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HP gnu source-level debugger 5992-4701 User's Manual

1. if expr cmds cmds if expr cmds else cmds end I info many kinds show many kinds k k 16 8 5 L Table 16 25 L XDB Command Equivalent WDB Command 1 with xdb info args followed by info locals L L with xdb la No equivalent lb lb with xdb ib le string Ic string with xdb info common string ld ld with xdb show directories 1f lf with xdb info sources 1f string No equivalent lg string lg string with xdb info variables string 11 string info functions string info variables string maint print msymbol1s file 16 8 Alphabetical lists of XDB commands and HP WDB equivalents 273 Table 16 25 L continued XDB Command lm string Equivalent WDB Command show user string lo class string info func class string lp info functions lp class string info func class string info addr class string lpm No equivalent lr Ir with xdb info all reg lr string Ir string with xdb info reg string ls string No equivalent 16 8 6 M through P Table 16 26 M through P XDB Command M t c expr expr 17 Iz with xdb info signals Equivalent WDB Command No equivalent mm info sharedlibrary mm string No equivalent N fo or rev n fo or rev p expr format
2. 1 5 Stepping to the next line in the source program Now we use the command n next to advance execution to the next line of the current function 20 A Sample GDB Session gdb n 882 set_quotes argc gt 2 TOKEN DATA TEXT argv 1 nil 1 6 Stepping into a subroutine The set_quotes looks like a promising subroutine We can go into it by using the command s step instead of next step goes to the next line to be executed in any subroutine so it steps into set_quotes gdb s set_quotes lq 0x34c78 lt QUOTE gt rq 0x34c88 lt UNQUOTE gt at input c 530 530 if lquote def lquote 1 7 Examining the Stack The display that shows the subroutine where m4 is now suspended and its arguments is called a stack frame display It shows a summary of the stack We can use the backtrace command which can also be spelled bt to see where we are in the stack as a whole the backt race command displays a stack frame for each active subroutine gdb bt 0 set _quotes lq 0x34c78 lt QUOTE gt rq 0x34c88 lt UNQUOTE gt at input c 530 1 0x6344 in m4_changequote argc 3 argv 0x33c70 at builtin c 882 2 0x8174 in expand macro sym 0x33320 at macro c 242 3 0x7a88 in expand_token obs 0x0 t 209696 td 0xf7fffa30 at macro c 71 4 Ox79dc in expand_input at macro c 40 5 0x2930 in main argc 0 argv Oxf7fffb20 at m4 c 195 We step through a few more lines to see what happens The first two
3. 22 Reporting Bugs in GDB Your bug reports play an essential role in making GDB reliable Reporting a bug may help you by bringing a solution to your problem or it may not But in any case the principal function of a bug report is to help the entire community by making the next version of GDB work better Bug reports are your contribution to the maintenance of GDB In order for a bug report to serve its purpose you must include the information that enables us to x the bug 22 1 Have you found a bug If you are not sure whether you have found a bug here are some guidelines e Ifthe debugger gets a fatal signal for any input whatever that is a GDB bug Reliable debuggers never crash e IfGDB produces an error message for valid input that is a bug Note that if you re cross debugging the problem may also be somewhere in the connection to the target e If GDB does not produce an error message for invalid input that is a bug However you should note that your idea of invalid input might be our idea of an extension or support for traditional practice e If you are an experienced user of debugging tools your suggestions for improvement of GDB are welcome in any case 22 2 How to report bugs If you obtained GDB Hewlett Packard Wildebeest based on GDB 5 0 hpwdb 20000516 as part of your HP ANSI C HP ANSI C or HP Fortran compiler kit report problems to your HP Support Representative If you obtained GDB Hewlett
4. E Unset the environment variable PA_DEBUG Restore the original value of the SHELL environment variable The rest of the debugging operations are the same as that on the HP 9000 HP UX platform NOTE Make sure that the user has write permission on tmp directory and that there is enough space to create a temporary file of one page size as obtained by sysconf _SC_PAGE_SIZE system call 14 30 1 1 Limitations of GDB Support under ARIES No support for debuggers other than HP 9000 HP UX GDB for debugging HP 9000 applications under ARIES on HP UX 11i Integrity servers No support for old GDB versions of HP UX 10 20 and earlier However debugging of HP UX 10 20 applications using a HP UX 11 0 and newer HP 9000 GDB is supported HP 9000 GDB behaves differently for child processes created using fork and vfork system calls ARIES emulates fork and vfork system calls 14 30 Debugging with ARIES 231 identically The exact behavior shown by HP 9000 GDB under ARIES may differ from that on a HP 9000 HP UX server e Ifthe debugged process is blocking in a system call any attempt to get to the GDB command prompt by pressing ctrl C does not work The process needs to be killed from a different shell e ARIES does not provide true emulation of MxN threads and thus does not support debugging of HP 9000 applications that are linked with pthreads library and create threads in MxN model A NOTE The HP 9000 applications l
5. show envvar show paths show environment varname set environment varname value unset environment varname path directory Running Programs Under GDB List all the environment variables used by GDB Display the list of search paths for executables the PATH environment variable Print the value of environment variable varname to be given to your program when it starts If you do not supply varname print the names and values of all environment variables to be given to your program You can abbreviate environment as env Set environment variable varname to value The value changes for your program only not for GDB itself The value may be any string the values of environment variables are just strings and any interpretation is supplied by your program itself The value parameter is optional if it is eliminated the variable is set to a null value For example this command set env USER foo tells the debugged program when subsequently run that its user is named foo The spaces around are used for clarity here they are not actually required Remove variable varname from the environment to be passed to your program This is different from set env varname unset environment removes the variable from the environment rather than assigning it an empty value Add directory to the front of the PATH environment variable the search path for executables for both GDB and your program You may
6. Example gdb break delete 1 done gdb break list done BreakpointTable nr_ rows 0 nr_cols 6 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col_name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alignment 1 col_name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colhdr What body gdb The break disable command Synopsis break disable breakpoint Disable the named breakpoint s The field enabled in the break list is now set to n for the named breakpoint s GDB command The corresponding GDB command is disable Example gdb break disable 2 done gdb 314 The GDB MI Interface break list done BreakpointTable nr_ rows 1 nr_cols 6 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col_name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alignment 1 col_name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colhdr What body bkpt number 2 type breakpoint disp keep enabled n addr 0x000100d0 func main file hello c line 5 times 0 gdb The break enable command Synopsis bre
7. Repeating a List command with RET discards the argument so it is equivalent to typing just 1ist This is more useful than listing the same lines again An exception is made for an argument of that argument is preserved in repetition so that each repetition moves up in the source file In general the 1ist command expects you to supply zero one or two linespecs Linespecs specify source lines There are several ways of writing them but the most common way is to specify some source line 7 1 Printing source lines 77 7 2 Searching source files 78 The following arguments can be given to the 1ist command list linespec list first last list last list first list list list Print lines centered around the line specified by linespec Print lines from first to last Both arguments must be linespecs Print lines ending with last Print lines starting with first Print lines just after the lines last printed Print lines just before the lines last printed As described in the preceding table A single source line can be specified in the following ways number offset offset filename number function filename function address Specifies line number of the current source file When a list command has two linespecs this refers to the same source file as the first linespec Specifies the line offset lines after the last line printed When used as the second linespec ina 1ist command that has
8. line 9 times 1 bkpt number 2 type wathpoint disp keep enabled y addr what j times 1 gdb exec continue running gdb stopped reason watchpoint scope wpnum 2 thread id 1 frame addr 0x000029ec func main args file hello c line 18 gdb break list 21 5 GDB MI breakpoint table commands 319 done BreakpointTable nr_rows 1 nr_cols 6 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col_name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alignment 1 col _name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colhdr What body bkpt number 1 type breakpoint disp keep enabled y addr 0x000029b4 func call file hello c line 9 times 1 gdb 21 6 GDB MI Data manipulation This section describes the GDB MI commands that manipulate data examine memory and registers evaluate expressions and so on The data disassemble command Synopsis data disassemble s start addr e end addr filename 1 linenum n lines mode Where start addr is the beginning address or pc end addr is the end address filename is the name of the file to disassemble linenum is the line number to disassemble around lines is the number of disassembly lines to be produced If it is
9. nopass GDB should not allow your program to see this signal When a signal stops your program the signal is not visible to the program until you continue Your program sees the signal then if pass is in effect for the signal in question at that time In other words after GDB reports a signal you can use the handle command with pass or nopass to control whether your program sees that signal when you continue You can also use the signal command to prevent your program from seeing a signal or cause it to see a signal it normally would not see or to give it any signal at any time For example if your program stopped due to some sort of memory reference error you might store correct values into the erroneous variables and continue hoping to see more execution but your program would probably terminate immediately as a result of the fatal signal once it saw the signal To prevent this you can continue with signal 0 See Giving your program a signal page 121 5 4 Stopping and starting multi thread programs When your program has multiple threads see Debugging programs with multiple threads page 46 you can choose whether to set breakpoints on all threads or on a particular thread break linespec thread linespec specifies source lines there are several threadno break linespec ways of writing them but the effect is always to thread threadno if specify some source line Use the qualifier thread threadno witha
10. string string with xdb Search source forward for last search regexp forw string regexp string string with xdb Search source backward for last rev regexp string D dir D dir with xdb dir Adda directory search path for pathname source files L L with xdb Show current viewing location or current point of execution 16 1 By function lists of XDB commands and HP WDB equivalents 255 Table 16 3 File viewing commands continued sources XDB Command WDB Equivalent Meaning ld ld with xdb show List source directory search path directories list all directories IF 1f with xdb info List all source files lf string No equivalent List matching files n fo or rev Repeat previous search N fo or rev Repeat previous search in opposite direction v v with xdb list Show one source window forward from current v location va address v location with xdb list location va address with xdb disas address View source at locationin source window View address in disassembly window va label va label with xdb disas label View label in disassembly window label is a location va label offset va label offset with xdb disas label offset 16 1 4 Source directory mapping commands View label offset in disassembly window Use the D or dir command to add new directories to be searched for source files See
11. 14 13 Debugging multiple processes programs with fork and vfork calls 14 13 1 Ask mode for set follow fork mode The ask command prompts the user to select between parent and child as the debugger response to a program call of fork vfork Based on the user selection the parent or the child process is debugged For example gdb set follow fork mode ask gdb show follow fork mode The debugger response to a program call to fork or vfork is ask gdb run Starting program sample New process 4941 Select follow fork mode 0 parent 1 child 14 13 2 Serial mode for set follow fork mode The option serial for the 01 1low fork mode command enables debugging of a parent and child process within a debugger session During a debug session if the parent process forks a child the debugger starts debugging the child process When the child process exits the debugger switches back to the parent process The ollow fork mode will work only if there is a wait call by the parent process This feature is enabled by setting the ol low fork mode flag to serial as specified in the following example gdb set follow fork mode serial The follow fork mode is not supported under following conditions e MxN threaded programs e Parent process is 32 bit and child process is 64 bit and vice versa For the follow fork mode to work both parent and child process must be of the same mode 14 13 3 Support for showing unwind info The mai
12. Imaginary values cannot be assigned to variables because there is no imaginary data type You can take a normal number and multiply it by an imaginary number and get another imaginary number You can take a normal number and add it to an imaginary number to get a complex number Complex numbers cannot be used in arithmetic expressions in the debugger For more information of _Complex type refer to the HP C ANSI C documentation 14 25 5 Support for debugging namespaces This release of HP WDB provides full support for debugging namespaces 222 HP UX Configuration Specific Information You do not need to use fully qualified names to access symbols within a namespace The debugger can compile a list of namespaces active in the scope that you are in and when possible choose an appropriate symbol The debugger recognizes using declarations using directives namespace aliases nested namespaces and unqualified lookup within a namespace It also recognizes using directives and aliases and using declarations within namespaces When the debugger has a list of possible resolutions for a given symbol it displays a menu that shows all names fully qualified whenever namespaces are involved You can choose the appropriate symbol from the list For example if you stop the debugger in a function that contains an inti using directive for a namespace such as using namespace A AB ABC ABCD You can use the command print i and if the only possi
13. List of commands info Generic command for showing things about the program being debugged show Generic command for showing things about the debugger Type help followed by command name for full documentation Command name abbreviations are allowed if unambiguous gdb help command With a command name as help argument GDB displays a short paragraph on how to use that command apropos args The apropos args command searches through all of the GDB commands and their documentation for the regular expression specified in args It prints out all matches found For example apropos reload results in set symbol reloading Set dynamic symbol table reloading multiple times in one run show symbol reloading Show dynamic symbol table reloading multiple times in one run complete args Thecomplete argscommand lists all the possible completions for the beginning of a command Use args to specify the beginning of the command you want completed For example complete i results in if ignore info inspect This is intended for use by GNU Emacs In addition to help you can use the GDB commands info and show to inquire about the state of your program or the state of GDB itself Each command supports many topics of inquiry this manual introduces each of them in the appropriate context The 36 GDB Commands listings under info and under show in the Index point to all the sub commands See 222 info set
14. NOTE The files lt executable name gt and output_dir lt path gt options are exclusive to batch mode debugging 14 10 10 Heap Profiling The heap profile is useful for identifying how memory is being used by the program You can use WDB to profile an application s current heap usage 14 10 10 1 Commands for heap profiling info heap Displays a heap report listing information such as the start of the heap end of the heap heap allocations size of blocks and number of instances The report shows heap usage at the point you use the info heap command The report does not show allocations that have already been freed For example if you make several allocations free them all and then you use info heap the result does not show any allocations info heap filename Writes heap report output to the specified file info heap idnumber Produces detailed information on the specified heap allocation including the allocation call stack set heap check frame count Controls the depth of the call stack collected num Larger values increase run time The default value is four 4 stack frames 178 HP UX Configuration Specific Information show heap check Displays all current settings for memory checking 14 10 10 2 info heap arena The info heap arena command enables the user to view high level memory usage details of each arena The info heap arena is not supported in batch mode This command is available only for applications ru
15. e down finish frame info e next step tbreak e rbreak e up 14 29 Debugging optimized code 227 The following commands are not affected by the optimization level of the program being debugged e attach e catch commands continue e core e delete e define e detach e disable enable e file e forw e handle e help e ignore e kill e load e nexti e path e quit e rev e run set args set env set lt param gt show args show lt param gt e signal e source e stepi e symbol target be tty e undisplay e unset env until 228 HP UX Configuration Specific Information 14 29 1 Debugging Optimized Code at Various Optimization Levels The following sections describe debugging optimized code support at each optimization level 14 29 11 00 and 01 At 01 level optimizations that affect the user visible state of a program are avoided Line numbers are accurately associated with each machine instruction Global or local variables may be examined except for unused variables which may be eliminated New values may be assigned to a global and a local variable set lt var gt lt expression gt when stepping by line step next break lt line gt However while stepping by instruction stepi nexti at optimization level O1 assign a value to a variable only if stopped at the very first instruction This is a must as local optimizations are pe
16. frame func main args file try c line 5 gdb data list changed registers done changed registers o WEN I2 4 WE MEM Wey WON Wows MPO N Ud Bek Se Be Le od ie LC Es ATE eal A TE Lem ee 24 25 26 27 28 30 31 64 65 66 67 69 gdb The data list register names command Synopsis data list register names regno Show a list of register names for the current target If no arguments are given it shows a list of the names of all the registers If integer numbers are given as arguments it will print a list of the names of the registers corresponding to the arguments To ensure consistency between a register name and its number the output list may include empty register names GDB command GDB does not have a command which corresponds to data list register names In gdbtk there is a corresponding command gdb _regnames Example For the PPC MBX board 21 6 GDB MI Data manipulation 323 gdb data list register names done register names r0 r1 r2 3 r4 5 rE 7 We Oy TEI i a A OLA ELTH Lb a Bee Wel anh r14 EIS We lo ELZ rig ELON r20 MEZ RI We 22 We 230s r24 E250 t26 T2 fale WeDo WHEDON x r30 UE ae A LPO EELT EEDI WEBM NEAN WEBI fe Le fe fg E LOI WETEA METZI CETS TELAI WETS ETGT CETTE f18 WE LOM f20 WEDS WEDD WEDS E24 WEQ5 f26 WED f28 WEQZON F30 ESLI Tia Tipat ops t Tert tirer
17. gdb set var g 4 GDB allows more implicit conversions in assignments than C you can freely store an integer value into a pointer variable or vice versa and you can convert any structure to any other structure that is the same length or shorter To store values into arbitrary places in memory use the construct to generate a value of specified type at a specified address see Expressions page 83 For example int 0x83040 refers to memory location 0x83040 as an integer which implies a certain size and representation in memory and set int 0x83040 4 stores the value 4 into that memory location 11 2 Continuing at a different address Ordinarily when you continue your program you do so at the place where it stopped with the cont inue command You can continue at a selected address using one of the following commands jump linespec Resume execution at line 1inespec Execution stops again immediately if there is a breakpoint there See Printing source lines page 77 for a description of the different forms of linespec It is common practice to use the tbreak command in conjunction with j ump See Breakpoints page 51 The j ump command does not change the current stack frame the stack pointer the contents of any memory location or any register other than the program counter If line 1inespecis ina different function from the one currently executing the results may be bizarre if the two functio
18. thread select threadnum Make threadnum the current thread It prints the number of the new current thread and the topmost frame for that thread GDB command The corresponding GDB command is thread Example gdb exec next 354 The GDB MI Interface running gdb 0x7 7 0aec stopped reason end stepping range thread id 2 frame addr 0x00002ca4 func printme args name ip file multithread c line 9 gdb thread list ids done thread ids thread id 2 thread id 1 number of threads 2 gdb thread select 1 done new thread id 1 frame level 0 addr 0x7ad47d70 func _lwp create 0x10 args from usr lib libpthread 1 gdb 21 13 GDB MI tracepoint commands The tracepoint commands are not yet implemented 21 14 GDB MI variable objects A Motivation for variable objects in GDB MI For the implementation of a variable debugger window locals watched expressions and so on we are proposing the adaptation of the existing code used by Insight The two main reasons for that are 1 Ithas been proven in practice it is already on its second generation 2 It will shorten development time needless to say how important it is now The original interface was designed to be used by Tcl code so it was slightly changed so it could be used through GDB MI This section describes the GDB MI operations that will be available and gives some hints about their use NO
19. up 1 0x22f0 in main argc 1 argv Oxf7fffbf4 env 0xf7fffbfc at env c 10 10 read_input_file argv i After such a printout the 1ist command with no arguments prints ten lines centered on the point of execution in the frame See Printing source lines page 77 up silently n These two commands are variants of up and down down silently n respectively they differ in that they do their work silently without causing display of the new frame They are intended primarily for use in GDB command scripts where the output might be unnecessary and distracting 6 6 Information about a frame 74 The following commands are used to print information about the selected stack frame frame f When used without any argument this command does not change which frame is selected but prints a brief description of the currently selected stack frame It can be abbreviated With an argument this command is used to select a stack frame See Selecting a frame page 73 Examining the Stack info ia info info info info info frame info frame addr f addr args locals catch This command prints a verbose description of the selected stack frame including e the address of the frame e the address of the next frame down called by this frame e the address of the next frame up caller of this frame e the language in which the source code corresponding to this frame is written e the address of the fram
20. z zfield 8 ignore count z zfield 9 commands Note that address is intended for user consumption the syntax varies depending on the language The output ends with Z Zbreakpoints table end 20 9 Invalidation notices The following annotations say that certain pieces of state may have changed z zframes invalid The frames for example output from the backtrace command may have changed z zbreakpoints invalid The breakpoints may have changed For example the user just added or deleted a breakpoint 20 10 Running the program When the program starts executing due toa GDB command such as step or continue Z Zstarting is output When the program stops Z Zstopped 20 9 Invalidation notices 303 is output Before the stopped annotation a variety of annotations describe how the program stopped Z Zexited exit status The program exited and exit status is the exit status zero for successful exit otherwise nonzero Z Zsignalled The program exited with a signal After the Z Zsignalled the annotation continues intro text Z Zsignal name name Z Zsignal name end middle text Z Zsignal string string Z Zsignal string end end text where name is the name of the signal such as SIGILL or SIGSEGV and st ringis the explanation of the signal such as Illegal Instruction or Segmentation fault intro text middle text and end text are for the user s benefit and have no particular format Z Z
21. 1 the whole function will be disassembled in case no end addr is specified If end addr is specified as a non zero value and lines is lower than the number of disassembly lines between start addrand end addr only lines lines are displayed if lines is higher than the number of lines between start addr and end addr only the lines up to end addr are displayed mode is either 0 meaning only disassembly or 1 meaning mixed source and disassembly Result The output for each instruction is composed of four fields e Address e Func name e Offset e Instruction Note that whatever included in the instruction field is not manipulated directly by GDB MI that is it is not possible to adjust its format 320 The GDB MI Interface GDB command There is no direct mapping from this command to the CLI Example Disassemble from the current value of Spc to pc 20 gdb data disassemble s Spc e Spc 20 0 done asm_insns address 0x000107c0 func name main offset 4 inst mov 2 00 address 0x000107c4 func name main offset 8 inst sethi hi 0x11800 02 address 0x000107c8 func name main offset 12 inst or 02 0x140 o1 t 0x11940 lt lib version 8 gt address 0x000107cc func name main offset 16 inst sethi hi 0x11800 02 address 0x000107d0 func name main offset 20 inst or 02 0x168 04 t 0x11968 lt lib version 48 gt gdb Dis
22. 13 value 0x4544 number 14 value 0xffdffff number 15 value 0xffffffff number 16 value 0xfffffeft number 17 value 0xefffffed number 18 value 0xfffffffe number 19 value 0xfff fFfff number 20 value 0xffLLLLLE number 21 value 0xffffffff number 22 value 0xffffffF7 number 23 value 0xfff fFfff number 24 value 0xffLLLLLLE number 25 value 0xfff fFfff number 26 value 0xfffffffb number 27 value 0xffffFfff number 28 value 0xf7bfffff number 29 value 0x0 number 30 value 0xfe010000 number 31 value 0x0 number 32 value 0x0 number 33 value 0x0 number 34 value 0x0 number 35 value 0x0 number 36 value 0x0 number 37 value 0x0 number 38 value 0x0 number 39 value 0x0 number 40 value 0x0 number 41 value 0x0 number 42 value 0x0 number 43 value 0x0 number 44 value 0x0 number 45 value 0x0 number 46 value 0x0 number 47 value 0x0 number 48 value 0x0 number 49 value 0x0 number 50 value 0x0 number 51 value 0x0 number 52 value 0x0 number 53 value 0x0 number 54 value 0x0 number 55 value 0x0 number 56 value 0x0 number 57 value 0x0 number 58 value 0x0 number 59 value 0x0 number 60 value 0x0 number 61
23. 2560 section size 6668 total sent 2560 total size 9880 download section text section sent 3072 section size 6668 total sent 3072 total size 9880 download section text section sent 3584 section size 6668 total sent 3584 total size 9880 download section text section sent 4096 section size 6668 total sent 4096 total size 9880 download section text section sent 4608 section size 6668 total sent 4608 total size 9880 download section text section sent 5120 section size 6668 total sent 5120 total size 9880 download section text section sent 5632 section size 6668 total sent 5632 total size 9880 download section text section sent 6144 section size 6668 total sent 6144 total size 9880 download section text section sent 6656 section size 6668 total sent 6656 total size 9880 download section init section size 28 total size 9880 download section fini section size 28 total size 9880 download section data section size 3156 total size 9880 download section data section sent 512 section size 3156 total sent 7236 total size 9880 download section data section sent 1024 section size 3156 total sent 7748 total size 9880 download section data section sent 1536 section size 3156 total sent 8260 total size 9880 download section
24. 9 1 3 Having GDB infer the source language nnd uihedentastiveonsiaiieuastasin 102 9 2 Displaying th languag escoi irran ane a aa eei ooet area eNi laee iia 103 9 3 Type and fange checkiNgereici din eae E T a ea a EK aA aae 103 9 3 1 An overview of type CHECKING 3412 cecslestaa weszeichess ts octacesaocssbensnneliashuntestns eweade sarees 103 9 3 2 An overview of range CHECKING oiscs svetcveebcohutvcuslstess andtads reesieeeteonaeteaisiiteatiacs tt 104 94 Supported aN Uae OSes ice cwiiseross acetiess tap a ie ea o aaeei ea OEA E EE AEE SE 105 TAIC Gna a Gls pr fe r 106 94 Vl Cand CaP OP er ators ics caesayekcintevescsbsieviatay sure senivassGcee Navas cose esatay Ea 106 9 4 1 2 C aridd C CONSUANIUS cceecccsccnnvvsccnencescssnnovscannnsvssechnovseanensescstnnovscannnsveseshn 108 9 4 T3 KAT IEX PRESSION S oai E EE E E carrie aa neta eae E 109 9 4 1 4 C and Crrdefatlis asserere T AEA EEEE 110 9 4 1 5 C and C type and range Checks scchacetaete ieee Mave ii ae 110 OA rG DB and Aeae a a E a a 111 94 1 7 GDB features for CHR iivesccsvsec oiT Ara A E ETEN TNE EAE 111 e AG KOT c 9 WETEA E E A E EA E E AE A EEE EE EE AO BAE ERE 112 94 21 Fortran typeset iii neeo aa tus EO EE S a Taat 112 942 2 Fortran operators seerne arere A eTa es web oie a ea A ee E EANA E aaa easa 113 942 3 Fortran Special 155UESitirsr atap oaae a a Ea TEA A 114 10 Examining the Symbol Table ssi2 5 31235 lt i nsssincs deta sedeatachubseasebtpnsiceoeadetedalva
25. Initialize the ignore count i Insert a regular breakpoint in all the functions whose names match the given regular expression Other flags are not applicable to regular expression Result The result is in the form done bkptno number func funcname file filename line l1lineno where number is the GDB number for this breakpoint funcname is the name of the function where the breakpoint was inserted filename is the name of the source file which contains this function and 1ineno is the source line number within that file EY NOTE This format is open to change GDB command The corresponding GDB commands are break tbreak hbreak thbreak and rbreak Example gdb break insert main 316 The GDB MI Interface done bkpt number 1 type breakpoint disp keep enabled y addr 0x0001072c file recursive2 c line 4 times 0 gdb break insert t foo done bkpt number 2 type breakpoint disp keep enabled y addr 0x00010774 file recursive2 c line 11 times 0 gdb break list done BreakpointTable nr_ rows 2 nr_cols 6 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col_name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alignment 1 col_name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignmen
26. args name intarg name strarg frame level 3 args name intarg name strarg name fltarg frame level 4 args gdb stack list arguments 1 done stack args frame level 0 args frame level 1 args name strarg value 0x11940 A string argument frame level 2 args name intarg value 2 name strarg value 0x11940 A string argument frame level 3 args name intarg value 2 name strarg value 0x11940 A string argument name fltarg value 3 5 frame level 4 args gdb stack list arguments 0 2 2 done stack args frame level 2 args name intarg name strarg gdb stack list arguments 1 2 2 done stack args frame level 2 args name intarg value 2 name strarg value 0x11940 A string argument gdb The stack list frames command Synopsis stack list frames low frame high frame List the frames currently on the stack For each frame it displays the following info level The frame number 0 being the topmost frame that is the innermost function addr The pc value for that frame func Function name file File name of the source file where the function lives line Line number corresponding to the pc If invoked without arguments this command prints a backtrace for the whole stack If given two integer arguments it shows the frames wh
27. backtrace command it annotates it as follows Z Zarg begin argument name Z Zarg name end separator string Z Zarg value value flags the value Z Zarg end where argument name is the name of the argument separator string is text which separates the name from the value for the user s benefit such as and value flags and the value have the same meanings as in a value history begin annotation When printing a structure GDB annotates it as follows Z Zfield begin value flags field name Z Zf ield name end separator string 298 GDB Annotations z zfield value the value z zfield end where field name is the name of the field separator string is text which separates the name from the value for the user s benefit such as and value flags and the value have the same meanings as ina value history beginannotation When printing an array GDB annotates it as follows Z Zarray section begin array index value flags where array index is the index of the first element being annotated and value flags has the same meaning as ina value history begin annotation This is followed by any number of elements where the element can be either a single element or a repeated element as shown in the examples below 1 whitespace omitted for the first element the value 7 Zelt 1 whitespace omitted for the first element the value Z Zelt rep number of repititions repetition
28. breakpoint command to specify that you only want GDB to stop the program when a particular thread reaches this breakpoint threadnois one of the numeric thread identifiers assigned by GDB shown in the first column of the info threads display If you do not specify thread threadno when you set a breakpoint the breakpoint applies to all threads of your program You can use the thread qualifier on conditional breakpoints as well in this case place thread threadno before the breakpoint condition like this gdb break frik c 13 thread 28 if bartab gt lim 5 4 Stopping and starting multi thread programs 69 70 Whenever your program stops under GDB for any reason all threads of execution stop not just the current thread This allows you to examine the overall state of the program including switching between threads without worrying that things may change underfoot Conversely whenever you restart the program all threads start executing This is true even when single stepping with commands like step or next In particular GDB cannot single step all threads in lockstep Since thread scheduling is up to your debugging target s operating system not controlled by GDB other threads may execute more than one statement while the current thread completes a single step Moreover in general other threads stop in the middle of a statement rather than at a clean statement boundary when the program stops You might even find
29. class string lr lr with xdb info List all registers all reg lr string lr string with xdb List matching registers info reg string ls string No equivalent List all or matching special variables mm info sharedlibrary Show memory map of all loaded shared libraries mm string No equivalent Show memory map of matching loaded shared libraries p expr format pl format expr Note The Print value using the specified count and size portions of format formats are not allowed in the p print command They are allowed in the x command examine memory 16 1 By function lists of XDB commands and HP WDB equivalents 257 Table 16 4 Data viewing and modification commands continued XDB Command p expr format WDB Equivalent p format amp amp expr Meaning Print address using specified for mat p class No equivalent Print static members of class p lang show language Inquire what language is used p format Use x format command to Print value of next previous obtain initial value then use x memory location using format with no argument to obtain value of next memory location To obtain value of previous memory location use x _ 1 pq expr set expr set var expr Evaluate using the specified format pq expr format No equivalent Determine address using specified format pq class No equivalent Evaluate static members of class pq format 16 1 6
