX gnat is running on It provides an extensive se
368. og Most businesses or professional institutions have a much more formal structure for their change logs In an environment involving important data a program problem means someone else will have to retrace your activities in order to find and correct a problem Formal logs are kept in a binder since there s always the possibility that a major failure will make it impossible to sign onto the computer Each change is documented with e the date e person who made the software change e what programs were affected e a description of the change Some companies have internal audits done to ensure that changes were properly made The auditors will pick random pages from the change log and ask the programmer to verify the changes In these cases a formal change log may also include information such as the size ownership and permissions of files affected This serves both to quickly check a file as well as to force a programmer to verify the security of the files he or she installs The most common security loopholes in UNIX are caused by people not checking the ownership and permissions of installed files file G Linux http www vaxxine com pegasoft people html book 9 html 1 of 6 7 20 2001 11 32 37 AM Big Online Book of Linux Ada Programming 9 Team Development 9 2 RCS Revision Control System RCS Revision Control System is a tool that shares a document or program source code between multiple people It also automatically numbers the fi
369. ogramming 20 Developing Your Project XFree86 Mach64 3 3 1 14 Creating a new RPM archive is a cumbersome multistep process 20 6 2 TGZ Packages TGZ tar ed gzip packages are created by collecting all the files into one file using tar tape archiver and compressing the file gzip GNU zip or tar s z compress option The files are usually named with tgz ending but sometimes have the tar gz longform ending To create a new tar archive use the cfv options tar cfv archivename file To add additional files to the archive use rfv tar rfv archivename file When the tar file is finished compress it with gzip gzip 9 archivename tar And rename it to tgz mv archivename tar gz archivename tar gz 20 6 3 TAR BZ2 Packages TAR BZ2 tar ed bzip packages are another option Like TGZ these are tar files that are compressed but instead use the new bzip2 command that compresses better than gzip Other Formats TZ is an older format these are tar files that are compressed with the old compression command compress ZIP packages are collected and compressed in the popular PC zip format using zip ZOO packages use an older compression program zoo CPIO Copy In Out is another archiving program similar to tar It collects files but doesn t compress them DEB is a package for the Debian distribution There are a host of other tools and formats including ones to create archives for other platforms 20 7 Man Pages Linux man
370. ogramming 7 Optimizing Your Project The following is the stderr s file for the stderr adb program described elsewhere in this document 2 file stderr adb wienesialena ode Only GNU Ada version 2 9 1 2686 pc linux gnu compiled by GNU C version sud options passed I texttools mcpu i486 march i486 gnatp gnatf TOS i m486 malign loops 2 malign jumps 2 malign functions 2 fno strength reduce fverbose asm options enabled fdefer pop fcse follow jumps fcse skip blocks fexpensive optimizations fthread jumps fpeephole fforce mem trunetron cse Lfinline Luncricns inline ftkeeop statrco consts fealler saves tpcc struct return frerun cse stter loop fschedule insns2 fcommon fverbose asm fgnu linker m80387 mhard tloat mno sofL tloat mieee fp mfp ret 1n 397 mschedule prologue mcpu i486 march i486 malign loops 2 malign jumps 2 malign functions 2 gec2 compiled Section rodata su e string This is an example of writing error messages to stderr align 4 TEOL Tiong Long 54 TEE string This message is on standard error align 4 THOSE Long Lone 33 ECT string This message is on standard output align 4 LC lome ob dong 94 file G Linux http www vaxxine com pegasoft people html book 7 html 8 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Programming 7 Optimizing Your Project
371. ograms similar to Ada Text IO including Open Close Reset Delete Is Open and End Of File However there are no Get or Put procedures Instead there are stream subprograms for working with the data in the file e Stream returns a stream to the file e Read read data from the stream e Write write data to the stream Read and Write are not used directly Instead the attributes read and write will read and write an item to the stream That is Gnat does the necessary conversion to stream data for you For classes of tagged records input and output read and write any child of the class These attributes are implicitly defined for all class wide types that are not also limited As a result you usually combine class with the stream attributes for class input and class output If you don t supply class nothing will be written and no exception will be raised with ada text io ada streams stream io use ada text io ada streams stream io with ada unchecked deallocation procedure class stream is Contact Into A sample elass the base class must not be abstract when using input and output info is tagged null record ptr is access all contact info class type contac type contac type phone number is new contact info with record phone Strang 1 2 14 end record file G Linux http www vaxxine com pegasoft people html book 11 html 27 of 39 7 20 2001 11 33 47 AM
372. ok with Ada Text IO System Address To Access Conversions use Ada Text IO procedure pointers is file G Linux http www vaxxine com pegasoft people html book 8 html 2 of 6 7 20 2001 11 32 24 AM Big Online Book of Linux Ada Programming 8 Debugging Your Project package IntPtrs is new System Address_To_Access_Conversions integer Instantiate a package to convert access types to from addresses This creates an integer access type called Object Pointer five aliased integer 5 Five is aliased because we will be using access types on it Int poinker IntPtrs Object_Pointer This is an Ada access all type int_address System Address This is an address in memory a C pointer begin int pointer five unchecked access Unchecked access needed because five is local to main program If it was global we could use access int address five address Addresses can be found with the address attribute This is the equivalent of a C pointer int pointer t ImnLPLTS DoO Poumwbter ane address 9 int address IntPtrs To Address int pointer Convert between Ada and C pointer types end pointers The gnatG shows the compiler s analysis of your program In this case it displays the results of the instantiation of the generic package with system with ada with ada text io with system address to access conversions use ada text io with system wi
373. olete in Ada 95 by Ada Characters Latin_1 but it s still often used because it s easier to type 10 3 Fundamental Data Types Ada Type Description CEquvaen character Asimgechaacer char nteger AnintgerG2 bi number int Natural Eemorpostiveinegr f Positive fPostivinegr f long Integer A big integer same as long in Gcc long same as int in Gcc Long Long Integer A really big 64 bit integer long long Short Integer A small 16 bit integer short Short Short Integer A really small 8 bit integer char file G Linux http www vaxxine com pegasoft people html book 10 html 4 of 29 7 20 2001 11 33 05 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada Long Float Abigralnmber douve Long Long Float A really big real number long double Short Float A smaller real number ROO Fixed A fixed point real number string An Ada fixed length string char array C There are no built in equivalents of unsigned types Natural and Positive are integer values that aren t allowed to be negative effectively requiring the sign bit to be zero Characters cannot be used for small integer values characters variables can only represent character values Generally speaking programs take data process it in different ways and create new information Data is categorized into different data types Data that is
374. ompletely contained in another Is_Proper_Subset Same as Is_Subset but the bags must not be equal Bags can be bounded dynamic or unbounded Bags are implemented using a hash table To declare a bag a program must provide a hash function for storing items in the bag and must indicate the size of the hash table Here s an example Notice that some of the subprograms are in the Bags instantiation and some in the Bags Unbounded instantiation Also notice the iterator moves over the items but not the duplications with with BC Containers Bags Unboundeg Global Heap package customers is type aCustomerID is new integer range 1 000 9 999 function IDHash id aCustomerID return Positive our hash function package customerContainers is new BC Containers Item aCustomerID create a new controlled tagged record container for customers package customerBags is new customerContainers Bags create a new bag support for our using container type package customerBag is new customerBags Unbounded Hash IDHash Buckets gt 99 Storage_Manager gt Global_Heap Pool Storage gt Global Heap Storage create an unbounded bag package holding customer numbers end customers file G Linux http www vaxxine com pegasoft people html book 18 html 8 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures package bo
375. on on the size of the tables the elements it contains and a hash function and the instantiation provides Get and Set procedures to put values in and take values out of your hash table Gnat 3 11 This version of gnat adds remove and iterator subprograms for hash tables The following is an example using a hash table of integers with text io gnat htable use text io procedure hashtest is gt First define the items TS e Cels C by gnat htable type HashTableIndex is newinteger range 1 200 subtype HashElement is integer EmptyPosition constant HashElement 9999 function HashOf he HashElement return HashTableIndex is begin return HashTableIndex he 91 mod integer HashTableIndex last 1 end HashOf OK instantiate the package file G Linux http www vaxxine com pegasoft people html book 12 html 22 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages IntTable is a simple HashTable of integer Since we re using simple integers the hash key is the integer itself and we can compare integers with equals without having af to write a function to compare the values package IntTable is new gnat htable simple htable Header Num HashTableIndex how big the table is Element gt HashElement what s in the table No Element EmptyPosition what s in empty positions Key HashElem
376. on the word demon It s referred to as a daemon as if a little evil creature was running around doing work on its own If you have a web server running for example you could refer to it s process as the web daemon 13 1 2 Ownership and Permissions For the sake of security all programs belong to an owner and one or more groups In the same way that all users have a login name the owner and a list of groups they belong to every program acts as if it s running on behalf of a particular user and their groups If you re login is bob for example any program you run will be owned by the bob login and whatever groups the bob login belongs to your program can only access files that the bob login can access If a program is owned by the superuser login it doesn t automatically run with the full authority of the superuser This can be circumnavigated by the setuid and setgid permissions When a program is marked with the setuid or setgid active the program is owned by whatever owner and group owns the file This is used for system programs that have to schedule events between multiple people like the printer daemon file G Linux http www vaxxine com pegasoft people html book 13 html 2 of 15 7 20 2001 11 35 51 AM Big Online Book of Linux Ada Programming 13 Linux Introduction 13 2 Using System and OsLib Spawn Often the first question new Linux programmers ask is How to do you run a shell command like Is from a program
377. oop can be exited with exit or exit when Ada allows you to label loops in order to exit out of several loops at once In the following example exit will exit the current loop and all loops up to and including OuterLoop In this case that s both loops OuterLoop while y gt 0 loop while x gt 0 loop A a y if x 37 then exit OuterLoop end if end loop M CON NEC end loop There is a case statement as well for testing a lot of different individual values Ada requires a when others case to file G Linux http www vaxxine com pegasoft people html book 10 html 28 of 29 7 20 2001 11 33 08 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada make sure that all possible cases are handed case DogBreed is when Unknown gt Text IO Put Line I don t know the breed when Shepherd gt Text IO Put Line It s a shepherd when others gt Text IO Put Line It s something else end case Ada also as a null statement which is a placeholder to use when a statement is expected but none is needed For example you can t have an empty if statement there must be at least a null Multiple cases can be included with the vertical bar or a range can be specified with an ellipsis case TaxType is when local tax gt Tax Tax LocalTax when federal tax govt taxable gt Tax Tax FederalTax when others gt null perhaps a warning would be better here instead
378. op Using an enumerated with assigned numbers To get the number we assigned we need unchecked conversion put Error code amp anErrorCode image IOerror put is in position amp integer image anErrorCode pos IOerror file G Linux http www vaxxine com pegasoft people html book 10 html 23 of 29 7 20 2001 11 33 07 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada TOU eae Uae ee put IOerror has a value of amp integer image toInteger IOerror Toad line e Lus put The code before IOerror is put anErrorCode image anErrorCode pred IOerror put line put The code after NONE is put anErrorCode image anErrorCode succ None p r lined m w end enumeration_fun The vowel u has a position of 4 in the list The vowel after a is e Ihe item before German Shepherd is LABRADOR The item after Labrador the region is OTHER Listing of cold regions between Labrador and Other LABRADOR OTHER Error code IOERROR is in position 1 IOerror has a value of 7 Ihe code before IOerror is NONE The code after NONE is IOERROR The boolean type is implemented as an enumerated with two values true and false False is always the predecessor of true C Ada enumerated types have more features than C s You can use pred and succ to move through the list without casting the enumerated as an integer and usin
379. ople to work on different packages and to make packages self documenting Ada packages are divided into two parts The package specification or package spec contains everything that other programs need to use your package It contains all variables they can access all the subprograms they can call etc For subprograms you only use the subprogram header the procedure or function line to let the programmers know the name of the subprogram and what the parameters are C Subprograms declared in package specs are similar to C non static function prototypes in header files Unlike prototypes which are optional declarations in the package specs are required for subprograms to be exported outside of the package package Currency is This package defines US and Canadian dollars and converts money between these two countries subtype aMoney is float type USDollars is new aMoney type CanadianDollars is new aMoney aMoney is separate so we can change the base type if necessary for US and Canadian dollars USDollars and Canadian dollars deliberately incompatible because it could be messy if we mix them up procedure SetExchangeRates USToCanadian CanadianToUS float function ToCanada money USDollars return CanadianDollars function ToUS money CanadianDollars return USDollars file G Linux http www vaxxine com pegasoft people html book 11 html 1 of 39 7 20 2001 11
380. orked else Put_Line Spawn failed end if New_Line end ostest This is an example of the Gnat s OS library Creating a new file Created testfile xxx Getting the timestamp on the file The time stamp is 1998 12 18 23 42 24 Writing to the file file G Linux http www vaxxine com pegasoft people html book 14 html 3 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming Thus x5 tae rirst line im the tile Wrote 34 bytes The file length is 34 Closed the file Locating the file we just made The file as i testfrile xxx Deleting the file File was deleted Running 1s STARTUP dus System map System old Joio boot cdrom dev dosc EC ere home lib lost found mnt opt proc root sbin tmp usr var vmlinuz wma ode End of ls output Spawned worked file G Linux http www vaxxine com pegasoft people html book 14 html 4 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming 14 2 Installing Binding Packages A variety of Ada packages exist to allow you to call C libraries from Ada These packages are called bindings For example there are Ada bindings to Motif TCL WWW CGI and Posix that is the kernel A thin binding gives you direct access to library calls A thick binding provides indirect access where the package does some setup before invoking the library calls The
381. orrect version We deleted the old usr lib gcc lib i486 1linux directory to save some space 11 We installed gnat by running doinstall If we were doing C programming we would need to install the standard C library libstdc as well In this case we enabled C support to avoid recompiling gcc for C in the future Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 2 html 4 of 4 7 20 2001 11 30 05 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s 3 Introduction to the IDE s There are two IDE s or Integrated Development Environments available for gnat and Linux PegaSoft s TIA Tiny IDE for Ada is a text based IDE while GRASP is an X Windows IDE Both have similar basic features On the other hand if you are looking just for text editors with Ada syntax hilighting many exist for Linux including elvis emacs xemacs and nedit 3 1 TIA The Console IDE TIA Tiny IDE for Ada is a console IDE for Gnat Besides being my own program it was written using Gnat runs using the GPL texttools packages described later in this document The screen layout is similar to pico s with the menu options displayed along the bottom of the screen If you are running on the Linux console or a xterm window you can choose the menu items with alt key combinations or using your mouse This IDE is designed for rapid Ada development