30. data section sent 2048 section size 3156 total sent 8772 total size 9880 download section data section sent 2560 section size 3156 total sent 9284 total size 9880 download section data section sent 3072 section size 3156 total sent 9796 total size 9880 done address 0x10004 load size 9880 transfer rate 6586 write rate 429 gdb The target exec status command Synopsis target exec status Provide information on the state of the target whether it is running or not for instance GDB command There is no equivalent GDB command 21 11 GDB MI Target Manipulation Commands 351 Example N A The target list available targets command Synopsis target list available targets List the possible targets to connect to GDB command The corresponding GDB command is help target Example N A The target list current targets command Synopsis target list current targets Describe the current target GDB command The corresponding information is printed by info file among other things Example N A The target list parameters command Synopsis target list parameters GDB command No equivalent Example N A 352 The GDB MI Interface The target select command Synopsis target select type parameters Connect GDB to the remote target This command takes two args typ
31. e Add new structure fields to the end of a structure type object e Set breakpoints in and single step within redefined code 14 7 Fix and continue debugging 147 A NOTE You must rebuild the program after you use the fix command because the changes you make are temporarily patched into the executable image The changes are lost if you load a different executable and are not re ected in the original executable when you exit the debugger 14 7 4 Example Fix and Continue session This example shows how you can make and test changes to a function without leaving the debugger session Here is a short sample C program with an error int sum num int num int j total 0 for j 0 J lt num J total num main int num 10 printf The sum from 1 to d is d n num sum num 1 Compile the program cc sum c g o mysum usr ccs bin ld Warning At least one PA 2 0 object file sum o was detected The linked output may not run on a PA 1 x system 2 Run the program mysum The sum from 1 to 10 is 0 This result is obviously wrong We need to debug the program 3 Run the debugger gdb mysum HP gdb 3 0 for PA RISC 1 1 or 2 0 narrow HP UX 11 00 Copyright 1986 2001 Free Software Foundation Inc Hewlett Packard Wildebeest 3 0 based on GDB is covered by the GNU General Public License Type show copying to see the conditions to change it and or distribute copies Ty
32. include lt stdlib h gt int main char str str char malloc 15 strepy str hihi hikh return 0 gdb find amp str 0 amp str 15 hi 0x400123e0 0x400123e2 0x400123e5 3 patterns found gdb find 2 amp str 0 amp str 15 hi 0x400123e0 0x400123e2 2 patterns found gdb find 2b amp str 0 amp str 15 0x68 0x400123e0 0x400123e2 2 patterns found gdb find 2b amp str 0 10 0x68 0x400123e0 0x400123e2 2 patterns found gdb find 2b amp str 0 10 0x68 0x69 0x400123e0 0x400123e2 2 patterns found gdb find amp str 0 amp str 15 hi hi 0x400123e0 1 pattern found The following examples provide sample usages of the different parameters in the find command e Using the start address start address end address end address and patterns expri1 expr2 gdb find amp a 0 amp a 10 el 1 2 patterns found 198 HP UX Configuration Specific Information where amp a 0 Specifies the start address of the memory address range amp a 10 Specifies the end address of the memory address range e T Specifies the pattern Using the start address start address length 1ength parameter and a pattern expr1 find amp str 0 11 hihi amp str 0 Specifies the starting address 11 Specifies the length of the memory address range starting from amp str 0 Hihi Specifies the pattern expr1 Using the max
33. lt pid gt e Alternately you can attach the process to the debugger and consequently invoke thread debugging as follows gdb lt executable gt lt pid gt gdb set thread check on 14 11 5 Thread Debugging in Batch Mode HP WDB supports batch mode of debugging threads for HP UX 11iv2 and later on Integrity systems and on HP UX 11i v3 in PA RISC systems for 64 bit applications The debugger provides a log file with the list of thread related errors that occur in the application In batch mode the debugger detects the all the thread conditions that are detected during an interactive debugging session The debugger reports extended information such as variable address name id and other specifications related to the involved pthread objects In addition it displays the stack trace of the executing thread at the point of error 14 11 Thread Debugging Support 189 A NOTE Usethe set frame count setting in the rtconfig file to control the depth of the stack trace file This command controls the depth of the call stack collected Larger values increase the run time 14 11 5 1 Pre requisites for Batch mode of Thread Debugging The various prerequisites for Batch mode of Thread Debugging are as follows The thread debugging feature in HP WDB is dependent on the availability of the dynamic linker version B 11 19 Advanced thread debugging feature requires the pthread tracer library which is available by default on systems runni
34. or if GDB is unable to locate the saved registers the selected stack frame makes no difference 8 11 Printing Floating Point Values You can print the values of floating point registers in different formats To print both single and double precision values gdb info reg fr5 fr5 single precision 10 1444092 fr5 To get the bit pattern try the following macro define pbits set float sp Sarg0 p x int sp end This is what the macro produces gdb pbits fr6 1 0x4082852d 8 12 Floating point hardware Depending on the configuration GDB may be able to give you more information about the status of the floating point hardware info float Display hardware dependent information about the floating point unit The exact contents and layout vary depending on the floating point chip Currently info float is supported on the ARM and x86 machines 8 11 Printing Floating Point Values 99 100 9 Using GDB with Different Languages Although programming languages generally have common aspects they are rarely expressed in the same manner For instance in ANSI C dereferencing a pointer p is accomplished by p but in Modula 2 it is accomplished by p Values can also be represented and displayed differently Hex numbers in C appear as 0x1ae while in Modula 2 they appear as 1AEH Language specific information is built into GDB for some languages allowing you to express operations like the above in th
35. show This command abbreviated i is for describing the state of your program For example you can list the arguments given to your program with info args list the registers currently in use with info registers or list the breakpoints you have set with info breakpoints You can get a complete list of the info sub commands with help info You can assign the result of an expression to an environment variable with set For example you can set the GDB prompt toa sign with set prompt In contrast to info show is for describing the state of GDB itself You can change most of the things you can show by using the related command set for example you can control what number system is used for displays with set radix or simply inquire which is currently in use with show radix To display all the settable parameters and their current values you can use show with no arguments you may also use info set Both commands produce the same display Here are three miscellaneous show subcommands all of which are exceptional in lacking corresponding set commands show version Show what version of GDB is running You should include this information in GDB bug reports If multiple versions of GDB are in use at your site you may need to determine which version of GDB you are running as GDB evolves new commands are introduced and old ones may wither away Also many system vendors ship variant versions of GDB and there are variant versions of
36. value 0x0 number 62 value 0x0 number 63 value 0x0 number 64 value 0xfe00a300 number 65 value 0x29002 number 66 value 0x202f04b5 number 67 value 0xfe0043b0 number 68 value 0xfe00b3e4 number 69 value 0x20002b03 gdb 1 The data read memory command Synopsis data read memory o byte offset address word format word size nr rows nr cols aschar where address An expression specifying the address of the first memory word to be read Complex expressions containing embedded white space should be quoted using the C convention 21 6 GDB MI Data manipulation 325 word format word size nr rows nr cols aschar byte offset The format to be used to print the memory words The notation is the same as for GDB print command see Output formats page 86 The size of each memory word in bytes The number of rows in the output table The number of columns in the output table If present indicates that each row should include an ASCII dump The value of aschar is used as a padding character when a byte is not amember of the printable ASCII character set printable ASCII characters are those whose code is between 32 and 126 inclusively An offset to add to the address before fetching memory This command displays memory contents as a table of nr rows by nr cols wor
37. 29000041 rl 51a800 rp 7 6ce597 x3 7 7 0000 r4 1 r5 7f7f06f4 r6 7 7f06fc r7 7f7f0800 r8 7f7f0800 r9 40006b10 r10 0 r11 40004b78 rra r13 0 r14 0 r15 0 r16 40003fb8 r17 4 30 31 Try two test cases 250 The HP UX Terminal User Interface first first last last 3 gt 32 print_average my_list 33 print_average my_list 34 lt 35 File average c Procedure main gdb la regs gdb la sre gdb la regs gdb foc next Focus set to REGS window gdb fr 0 main at average c 32 gdb pc 0x3524 The default floating point register display is single precision To change the register display to double precision and then back again use the XDB toggle float command toggle fregs The window looks like this 0 7 00649232e 45 first first last last 3 fpsr 0 fpel fpe2 0 fpe3 fpe4 0 fpe5 fpe6 0 fpe7 fr4 0 fr4R fr5 1 0000000000000011 r5R gt 32 print_average my_list 33 print_average my_list 34 35 36 Ree File average c Procedure main gdb la regs gdb la sre gdb la regs gdb foc next Focus set to REGS window gdb fr gdb tf gdb 15 8 Changing the pane size 0x3524 To specify a new height for a pane or to increase or decrease the current height use the winheight command abbreviated winh or wh The syntax is 15 8 Changing the pane size 251 winheight win_name num_lines If you omit win_name the p
38. 4 alignment 1 col_name disp colhdr Disp width 3 alignment 1 col_name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colhdr What body bkpt number 1 type breakpoint disp keep enabled y addr 0x000100d0 func main file hello c line 5 times 0 bkpt number 2 type breakpoint disp keep enabled y addr 0x00010114 func foo file hello c line 13 times 0 gdb Here is an example of the result when there are no breakpoints gdb break list done BreakpointTable nr_ rows 0 nr_ cols 6 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col_name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alignment 1 col_name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colhdr What body gdb The break watch command Synopsis break watch a r Create a watchpoint With the a option it will create an access watchpoint that is a watchpoint that triggers either on a read from or on a write to the memory location With the x option the watchpoint created is a read watchpoint that is it will trigger only when the memory location is accessed for reading Without either of the options the watchpoint created is a
39. 73 When the innermost frame is selected this is a good way to delete a breakpoint where your program just stopped clear function clear Delete any breakpoints set at entry to the function filename function function clear linenum clear Delete any breakpoints set at or within the code filename linenum of the specified line delete breakpoints Delete the breakpoints watchpoints or range catchpoints of the breakpoint ranges specified as arguments If no argument is specified delete all breakpoints GDB asks confirmation unless you have set confirm off You can abbreviate this command as d 5 1 4 Disabling breakpoints Rather than deleting a breakpoint watchpoint or catchpoint you might prefer to disable it This makes the breakpoint inoperative as if it had been deleted but remembers the information on the breakpoint so that you can enable it again later You disable and enable breakpoints watchpoints and catchpoints with the enable and disable commands optionally specifying one or more breakpoint numbers as arguments Use info break or info watch to print a list of breakpoints watchpoints and catchpoints if you do not know which numbers to use A breakpoint watchpoint or catchpoint can have any of four different states of enablement e Enabled The breakpoint stops your program A breakpoint set with the break command starts out in this state e Disabled The breakpoint has no effect on your program 5
40. AEE E E A E A E EE TE 273 M through Parsresreiesi sirier ay vakegsaitencasteasetesyenia caus EER orire e iara aen ierat 274 Q through Serce Betedss srednsayaalie rennin isee iini iii eiei aE NEE r E enEee 275 a BOND Poh fred O A A 6 Fae 275 U through Zirne tides easacn paint EE EE ETER E E AER E 276 SVT OL E ANEETA T eel deiet usd aaebeayinte stan coesadeas ans 277 GDB MI SOP Ora OM Sess tagee soca cole eneee tere rE aaa Eea E E S AEAEE TEE 356 13 List of Examples 14 1 Sample Output for the find command 14 2 14 List of Examples Sample Commands to Print NaT Registers Summary of GDB The purpose of a debugger such as GDB is to allow you to see what is going on inside another program while it executes or what another program was doing at the moment it crashed GDB allows you to do the following e Load the executable along with any required arguments e Stop your program on specified blocks of code e Examine your program when it has stopped running due to an error e Change things in your program so you can experiment with correcting the effects of one bug and go on to learn about another You can use GDB to debug programs written in C C and Fortran For more information refer to the Supported languages page 105 For more information on supported languages refer to the C and C page 106 GDB can be used to debug programs written in Fortran although it may be necessary to refe
41. Configuration Specific Information Breakpoint 2 at 0x40007d0 2 file scope c line 23 from scl gdb b 30 Breakpoint 3 at 0x40007e0 0 file scope c line 30 from scl gdb r Starting program scl Breakpoint 1 main at scope c 13 13 gdb print USED1 100 gdb print USED1 10 110 gdb info macro USED1 Defined at scope c 4 define USED1 100 gdb info macro USED2 The macro USED2 has no definition in the current scope gdb c Continuing Breakpoint 2 main at scope c 23 23 val USED1 USED2 gdb info macro USED1 Defined at scope c 20 define USED1 101 gdb info macro USED2 Defined at scope c 21 define USED2 201 gdb c Continuing Breakpoint 3 main at scope c 30 30 val USED1 gdb info macro USED1 Defined at scope c 28 define USED1 102 gdb info macro USED2 The macro USED2 has no definition in the current scope gdb q The program is running Exit anyway y orn y 14 10 Debugging Memory Problems You can use WDB to nd leaks profile heap usage and detect other heap related errors in HP C HP aC and HP Fortran programs written for HP UX 11 x systems Both 32 bit and 64 bit programs are supported On HP UX 11 x the memory debugging features of WDB work with both single threaded and multi threaded programs that use POSIX threads 14 10 Debugging Memory Problems 157 For more information on memory debugging with WDB see the Debugging Dynamic Memory U
42. HP WDB You can use the environment variable GDB_ROOT to specify an alternate root for GDB If you specify both WDB_ROOT and GDB_ROOT the value for GDB_ROOT is ignored HP WDB supports these environment variables to override the location of different component of HP WDB Defined Variable opt langtools GDB_ROOT GDB_SERVER bin WDB Location opt langtools n a n a lib GDB location WDB_ ROOT GDB_ROOT bin LIBRTC_ SERVER 14 4 HP UX targets 143 librtc sllocation WDB_ ROOT bin opt langtools n a bin None SWDB_ROOT bin GDB SERVER n a opt langtools SWDB_ ROOT 1lib n a SLIBRTC_ SERVER bin A NOTE If you define WDB_ROOT or GDB_ROOT but do not create the correct directory E structure below it the debugger may fail 14 6 Specifying object file directories GDB enables automatic loading of debug information from object modules when an application is compiled with the obj debug option GDB uses the full path name to the object module files and searches the same directories for source files Although this behavior is transparent you can control when and how object files are loaded with three commands objectdir path Specifies a colon separated list of directories in which GDB searches for object files These directories are added to the beginning of the existing objectdir path If you specify a directory that is already in the obj ect dir path the specified directory is moved up in the objectdir path so that it
43. Heap Start 0x40408000 Heap End 0x4041a900 Heap Size 76288 bytes Outstanding Allocations 41558 bytes allocated in 28 blocks No Total bytes Blocks Address Function 0 34567 1 0x40411000 foo 1 4096 1 0x7bd63000 bar 2 1234 1 0x40419710 baz 3 245 8 0x404108b0 boo bere The display shows the currently allocated heap blocks Any blocks that have been allocated and already freed are not listed To look at a specific allocation specify the allocation number with the info heap command gdb info heap 1 4096 bytes at 0x7bd63000 9 86 of all bytes allocated in bar at test c 108 in main at test c 17 in start in SSTARTS 14 10 11 Memory Checking Analysis for User Defined Memory Management Routines Many user applications have their own memory management routines These custom allocator routines are either user defined or sometimes wrappers to the default memory management routines Memory checking features has been extended for user defined memory management routines Memory leak profile of heap memory or memory errors can be obtained for user defined memory management routines Limitations e This feature routes to default memory routines instead of calling user defined memory management routines to obtain memory analysis e This feature is not supported in batch mode and attach mode debugging 14 10 12 Commands to track the change in data segment value The high water mark records the number of
44. However GDB has no provision for frameless functions elsewhere in the stack 6 3 Commands for Examining the Stack The following commands are used for examining the stack frame args Select and print a stack frame With no argument prints the selected stack frame An argument specifies the frame to select It can be a stack frame number or the address of the frame With argument nothing is printed if input is coming from a command file or a user defined command select frame Theselect frame command allows you to move from one stack frame to another without printing the frame This is the silent version of frame 6 4 Backtraces A backtrace is a report of the active stack frames instantiated by the execution of a program It shows one line per frame for all the active frames starting with the currently executing frame frame zero followed by its caller frame one and on up the stack The following commands are used for backtrace backtrace bt backtrace n bt n backtrace n bt n backtrace other thread 72 Examining the Stack Print a backtrace of the entire stack one line per frame for all frames in the stack You can stop the backtrace at any time by typing the system interrupt character normally C c Similar but print only the innermost n frames Similar but print only the outermost n frames Print backtrace of all stack frames for a thread with stack pointer SP and program counter PC This command is useful
45. If you use defaults for nfu you need not type the slash Several commands set convenient defaults for addr n the repeat count The repeat count is a decimal integer and the default is 1 It specifies how much memory counting by units u to display the display format The display format is one of the formats used by print s null terminated string or i machine instruction The default is x hexadecimal initially The default changes each time you use either x or print u the unit size The unit size is any of b Bytes h Halfwords two bytes 2 b cannot be used because these format letters are also used with the x command where b stands for byte see Examining memory page 87 8 5 Examining memory 87 88 w Words four bytes This is the initial default g Giant words eight bytes Each time you specify a unit size with x that size becomes the default unit the next time you use x For the s and i formats the unit size is ignored and is normally not written addr starting display address addr is the address where you want GDB to begin displaying memory The expression need not have a pointer value though it may it is always interpreted as an integer address of a byte of memory Refer to See Expressions page 83 for more information on expressions The default for addr is usually just after the last address examined but several other commands also set the defa
46. Once the ignore count reaches zero GDB resumes checking the condition You could achieve the effect of the ignore count with a condition such as foo lt 0 using a debugger convenience variable that is decremented each time See Convenience variables page 96 Ignore counts apply to breakpoints watchpoints and catchpoints 5 1 6 Breakpoint command lists You can give any breakpoint or watchpoint or catchpoint a series of commands to execute when your program stops due to that breakpoint For example you might want to print the values of certain expressions or enable other breakpoints commands bnum Specify a list of commands for breakpoint number command list end bnum The commands themselves appear on the following lines Type a line containing just end to terminate the commands To remove all commands from a breakpoint type commands and follow it immediately with end that is give no commands With no bnum argument commands refers to the last breakpoint watchpoint or catchpoint set not to the breakpoint most recently encountered Pressing RET as a means of repeating the last GDB command is disabled within a command list 5 1 Breakpoints 61 You can use breakpoint commands to start your program up again Simply use the continue command or step or any other command that resumes execution Any other commands in the command list after a command that resumes execution are ignored This is b
47. RDI targets respectively Brian Fox is the author of the readline libraries providing command line editing and command history Andrew Beers of SUNY Buffalo wrote the language switching code the Modula 2 support and contributed the Languages chapter of this manual Fred Fish wrote most of the support for Unix System Vr4 He also enhanced the command completion support to cover C overloaded symbols Hitachi America Ltd sponsored the support for H8 300 H8 500 and Super H processors NEC sponsored the support for the v850 Vr4xxx and Vr5xxx processors Mitsubishi sponsored the support for D10V D30V and M32R D processors Toshiba sponsored the support for the TX39 Mips processor Matsushita sponsored the support for the MN10200 and MN10300 processors Fujitsu sponsored the support for SPARClite and FR30 processors Kung Hsu Je Law and Rick Sladkey added support for hardware watchpoints Michael Snyder added support for tracepoints Stu Grossman wrote gdbserver Jim Kingdon Peter Schauer Ian Taylor and Stu Grossman made nearly innumerable bug fixes and cleanups throughout GDB The following people at the Hewlett Packard Company contributed support for the PA RISC 2 0 architecture HP UX 10 20 10 30 and 11 x narrow mode HP s implementation of kernel threads HP s aC compiler and the terminal user interface Ben Krepp Richard Title John Bishop Susan Macchia Kathy Mann Satish Pai India Paul Steve Rehrauer and Elen
48. Shared Libraries As Private The mapshared option suppresses mapping all shared libraries in a process private This option enables new functions in the dynamic loader patch PHSSS_33110 or later to designate individual shared libraries for debugging By default HP WDB instructs the shared library dynamic loader d1d s1 5 to map shared libraries in a process private regardless of whether the chat r command is run for a particular shlib with dbg or not The mapshared option is used to save virtual memory for debugging applications with large amounts of code in shared libraries on machines with simultaneous debug sessions The chatr dbg option and the HP DLDOPTS environment variable are used to identify shared libraries for debugging The mapshared option ensures that the text segments of all other shared libraries is shared across the system The shared libraries are not mapped private and cannot have breakpoints set in them The set mapshared on command can be used to change modes from the gdb prompt gdb set mapshared on The set mapshared off command can be used to load shared libraries after the current point is mapped private gdb set mapshared off 212 HP UX Configuration Specific Information The mapshared option is implemented on both PA RISC and Itanium platforms in HP WDB 5 2 This option is provided in the WDB GUI and HP WDB The default behavior does not change if the mapshared option for all shared libraries in p
49. The operator aids in the debugging of dynamic arrays formed with pointers and a memory allocation function See Expressions page 83 9 4 1 7 GDB features for C Some GDB commands are particularly useful with C and some are designed specifically for use with C Here is a summary breakpoint menus rbreak regex catch throw catch catch ptype typename set print demangle show print demangle set print asm demangle show print asm demangle set print object show print object set print vtbl show print vtbl set overload resolution on When you want a breakpoint in a function whose name is overloaded GDB breakpoint menus help you specify which function definition you want See Breakpoint menus page 62 Setting breakpoints using regular expressions is helpful for setting breakpoints on overloaded functions that are not members of any special classes See Setting breakpoints page 52 Debug C exception handling using these commands See Setting catchpoints page 56 Print inheritance relationships as well as other information for type typename See Chapter 10 page 115 Control whether C symbols display in their source form both when displaying code as C source and when displaying disassemblies See Print settings page 90 Choose whether to print derived actual or declared types of objects See Print settings page 90 Control the format for printing vi
50. Thread 205 14 17 gdb i ep Local execution path table for main 0 0x4000a80 2 execpath c 10 gdb i gep Global execution path table GO 0x4000a80 2 main execpath c 10 gdb n 15 ECC gdb i ep Local execution path table for main O 0x4000a80 2 execpath c 10 gdb i gep Global execution path table GO 0x4000a80 2 main execpath c 10 gdb n 16 printf Value of c greater than 0 n gdb n Value of c greater than 0 18 printf All condition checking done n gdb i ep Local execution path table for main O 0x4000a80 2 execpath c 10 2 0x4000bd0 2 execpath c 16 gdb i ep summary Summary for local execution path table for main Size 3 Total Number of Branch Paths in Current Function Effective entries 2 Number of Branches executed till this instant Current entry 2 Last executed branch number gdb i gep Global execution path table GO 0x4000a80 2 main execpath c 10 G1 0x4000bd0 2 main execpath c 16 gdb i gep summary Summary for global execution path table Size 65536 Maximum execution path entries to be stored Effective entries 2 Number of global execution path entries Current entry 1 The last Global Path ID executed gdb Command to Unwind Beyond 10000 Frames The number of frames to be unwound by default is set to 10000 so that HP WDB does not run out of memory To enable unwinding beyond 10000 frames HP WDB supports the set unwind all frames command at t
51. a 273 16 89 60 M through Piscsinosrrosas eieiei ire e A E A A S 274 16 89 7 Q through S eree eea aa E Aea E Sae Ena OEN EEEE EEA E 275 ESS Tr E I E E A S E N N E 275 16 8 9 U through Z aiino eE ons a oita eea NANESE eE EA ASEE TENER TEs 276 LG SLO Sy MBO lS rsrsrs sea EE A AEE A E TEE E AA ia eaaa 277 1 Controlling GDB itu iisinii annas niran aa ao SEA Ea A E SA ETRA EAER ESR 281 17 1 Setting the GDB Prompt sereme rea a eiia a EET ERAEN EEEE 281 17 2 Setting Command Editing Options in GDB s sssssessserssrsessseissessrereesserssrsresserssesees 281 17 3 Setting Command History Feature in GDB ssssessessserssssssseessisssereessersresresseessesees 281 174 Setting the GDP Scree SIAR cater tetas cases teehee Ure aeai aegis a iinta 283 17 5 Supported Number Formats neesii ienesis eiiie aesti Eaei ys eiie gt 283 17 6 Optional warnings and messages ss sessesssersetseesseississeseisstsseereesseenresrerserssesees 284 17 7 Optional messages about internal happeningS ccccccecesecsseeseeseeeeeesseneesseeseees 285 18 Canned Sequences of Comimandsicsasissssissssuesesonisssancsisocsesonys saduseSesdovonsanpdaveedd dsompsaaactebersOonvaats 287 18 1 User defined commands eniste a ei e ENEA ES AE NaN S 287 18 2 User defined command hooks cccecccccccccecescesseeececeeecesceueeescecceeseaeaueeseeceeeeeaeaaes 288 18 3 Comand MES Senin A r E E AA E a ASE 289 18 4 Commands for controlled Output ccsscss cases ceovacce
52. a blow by blow account Changes much prior to version 2 0 are lost in the mists of time Free Software 15 16 Plea Additions to this section are particularly welcome If you or your friends or enemies to be evenhanded have been unfairly omitted from this list we would like to add your names So that they may not regard their many labors as thankless we particularly thank those who shepherded GDB through major releases Andrew Cagney release 5 0 Jim Blandy release 4 18 Jason Molenda release 4 17 Stan Shebs release 4 14 Fred Fish releases 4 16 4 15 4 13 4 12 4 11 4 10 and 4 9 Stu Grossman and John Gilmore releases 4 8 4 7 4 6 4 5 and 4 4 John Gilmore releases 4 3 4 2 4 1 4 0 and 3 9 Jim Kingdon releases 3 5 3 4 and 3 3 and Randy Smith releases 3 2 3 1 and 3 0 Richard Stallman assisted at various times by Peter TerMaat Chris Hanson and Richard Mlynarik handled releases through 2 8 Michael Tiemann is the author of most of the GNU C support in GDB with significant additional contributions from Per Bothner James Clark wrote the GNU C demangler Early work on C was by Peter TerMaat who also did much general update work leading to release 3 0 GDB 4 uses the BFD subroutine library to examine multiple object file formats BFD was a joint project of David V Henkel Wallace Rich Pixley Steve Chamberlain and John Gilmore David Johnson wrote the original COFF support Pace Williso
53. a core file generated when running a 64 bit Java application on PA RISC using opt javal 4 bin java gdb opt javal 4 bin PA_RISC2 0W java core java When debugging a core file it is good practice to rename the file from core to another name to avoid accidentally overwriting it If the Java and system libraries used by the failed application reside in non standard locations then the GDB_SHLIB_ PATH environment variable must be set to specify the location of the libraries 14 25 1 4 Java attach mode debugging support HP WDB supports java debugging in attach mode also GDB_JAVA_UNWINDLIB environment variable must be set to the path name of the Java unwind library From gdb version 5 6 and later versions GDB JAVA UNWINDLIB environment variable need not be set to the path name of the Java unwind library HP WDB uses the libjunwind s1 specified by the Java Virtual Machine The following examples illustrate how to invoke gdb on a hung process 1 Determine the process id ps u userl grep java 23989 pts 9 8 52 java 220 HP UX Configuration Specific Information 2 Attach gdb to the running process gdb p 23989 HP gdb 5 0 for HP Itanium 32 or 64 bit and target HP UX 11 2x Copyright 1986 2001 Free Software Foundation Inc Hewlett Packard Wildebeest 5 0 based on GDB is covered by the GNU General Public License Type show copying to see the con ditions to change it and or distribute copies Type show warranty for warrant
54. a variable object var delete delete the variable object and its children var set format set the display format of this variable var show format show the display format of this variable var info num children tells how many children this object has var list children return a list of the object children var info type show the type of this variable object var info expression print what this variable object represents var show attributes is this variable editable does it exist here var evaluate expression get the value of this variable var assign set the value of this variable var update update the variable and its children In the next subsection we describe each operation in detail and suggest how it can be used Description and use of operations on variable objects The var create command Synopsis var create name frame addr expression This operation creates a variable object which allows the monitoring of a variable the result of an expression a memory cell or a CPU register The name parameter is the string by which the object can be referenced It must be unique If is specified the varobj system will generate a string varNNNNNN automatically It will be unique provided that one does not specify name on that format The command fails if a duplicate name is found 356 The GDB MI Interface The frame under which the expression should be
55. addr 0x00001510 data 128 gdb Read thirty two bytes of memory starting at bytes 16 and format as eight rows of four columns Include a string encoding with x used as the non printable character gdb 4 data read memory bytes 16 x 184x 4 done addr 0x000013a0 nr bytes 32 total bytes 32 next row 0x000013c0 prev row 0x0000139c next page 0x000013c0 prev page 0x00001380 memory addr 0x000013a0 data 0x10 0x11 0x12 0x13 ascii xxxx addr 0x000013a4 data 0x14 0x15 0x16 0x17 ascii xxxx addr 0x000013a8 data 0x18 0x19 0xla 0x1b ascii xxxx addr 0x000013ac data 0x1lc 0x1d 0xle 0x1f ascii xxxx addr 0x000013b0 data 0x20 0x21 0x22 0x23 ascii addr 0x000013b4 data 0x24 0x25 0x26 0x27 ascii S amp addr 0x000013b8 data 0x28 0x29 0x2a 0x2b ascii addr 0x000013be data 0x2c 0x2d 0x2e 0x2f ascii gdb The display delete command Synopsis display delete number Delete the display number GDB command The corresponding GDB command is delete display Example N A The display disable Command Synopsis display disable number Disable display number GDB command The corresponding GDB command is disable display Example N A 21 6 GDB MI Data manipulation 327 The display enable command Synopsis display enable number Enable displa
56. be easy to confuse Emacs about the location of the source files in which case the auxiliary display buffer does not appear to show your source GDB can nd programs by searching your environment s PATH variable so the GDB input and output session proceeds normally but Emacs does not get enough information back from GDB to locate the source files in this situation To avoid this problem either start GDB mode from the directory where your program resides or specify an absolute file name when prompted for the M x gdb argument A similar confusion can result if you use the GDB file command to switch to debugging a program in some other location from an existing GDB buffer in Emacs By default M x gdb calls the program called gdb If you need to call GDB by a different name for example if you keep several configurations around with different names you can set the Emacs variable gdb command name for example setq gdb command name mygdb preceded by M or ESC or typed in the scratch buffer or in your emacs file makes Emacs call the program named mygdb instead 293 In the GDB T O buffer you can use these special Emacs commands in addition to the standard Shell mode commands C h m M s M n M i M x gdb nexti C c C f M c M u M d C x amp Describe the features of Emacs GDB Mode Execute to another source line like the GDB step command also update the display window to show the current file a