382. orts operating systems other than Linux and can also work with Ada compilers other than gnat GRASP is available for download from that GRASP home page at http www eng auburn edu grasp 3 2 1 Installation 1 Download a version of GRASP from the GRASP web site GRASP uses the Motif widget library The static version has a copy of Motif included with it download this version of you don t have a Motif compatible library such as LessTif If you have a Motif compatible library download the dynamic version to save disk space If you are using LessTif make sure that the libXm and related files are properly linked in lib and run ldconfig to ensure Linux sees the changes 2 Move the tar archive to the location you want to install GRASP in For example usr local would be a good choice Oo Unpack the grasp archive with tar xfvz 4 GRASP requires an environment variable called GRASP_HOME to be set so GRASP knows where it was installed To define GRASP_HOME every time for any user add the following line to the end of your etc profile file GRASP HOME graspdir graspada PATH SPATH SGRASP_HOME bin where graspdir is the directory where you installed grasp eg usr local export export file G Linux http www vaxxine com pegasoft people html book 3 html 6 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s Login in again to make the changes take effect and type
383. other computers Each partition has a channel between itself and another partition Of course the partitions can also run concurrently on one computer You describe the partitions and channels using an Ada like language called Garlic GLADE uses rsh to start partitions so make sure you don t run the programs under the root login since root is not allowed to run programs via rsh KB I could install and compile programs with glade but the communication wasn t working error in my networking setup or did I not install it properly 12 14 Basic Math Packages Type Ada Package Description basic math for floating point numbers Generic Ada Numerics Generic Elementary Functions file G Linux http www vaxxine com pegasoft people html book 12 html 29 of 35 7 20 2001 11 34 28 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages basic math for Short host Ada Numerics Short Elementary Functions short float type basic math for Float Ada Numerics Elementary_Functions float type basic math for Long_Float Ada Numerics Long_Elementary_Functions long_float type iii Long Long Floatj Ada Num Sooner or later you will ask the question So how do I compute the cosine of a number The answer found is the Ada Numerics Generic Elementary Functions package This package with the unusually long name is the basic floating point math package This is a generic package that you in
384. ound data dataSize integer number of bytes of sound data dataFormat integer the data format code samplingRate integer the sampling rate channelCount integer the number of channels intkol sibi o2 Iankes dmi od character name of sound end record dataLocation is an offset to the first byte of the sound data If there s no sound name it s 28 the size of the header It can a pointer to the data depending on the dataFormat code but that doesn t apply if you re playing a au file dataSize is the size of the sound data in bytes not including the header dataFormat describes how the sound data is to be interpreted Here is a table of some common values Value Code Format 0 SND FORMAT UNSPECIHED unspecified format SNDFORMAT MLLAW 8 5 bitmuwaw samples 2 SNDFORMAT LINEAR 8 B bilinearsampls B SNDFORMAT LINEAR 16 l6 bit linear samples M X SNDLFORMAT_LINEAR_24 DA4 bitliarsampls B ND FORMATLINEAR 3 2bitlinear samples SS 6 SNDFORMAT FLOAT floating point samples SNDFORMAT DOUBLE double precision float samples 8 SND FORMAT INDIRECT fragmented sampled data l0 SND FORMAT DSP CORE jDSPpogam gt ll SND FORMAT DSP DATA8 B bit fixed point samples 12 SND FORMAT DSP DATA 16 l6 bitfixed pointsamples 13 SND FORMAT DSP DATA24 D4 itfixed pointsamples l4 SND FORMAT DSP DATA
385. ound file to play supply the name of the au file to play au file byteio AFileID the sound file dev dsp byteio AFileID dev dsp device soundbyte short short integer begin Put _Line Playing We au filename amp open the files au_file byteio Open au_filename read gt true dev_dsp byteio Open dev dsp read gt false read until we run out of bytes send all bytes to dev dsp The end of file will cause a seqio error begin ested block to catch the exception loop byteio Read au_file soundbyte byteio Write dev_dsp soundbyte end loop file G Linux http www vaxxine com pegasoft people html book 16 html 33 of 47 7 20 2001 11 37 16 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming exception when byteio seqio error gt null just leave block end close files byteio Close au file byteio Close dev dsp Neo Ne Put_Line All done exception when others gt Put nie OR onlAn exception occurred byteio Close au_file byteio Close dev_dsp raise end playsnd 16 17 3 Using the Mixer You control the mixer chip if your sound card has one by using the ioctl kernel call If there is no mixer the ioctl function returns 1 Mixer Functions Table SOUND_MIXER_NRDEVICES 17 Number of mixer functions on this computer SOUND_MIXER_VOLUME 0 The
386. p ASCII NUL 755 if Result 0 then Pits Line mkdir e god else Put Line temp directory created end if rmdir example remove the directory we just made Result rmdir temp amp ASCII NUL if Result 0 then Pit Tame semelaie esos else Put_Line temp directory removed end if New_Line directory reading DirInfo OpenDir home ken ada amp ASCII NUL Put_Line Directory home ken ada contains these files loop direntop To Pointer ReadDir DirInfo exit when direntop null TellDir returns the position in the directory LastPosition will hold the position of the last entry read Iesu Posts ome POS aon Position s TellDir Ditrintoe y Put_Line Head Direntop name Index Direntop name ASCII NUL amp end loop New_Line SeekDir move to last position in directory Result SeekDir DirInfo LastPosition putr cH plate last position asi M UR direntop To Pointer ReadDir DirInfo Put Line Head Direntop name Index Direntop name ASCII NUL amp New Line RewindDir Start reading again Result RewindDir DirInfo P r orhe first posSitiion als un direntop To Pointer ReadDir DirInfo Put Line Head Direntop name Index Direntop name ASCII NUL amp New Line close the directory file
387. pages are special text files formatted for the groff program GNU run off is based on the older UNIX programs troff for printers and nroff for terminals Troff was originally created in 1973 by Joseph F Ossanna file G Linux http www vaxxine com pegasoft people html book 20 html 3 of 7 7 20 2001 11 38 49 AM Big Online Book of Linux Ada Programming 20 Developing Your Project man pages are text files containing groff markup codes embedded in the text These codes much like HTML tags in a web page control the fonts layout and graphics used in the pages You can also define your own groff codes using groff macros Here s an example of a man page with groff markup codes N This is a comment LH MAN 7 25 July 1993 Lanux ninux Programmer s Manual SH NAME man N macros to format man pages oH SYNOPSIS JB Poft Tascii Xmas I file Here the B groff code indicates that the text that follows should be bold similar to amp lt b amp gt and the SH groff code incidcates the text that follows is a subheading similar to amp lt hn amp gt The groff predefined macros pretaining to manual pages are documented in the section 7 manual page on man man 7 man All the man pages are stored in subdirectories in usr man The subdirectories are numbered each number representing a different section number of the Linux manual The manuals sections include 1 Linux introduction 2 System Calls 3 C Library
388. part of the standard C library and they don t need to be linked in with the lc option 16 3 1 Basic time functions The basic Linux time functions work with the number of seconds since January 1 1970 This is referred to as the epoch in the Linux man pages Because of the limits of a long integer value the Linux clock will stop working properly around the year 2038 The basic functions use a long integer for the time type time t is new long integer procedure time time in out time t pragma import C time Returns the current time function difftime timel time2 time t return long float pragma import C difftime Returns the number of seconds between two times as a long float 16 3 2 Timeval Calls Microsecond Accuracy The timeval kernel calls return or set the current time with microsecond accuracy using a timeval record type timeval is record tv sec time t number of seconds since epoch tv usec long integer number of microseconds end record type timezone is record tz minuteswest integer minutes west of Greenwich tz dsttime integer unsupported in Linux end record procedure gettimeofday result out integer tv in out timeval tz in out timezone pragma import C gettimeofday pragma import valued procedure gettimeofday Get the current time as the number of microseconds since January 1 1970 Returns 0 for s
389. pec the procedure that elaborates a package spec Enum_Rep the numerical value of an enumerated identifier Fixed_Value unchecked conversion of integer to a fixed type Img shorthand for image Integer_Value the reverse of Fixed_Value Machine_Bits for compatibility with other Ada compilers Max_Interrupt_Priority the maximum interrupt priority Max_Priority the maximum task priority Maximum_Alignment determine the bit alignment of an external object Mechanism_Code how a parameter is passed to a subprogram Null_Parameter for passing null pointer for a composite object Object_Size for fixed and discrete types default allocation size Passed_By_Reference true if type is normally passed by reference file G Linux http www vaxxine com pegasoft people html book 10 html 14 of 29 7 20 2001 11 33 06 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada Range_Length number of values in a discrete type Storage_Unit same as System Storage_Unit Tick same as System Tick Type_Class return type basic class of an identifier such an enumerated or array Universal_Literal_String return a string literal for a number Unrestricted_Access like access but has no accessibility or aliased view checks Value_Size number of bits to represent a value of a given subtype Word_Size same as System Word_Size The following program demonstrates some of the basic Ada attributes with text_io
390. procedure attrib is type enum is dog mica megabyte begin Text IO Put Line Some Basic Ada Attributes Text IO New Line Text IO Put Line Boolean bits is amp boolean size img Text IO Put Line Short short integer bits is amp short short integer size img Text IO Put Line Short integer bits is amp short integer size img Text IO Put Line Integer bits is amp integer size img Text IO Put Line Long integer bits is amp long integer size img Text IO Put Line Long long integer bits is amp Text IO Put Line Text IO Put Line Text IO Put Line Text IO Put Line Text IO Put Line Text IO Put Line long long float Text_IO Put_Line m a Lex m J LCXU mm j dee mm ies ESX E Lex 1 exu TSE TEXT IO TO TOR IO TOR TOR TO enum size img TO New_Line IP Ul Pu eu eu Pu Pu dus i fy E Je S Line _ Line _ Line New_Line _ Line _Line Line long long integer size img Natural bits xe amp natural size amg s Positive bits is amp positive size img Short float pits ls Ys Shooemtloat e sazie ime 7 Roots sus T g Loar size me Long float bits ais Son float size img Long long loat bits is amp size img Our 3 item enumerated bits is amp First integer is amp integer first img Last integer i
391. programs are labeled with the package name a double underscore and the subprogram name Need to clean this up KB Elat profile Each sample counts as 0 01 seconds S cumulative self self total time seconds seconds callsus callius callname 62 500 050 05 mcount internal 22 9 9 0 8 On Or O Zine One UE file G Linux http www vaxxine com pegasoft people html book 6 html 6 of 14 7 20 2001 11 31 54 AM Big Online Book of Linux Ada Programming 6 Development Utilties 1A DOO OS Or 0 3130 O OOO OOO OO ae E ESO le OS Eel 000 080 0010 00 10000 00 ada bench2 0 000 080 0010 000 00Tact elapse the percentage of the total running time of the time program used by this function cumulative a running sum of the number of seconds accounted seconds for by this function and those listed above it self the number of seconds accounted for by this seconds function alorne This is the major sort for this listing calls the number of times this function was invoked if this function is profiled else blank self the average number of milliseconds spent in this ms call function per call if this function is profiled else blank total the average number of milliseconds spent in this ms callfunction and its descendents per call if this function is profiled else blank name the name of the function This is the minor sort for this listing The index shows the location of the function in the gprof listing If the index i
392. r SIGTERM Current Handler gives a callback to the handler Handler all run the handler callback if EMERGENCY_SHUTDOWN then Put_Line Handler works else Put tine ABL xtd e doesn t worki end if test complete reset emergency shutdown flag EMERGENCY SHUTDOWN false zx ce Once oom New Line Put Line The number is amp Counter img loop exit when EMERGENCY SHUTDOWN Counter i omis c No Put Line Doubling the number is amp Counter img delay 1 0 end loop Put Line The program has shut down end SigDemo This program demonstrates signal handling Lg stop this program tyge Control C or kill it with the shell kill command The SIGTERM handler isn t reserved There is a SIGINT handler installed Testing SIGTERM handler HandleKill Program is shutting down Handler works The number is 2 Doubling the number is 4 file G Linux http www vaxxine com pegasoft people html book 14 html 9 of 15 7 20 2001 11 36 19 AM Big Online Book of Linux Ada Programming 14 Linux Programming Doubling the number is 8 Doubling the number is 16 Doubling the number is 32 Doubling the number is 64 Doubling the number is 128 Doubling the number is 256 Doubling the number is 512 HandlePowerFailure Program is shutting down Ihe program has shut down 14 4 Working with the Command L
393. r CPUs such as Pentiums Under GCC 2 8 1 and Gnat the GCC FAQ recommends the following switches for reasonable Pentium performance m486 malign loops 2 malign jumps 2 malign functions 2 fno strength reduce There are other switches that may or may not be helpful depending on your program read the gcc FAQ for full details IDE TIA sets the proper switches for you based on your selections in the project parameters window Let s put all these flags together Suppose you are trying to develop a program for the Intel Pentium CPU with an emphasis on speed During development the Gnatmake switches would be O1 since this setting suppresses pragma optimize warnings For the final release the Gnatmake switches should be m486 O3 malign loops 2 malign jumps 2 malign functions 2 fno strength reduce gnatp for maximum performance on a Pentium processor 7 4 What Difference Does Optimization Make In the previous sections we saw GCC compiler switches and and Ada pragmas that affect the speed and size of your finished application But how much of a difference does optimization make And are there any problems caused by optimization The optimization switches and pragmas affect different applications differently Some will give better results to certain kinds of applications while others may actually have a negative effect The following table summarizes the results of optimizing on the Hartstone Ada benchmark program Hartstone i
394. r of a program is referred to as the UID user identification number Under Linux there are actually three owners to any given program the effective UID the real UID and the saved UID Normally these three are all the same login The real and saved uids are provided for programs that must temporarily pretend to be somebody else like a daemon that needs special login for a short period of time or setuid setgid programs that must temporarily switch between owners These special file G Linux http www vaxxine com pegasoft people html book 16 html 7 of 47 7 20 2001 11 37 13 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming functions are not covered here function getuid return integer pragma import C getuid Get the real UID of a process Example Put Line My UID is amp getuid img function setuid uid integer return integer pragma import C setuid Change the effective and saved and real UID of a process to a new owner The GID group identification number is the group the program belongs to In Linux there s a main effective group number and any number of secondary groups that a program can belong to There is also real and saved GIDs just like UIDs procedure getgroups result out integer num integer gidlist pragma import C getgroups pragma import valued procedure getgroups Return a list of group numbers that a process belongs to Gidlist is the address of
395. r or not gnatn or gnatN has been used Pragma Discard_Names frees up space by discarding the ASCII images names of identifiers For example if you have a big enumerated type Ada normally maintains strings for the names of each of the enumerated items in case you want to use the img attribute You can discard these names if you never intend to use img type aDogBreed is Unknown Boxer Shepherd MixedBreed pragma Discard Names aDogBreed When you discard names the img is still available Instead of returning the enumerated value s image img returns the position of the enumerated type for example 0 1 2 and so forth Fun Fact The ASCII images of your variable names are stored as C strings at the end of your executable file You can view them using the less or strings shell command 7 3 CPU Optimization Options There are two main CPU optimization switches in GCC 2 x as listed in the GCC manual mno 486 optimize for 80386 m486 optimize for 80486 These programs will still run on a 80386 file G Linux http www vaxxine com pegasoft people html book 7 html 3 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Programming 7 Optimizing Your Project Future versions of Gnat built for GCC 3 x or later will probably support e mpentium optimize for Pentium Intel 586 e mcpu i686 optimize for Pentium II Intel 686 e mcpu k6 optimize for AMD K6 There are currently no switches newe
396. raise end New Line spd new Sales Record salesman code gt 1 sales amount gt 55 50 Debug Pool Exception 4 begin Put Line Freeing deallocated access type is an exception Put Line spd new Sales Record Put laine spd spd j Put_Line Free spd Put_Line Free spd2 S2 mU spd Free spd Free spd2 exception when System Debug Pools Freeing Deallocated Storage gt Put Line Freeing Deallocated Storage raised when others gt Put Line Unexpected exception raise end New Line end debpools Program Result Fun with debug storage pools Accessing a non allocated access type is an exception Spd salesman code 1 Accessing Not Allocated Storage raised Freeing a non allocated access type is an exception Spd2 sr access not allocated in pool Free spd2 Freeing Not Allocated Storage raised Accessing deallocated access type is an exception spd new Sales Record Free spd Spd salesman code 1 Accessing Deallocated Storage raised Freeing deallocated access type is an exception spd new Sales Record spd2 spd Free spd Free spd2 Freeing Deallocated Storage raised file G Linux http www vaxxine com pegasoft people html book 11 html 19 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming To create your o
397. ray Put Line The element is amp ip all img New Line increment example Increment ip Put Line Incrementing the pointer it now points at amp oracio New Line decrement example Decrement ip Put Line Decrementing the pointer it now points at amp ip all inmg RP New Line addition example ip f Iip t 3 Put_Line Addition moves the pointer forward Put_Line Moving forward three elements it now points at amp apealil img New_Line subtraction example ip 1p 2 Put_Line Subtraction moves the pointer backwards Put_Line Moving backwards two elements it now points at amp ip all img New Line Virtual Length examples E Put_Line Virtual_Length gives the length from the pointer to the Put Line default terminator The length from this position is amp Virtual Length ip img amp positions Put Line Virtual Length can also use an arbitrary terminator Put Line The length from the pointer to the first 14 is amp vVirtual_Length ip 14 img amp T positions EP New_Line Value examples P t_Line Value returns the array Slice from the pointer position to J Put_Line the terminator The array value from this position is ShowArray Value ip file G Linux http www vaxxine com pegasoft people html book 17 html 5 of 11 7 20 2
398. rce file with conditional directives a file with variable assignments for the conditional directives and produces a source file with all statements not satisfying the conditional directives removed C The conditional directives do not allow expressions There must only be a variable and that variable must be true or false IDE No IDE s currently support gnatprep file G Linux http www vaxxine com pegasoft people html book 6 html 3 of 14 7 20 2001 11 31 53 AM Big Online Book of Linux Ada Programming 6 Development Utilties Suppose you create a file called prepvalues with the following Gnatprep definitions ALPHAVERS ION true BETAVERSION false RELEASEVERSION false TRANSLATION English Suppose also that you had a short program with Gnatprep statements in it with text_io use text io procedure preptest is only include the relevant parts for this version dif ALPHAVERSION s version s string s aloha elsif BETAVERSION S version string beta elsif RELEASEVERSION S version string release else s_version string unknown end if string is the value of the gnatprep variable named translation S bErahnslsbronm String 2 STRANSLATION begin Put_Line This is the amp s_version amp edition Put_Line This is the amp s_translation amp translation end preptest Running gnatprep on the above program with the prep
399. rces in current directory O 0123 Control the optimization level Fgnata Assertions enabled Pragma Assert Debug to be activated enatA Avoidprocessing gnat adc if present file will be ignored gnatb Generate brief messages to stderr even if verbose mode set gnate Check syntax and semantics only no code generation Fgnatd Compiler debug option a z A Z 0 9 see debug adb FgnaD Debug expanded generated code rather than source code Fgnate Emormessages generated immediately not saved up tillend FgnaE Dynamic elaboration checking mode enabled Fgnatf Fullerrors Verbose details all undefined references FgnaF Foreallimpor exportextemal names to all uppercase gnatg GNAT implementation mode used for compiling GNAT units FgnaG Output generated expanded code in source form Fgnah Output this usage help information Fgnai identifier char set 1 2 3 4 8 pifiniwy Fgnak Limit file names to nnn characters k kranch 0 Fgnal JOutputfull source listing with embedded error messages FgnaL Use longjmp setjmp for exceptionhandling gnatmnnn Limitnumberofdetected errors to nnn 1 099 Fgnato Enable overflow checking off by default FgnatOnm Set name of output ali file internal switch file G Linux http www vaxxine com pegasoft people html boo
400. re found m update dependancies without compiling n check dependencies but don t do anything 0 name save the executable as name q quiet no status messages s switch change recompile if the switches have changed v verbose explain why files are compiled aldir besides the directory of the first file search directory dir for source files aOdir besides the directory of the first file search directory dir for object and ali files Adir same as aldir and aLdir Idir same as aodir aldir I don t look for source files in the directory of the first file Ldir besides directory of the first file look for libraries in directory dir Cargs s pass switches s to compiler bargs s pass switches s to binder largs s span gt pass switches s to linker e g largs somefile o to link in the somefile object file 4 7 1 So you changed the comments Use gnatmake with the m option which updates gnat s files without producing a new object code file Use this to avoid pointless recompilations when all you changed were the comments in a source file lt Last Chapter Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 4 html 8 of 8 7 20 2001 11 31 15 AM Big Online Book of Linux Ada Programming 5 Building Large Projects 5 Building Large Projects lt Last Chapter Table of Contents Next Chapter gt 5 1 Make The Traditional Project Buil
401. reams a variation of Ada Sequential IO for reading and writing C sequential files Ada Streams Stream IO C Streams a package for reading and writing C streams Ada Text IO C Streams a package for reading and writing C text files Ada Wide Text IO C Streams a package for reading and writing 16 bit character C text files file G Linux http www vaxxine com pegasoft people html book 17 html 10 of 11 7 20 2001 11 37 39 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada 17 6 A Word on Interfaces Fortran Gnat provides interfacing packages for languages besides C Interfaces Fortran contains types and subprograms to link Fortran language programs to your Ada programs The GCC Fortran 77 compiler is g77 As with gcc most of the Fortran data types correspond identically with an Ada type A Fortran real variable for example is the same as an Ada float and a double precision variable is an Ada long_float Other Ada compilers may not do this if portability is an issue always use the types of Interfaces Fortran Gnat 3 12 introduces a proper Fortran logical type that behaves according to Fortran semantics Fortran subprograms may be imported into Ada using pragma import procedure MyFortranSubroutine pragma import Fortran MyFortranSubroutine Variables may be likewise imported RealVar float pragma import Fortran RealVar g77 adds an und
402. rent project under a new name creating a new project Open Selected File opens hilighted source file in the project window Remove Selected Files deletes these files from the project window Add Files to Project add source files to the project window The Search Menu search for files to add to the project The Preferences Menu Colour Font change the appearance of the source code window Tab Size change the number of spaces to indent when the tab key is pressed Generate gml files NQS KB The Window Menu Message Window opens the GRASP error message window file G Linux http www vaxxine com pegasoft people html book 3 html 7 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s Search Window opens the file searching window 3 2 4 Source File Window This is the window where you type up your Ada programs and packages The File Menu Clear erase the entire source file Open open a new source file Save save the source file Save as save the source file under a new name Print prints the source file to a postscript printer or to a file to be printed with ghostscript Language change the source file language This doesn t translate the file to a new language but tells GRASP how the file should be hilighted Exit closes the source file window The Edit Menu Undo undoes last edit change Cut Copy Paste standard cut copy and pasting text Paste Prim
403. ring pragma import C asctime Convert the tm into a standard UNIX time C string such as you see with the Is 1 shell command function ctime time in out time t return long integer pragma import C ctime Get the current time as a standard UNIX time C string It s equivalent to using asctime on the localtime of the current time procedure strftime result size_t datestr in out stringtype max size t format string tm in out tmrec pragma import C strftime Like asctime converts a tm time into text strftime uses formatting codes to determine the appearance of the text similar to the shell date command Returns the length of the date string including the ending ASCILNUL See the man page for complete details Example datestring string iy 20 statftime datestringsize datestring datestring size 8 I M amp ASCII NUL tm Ada Text IO Put Line The time is amp datestring l datestringsize 1 16 3 5 Timer Functions Timer functions use the timeval structure function timerclear tv timeval function timerisset tv timeval function timercmp t0 tl timeval operator 16 4 Process Information The Linux process functions are part of the standard C library and do not need to be linked in with lc function getpid return integer Returns the Process Identification Number PID for your program 16 4 1 Ownership The owne
404. rings Wide Maps Wide version of strings maps a stwise Ada Strings Wide Search Internal Use a stwiun Ada Strings Wide Unbounded Wide DBQUHOSEHSIIHES package a suteio Ada Strings Unbounded Text_IO Unbounded strings package a swmwco Ada Strings Wide_Maps Wide_Constant Upper set Pu Dus other wide char mappings file G Linux http www vaxxine com pegasoft people html book 99_f html 4 of 9 7 20 2001 11 40 56 AM a stunau Ada Streams Unbounded Aux Big Online Book of Linux Ada Programming Appendix F ism ta Sings Wide Unbounded Wide Text JO s totonde datae package besytaco Ada Synchronous Task Control REN ISP OHIO a tags Ada Tags Standard Ada tag package a tasatt Ada Task Attributes ISet get task attributes a taside Ada Task Identification Task ID package y foe for formatted a teioed Ada Text_IO Editing Text IO o Ada Text IO on generic Text IO package ico to Text 10 Complex Aux Es pone tone complexa package a ticoio Ada Text IO Complex IO Generic Teri IO paese tor complex numbers fa tideau Ada Text_IO Decimal_Aux Internal Use a tideio Ada Text IO Decimal IO Internal Use fa tienau Ada Text IO Enumeration Aux Internal Use a tienio Ada Text IO Enumeration IO Internal Use a tifiio Ada Text_IO Fixed_IO Internal Use a tiflau Ada Text IO Float Aux Internal Use a tiflio Ada Text_IO Float_IO Internal Use fa tigeau Ada Text_IO Generic_Aux Internal Use fa
405. riting amp line2write amp with fwrite file G Linux http www vaxxine com pegasoft people html book 17 html 9 of 11 7 20 2001 11 37 39 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada amountWritten fwrite line2write address what to write i size ot elements line2write length how many to write Tcl to wAlch file Put_Line Wrote amp amountWritten img amp characters New_Line Put _Line writing with fputs J result fputs cline2write address fd Put Line Result was amp result img New Line result felose td Put_Line Closed amp path amp with fclose Put Line Result was amp result img unlink cpath address Put Line Deleted amp path amp with unlink Result was amp result img end cstreamtest This is an example of Interfaces C Streams Opened testfile xxx with fopen Writing This is a test with fwrite Wrote 14 characters Writing with fputs Result was Closed testfile xxx with fclose Result was 0 Deleted testfile xxx with unlink Result was 0 17 5 Ada and C Files Gnat provides several interfacing packages to allow Ada to read and write C files These are a thicker binding than Interfaces C Streams e Ada Direct IO C Streams a variation of Ada Direct IO of reading and writing C direct files Ada Sequential IO C St
406. rld before TIA s window reappears 4 2 2 Writing a Program without an IDE With a standard UNIX editor such as pico or vi create the following file called hello adb For example pico hello adb Type in the following Ada program with text io use text 10 procedure hello is begin put line Hello World end hello This Ada program will print a short message on the screen When the file is saved the gnatmake command to build the project gnatmake hello adb file G Linux http www vaxxine com pegasoft people html book 4 html 2 of 8 7 20 2001 11 31 15 AM Big Online Book of Linux Ada Programming 4 From Source Code to Executable If there is a problem with your program gnatmake will show you the line number the position on the line and an error message describing the problem If you typed in the program correctly you should now have an executable file called hello Run the file by typing herno or hello on some distributions and Linux will respond by displaying the message Hello World 4 2 3 After Building After building your project there should be several files in your directory e hello adb this is the Ada program you typed in The is called a source file e hello o this is the binary code created by the compiler This is called an object file e hello ali this is additional information about the program created by gnat e hello this is the executable program If you want to clean up your d
407. rn FILES LES Orset slong onm aimes int return ane Move offset bytes from the specified origin point function ftell stream FIL Get stream offset for fseek function f return siz Write count bytes function i write buffer v e t satty handle in Es return long Oids size size t count size t stream FILESs from a buffer of count length and return the number of bytes actually written t return int NQS determine if stream is a TTY device KB procedure mktemp template chars Create a random name for a temporary file procedure rewind stream F Move to the start of the stream function s ghee TLES etvbuf stream F ILEs buffer chars mode int size size_t return file G Linux http www vaxxine com pegasoft people html book 17 html 8 of 11 7 20 2001 11 37 39 AM Big Online Book of Linux Ada Programming 17 Moving C Programs To Ada NQS used to know what this did KB procedure tmpnam string chars Difference with tmpnam KB The parameter must be a pointer to a string buffer of at least L_tmpnam bytes the call with a null parameter is not supported function tmpfile return FILEs NQS KB function ungetc c int stream FILEs return int Back up one character in the stream function unlink filename chars return int Delete a stream file The followi
408. rned in the LastError variable LastError is 0 if there is no error OS this package contains subprograms for working with the Linux operating system that is for reading the current time deleting files and the like Texttools pathnames are defined in this package A path is a Str255 string The OS package can define path prefixes beginning with a For example HOME is predefined as the user s home directory To delete a file called temp txt from the user s home directory you can use the OS erase command Erase Do255 SHOMB tenp txt Je file G Linux http www vaxxine com pegasoft people html book 15 html 4 of 13 7 20 2001 11 36 37 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings SYS is another predefined prefix This refers to a directory in the user s home directory named with the short name you specify in the StartupCommon procedure Sounds keyboard macros and the session log file are located here UserIO this package contains all the input output routines for TextTools it handles mouse clicks draws text and so forth Normally only people writing controls will need access to this package However the pen colours beep sounds and text styles are also defined here Controls this package contains all the window controls and related subprograms Currently defined controls are Thermometer ScrollBar StaticLine EditLine and family CheckBox RadioButton WindowButton Rectangle L
409. roc man page 13 5 4 AudioCD An Example Program The following CD ROM audio CD player illustrates kernel calls a standard C library function and using a device file with Ada Text IO System use Ada Text IO procedure audiocd is Sample program for playing audio CD s file G Linux http www vaxxine com pegasoft people html book 13 html 8 of 15 7 20 2001 11 35 52 AM Big Online Book of Linux Ada Programming 13 Linux Introduction DIR INCITS This section deals with device files in particular the cdrom device DevCDROM constant string dev cdrom path to the CDROM device usually dev cdrom type ioctlID is new integer type aFileID is new integer Define these as separate types for error checking A ioctlID is never the same as a FileID type byte is new integer range 0 255 for byte size use 8 CDROMPLAYTRKIND constant ioctlID 16453044 CDROMSTOP constant ioctlID 16453074 CDROMSTART constant ioctlID 16 5308 various CDROM ioctl functions as mentioned in the CDROM documentation in usr doc kernel type aDummyParam is new integer define this as a separate type to make sure nothing important is used as a third parameter to ioctl noparam a version Of ioctl for functions that Gon Vt use a third parameter procedure ioctl nopar