57. can use in GDB expressions regardless of your programming language Casts are supported in all languages not just in C because it is so useful to cast a number into a pointer in order to examine a structure at that address in memory GDB supports these operators in addition to those common to programming languages is a binary operator for treating parts of memory as arrays Refer to See Artificial arrays page 85 for more information 8 1 Expressions 83 allows you to specify a variable in terms of the file or function where it is defined See Program variables page 84 type addr Refers to an object of type type stored at address addr in memory addr may be any expression whose value is an integer or pointer but parentheses are required around binary operators just as in a cast This construct is allowed regardless of what kind of data is normally supposed to reside at addr 8 2 Program variables 84 The most common kind of expression to use is the name of a variable in your program Variables in expressions are understood in the selected stack frame see Selecting a frame page 73 they must be either e global or file static or e visible according to the scope rules of the programming language from the point of execution in that frame This means that in the function foo a int a bar a int b test bar b you can examine and use the variable a wheneve
58. can use the detach command to release it from GDB control The process continues its execution after being detached After the detach command that process and GDB become completely independent once more and you are ready to attach another process or start one with run detach does not repeat if you press RET again after executing the command If you exit GDB or use the run command while you have an attached process you kill that process By default GDB asks for confirmation if you try to do either of these things you can control whether or not you need to confirm by using the set confirm command see Optional warnings and messages page 284 A NOTE When GDB attaches to a running program you may get a message saying Attaching to process nnnnn failed The most likely cause for this message is that you have attached to a process that was started across an NFS mount Versions of the HP UX kernel before 11 x have a restriction that prevents a debugger from attaching to a process started from an NFS mount unless the mount was made non interruptible with the nointr flag see mount 1 4 8 Killing the child process Following command is used to kill the child process kill Kill the child process in which your program is running under GDB The kill command is useful if you wish to debug a core dump instead of a running process GDB ignores any core dump file while your program is running 4 8 Killing the child process 45
59. command This is done with the define command User commands may accept up to 10 arguments separated by whitespace Arguments are accessed within the user command via arg0 Sarg9 The following example illustrates the use of canned sequence of commands define adder print arg0 Sargl Sarg2 To execute the command use adder 1 2 3 This defines the command adder which prints the sum of its three arguments Note the arguments are text substitutions so they may reference variables use complex expressions or even perform further functions calls The following constructs can be used to create canned sequence of commands define commandname Define a command named commandname If there is already a command by that name you are asked to confirm that you want to redefine it The definition of the command is made up of other GDB command lines which are given following the define command The end of these commands is marked by a line containing end if Takes a single argument which is an expression to evaluate It is followed by a series of commands that are executed only if the expression is true nonzero The if clause can be followed by an optional else clause You can add a list of commands to the else clause which get executed only if the expression is false while The syntax is similar to if the command takes a single argument which is an expression to evaluate and must be followed by the commands to execute one per l
60. command is used to avoid single stepping through a loop more than once It is like the next command except that when until encounters a jump it automatically continues execution until the program counter is greater than the address of the jump This means that when you reach the end of a loop after single stepping though it until makes your program continue execution until it exits the loop In contrast a next command at the end of a loop simply steps back to the beginning of the loop which forces you to step through the next iteration until always stops your program if it attempts to exit the current stack frame until may produce somewhat counterintuitive results if the order of machine code does not match the order of the source lines For example in the following excerpt from a debugging session the f frame command shows that execution is stopped at line 206 yet when we use until we get to line 195 gdb 0 main argc 4 argv Oxf7fffae8 at m4 c 206 206 expand input gdb until 195 for argc gt 0 NEXTARG This happened because for execution efficiency the compiler had generated code for the loop closure test at the end rather than the start of the loop even though the test in a C for loop is written before the body of the loop The until command appeared to step back to the beginning of the loop when it advanced to this expression however it has not really gone to an earlier statement not i
61. conventions for identifying threads The thread apply command allows you to apply acommand to one or more threads Specify the numbers of the threads that you want affected with the command argument threadno t hreadno is the internal GDB thread number as shown in the first field of the info threads display To apply a command to all threads use thread apply all args Whenever GDB stops your program due to a breakpoint or a signal it automatically selects the thread where that breakpoint or signal happened GDB alerts you to the context switch with a message of the form Switching to systag to identify the thread See Stopping and starting multi thread programs page 69 for more information about how GDB behaves when you stop and start programs with multiple threads See Killing the child process page 45 for information about watchpoints in programs with multiple threads A NOTE On HP UX 11 x debugging a multi thread process can cause a deadlock if the process is waiting for an NFS server response A thread can be stopped while asleep in this state and NFS holds a lock on the rode while asleep To prevent the thread from being interrupted while holding the rnode lock make the NFS mount non interruptible with the nointr flag See mount 1 4 10 Debugging programs with multiple processes On most systems GDB has no special support for debugging programs which create additional processes using t
62. corrupted an under flow or over flow must have occurred and WDB reports the problem This option increases the program s memory requirements Scrambles a memory block and overwrites it with a specific pattern when it is allocated or deallocated This change to the memory contents increases the chance that erroneous behaviors such as attempting to access space that is freed or depending on initial values of malloc blocks cause the program to fail Displays a list of all the dangling pointers and dangling blocks that are potential sources of memory corruption may have false positives Checks for corruption in the currently allocated heap blocks In addition it lists the potential in block corruptions in all the freed blocks Collects a stack trace only when the size of the leak exceeds the number of bytes you specify for this value Larger values improve run time performance The default value is zero 0 bytes Controls the depth of the call stack collected Larger values increase run time The default value is four 4 stack frames Sets the Header guard for each block of the allocated memory The default number of bytes for the footer is 16 bytes if this option is not used If the user specifies a value less than 16 for the number of bytes the debugger ignores it and takes the default of 16 bytes If the user specifies more than 16 bytes then the debugger considers the largest and closest 16 byte integral from the use
63. count parameter gdb find 1 amp int8_search_buf 0 sizeof int8_search_buf a a a where 1 Specifies the find command to display only one matching pattern amp int8_search_buf 0 Specifies the starting address sizeof int8_search_buf Specifies the ending address a al a Specifies the pattern expr1 expr2 expr3 Using the size char parameter gdb find b amp int8 search buf 0 amp int8 search buf 0 sizeof int8 search buf Ox61 Ox61 Ox61 Ox61 where b Specifies that the size of the pattern is 8 bits amp int8 search buf 0 Specifies the starting address amp int8 search buf 0 Specifies the ending address sizeof int8 search buf 0x61 0x61 0x61 0x61 Specifies the pattern expr1 expr2 expr3 exp4 14 14 Command to Search for a Pattern in the Memory Address Space 199 A NOTE Following are different ways of representing the size char and max count parameters 1b b1 b 1 1 b where 1 Specifies that find must display 1 matching pattern b Specifies that the size of the pattern is 8 bits 14 15 Debugging Core Files 14 15 1 Generating core files with packcore unpackcore getcore The contents of a core file can be viewed only on a system which has all the shared libraries that were in use on the system on which the core file was generated If you want to view the content of the core file on a system which does not have the shared libraries you
64. current source line the printed value will be the immediately previous or immediately later value for the variable Backtrace commands backtrace can be used to display the current nest of function calls including calls that are inlined When stopped within the code for an inlined call the parameters and the local variables of the inlined routine are not reported or available The disassem command does not work for functions that have no code because all calls to these functions are inlined or these functions are not called at all HP WDB 5 7 14 29 Debugging optimized code 229 and later versions provide support to prevent the debugged program from stopping at instructions that are predicated false The program execution can be stopped by a software breakpoint a hardware breakpoint or an asynchronous signal In the case of optimizations such as if conversion the predicated false instructions indicate that an alternate source path is executed Hence stopping the program at a predicated false instruction results in the misleading conclusion that the path corresponding to the predicated false instruction is executed To prevent this ambiguity HP WDB does not stop at predicated false instructions The predicated false instructions are equated to NOPs No OPeration because these instructions do not modify the processor state The exception to this rule is the use of certain instructions such as wtop wexit and frcpa which modify the pro
65. debugger sm sm with xdb set height 0 Suspend more turn o pagination ss file No equivalent Save breakpoint macro assertion state te No equivalent Toggle case sensitivity in searches 16 3 XDB data formats and HP WDB equivalents The format of the print command is different in XDB and GDB XDB p expr fmt GDB p fmt expr Use the set print pretty command to obtain a structured display similar to the default XDB display The following table lists the XDB and equivalent WDB commands for setting data display formats Table 16 16 Data format commands XDB Command WDB Equivalent Byte in decimal B 1 d Byte in decimal c c Character Cc 1 c Wide character 266 XDB to WDB Transition Guide Table 16 16 Data format commands continued XDB Command WDB Equivalent Meaning d d Decimal integer D 1 d Long decimal integer e No equivalent e Floating point notation as float E 1 No equivalent e Foating point notation as double f No equivalent f floating point notation as float F 1 No equivalent f floating point notation as double g f g floating point notation as float G 1 f g floating point notation as double i Use x i command Machine instruction disassembly k No equivalent Formatted structure display K 1 No equivalent Formatted structure display with base classes n print Normal default format based on t
66. detailed information on the specified heap allocation including the allocation call stack Displays all current settings for memory checking This command starts incremental heap growth profile All allocations prior to the execution of this command are ignored from report If incremental heap growth profile is already on executing this command will reset the counters and start a fresh collection Interval is specified in seconds This allows user to specify the number of intervals GDB should collect the incremental heap growth The default value is 100 Every repeat of the interval tracks heap allocation during that interval Example lt gdb gt set heap check interval 10 lt gdb gt set heap check repeat 100 Here WDB will create 100 incremental apart heap profiles which are 10 seconds apart GDB stores incremental heap growth data in an internal file During one session data is appended to this file If the session is very long it is possible that this file may become very large This command discards the data existing in the file and creates a new data file Once this command is executed the user cannot see the old data This command creates the report of heap growth The data for each interval has the start and end time of the interval If file name is mentioned a detailed report is written in the file Controls WDB memory leak checking Displays a leak report listing information such as the leaks size of
67. enter something else if breakpoints does not look like the command you expected If you were sure you wanted info breakpoints in the first place you might as well just type RET immediately after info bre to exploit command abbreviations rather than command completion If there is more than one possibility for the next word when you press TAB GDB sounds a bell You can either supply more characters and try again or just press TAB a second time GDB displays all the possible completions for that word For example you might want to set a breakpoint on a subroutine whose name begins with make_ but when you type b make_TAB GDB just sounds the bell Typing TAB again displays all the function names in your program that begin with those characters for example gdb b make_TAB GDB sounds bell press TAB again to see make_a_section_ from file make_environ make_abs_section make_function_type make_blockvector make_pointer_type make_cleanup make_reference_type make_command make_symbol_completion_list gdb b make_ After displaying the available possibilities GDB copies your partial input b make_ in the example so you can finish the command If you just want to see the list of alternatives in the first place you can press M rather than pressing TAB twice M means META You can type this either by holding down a key designated as the META shift on your keyboard if there is one while typing or as ESC followed b
68. evaluated can be specified by frame addr A indicates that the current frame should be used expressionis any expression valid on the current language set must not begin with a or one of the following e addr where addr is the address of a memory cell e addr addr amemory address range TBD e Sregname a CPU register name Result This operation returns the name number of children and the type of the object created Type is returned as a string as the ones generated by the GDB CLI name name numchild N type type The var delete command Synopsis var delete name Deletes a previously created variable object and all of its children Returns an error if the object name is not found The var set format command Synopsis var set format name format spec Sets the output format for the value of the object name to be format spec The syntax for the format spec is as follows format spec binary decimal hexadecimal octal natural The var show format command Synopsis var show format name Returns the format used to display the value of the object name format format spec The var info num children command Synopsis var info num children name 21 14 GDB MI variable objects 357 Returns the number of children of a variable object name numchild n The var list children command Synopsis var list children name Returns a list of the children of the specified variable obje
69. following ANSI C interface addr is where the exception identifier is stored id is the exception identifier void raise exception void addr void id To make the debugger catch all exceptions before any stack unwinding takes place set abreakpointon raise exception see Breakpoints page 51 With a conditional breakpoint see Break conditions page 59 that depends on the value of id you can stop your program when a specific exception is raised You can use multiple conditional breakpoints to stop your program when any of a number of exceptions are raised 5 1 Breakpoints 57 5 1 3 Deleting breakpoints It is often necessary to eliminate a breakpoint watchpoint or catchpoint once it has done its job and you no longer want your program to stop there This is called deleting the breakpoint A breakpoint that has been deleted no longer exists it is forgotten With the clear command you can delete breakpoints according to where they are in your program With the delete command you can delete individual breakpoints watchpoints or catchpoints by specifying their breakpoint numbers It is not necessary to delete a breakpoint to proceed past it GDB automatically ignores breakpoints on the first instruction to be executed when you continue execution without changing the execution address clear Delete any breakpoints at the next instruction to be executed in the selected stack frame see Selecting a frame page
70. for debugging C programs running under Linux Runtime Environment Support for stop in at dbx commands Support for GNU GDB logging commands Support for persistent display of expressions across re runs The user does not need to re initiate the display settings for every run Viewing wide character and wide character strings of type wchar_t using the type print command Support for debugging of executables with method and expressions involving covariant return types Support for commands catch throw catch catch and info catch for debugging exception handlers in C on Integrity systems with the aCC compiler A 06 00 and later Support for the steplast command for C and C However steplast command is not supported Support for dumping an array into an ASCII file Support for the Fortran array slices Source level debugging of Fortran applications that contain nested routines Support for making command line calls in a stripped executable Support for a terminal user interface that provides view of source while debugging at the WDB command line support for debugging 32 bit and 64 bit PA RISC programs as well as 64 bit Itanium programs Support for assembly level debugging Support for a subset of xdb commands enabled with xdb mode Support for Java C aCC stack unwinding with Java SDK version 1 3 1 02 or later for HP UX Visual Interface for HP WDB tui mode supports output logging Command line calls for 64 bit PA R
71. functions displayed in the stack trace in a non debug optimized executable When GDB has no debug information it does not know where the arguments are located or even the type of the arguments GDB cannot infer this in an optimized non debug executable However for integer arguments you can nd the first few parameters for the top of stack frame by looking at the registers On PA RISC systems the first parameter will be in 726 the second in 725 and so on On IPF systems the first few parameters will be in 9732 and gr33 226 HP UX Configuration Specific Information 14 29 Debugging optimized code HP WDB supports debugging of optimized code compiled with both g and O for HP aC HP ANSI C and HP WDB for HP Itanium The following commands evaluate the name of a function and hence are affected by the optimization level of the program being debugged in particular due to inlining e break e call e clear e disassem e list The following commands evaluate an expression referring to variables in the user pro gram and hence are affected by the optimization level of the program being debugged break call cond e jump return e print set lt var gt e watch e whatis x A NOTE The break and call commands involve evaluation of both the name of a function and an expression The following commands are also affected by the optimization level of the program being debugged e backtrace e display
72. gdb Once started GDB reads commands from the terminal until you tell it to exit You can also run gdb with a variety of arguments and options to specify more of your debugging environment at the outset The command line options described here are designed to cover a variety of situations in some environments some of these options may effectively be unavailable The most usual way to start GDB is with one argument specifying an executable program gdb program You can also start with both an executable program and a core file specified gdb program core You can instead specify a process ID as a second argument if you want to debug a running process gdb program 1234 would attach GDB to process 1234 unless you also have a file named 1234 GDB does check for a core file first Taking advantage of the second command line argument requires a fairly complete operating system when you use GDB as a remote debugger attached to a bare board there may not be any notion of process and there is often no way to get a core dump GDB will warn you if it is unable to attach or to read core dumps You can run gdb without printing the front material which describes GDB s non warranty by specifying silent gdb silent You can further control how GDB starts up by using command line options GDB itself can remind you of the options available Type gdb help to display all available options and briefly describe
73. handle numberstop handle number nostop Meaning List signal handling Toggle stop flag for signal number z number i z number i with xdb handle numbernopass handle number pass Toggle ignore flag for signal number z number r z number r with xdb handle number print handle number noprint Toggle report flag for signal number z number Q 16 2 10 Miscellaneous commands z number Q with xdb handle number noprint Do not print the new state of the signal Some of the additional XDB and the equivalent WDB commands are discussed below Table 16 15 Miscellaneous commands XDB Command WDB Equivalent Meaning Return Return Repeat previous command Return Repeat previous command No equivalent one command per Separate commands in command line in command list list 16 2 Overall breakpoint commands 265 Table 16 15 Miscellaneous commands continued XDB Command WDB Equivalent Meaning cmd line cmd line with xdb she Invoke a shell cmd line cmd list commands number end Execute command list group commands Control C Control C Interrupt the program text text A comment am am with xdb set height Activate more turn on pagination num f printf style fmt No equivalent Set address printing format h h Help M t c expr No equivalent Print object or corefile map expr q q Quit
74. handler caller signal handler caller string where signal handler caller stringis text designed to convey to the user that this frame is associated with whatever mechanism is used by this operating system to call a signal handler it is the frame which calls the signal handler not the frame for the signal handler itself e A normal frame This can optionally depending on whether this is thought of as interesting information for the user to see begin with zZ zframe address address Z Zframe address end separator string where address is the address executing in the frame the same address as in the rame begin annotation but printed in a form which is intended for user consumption lin particular the syntax varies depending on the language and separator string is a string intended to separate this address from what follows for the user s benefit Then comes 77 frame function name function name 7 Zframe args arguments where function name is the name of the function executing in the frame or if not known and arguments are the arguments to the frame with parentheses around them each argument is annotated individually as well see Values page 298 If source information is available a reference to it is then printed Z Zframe source begin source intro string 7 Zframe source file filename 77 frame source file end 77 frame source line line number 77 frame sourc
75. have to set the environment variables GDB_SHLIB_ PATHorGDB SHLIB_ ROOT to make it search for the desired libraries The commands packcore unpackcore and core simplify the process of examining the contents of a core file on a system other than the one in which it was generated The packcore command is used on the system which generated the core file When you are examining the core file on the original system you can execute packcore to make a packcore tar Z file This is a compressed tar file which contains the core file the executable and all the shared libraries that were used by the program when it generated the core file The core file is removed after it is added to the packcore tar Z file The packcore command has one optional argument basename which can be used instead of packcore to make packcore tar Z The packcore tar Z file can be copied to a different system and the gdb command unpackcore unpacks the packcore tar Z file in the current directory creating a new packcore directory After unpacking the packcore file the unpackcore command invokes getcore to load the executable and the core file from the packcore directory and sets GDB_SHLIB_PATH to the modules directory in the packcore directory The modules directory holds all of the shared libraries that were used when the core file was generated The unpackcore command has two optional arguments The first defaults to packcore tar Z and is the name of the packcore file to b
76. in cases where the debugger does not support a user thread package fully The names where and info stack abbreviated info s are additional aliases for backtrace Each line in the backtrace shows the frame number and the function name The program counter value is also shown unless you use set print address off The backtrace also shows the source file name and line number as well as the arguments to the function The program counter value is omitted if it is at the beginning of the code for that line number Here is an example of a backtrace It was made with the command bt 3 so it shows the innermost three frames 0 m4_traceon obs 0x24eb0 argc 1 argv 0x2b8c8 at builtin c 993 1 Ox6e38 in expand macro sym 0x2b600 at macro c 242 2 0x6840 in expand_token obs 0x0 t 177664 td 0xf7fffb08 at macro c 71 More stack frames follow The display for frame zero does not begin with a program counter value indicating that your program has stopped at the beginning of the code for line 993 of builtin c 6 5 Selecting a frame Most commands for examining the stack and other data in your program work on whichever stack frame is selected at the moment The following commands are used for selecting a stack frame all of them finish by printing a brief description of the stack frame selected frame n f n Select frame number n Recall that frame zero is the innermost currently executing frame frame one is the frame that called the
77. in separate directories configure writes configuration specific files in the current directory but arranges for them to use the source in the directory dirname configure creates directories under the working directory in parallel to the source directories below dirname 368 Installing GDB norecursion Configure only the directory level where configure is executed do not propagate configuration to subdirectories target target Configure GDB for cross debugging programs running on the specified target Without this option GDB is configured to debug programs that run on the same machine host as GDB itself There is no convenient way to generate a list of all available targets host Configure GDB to run on the specified host There is no convenient way to generate a list of all available hosts There are many other options available as well but they are generally needed for special purposes only A 3 configure options 369
78. issue a command to GDB without affecting certain aspects of the state which is seen by users prefix it with server This means that this command will not affect the 20 1 What is an annotation 297 command history nor will it affect GDB s notion of which command to repeat if RET is pressed on a line by itself The server prefix does not affect the recording of values into the value history to print a value without recording it into the value history use the output command instead of the print command 20 3 Values When a value is printed in various contexts GDB uses annotations to delimit the value from the surrounding text If a value is printed using print and added to the value history the annotation looks like Z Zvalue history begin history number value flags history string Z Zvalue history value the value Z Zvalue history end where history number is the number it is getting in the value history history stringisa string suchas 5 which introduces the value to the user the value is the output corresponding to the value itself and value flags is for a value which can be dereferenced and for a value which cannot If the value is not added to the value history it is an invalid float or it is printed with the output command the annotation is similar Z Zvalue begin value flags the value Z Zvalue end When GDB prints an argument to a function for example in the output from the
79. language Display the current working language This is the language you can use with commands such as print to build and compute expressions that may involve variables in your program info frame Display the source language for this frame This language becomes the working language if you use an identifier from this frame See Information about a frame page 74 to identify the other information listed here info source Display the source language of this source file Refer to See Chapter 10 page 115 to identify the other information listed here In unusual circumstances you may have source files with extensions not in the standard list You can then set the extension associated with a language explicitly set extension language ext Set source files with extension ext to be language assumed to be in the source language language However this is not valid on Unix systems info extensions List all the filename extensions and the associated languages Not valid on Unix systems 9 3 Type and range checking Some languages are designed to guard you against making seemingly common errors through a series of compile and run time checks These include checking the type of arguments to functions and operators and making sure mathematical overflows are caught at run time Checks such as these help to ensure the correctness of the program once it has been compiled by eliminating type mismatches and providing active checks for range er
80. names see Registers page 98 Value history references in contrast are numbers preceded by See Value history page 95 You can save a value in a convenience variable with an assignment expression just as you would set a variable in your program For example set foo object_ptr would save in foo the value contained in the object pointed to by object _ptr Using a convenience variable for the first time creates it but its value is void until you assign a new value You can alter the value with another assignment at any time Convenience variables have no fixed types You can assign a convenience variable any type of value including structures and arrays even if that variable already has a value of a different type The convenience variable when used as an expression has the type of its current value show convenience Print a list of convenience variables used so far and their values Abbreviated show conv A convenient variable can be used as a counter to be incremented or a pointer to be advanced For example to print a field from successive elements of an array of structures set Si 0 print bar i gt contents Repeat that command by typing RET Some convenience variables are created automatically by GDB and assigned values _ The variable _ is automatically set by the x command to the last address examined see Examining memory page 87 Other commands which provide a default addr
81. new function The old breakpoint is still valid e Ifthe number of lines of the modified file is different from that of the original file the placement of breakpoints may not be correct e When the program resumes the program counter is moved to the beginning of the same line in the modified function The program counter may be at the wrong line 14 7 3 Using Fix and Continue When WDB recompiles a fixed source file it uses the same compiler and the same options that were used to create the original executable If the compiler generates any syntax errors or it encounters any of the restrictions WDB does not patch the changes into the executable image being debugged After you successfully recompile the changes WDB uses the fixed version of the code when you use any of the execution commands such as step run or continue When you use the edit command WDB then monitors any edited source files for additional changes After you enter the initial f ix command WDB checks for additional saved changes to a source file each time you enter a program execution command If a saved source file has been changed WDB asks if you want to fix the changed source allowing you to apply repeated fixes without explicitly entering the fix command The Fix and Continue facility enables you to make the following changes e Change existing function definitions e Disable reenable save and delete redefinitions e Adding global and file static variables
82. of GDB apply to both languages Whenever this is the case we discuss those languages together The C debugging facilities are jointly implemented by the C compiler and GDB Therefore to debug your C code effectively you must compile your C programs with a supported C compiler such as GNU g or the HP ANSI C compiler aCC For best results when using GNU C use the stabs debugging format You can select that format explicitly with the g command line options gstabs or gstabs Refer to section Options for Debugging Your Program or GNU CC in Using GNU CC for more information 9 4 1 1 C and C operators Operators must be defined on values of specific types For instance is defined on numbers but not on structures Operators are often defined on groups of types For the purposes of C and C the following definitions hold e Integral types include int with any of its storage class specifiers char enum and for C bool e Floating point types include float double and long double if supported by the target platform e Pointer types include all types defined as type e Scalar types include all of the above The following operators are supported They are listed here in order of increasing precedence The comma or sequencing operator Expressions in a comma separated list are evaluated from left to right with the result of the entire expression being the last expression evaluated As
83. original program and will display that source code not the generated C code 9 1 1 List of filename extensions and languages If a source file name ends in one of the following extensions then GDB infers that its language is the one indicated ic C source file Cy C source file lec cp cpp 9 1 Switching between source languages 101 CXX C f F Fortran source file GDB does not distinguish between Fortran 77 and Fortran f90 90 files s S Assembler source file This actually behaves almost like C but GDB does not skip over function prologues when stepping In addition you may set the language associated with a filename extension See Displaying the language page 103 9 1 2 Setting the working language If you allow GDB to set the language automatically expressions are interpreted the same way in your debugging session and your program If you wish you may set the language manually To do this issue the command set language lang where langis the name of a language such as c For a list of the supported languages type set language Setting the language manually prevents GDB from updating the working language automatically This can lead to confusion if you try to debug a program when the working language is not the same as the source language when an expression is acceptable to both languages but means different things For instance if the current sourc
84. reason breakpoint hit bkptno 1 thread id 1 frame addr 0x00002a08 func main args file hello c line 23 gdb The exec show arguments command Synopsis exec show arguments Prints the arguments of the program GDB command The corresponding GDB command is show args Example N A The exec step Command Synopsis exec step Asynchronous command Resumes execution of the inferior program stopping when the beginning of the next source line is reached if the next source line is not a function call If it is stop at the first instruction of the called function GDB command The corresponding GDB command is step Example Stepping into a function exec step running gdb anon Ngu stopped reason end stepping range thread id 1 frame addr 0x000029d0 func call args name a name b file hello c line 15 gdb 21 7 GDB MI program control 335 Regular stepping exec step running gdb Nou Ngu stopped reason end stepping range thread id 1 frame addr 0x000029d8 func call args name a name b file hello c line 16 gdb The exec step instruction command Synopsis exec step instruction Asynchronous command Resumes the inferior which executes one machine instruction The output once GDB has stopped will vary depending on whether we have stopped in the middle of a source line or not In the former case the address at which t
85. refer to symbols that contain unusual characters which GDB ordinarily treats as word delimiters The most frequent case is in referring to static variables in other source files see Program variables page 84 File names are recorded in object files as debugging symbols but GDB would ordinarily parse a typical file name like foo c as the three words foo c To allow GDB to recognize foo c as a single symbol enclose it in single quotes for example p foo c x looks up the value of x in the scope of the file oo c info address symbol Describe where the data for symbol is stored For a register variable this says which register it is kept in For anon register local variable this prints the stack frame offset at which the variable is always stored Note the contrast with print amp symbol which does not work at all for a register variable and for a stack local variable prints the exact address of the current instantiation of the variable whatis expr Print the data type of expression expr expr is not actually evaluated and any side effecting operations such as assignments or function calls inside it do not take place See Expressions page 83 whatis Print the data type of the last value in the value history ptype typename Print a description of data type typename typename may be the name of a type or for C code it may have the form class class name struct struct tag u
86. regular watchpoint that is it will trigger when the memory location is accessed for writing See Enhanced support for watchpoints and breakpoints page 208 Note that break 1list will report a single list of watchpoints and breakpoints inserted GDB command The corresponding GDB commands are wat ch awatch and rwatch Example Setting a watchpoint on a variable in the main function gdb break watch i done wpt number 2 exp i 318 The GDB MI Interface gdb exec continue running gdb stopped reason watchpoint trigger wpt number 2 exp i value old 0 new 7 thread id 1 frame addr 0x000029c4 func main args file hello c line 8 gdb Setting a watchpoint on a variable local to a function GDB will stop the program execution twice first for the variable changing value then for the watchpoint going out of scope gdb break watch j done wpt number 2 exp 4 gdb exec continue running gdb stopped reason watchpoint trigger wpt number 2 exp j value old 0 new 17 thread id 1 frame addr 0x000029be func call args file hello c line 10 gdb exec continue running gdb stopped reason watchpoint scope wpnum 2 thread id 1 frame addr 0x000029ec func main args file hello c line 18 gdb Listing breakpoints and watchpoints at different points in the program execution Note that once the wat
87. set Once these breakpoints are set they are treated just like the breakpoints set with the break command You can delete them disable them or make them conditional the same way as any other breakpoint The syntax of the regular expression is the standard one used with tools like grep Note that this is different from the syntax used by shells so for instance foo matches all functions that include an fo followed by zero or more os There is an implicit leading and trailing the regular expression you supply so to match only functions that begin with foo use foo When debugging C programs rbreak is useful for setting breakpoints on overloaded functions that are not members of any special classes Print a table of all breakpoints watchpoints and catchpoints set and not deleted with the following columns for each breakpoint Breakpoint Numbers Breakpoint Type watchpoint or catchpoint Disposition Whether the breakpoint is marked to be disabled or deleted when hit Enabled or Disabled Enabled breakpoints are marked with y n marks breakpoints that are not enabled Address Where the breakpoint is in your program as a memory address What Where the breakpoint is in the source for your program as a file and line number If a breakpoint is conditional info break shows the condition on the line following the affected breakpoint breakpoint commands if any are listed after that inf
88. shows no output from info threads and always rejects the thread command like this gdb info threads gdb thread 1 Thread ID 1 not known Use the info threads command to see the IDs of currently known threads Following commands are used to debug multi threaded programs e thread threadno a command to switch among threads e info threads a command to inquire about existing threads e thread apply threadno all args acommand to apply a command to a list of threads The GDB thread debugging facility allows you to observe all threads while your program runs but whenever GDB takes control one thread in particular is always the focus of debugging This thread is called the current thread Debugging commands show program information from the perspective of the current thread Whenever GDB detects a new thread in your program it displays the target system s identification for the thread with a message in the form New systag systag is a Running Programs Under GDB thread identifier whose form varies depending on the particular system For example on LynxOS you might see New process 35 thread 27 when GDB notices a new thread In contrast on an SGI system the systag is simply something like process 368 with no further qualifier For debugging purposes GDB associates its own thread number always a single integer with each thread in your program info threads Display a summary of all
89. specify several directory names separated by whitespace or by a system dependent separator character on Unix on MS DOS and MS Windows If directory is already in the path it is moved to the front so it is searched sooner You can use the string cwd to refer to whatever is the current working directory at the time GDB searches the path If you use instead it refers to the directory where you executed the path command GDB replaces in the directory argument with the current path before adding directory to the search path 4 5 Working directory Each time you start your program with run it inherits its working directory from the current working directory of GDB The GDB working directory is initially whatever it inherited from its parent process typically the shell but you can specify a new working directory in GDB with the cd command The GDB working directory also serves as a default for the commands that specify files for GDB to operate on See Commands to specify files page 125 Following commands are used to set the working directory for your program cd directory Set the GDB working directory to directory pwd Print the GDB working directory 4 6 Program Input and Output By default the program you run under GDB does input and output to the same terminal that GDB uses GDB switches the terminal to its own terminal modes to interact with you but it records the terminal modes your program was usin
90. stack traces containing mixed language frames Java and C C of both live Java processes and core files This has been implemented by adding subcommands for Java VM debugging to gdb The stack trace functionality requires Java SDK version 1 3 1 02 or later versions for HP UX To nd the availability of Java SDK version 1 3 1 02 or later go to the HP web site for Java http www hp com go java Java stack unwind and the gdb Java subcommands features are available in gdb version 4 5 and later versions From gdb version 5 3 and later versions it requires SDK 1 4 2 10 and later versions or JDK 1 5 0 03 and later versions in order to use the Java VM debugging features In order to use this functionality the GDB_JAVA_UNWINDLIB environment variable must be set to the path name of the Java unwind library This environment variable must be set for normal java debugging and java corefile debugging The default location of the Java unwind library on various systems is shown following The examples are for SDK 1 4 if you are using JDK 1 5 substitute opt javal 5 for opt javal 4 e For 32 bit IPF applications export GDB _JAVA_UNWINDLIB opt javal 4 jre lib IA64N server libjunwind so e For 64 bit IPF applications export GDB _JAVA_UNWINDLIB opt javal 4 jre lib IA64W server libjunwind so e For 32 bit PA applications export GDB _JAVA_UNWINDLIB opt javal 4 jre lib PA_RISC server libjunwind sl e For 64 bit PA applications export GDB JAVA
91. start with the inline debugging on This option is used to set the limited source level debugging without compiling 2 1 3 Redirecting WDB input and output to a file To redirect WDB input and output to a file use either of these commands to start the debugger script logl gdb or gdb tee logl 2 2 Quitting GDB quit expression q To exit GDB use the quit command abbreviated q or type an end of file character usually C d If you do not supply expression GDB will terminate normally otherwise it will terminate using the result of expression as the error code An interrupt often C c does not exit from GDB but rather terminates the action of any GDB command that is in progress and returns to GDB command level It is safe to 30 Getting In and Out of GDB type the interrupt character at any time because GDB does not allow it to take effect until a time when it is safe You can use the detach command to release an attached process or device 2 3 Shell commands If you need to execute occasional shell commands during your debugging session there is no need to leave or suspend GDB you can just use the she11 command shell command string Invoke a standard shell to execute command string If it exists the environment variable SHELL determines which shell to run Otherwise GDB uses the default shell bin sh on UNIX systems COMMAND COM on MS DOS and so on The utility make is often needed in
92. string Z Zelt rep end In both cases the value is the output for the value of the element and whitespace can contain spaces tabs and newlines In the repeated case number of repititons is the number of consecutive array elements which contain that value and repetition stringisa string which is designed to convey to the user that repetition is being depicted Once all the array elements have been output the array annotation is ended with Z Zarray section end 20 4 Frames Whenever GDB prints a frame it annotates it For example this applies to frames printed when GDB stops output from commands such as backtrace or up ete The frame annotation begins with Z Zframe begin level address level string where level is the number of the frame 0 is the innermost frame and other frames have positive numbers address is the address of the code executing in that frame and level string isa string designed to convey the level to the user address is in the form 0x followed by one or more lowercase hex digits note that this does not depend on the language The frame ends with Z Zframe end Between these annotations is the main body of the frame which can consist of 20 4 Frames 299 e Z Zfunction call function call string where function call string is text designed to convey to the user that this frame is associated with a function call made by GDB to a function in the program being debugged e 2Z Zsignal
93. system does not recognize this automatically when you run a different shell you may need to run sh on it explicitly sh configure host If you run configure from a directory that contains source directories for multiple libraries or programs such as the gdb gdb 199991101 source directory for version gdb 199991101 configure creates configuration files for every directory level underneath unless you tell it not to with the norecursion option You can run the configure script from any of the subordinate directories in the GDB distribution if you only want to configure that subdirectory but be sure to specify a path to it For example with version gdb 199991101 type the following to configure only the bfd subdirectory cd gdb gdb 199991101 bfd configure host You can install gdb anywhere it has no hardwired paths However you should make sure that the shell on your path named by the SHELL environment variable is publicly readable Remember that GDB uses the shell to start your program some systems refuse to let GDB debug child processes whose programs are not readable A 1 Compiling GDB in another directory If you want to run GDB versions for several host or target machines you need a different gdb compiled for each combination of host and target configure is designed to make this easy by allowing you to generate each configuration in a separate subdirectory rather than in the source directory If your make program h
94. tetr lee M gdb data list register names 1 2 3 done register names r1 r2 r3 gdb The data list register values command Synopsis data list register values fmt regno Display the registers contents fmt is the format according to which the registers contents are to be returned followed by an optional list of numbers specifying the registers to display A missing list of numbers indicates that the contents of all the registers must be returned Allowed formats for fmt are Hexadecimal Octal Binary Decimal Raw Natural GDB command The corresponding GDB commands are info reg info all reg and in gdbtk gdb fetch registers Z k Q t O K Example For a PPC MBX board note line breaks are for readability only they do not appear in the actual output gdb data list register values r 64 65 done register values number 64 value 0xfe00a300 number 65 value 0x00029002 gdb data list register values x 324 The GDB MI Interface done register values number 0 value 0xfe0043c8 number 1 value 0x3f 88 number 2 value 0xfffffffe number 3 value 0x0 number 4 value 0xa number 5 value 0x3 68 number 6 value 0x3fff58 number 7 value 0xfe011e98 number 8 value 0x2 number 9 value 0x a202820 number 10 value 0xfa202808 number 11 value 0x1 number 12 value 0x0 number
95. then look at the stack trace to understand where and how the problem occurred 14 10 8 2 Stop when freeing a block if bad writes occurred outside block boundary WDB enables you to locate problems caused by heap block over flow or underflow with the command InInteractive debugging mode set heap check bounds on off In batch mode debugging check bounds on off When bounds checking is turned on WDB allocates extra space at the beginning and end of a block during allocation and fills it up with a specific pattern When blocks are freed WDB verifies whether these patterns are intact If they are corrupted an under flow or over flow must have occurred and WDB reports the problem If you want to nd corruption at any time use the info corruption command The info corruption command can detect memory corruption in an application That is it reports all the memory blocks that have over writes and under writes 174 HP UX Configuration Specific Information A 14 10 8 3 Stop when a specified block address is allocated or deallocated Syntax info corruption lt file name gt The run time memory checking must be enabled before using the info corruption command to detect memory corruption The corruption information is written to a file specified in the file name argument if provided Otherwise it is printed to the stdout NOTE Turning on bounds checking increases the program s memory requirements because the extra guard
96. threads currently in your program GDB displays for each thread in this order 1 the thread number assigned by GDB 2 the target system s thread identifier systag 3 the current stack frame summary for that thread An asterisk to the left of the GDB thread number indicates the current thread For example gdb info threads 3 process 35 thread 27 0x34e5 in sigpause 2 process 35 thread 23 0x34e5 in sigpause 1 process 35 thread 13 main argc 1 argv 0x7ffffff8 at threadtest c 68 On HP UX systems For debugging purposes GDB associates its own thread number a small integer assigned in thread creation order with each thread in your program Whenever GDB detects a new thread in your program it displays both GDB s thread number and the target system s identification for the thread with a message in the form New systag systag is a thread identifier whose form varies depending on the particular system For example on HP UX you see New thread 2 system thread 26594 when GDB notices a new thread On HP UX systems you can control the display of thread creation messages Following commands are used to control the display of thread creation set threadverbose on Enable the output of informational messages regarding thread creation The default setting is on You can set it to of f to stop displaying of messages set threadverbose off Disable the output of informational messages regarding thread creatio
97. times we can use s the next two times we use n to avoid falling into the xst rdup subroutine gdb s Ox3b5c 532 if rquote def _rquote gdb s 0x3b80 535 lquote lq nil lq 0 def lquote xstrdup lq gdb n 536 rquote rq nil rq 0 def_rquote xstrdup rq gdb n 538 len lquote strlen rquote 1 8 Printing Variable Values The last line displayed looks a little odd in the listing above we can examine the variables 1quote and rquote to see if they are in fact the new left and right quotes we specified We use the command p print to view their values 1 6 Stepping into a subroutine 21 gdb p lquote 1 0x35d40 lt QUOTE gt gdb p rquote 2 0x35d50 lt UNQUOTE gt 1 9 Listing Source Code lquote and rquote are indeed the new left and right quotes To look at some context we can display ten lines of source surrounding the current line with the 1 list command gdb 1 533 xfree rquote 534 535 lquote lq nil lq 0 def_lquote xstrdup lq 536 rquote rq nil rq 0 def_rquote xstrdup rq 537 538 len_lquote strlen rquote 539 len _rquote strlen lquote 540 541 542 void Let us step past the two lines that set len_1lquote and len_rquote and then examine the values of those variables gdb n 539 len _rquote strlen lquote gdb n 540 gdb p len_lqu
98. times the brk value changes The following commands are supported info heap high mem Displays the number of times brk value changes for a given run 180 HP UX Configuration Specific Information set heap check high mem count Stops when brk value has moved X_number X number of times Limitations e This feature assumes that an application has a deterministic memory allocation pattern from one run to another e The high_mem feature is not supported in batch mode debugging 14 11 Thread Debugging Support A 14 11 1 HP WDB provides thread debugging support for kernel user and MxN threads You can exclusively disable or enable specific thread execution Advanced thread debugging support in HP WDB enables you to view information on pthread primitives and detect certain thread related conditions NOTE WDB supports pthread parallelism but it does not support compiler generated parallelism such as parallelism with directives Support for Enabling and Disabling Specific Threads When you suspect that a specific thread is causing a problem while debugging a multi threaded application you can suspend the execution of other threads in the application and debug the doubtful thread exclusively HP WDB 3 2 and later versions provide the following commands to disable and enable specific thread execution thread disable This command prevents the specified threads from running until they are enabled again using the thread en
99. to a large number to prevent complaints from being suppressed show complaints Displays how many symbol complaints GDB is permitted to produce By default GDB is cautious and asks the user to confirm on certain commands For example if you try to run a program which is already running gdb run The program being debugged has been started already Start it from the beginning y or n If you are willing to unflinchingly face the consequences of your own commands you can disable this feature set confirm off Disables confirmation requests 284 Controlling GDB set confirm on Enables confirmation requests the default show confirm Displays state of confirmation requests 17 7 Optional messages about internal happenings set debug arch show debug arch set debug event show debug event set debug expression show debug expression set debug overload show debug overload set debug remote show debug remote set debug serial show debug serial set debug target show debug target set debug varobj Turns on or off display of gdbarch debugging info The default is off Displays the current state of displaying gdbarch debugging information Turns on or o display of GDB event debugging information The default is o Displays the current state of displaying GDB event debugging info Turns on or off display of GDB expression debugging information The default is o Displays the current state of display
100. to separate the expression from the text that follows for the user and value is the actual value being displayed 20 6 Annotation for GDB input When GDB prompts for input it annotates this fact so it is possible to know when to send output when the output from a given command is over etc Different kinds of input each have a different input type Each input type has three annotations a preannotation which denotes the beginning of any prompt which is being output a plain annotation which denotes the end of the prompt and then a post annotation which denotes the end of any echo which may or may not be associated with the input For example the prompt input type features the following annotations 20 5 Displays 301 Z Zpre prompt Z Zprompt Z Zpost prompt The input types are prompt When GDB is prompting for a command the main GDB prompt commands When GDB prompts for a set of commands like in the commands command The annotations are repeated for each command which is input overload choice When GDB wants the user to select between various overloaded functions query When GDB wants the user to confirm a potentially dangerous operation prompt for continue When GDB is asking the user to press return to continue Note Don t expect this to work well instead use set height 0 to disable prompting This is because the counting of lines is buggy in the presence of annotations 20 7 Errors Z Zquit This
101. two this specifies the line of fset lines down from the first linespec Specifies the line of fset lines before the last line printed Specifies line number in the source file filename Specifies the line that begins the body of the function function For example in C this is the line with the open brace Specifies the line of the open brace that begins the body of the function function in the file filename You only need the file name with a function name to avoid ambiguity when there are identically named functions in different source files Specifies the line containing the program address address address may be any expression There are two commands for searching through the current source file for a regular expression forward search regexp Thecommand forward search regexp checks search regexp Examining Source Files each line starting with one of the following in the last line listed for a match of the regexp It lists the line that is found You can use the synonym search regexp or abbreviate the command name as fo reverse search regexp The command reverse search regexp checks each line starting with the one before the last line listed and going backward for a match for the regexp It lists the line s that is found You can abbreviate this command as rev 7 3 Specifying source directories Executable programs sometimes do not record the directories of the source files from which they were compile
102. type column identifies what kind of breakpoint is shown breakpoint watchpoint long jmp longjmp resume until finish shlib events 5 1 2 Setting catchpoints 56 Normal explicitly set breakpoint Normal explicitly set watchpoint Internal breakpoint used to handle correctly stepping through longjmp calls Internal breakpoint at the target of a longjmp Temporary internal breakpoint used by the GDB until command Temporary internal breakpoint used by the GDB finish command Shared library events You can use catchpoints to cause the debugger to stop for certain kinds of program events such as C exceptions or the loading of a shared library Use the catch command to set a catchpoint catch event Stop when event occurs event can be any of the following throw The throwing of a C exception catch The catching of a C exception exec A call to exec This is currently only available for HP UX fork A call to fork This is currently only available for HP UX Stopping and Continuing vfork A call to v ork This is currently only available for HP UX load load The dynamic loading of any shared library libname or the loading of the library 1ibname This is currently only available for HP UX unload unload The unloading of any dynamically loaded libname shared library or the unloading of the library 1ibname This is currently only available for HP UX tcatch event Seta catchpoint that
103. type in memory a section of an array or an array of dynamically determined size for which only a pointer exists in the program You can do this by referring to a contiguous span of memory as an artificial array using the binary operator The left operand of should be the first element of the desired array and be an individual object The right operand should be the desired length of the array The result is an array value whose elements are all of the type of the left argument The first element is actually the left argument the second element comes from bytes of memory immediately following those that hold the first element and so on Here is an example If a program says int array int malloc len sizeof int you can print the contents of array with 8 3 Artificial arrays 85 p array len The left operand of must reside in memory Array values made with in this way behave just like other arrays in terms of subscripting and are coerced to pointers when used in expressions Artificial arrays most often appear in expressions via the value history see Value history page 95 after printing one out Another way to create an artificial array is to use a cast This re interprets a value as if it were an array The value need not be in memory gdb p x short 2 0x12345678 1 0x1234 0x5678 As a convenience if you leave the array length out as in type value GDB calculates the si
104. where the component next points to the next one you can print the contents of the next one with this p S next You can print successive links in the chain by repeating this command using the RET key Note that the history records values not expressions If the value of x is 4 and you type these commands print x set x 5 then the value recorded in the value history by the print command remains 4 even though the value of x has changed show values Print the last ten values in the value history with their item numbers This is like p 9 repeated ten times except that show values does not change the history show values n Print ten history values centered on history item number n show values Print ten history values following the values last printed If no more values are available show values produces no display Pressing RET to repeat show values nhas exactly the same effect as show values F 8 9 Convenience variables GDB provides convenience variables that you can use within GDB to hold on to a value and refer to it later These variables exist entirely within GDB They are not part of your program and setting a convenience variable has no direct effect on further execution of your program That is why you can use them freely 96 Examining Data Convenience variables are prefixed with Any name preceded by can be used for a convenience variable unless it is one of the predefined machine specific register
105. your program stopped in another thread after continuing or even single stepping This happens whenever some other thread runs into a breakpoint a signal or an exception before the first thread completes whatever you requested On some OSes you can lock the OS scheduler and thus allow only a single thread to run set scheduler locking mode Set the scheduler locking mode If it is of then there is no locking and any thread may run at any time If on then only the current thread may run when the inferior is resumed The step mode optimizes for single stepping It stops other threads from seizing the prompt by preempting the current thread while you are stepping Other threads will only rarely or never get a chance to run when you step They are more likely to run when you next over a function call and they are completely free to run when you use commands like continue until or finish However unless another thread hits a breakpoint during its timeslice they will never steal the GDB prompt away from the thread that you are debugging show scheduler locking Display the current scheduler locking mode Stopping and Continuing 6 Examining the Stack When your program has stopped the first thing you need to know is where it stopped and how it got there Each time your program performs a function call information about the call is generated The information includes the location of the call in your progra
106. 01 Free Software Foundation Inc Hewlett Packard Wildebeest 3 0 based on GDB is covered by the GNU General Public License Type show copying to see the conditions to change it and or distribute copies Type show warranty for warranty support GDB reads only enough symbol data to know where to find the rest when needed as a result the first prompt comes up very quickly 1 2 Setting Display width We now tell GDB to use a narrower display width than usual so that examples fit in this manual gdb set width 70 We need to see how the m4 built in changequote works Having looked at the source we know the relevant subroutine is m4_changequote so we set a breakpoint there with the GDB break command 1 3 Setting Breakpoints Here we describe how to set a breakpoint gdb break m4 changequote Breakpoint 1 at 0x62f4 file builtin c line 879 1 4 Running the executable under GDB Using the run command we start m4 under GDB control As long as the control does not reach the m4_ changequote subroutine the program runs as usual gdb run Starting program work Editorial gdb gnu m4 m4 define foo 0000 foo 0000 To trigger the breakpoint we call changequote GDB suspends execution of m4 displaying information about the context where it stops changequote lt QUOTE gt lt UNQUOTE gt Breakpoint 1 m4_changequote argc 3 argv 0x33c70 at builtin c 879 879 if bad_argc TOKEN DATA TEXT argv 0 argc 1 3
107. 1 8 Cannot insert breakpoints number number number number number number 867 860 875 853 846 735 file String ce file String cc file String cc Under some operating systems breakpoints cannot be used in a program if any other process is running that program In this situation attempting to run or continue a program with a breakpoint causes GDB to print an error message Cannot insert breakpoints The same program may be running in another process When this happens you have three ways to proceed 1 Remove or disable the breakpoints then continue 2 Suspend GDB and copy the file containing your program to anew name Resume GDB and use the exec file command to specify that GDB should run your program under that name Then start your program again 3 Relink your program so that the text segment is nonsharable using the linker option N The operating system limitation may not apply to nonsharable executables A similar message can be printed if you request too many active hardware assisted breakpoints and watchpoints Stopped cannot insert breakpoints You may have requested too many hardware breakpoints and watchpoints This message is printed when you attempt to resume the program since only then GDB knows exactly how many hardware breakpoints and watchpoints it needs to insert 5 1 Breakpoints 63 When this message is printed you need to disable or remove some of the hardware
108. 8 Stopping and Continuing e Enabled once The breakpoint stops your program but then becomes disabled e Enabled for deletion The breakpoint stops your program but immediately after it does so it is deleted permanently A breakpoint set with the tbreak command starts out in this state You can use the following commands to enable or disable breakpoints watchpoints and catchpoints disable breakpoints Disable the specified breakpoints or all range breakpoints if none are listed A disabled breakpoint has no effect but is not forgotten All options such as ignore counts conditions and commands are remembered in case the breakpoint is enabled again later You may abbreviate disable as dis enable breakpoints Enable the specified breakpoints or all defined range breakpoints They become effective once again in stopping your program enable breakpoints once Enable the specified breakpoints temporarily range GDB disables any of these breakpoints immediately after stopping your program enable breakpoints delete Enable the specified breakpoints to work once range then die GDB deletes any of these breakpoints as soon as your program stops there Except for a breakpoint set with tbreak see Setting breakpoints page 52 breakpoints that you set are initially enabled subsequently they become disabled or enabled only when you use one of the commands above The command until can set and delete a
109. 9 Break ConditonNnS tieien itiren ase r eE aE N E E RE at 59 5 1 6 Breakpoint command lists s nsnsseseneesseseesesseseesessesesseseesensestesesseerenseseesessesresese 61 51 7 Bre kp int Men Sosson see erais E EE AEE E EESE E 62 5 1 8 Cannot insert breakpoints ssesssssssssessserssrsessserssrsrseserssissrereesseesresrenseeseeseenss 63 5 2 Continuing and steppi gnere sisri sae eerie R E rA ATER E NEEE SEE 64 5 3 UPN SG oian nr n es aE EE E E E E E EEE E E eas 67 5 4 Stopping and starting multi thread programs cs ccccscecsesseseesecsserseeseesenceenensees 69 6 Examining the Stack aarin EEE e E E luca EE E A EEE AE ia 71 6 1 Stack frani S ioten ean TR Era e aSa cu EEA E aN 71 6 2 Stacks Without fraies mrri iniiai tE E EAEE EA E E OS Eai 72 6 3 Commands for Examining the Stack ii assis tepenaktinecssassupieedan ene tay sagedvvatnecdbernspnaeder nents 72 6 4 Ba Cha Ces gonnen r r e snes catay ested E OE A A e ET E E SE ada e aas 72 6 9 Selecting A framen ocen tinned an E r ee nS E 73 6 6 Information about a fames esei eene reatie Ea E casey aaaea eA STENE SEERDE TENE a arenes 74 7 Examining SOOKE Filesro 5 otic ceyercewbiveode Spon cated cia E E cudiss 77 7 Printing so rte NeSeseme nae iaa eapi a a e ar e R etuaiaes 77 7 oearchine source fles arreta aa A a Va a 78 7 3 Specifying Source directories itai doent teh aea iaee aaia e aaa a a 79 7 4 Sourcs nd machine codeine rers kiesen a a e EE E E OE EEE a ei
110. B will produce error messages Otherwise no output is produced except a completion notification GDB command The corresponding GDB command is file Example gdb file exec and symbols kwikemart marge ezannoni TRUNK mbx hello mbx done gdb The file exec file command Synopsis file exec file file Specify the executable file to be debugged Unlike file exec and symbol1s the symbol table is not read from this file If used without argument GDB clears the information about the executable file No output is produced except a completion notification 21 7 GDB MI program control 337 GDB command The corresponding GDB command is exec file Example gdb file exec file kwikemart marge ezannoni TRUNK mbx hello mbx done gdb The file list exec sections command Synopsis file list exec sections List the sections of the current executable file GDB command The GDB command info file shows among the rest the same information as this command gdbtk has a corresponding command gdb_load_info Example N A The file list exec source files command Synopsis file list exec source files List the source files for the current executable GDB command There is no GDB command which directly corresponds to this one gdbtk has an analogous command gdb_listfiles Example N A The file list shared libraries command Synopsis file list shared libraries List the s
111. B commands and HP WDB equivalents 275 Table 16 28 T continued XDB Command Equivalent WDB Command ta No equivalent tb No equivalent tc No equivalent td td with xdb tui tf tf with xdb tui toggle fregs with tui tm No equivalent top frame 0 tr No equivalent s ts with xdb tui 16 8 9 U through Z Table 16 29 U through Z XDB Command Equivalent WDB Command u u with xdb tui update with tui U U with xdb tui refresh with tui undef name def name follow with empty command list undef No equivalent up down up number down number v v with xdb list v location v location with xdb list location V depth V depth with xdb frame depth va address va address with xdb disas address va label va label with xdb disas label va label offset va label offset with xdb disas label offset w number w number with xdb tui winheight src number with tui x expr No equivalent xdb program gdb xdb program gdb xdb tui program 276 XDB to WDB Transition Guide Table 16 29 U through Z continued XDB Command xdb program corefile Equivalent WDB Command gdb xdb program c corefile xdb d dir gdb xdb d dir xdb P pid program gdb xdb program pid xdb i after starting run lt file xdb o after starting run gt file z number s z number s with x