410. rror number procedure perror s string pragma import C perror print the last kernel error and a leading C string procedure PutIPNum ia alInAddr is divide an IP number into bytes and display it IP unsigned ia addr Bytel Byte2 Byte3 Byte4 unsigneg file G Linux http www vaxxine com pegasoft people html book 16 html 41 of 47 7 20 2001 11 37 17 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming begin Byte4 IP mod 256 IP IP 256 Byte3 IP mod 256 ip f XE 256 Byte2 IP mod 256 Bytel IP 256 Put Byte4 img Put Tem ee Put By ees ame Paaie ee Put Byte2 img Ione ee ee Put Bytel img end PutIPNum procedure SendHTTPCommand soc aSocketFD cmd string is Write a HTTP command string to the socket amountWritten integer 0 totalWritten integer 0 position integer cmd first begin loop Write amountWritten soc cmd position address cmd length integer totalWritten if amountWritten lt 0 then Put_Line Standard Error Write to socket failed return end if Put Line Sent amp amountWritten img amp bytes totalWritten totalWritten amountWritten position position amountWritten exit when totalWritten cmd length end loop end SendHTTPCommand procedure ShowWebPage s Read amount
411. rs 20 5 Releasing Your Software Check list Did you remove all pragma Normalize_Scalars Did you remove all access type references to debug pools 20 5 1 A Third Party Library If you want to release a package as a third party library Change your ads files to read only with chmod w Collect your executables into an archive with the ar command see the section on libraries above Include instructions for installing the archive and make sure you mention that those who use your library must use the f option for gnatmake This option treats all read only files as third party libraries that cannot be recompiled because the package bodies were not included 20 6 Distribution Formats 20 6 1 RPM Red Hat Package Manager RPM Red Hat Package Manager is the most popular installation tool It installs uninstalls and checksums packages S u S E s YaST Yet Another Setup Tool works using RPM RPM files end in rpm Full details on the RPM format are available from Red Hat s RPM site at http www rpm org The q command checks for a package a shows all installed packages root redbase root rpm q uucp uucp 1 06 1 14 root redbase root rpm q kernel kernel 2 0 32 2 root redbase root rpm q a setup 1 9 1 1 filesystem 1 3 1 2 basesystem 4 9 1 AnotherLevel 0 5 2 Idconfig 1 9 5 2 file G Linux http www vaxxine com pegasoft people html book 20 html 2 of 7 7 20 2001 11 38 49 AM Big Online Book of Linux Ada Pr
412. s amp integer last img First enumerated is amp enum first img Last enumerated is amp enum last img Mica is in position amp enum pos mica img The third enumerated is amp enum val 2 img file G Linux http www vaxxine com pegasoft people html book 10 html 15 of 29 7 20 2001 11 33 06 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada Text IO New Line Text IO Put Line The smallest float is amp float small img Text IO Put Line The largest float is amp float large img Text IO Put Line The number of digits in float is amp integer image float digits Text IO Put Line The size of the mantissa in bits is amp float mantissa img Text IO Put Line However the CPU s mantissa is amp float machine mantissa img end attrib Here are the results of the program on a Pentium II with gnat 3 11 Some Basic Ada Attributes Boolean bits is 1 Short short integer bits is 8 Short integer bits is 16 Integer bits is 32 Long integer bits is 32 Long long integer bits is 64 Natural bits is 31 Positive bits Iis 31 Short float bits 18 32 Ploat bits is 32 Long float bits is 64 long long r boat bats a9 2 Our 3 item enumerated bits is 2 First integer is 2147483648 Last integer is 2147483647 First enumerated is DOG Last enumerated is MEGABYTE Mice 1S an position i The third
413. s To Be Completed Access access value for an identifier Address address value for an identifier Adjacent the floating point value adjacent to the given value Aft for fixed types number of decimal digits after decimal to accommodate a subtype Alignment storage value of an identifier Base unconstrained subtype of a type Bit Order whether or not bits are high order first Body Version NQS Callable true if task can be called Ceiling round up a floating point value Class classwide type of an identifier Component Size size of array components in bits Compose Constrained Copy Sign Count Definite Delta Denorm file G Linux http www vaxxine com pegasoft people html book 10 html 12 of 29 7 20 2001 11 33 06 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada Digits Exponent External_Tag First first index in an array First_Bit Floor round down a floating point value Fore Fraction Identity Image Input convert value to a string Last last index in an array Last_Bit Leading_Part Length number of elements in an array Machine Machine_Emax maximum real type exponent on your hardware Machine_Emin minimum real type exponent on your hardware Machine_Mantissa size of mantissa on your hardware in bits Machine_Overflows true of your machine overflows real types NQS Machine_Radix Machine_Rounds Max maximum value Max_Size_In_Storage_Elements Min minimum va
414. s in parenthesis it shows where it would appear in the gprof listing if it were to be printed Call graph explanation follows granularity each sample hit covers 4 byte s for 100 00 of 0 01 seconds index time self children called name 499500fact factorial 1 0 010 001000 1000 ada bench2 3 file G Linux http www vaxxine com pegasoft people html book 6 html 7 of 14 7 20 2001 11 31 54 AM Big Online Book of Linux Ada Programming 6 Development Utilties OOOO ORO COMO OOS ASS SCO 3E Ne iE EO EO 1 0 000 0007 0meounmt 177 49 9500tacE factorial 1 0 000 00070 stare 4273 2 100 00 000 01lmain 2 0 000 01171 ads bench r3 0 000 000 0 gnat initialize 399 0 000 000 0adainit 61 0 000 000 0 gnat break start 395 0 000 000 0adafinal 60 0 000 000 0 gnat finalize 397 DoD 90D DET 95 0 000 0117 1maim 2 3 100 00 000 011 ada bench2 LS DI 200 100071000 Fact reactors E 0 000 000 0mcount 177 file G Linux http www vaxxine com pegasoft people html book 6 html 8 of 14 7 20 2001 11 31 54 AM Big Online Book of Linux Ada Programming 6 Development Utilties 0 000 001 1adasrnzt G1 61 0 00T 0O00 00 1E3E Suede elabb 6 0 000 000 0mcounmt 177 This table describes the call tree of the program and was sorted by the total amount of time spent in each function and its children Each entry in this table consists of several lines The line with the ind
415. s package is defined a special tagged record called Controlled When you extend this tagged record you can overload special procedures that Ada will automatically execute when necessary This saves you from having to explicitly call such procedures yourself type businessDepartment is new Finalization Controlled with record departmentHead aEmployeeProfilePtr new aSalaryEmployee Bob Smith age gt 45 rate gt 42 000 0 end record In this example every time you allocate a businessDepartment variable DepartmentHead is initialized with a dynamic allocation We could write a procedure to free up this memory but then we would have to remember to call it every time a variable is about to be discarded A better way to handle this is to let Ada do the discarding for us Finalize is the name of the procedure Ada calls when cleaning up a controlled tagged record We create our own Finalize for our businessDepartment tagged record procedure Finalize bd in out businessDepartment is begin Finalize Free bd departmentHead end Finalize Now Ada will automatically run this procedure before any businessDepartment variable is destroyed and we never have to worry about forgetting to free up the memory used by departmentHead C Finalize is the destructor There are two other such automatic procedure we can use with controlled tagged records Procedure Initialize is used when an object is first created a
416. s a multithreading mathematics test available freely on the Internet http ftp sunet se pub4 benchmark hartstone Table Hartstone 1 1 Benchmark Summary Gnat switches Ada pragmas CPU Time File Size FgnatE gnato g 0 13s 94265 FgnatE gnao 0 13s 14743 FgntE 0 10s 1138679 0 32 noswiches 0 10s 1138679 0 2096 FO b pos Boae 0 22 Task Set Util 0 41 0 41 file G Linux http www vaxxine com pegasoft people html book 7 html 4 of 10 7 20 2001 11 32 11 AM Big Online Book of Linux Ada Programming 7 Optimizing Your Project 02 Fo 078 a 0 22 8 2 0 07s 1187900 20 FO3 gnatp Pent a Max F 0 05s 105714 0 1596 Qn Space 0 05s 11057144 0 1596 Max Optimize Time o 05s 105714 0 1596 Max 0 lis 105712 Pent GCC Pentium optimization switches Max Pent ffast math fomit frame pointer This test was conducted with a Pentium II 350 64 Megs RAM and ALT Gnat 3 12p 9 As they say your milage many vary and probably will By optimizing the application Hartstone can be reduced to half its size and run about 2 3 faster than using no optimization However if we pack the arrays in Hartstone we save two bytes but lose all the improvements in speed Sometimes smaller programs are not faster Let s try optimizing a convoluted program that uses integers arrays functions and mathematics and see what effect the optimization
417. s defined but that doesn t mean that there are actually 32 serial port on the computer You will have to open the device and check for an error if it does not exist For example opening dev lpl and writing a file to it writes the file as raw data to the first parallel port printer Information on how these devices work is usually found in the How To s and other system documentation Special functions specific to a device are programmed with the ioctl function For example you d use ioctl on dev dsp to set the sound volume on your sound card The documentation for device files are often difficult to find Sometimes documentation is contained in the kernel documentation the usr doc kernel directory or in the kernel C header files the usr src linux include directories A list of some of the ioctl operations are listed in an appendix 13 5 3 Proc File System The proc directory isn t really a directory at all That is it s a fake directory that s not physically on the hard disk but you can still look into it and open the files it contains The proc file system contains system information that you can access by opening the files and reading them Some proc files may be written to in order to change system settings For example there are files that give you the information on how busy the CPU is how much free memory you have and the environment variables for the current process The contents of these files are described in the p
418. s is an example of perror and strerror New Line make a deliberate error and print it with perror Put Line Trying to link a non existent file to itself LinkResult Link blahblah blahblah if LinkResult 1 then perror Link Tailed 9 end if New_Line Retrieve the last error message with strerror Because strerror returns a C string only print the SEEING Up to the first NUL Character ErrorMessagePtr StrError Errno NullLocation Index string ErrorMessagePtr all Put The last error message was Put Head string ErrorMessagePtr all NullLocation 1 iEnbhe oae o MM VE end perr amp ASCII NUL file G Linux http www vaxxine com pegasoft people html book 16 html 4 of 47 7 20 2001 11 37 13 AM Ve Big Online Book of Linux Ada Programming 16 Advanced Linux Programming This is an example of perror and strerror Trying to link a non existent file to itself Link failed No such file or directory The last error message was No such file or directory A table of error numbers is in the appendix 16 3 The Linux Clock The Ada Calendar package is the standard method of working with time in Ada programs If you need to interface with C programs you may need to use Linux s time features The Linux clock functions are either kernel calls or are a
419. s since you always write at the end of the file The following program writes a couple of customer records to a sequential file and reads them back again with Ada Text IO Ada Sequential IO Ada IO Exceptions use Ada Text IO procedure sequentio is Ada Sequential IO example type aCustomer is record file G Linux http www vaxxine com pegasoft people html book 12 html 8 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages name s Ste re shine ee AON 5 amountOwing float 0 0 end record a customer record with two fields package aCustomerFile is new Ada Sequential_IO aCustomer use aCustomerFile instantiate a new package for sequential IO on a file of customer records CustomerFile aCustomerFile File Type our customer file use aCustomerFile because Text IO and Sequential IO have File Type cr aCustomer begin Put Line This is a Ada Sequential IO example New Line create the fil Create CustomerFile Mode Out File Name gt customer seg display some statistics Put Line We created the file amp Name CustomerFile Put Line We re currently using amp Mode CustomerFile img amp mode if Is Open CustomerFile then put Line The file is open else Put_Line The file isn t open end if New_Line write the first re
420. ss Identification Here s a typical output from the ps command ps 12 IBS DAP Ne TIME CMD SUS weil OO OOOO Mlogam 58 Si Ers 00 00 00 bash Sb wee slt 00 QOIS PPID s Processes also have a PPID Parent Process ID for identifying its parent process The ps command option for long shows additional information about a process including its PPID ps l E S UID IAD IPI ECTS INL IBID SZ WCHAN TTY TIME CMD OOS 0 5 79 1 0 60 0 549 wait4 ttyl 00 00 00 Logan file G Linux http www vaxxine com pegasoft people html book 13 html 1 of 15 7 20 2001 11 35 51 AM Big Online Book of Linux Ada Programming 13 Linux Introduction TIONES 0 589 S79 Or xa 0 457 wait4 ttyl COFCO 10 OMe Stsiin TOO R 0 624 DSO eo 0 634 eey OOOO OOS In this case there are three processes in one family The ps process PPID 589 has a bash shell as its parent PID 589 Likewise the parent of the bash shell is the login command Process Groups For complex programs with many processes Linux can organize processes into process groups The ps lfw options long full wide will show the PID the PPID and a simulated graph of groups of related processes S ps lfw E UID PADAR P RID TEIR EEN VSZ RSS WCHAN STAT TTY TIME COMMAND 100 0 579 1 0 0 2196 1148 wait4 S EV ESSI OLEI o r1 root 100 0 5189 Suo 0 1828 1060 wait4 S EXC 0 00 bash 100 0 689 55
421. ssages to standard error begin Put Line New Line Text IO defines a This is an example of writing error messages to stderr that you can write error messages to file called Standard Error always open file G Linux http www vaxxine com pegasoft people html book 13 html 11 of 15 7 20 2001 11 35 52 AM Big Online Book of Linux Ada Programming 13 Linux Introduction Put_Line Standard_Error This message is on standard error Put_Line This message is on standard output New_Line you can use Set Output to send all Put Line s to Standard Error Set Output Standard Error Pur rine mhis as also on Standard error Set Outp t Standard Output Put Line But this is on standard output end stderr This is an example of writing error messages to stderr This message is on standard error This message is on standard output This is also on standard error But this is on standard output Everything looks normal until you redirect the output of the program This is the result when the standard output is redirected to a file called out txt The error messages aren t redirected root armitage trials stderr gt out txt This message is on standard error This is also on standard error 13 7 Linux Binary Formats Many people do not think of binary files as having a format because they contain machin
422. stantiate for a particular floating point type For example to set up the package for a custom floating point type called percent with Ada Numerics Generic Elementary Functions type percent is new float range 0 0 1 0 package percentMath is new Ada Numerics Generic Elementary Functions percent use percentMath The use percentMath statement saves us from typing percentMath before every function we use With percentMath instantiated we can now perform basic floating point math functions such as Put_Line 20 to the power of 3 is amp percent image 0 2 3 0 y As shown in the table at the start of this section elementary function packages for the basic floating point types are included with Gnat The elementary package includes Sqrt x SquareRot S Log x Natural Logarithm 1n in some other language Log x b Logarithmtobasesb Exp x RaieebypoweX M f Poweroperator 00000 Sin x c Sine for x where cycle range isc eg 360 for degree Gos x c Cosine for x where cycle rangeise n Tan x Tangentforxradians 000000 Tan x c Tangent for x where cycle rangeisce There are corresponding functions for arctan arccot sinh cosh tanh coth arccosh arctanh artcoth Here s an example using the built in functions for the float type and creating our own functions for our own percent type with Ada Text
423. subtree has an alias to it Is Root True if the tree 1s at the root of tree Item At Return the item at the root of the tree In addition the tree may have an in order pre order or post order generic procedure This procedure traverses the tree and file G Linux http www vaxxine com pegasoft people html book 18 html 18 of 26 7 20 2001 11 38 18 AM Big Online Book of Linux Ada Programming 18 Data Structures executes processes each item Pre_order processes an item before its children Post_order processes an item after its children In_order processes a node in the sort order of the tree after all the left children but before all the right with BC Containers Trees Binary In_Order with BC Containers Trees Binary Pre_Order with BC Containers Trees Binary Post_Order with Global_Heap package shipment_binary is grandfather would be proud type aQuantity is Unknown Basket 6Quart Basket llQuart Bushel Skid Boxcar type aFruit is Apples Grapes Peaches Cherries Pears Plums Other type aShipment is record number Positive number of containers quantity aQuantity the containers contents aFruit ype or Cruit end record procedure visitShipment s aShipment OK out boolean our tree traversal function package shipmentContainers is new BC Containers item gt aShipment Sei ruit container package shipmentTrees is
424. t Ada provides two ways for a thread to communicate with the rest of the program The first communication method is called a rendezvous One task communicates with another by sending a request A task may send a request to another task to update a certain variable or to perform a certain action that would otherwise risk data corruption Because this communication happens on the fly it s declared in two parts First in the task specification a list of all requests the task is prepared to accept These are called entry statements and look much like procedure declarations Suppose we write a task to keep a running total to be shared between several other tasks We use a separate task to keep the total from being corrupted task CountingTask is entry add amount integer end CountingTask In the task body a task indicates when it s ready to accept messages using the accept statement This statement checks for outstanding requests from the rest of the program task body CountingTask is runningTotal integer 0 begin loop accept add amount integer do runningTotal runningTotal amount end add end loop end CountingTask When this thread runs accept statement will check for an add request If there are no outstanding add requests the thread suspends itself until a request is sent waiting indefinitely for a new request Suspending for a request is known as blocking An accept statement with do part will c