112. B to stop whenever a block at the given address gets allocated or deallocated set heap check watch address Not supported in batch mode Instructs malloc to return null after lt num gt invocations of malloc set heap check null check lt num gt Not supported in batch mode Instructs malloc to return null after lt num gt bytes have been allocated by malloc set heap check null check size lt size gt Not supported in batch mode Specifies the seed value to be used for generating random null check count set heap check seed value lt num gt Not supported in batch mode 14 10 Debugging Memory Problems 177 Table 14 1 Memory Debugging Commands in Interactive and Batch Mode continued Command Description Interactive mode Batch mode Specifies the random range to be set heap check Not supported in batch mode used by random range random range lt num gt Specifies the time interval tobe used set heap check Not supported in batch mode for incremental memory profile interval lt num gt Perform incremental profile for set heap check Not supported in batch mode lt num gt interval periods where each repeat lt num gt period duration is defined by set heap check interval command The default value is 100 NULL pointer return by memory catch nomem Not supported in batch mode allocators used with set heap check on with without null check enabled 2
113. CollectableDate type class RWCollectableDate lt no data fields gt 9 4 1 4 C and C defaults If you allow GDB to set type and range checking automatically they both default to off whenever the working language changes to C or C This happens regardless of whether you or GDB selects the working language If you allow GDB to set the language automatically it recognizes source files whose names end with c C or cc and so on and when GDB enters code compiled from one of these files it sets the working language to C or C Refer to See Having GDB infer the source language page 102 for further details 9 4 1 5 C and C type and range checks By default when GDB parses C or C expressions type checking is not used However if you turn type checking on GDB considers two variable types equivalent if e The two variables are structured and have the same structure union or enumerated tag e The two variables have the same type name or types that have been declared equivalent through typedef 110 Using GDB with Different Languages Range checking if turned on is done on mathematical operations Array indices are not checked since they are often used to index a pointer that is not itself an array 9 4 1 6 GDB and C The set print unionand show print union commands apply to the union type When set to on any union that is inside a struct or class is also printed Otherwise it appears as
114. DB commands and HP WDB equivalents 271 Table 16 22 B continued 16 8 3 C through D Table 16 23 C through D XDB Command Equivalent WDB Command bu depth bu depth with xdb The finish command is equivalent to the sequence bu c db to continue out of the current routine bx depth bx depth with xdb XDB Command Equivalent WDB Command c c continue c location until location c continue C location until location D dir D dir with xdb dir pathname da number No equivalent da No equivalent db clear db number delete number db delete dbc undisplay def name replacement text def name GDB prompts for commands down up down number dp up number No equivalent dpm index No equivalent 272 XDB to WDB Transition Guide dpm No equivalent Dpt No equivalent Dpx No equivalent 16 8 4 F through K Table 16 24 F through K XDB Command Equivalent WDB Command f printf style fmt No equivalent fr fr with xdb tui display fregs with tui g line g line with xdb go line tb line followed by jump line g label No equivalent g lines g lines with xdb go lines tb lines followed by jump lines g g with xdb go 1 tb 1 followed by jump 1 gr gr with xdb tui display regs with tui h h
115. Debugging with GDB Manual The GNU Source Level Debugger HP Part Number 5992 4701 i Published February 2009 if Edition 19 Copyright 2009 Hewlett Packard Development Company L P Confidential computer software Valid license from HP required for possession use or copying Consistent with FAR 12 211 and 12 212 Commercial Computer Software Computer Software Documentation and Technical Data for Commercial Items are licensed to the U S Government under vendor s standard commercial license The information contained herein is subject to change without notice The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services Nothing herein should be construed as constituting an additional warranty HP shall not be liable for technical or editorial errors or omissions contained herein UNIX is a registered trademark of The Open Group Java is a registered trademark of Sun Microsystems Inc Table of Contents Summary Ob SDB cass 5 stares I TE A E i ole Re ve E ieee uma aoa na tases 15 BGCO SOLEW ALC AENA EES E NERE PEANT A os venue a AA EN EE EE AAA 15 Contributors to GDB iscsi esses tecesbicitedishiedeeeeocanecsapu ea eean dated E EI OS NTN SN 15 TA Sample GDB Session enin olen incest A E E ola psecdiss cite son cacens E T AE 19 Tel Loading th Exec tablem nresnani t eeta aa EEEE AREE Eais 19 1 2 Setting Display Widthsninisrinrersrririi eriein aeien e ENE
116. Decimal floating point constant Printing Decimal floating point variable e Handling Decimal Floating Point data types e Evaluating Decimal Floating Point data types Printing Type of Decimal floating point data type 14 23 1 Printing Decimal Floating point data types HP WDB versions 5 9 and above enable you to print a decimal floating point data type constant or variable It handles and prints decimal floating point constant or variable when you use common GDB commands such as stack trace and command line calls 14 23 Debugging support for Decimal Floating Point datatype 213 14 23 1 1 Printing Decimal floating point constant gdb print lt num gt lt df dd d1 DF DD DL gt df DF _Decimal32 dd DD _Decimal 4 dl DL _Decimal128 This prints the decimal floating point constant based on the data type 14 23 1 2 Printing Decimal floating point variable gdb print lt fmt gt lt var name gt lt fmt gt df dd dl lt var name gt variable name This prints the decimal floating point variable If you specify format lt fmt gt then it prints the variable based on its data type 14 23 2 Printing Nal Registers On Integrity systems following is the command to print the NaT bit corresponding to a register print Snatr lt reg nbr gt where reg_nbr represents the NaT bit corresponding to a register Example 14 2 Sample Commands to Print NaT Registers Following are sample commands to print NaT registers gdb
117. E ENE E EE 20 T3 Setting Breakpoints iris iee erise Ee aaea bie wea ene ne heehee 20 1 4 Running the executable under GDBesscscr aces sciesisdedspansoshpscctacenp rand demsesaecvs unten ante ceeyects 20 1 5 Stepping to the next line in the source prog ramcss 2 2 wires sical seiatisiuis udanseessneens 20 T6 Stepping into a SUE OU ELI sisii an ea evo coed ed ea EE EAEE a 21 T 7 Examining UNE Sta Ch sieges ds egnir in wearers cups eE Eaa ESE vaginas e Eiaa detente 21 1 8 Primting Variable NV aUCS eA asec ctcbecnevviss est eutsetuaeiaveceeeareitivrse E EES A RE aa 21 T9 TISHING Source Coden ssie en ea boon a a a a a soot 22 1 10 Setting Variable Values During a Session sessssssssessessesetstsstsresessesresseseesesseseseee 22 2 G ting Inand Qut of GDB eoe i A creda a E N A S A 25 2 1 invoking GDB essere aiseanna ieee ea nude EE cab a r A aAa EEE eia 25 Bell Choosing TUS Ot sict aiid unreal iiie E ee atta A A eE E ites aast 26 21 2 Choosing modes nrerin eeraa aeeoea tie EE AE T AA E EA eE E VEAST exe asada Guts 27 2 1 3 Redirecting WDB input and output to a LNG ii cssehsvelecntiettevsievestecmrtunsebaveseredvelhs 30 2 2 Quitting DDB ites pia ow eA vat eE E EON EERE aE EETA EEEE EAE Eaa aE 30 2 3 SHON COMMAS sis aA A EE TANAAN A ETEN 31 TREB AE E E EA EE A E AAE EA AAE AA 33 3L Command Synta sisese arana re A EER EE A EE A E EERE E Eai 33 3 2 Command COM DICH OR se ise e ea EEE aer EE TOE EEEE EEEE ETET 33 33 Getting NON cscctectecdestonsaa
118. ER ga KEET ES ty 230 14 30 1 Debugging the application using GDB under ARIES ceseeeeeeeeeees 231 14 30 1 1 Limitations of GDB Support under ARIES e cece eee ceeeeeeeeeeeees 231 14 30 2 Attaching GDB to an already running emulated procesS ccceceeseeeeees 232 14 30 3 Detecting memory leaks using GDB under ARIES ccceecceesseeeseesseeeseeees 232 14 31 Visual Interface for WDB anr ettare AE VAE EEA E a EA AEAEE EE 233 14 31 1 Starting and stopping Visual Interface for WDB ssssesssessessesrsersrrseesserssesees 233 14 31 2 Navigating the Visual Interface for WDB display cccesceesseesseesseeeeeeees 234 14 31 3 Specifying foreground and background COLOTPS cece cee eeeseeeeeeesseeeeeees 235 14 31 4 Using the X window graphical interface ccccceeeeeseceseeeesceeeeeeseesseeneseees 235 14 315 Using the TUL MOJE initie erna aa eni ra EEEE EE RE A 236 14 31 6 Changing the size of the source or debugger Pane cccceesessecseeseeeeeeees 236 14 31 7 Using commands to browse through source fileS ccceeseseeseeeeeseeeeeeeees 237 14 31 98 Loading so rc fileSniann nisnin eewmne reve cnet ieee a ea veiii i 237 14 31 9 Editing source TIES nran iun ninanasa e a a e A E tases 237 14 31 10 Editing the command line and command line history ccccecceeseeeeees 237 14 31 11 Saving the contents of a debugging session to a fil cc cece este eeeeeees 237 14 32 S
119. ES 5 ccs ncucsuaenrvcesiubeds esbrenar EE PRESEASON EEEE KAIERA E RE eera tirei 214 14 23 3 Handling Decimal Floating Point Data types s sesssesssessessessseisrrseessersssees 214 14 23 4 Evaluating Decimal Floating Point data types sssssssesssssesssersesseesserssesees 214 14 23 4 1 Printing type of Decimal Floating Point variable 0 eceeeeees 215 14 24 Additional Support for binary floating point data type cece cece eseeeeeeeees 216 14 24 1 Support for Binary Floating Point constants f Loo eee ee eee eeeeeseeeeees 216 14 24 2 Support Binary Floating Point variables with format specifier 04 216 T425 Language SUP PONE urinen ee nett ea O El Ace E Hs E EEE 217 14 25 1 Enhanced Java Debugging Support cccissicsiscssswnssenscevascsvrienbernnepsvesevntesnts ovidedys 217 14 25 1 1 Java Stack Unwind Features cccecsecescccececeeeesennaececeeecesesseaeceeeeeenenss 217 14 25 1 2 gdb Subcommands for Java VM Debugging ccceccescseeseeseesseeteenes 218 14 25 1 3 Java coretile debugging SUPPOL ys 1c2riyvscceacsasvepesseeesctanbvsciosi nen eeidaveeeeonares 220 14 25 14 Java attach mode debugging support vc c cc discs ssivcertessinelsaeleinvatinen 220 14 25 2 Enhanced support for C tem plates occcccvercicdisveicelesveioia cisatirneies beeen 221 Table of Contents 14 25 23 Support for _ _fpreg datatype on APP scnanivaces sien savin tention ivaaetines 222 14 25 4 Support for Complex varia
120. Enea Data Systems real time OS os68gdbinit e _ES 1800 Ericsson Telecom AB M68000 emulator esgdbinit You can also request the execution of a command file with the source command source filename Execute the command file filename The lines in a command file are executed sequentially They are not printed as they are executed An error in any command terminates execution of the command file Commands that would ask for confirmation if used interactively proceed without asking when used in a command file Many GDB commands that normally print messages to say what they are doing omit the messages when called from command files 18 4 Commands for controlled output During the execution of a command file or a user defined command normal GDB output is suppressed the only output that appears is what is explicitly printed by the commands in the definition This section describes three commands useful for generating exactly the output you want echo text Print text Nonprinting characters can be included in text using C escape sequences such as n to print a newline No newline is printed unless you specify one In addition to the standard C escape sequences a backslash followed by a space stands for a space This is useful for displaying a string with spaces at the beginning or the end since leading and trailing spaces are otherwise trimmed from all arguments To print and foo use the command echo and foo A backslash at the
121. Eonia EEES Ea EEEE SEEE R KoE aay eaten nies 259 Job control commands ossessi nsennesrn na eie i ads EAEE E EA EE ia Ee 259 Overall breakpoint commandsS ss sesessseissesessseessessreseesserssssresserssesnesseissesneeseessees 260 Auxillary breakpoint commandSs ssssesssssssesessseessissssseesseesssressersrisresserssesneeserssees 261 Breakpoint creation commandSs sessesssesssrseseseessisseeseessersesresseesrisresseissesneeseessens 261 Overall breakpoint commandS s sessessseesseseseseessesssseessersresressersresresseissisneeseessees 262 Global breakpoint COMMAS icssis stone cevaecutasteonasd taverns toe tedawteruastvorherincncarteetts 263 Macro facility commands x25 snes tae serora iei teas var Ladera yee diate 265 Signal control coMMAanNd S s sss ernis ainiin ioir iEn N SEn E erreia as 265 Miscellaneous Commands oea a EE AE ATEA EEE AE ATEA A AEEA EET R ky 265 Data format commands aen a A AN A N AO 266 Macro facility commands senerara reaa E EEE Ie E a ERSE EA 268 Special language Operators ienris nesies ii ie ei ai 269 Special variables eeutasiencasete wnadtnades tans tetennety eeiidss nests bes AEEA ea NERE EERE n iS 269 Variable dent fers succes n aE ira ET E A ETE a 270 V REEE A A AE O EN EE A EAEAN EA ENT AE E EE IEA 270 D EERIE N E E S E E ETE E E NE T A A 271 Cthrough Dosinia eannan EEA R aAA TA ERATA E EA ARER EAE a 272 Fothrough Koror enea ia E EE EAE EE ET EEE EE ory 273 l PEE AEAT EE AEE E E EET E
122. File viewing commands page 255 GDB does not provide a source directory mapping capability and therefore does not have any equivalent of the apm dpm and 1pm commands 16 1 5 Data Viewing and modification commands There are many info commands in addition to those shown here Use help info to get a list The following table lists the XDB and equivalent WDB commands for viewing and modifying the program data 256 XDB to WDB Transition Guide Table 16 4 Data viewing and modification commands XDB Command WDB Equivalent Meaning 1 with xdb info args Move view location forward or followed by info locals backward in source file number lines le string le string with xdb Search source forward for last info common string string lg string lg string with xdb Search source backward for last info variables string string 11 string info functions string Adda directory search path for info variables string source files maint print msymbols file Im show user Show current viewing location or current point of execution lm string show user string List source directory search path list all directories lo class string info func List all source files class string lp info functions Show current scope list program blocks list names symbols lp class string info func List all or matching procedures class string info addr
123. GDB in GNU Linux distributions as well The version number is the same as the one announced when you start GDB show copying Display information about permission for copying GDB show warranty Display the GNU NO WARRANTY statement or a warranty if your version of GDB comes with one 3 3 Getting help 37 38 4 Running Programs Under GDB When you run a program under GDB you must first generate debugging information when you compile it using compiler option ce g O You may start GDB with its arguments if any in an environment of your choice If you are doing native debugging you may redirect your program s input and output debug an already running process or kill a child process 4 1 Compiling for debugging A Following points are noteable while compiling programs for debugging e Compile your program with the g 0 option to generate debugging information e The g 0 option is supported by HP ANSI C and HP aC compilers and GNU gcc compiler e Some compilers do not support the g 0 options together e The g 0 options do not work on machines with instruction scheduling NOTE Older versions of the GNU C compiler permitted a variant option gg for debugging information GDB no longer supports this format if your GNU C compiler has this option do not use it 4 2 Starting your program A run Use the run command to start your program under GDB You must first specify r the program name except on V
124. ISC applications that are not linked with end o Command watch _ target Command line option set display full path that displays the full pathname of the source file name while printing the frame information Command line option set dereference on off when off WDB does not dereference char variables by default Support for show macro macro expand to view and expand macro expressions 14 1 Summary of HP Enhancements to GDB 139 e Support for evaluating macros e Support for printing the execution path entries in the current frame or thread e New Command for Searching a Pattern in the Memory Address Space e New Option to Limit the Number of Frames Unwound e Updated Procedure to Process the Initialization File e Enhancement to the info shared Command e Enhancement tothe info target Command e Support for automatic debugging of shared libraries e Attaching a PA RISC debugger to a PA RISC process e Improvement in the performance of memory debugging for the string option A NOTE For new commands see HP WDB Release Notes available at http www hp com go wdb 14 2 HP UX dependencies 14 2 1 Linker Dependencies Several features available in WDB depend on specific versions of the linker or the compiler e Linker patch required for tobjdebug For releases prior to HP UX 11i v2 for IA and HP UX 11i v1 for PA RISC you must install the latest linker patch to generate object modules that enable faster linking and
125. Less than LE lt Less than or equal to GT gt Greater than GE gt Greater than or equal to Concatenation NOT Logical negation AND Logical AND OR Logical OR EQV Logical equivalence NEQV XOR Logical non equivalence Logical constants are represented as TRUE or FALSE GDB includes support for viewing Fortran common blocks info common Lists common blocks visible in the current frame 9 4 Supported languages 113 info common Lists values of variables in the named common lt common_block_ name gt block Fortran entry points are supported You can set a break point specifying an entry point name 9 4 2 3 Fortran special issues Fortran allows main to be a non main procedure therefore to set a breakpoint in the main program use break _MAIN_orbreak lt program_name gt Do not use break main unless it is the name of a non main procedure 114 Using GDB with Different Languages 10 Examining the Symbol Table The commands described in this chapter allow you to inquire about the symbols names of variables functions and types defined in your program This information is inherent in the text of your program and does not change as your program executes GDB finds it in your program s symbol table in the file indicated when you started GDB see Choosing files page 26 or by one of the file management commands see Commands to specify files page 125 Occasionally you may need to
126. On some operating systems a program cannot be executed outside GDB while you have breakpoints set on it inside GDB You can use the kil 1 command in this situation to permit running your program outside the debugger The kill command is also useful if you wish to recompile and relink your program since on many systems it is impossible to modify an executable file while it is running in a process In this case when you next type run GDB notices that the file has changed and reads the symbol table again while trying to preserve your current breakpoint settings 4 9 Debugging programs with multiple threads 46 In some operating systems such as HP UX and Solaris a single program may have more than one thread of execution The precise semantics of threads differ from one operating system to another but in general the threads of a single program are akin to multiple processes except that they share one address space that is they can all examine and modify the same variables On the other hand each thread has its own registers and execution stack and private memory GDB provides these facilities for debugging multi thread programs e automatic notification of new threads e thread specific breakpoints WARNING These facilities are not yet available on every GDB configuration where the operating system supports threads If your GDB does not support threads these commands have no effect For example a system without thread support
127. Packard Wildebeest based on GDB 5 0 hpwdb 20000516 from the Hewlett Packard Web site report problems to your HP Support Representative Support is covered under the support contract for your HP compiler The fundamental principle of reporting bugs usefully is this report all the facts If you are not sure whether to state a fact or leave it out state it Often people omit facts because they think they know what causes the problem and assume that some details do not matter Thus you might assume that the name of the variable you use in an example does not matter Well probably it does not but one cannot be sure Perhaps the bug is a stray memory reference which happens to fetch from the location where that name is stored in memory perhaps if the name were different the contents of that location would fool the debugger into doing the right thing despite the bug Play it safe and give a specific complete example That is the easiest thing for you to do and the most helpful 22 1 Have you found a bug 361 Keep in mind that the purpose of a bug report is to enable us to x the bug It may be that the bug has been reported previously but neither you nor we can know that unless your bug report is complete and self contained Sometimes people give a few sketchy facts and ask Does this ring a bell Those bug reports are useless and we urge everyone to refuse to respond to them except to chide the sender to report bugs properly
128. Posix shell enter the following command at the HP UX prompt export BATCH RTC on 14 10 Debugging Memory Problems 165 4 Complete one of the following steps to preload the 1ibrtc runtime library e Set the target application to preload librtc by using the rtc option for the chatr command In addition to automatically loading the 1ibrtc library the rtc option for the chatr command also maps the shared libraries as private To enable or disable the target application to preload the librtc runtime library enter the following command at the HP UX prompt chatr rtc lt enable disable gt lt executable gt A NOTE The chatr rtc option preloads the librtc runtime library from the 5 following default paths For 32 bit IPF applications opt langtools lib hpux32 librtc so For 64 bit IPF applications opt langtools lib hpux64 librtc so For 32 bit PA applications opt langtools lib librtc sl For 64 bit PA applications opt langtools lib pa20_64 librtc sl To preload the librtc runtime library from a path that is different from the default paths you must use the LD_PRELOAD environment variable e Instead of automatically preloading librtc and mapping the shared libraries you can explicitly preload the required librtc library after mapping the shared libraries private In the case of HP 9000 systems you must explicitly map the share libraries as private by using the dbg enable option for the chat r command
129. RTC will instrument ALL executables A frame_count no_frames or Sets the number of frames to be printed for leak set heap check frame count context lt no_frames gt min heap _size block size Sets the minimum block size to use for heap or set heap check reporting min heap size lt block_size gt min _leak_size block size Sets the minimum block size to use for leak or set heap check detection min leak size lt block size gt output _dir output_data_dir Specifies the name of the output data directory scramble blocks on off or Enables block scrambling set heap check scramble lt on off gt Batch mode leak detection stops the application at the end when libraries are being unloaded and invokes HP WDB to print the leak or heap data NOTE Itis incorrect usage to use spaces before or after the symbol in the batch mode configuration options in the configuration file rtcconfig Additionally it is incorrect usage to use spaces before the batch mode configuration options For example Correct Usage cat rtcconfig check_leaks on check _heap on files batchrtc4 Incorrect Usage cat rtcconfig check leaks on check_heap on files batchrtc4 Steps for Batch Mode Memory Debugging To use batch memory debugging complete the following steps 1 Compile the source files 2 Create an rtcconfig file in the current directory 3 Dene an environment variable BATCH_RTC If you are using the Korn or
130. S 232 Applications cannot leak memory under ARIES unless they do so on HP 9000 servers HP GDB can be used to detect memory leaks of HP 9000 applications under ARIES Refer to HP GDB documentation for more details HP UX Configuration Specific Information 14 31 Visual Interface for WDB WDB includes an HP supported Visual Interface for WDB with both graphical and terminal modes The interface is based on Vim 5 7 and WDB This interface replaces the tui mode on Itanium based systems When you use the interface you are actually using vim which is a vi compatible editor With the interface you can use vi commands to browse in the WDB display Most of Visual Interface for WDB functionality is also available for emacs users Visual Interface for WDB does not require knowledge of vi commands Visual Interface for WDB identifies you as an emacs user by looking at the environment variable EDITOR If this variable has a value that matches emacs or gmacs or xemacs then Visual Interface for WDB starts in emacs mode automatically E NOTE Ifthe program expects unbuffered input or uses curses termcap or terminfo or otherwise transmits escape or control sequences to the terminal you must use one of the following methods to run Visual Interface for WDB e Start the process in one terminal and attach to it with Visual Interface for WDB e Use the tty command at the debugger prompt so the program s input and output are directed to a
131. Species typedef enum Big tree Acorn Seedling Tree forms typedef enum Caterpillar Cocoon Butterfly Bug_forms struct thing Species it union Tree forms tree Bug_forms bug 8 7 Print settings 93 94 form p struct thing foo Tree Acorn with set print union onineffect p foo would print 1 it Tree form tree Acorn bug Cocoon and with set print union off in effect it would print 1 it Tree form These settings are of interest when debugging C programs set print demangle set print demangle on show print demangle set print asm demangle set print asm demangle on show print asm demangle set demangle style style Examining Data Print C names in their source form rather than in the encoded mangled form passed to the assembler and linker for type safe linkage The default is on Show whether C names are printed in mangled or demangled form Print C names in their source form rather than their mangled form even in assembler code printouts such as instruction disassemblies The default is off Show whether C names in assembly listings are printed in mangled or demangled form Choose among several encoding schemes used by different compilers to represent C names On HP UX WDB automatically chooses the appropriate style The choices for style currently supported are auto Allow GDB to choose a decoding style by inspecting y
132. Stack viewing commands No equivalent Evaluate next previous memory location using format The GDB concept of the top and bottom of the stack is the opposite of XDB so the XDB up is GDB down The following table lists the XDB and equivalent WDB commands for viewing the stack contents Table 16 5 Stack viewing commands XDB Command WDB Equivalent View procedure one level nearer outermost frame of stack higher number down number up number View procedure number levels nearer outermost frame of stack t depth t depth with xdb bt Print stack trace to depth depth T depth T depth with xdb Print stack trace and show local bt full depth vars top frame 0 View procedure at innermost frame of stack 258 XDB to WDB Transition Guide Table 16 5 Stack viewing commands continued XDB Command WDB Equivalent Meaning up down View procedure one level nearer innermost frame of stack lower number up number down number View procedure number levels nearer innermost frame of stack V depth V depth with xdb Display text for current active frame depth procedure or at specified depth on stack 16 1 7 Status viewing command Type the show command with no arguments to get a list of current debugger settings Table 16 6 Status viewing commands XDB Command WDB Equivalent Meaning O I info many kinds show many Display st
133. TE In addition to the set of operations described here we expect the GUI implementation of a variable window to require at least the following operations e gdb show output radix e stack list arguments stack list locals stack select frame Introduction to variable objects in GDB MI The basic idea behind variable objects is the creation of a named object to represent a variable an expression a memory location or even a CPU register For each object created a set of operations is available for examining or changing its properties Furthermore complex data types such as C structures are represented in a tree format For instance the struct type variable is the root and the children will represent the struct members If a child is itself of a complex type it will also have children of its own Appropriate language differences are handled for C C and Java When returning the actual values of the objects this facility allows for the individual selection of the display format used in the result creation It can be chosen among 21 13 GDB MI tracepoint commands 355 binary decimal hexadecimal octal and natural Natural refers to a default format automatically chosen based on the variable type like decimal for an int hex for pointers and so on The following is the complete set of GDB MI operations defined to access this functionality Table 21 1 GDB MI Operations Operation Description var create create
134. Table 16 25 page 273 e Table 16 26 page 274 e Table 16 27 page 275 e Table 16 28 page 275 e Table 16 29 page 276 e Table 16 30 page 277 16 8 1 A Table 16 21 A XDB Command Equivalent WDB Command a cmds No equivalent aa number No equivalent aa No equivalent ab number enable number ab enable ab shared library No equivalent 270 XDB to WDB Transition Guide Table 16 21 A continued XDB Command Equivalent WDB Command abe cmds No exact equivalent but display expr is equivalent to abc print expr am am with xdb set height num apm oldpath newpath No equivalent 16 8 2 B apm newpath No equivalent Table 16 22 B XDB Command Equivalent WDB Command b loc b loc b b ba address ba address with xdb b address bb depth No equivalent use b proc be number expr be number expr with xdb ignore number expr within a commands list bi expr proc bi c expr b class proc cond bnum this expr No equivalent bi C expr No equivalent bp No equivalent bp cmds No equivalent bpc c class rb class bpc C class Use rb class for base classes also bpo proc rb proc bpo class proc b class proc bpt No equivalent bpt cmds No equivalent bpx No equivalent bpx cmds No equivalent bt proc b proc commands bnum finish c end 16 8 Alphabetical lists of X
135. To enable us to x the bug you should include all these things The version of GDB GDB announces it if you start with no arguments you can also print it at any time using show version Without this we will not know whether there is any point in looking for the bug in the current version of GDB The type of machine you are using and the operating system name and version number What compiler and its version was used to compile the program you are debugging e g HP92453 01 A 10 32 03 HP C Compiler Use the what command with the pathname of the compile command what opt ansic bin cc for example to obtain this information The command arguments you gave the compiler to compile your example and observe the bug For example did you use O To guarantee you will not omit something important list them all A copy of the Makefile or the output from make is sufficient If we were to try to guess the arguments we would probably guess wrong and then we might not encounter the bug A complete input script and all necessary source files that will reproduce the bug A description of what behavior you observe that you believe is incorrect For example It gets a fatal signal Of course if the bug is that GDB gets a fatal signal then we will certainly notice it But if the bug is incorrect output we might not notice unless it is glaringly wrong You might as well not give us a chance to make a mistake Even if the proble
136. UNWIN export GDB JAVA UNWIN LIB LIB opt javal 4 jre lib PA_RISC2 0 server libjunwind s1l opt javal 4 jre lib PA_RISC2 0W server libjunwind sl DI D If the SDK is installed in a location other than the default substitute the non default location for opt javal 4 in the previous commands 14 25 1 1 Java Stack Unwind Features The Java stack unwind features are useful for troubleshooting problems in the Java VM Following is a list of the Java stack unwind features e View mixed language frames information including Java frames and C C native frames in a gdb backtrace e Distinguish various Java frame types including interpreted compiled and adapter frames e View Java method name signature and class package name for Java method frames 14 25 Language support 217 Additional stack unwind features are available starting with SDK 1 4 2 These features fall into three categories Java stack unwind enhancements Java heap support and Java threads support These additional features are available as part of the Java stack unwind enhancements e View Java compiled frame inlined methods e View Java interpreted or compiled frame specific information e View Java interpreted or compiled frame arguments and local variables e Disassemble Java method bytecodes e Printout the Java unwind table These additional features are available as part of Java heap support e View Java heap parameters e Du
137. WDB can spend a substantial amount of time collecting stack traces You can improve performance by using the command 14 10 Debugging Memory Problems 173 set heap check min leak size num For example if you use set heap check min leak size 100 WDB does not collect stack traces for allocations smaller than 100 bytes HP WDB still reports leaks smaller than this size but does not include a stack trace 14 10 7 3 Specifying minimum block size The min heap size option reports the heap allocations that exceed the specified number lt num gt of bytes based on the cumulative number of bytes that are allocated at each call site which is inclusive of multiple calls to malloc at a particular call site For example set heap check min heap size 100 When the option min heap size is set to 100 GDB reports all the cumulative block allocations that 100 bytes at each call site 14 10 8 Scenarios in memory debugging 14 10 8 1 Stop when freeing unallocated or deallocated blocks WDB enables you to locate improper calls to free and realloc with the command Ininteractive debugging mode set heap check free on off Inbatch mode debugging check free on off With this setting on whenever the program calls free or realloc WDB inspects the parameters to verify that they are pointing to valid currently allocated heap blocks If WDB detects an erroneous call to free it stops the program and reports this condition You can
138. WDB or librtc s1 so respectively 5 Atthe end of the run output data file is created in output_data_dir if defined in rtcconfig or the current directory HP WDB creates output data file for each run It creates a separate file for leak detection and heap information The naming convention for output files is as follows lt file name gt lt pid gt lt suffix gt where lt pid gt is the process id and the value for lt sux gt can be either leaks heap or mem A NOTE During operations such as system 3s and popen which invoke a new shell Librtc s1 so must not be loaded to the invoked shell You must use LD _PRELOAD_ ONCE instead of LD_PRELOAD to exclusively load the librtc s1 so file to the calling process only Following is the syntax for using LD PRELOAD ONCE LD PRELOAD ONCE opt langtools lib librtc sl 14 10 5 2 Environment variable setting for Batch mode debugging Batch mode memory leak detection uses the following environment variables e GDBRTC_CONFIG specifies the location of rtc configuration file If this option is not specified the configuration file is assumed to be in the current location and 14 10 Debugging Memory Problems 167 has the filename rt cconfig If user prefers to set this option it must include the filename Incorrect usage export GDBRTC_CONFIG export GDBRTC_CONFIG tmp Correct usage export GDBRTC_CONFIG tmp yet_another_ config export GDBRTC_CONFIG tm
139. a 80 8 Examining Dala k resanni tan eana EO EEEE EEE AEA EES AN E EE A 83 8 1 EXpressSionS ka ei ei erene e E e tha EEE E AEE EEn K EA EES EE RE EEE ETES EEE aent 83 8 2 Program varia ples ninen nee eaan E E eE E E ETE EE EE EEA a ETES 84 S S Arindal akay Soera n e aa a A E EEE aE Ae E EEE TEET ETa Sada enia 85 BA Output TOMA tS neer ea e era Ei E E E E E A EA E EASE 86 8 9 Examining MeMO sotit a e aiaa a EEE A EEEa AE TA E deni ganmaeele 87 8 6 Automat C displaye iire t ariei A EE REE AE TARTERA Tie 89 87 P rit setting Seo A EEEE Rey pale EE EE E A I ev 90 eRe VANS I SEOTY EA E E E N E E 95 8 9 Convenience variable Sieen ei a ie a mag R EE ET AE E REA 96 8 10 Registers Sc cuts seese caste vee gs pone eee EEES o Eear EEEE aan mata ee RRO EEE PERAE EEEE SOET Eee EEREN 98 4 Table of Contents 8 11 Printing Bloating Point Values 41a ciistagtee vhenstovt teat tviete va saeplona ae iortngetccmmaeouteden 99 8 12 Floating point ard Wats ned uits eseri tes tue ies eni AA AE NEES EE air 99 9 Using GDB with Different Languages ssssiseseeseiseesiserstsststtstttittstisteststistrstsstitentistesessrstent 101 9 1 Switching between source languages sss seissssiseiseesessesstretstssestesessesressreesesseseeses 101 9 1 1 List of filename extensions and languages sessesssessesessseisrrseesserssrsersserssese 101 9 1 2 Setting the working language sesssesesssesssrssesseessersresressersrisnesserssrsneeserssese 102
140. a Zannoni Kim Haase Rosario de la Torre Alex McKale Michael Coulter Carl Burch Bharath Chndramohan Diwakar Nag Muthuswami Dennis Handly Subash Babu and Dipshikha Basu provided HP specific information in this manual Cygnus Solutions has sponsored GDB maintenance and much of its development since 1991 Cygnus engineers who have worked on GDB full time include Mark Alexander Jim Blandy Per Bothner Kevin Buettner Edith Epstein Chris Faylor Fred Fish Martin Hunt Jim Ingham John Gilmore Stu Grossman Kung Hsu Jim Kingdon John Metzler Fernando Nasser Georey Noer Dawn Perchik Rich Pixley Zdenek Radouch Keith Seitz Stan Shebs David Taylor and Elena Zannoni In addition Dave Brolley Ian Carmichael Steve Chamberlain Nick Clifton JT Conklin Stan Cox DJ Delorie Ulrich Drepper Frank Eigler Doug Evans Sean Fagan David Henkel Wallace Richard Henderson Jeff Holcomb Jeff Law Jim Lemke Tom Lord Bob Manson Michael Meissner Jason Merrill Catherine Moore Drew Moseley Ken Raeburn Gavin Romig Koch Rob Savoye Jamie Smith Mike Stump Ian Taylor Angela Thomas Michael Tiemann Tom Tromey Ron Unrau Jim Wilson and David Zuhn have made contributions both large and small Contributors to GDB 17 18 1 A Sample GDB Session This chapter describes the most common GDB commands with the help of an example The following topics are discussed e Loading the Executable e Setting the Display Width e Setting Breakpo
141. able command thread enable This command enables the specified thread to run when you issue the continue or step command By default all threads are in the enabled state You can use the thread enable command to reactivate a disabled thread Consider the following example gdb info threadsystem thread 4189 0x7f666da8 in pthread_create_system 0x3d8 from usr lib libpthread 1 2 system thread 4188 worker wptr 0x40004640 at quicksort c 135 1 system thread 4184 0x7f66f728 in _lwp_create 0x10 from usr lib libpthread 1 To disable a thread execute the following command gdb thread disable 1 warning ATTENTION Disabling threads may result in deadlocks in the program Disabling thread 1 To enable a thread execute the following command gdb thread enable 1 Enabling thread 1 14 11 Thread Debugging Support 181 14 11 2 Backtrace Support for Thread Debugging The following commands are available as backtrace support for thread debugging bt thread apply all bt backtrace other thread The bt command provides the stack trace of the current thread that is being executed or the thread that accepts the signal in case of a core file You can use the thread apply all bt command to display the backtrace of all threads The bt command only provides the stack trace of the current thread under execution The backtrace_other_thread command prints the backtrace of all stack frames for a thread with stack pointer SP p
142. ack list arguments command Synopsis stack list arguments show values low frame high frame Display a list of the arguments for the frames between low frame and high frame inclusive If low frame and high frame are not provided list the arguments for the whole call stack The show values argument must have a value of 0 or 1 A value of 0 means that only the names of the arguments are listed a value of 1 means that both names and values of the arguments are printed GDB command GDB does not have an equivalent command gdbtk hasa gdb_get_args command which partially overlaps with the functionality of stack list arguments Example gdb stack list frames done stack frame level 0 addr 0x00010734 func callee4 file devo gdb testsuite gdb mi basics c line 8 frame level 1 addr 0x0001076c func callee3 file devo gdb testsuite gdb mi basics c line 17 frame level 2 addr 0x0001078c func callee2 file devo gdb testsuite gdb mi basics c line 22 frame level 3 addr 0x000107b4 func calleel 342 The GDB MI Interface file devo gdb testsuite gdb mi basics c line 27 frame level 4 addr 0x000107e0 func main file devo gdb testsuite gdb mi basics c line 32 gdb stack list arguments 0 done stack args frame level 0 args frame level 1 args name strarg frame level 2
143. ails on how to do this You can use WDB to debug programs written in Fortran WDB does not distinguish between Fortran 77 and Fortran 90 files WDB provides the following command to control case sensitivity case sensitive on off Other supported features are e Fortran 90 pointers e Structures and unions The default for Fortran is off while for other languages the default is on e Calling functions with integer logical real complex arguments e Intrinsic support 9 4 2 1 Fortran types Fortran types supported 112 Using GDB with Different Languages integer 1 integer 2 integer 4 integer 8 logical 1 logical 2 logical 4 logical 8 byte real 4 real 8 real 16 complex 8 complex 16 character len character len is a user supplied length arrays 9 4 2 2 Fortran operators e allocatable e assumed size assumed shape e adjustable e automatic e explicit shape Array elements are displayed in column major order Use for array member access for example arr i instead of arr i Use set print elements to control the number of elements printed out when specifying a whole array The default is 200 elements or the number of elements of the array whichever is smaller The following Fortran operators are listed here in the order of increasing precedence Assignment w i eat Binary operators Unary operators EN Exponentiation EQ Equal NE Not equal or concatenation ET eps
144. ak enable breakpoint Enable previously disabled breakpoint s GDB command The corresponding GDB command is enable Example gdb break enable 2 done gdb break list done BreakpointTable nr_ rows 1 nr_cols 6 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col_name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alignment 1 col_name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colhdr What body bkpt number 2 type breakpoint disp keep enabled y addr 0x000100d0 func main file hello c line 5 times 0 gdb The break info Command Synopsis break info breakpoint Get information about a single breakpoint GDB command The corresponding GDB command is info break breakpoint 21 5 GDB MI breakpoint table commands 315 Example N A The break insert command Synopsis break insert t h r c condition i ignore count p thread line addr If specified line can be one of e function e filename linenum e filename function e address The possible optional parameters of this command are sae Insert a temporary breakpoint h Insert a hardware breakpoint c condition Make the breakpoint conditional on condition i ignore count
145. akpoint at an instruction without changing the instruction This can be used with the new trap generation provided by SPARClite DSU and some x86 based targets These targets will generate traps when a program accesses some data or instruction address that is assigned to the debug registers However the hardware breakpoint registers can take a limited number of breakpoints For example on the DSU only two data breakpoints can be set at a time and GDB will reject this command if more than two 5 1 Breakpoints 53 54 thbreak args rbreak regex info breakpoints n info break n info watchpoints n Stopping and Continuing are used Delete or disable unused hardware breakpoints before setting new ones see Disabling breakpoints page 58 See Break conditions page 59 Set a hardware assisted breakpoint enabled only for one stop args are the same as for the hbreak command and the breakpoint is set in the same way However like the tbreak command the breakpoint is automatically deleted after the first time your program stops there Also like the hbreak command the breakpoint requires hardware support and some target hardware may not have this support See Disabling breakpoints page 58 See also Break conditions page 59 Set breakpoints on all functions matching the regular expression regex This command sets an unconditional breakpoint on all matches printing a list of all breakpoints it
146. alloc on Itanium or WDB memory check batch mode on Integrity systems e RTC_PROCESS GDBINIT is an optional environment variable used to enable processing of the gdbinit file You can use the gdbinit file to specify path settings such as dir objectdir and pathmap to set the path of the source and object files in case the source or object paths are different than the current directory so that the generated RTC reports display the symbol names and line numbers correctly This feature is optionally enabled only when the RTC_PROCESS GDBINIT environment variable is set to 1 There are limitations on what commands in the gdbinit file If there are erroneous commands inthe gdbinit file the batch RTC session can possibly hang and not produce the expected RTC reports Following are some examples 1 Ifthe q quit command is used the session would hang and finally terminate after approximately 10 mins and not generate any RTC reports It would print the error message Broken synchronization between child parent process 2 Ifany gdb command that would take more processing time is used this would interfere with the assumptions of RTC and the session may hang and print the error message Broken synchronization between child parent process 14 10 5 3 Example for Batch Mode RTC This section illustrates examples of batch mode RTC on HP 9000 and Integrity Systems e Example for Batch Mode RTC of a PA RISC 32 bit Executable 1 Compile the source fi
147. ame 3 This is away of removing one word from the stack on machines where stacks grow downward in memory most machines nowadays This assumes that the innermost stack frame is selected setting sp is not allowed when other stack frames are selected To pop entire frames off the stack regardless of machine architecture use return see Returning from a function page 121 Examining Data Some registers have distinct raw and virtual data formats This means that the data format in which the register contents are saved by the operating system is not the same one that your program normally sees For example the registers of the 68881 floating point coprocessor are always saved in extended raw format but all C programs expect to work with double virtual format In such cases GDB normally works with the virtual format only the format that makes sense for your program but the info registers command prints the data in both formats Normally register values are relative to the selected stack frame see Selecting a frame page 73 This means that you get the value that the register would contain if all stack frames farther in were exited and their saved registers restored In order to see the true contents of hardware registers you must select the innermost frame with frame 0 However GDB must deduce where registers are saved from the machine code generated by your compiler If some registers are not saved
148. andles the VPATH feature 366 Installing GDB GNU make does running make in each of these directories builds the gdb program specified there To build gdb in a separate directory run configure with the srcdir option to specify where to find the source You also need to specify a path to find configure itself from your working directory If the path to configure would be the same as the argument to srcdir you can leave out the srcdir option it is assumed For example with version gdb 199991101 you can build GDB in a separate directory for a Sun 4 like this cd gdb gdb 199991101 mkdir gdb sun4 cd gdb sun4 gdb gdb 199991101 configure sun4 make When configure builds a configuration using a remote source directory it creates a tree for the binaries with the same structure and using the same names as the tree under the source directory In the example you d nd the Sun 4 library libiberty a in the directory gdb sun4 libiberty and GDB itself in gdb sun4 gdb One popular reason to build several GDB configurations in separate directories is to configure GDB for cross compiling where GDB runs on one machine the host while debugging programs that run on another machine the target You specify a cross debugging target by giving the target target option to configure When you run make to build a program or library you must run it in a configured directory whatever directory you were in when
149. ands to display macro definitions 14 9 Debugging Macros 153 show macro macro name or info macro macro name Displays the macro definition source file name and the line number For example gdb info macro VAR2 Defined at scope c 21 define VAR2 201 macro expand macro name Expands the macro and the parameters in the macro If there are any parameters in the macro they are substituted in the macro definition when the definition is displayed For example define YY 6 define MAC 67 YY gdb gdb macro expand MAC expands to 67 6 e Evaluating Macros HP WDB enables you to evaluate a macro and display the output You can evaluate the macro by using the commonly used gdb commands for evaluating and displaying expressions such as print HP WDB supports the evaluation of macros with variables constants complex algebraic expressions involving variables nested macros and function calls HP WDB does not support the evaluation of macros with multiple statements in the macro definitions or the evaluation of macros with stringifying and pasting tokens in the macro definitions 14 9 1 1 Compiler Options to Enable Macro Debugging To enable macro debugging the program must be compiled with the macro_debug all none ref compiler option Additionally the program must be compiled with one of the g options g g0 or g1 to enable macro debugging For example cc g macro_debug all o sample sample c The fol
150. ane with logical focus is resized When you increase the height of a pane the height of the Command pane is decreased by the same amount and vice versa The height of any other panes remains unchanged For example the command wh src 3 increases the size of the source pane and decreases the size of the command pane by 3 lines To nd out the current sizes of all panes use the info win command For example if you have a split screen layout the command output might be as follows gdb i win SRC 8 lines REGS 8 lines CMD 8 lines If you use the mouse or window menus to resize the terminal window during a debugging session the window remains the same size it was when you started To change the window size you must exit the debugger and restart it 15 9 Refreshing and updating the window If the screen display is disrupted for some reason use the refresh command ref to restore the windows to their previous state ref If you use stack navigation commands such as up down and frame to change your source location and you want to return the display to the current point of execution use the update command upd upd 252 The HP UX Terminal User Interface 16 XDB to WDB Transition Guide This transition aid is designed for XDB users who are learning WDB an HP supported version of the industry standard GDB debugger Select one of these lists for a table that shows WDB equivalents for many common XDB commands and other f
151. angtools lib hpux32 librtc so lt executable gt For 64 bit IPF applications LD_PRELOAD opt langtools lib hpux64 librtc so lt executable gt o ri or 32 bit PA applications LD _PRELOAD opt langtools lib librtc sl lt executable gt For 64 bit PA applications D PRELOAD opt langtools lib pa20_ 64 librtc sl lt executable gt i A NOTE To attach and nd leaks for PA 32 applications from the startup the environment variable RTC_INIT should be set to on in addition to preloading the librtc s1 so library before starting the application as follows LD PRELOAD opt langtools lib librtc sl RTC_INIT on lt application gt If RTC_INIT is turned on librtc starts recording heap information for PA32 process by default Hence you must set this environment variable only when it is required and you must not export this environment variable for shell 172 HP UX Configuration Specific Information 2 Run the program 3 Start a debugging session as follows gdb leaks lt executable name gt lt process id gt 4 Useinfo heapand info leaks commands to obtain a memory analysis report of the application EY NOTE From HP WDB 5 7 onwards the archive version of the run time check library librtc a is not available You must use the shared version of the library librtc sl so instead 14 10 7 Configuring memory debugging settings The following configuration settings are supported to control the
152. anguage Current language for expression evaluation Sline No equivalent Current source line number malloc No equivalent Debugger memory allocation bytes Sprint No equivalent Display mode for character data Sregname S regname Hardware registers result Use n value history number Return value of last command line assigned to the desired result procedure call signal No equivalent Current child procedure signal number step No equivalent Number of instructions debugger will step in non debuggable procedures before free running Svar var Dene or use special variable convenience variable 16 6 XDB special variables and HP WDB equivalents 269 16 7 XDB variable identifiers and HP WDB equivalents Table 16 20 Variable Identifiers XDB Variable Identifier WDB Equivalent Meaning var var Search for var class class Search class for var bug not yet class proc class var proc var Search proc for var static variables only class proc depth class No equivalent Search proc for depth on stack dot Empty string for example pis Shorthand for last thing you the equivalent of p looked at var or var var to distinguish a global from Search for global variable only a local variable with same name 16 8 Alphabetical lists of XDB commands and HP WDB equivalents e Table 16 21 page 270 e Table 16 22 page 271 e Table 16 23 page 272 e Table 16 24 page 273 e
153. annotation occurs right before GDB responds to an interrupt Z Zerror This annotation occurs right before GDB responds to an error Quit and error annotations indicate that any annotations which GDB was in the middle of may end abruptly For example if a value history begin annotation is followed by aerror one cannot expect to receive the matching value history end One cannot expect not to receive it either however an error annotation does not necessarily mean that GDB is immediately returning all the way to the top level A quit or error annotation may be preceded by Z Zerror begin Any output between that and the quit or error annotation is the error message Warning messages are not yet annotated 20 8 Information on breakpoints The output from the info breakpoints command is annotated as follows Z Zbreakpoints headers header entry Z Zbreakpoints table 302 GDB Annotations where header entry has the same syntax as an entry see below but instead of containing data it contains strings which are intended to convey the meaning of each field to the user This is followed by any number of entries If a field does not apply for this entry it is omitted Fields may contain trailing whitespace Each entry consists of Z Zrecord z zfield 0 number z zfield 1 type z zfield 2 disposition z zfield 3 enable z zfield 4 address z zfield 5 what z zfield 6 frame z zfield 7 condition
154. are allocated in strdup in link the list in main at test c 13 in start at test c255 14 10 5 Debugging Memory in Batch Mode HP WDB supports batch mode memory leak detection also called batch Run Time Checking Batch RTC Most of the memory debugging features supported in interactive mode are also supported in batch mode A NOTE shell script The batch mode commands may not always work when invoked through a 14 10 5 1 Setting Configuration Options for Batch Mode You can specify the batch mode configuration through a configuration file called rtcconfig The configuration file supports these variables check_free on off or set heap check free lt on off gt check _heap heap on off or set heap check lt on off gt check _leaks leaks on off or set heap check leaks lt on off gt check_string on off or set heap check string lt on off gt check_bounds bounds on off or set heap check bounds lt on off gt files lt filel file2 fileN gt 164 HP UX Configuration Specific Information Enables detection of multiple incorrect free of memory Enables heap profiling Enables leak detection Enables detection for writing out of boundary for strcpy strncpy memcpy memccpy memset memmove bzero bcopy Enables checking of bounds corruption Specifies the executables for which memory leak detection is enabled If files option is not specified after setting BATCH _RTC on
155. are useful for debugging programs in any language set print address set GDB prints memory addresses showing the location print address on of stack traces structure values pointer values breakpoints and so forth even when it also displays the contents of those addresses The default is on For example this is what a stack frame display looks like with set print address on gdb f 0 set_quotes lq 0x34c78 lt lt rq 0x34c88 S gt at input c 530 530 if lquote def _lquote Examining Data set print address off show print address Do not print addresses when displaying their contents For example this is the same stack frame displayed with set print address off gdb set print addr off gdb f 0 set_quotes lq lt lt rq gt gt at input c 530 530 if lquote def _lquote Youcanuse set print address off to eliminate all machine dependent displays from the GDB interface For example with print address off you should get the same text for backtraces on all machines whether or not they involve pointer arguments Show whether or not addresses are to be printed When GDB prints a symbolic address it normally prints the closest previous symbol plus an offset If that symbol does not uniquely identify the address for example it is a name whose scope is a single source file you may need to clarify it One way to do this is with info line Forexample info line 0x4537 Alternately you can s
156. as follows chatr dbg enable lt executable gt This step is not required on Integrity systems To explicitly preload the 1ibrtc runtime library and start the target application enter one of the following commands For 32 bit IPF applications iD_PRELOAD opt langtools lib hpux32 librtc so lt executable gt For 64 bit IPF applications iD_PRELOAD opt langtools lib hpux64 librtc so lt executable gt For 32 bit PA applications 166 HP UX Configuration Specific Information LD PRELOAD opt langtools lib librtc sl lt executable gt For 64 bit IPF applications LD_PRELOAD opt langtools lib pa20_64 librtc sl lt executable gt IfLD_PRELOADand chatr rtcareused to preload the librtc runtime library the librtc runtime library is loaded from the path specified by LD PRELOAD A NOTE Batch Mode RTC displays one of the following errors and causes the program to temporarily hang if the version of WDB and librtc s1 so do not match or if WDB is not available on the system opt langtools bin gdb unrecognized option brtc Use opt langtools bin gdb help for a complete list of options OR execl failed Cannot print RTC info No such file or directory This error does not occur under normal usage where WDB or librtc s1 so is used from the default location at opt langtools However this error occurs if GDB_SERVER and or LIBRTC_SERVER are set to a mismatched version of
157. assemble the whole main function Line 32 is part of main data disassemble f basics c 1 32 0 done asm_insns address 0x000107be func name main offset 0 inst save sp 112 sp address 0x000107c0 func name main offset 4 inst mov 2 00 address 0x000107c4 func name main offset 8 inst sethi hi 0x11800 02 Eeay address 0x0001081c func name main offse address 0x00010820 func name main offse 96 inst ret 100 inst restore gdb Disassemble 3 instructions from the start of main gdb data disassemble f basics c l 32 n 3 0 done asm_insns address 0x000107be func name main offset 0 inst save sp 112 sp address 0x000107c0 func name main offset 4 inst mov 2 00 address 0x000107c4 func name main offset 8 inst sethi hi 0x11800 02 gdb Disassemble 3 instructions from the start of main in mixed mode gdb data disassemble f basics c l 32 n 3 1 21 6 GDB MI Data manipulation 321 done asm_insns src_and_asm_line line 31 file kwikemart marge ezannoni flathead dev devo gdb testsuite gdb mi basics c line asm_insn address 0x000107be func name main offset 0 inst save sp 112 sp src_and_asm_line line 32 file kwikemart marge ezannoni flathead dev devo gdb testsuite gdb mi basics c line asm_insn address 0x000107c0 func nam
158. assisted breakpoints and watchpoints and then continue 5 2 Continuing and stepping 64 Continuing means resuming program execution until your program completes normally In contrast stepping means executing just one more step of your program where step may mean either one line of source code or one machine instruction depending on what particular command you use Either when continuing or when stepping your program may stop even sooner due to a breakpoint or a signal If it stops due to a signal you may want to use handle or use signal 0 to resume execution See Signals page 67 continue ignore count c Resume program execution at the address where ignore count fg your program last stopped any breakpoints set at ignore count that address are bypassed The optional argument ignore count allows you to specify a further number of times to ignore a breakpoint at this location its effect is like that of ignore see Break conditions page 59 The argument ignore count is meaningful only when your program stopped due to a breakpoint At other times the argument to continue is ignored The synonyms c and fg for foreground as the debugged program is deemed to be the foreground program are provided purely for convenience and have exactly the same behavior as continue To resume execution at a different place you can use return see Returning from a function page 121 to go back to t
159. at see Output formats page 86 print print f Ifyou omit expr GDB displays the last value again from the value history see Value history page 95 This allows you to conveniently inspect the same value in an alternative format A more low level way of examining data is with the x command It examines data in memory at a specified address and prints it in a specified format See Examining memory page 87 If you are interested in information about types or about how the fields of a struct or a class are declared use the ptype exp command rather than print See Chapter 10 page 115 8 1 Expressions print and many other GDB commands accept an expression and compute its value Any kind of constant variable or operator defined by the programming language you are using is valid in an expression in GDB This includes conditional expressions function calls casts and string constants It unfortunately does not include symbols defined by preprocessor define commands GDB supports array constants in expressions input by the user The syntax is element element For example you can use the command print 1 2 3 to build up an array in memory that calls malloc in the target program Because C is so widespread most of the expressions shown in examples in this manual are in C See Chapter 9 page 101 for information on how to use expressions in other languages In this section we discuss operators that you
160. ate of debugger and kinds program 16 1 8 Job control commands The following table lists the XDB and equivalent WDB commands for controlling program execution Table 16 7 Job control commands XDB Command WDB Equivalent Meaning c c continue Continue from breakpoint ignoring any pending signal c location until location Continue from breakpoint ignoring any pending signal set temporary breakpoint at location C c continue Continue allowing any pending signal C location until location Continue allowing any pending signal set temporary breakpoint at location g line g line with xdb go Go to line in current procedure line tb line followed by jump line g label No equivalent Go to label in current procedure 16 1 By function lists of XDB commands and HP WDB equivalents 259 Table 16 7 Job control commands continued XDB Command WDB Equivalent Meaning g lines g lines with Go forward or back given lines xdb go lines tb lines followed by jump lines g g with xdb go Go forward or back 1 line 1 tb 1 followed by jump 1 k k Detach and terminate target r arguments r arguments Run with last arguments or with new arguments R R with xdb r Rerun with no arguments s s si Single step into procedures si step by instruction s number s number si number Single step number steps int
161. ault threshold is 100 megabytes 12 1 Commands to specify files 129 show auto solib add Display the current autoloading size threshold in megabytes 12 2 Specifying shared library locations On HP UX when the shared libraries your program uses are in a different directory than the path specified in the source or object files specify the correct files to use with one of two environment variables GDB_SHLIB_PATH Set this variable to a colon separated list of directory path names where the desired shared libraries reside GDB searches specified list of directories for shared libraries before searching the default system directories GDB_SHLIB_ROOT Set this variable to point to the root of the library in which the desired libraries reside A NOTE If you set both the GDB_SHLIB_PATH and GDB_SHLIB ROOT environment variables the GDB_SHLIB_ PATH behavior overrides GDB SHLIB ROOT These environment variables are useful when you are analyzing core files on a system other than the one that produced the core file For example if you want GDB to search for libraries in home debugger 1ib and tmp 1ib before searching the default system directories for libraries you can use this setting GDB_SHLIB PATH home debugger lib tmp lib With this setting GDB searches the directories in the order specified until it finds a library with the correct name In this example if GDB encounters a library by the name of us
162. base name alone as long as file names are unique and the appropriate dir commands have been executed Pressing the Prompt softkey takes you to the command prompt and also updates the source window so that the cursor remains where the program is stopped 14 31 9 Editing source files To edit a file kill the process then click the Edit button If you do not kill the process the source file and binaries can get out of sync 14 31 10 Editing the command line and command line history Visual Interface for WDB preserves the entire session s transactions so you can browse through these at any time To edit the command line press ESC to enter vi mode and then use vi commands You can recall previous commands in history by using jk P N Complete command lines using TAB 14 31 11 Saving the contents of a debugging session to a file You can save the contents of the current debugging session including debugger input output and program input output to a file 14 31 Visual Interface for WDB 237 To save a session to a file 1 Right click an empty region of the source or debugger pane 2 Choose Save Session to vdb pid from the pop up menu The debugger writes the input and output to a file whose name ends in the pid of the debugger If you save the session more than once the new transactions are appended to the file 14 32 Support for ddd GDB works with ddd the free GDB GUI shell available at http mumm ibr cs tu bs de While
163. bject file format specifies a fixed address load does not repeat if you press RET again after using it load does not repeat if you press RET again after using it 13 3 Choosing target byte order Some types of processors such as the MIPS PowerPC and Hitachi SH offer the ability to run either big endian or little endian byte orders Usually the executable or symbol will include a bit to designate the endian ness and you will not need to worry about which to use However you can adjust the processor byte order manually using one of the following commands 13 3 Choosing target byte order 135 set endian big Instruct GDB to assume the target is big endian set endian little Instruct GDB to assume the target is little endian set endian auto Instruct GDB to use the byte order associated with the executable show endian Display GDB s current idea of the target byte order Note that these commands merely adjust interpretation of symbolic data on the host and that they have absolutely no effect on the target system 136 Specifying a Debugging Target 14 HP UX Configuration Specitic Information While nearly all GDB commands are available for all native and cross versions of the debugger there are some exceptions This chapter describes features commands and enhancements available only on HP UX 14 1 Summary of HP Enhancements to GDB WDB provides the following features in addition to the standard GDB features Support for de
164. ble resolution for i is A AB ABC ABCD the debugger prints out the name of the symbol and its value If however a global i exists the debugger displays a menu from which to choose 1 i 2 A AB ABC ABCD i gt Setting breakpoints on functions works in the same way The debugger also allows semi qualified names For example if you stop in a function in namespace B which is nested in namespace A and namespace A has an int i you can use print B i to display the value of A B To disable namespace support use the command gdb set namespaces enabled off 14 25 6 Command for evaluating the address of an expression The watch_target command takes an expression as an argument evaluates it to an address and watches the target of that address For example gdb watch _ target current frame This is equivalent to executing gdb print current frame 1 struct frame_info Ox7fdf78 gdb watch struct frame_info Ox7f df78 14 26 Viewing Wide Character Strings HP WDB print command can print wide characters and wide character strings of the type wchar_t The user must use the W option of the print command to print wide characters and wide character strings print W lt wide char symbol name gt 14 26 Viewing Wide Character Strings 223 14 27 Support for output logging The Visual Interface for HP WDB terminal user interface TUI mode supports the command log logfile name that saves the content of a s
165. bles in HP C sesssesssesssssesssessrssessserssessesserssesees 222 14 25 5 Support for debugging namespaces s sssssssessessssetsersesrisssesressssensessest ees 222 14 25 6 Command for evaluating the address of an exPresSiON cccecceeeseereeeees 223 14 26 Viewing Wide Character Strines si i 0idenciatetnaceassia hath gaat ear uiaanatess 223 14 27 Support for output LOS PIN issii siei sienai niai ai rrei iik riei aae 224 14 27 1 Support for dumping array in an ASCII 6 wii ciise vsadecsviehivicarsvndecetvcrsemsnevdes 224 14 27 2 Support for Fortran array SU CES eiecssstyacsasesstesnsysadevtucsvenesaets wendesizownndy sa tensnennneeeds 225 14 27 39 Displaying Cnumel ators iva cistern areara AEE EE esti ei Ea i 225 14 27 4 Support for debugging typedefs sesssessssessseississeeseesseesrsreessersresresseessesees 225 14 27 5 Support for steplast command for C and CH ssssssssesssessessessserssrsresserssesees 225 14 28 Getting information from a non debug executable sssssesssessssseessersrssesrsersseses 226 14 29 Debugging optimized COM Gy sx 5 jee spesves Sec tiveseeyieayiivis eiaa ie iiaiai 227 14 29 1 Debugging Optimized Code at Various Optimization Levels 064 229 IE ee Fed Bad Wess aat i1 EE S te Ree CS ET ANTS 229 14 29 1 2 027 03 04 LPO cccccccecceccsescccccanseseceneseccscaceseesenetecdecansssecseetececeansseess 229 14 30 DEDUS PINS with ARIES rennene eeen E exp ite Oaai eE EAT
166. blocks and number of instances info leaks filename info leak leaknumber set heap check block size num bytes set heap check heap size num size min heap size set heap check watch address set heap check null check N random set heap check null check size N catch nomem set heap check free on off set heap check string on off Writes the complete leak report output to the specified file Produces detailed information on the specified leak including the allocation call stack Instructs WDB to stop the program whenever it tries to allocate a block larger than num bytes in size Instructs WDB to stop the program whenever it tries to increase the program heap by at least num bytes This option reports the heap allocations that exceed the specified number lt num gt of bytes based on the cumulative number of bytes that are allocated at each call site which is inclusive of multiple calls to malloc at a particular call site Stops the program whenever a block at a specified address is allocated or deal located Force malloc to return NULL after N or random number of invocations of malloc Use set heap check random range Nand set heap check seed value Nto define the seed value and range for random number calculation Useful for simulating out of memory situations Force malloc to return NULL after N bytes have been allocated by the program Allows the user to get control of an out of memory