425. t 8 Debugging Your Project lt Last Chapter Table of Contents Next Chapter gt 8 1 Limit and the Heap Size The default storage pool or the heap is kept on the user s stack Unusually large variables in subprograms including the main program can cause out of memory errors Variables in packages are not affected by the stack size You can increase the stack space using Linux s limit command although using dynamic allocation is usually a better solution limit stacksize 1024 kbytes 1 Megabyte user stack To constrain the size of your stack as far as Gnat is concerned use the GNAT_STACK_LIMIT environment variable to indicate the number of kilobytes of stack space In individual Ada tasks the stack size can be set by pragma Storage_Size Stack size checking is normally disabled by Gnat Section 4 4 discusses this 8 2 The Debugging Pragmas Ada Feature Description C Equivalent pragma Assert condition Assert a condition assert pragma Debug Procedure Debugging procedure call pragma Suppress Debug Info Disable pragma debug fifdef var endif ens a subprogram that pragma No Return subprogram never completes a eee Ped scalars to illegal _ values GNAT provides two useful pragma for debugging programs To use these pragmas you need to use the gnata option during compiling Removing gnata causes GNAT to ignore these pragmas making it easy to compile
426. t c 5 Put Line The character you typed was amp c amp end basicio This program displays information on the screen and reads information from the keyboard file G Linux http www vaxxine com pegasoft people html book 10 html 3 of 29 7 20 2001 11 33 05 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada Put_Line displays a line of text and advances to the next line Put displays text but it doesn t start a new line New_Line displays a blank line Get waits for a character to be typed Type a key and the Enter key to continue C The character you typed was c Besides letters and numbers there are special characters called control characters which instead of displaying a character change the Linux display To print controls characters you need to use one of Ada s built in character sets For example ASCII is a predefined list of all the ASCII characters To send an explicit form feed character use Put TENSILE Sm 9 Some common control characters are ASCII NUL C end of string character ASCII CR carriage return move to beginning of line ASCII HT horizontal tab ASCII LF line feed start a new line ASCII FF form feed start a new page on a printer C Put doesn t recognize C string escape codes like n or r Besides ASCII Ada has a number of other character sets defined in the Ada Characters packages The ASCII set is officially made obs
427. t Vertex move an arch s first item to a new item e Set Second Vertex move an arc s second item to a new item e First Vertex return the first item for an arc e Second Vertex return the second item for an arc There are two iterators a graph iterator and an item iterator Graphs should not be Guarded 18 1 17 Smart Pointers Smart pointers are an access type that counts the number of references to the item being pointed to Your program allocates the item The item is deallocated when no more pointers point to it Smart pointers are a simplified form of garbage collection The smart package provides the following subprograms e Create create a new smart pointer from an access variable e Value return the item pointed to by the smart pointer with BC smart package depts is type departments is accounting information technology type deptAccess is access all departments package deptPtrs is new BC smart departments deptAccess end depts with ada text io depts use ada text io depts procedure sp demo is shipping human resources accountingPtr deptPtra Pointer accounting Ptr deptPtrs Pointer department deptAccess begin Put_Line This is a demo of the Booch components smart pointers New_Line department new departments accounting file G Linux http www vaxxine com pegasoft people html book 18 html 24 of 26 7 20 2001 11 38 18 AM Big
428. t _Line In binary Chis is SES Ec DOTT GIRO Put_Line Shifted left once is amp Shiite Lefi six 1 OL Palme QE Put_Line Shifted left twice is amp Shift _Left six 2 img PE Put_Line Shifted right once is amp Shife RINE Six Imo E Put_Line Arithmetic Shifted right once is amp Shift Right Arithmetic six 1 J img J end shiftMath Time to do a little bit shifting Our integer is 6 m pinary chis is e Shifted left once is 12 Shifted left twice is 24 Shifted right once is 3 Arithmetic shifted right once is 3 12 15 Exception Handling and Traceback Packages Gnat includes packages for working with exceptions Using these packages you can add a message to your exceptions save exceptions and examine an exception occurences when they are raised Traceback is a technique to examine the run time stack and identify where an exception occurred Gnat can identify the specific source file and line where an exception occurred To use tracebacks in Linux you must compile your program with the funwind tables switch and bind with the E switch Zero cost exceptions not covered yet KB with Ada Text IO Ada Exceptions Gnat Current Exception Gnat Traceback Symbolic use Ada Text IO Ada Exceptions Gnat Current Exception Gnat Traceback Symbolic file G Linux http www vaxxine com pegasoft people html book 12 html 32
429. t in first out list ues ordered bounded tainers queues ordered dynamic tainers queues ordered unbounded A sorted list items removed from the front tainers rings bounded tainers rings dynamic tainers rings unbounded tainers sets bounded bc containers sets dynamic bc containers sets unbounded bc containers stacks bounded Stacks bc containers stacks dynamic bc containers stacks unbounded AVL Trees bc containers trees avl tainers trees binary in order Binary Trees bc containers trees binary post order bc containers trees binary pre order bc containers trees multiway post order bc containers trees multiway pre order Sets Last in first out list A list with two successors per item bc graphs directed bc graphs undirected bc smart A definition of common data structures can be found at the National Institute of Standards and Technology The components are generic packages and must be instantiated for a particular type They are arranged in hierarchies of generic packages Each parent package must be instantiated before its child For example to use single linked lists bc containers lists single bc containers bc containers lists and bc containers lists single must all be be created for the item type As with many component libraries the Booch components represent all structures in memory not in lo
430. t is O for a timeout 1 for failure or the number of file discriptors that are ready and the file discriptor sets indicate which ones Unlike most UNIX s Linux leaves the time remaining in the timeout record so that you can use select in a timing loop to repeatedly select file descriptors until the timeout counts down to zero Other UNIX s leave the timeout unchanged type pollfd is record fd integer events short integer revents short integer end record Poll Events POLLIN 46315 POLLPRI sedg POLLOUT 16744 POLLERR 16 8 POLLHUP 167104 POLLNVAL S Gs DOs 6 These are defined in asm poll h procedure poll result out integer ufds in out pollfd nfds integer timeout milliseconds integer pragma import C poll pragma import valued procedure poll The name of this kernel call is misleading poll is a form of select timeout milliseconds is a timeout in milliseconds 1 for no timeout ufds is an array of pollfd records for files that poll should monitor Poll returns the number of pollfd array elements that have something to report 0 in a timeout or 1 for an error Each bit in events when set indicates a particular event that the program is waiting for Revents represents the events which occurred file G Linux http www vaxxine com pegasoft people html book 16 html 20 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 A
431. t not happier the siring is J Append us but not happier Put Line us New Line Put Line The ampersand will work as well amp us New Line Put Line The fifth character is amp Element us 5 New Line Put Line Replacing the 20th character we get Replace Element us 20 Put Line us New Line Put Line The 5th to 8th charcaters is amp Slice us 5 8 New Line Put hdsne The first occurence of ch is at amp Index us Tehi M Em cn Ne file G Linux http www vaxxine com pegasoft people html book 12 html 3 of 35 7 20 2001 11 34 25 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages New_Line Put Line The first non blank character is at amp Index Non Blank us img New Line Put lane Replacing the first rich with RICH we get Replace olice Us 9r Sy RICHY UE Put_Line us New_Line Put _lLine Insgerting really at the 5th character we get Insert us 5 really t Put_Line us New_Line PUE Line Overwriting characters 5 to 8 we get J Overwrite us 5 most Put Line us 7 New_Line Put tine Deleting characters 5 through 11 we get Delete us 5 11 Put Line us New Line Put Line The first 8 characters at the head of the string are Put Line Head us 8 New Line Put lime The last 8 characters a
432. t of 3 SKID S of PEACHES Shipment of 7 BASKET_11QUART S of PEARS Shipment of 12 BUSHEL S of APPLES Shipment of 5 BASKET_6QUART S of CHERRIES Binary trees should not be Guarded 18 1 14 AVL Trees AVL trees are binary trees that are balanced On every insert or delete the tree is restructured to keep its symmetry As a result the trees must be sorted by the Booch component and the program using the AVL tree must provide a lt function to sort the tree by The AVL package provides fewer subprograms than the binary tree package e Clear destory the AVL tree e Insert add an item into the AVL tree e Delete remove an item form the AVL tree Extent return the number of items in the AVL tree Is Null true if there are no items in the AVL tree Is Member true if an item is in the AVL tree There are no subprograms for walking the tree Here is a sample declaration with BC Containers Trees AVL with Global Heap package fruit avl is more fun with Peuae type aQuantity is Unknown Basket_6Quart type aFruit is Apples Grapes Peaches type aShipment is record Visit traverse the tree in order executing a read only procedure Modify traverse the tree in order executing a procedure that can alter the items Basket_11Quart Bushel Skid Boxcar Cherries number Positive number of containers quantity aQuantity the contai
433. t of file utilities as well as the ability to run blocked and non blocked child processes The price for this low level OS support is the need to use a lot of addresses access and C strings there is also a thin binding available for basic C stream functions described below with text io gnat os lib use text io gnat os lib procedure ostest is fd File Descriptor FilePath constant string testfile xxx amp ASCII NUL for write test FirstLine constant string This is the first line in the file AmountWritten integer for time stamp test iss OS Time Dec 3 Meee IAE Month Month_Type file G Linux http www vaxxine com pegasoft people html book 14 html 1 of 15 7 20 2001 11 36 18 AM Big Online Book of Linux Ada Programming 14 Linux Programming Day t Dicky malin oes Hour E AHON raV Minute Minute Type Second Second Type for location test so String Access bor delete cest WasDeleted boolean for spawn test Arguments Argument List 1 1 Ls constant string bany lsg s WasSpawned boolean Rooubir alased string se 7 begin PuUE lane This ie en exemple or the Goer S OS Library ps New_Line Put_Line Creating a new file fd create_file FilePath address Binary if fd invalid_fd then Put_Line Unable to create amp FilePath else Put Line Created Y e FilePath 5 end if New_Line Put_Line Getting
434. t of the run time begin for i in s range loop put sii j end loop new line end put line begin put line Hello World end nrt 16 17 Linux Sound The Linux sound capabilities called OSS were developed by 4front technologies You can find more advanced documentation at their website http www opensound com This section describes only the basic functions The newest Linux sound standard is ALSA file G Linux http www vaxxine com pegasoft people html book 16 html 31 of 47 7 20 2001 11 37 16 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming Most distributions have OSS in the kernel by default but there s no reason that OSS must be present it can always be turned off for computers without a sound card 16 17 1 Detecting a Sound Card Open the file dev sndstatus If there is no error the computer has a sound card 16 17 2 Playing Sound Samples There are no C libraries or kernel calls to play sound samples Instead there is a device file called dev dsp which plays sound samples in the au sound format The au sound format consists of a header describing the sound followed by the actual sound data The header looks like this type AAUHeader is record Magic integer a unique number denoting a au file as used with the magic file SND MAGIC Hex 646E732E bytes 2E 73 6E 64 dataLocation integer offset or pointer to the s
435. t setting for gcc 2 We followed the instructions in the gcc INSTALL file configure with gnu as with gnu ld enable threads posix host i686 pc linux gnu 3 We checked the gcc makefile to make sure 1686 pc linux gnu was reasonable It required lib6 and lib6 was installed The Makefile also showed that the 1686 setting is compatible with our Pentium 1586 4 Before running make we changed the Makefile s OLDCC variable from cc to usr bin gcc There was a cpp syntax error while building 1ibgcc1 a probably the error the Slackware people encountered We tracked down the line causing the problem in the Makefile and discovered they were calling cc to do the compiling which doesn t handle the C preprocessor cpp properly Typing in the line at the shell prompt showed that usr bin gcc worked fine while usr bin cc would not The note in the Makefile said we shouldn t use gcc to avoid circular references in some of the functions that is that it might inadvertantly call the 2 8 1 compiler instead of the old 2 7 2 3 compiler so we made sure we included the full path 5 make LANGUAGES 2 c c 6 mkdir stagel make stagel make CC stagel xgcc Bstagel CFLAGS g 02 fsigned char 7 mkdir stage2 make stage2 make CC stage2 xgcc Bstage2 CFLAGS g 02 fsigned char 8 make compare reported no errors 9 make install CC stage2 xgcc Bstage2 CFLAGS g 0O2 LANGUAGES c c 10 gcc v and gcc dumpversion reported the c
436. t the tail of the string are 5 Put_iLine Tail us 8 i gt New_Line Count is ambiguous because of the use clauses Put _Line The count ol er is amp Ada Strings Unbounded Count us er img New_Line end strdemo This program shows some Ada string capabilities Our test string is The rich get richer mm To_Unbounded_String converts a string to an unbounded string The rich get richer The length of the string is 19 If we append but not happier the string is The rich get richer but not happier The ampersand will work as well The rich get richer but not happier file G Linux http www vaxxine com pegasoft people html book 12 html 4 of 35 7 20 2001 11 34 25 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages The fifth character is r Replacing the 20th character The The The first occurence of we get rich get aiken but not happier 5th to 8th charcaters is rich Urea The first non blank character is at 1 Ss at 7 vusabieia SHE The RICH ette rout not happier at the 5th Replacing the first rich we get Inserting really character we get The really RI Overwriting characters 5 to 8 y RI CH get richer but The most CH get dehet not happier we get not happier Deleting characters 5 through 11 The The first 8 characters at the head of the string are The RICH The last 8 characters at the
437. tainer_Error exception Duplicate exception Tllegal_Pattern exception Is Null exception Lexical Error exception Math Error exception Not Found exception Not Null exception Not Root exception Overflow exception Range Error exception Storage Error exception Synchronization Error exception Underflow exception Should Have Been Overridden exception Not Yet Implemented exception The data structure components are Data e psc Booch Packages Description Unordered bc containers bags bounded Bags bc containers bags dynamic bc containers bags unbounded collection of items Duplicates are ers collections bounded bc containers collections dynamic bc containers collections unbounded Collections tainers deques bounded bc containers deques dynamic bc containers deques unbounded with a head and a pointer to each successive item bc containers lists single or more items with a head and a pointer to both successive and previous items bc containers lists double file G Linux http www vaxxine com pegasoft people html book 18 html 2 of 26 7 20 2001 11 38 16 AM Big Online Book of Linux Ada Programming 18 Data Structures bc containers maps bounded tainers maps dynamic tainers maps unbounded ues bounded tainers queues dynamic tainers queues unbounded Firs
438. tainers Next i Put_Line Are we done amp customerContainers Is Done i img begin C customerContainers Current item i exception when BC NOT FOUND gt put line BC NOT FOUND exception no item at this position in the list end end list demo mhis acs a The The The The ls aes al lis iles Gh ct uc cl 1 Added cust The list i The lis The lis The hea il 1 O Gl Gk 1g demo of the TH Li s empty TRUI is shared FALSI ength is 0 omer 7456 s empty FALSE is shared FALSI ength is 1 tem is cust The foo i tem is cust Appended Tine Iisi The head mhe fooi al ab i ustomer 9362 ength is 2 tem Resetting The curren Are we don Advancing The curren Are we don Advancing Are we don BC NOT FOU Booch components Lomer comer tem is customer is customer single linked lists is newly declared CI h Li Lr id id 7456 7456 id rd 7456 9362 the iterator t item is cust e FALSI to the next i t item is cus e FALSI to the next i e TRUE ND exception h Li h Li Li tomer id 7456 tem tomer id 9362 CEM no item at this position in the list Single linked lists should not be Guarded 18 1 4 Double linked Lists Double linked lists are implemented exactly the same as single linked lists except that the word Dou
439. tatement loop Loops are exited with an exit statement Ada provides a shorthand exit when to exit on a condition loop X X 2 5 exit when X 4 0 D X 1 0 end loop c There is no general purpose loop in C file G Linux http www vaxxine com pegasoft people html book 10 html 27 of 29 7 20 2001 11 33 08 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada C There s no equivalent of the C continue statement There is a pretest loop while which determines whether or not the loop should be entered or reentered based on an expression at the top of the loop while X gt 4 0 loop Xe 7 25 Trt 10 end loop C This is the equivalent of a C while loop There is no post test loop like C s do loop There is the standard for loop as well to loop through a range of numbers For loops in Ada may only loop by discrete numbers one unit at a time no real numbers and no arbitrary stepping values To go backwards through a range use the word reverse for I in 1 10 loop Total Total die end loop To loop through an entire range of a type use the range attribute To loop through all the dogs in an enumerated type called aDogBreed for dog in aDogBreed range loop Also note that dog is implicitly defined You don t have to declare it Ada understands the type from the loop and the loop variable exists for the duration of the loop C For is much more structured than C s for Any l
440. tedly Warnings umcompilrwamingsonorofff Weak External specify an identifier that doesn t have to beresolved bythelinker GNAT specific The use of these pragmas are covered in detail in the GNAT and Ada 95 reference manuals 11 14 Low Level Ada Ada Description ic Equivalent file G Linux http www vaxxine com pegasoft people html book 11 html 37 of 39 7 20 2001 11 33 48 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming iable is infl i f pragma volatile pne meee dee volatile declaration program if 1 f for x address use a dc p adien tota p typecast integer pointer Position the i Tm for aiadqumene case Ub osition t e identifier x on b byte 9 boundaries for x bit order use o Store record using bit order o 8 value Specify a octal numeric literal OValue eee specify a hexadecimal numeric TIS literal asm inst in out Assemble an instruction asm anse 8 aliny ES OUE Ada contains a number of low level features and libraries such as the ability to add machine code to a program or to access a hardware register in memory I ll mention a few of these features here If you need to specify a specific number of bits say to access a hardware register use the for statement type Reg is new integer for Reg size use 4 register is 4 bits type RegPtr is access all Reg You can refer an access type to a parti
441. teger array is a C integer array e in parameters are the same as pass by copy parameters in C e in out parameters are the same as passing a pointer as a parameter in C e Ada string parameters ending in ASCII NUL are the same as a C string e Ada procedures are the same as C void functions There are rare cases when these assumptions don t hold e g certain cases when null pointer parameters are not allowed by Ada but generally speaking these assumptions are valid under Linux Gnat has general purpose interfacing pragmas and support for C types in the Interfaces C package Use these if you want maximum portability Because of these assumptions most C library calls are easily represented in Ada For example we check the man page for gettime and discover it returns the current time as a long integer To call this from Ada we use function gettime return long integer pragma Import C gettime Since there is no Ada body for the gettime function we use pragma import to let gnat know gettime is a C function When we link we need to specify the C library that function is in In the case for the GNU C library this is unnecessary since it s automatically linked We can now call the C function gettime as if we wrote it ourselves In C it s possible to call a function and discard the result by not assigning it to anything You can call C functions from Ada this way by declaring them a procedure For example procedure gettime pragma Import C
442. tem s features without changing the original item LRM is the abbreviated name of the Language Reference Manual sometimes called Ada Reference Manual LRM was often used in the days of Ada 83 RM or rm95 Multiple Inheritance Creating new items from two or more original item s features without changing the original item Polymorphism A means of factoring out differences amongst a collection of items so that programs may be written in terms of the common features RM see LRM RM95 see LRM Static Polymorphism Polymorphism implemented at compile time generics lt Appendix F Table of Contents End of Book file G Linux http www vaxxine com pegasoft people html book 99_z html 7 20 2001 11 41 10 AM
443. ternal generaic package Decimal Output must be instantiated for a particular numeric type Only decimal types are allowed type money is delta 0 01 digits 18 package formatted io is new ada text io editing decimal output money To Picture converts a string to a picture type Pic String returns the string of the picture type p picture To Picture 4449 99 S a Sering Pic Tring p T Valid returns true if a string is a valid picture When Blank_When_Zero parameter is true a zero represented as an empty string is allowed By default the picture string must show something for a zero Blank_When_Zero can also be used with To_Picture if not Valid 9 99 then P t Lines Standard Error This is a bad picture string J end if Put displays the formatted decimal value There is also an Image function that returns the results as a string instead of displaying it on the screen Length returns the length of the formatted output There is no Put_Line file G Linux http www vaxxine com pegasoft people html book 12 html 15 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages pute 455 327 pic J str Image 455 32 pic P t scr 4555382 Pie Here is an larger example with ada text_io editing use ada text_io use ada text_io editing procedure formatted is type money is delta 0 001 digits 18 package formatted_io is new ada text_io editing decimal_output money
444. th NULL else if param2 0 O execlp path path paraml NULL else if param3 0 0O file G Linux http www vaxxine com pegasoft people html book 13 html 5 of 15 7 20 2001 11 35 51 AM Big Online Book of Linux Ada Programming 13 Linux Introduction execlp path path paraml param2 NULL else execlp path path paraml param2 param3 NULL if we got here file probably wasn t found exit errno wait amp status if WIFEXITED status 0 status WEXITSTATUS status return status It is possible to rewrite this subprogram into Ada but it s easier in C because of the constants macros and execlp takes a variable number of parameters This function returns some special exit status values 110 if dev null couldn t be opened for standard input and 111 if the output file you specified couldn t be opened function CRunIt cmd outfile parml parm2 parm3 string return integer pragma Import C CrunIt CRunIt Result CrunIt bin ls amp ASCII NUL executable to run emp Isr us e ASCII NUL where output should go amp ASCII NUL parameter 1 none amp ASCII NUL parameter 2 none amp ASCII NUL parameter 3 none An important part of running commands like this is deciding on temp file names that won t be used if two copies of the program are run at th
445. th Global_Heap package fruit_sets is my grandfather owned one of the largest fruit companies in type aFruit is Apples Grapes Peaches Cherries Pears function FruitHash f aFruit return Positive our hash function for the set package fruitContainers is new BC Containers item aFruit asic fruit container package fruitSets is new fruitContainers Sets basic set support package fruitBoundedSets is new fruitSets Bounded fruitHash Buckets gt 10 Size gt 20 our actual set is an unbounded set end fruit_sets the world Plums Other i package body fruit_sets is function FruitHash f aFruit return Positive is begin return aFruit pos f 1 good enough for this example end FruitHash end fruit_sets file G Linux http www vaxxine com pegasoft people html book 18 html 11 of 26 7 20 2001 11 38 17 AM Big Online Book of Linux Ada Programming 18 Data Structures with ada text_io kb_sets use ada text_io kb_sets procedure set_demo is Use ELUATE SeES use fruitBoundedSets sl Bounded_Set S2 Boundeduser S9 Bonded Ser begin Put_Line This is a demo of the Booch components sets New_Line sl apples sl peaches Add s2 apples Add s2 peaches Add s2 pears Put_Line Set 1 has
446. th a leading message to standard error function strerror error number integer return strptr pragma import C strerror Retuns a C string standard error description The following example program makes a deliberate error with the link function and prints the error message using perror and stderror file G Linux http www vaxxine com pegasoft people html book 16 html 3 of 47 7 20 2001 11 37 13 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming with ada text_io ada strings fixed use ada text_io ada strings fixed procedure perr is an example of perror and strerror error messages procedure perror message string pragma import C perror print a standard error description with a leading message type string255 is new string 1 255 type strptr is access string255 error messages are no longer than 255 characters function strerror error number integer return strptr pragma import C strerror get a standard error description errno integer pragma import C errno last error number function link pathl path2 string return integer pragma import C link we ll use the link function to create an error LinkResult integer value returned by link TIGIeO iMAC Iie B Cetero Ede pointer to stderror message NullLocation integer location of NUL in stderror message begin Put Line Thi
447. th system with unchecked conversion procedure pointers is package intptrs is subtype object is integer file G Linux http www vaxxine com pegasoft people html book 8 html 3 of 6 7 20 2001 11 32 24 AM Big Online Book of Linux Ada Programming 8 Debugging Your Project package address_to_access_conversions renames intptrs mak IL type object_pointer is access all object for object_pointer size use 32 function to_pointer value address return object_pointer function to_address value object_pointer return address pragma convention intrinsic to_pointer pragma convention intrinsic to address freeze object pointer freeze to pointer freeze to address end intptrs package body intptrs is function to address value object pointer return address is begin if value null then return null_address else re t rn valu ue allladdress end if end to_address function to_pointer value address return object_pointer is package a_to_pGP3183 is subtype source is address subtype target is object_pointer function a to pR s source return target end a to pGP3l535 function a to p is new unchecked conversion address object pointer begin return target source value end to_pointer end intptrs package intptrs is new system address_to_access_conversions integer five aliased integer 5 int pornter iDtptrs object pointer null int address system address
448. the project and create a working executable file People To be finished 3 1 8 The Menu This is the About window It shows information about the current version of TIA including the version and copyright notice 3 2 GRASP The X Windows IDE GRASP is a free X Windows IDE that supports Ada 95 It s based on Motif and provides similar basic features to TIA The main difference is that GRASP is a multi language IDE and that it supports source code analysis annotating your source code with Control Structure Diagrams CSD s and showing code complexity with graphs called CGP s file G Linux http www vaxxine com pegasoft people html book 3 html 5 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s GRASP v6 3 E GRASP CSD Ada95 home den pegasall_sources tia printer_ adb 1 with Ada Text IO System tiacommon os 2 ise Ada Text IO tiacommon os 3 pragma optimize space body printer is i GRASP CPG Ada95 home dan pegasoft sources tia printer 5 type AStdioFileID is f P function popen comm 7 pragma import C popen p em procedure pclose re 9 pragma import C pclos 12 pragma import C fputc 10 pragma import valued pr C T Complexity 7 11 Ei function fputc c p Totals e x i t Complexity 81 050407 Besides Ada 95 GRASP supports C C Java and VHML source files It supp
449. the range of possible values for the type peopleHeight This is the same as using array peopleHeight range You can create a multidimensional array by using more than one index to the table type peopleStats is array peopleHeight peopleAge of integer You can assign default values to an array using the assignment operator The list of values is enclosed in brackets You can specify a specific value using gt or specify a default with others gt PeopleHeightsl peopleHeightList others gt 0 looks strange but assigns 0 to all the heights in the entire list peopleHeights2 peopleheightList 10 others gt O0 first height is 10 others are 0 peopleHeights3 peopleHeightList 5 gt 15 others gt O0 fifth height is 15 others are 0 Arrays are accessed by specifying values for the indices To get the height for the fifth element in the PeopleHeights1 array you d type Put_Line PeopleHeights1 5 img Records are collections of related information Each subsection is referred to as a field type employeeProfile is record name Seeing 1 320 salary aSalary age einage end record You can assign default values to the fields in a record using the assignment operator type employeeProfile isrecord name string 1 80 others gt salary asalary Sm age anAge 30 end record Default values for whole records c
450. the repository and a subdirectory called CVSROOT Then you define an environment variable called CVSROOT so CVS knows where to find the CVS directory For example to make home our project cvs the repository for your team set up the CVSROOT under bash as export CVSROOT home our project cvs Ihe repository holds copies of all the files change logs and other shared resources for your project To add a new project to the CVS repository use the import command Import will take the files in the current directory and put them in the repository under the name you specify Import also requires a short string to identify who is adding the project and a string to describe the state of the project This strings are comments and can be anything your login and inic rel for initial release may be good choices By convention CVS begins numbering your project with 1 1 roct redbase cvs cvs import project kburtch init rel CVS starts your default editor typically vi NISI CVS Enter Log Lines beginning with CVS are removed automatically file G Linux http www vaxxine com pegasoft people html book 9 html 3 of 6 7 20 2001 11 32 37 AM Big Online Book of Linux Ada Programming 9 Team Development CVS CyS make notes and exit vi N project currency adb No conflicts created by this import The N project currency adb line indicates that CVS created a new project called project and add
451. tiinau Ada Text_IO Integer_Aux Internal Use a tiinio Ada Text_IO Integer_IO Internal Use a timoau Ada Text IO Modular Aux Internal Use a timoio Ada Text_IO Modular_IO Internal Use a tiocst Ada Text_IO C_Streams Mos for reading writing C text files a titest Ada Text IO Text Streams Text Text IO stream definition stream definition a unccon Ada Unchecked Conversion Standard Ada unchecked Seien 8 subprogram a uncdea Ada Unchecked Deallocation Standard Ada unchecked deallocation subprogram b viti Ada Wide Text 10 Een PE caer wide characters file G Linux http www vaxxine com pegasoft people html book 99_f html 5 of 9 7 20 2001 11 40 56 AM Big Online Book of Linux Ada Programming Appendix F Basic Text_IO package for a Wtcoau Ada Wide Text IO Complex Aux long long float complex numbers a wtcoio Ada Wide Text IO Complex IO Generic Wide Text IO package for complex numbers Wide Text IO package for a Wtcstr Ada Wide Text IO C Streams reading writing wide C text files la wtdeau Ada Wide_Text_IO Decimal_Aux Internal Use la wtdeio Ada Wide_Text_IO Decimal_IO Internal Use aeda ida Wide Text OE de cde a wtenau Ada Wide Text IO Enumeration Aux Internal Use a wtenio Ada Wide Text IO Enumeration IO Internal Use a wtfiio Ada Wide_Text_IO Fixed_IO Internal Use a wtflau Ada Wide Text IO Float Aux Internal Use a wtflio Ada Wide Text IO Float IO Internal Use a
452. tion of how Ada 95 rounds New_Line ShowRounding 253 0 ShowRounding 253 2 ShowRounding 253 5 ShowRounding 253 8 ShowRounding 253 8 e end rounding This is a demonstration of how Ada 95 rounds SPORET icelacks ice 253 5928 02 iene Tce 253 SPSE rounds ico 24 53 9eitr 02 rounds co 254 POO CH Os rounds EO 254 Float number Float number Float number Float number Float number NO MN DN LN You can compare the results with the following C program include lt stdio h gt static void show_rounding float f int i i f prine El oat n mber s9 E prumtr rounds co sawn a s file G Linux http www vaxxine com pegasoft people html book 10 html 6 of 29 7 20 2001 11 33 05 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada show rounding int main show rounding 253 0 show rounding 253 2 show rounding 253 5 show rounding 253 8 return 0 Hide number 253 rounds to 25S Izd excu number 259 2 rounds to 253 Eloat number 2529 5 rounds to 253 Float number 253 8 rounds to 253 Rounding to integers is a common way in C business applications to round money to the nearest dollar or cent This is accomplished by multiplying the floating point value by 100 0 adding 5 and then taking the integer value and converting it once more into a floating point value In Ada there s a built in type attr