167. breakpoint of its own but it does not change the state of your other breakpoints see Continuing and stepping page 64 5 1 5 Break conditions The simplest sort of breakpoint breaks every time your program reaches a specified place You can also specify a condition for a breakpoint A condition is just a Boolean expression in your programming language see Expressions page 83 A breakpoint with a condition evaluates the expression each time your program reaches it and your program stops only if the condition is true This is the converse of using assertions for program validation in that situation you want to stop when the assertion is violated that is when the condition is false In C if you want to test an assertion expressed by the condition assert you should set the condition assert on the appropriate breakpoint Conditions are also accepted for watchpoints you may not need them since a watchpoint is inspecting the value of an expression anyhow but it might be simpler 5 1 Breakpoints 59 60 say to just set a watchpoint on a variable name and specify a condition that tests whether the new value is an interesting one Break conditions can have side effects and may even call functions in your program This can be useful for example to activate functions that log program progress or to use your own print functions to format special data structures The effects are completely predictable unless there i
168. bugging memory problems Support for heap usage reporting The min heap size lt num gt option for set heap check command reports the heap allocations that exceed the specified number lt num gt of bytes based on the cumulative number of bytes that are allocated at each call site which is inclusive of multiple calls to malloc at a particular call site Heap checking commands info heap high memand set heap check high mem count X_ number Commands which exit info heap process and info heap arena WDB supports the check compiler option on Integrity systems to invoke batch RTC to determine runtime memory problems Enhanced batch RTC support for better reporting and options have replaced old ones RTC heap corruption checks for calls to strcpy memset and memcpy have been added Support for memory checking analysis for user defined memory management routines High water mark records the number of times the brk value changes Heap analysis on programs with pending signals using the info leak command Commands info module ADDRESS show envvars and info corruption Command line option pid or p to attach to an existing process Support for debugging kernel threads and user threads Support for enabling and disabling threads Thread debugging commands set thread check on off info thread thread id info mutex mutex id info condvar condvar id and info rwlock rwlock id Enhanced thread debugging options fo
169. bytes must be allocated at the beginning and end of each block To stop a program whenever a block at a specified address is allocated or deallocated use the command set heap check watch address You can use this to debug situations such as multiple free calls to the same block Limitation This is not supported in batch mode debugging 14 10 8 4 Scramble previous memory contents at malloc free calls DELY A WDB enables you to potentially expose latent memory access defects with the command InInteractive debugging mode set heap check scramble on off In batch mode debugging scramble blocks on off When this setting is turned on any time a memory block is allocated or deallocated WDB scrambles the space and overwrites it with a specific pattern This change to the memory contents increases the chance that erroneous behaviors will cause the program to fail Examples of such behavior include attempting to access space that is freed or depending on initial values of malloc blocks You can now look at the stack trace to understand where and how the problem occurred NOTE Turning on scrambling slows down the program slightly because at every malloc and free call the space involved must be overwritten 14 10 8 5 Detect dangling pointers and dangling blocks A pointer is a Dangling pointer if the block of memory it points to has been freed by the application The block is called Dangling Block T
170. c Set breakpoints on overloaded functions outside a class bpo class proc b class proc Set breakpoints on overloaded functions in a class bt depth No equivalent Set trace breakpoint at procedure at specified depth on program stack bt proc b proc commands bnum Set trace breakpoint at proc finish c end bu depth bu depth with xdb Set up level breakpoint The finish command is equivalent to the sequence bu c db to continue out of the current routine bx depth bx depth with xdb Set a breakpoint at procedure exit The following table lists the XDB and equivalent WDB commands for changing the breakpoint status Table 16 11 Overall breakpoint commands XDB Command WDB Equivalent ab number enable number ab enable Meaning Activate suspended breakpoint of the given number Activate all suspended break points ab shared library No equivalent Activate suspended breakpoints in named shared library 262 XDB to WDB Transition Guide Table 16 11 Overall breakpoint commands continued XDB Command WDB Equivalent number expr be number expr with xdb ignorenumber expr within a commands list Meaning Set a breakpoint count 16 2 4 All procedures breakpoint commands db clear Delete breakpoint at current line db number delete number Delete breakpoint of the given number db delete Delete all breakpoints sb number disable number Suspend brea
171. c linux gnu sh config sub alpha linux alpha unknown linux gnu sh config sub hp9k700 hppal 1 hp hpux sh config sub sun4 sparc sun sunos4 1 1 sh config sub sun3 m68k sun sunos4 1 1 sh config sub i986v Invalid configuration i986v machine i986v not recognized config sub is also distributed in the GDB source directory gdb gdb 199991101 for version gdb 199991101 A 3 configure options Here is asummary of the configure options and arguments that are most often useful for building GDB configure also has several other options not listed here See Info file configure info or the node What Configure Does for a full explanation of configure configure help prefix dir exec prefix dir srcedir dirname norecursion rm target target host You may introduce options with a single rather than if you prefer but you may abbreviate option names if you use help Display a quick summary of how to invoke configure prefix dir Configure the source to install programs and files under directory dir exec prefix dir Configure the source to install programs under directory dir srcdir dirname Warning using this option requires gnu make or another make that implements the VPATH feature Use this option to make configurations in directories separate from the GDB source directories Among other things you can use this to build or maintain several configurations simultaneously
172. c output token async output status async output token async output notify async output token async output async output async class result nl result class done running connected error exit async class stopped others where others will be added depending on the needs this is still in development result variable value variable string 308 The GDB MI Interface value const tuple list const c string tuple gt result result list value value result result stream record console stream output target stream output log stream output console stream output an c string target stream output c string log stream output amp c string nl CR CR LF token any sequence of digits Notes All output sequences end in a single line containing a period The token is from the corresponding request If an execution command is interrupted by the exec interrupt command the token associated with the stopped message is the one of the original execution command not the one of the interrupt command status async output contains on going status information about the progress of a slow operation It can be discarded All status output is prefixed by exec async output contains asynchronous state change on the target stopped started disappeared All async output is prefixed by notify a
173. c sl HP WDB does not support debugging of programs that link with the archive version of the standard C library libc a or the core library libcl a The programs must be linked with libc s1l The advanced thread debugging commands work only if set thread check is set to on For PA RISC 32 bit applications the dynamic library path look up must be enabled for advanced thread debugging To enable dynamic library path look up for advanced thread debugging enter the following command at HP UX prompt chatr s enable lt PA32 bitApp gt This command automatically enables dynamic library path look up No additional environmental variables are required to be set 14 11 3 2 Enabling and Disabling Advanced Thread Debugging Features HP WDB 5 6 and later versions of the debugger provide advanced thread debugging features for debugging multi threaded applications running on 11i v2 or 11i v3 These 14 11 Thread Debugging Support 183 features are available as options to the set thread check command The syntax for the set thread check command is as follows set thread check on off option on off option num The set thread check on off command enables or disables advanced thread debugging This feature is off by default The set thread check on off command must be enabled prior to running the application under the debugger to force the underlying runtime system to collect information on pthread primitives The advanced th
174. c8 Ox32cc 0x32d0 0x32d4 0x32d8 0x32dc 0x32e0 End of lt main 204 gt lt main 208 gt lt main 212 gt lt main 216 gt lt main 220 gt lt main 224 gt lt main 228 gt lt main 232 gt code from 0x32c4 to 0x32e4 addil 0 dp ldw 0x22c sr0 rl1 r26 ldil 0x3000 r31 ble 0x3f8 sr4 r31 ldo 0 r31 rp addil 0x800 dp ldo 0x588 r1 r26 ldil 0x3000 r31 assembler dump Some architectures have more than one commonly used set of instruction mnemonics or other syntax set disassembly flavor Select the instruction set to use when instruction set disassembling the program via the disassemble or x i commands Currently this command is only defined for the Intel x86 family You can set inst ruction set to either intel or att The default is att the AT amp T flavor used by default by Unix assemblers for x86 based targets 7 4 Source and machine code 81 82 8 Examining Data The usual way to examine data in your program is with the print command abbreviated p or its synonym inspect It evaluates and prints the value of an expression of the language your program is written in see Chapter 9 page 101 The following forms of print command are supported print expr expr is an expression in the source language By default the print f expr value of expr is printed in a format appropriate to its data type you can choose a different format by specifying f where f is a letter specifying the form
175. ce of an inline function It also enables the inline debugging feature All instances of the inline function are displayed separately with individual breakpoint occurrences You can set or delete individual breakpoints on a specific instance of an inline function without modifying the breakpoints on other instances of the inline function You must enter this command before attaching the debugger to the application Limitations e The inline breakpoint features are not available for programs that are com piled with O2 optimization level and above e The inline breakpoint features can degrade performance of the application that is being debugged You can explicitly disable the breakpoint features when the features are not required and continue to use other inline debugging features such as step and next 14 8 2 1 Debugging Inline Functions in Integrity Systems To debug inline functions in Integrity systems complete the following steps 1 The application must be compiled with the g option for inline debugging No additional options are required For example opt aCC bin aCC g test c 2 Inline debugging without the breakpoint feature is enabled by default You can modify the inline debugging settings by toggling the options for the set inline debug command e To enable inline debugging without inline breakpoint support enter either of the following commands gdb set inline debug on or gdb inline on e To set and modify breakpoi
176. cedure main Line 32 pe 0x3524 gdb la asm 15 5 Changing pane focus 249 gdb la split gdb la regs gdb la src gdb la regs gdb foc next Focus set to REGS window 15 6 Scrolling panes To scroll within a pane you can use the arrow keys or the Page Up and Page Down keys on some keyboards these are Prev and Next You can also use the following commands num_lines Vertically scroll the pane forward or backward win name or with no arguments scrolls the pane forward or backward one page Use num_lines to specify how many lines to scroll the pane Use win_name to specify a pane other than the one with logical focus lt gt num_char Horizontally scroll the pane left lt or right gt win name the specified number of characters If you do not specify num_char the pane is scrolled one character Note that a space is required between the lt or gt and the number To scroll the command pane use the scroll bars on the terminal pane 15 7 Changing the register display To look at the floating point or special registers instead of the general registers and then to return to the general registers you can use the following XDB commands fr display fregs Display the floating point registers sr display sregs Display the special registers gr display gregs Display the general registers For example if you use the fr command the window looks like this flags
177. cessor state even when predicated false In such cases the debugger stops at the instructions irrespective of the predicate value of the instructions Assembly and low level programmers who require the old behavior of the debugger to stop at the instructions irrespective of the predicate value of these instructions can explicitly turn o this feature To explicitly turn o this feature enter the following command at the gdb prompt gdb set no predication handling The following limitations apply when debugging optimized code e Support for high level loop transformations such as modulo scheduled loops or LNO optimized loop nests is limited This limited support includes all loop optimizations that are enabled at 03 and above and some loop optimizations at 02 or O e Debug support for local aggregates and arrays is limited e Complete debug support for inlined subroutines is not available e Values that are not at the current code location will be reported as being unavailable even if these values can be computed from some other values that are available e Step operations may include occasional backwards steps because of the re ordered code during optimization e The program stops at asynchronous signal stops even if the reported instruction is predicated false Complete support is available for debugging at the assembly language level Stepping by instructions stepi nexti steps as expected and reports the associated source li
178. ch to such a process Attaching to process lt pid gt failed Hint Check if this process is already being traced by another gdb or other trace tools like caliper and tusc Hint Check whether program is on an NFS mounted file system If so you will need to mount the file system with the nointr option with mount 1 or make a local copy of the program to resolve this problem 14 4 HP UX targets On HP UX systems GDB has been configured to support debugging of processes running on the PA RISC and Itanium architectures This means that the only possible targets are e An executable that has been compiled and linked to run on HP UX This includes binaries that have been marked as SHMEM_MAGIC e A live HP UX process either started by WDB with the run command or started outside of WDB and attached to with the attach command e A core file generated by an HP UX process that previously aborted execution GDB on HP UX has not been configured to support remote debugging or to support programs running on other platforms WDB can only debug C programs compiled with HP aC the ANSI compatible C compiler 14 5 Support for Alternate root HP WDB supports alternate root functionality which is helpful when you do not want to use the system installed HP WDB or its components The environment variable WDB_ROOT specifies the alternate root for HP WDB You must specify a structure similar to the default opt langtools used for
179. chpoint goes out of scope it is deleted break watch j done wpt number 2 exp j gdb break list done BreakpointTable nr_rows 2 nr_cols 6 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col _name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alinment 1 col_name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colhdr What body bkpt number 1 type breakpoint disp keep enabled y addr 0x00029b4 func call file hello c line 9 times 1 bkpt number 2 type wathpoint disp keep enabled y addr what j times 0 gdb exec continue running gdb stopped reason watchpoint trigger wpot number 2 exp j value old 0 ne 17 thread id 1 frame addr 0x000029be func call args file hello c line 10 gdb break list done BreakpointTable nr_rows 2 nr_cols 6 hdr width 3 alignment 1 col _name number colhdr Num width 14 alignment 1 col_name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alinment 1 col _name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colhdr What body bkpt number 1 type breakpoint disp keep enabled y addr 0x00029b4 func call file hello c
180. control z characters and the name of the annotation If there is no additional information associated with this annotation the name of the annotation is followed immediately by a newline If there is additional information the name of the annotation is followed by a space the additional information and a newline The additional information cannot contain newline characters Any output not beginning with a newline and two control z characters denotes literal output from GDB Currently there is no need for GDB to output a newline followed by two control z characters but if there was such a need the annotations could be extended with an escape annotation which means those three characters as output A simple example of starting up GDB with annotations is gdb annotate 2 GNU GDB 5 0 Copyright 2000 Free Software Foundation Inc GDB is free software covered by the GNU General Public License and you are welcome to change it and or distribute copies of it under certain conditions Type show copying to see the conditions There is absolutely no warranty for GDB Type show warranty for details This GDB was configured as sparc sun sunos4 1 3 Z Zpre prompt gdb Z Zprompt quit Z Zpost prompt Here quit is input to GDB the rest is output from GDB The three lines beginning AZZ where Z denotes a control z character are annotations the rest is output from GDB 20 2 The server prefix To
181. core image file of a process running under the debugger in the middle of execution and saves it in the file named lt core filename gt The dumpcore command with no arguments saves the core image for the current process being debugged in the file named core lt pid gt where pid is the process ID number 202 HP UX Configuration Specific Information To analyze this core file with HP WDB on HP UX 11i version 2 you must do the following e When starting from HP WDB command line gdb core file core pid core filename e When starting from shell prompt gdb core a out core pid core filename 14 15 4 Support for display of run time type information A HP WDB enables you to view the run time type information for C polymorphic object info rtti address This command displays run time type information for C polymorphic object The input to this command is address of the C polymorphic object GDB displays the demangled type name as output NOTE This command is supported only on Integrity systems Sample Output gdb info rtti lt address gt RTTI lt run time type class name gt 14 16 Printing the Execution Path Entries for the Current Frame or Thread HP WDB 5 7 and later versions of the debugger enable you to print the execution path entries in the current frame or the current thread for programs running on Integrity systems This feature enables the display of the execution path taken across branched m
182. cs sees sertocvesavaseessedesiatieeniedte aa i aeS S Ea eE aG KSEE E Een SRU 35 4 Running Programs Under GDB sesssissisesssiiststtetttsttstts ttet testte ttet tE StS EEEE EEEE ESSEE E EEEE Eenes Etenee enee 39 4 1 Compiling f r de uggi g niecne E EEE iE E ER EE EE EE 39 AD Starine your proptan iscr orreri nesat ance anita ee TERESE ee 39 4 3 Arguments To Your Progra s sredio ed pete e Seay weiss Reade E EEEE E SEEE E 41 A Ay Program ENVirONMEN ts seare e aE EEES o EER SETE OEE ETERS E EES 41 45 Working directory orii iorn anaa E E EE ER AE EET E A Eae 43 4 6 Program Input and Output sssssessessseessisessserssissssserssrssreseenseensesenserssesressernseenesserssets 43 4 7 Debugging a Running ProlesSSassiinssrsniiinaiei nania iaiia 44 48 Killing the child Process emoi oaae eeaeee a a aeaa ig 45 Table of Contents 3 4 9 Debugging programs with multiple threads 0 cccceceescesssecessceeeseseeessescsseeeeseees 46 4 10 Debugging programs with multiple processes 1 ccccien ctieduek ine dcaenaeh 49 5 Stopping and Snares se te ee aS Aa a es tad ek taal oe at eee ieee al nae Se 51 Sl Break points sessies rira eearri er ee A EEEE a EE E REESE EATE EE REEERE 51 5 1 1 Setting breakpoints rasini Geen E E mA E 52 5 1 2 Setting Catchpoints isea eoi seule ata cae ee eee eat 56 5 1 9 Deleting break points restos seii ea a inertia A E EEA 58 5 1 4 Disabling Preak Pout ssisiciccct haa eti ei aree enie aa etia e eaaa e a aa Ea 58 5 1
183. cs to view and edit the source files for the program you are debugging with GDB To use this interface use the command M x gdb in Emacs Give the executable file you want to debug as an argument This command starts GDB as a subprocess of Emacs with input and output through a newly created Emacs buffer Using GDB under Emacs is just like using GDB normally except for two things All terminal input and output goes through the Emacs buffer This applies both to GDB commands and their output and to the input and output done by the program you are debugging This is useful because it means that you can copy the text of previous commands and input them again you can even use parts of the output in this way All the facilities of Emacs Shell mode are available for interacting with your program In particular you can send signals the usual way for example C c C c for an interrupt C c C z for a stop GDB displays source code through Emacs Each time GDB displays a stack frame Emacs automatically finds the source file for that frame and puts an arrow gt at the left margin of the current line Emacs uses a separate buffer for source display and splits the screen to show both your GDB session and the source Explicit GDB list or search commands still produce output as usual but you probably have no reason to use them from Emacs Warning If the directory where your program resides is not your current di rectory it can
184. ct numchild n children name name numchild n type type repeats N times The var info type command Synopsis var info type name Returns the type of the specified variable name The type is returned as a string in the same format as it is output by the GDB CLI type typename The var info expression command Synopsis var info expression name Returns what is represented by the variable object name lang lang spec exp expression where lang specis C C Java The var show attributes command Synopsis var show attributes name List attributes of the specified variable object name status attr attr where attris editable noneditable TBD The var evaluate expression command Synopsis var evaluate expression name Evaluates the expression that is represented by the specified variable object and returns its value as a string in the current format specified for the object 358 The GDB MI Interface value value The var assign command Synopsis var assign name expression Assigns the value of expression to the variable object specified by name The object must be editable The var update command Synopsis var update name Update the value of the variable object name by evaluating its expression after fetching all the new values from memory or registers A causes all existing variable objects to be updated 21 14 GDB MI variable objects 359 360
185. ction tables The default is off The vtb1 commands do not work on programs compiled with the HP ANSI C compiler aCC Do not pretty print C virtual function tables Show whether C virtual function tables are pretty printed or not Values printed by the print command are saved in the GDB value history This allows you to refer to them in other expressions Values are kept until the symbol table is 8 8 Value history 95 re read or discarded for example with the file or symbol file commands When the symbol table changes the value history is discarded since the values may contain pointers back to the types defined in the symbol table The values printed are given history numbers by which you can refer to them These are a range of integers starting with one print shows you the history number assigned to a value by printing num before the value here num is the history number To refer to any previous value use followed by the history number of the value The way print labels its output is designed to remind you of this Just refers to the most recent value in the history and refers to the value before that n refers to the nth value from the end 2 is the value just prior to 1 is equivalent to and 0 is equivalent to For example suppose you have just printed a pointer to a structure and want to see the contents of the structure It suffices to type p S If you have a chain of structures
186. ction with a BREAK instruction The debugger cannot set a breakpoint in a shared library because doing so can affect other processes on the system in addition to the process being debugged 14 22 Debugging support for shared libraries 211 To set the breakpoint you must kill the program and then rerun it so that the dynamic linker maps a copy of the shared library privately There are two ways to run the program e Rerun the program under GDB to have the debugger cause dld to map all shared libraries as private enabling breakpoint debugging e On PA RISC systems use the following command on an executable opt langtools bin pxdb s on executable name The pxdb s on command marks the executable so that d1d maps shared libraries as private when the program starts up You can verify the status of the shared library with this command opt langtools bin pxdb s status executable name e Onboth PA RISC and IA64 systems use the following command on an executable chatr dbg enable executable name This is similar to the pxdb command described above wherein it directs the dld to load the shared libraries as private when the program starts up On HP UX 11i v3 Integrity systems WDB enables automatic debugging of shared libraries without them being mapped private while attaching to a running program For enabling automatic debugging of shared libraries you must install the kernel patches PHKL_38651 and PHKL_38778 14 22 5 Selectively Mapping
187. current status of JVM internal states Prints the current or specified Java frame locals information Prints details of static mutexes Prints the given Java object field information Locates Java object oop of the given Java heap address Locates references to the given Java object in the Java heap Prints unwind information of the code where the PC is located Prints the dynamically generated Java Unwind Table Typehelp java followed by the subcommand name for full documentation Command name abbreviations are allowed if they are unambiguous 14 25 Language support 219 14 25 1 3 Java corefile debugging support HP WDB shows stack traces of mixed Java C and C programs for java corefile GDB _JAVA_UNWINDLIB environment variable must be set to the path name of the Java unwind library as explained above Following are examples that illustrate the gdb command line options for invoking gdb on a core file 1 Invoke gdb on a core file generated when running a 32 bit Java application on an Integrity system with opt javal 4 bin java gdb opt javal 4 bin IA64N java core java 2 Invoke gdb ona core file generated when running a 64 bit Java application on an Integrity system with opt javal 4 bin java d64 gdb opt javal 4 bin IA64W java core java 3 Invoke gdb on a core file generated when running a 32 bit Java application on PA RISC using opt javal 4 bin java gdb opt javal 4 bin PA_RISC2 0 java core java 4 Invoke gdb on
188. d Even when they do the directories can be moved between the compilation and your debugging session GDB has a list of directories to search for source files this is called the source path Each time GDB looks for a source file it tries all the directories in the list in the order they are present in the list until it finds a file with the desired name Note that the executable search path is not used for this purpose Neither is the current working directory unless it happens to be in the source path If GDB cannot find a source file in the source path and the object program records a directory GDB tries that directory too If the source path is empty and there is no record of the compilation directory GDB looks in the current directory as a last resort Whenever you reset or rearrange the source path GDB clears out any information it has cached about where the source files are located and where each line is in the respective file When you start GDB its source path includes only cdir and cwd in that order To add other directories you can use the directory command directory dirname Add directory dirname to the front of the source dir dirname path Several directory names may be given to this command separated by on MS DOS and MS Windows where usually appears as part of absolute file names or a whitespace You can specify a directory that is already in the source path this moves it forward so GDB sea
189. d aeteuased bras ii nen iit as 115 Te ANS rity ERS CU igs dice esas deo cl hap peeccron a evs oes aden east daca whale uk caress AA Smad alee teane eee 119 11 1 Assignment to variables wes cesses ceess pana sisirin sisean aia E E Eaa kerinan 119 11 2 Continuing at a different Address ise iesce2ssnevccwvsa ss scensetodcestevdsdabenstecersdvevonnsncndens eves 120 11 3 Giving your program a SICA see us aiicka soe So teas vad use set eua oaks ou tuk ux cile Case va an vee eas 121 11 4 Returning from a fUMCHOM Lo cdescosasa tiny cceddsivaastec save ii en i E i R Ea eini 121 11 5 Calling programi LUI CH Ons erroris riisi iii riiseni ENN EREE saya N EES SEEEN aaas 122 11 6 Patching program S s eerie initiis e ia a i aii Eea 122 EAEI N al E EEA EE AT AA EANA EAE EAAS A PC 125 12 Commands to specify files negrore assist On E R E EAE SEAT ER 125 12 2 Specifying shared library lOCaAnOnS icone iain tei ent hane lait ese 130 173 Errors reading symbol Tiles ai ciecsvwievelaienccieds awseeassavteuvareeaiis vs Weeteustleeuse Orteaye cea 131 Table of Contents 5 13 Specifying a Debugging Target uss 3 aeviatetacnaicaceaeade sec sad ae daa Rabi eed ea ees 133 TOA BACHE TALE CES srei ene eos eaei e EA avons ea NE Suge UE A E EEES EA EEEE 133 13 2 Commands for managing targets sesessessserssiseesserssisseseissienrereessiesresrersreseesres 133 13 3 Choosing target pyte Orders irienn enirere eriein To eNA EEEE EAEE E TE ierni 135 14 HP UX Configuration Spec
190. d have output for it GDB could not parse a type specification output by the compiler 13 Specitying a Debugging Target A target is the execution environment occupied by your program Often GDB runs in the same host environment as your program in that case the debugging target is specified as a side effect when you use the file or core commands For HP UX specific information see undefined HP UX Targets page undefined When you need more flexibility for example running GDB on a physically separate host or controlling a standalone system over a serial port or a realtime system over a TCP IP connection you can use the target command to specify one of the target types configured for GDB see Commands for managing targets page 133 13 1 Active targets There are three classes of targets processes core files and executable files GDB can work concurrently on up to three active targets one in each class This allows you for example to start a process and inspect its activity without abandoning your work on a core file For example if you execute gdb a out then the executable file a out is the only active target If you designate a core file as well presumably from a prior run that crashed and coredumped then GDB has two active targets and uses them in tandem looking first in the corefile target then in the executable file to satisfy requests for memory addresses Typically these two classes of target are comp
191. db handle number stop handle number nostop z number i z number i with xdb handle number nopass handle number pass z number r z number r with xdb handle number print handle number noprint z number Q 16 8 10 Symbols Table 16 30 Symbols z number Q with xdb handle number noprint XDB Command Equivalent WDB Command line line file line file line proc proc file proc proc line No equivalent file proc proc label No equivalent class proc class proc class proc line No equivalent class proc labe1 No equivalent proc line name shared library No equivalent No equivalent var var class var class var bug not yet class proc class var proc var static variables only class proc depth class var No equivalent 16 8 Alphabetical lists of XDB commands and HP WDB equivalents 277 Table 16 30 Symbols continued XDB Command Equivalent WDB Command Return Return any string p any string dot Empty string for example p is the equivalent of p Return r x with xdb tui data with tui number number with tui note that a space is required between or and the number string string with xdb search regexp forw regexp string stri
192. development environments You do not have to use the she11 command for this purpose in GDB make make args Execute the make program with the specified arguments This is equivalent to shell make make args 2 3 Shell commands 31 32 3 GDB Commands You can abbreviate a GDB command to the first few letters of the command name if that abbreviation is unambiguous and you can repeat certain GDB commands by typing just RET You can also use the TAB key to get GDB to fill out the rest of a word in a command or to show you the alternatives available if there is more than one possibility 3 1 Command syntax e AGDB command is a single line of input There is no limit on how long it can be e It starts with a command name and is followed by arguments whose meaning depends on the command name e GDB command names can be truncated if that abbreviation is unambiguous The possible command abbreviations are listed in the documentation for individual commands In some cases even ambiguous abbreviations are allowed for example s is specially defined as equivalent to step even though there are other commands whose names start with s You can test abbreviations by using them as arguments to the help command e A blank line as input to GDB typing just RET means to repeat the previous command Some commands for example run do not repeat this way These are commands whose unintentional repetition might cause trouble and which you are unli
193. dr What body bkpt number 1 type breakpoint disp keep enabled y addr 0x000100d0 func main file hello c line 5 times 0 ignore 3 gdb The break condition command Synopsis break condition number expr Breakpoint number will stop the program only if the condition in expr is true The condition becomes part of the break 1ist output see the description of the break 1list command below GDB command The corresponding GDB command is condition Example gdb break condition 1 1 done gdb break list done BreakpointTable nr_ rows 1 nr_cols 6 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col_name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alignment 1 col_name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colhdr What body bkpt number 1 type breakpoint disp keep enabled y 21 5 GDB MI breakpoint table commands 313 addr 0x000100d0 func main file hello c line 5 cond 1 times 0 ignore 3 gdb The break delete command Synopsis break delete breakpoint Delete the breakpoint s whose number s are specified in the argument list This is obviously reflected in the breakpoint list GDB command The corresponding GDB command is delete
194. ds each word being word size bytes In total nr rows nr cols word size bytes are read returned as total bytes Should less than the requested number of bytes be returned by the target the missing words are identified using N A The number of bytes read from the target is returned in nr bytes and the starting address used to read memory in addr The address of the next previous row or page is available in next row and prev row next page and prev page GDB command The corresponding GDB command is x gdbtk has gdb_get_mem memory read command Example Read six bytes of memory starting at bytes 6 but then offset by 6 bytes Format as three rows of two columns One byte per word Display each word in hex gdb 9 data read memory o 6 bytes 6 x 1 3 2 9 done addr 0x00001390 nr bytes 6 total bytes 6 next row 0x00001396 prev row 0x0000138e next page 0x00001396 prev page 0x0000138a memory addr 0x00001390 data 0x00 0x01 addr 0x00001392 data 0x02 0x03 addr 0x00001394 data 0x04 0x05 gdb Read two bytes of memory starting at address shorts 64 and display as a single word formatted in decimal gdb 5 data read memory shorts 64 d 211 5 done addr 0x00001510 nr bytes 2 total bytes 2 326 The GDB MI Interface next row 0x00001512 prev row 0x0000150e next page 0x00001512 prev page 0x0000150e memory