453. tion on the screen and reads information from the keyboard Put_Line displays a line of text and advances to the next line Put displays text but it doesn t start a new line file G Linux http www vaxxine com pegasoft people html book 12 html 6 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages New_Line displays a blank line Get waits for a character to be typed Type a key and the Enter key to continue g The character you typed was g Not complete These packages are only useful for simple programs Usually you will rely on packages libraries provided for your project Text IO file operations are very limited and are only intended for quick and dirty programs There are other libraries for more extensive file operations such as Ada Sequential IO and Ada Direct IO There is also a subpackage for displaying formatted text such as columns of numbers 12 2 210 Aux GNAT s IO Aux package provides three commonly used functions to Text IO programs testing for a file s existence and reading an unlimited length strings from a text file or a console with Ada Text IO GNAT IO Aux use Ada Text IO GNAT IO Aux procedure ioaux is this program demonstrates the features of the IO Aux package TestFile string etc passwd procedure ScanString s string is begin Put Line The string you typed was amp s Put Line It is amp s
454. tion table Debug jpecifyadebuggingprocedure call Discard Names discard ASCII representation of identifiers as used by img Elaborate elaborate a certain package before thisone Elaborate_All elaborate all with ed packages before thisone Elaborate Body elaborate a package s body immediate after it s spec Eliminate indicate an identifier that is not used in a program created by gnatelim Error Monitoring treat errors as warnings during acompile Export export an identifier from your program so it can be used by other languages Export Function export an Ada function with additional information over pragma Export file G Linux http www vaxxine com pegasoft people html book 11 html 35 of 39 7 20 2001 11 33 48 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Epai Obed EUR n Ada tagged record with additional information over pragma Export Procedure export an Ada procedure with additional information over pragma Export Export Valued Procedure ee En Ada side effect function with additional information over pragma Extend Sysem jobsodet Finalize Storage Only no finalize on library level objects primarily for gnat s internal use ident object file identification string no effect with Linux Import importan identifer from another language so it can be used in your program import Function
455. tions Sin 45 360 is neither pure nor preelaborate because a function must be called when the package is initialized In these cases you can tell Ada specifically which package should be elaborated first Pragma Elaborate package tells Ada the specified package should be elaborated first For example all generics must be elaborated before they are used so it s a good idea to use pragma elaborate on every generic package with generic_linked_list pragma Elaborate generic linked list Pragma Elaborate All indicates that a particular package and all the packages used by that package must be elaborate before the current package For example if package userio uses package common with userio pragma Elaborate All userio will elaborate both userio and common prior to this package Because Elaborate All will affect multiple packages it can cause unnecessary binding errors when used indiscriminately This pragma when used everywhere effectively requires all packages to be arranged in a strict hierarchy Make sure this is the effect you want 11 2 3 Other Elaboration Pragmas Another pragma pragma Elaborate Body forces the package body to be elaborated before the package specification This is especially useful in generic packages Pragma Elaborate and Elaborate All can also be used to resolve ambiguous elaborations 11 3 Objects Ada Description C Equivalent type tagged record Define an object class os ith
456. to create a new one delete the original and copy the new one in place of the original There are several useful functions for direct IO files e Is Open is true if the file has been opened End Of File is true if you have read the last record in the file This is unavailable in out mode Name is the path of the file Mode is the current file mode Size is the number of rows in the file e Indexisthe number of the current row The following example program reads and writes customer information using the Ada Direct IO package file G Linux http www vaxxine com pegasoft people html book 12 html 11 of 35 7 20 2001 11 34 26 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages with Ada Text IO Ada Direct IO Ada IO Exceptions use Ada Text IO procedure dirio is Ada Direct IO example type aCustomer is record name S Sic aeabiate t ie 40 amountOwing float end record a customer record with two fields package aCustomerFile is new Ada Direct_IO aCustomer use aCustomerFile instantiate a new package for direct IO on a file of Clstomen records CustomerFile aCustomerFile File Type our customer file use aCustomerFile because Text IO and Direct IO have File Type cr aCustomer begin Put Line This is a Ada Direct IO example New Line create the fil Create CustomerFile Mode Out File Name gt customer dir displ
457. tract Red and Write subprograms to add and remove data from the stream The following is an in memory stream creating by Warren Gay This stream can share data between programs buffering the data as text in memory If a buffer overflow occurs an END ERROR is raised Id memory stream ads v 1 1 2000 11 26 05 00 18 wwg Exp c Warren W Gay VE3WWG ve3wwg home com ve3wwg yahoo com Protected under the GNU GPL License with Ada Finalization Ada Streams use Ada Finalization Ada Streams package Memory Stream is type Stream Access is access all Ada Streams Root Stream Type Class type Memory Buffer Max Elem Stream Element Offset is new Controlled with private file G Linux http www vaxxine com pegasoft people html book 11 html 29 of 39 7 20 2001 11 33 47 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming object The new Stream Type Root_Stream_Type NOT derived from Controlled No which must be derived from te that Root_Stream_Type is E SO 1f controlled attributes are necessary be defined separately as is done with Memory_Bu th and embedded int feer N ere ey mst t Miks type Memory_Bu lt fer Stream Max_ Root_Stream_Type Mem BU end record type Memory with record Buffer Stream Pl Teeme The overloaded abstr The overloaded a
458. trol The following controls can be used in a TextTools window Thermometer This is a thermometer bar graph It shows the percentage between the maximum value and the current value and is filled based on the percentage ScrollBar This is a scroll bar A thumb is drawn at the relative location of the thumb value to the maximum value of the bar The bar will be horizontal or vertical depending on the shape specified in the Init procedure StaticLine file G Linux http www vaxxine com pegasoft people html book 15 html 7 of 13 7 20 2001 11 36 37 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings This is an unchanging line of text EditLine and family This is an editable line of text AdvanceMode if set the cursor will move to the next control when the edit field is full This is useful in business applications where fixed length product numbers are typed in BlindMode if set hides the characters typed This is useful for typing in passwords SimpleButton This is a button that when selected terminates the dialog Instant if set the button acts like a menu item Pressing the hot key will immediately select the button and terminate the dialog Otherwise pressing the hot key only moves the cursor to the button CheckBox A check box is an option which may be turned on or off RadioButton A radio button is one of a set of options which may be turned on or off Every radio button has a family number
459. ttons and returns the number of the button selected Plays an optional sound Example NoteAlert The database has been updated file G Linux http www vaxxine com pegasoft people html book 15 html 6 of 13 7 20 2001 11 36 37 AM Big Online Book of Linux Ada Programming 15 Free Ada Bindings 15 2 7 Other Predefined Windows SelectOpenFile displays a dialog for opening files It has parameter ASelectOpenFileRec You have to fill in certain before displaying this window SelectSaveFile displays a dialog for saving files It has one parameter ASelectSaveFileRec You have to fill in certain details before displaying this window ShowListInfo displays a Str255List list in a window EditListInfo displays a Str255List list in a window and let s the user edit the list Example Sof ASelectOpenFileRec To255 Select a file to open Sok direct false can t select directories SOf Prompt SelectOpenFile sof if sof replied then FilePath sof path amp amp sof fname else user cancelled end if Control Overview Every control must be initialized with the nit procedure Init positions the control in the window and assigns a hot key a short cut key for moving to the control You can turn a control off make it unselectable using SetStatus Setting the control s status to Standby will make it selectable Some controls are automatically turned off such as the static line con
460. typed into a program is known as literals Ada has several kinds of literals e c is a character Character literals are enclosed in single quotes e 5 is an integer e 45 5 is a float or a fixed with one decimal place e This is a string is a fixed string Strings literals are enclosed in double quotes C Ada doesn t have long numerical literals like 45L Numeric literals are a special type called universal integer and adapt to fit the requirements of an expression C Ada strings do not end with an ASCII 0 character they end with the upper bound of the array that encloses them To change an Ada string into a C string concatenate a null character like this Ihas n8 my trang amp ASCII NUL There are three kinds of real numbers A fixed or fixed point number is a number that has a fixed number of decimal points For example U S dollars are often represented using fixed numbers because there are two decimal places A float or floating point number is a number that doesn t have a fixed number of decimal places Decimal numbers are a variation of fixed numbers commonly used for currency Some Ada programmers recommend that floats are used whenever possible because float calculations are usually faster than fixed calculations This is because most computers today have floating point support in their hardware Floating point numbers are very important for business and scientific applications When floating point numbers are
461. ual pages 13 5 The Linux Kernel There are three basic ways to work with the Linux kernel kernel calls devices and the proc file system Because Linux is organized around files the last two ways let you operate devices and get system information simply by opening and working with files using standard Linux file operations This is makes it easier to work with Linux but it also can make some tasks hard to visualize because you have to do them through a sequence of abstract file operations In a few cases standard libraries and kernel calls have names that overlap which can be confusing In addition Linux sometimes provides alternative versions of system calls based on different flavours of UNIX For example there are two different system calls to assign an environment variable one based on BSD UNIX setenv and another based on the POSIX standard putenv Both do exactly the same thing but their parameters are slightly different Linux provides both to make it easier to move programs written for other versions of UNIX to Linux But for the Ada programmer you have to choose the one that s easiest to use in your program 13 5 1 Kernel Calls Kernel calls sometimes called system calls or syscalls are basic operations that are implemented directly in the kernel There are C libraries which supply some thin wrappers on the calls which do some of the setup and cleanup for your Most kernel calls are in described in the C header file unistd h
462. uccess ftime is an obsolete version of this function file G Linux http www vaxxine com pegasoft people html book 16 html 5 of 47 7 20 2001 11 37 13 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming procedure settimeofday result out integer tv in out timeval tz in out timezone pragma import C settimeofday pragma import_valued_procedure settimeofday Set the current time as the number of microseconds since January 1 1970 Returns 0 for success procedure tzset pragma import C tzset Create the TZ environment variable if it doesn t exist and sets it to the current timezone as specified in etc localtime or usr lib zoneinfo localtime This is automatically invoked by the standard C library time functions whenever necessary procedure adjtimex result out integer buf inout timex pragma import C adjtimex Tunes the kernel s clock for specific time parameters 16 3 3 Functions using the tm record Besides the number of seconds elapsed since 1970 Linux can also work with records containing the time broken down into common measurements These functions use a tm record These functions are all a part of the standard C library type tm is record sec integer seconds on the clock 0 59 min integer minutes on the clock 0 59 hour integer hour on the clock 0 29 mday integer day of the month 1
463. ure wait pid out pid t status in out integer pragma import C wait pragma import valued procedure wait Wait until a child process have finished running Pid is the PID of the child status is an integer code indicating whether the child finished normally and if it was stopped by a signal which signal terminated the program Status can be a null pointer if you don t want status information Example wait wait pid wait status procedure waitpid pid out pid t pid or gid in out pid t status in out integer options integer pragma import C waitpid pragma import valued procedure waitpid Wait for a specific child If pid or gid is less than 1 waitpid waits for any child in the specified group id If pid or gid is 1 file G Linux http www vaxxine com pegasoft people html book 16 html 9 of 47 7 20 2001 11 37 14 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming it waits for any child the same as wait If pid_or_gid is 0 it waits for any child in the same group id as the parent If pid or gid is greater than zero waits for the child with the specified pid Status can be a null pointer if you don t want status information Options can determine whether waitpid returns immediately or blocks indefintely Example waitpid child pid children gid wait status 0 Wait3 and Wait4 are BSD UNIX variations which perform the same functions as wait and waitpid but
464. urn integer pragma import C stat Get information about a file such as size and when it was last opened function lstat filename stringPtr buf stat struct return integer pragma import C lstat Same as stat function but doesn t follow symbolic links function tmpnam s stringPtr return stringPtr pragma import C tmpnam Create a random name for a temporary file function chown path string owner uid t group gid t return integer pragma import C chown function fchown file file id owner uid t group gid t return integer pragma import C fchown Change the ownership of a file to the specified owner and group Example Result chown root txt amp ASCII NUL 0 0 function chmod path string mode mode t return integer pragma import C chmod function fchmod file file id mode mode t return integer pragma import C fchmod Change the read write execute permissions on a file Example Result chmod secure txt amp ASCII NUL 8 640 Other low level file operations are all done with the fentl file control function There are three variations to fcntl it may have an operation code an operation code and a long integer argument or an operation code and a locking record argument The operation numbers are defined in usr src linux asm 1386 fnctl h file G Linux http www vaxxine com pegasoft people html book 16 html 12 o
465. ut Formatted output refers to displaying a value based on a template showing in general how the output should look Because the template is a string it s easy to visualize the results This idea is used in languages like COBOL and BASIC with its PRINT USING command The Ada Text_IO Editing provides formatted output The string template is called a picture The picture can contain the following symbols e the number will be printed with a leading or e a negative numbers will be printed with a leading e and gt a negative number will be printed with e CR a negative number will be printed with a leading CR credit e DB a negative number will be printed with a leading DB debit e the currency symbol will be printed or a floating dollar sign if multiple instances e marks the actual position for a decimal point e V marks the assumed position for a decimal point e 9 space for a number with leading zeros e same as except only the leading character is shown e Z space for a numbers with leading blanks e B 0 inserted B is a blank e space for a number with leading asterisks A PICTURE ERROR is raised if there is a mistake in the layout A LAYOUT ERROR is raised if the layout can t be used with a particular value Using a negative number without specifying a format symbol that allows negative numbers causes a LAYOUT ERROR Before using Text IO Editing the in
466. ut_Line The table begins as ShowTable gnat heap sort a Sort n gt it last Move gt Movelntegers access Lt gt ComparelIntegers access sort elements 1 to top of it array New Line Put Line The sorted table is ShowTable end heaptest This is an example of heap sorting an integer table The table begins as this wasn t corrupted before MS Word bug 12 11 Regular Expressions Regular Expressions refers to pattern matching for strings identifying all strings that adhere to a certain pattern For example listing all files that end with ads using the shell command Is ads is an example of a regular expression GNAT has two built in packages for dealing with regular expressions The first called Regexp performs pattern matching using two different standards First it supports standard UNIX shell file globbing expressions as described by man bash Second it supports BNF patterns as described in the Ada Reference Manual Using the package is a two step process First you must compile the expression using the Compile function Then you check for a string that matches the expression using the Match function The following program demonstrates the Regexp package with Ada Text IO GNAT Regexp file G Linux http www vaxxine com pegasoft people html book 12 html 27 of 35 7 20 2001 11 34 28 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages use Ada Text IO
467. value 1 1s ui Pune 1i width gt 5 Put Line wey s New Line Put Line base specifies a number system besides the normal base 10 Put Using binary notation the value i is Put i base gt 2 New Line New Line Put Line Set the variable Default Width or Default Base to avoid using Put Line width gt and base Put The Default Width was Put Default Width New Line Default Width 20 Put The Default Width is now Put Default Width New Line file G Linux http www vaxxine com pegasoft people html book 10 html 10 of 29 7 20 2001 11 33 06 AM Big Online Book of Linux Ada Programming 10 An Introduction to Ada Puc ine Werle i ahs Puti D Pie LIne ei M New_Line end basicio4 This program displays information on the screen and reads information from the keyboard The value iis 5 Type in an integer number 432 The value i is 432 width gt specifies the amount of room to display the number in This can be used to display columns of numbers Using a width of 5 the value i is S12 base gt specifies a number system besides the normal base 10 Using binary notation the value i is 241101100004 Set the variable Default Width or Default Base to avoid using width gt and base gt The Default Width was 11 The Default Width is now 20 The value i is 432 Table
468. values file gives you the following program with text_io use text io procedure preptest is only include the relevant parts for this version S version string lt beta string is the value of the gnatprep variable named translation Slrranmelaevonm s seeing se Noelia file G Linux http www vaxxine com pegasoft people html book 6 html 4 of 14 7 20 2001 11 31 53 AM Big Online Book of Linux Ada Programming 6 Development Utilties begin Put_Line This is the amp s_version amp edition Put_Line This is the amp s_translation amp translation end preptest The Gnatprep command switches are Dsymbol value define values on the command line instead of a prep values file same as D in C For example DMacintosh FALSE b replace gnatprep commands with blank lines instead of c c comment out gnatprep commands instead of b r generate a Source_Reference pragma s print a sorted list of symbols and values u treat undefined symbols as if they were FALSE C There is no gnatprep equivalent of FILE name of current source file or LINE number of current line 6 6 Profiling with Gprof Gprof in the GNU profiler It shows which subprograms in a program are being executed the most You can use this information to find the parts of a program with the greatest need for CPU efficiency and hand optimize those parts accordingly To use Gprof you must rebuild your pro
469. variable to include the object files for every package used by your program To use this make file type make to build your Ada project or make clean to remove any intermediate files produced by the compiler The ALT version of Gnat uses uses the name gnatgcc not gcc for the GCC compiler file G Linux http www vaxxine com pegasoft people html book 5 html 1 of 6 7 20 2001 11 31 40 AM Big Online Book of Linux Ada Programming 5 Building Large Projects Sample Ada makefile Assumes main program is named main adb by Ken O Burtch OBJS main o somepackage o How to compile Ada files E rele mel gee e Ee CURFIXES sd 30 How to link the main program main OBIS gnatbind xi maun alrz gmatlink main ali elesns ie o o s e celdb3b eOe 5 2 Cook A Parallel Make IDE TIA supports cook To use cook select it in the project parameters window cook is a program for building projects Unlike make cook has additional features such as the ability to define true variables and functions and the ability to build a project using multiple machines in parallel This can be a useful tool for large Ada projects cook also comes with a tool to convert Makefiles to cook Howto cook files If you need to install cook there are four basic steps are e configure run GNU configure e make build cook e make sure verify cook by running tests e make install install cook on your computer When
470. vaxxine com pegasoft people html book 12 html 28 of 35 7 20 2001 11 34 28 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages A globbing pattern is a UNIX shell style pattern matching The pattern a matches anything starting with the letter a accounting matches th xpression President doesn t match the expression sundries doesn t match the expression A non globbing pattern is a BNF pattern as used in the Ada Reference Manual For example a a z means characters beginning with a and with any number of letters following accounting matches th xpression sales doesn t match the expression The second Gnat pattern matching package is Regpat which interprets full UNIX V7 regular expressions as defined in the man regexp Linux man page Don t be confused by the naming conventions the Regexp package does not do Linux regular expressions 12 12 Advanced String Processing spitbol style string processing not finished 12 13 GLADE Distributed Processing GLADE is the free distributed processing package for TCP IP and gnat It is distributed separately from the gnat compiler This should not be confused with the GTK s Glade the GUI builder for the Gimp Toolkit widgets which has bindings for Ada http glade pn org GLADE is built into the ALT version of GNAT To install GLADE unpack it and type configure and make install GLADE works on partitions programs designed to run on
471. when a new one is loaded Diff Displays the differences between the current file and when it was last saved using the di command Print Pipes the file with a header to the Ipr command printing it on the default line printer Stats Display information about the current file and memory usage Stub Creates an empty package body for the current file The current file must be a package spec Check Checks the current file for syntax errors Xref Displays a crossreference of all identifiers in the current file Quit Stops the program file G Linux http www vaxxine com pegasoft people html book 3 html 3 of 10 7 20 2001 11 30 22 AM Big Online Book of Linux Ada Programming 3 Introduction to the IDE s 3 1 4 The Edit Menu Cut Deletes the selected text and puts it in the clipboard Same as ctrl x Copy Copies the selected text to the clipboard without deleting it Same as ctrl b Paste Inserts the text on the clipboard Same as ctrl v Append Moves the cursor to the right end of the current line This is useful for adding comments at the ends of lines 3 1 5 The Find Menu Find Replace Find brings up the find dialog to search for text Fill in the top line and select find to find the next occurrence of the text in your document Select backwards to search towards the top of the document instead of towards the bottom Fill in the replace line and select replace to replace the text you are sear
472. wn storage pools you need to extend the Root_Storage_Pool tagged record found in the System Storage_Pools package give example KB 11 10 2 Access Parameters Because pointers are offen passed as parameters Ada provides a special parameter type just for access types access parameters are access types behave the same as an in parameter you cannot assign a new value to the parameter However because it is an access type you can change what the access parameter points to Access parameters offer some advantages over in parameters with an access type e Ada will verify that the parameter isn t null e Access parameters can be used in functions where in out parameters are not allowed e They avoid access type accessibility errors without resorting to unchecked access Access parameters can t be compared or assigned but you can typecast an access parameter into a normal access type and then compare values or assign it with Ada Text IO use Ada Text IO procedure accparm is An example of access parameters Create a customer account record type money is new float type aPercent is new float type aCustomerAccount is record moneyOwing money 0 0 money on the account interest aPercent 0 15 15 interest end record type aCustomerPtr is access all aCustomerAccount procedure chargeInterest cp access aCustomerAccount is update the customer record by charging the interest begin cp mone
473. work A library which is directly linked into a program so that it is added to the executable is called a static library To link ina file G Linux http www vaxxine com pegasoft people html book 13 html 12 of 15 7 20 2001 11 35 52 AM Big Online Book of Linux Ada Programming 13 Linux Introduction static library just include it s name with the gnatlink command or gnatmake on simple projects By default gnat s own libgnat library is always static because of concerns over multithreading For example if you install and compile the official JPEG library sources a static library file is created named libjpeg a To link this library into your program you d include ljpeg when linking Note that you don t use the entire name of the file gnat assumes there is a beginning lib and ending a One use for static libraries is to create a library for others to use As a small example suppose you have a package p and you want to create a static library to link into a program t You have to put the library s object file p o into a static library eg libp a and change p ali to read only so gnat knows there is no object file included with p Then include lp when making or linking armitage home ken ada testi ls p ads pado pali po bre cl armitage home ken ada test ar cr libp a p o armitage home ken ada test rm p o armitage home ken ada test chmod w p ali armitage home ken ada test ls llibpa pads
474. xpanded Name ChildRec Tag Text IO New Line Text IO Put Line ParentRec has an external tag of amp Ada Tags External Tag ParentRec Tag nu esce o Pe hime ChildRec has an external tag or T amp Ada Tags External_Tag ChildRec Tag nu Text IO New Line if child in ParentRec class then Text IO Put Line child a child rec is in ParentRec class else Text IO Put Line This should not happen end if if child in ChildRec class then Texe itio dei Ebbene ehild a child rec rs in ChildaRectelass else Text IO Put Line This should not happen file G Linux http www vaxxine com pegasoft people html book 12 html 21 of 35 7 20 2001 11 34 27 AM Big Online Book of Linux Ada Programming 12 Standard Gnat Packages end if end t Working with Tagged Record Tags ParentRec has an expanded name of T PARENTREC ChildRec has an expanded name of T CHILDREC ParentRec has an external tag of T PARENTREC ChildRec has an external tag of T CHILDREC child a chila rec is In ParentcRecl elass child a child rec is in ChildRec class 12 8 Tables Gnat 3 11 introduces gnat table a gnat package for creating an aribrary length array or for that matter a link list expand and give example program 12 9 Hash Tables Gnat provides a generic package for hash tables called gnat htable You provide gnat s package with informati
475. y conn webproj ppt2 It includes thousdands of source code examples bindings compilers and the official Ada 95 documentation The Ada Software Engineering Library has over 1 Gig of files It s available at http unicoi kennesaw edu ase index htm The Home for Brave Ada Programmers at www adahome com provides a lot of general reference material and bindings The Ada Information Clearinghouse AIC at www adaic com contains statistics studies and other general information http www skinner demon co uk aidan programming libra has a tool called Libra Library of Reusable Ada Code for many common data structures such as lists queues and Internet sockets such as HTTP and POP3 http www ainslie software com has a tool called AdaJNI Java Native Interface that lets you call java methods from Ada 95 Table of Contents Next Chapter gt file G Linux http www vaxxine com pegasoft people html book 1 html 4 of 5 7 20 2001 11 28 29 AM Big Online Book of Linux Ada Programming 1 Introduction file G Linux http www vaxxine com pegasoft people html book 1 html b of 5 7 20 2001 11 28 29 AM Big Online Book of Linux Ada Programming 2 Installing Gnat on Linux 2 Installating Gnat on Linux lt Last Chapter Table of Contents Next Chapter gt Gnat is a part of the gcc project The gcc command itself isn t a compiler it s a program that determines the kind of source file you have and runs the appropriate compiler for
476. y has to be explicitly deallocated Another standard generic you ll run into is unchecked_conversion This converts a variable of one type to another by physically copying to data from one to the other such as an array of 8 bits to a short_short_integer Although you can write generic subprograms most of the time you use generics will be for creating generic packages Generic packages have a spec and body like normal Ada packages but they begin with a list of parameters to the package that must be filled in when the generic is instantiated generic these are the parameters for the generic type ListElement is lt gt unspecified list element procedure left right ListElement a procedure to sort by package SimpleList is type List is array 1 100 of ListElement procedure Add 1 list e ListElement procedure Sort 1 list procedure Display 1 list end SimpleList check KB In this example SimpleList takes some kind of data type called a ListElement the items that compose the lists Besides lt gt Ada offers a number of other non specific type descriptors to give the compiler an idea of what kind of types are acceptable file G Linux http www vaxxine com pegasoft people html book 11 html 12 of 39 7 20 2001 11 33 45 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming Since the ListElement could be an aggregate and we can t assume
477. y ioctl type AFileID is new integer a file descriptor a new integer for safety procedure ioctl winsz Result out integer fid AFileID request integer IMO e lN OUt Nindowoizelnto N pragma import C ioctl winsz ioctl file G Linux http www vaxxine com pegasoft people html book 16 html 28 of 47 7 20 2001 11 37 15 AM Big Online Book of Linux Ada Programming 16 Advanced Linux Programming pragma import_valued_procedure ioctl_winsz ioctl get the size of the window function open path string flags integer return AFileID pragma import C open open open a file in this case the tty procedure close fid AFileID pragma import C close close close a file The Signal Handler protected body SignalHandler is procedure SizeChangeHandler is handle a window size change SIGWINCH fid AFileID opens file ID Result integer function result of ioctl Info WindowSizeInfo window size returned by ioctl begin fid Open dev tty amp ASCII NUL 0 ioctl winsz Result id TTOGWINSITZ Info if Result 0 then Put_Line Window is now amp info column img amp x amp info row img else Put Line ioctl reports an error end if Close sce end SizeChangeHandler end SignalHandler end sigwinch with Ada Text IO sigwinch useAda Text IO sigwinch
478. yOwing cp moneyOwing money 1 0 cp interest end chargeInterest procedure chargeInterest2 c in out aCustomerAccount is update the customer record by charging the interest begin c moneyOwing c moneyOwing money 1 0 c interest end chargeInterest2 function chargeInterest3 cp access aCustomerAccount return boolean is update the customer record by charging the interest if under 1000 don t charge interest and return false begin if cp moneyOwing 1000 0 then file G Linux http www vaxxine com pegasoft people html book 11 html 20 of 39 7 20 2001 11 33 46 AM Big Online Book of Linux Ada Programming 11 Advanced Ada Programming return false end if cp moneyOwing cp moneyOwing money 1 0 cp interest return true end chargeInterest3 CE aCustomerPtr begin Put_Line An Example of Access Parameters New_Line cp new aCustomerAccount Put_Line chargeInterest uses an access parameter cp moneyOwing 1500 0 Put Line Charging interest on amp cp moneyOwing img chargeInterest cp Put Line After interest money owing is amp cp moneyOwing img New Line Put Line chargeInterest2 uses an in out parameter cp moneyOwing 1700 0 Put Line Charging interest on amp cp moneyOwing img chargeInterest2 cp all Put Line After interest money owing is amp cp moneyOwing img New Line
479. yone Linux distributions CD ROMs with the Linux kernel and various other software ready for installation do not have to be free but the Linux source code must remain available Making source code available is known as open source The word Linux is properly pronounced using a Swedish accent making it difficult to pronounce in North America It is most often pronounced with a short i and with the first syllable stressed as in LIH nicks but it is sometimes pronounced LYE nicks the anglicized Linus UNIX or LEE nucks Strickly speaking Linux refers to the operating system kernel that starts and manages other programs and provides access to system resources The various open source shells compilers standard libraries and commands are a part of another project called GNU The GNU project was started by the Free Software Foundation FSF as an an attempt to create a free version of UNIX The main Linux C compiler gcc is a part of the GNU project There is also a GNU kernel project but this has been largely superseded by the Linux kernel X Windows is also not strictly a part of Linux Xfree86 the free version of X Windows was adapted to the Linux operating system 1 2 1995 The Year of Ada and Gnat In 1974 the US Department of Defense realized it was spending too much on software They wanted a new computer language that could handle all of their needs from controlling the hardware in a missile guidance system to doing arti
480. z Distribution stub generation r s for receiver sender stubs gnatZ Use zero cost exception handling gnat83 Enforce Ada 83 restrictions jgnatmake will create two files hello class and ada_hello class To run the program under the Java interpreter type file G Linux http www vaxxine com pegasoft people html book 19 html 3 of 4 7 20 2001 11 38 32 AM Big Online Book of Linux Ada Programming 19 Specialized Topics java hello Table java switches Java Interpreter Switch Description 00000 help Print usage info l version Print versionnumber mx size Maximum heap size ms size malhepsze las size Heap increment classpath path Seclasspth verify JVefyalbytecode verifyremote Verifybytecodeloadedfromnetwork noverify Do not verify any bytecode Dproperty value Seta property verbosegc Print message during garbage collection noclassgc jDisableclassgaragecolection v verbose Be verbose verbosejit jPrintmessageduringJITcodegeneraion verbosemem Print detailed memory allocation statistics debug memetodcals noasyncgc jDonotgabagecolleetasynchronusy cs checksource Check source against class files 0 jar Executable isa JAR Limitations Ada streams don t work with Jgnat 19 2 ASIS Information on ASIS is available at http

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