195. e The type of target for instance async remote and so on parameters Device names host names and the like See Commands for managing targets page 133 for more details The output is a connection notification followed by the address at which the target program is in the following form connected addr address func function name args arg list GDB command The corresponding GDB command is target Example gdb target select async dev ttya connected addr 0xfe00a300 func args gdb 21 12 GDB MI thread commands The thread info command Synopsis thread info GDB command No equivalent Example N A The thread list all threads command Synopsis thread list all threads 21 12 GDB MI thread commands 353 GDB command The equivalent GDB command is info threads Example N A The thread list ids command Synopsis thread list ids Produces a list of the currently known GDB thread ids At the end of the list it also prints the total number of such threads GDB command Partof info threads supplies the same information Example No threads present besides the main process gdb thread list ids done thread ids number of threads 0 gdb Several threads gdb thread list ids done thread ids thread id 3 thread id 2 thread id 1 number of threads 3 gdb The thread select command Synopsis
196. e main offset 4 inst mov 2 00 address 0x000107c4 func name main offset 8 inst sethi hi 0x11800 02 gdb The data evaluate expression command Synopsis data evaluate expression expr Evaluate expr as an expression The expression could contain an inferior function call The function call will execute synchronously If the expression contains spaces it must be enclosed in double quotes GDB command The corresponding GDB commands are print output and ca11 In gdbtk only there is a corresponding gdb_eval command Example In the following example the numbers that precede the commands are the tokens described in GDB MI Command Syntax page 307 Notice how GDB MI returns the same tokens in its output 211 data evaluate expression A 211 done value 1 gdb 311 data evaluate expression amp A 311 done value 0xefffeb7ca gdb 411 data evaluate expression A 3 11 done value 4 gdb 511 data evaluate expression A 3 511 done value 4 gdb WN 322 The GDB MI Interface The data list changed registers Command Synopsis data list changed registers Display a list of the registers that have changed GDB command GDB does not have a direct analog for this command gdbtk has the corresponding command gdb changed register list Example On a PPC MBX board gdb exec continue running gdb stopped reason breakpoint hit bkptno 1
197. e a catchpoint like any other breakpoint To stop when your program receives a signal use the handle command see Signals page 67 GDB assigns a number to each breakpoint watchpoint or catchpoint when you create it these numbers are successive integers starting with one In many of the commands for controlling various features of breakpoints you use the breakpoint number to say which breakpoint you want to change Each breakpoint may be enabled or disabled if disabled it has no effect on your program until you enable it again Some GDB commands accept a range of breakpoints on which to operate A breakpoint range is either a single breakpoint number like 5 or two such numbers in increasing order separated by a hyphen like 5 7 When a breakpoint range is given to a command all breakpoint in that range are operated on 5 1 Breakpoints 51 5 1 1 Setting breakpoints Breakpoints are set with the break command abbreviated b The debugger convenience variable bpnum records the number of the breakpoint you have set most recently see Convenience variables page 96 for a discussion of what you can do with convenience variables You have several ways to say where the breakpoint should go break function break offset break offset break linenum break filename linenum break filename function break address break 52 Stopping and Continuing Set a breakpoint at entry to function function W
198. e code where the given pc is located java unwind table Print out the dynamically generated Java Unwind Table Type help java followed by java subcommand name for full documentation Command name abbreviations are allowed if unambiguous 218 HP UX Configuration Specific Information Java VM Debugging Commands The following commands have been added to enhance Java debugging support brbacktrace Prints backtrace of mixed Java and native frames Standard backtrace command of GDB has been enhanced to work with mixed Java and native stack frames info frame Prints Java frame specific information for a Java frame Standard frame command of GDB has been enhanced to interpret a Java stack frame info threads thread Java subcommands Prints state information for Java threads Prints detailed state information for the current Java thread The following Java subcommands have been added java args lt frame number gt java bytecodes lt met hodOop gt java heap histogram java instances lt klassOop gt java jvm state java locals java mutex info java object lt object ptr gt java oop lt Java_heap_address gt java references lt oop gt java unwind info lt pc gt java unwind table Prints the current or specified Java frame arguments information Disassembles the given Java method bytecode Displays the Java heap object histogram Locates the instances of the given klassOop in the Java heap Prints
199. e end 300 GDB Annotations where source intro string separates for the user s benefit the reference from the text which precedes it filename is the name of the source file and line number is the line number within that file the first line is line 1 If GDB prints some information about where the frame is from which library which load segment etc currently only done on the RS 6000 it is annotated with Z Zframe where information Then if source is to be actually displayed for this frame for example this is not true for output from the backtrace command then a source annotation see Displaying source page 304 is displayed Unlike most annotations this is output instead of the normal text which would be output not in addition 20 5 Displays When GDB is told to display something using the display command the results of the display are annotated Z Zdisplay begin number Z Zdisplay number end number separator Z Zdisplay format format Z Zdisplay expression expression Z Zdisplay expression end expression separator Z Zdisplay value value Z Zdisplay end where number is the number of the display number separator is intended to separate the number from what follows for the user format includes information such as the size format or other information about how the value is being displayed expressionis the expression being displayed expression separatoris intended
200. e file has the following format S sArrayBrowsing matrix array ARRAY A 5x5 matrix 5 NODANOU 224 HP UX Configuration Specific Information where ARRAY is the name of the array and its size is 5x5 The first two lines are comments about this file and the array The third line denotes the array coordinates From the fourth line the elements of the array are listed Note This feature is not supported for the Fortran array slices 14 27 2 Support for Fortran array slices HP WDB prints Fortran array slices if you specify a range of elements by the Fortran 90 array section syntax For instance for an array X declared by REAL DIMENSION 1 1 2 10 X youcould print all five even numbered elements of the row with the first dimension equal to 0 by typing the WDB command print X 0 2 10 2 14 27 3 Displaying enumerators You can display the union of several enumeration elements by specifying a value if the elements of the enumeration type are the powers of 2 and the given value is a sum of any given combination of the enumeration elements For example assume you have an enumerated type named color in the program with these elements RED 0 ORANGE 1 YELLOW 2 GREEN 8 and BLUE 16 Ifyou use the command printf 3 the debugger displays ORANGE YELLOW the elements corresponding to 1 and 2 If you print 5 you will get the value 5 because it does not form the sum of any combination in the set However if you wanted to print 25 y
201. e file was written in C and GDB was parsing Modula 2 a command such as print a b c might not have the effect you intended In C this means to add b and c and place the result in a The result printed would be the value of a In Modula 2 this means to compare a to the result of b c yielding a BOOLEAN value 9 1 3 Having GDB infer the source language To have GDB set the working language automatically use set language local or set language auto GDB then infers the working language That is when your program stops in a frame usually by encountering a breakpoint GDB sets the working language to the language recorded for the function in that frame If the language for a frame is unknown that is if the function or block corresponding to the frame was defined in a source file that does not have a recognized extension the current working language is not changed and GDB issues a warning This may not seem necessary for most programs which are written entirely in one source language However program modules and libraries written in one source language can be used by a main program written in a different source language Using set language auto in this case frees you from having to set the working language manually 102 Using GDB with Different Languages 9 2 Displaying the language The following commands help you find out which language is the working language and also what language source files were written in show
202. e integer in hexadecimal d Print as integer in signed decimal u Print as integer in unsigned decimal O Print as integer in octal Examining Data t Print as integer in binary The letter t stands for two a Print as an address both absolute in hexadecimal and as an offset from the nearest preceding symbol You can use this format used to discover where in what function an unknown address is located gdb p a 0x54320 3 0x54320 lt _initialize vx 396 gt Regard as an integer and print it as a character constant Regard the bits of the value as a floating point number and print using typical floating point syntax For example to print the program counter in hex see Registers page 98 type p x pc Note that no space is required before the slash this is because command names in GDB cannot contain a slash To reprint the last value in the value history with a different format you can use the print command with just a format and no expression For example p x reprints the last value in hex 8 5 Examining memory You can use the command x for examine to examine memory in any of several formats independent of your program data types x nfu addr Use the x command to examine memory x addr x n and u are all optional parameters that specify how much memory to display and how to format it addris an expression giving the address where you want to start displaying memory
203. e level This option sets the annotation level inside GDB Its effect is identical to using set annotate level see GDB Annotations page 297 Annotation level controls how much information does GDB print together with its prompt values of expressions source lines and other types of output Level 0 is the normal level 1 is for use when GDB is run as a subprocess of GNU Emacs level 2 is the maximum annotation suitable for programs that control GDB async Use the asynchronous event loop for the command line interface GDB processes all events such as user keyboard input via a special event loop This allows GDB to accept and process user commands in parallel with the debugged process being run so you do not need to wait for control to return to GDB before you type the next command A NOTE As of version 5 0 the target side of the asynchronous operation is not yet in place so async does not work fully yet When the standard input is connected to a terminal device GDB uses the asynchronous event loop by default unless disabled by the noasync option noasync Disable the asynchronous event loop for the command line interface baud bps b bps Set the line speed baud rate or bits per second of any serial interface used by GDB for remote debugging tty device t device Run using device for your program s standard input and output tui Use a Terminal User Interface For information use your Web b
204. e line and code address class proc class proc Source line and code address class proc line No equivalent Source line and code address class proc label No equivalent Source line and code address proc line No equivalent Code address class proc line No equivalent Code address label No equivalent Source line and code address name shared library No equivalent Address of name in shared library shared library 16 5 XDB special language operators and HP WDB equivalents The following table lists the XDB and the equivalent WDB commands for language operators 268 XDB to WDB Transition Guide Table 16 18 Special language operators XDB Language Operator WDB Equivalent Meaning addr Depends on language Unary operator address of object in No equivalent Unary Boolean operator execution in procedure sizeof sizeof Unary operator size of object 16 6 XDB special variables and HP WDB equivalents GDB does not provide special variables of the kind that XDB has but you can use show and set to display and modify many debugger settings Table 16 19 Special variables XDB Special Variable WDB Equivalent Meaning cplusplus No equivalent C feature control flags depth No equivalent Default stack depth for local variables fpa No equivalent Treat FPA sequence as one instruction fpa_reg No equivalent Address register for FPA sequences Slang show l
205. e native language of your program and allowing GDB to output values in a manner consistent with the syntax of the native language The language you use to build expressions is called the working language 9 1 Switching between source languages There are two ways to control the working language You can have GDB set it automatically or you can select it manually You can use the set language command for either purpose On startup GDB sets the default language automatically The working language is used to determine how expressions are interpreted how values are printed and so on In addition to the working language every source file that GDB knows about has its own working language For some object file formats the compiler might indicate which language a particular source file is in However most of the time GDB infers the language from the name of the file The language of a source file controls whether C names are demangled this way backtrace can show each frame appropriately for its own language There is no way to set the language of a source file from within GDB but you can set the language associated with a filename extension See Displaying the language page 103 This is a common problem when you use a program such as cfront or f2c that generates C but is written in another language In that case make the program use line directives in its C output that way GDB will know the correct language of the source code of the
206. e not yet implemented Motivation The motivation for this collection of commands Introduction A brief introduction to this collection of commands as a whole Commands For each command in the block the following is described Synopsis command args GDB command The corresponding GDB CLI command Result Out of band Notes Example 21 5 GDB MI breakpoint table commands This section documents GDB MI commands for manipulating breakpoints The break after Command Synopsis break after number count The breakpoint number number is not in effect until it has been hit count times To see how this is reflected in the output of the break 1ist command see the description of the break 1ist command below GDB command The corresponding GDB command is ignore 312 The GDB MI Interface Example gdb break insert main done bkpt number 1 type breakpoint disp keep enabled y addr 0x000100d0 func main file hello c line 5 times 0 gdb break after 1 3 done gdb break list done BreakpointTable nr_ rows 1 nr_ cols 6 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col_name type colhdr Type width 4 alignment 1 col_name disp colhdr Disp width 3 alignment 1 col_name enabled colhdr Enb width 10 alignment 1 col_name addr colhdr Address width 40 alignment 2 col_name what colh
207. e radix unchanged no matter what it was set output radix base Set the default base for numeric display Supported choices for base are decimal 8 10 or 16 base must itself be specified either unambiguously or using the current default radix show input radix Display the current default base for numeric input show output radix Display the current default base for numeric display 17 6 Optional warnings and messages By default GDB is silent about its inner workings If you are running on a slow machine you may want to use the set verbose command This makes GDB tell you when it does a lengthy internal operation so you will not think it has crashed Currently the messages controlled by set verbose are those which announce that the symbol table for a source file is being read see symbol file in Commands to specify files page 125 set verbose on Enables GDB output of certain informational messages set verbose off Disables GDB output of certain informational messages show verbose Displays whether set verbose is on or o By default if GDB encounters bugs in the symbol table of an object file it is silent but if you are debugging a compiler you may nd this information useful see Specifying shared library locations page 130 set complaints limit Permits GDB to output 1imit complaints about each type of unusual symbols before becoming silent about the problem Set limit to zero to suppress all complaints set it
208. e s arguments e the address of the frame s local variables e the program counter saved in it the address of execution in the caller frame e which registers were saved in the frame The verbose description is useful when something has gone wrong that has made the stack format fail to fit the usual conventions Print a verbose description of the frame at address addr without selecting that frame The selected frame remains unchanged by this command This requires the same kind of address more than one for some architectures that you specify in the frame command See Selecting a frame page 73 Print the arguments of the selected frame each on a separate line Print the local variables of the selected frame each on a separate line These are all variables declared either static or automatic accessible at the point of execution of the selected frame Print a list of all the exception handlers that are active in the current stack frame at the current point of execution To see other exception handlers visit the associated frame using the up down or frame commands then type info catch See Setting catchpoints page 56 6 6 Information aboutaframe 75 76 7 Examining Source Files GDB can print parts of the source code of your program since the debugging information recorded in the program tells GDB what source files were used to build it When your program stops GDB spontaneously prints the line where i
209. e unpacked The second argument is given if the core file is too large to fit in the packcore file It is the path to 200 HP UX Configuration Specific Information the core file to be used if the packcore directory does not contain a core file If used this second argument causes a symbolic link to be created in the packcore directory in place of the missing core file The getcore command can be used to examine a packcore directory which was previously created by unpackcore It takes one optional argument the name of the packcore directory which defaults to packcore 14 15 2 Support for the info target Command The info target command is enhanced to display the memory segments for the corefile The output also displays other details such as system name node name operating system release name license level and machine model for the core file The enhancement is available for HP UX 11i v2 and later versions of Itanium systems Following is the sample output for the enhanced info target command gdb file info_target Reading symbols from info_target done gdb core core Core was generated by info_target Program terminated with signal 6 Aborted 0 0xc00000000032c5b0 0 in kill 0x30 from usr lib hpux64 libc so 1 gdb info target Operating System Information sysname HP UX nodename testl release B 11 23 version U 128 user 256 user or Unlimited user system machine ia64 idnumber 0735747273 Symbo
210. eatures Invoke WDB with the command gdb tui to obtain a terminal user interface TUI similar to that provided by XDB Commands marked with tui are valid when you use the tui option Invoke WDB with the command gdb xdb to turn on XDB compatibility mode which enables you to use many XDB commands as synonyms for GDB commands Commands marked with xdb are valid when you use the xdb option You may use both xdb and tui at the same time Some commands are valid only when you use both options For a tutorial introduction to WDB refer to the Getting Started with WDB e By function lists of XDB commands and HP WDB equivalents page 253 e Overall breakpoint commands page 260 e XDB data formats and HP WDB equivalents page 266 e XDB location syntax and HP WDB equivalents page 268 e XDB special language operators and HP WDB equivalents page 268 e XDB special variables and HP WDB equivalents page 269 e XDB variable identifiers and HP WDB equivalents page 270 e Alphabetical lists of XDB commands and HP WDB equivalents page 270 16 1 By function lists of XDB commands and HP WDB equivalents e Invocation commands e Window mode commands e File viewing commands e Source directory mapping commands e Data Viewing and modification commands e Stack viewing commands e Status viewing command e Job control commands e Au
211. ebugger To use Batch RTC after attaching GDB to a running process complete the following steps 14 10 Debugging Memory Problems 171 1 Complete one of the following steps to preload the librtc runtime library Set the target application to preload 1ibrtc by using the rtc option for the chatr command In addition to automatically loading the librtc library the rtc option for the chat r command also maps the shared libraries as private To enable or disable the target application to preload the librtc runtime library enter the following command at the HP UX prompt chatr rtc lt enable disable gt lt executable gt A NOTE To attach and nd leaks for PA 32 applications from the startup the 5 environment variable RTC_INIT should be set to on in addition to preloading the librtc s1 so library before starting the application as follows RTC_INIT on lt executable gt OR Instead of automatically preloading 1ibrtc and mapping the shared libraries you can explicitly preload the required librtc library In the case of HP 9000 systems you must explicitly map the share libraries as private by using the dbg enable option for the chat r command as follows chatr dbg enable lt executable gt This step is not required on Integrity systems To explicitly preload the 1ibrtc runtime library and start the target application enter one of the following commands For 32 bit IPF applications LD_PRELOAD opt l
212. ebugging information organized into two lists files whose symbols have already been read and files whose symbols will be read when needed Print the names and data types of all defined functions info functions regexp info variables info variables regexp Print the names and data types of all defined functions whose names contain a match for regular expression regexp Thus info fun step finds all functions whose names include step info fun step finds those whose names start with step Print the names and data types of all variables that are declared outside of functions that is excluding local variables Print the names and data types of all variables except for local variables whose names contain a match for regular expression regexp Some systems allow individual object files that make up your program to be replaced without stopping and restarting your program For example in VxWorks you can simply recompile a defective object file and keep on running If you are running on one of these systems you can allow GDB to reload the symbols for automatically relinked modules set Replace symbol definitions symbol reloading for the corresponding source on file when an object file with a particular name is seen again set Do not replace symbol symbol reloading definitions when off encountering object files of the same name more than once This is the default state if you are not running on a system
213. ecause any time you resume execution even with a simple next or step you may encounter another breakpoint which could have its own command list leading to ambiguities about which list to execute If the first command you specify ina command list is silent the usual message about stopping at a breakpoint is not printed This may be desirable for breakpoints that are to print a specific message and then continue If none of the remaining commands print anything you see no sign that the breakpoint was reached silent is meaningful only at the beginning of a breakpoint command list The commands echo output and printf allow you to print precisely controlled output and are often useful in silent breakpoints See Commands for controlled output page 290 For example here is how you could use breakpoint commands to print the value of x at entry to foo whenever x is positive break foo if x gt 0 commands silent printf x is d n x cont end One application for breakpoint commands is to compensate for one bug so you can test for another Put a breakpoint just after the erroneous line of code give it a condition to detect the case in which something erroneous has been done and give it commands to assign correct values to any variables that need them End with the cont inue command so that your program does not stop and start with the silent command so that no output is produced Here is an example break 403 commands sil
214. ecial character for example n for newline String constants are a sequence of character constants surrounded by double quotes Any valid character constant as described above may appear Double quotes within the string must be preceded by a backslash so for instance a b c is a string of five characters Pointer constants are an integral value You can also write pointers to constants using the C operator amp Array constants are comma separated lists surrounded by braces and for example 1 2 3 is a three element array of integers 1 2 3 4 5 6 is a three by two array and amp hi amp there amp fred isa three element array of pointers 108 Using GDB with Different Languages 9 4 1 3 C expressions A GDB expression handling can interpret most C expressions WARNING GDB can only debug C code if you use the proper compiler Typically C debugging depends on the use of additional debugging information in the symbol table and thus requires special support In particular if your compiler generates a out MIPS ECOFF RS 6000 XCOFF or ELF with stabs extensions to the symbol table these facilities are all available With GNU CC you can use the gstabs option to request stabs debugging extensions explicitly Where the object code format is standard COFF or DWARF in ELF on the other hand most of the C support in GDB does not work 1 Member function calls are a
215. ed sub options for the pathtrace compiler option You must set the following pathtrace compiler option to enable the debugger to print the execution path entries pathtrace lt global global_fixed_size gt lt locals gt 204 HP UX Configuration Specific Information For more information on this feature see the following example 14 16 2 Example Illustrating Execution Path Recovery The following example illustrates the use of the execution path recovery feature in HP WDB Sample Program Scat execpath c include lt stdio h gt include lt string h gt include lt stdlib h gt int main int a 3y Dos Op C 43 if a printf Value of a greater than 0 n if b printf Value of b greater than 0 n if c printf Value of c greater than 0 n printf All condition checking done n return 0 Sample Debugging Session cc pathtrace g execpath c Sgdb a out HP gdb Type show warranty for warranty support gdb b main Breakpoint 1 at 0x4000a60 0 file execpath c line 7 from a out gdb r Starting program a out Breakpoint 1 main at execpath c 7 7 ant a S73 bs 05 c 4s gdb n 9 if a gdb i ep Local execution path table for main empty gdb i gep Global execution path table empty gdb n 10 printf Value of a greater than 0 n gdb n Value of a greater than 0 12 if b 14 16 Printing the Execution Path Entries for the Current Frame or
216. ee Debugging Memory in Interactive Mode page 159 See Debugging Memory in Batch Mode page 164 See Debugging Memory Interactively After Attaching to a Running Process page 171 14 10 4 Debugging Memory in Interactive Mode This section describes the various commands which help in debugging memory problems when the debugger is used in the interactive mode 14 10 4 1 Commands for interactive memory debugging To debug memory problems use these commands set heap check on off This toggles the capability for detection of leaks heap profiles bounds checking and checking for double free info heap Displays a heap report listing information such as the start of heap end of heap heap size heap allocations size of blocks and number of instances The report shows heap usage at the point you use the info heap command The report does not show allocations that have already been freed For example if you make several allocations free them all and then you 14 10 Debugging Memory Problems 159 info heap filename info heap idnumber show heap check set heap check interval lt nn gt set heap check repeat lt nn gt set heap check reset info heap interval lt file name gt set heap check leaks on off info leaks 160 HP UX Configuration Specific Information use info heap the result does not show any allocations Writes heap report output to the specified file Produces
217. em or make them conditional Each time you use the rop command HP WDB adds an additional breakpoint at the beginning of each function that performs the commands you specify if any e rdp Deletes all the breakpoints set by the rbp command This example shows how to set a breakpoint at the start of each procedure that displays information at the breakpoint gdb file a out Reading symbols from a out done gdb rbp Breakpoints set from 170 to 211 Type commands to execute when the breakpoint is hit one command per line End with a line saying just end gt info break gt end gdb 14 21 5 Support for template breakpoints With HP WDB 5 0 you can set breakpoints on all instantiations of the template class by just specifying the template name with member function name For example gdb break It is not necessary to specify the instantiation type 14 21 Enhanced support for watchpoints and breakpoints 209 Setting a breakpoint on a template method with multiple instantiations displays a menu showing all instantiations and the user can choose to set breakpoints on all or any one or none For example gdb file test Reading symbols from test done gdb b MyClass MyMember 0 cancel 1 all 2 MyClass MyMember int int at test C 14 3 MyClass MyMember int float at test C 14 4 MyClass MyMember int double at test C 14 14 22 Debugging support for shared libraries On HP UX shared librari
218. empts to invoke the redefined version instead of using the original meaning 9 4 1 2 C and C constants GDB allows you to express the constants of C and C in the following ways Integer constants are a sequence of digits Octal constants are specified by a leading 0 that is zero and hexadecimal constants by a leading 0x or 0X Constants can also end with a letter l specifying that the constant should be treated as a long value Floating point constants are a sequence of digits followed by a decimal point followed by a sequence of digits and optionally followed by an exponent An exponent is of the form e nnn where nnn is a sequence of digits The is optional for positive exponents A floating point constant may also end with a letter f or F specifying that the constant should be treated as being of the float as opposed to the default double type or with a letter 1 or L which specifies a long double constant Enumerated constants consist of enumerated identifiers or their integral equivalents Character constants are a single character surrounded by single quotes or a number or the ordinal value of the corresponding character usually its ASCII value Within quotes the single character may be represented by a letter or by escape sequences which are of the form nnn where nnn is the octal representation of the character s ordinal value or of the form x where x is a predefined sp
219. end of text can be used as in C to continue the command onto subsequent lines For example echo This is some text n which is continued n onto several lines n produces the same output as echo This is some text n echo which is continued n echo onto several lines n output expression Print the value of expression and nothing but that value no newlines no nn The value is 4 On DOS Windows systems the home directory is the one pointed to by the HOME environment variable 290 Canned Sequences of Commands output fmt expression printf string expressions not entered in the value history either See Expressions page 83 Print the value of expression in format fmt You can use the same formats as for print See Output formats page 86 Print the values of the expressions under the control of string The expressions are separated by commas and may be either numbers or pointers Their values are printed as specified by string exactly as if your program were to execute the C subroutine printf string expressions For example you can print two values in hex like this printf foo bar foo Ox x Ox x n foo bar foo The only backslash escape sequences that you can use in the format string are the simple ones that consist of backslash followed by a letter 18 4 Commands for controlled output 291 292 19 Using GDB under gnu Emacs A special interface allows you to use gnu Ema
220. ent set X y 4 cont end 5 1 7 Breakpoint menus 62 Some programming languages notably C permit a single function name to be defined several times for application in different contexts This is called overloading When a function name is overloaded break function is not enough to tell GDB where you want a breakpoint If you realize this is a problem you can use something like break function types to specify which particular version of the function you want Otherwise GDB offers you a menu of numbered choices for different possible breakpoints and waits for your selection with the prompt gt The first two options are Stopping and Continuing always 0 cancel and 1 all Typing 1 sets a breakpoint at each definition of function and typing 0 aborts the break command without setting any new breakpoints For example the following session excerpt shows an attempt to set a breakpoint at the overloaded symbol String after We choose three particular definitions of that function name gdb all gt 24 6 0 al 2 file 3 file 4 file 5 file 6 file 7 file cancel Breakpoint 1 at Breakpoint 2 at Breakpoint 3 at Multiple breakpoints were set Use the delete breakpoints gdb String String String String String String b String after cc line cc line cc line cc line cc line cc line Oxb26c Oxb344 Oxafcc command to delete unwanted 5
221. eos eent eretan eier A E T EEE E 308 21 1 3 Simple examples of GDB MI interaction s sessesssessesseesseisrrseersersriseeeseessese 310 21 2 GDB MI compatibility with GLa sified wectdaasten isa oenar r EEEa KAE EV SEKERE E a i 310 21 3 GDB ANT OUD TECOL S24 icreehissticiccl sn aN EN E EE E EASE E E 311 21 3 1 GDB MI result records naia a N TA 311 21 3 2 GDB MI stream TeCOrd Secate EEE ER PTER CEEA ETE 311 21 3 3 GDB MI out of band records siers aeiia NENE EES NENE e as ta 311 21 4 GDB MI command description format ssssssseseseseississssserssissseseessessrereesseesreseense 311 21 5 GDB MI breakpoint table command s ssessssssessessserssissssserssissrssesseesreseesseeseeseense 312 21 6 CDB MI Data manipulation sineset nsrnasisiiisuian virit ria A EnA i iie 320 21 7 GDB MI progr mi Controle sscaniiiesnriion iiaae a i er ai E a eine 330 21 8 Miscellaneous GDB commands in GDB MI eessssessessesssreessereesserreserrreseerreseereeseerres 339 21 9 GDB MI Stack Manipulation CommandS s sssssessseisssessserssisssserssieneseesseeseesrense 341 21 10 GDB MI Symbol query commandsS sesessseiseisessseissessssserssissreseesseenresesseesresnense 346 21 11 GDB MI Target Manipulation CommandS s sesssesssssesssesssissrsseessessreseesseesreseense 349 21 12 GDB MI thread command Soa trauren aaa EAA eea ASEE EEEREN INEEN EEEa 353 21 13 GDB MI tracepoint COMIMAN AS ysis icaessetevsvneagecpaeios oteesene peer so uanieadpecna
222. epeasteaskersyectseansveeieogeens 263 16 2 6 Assertion Control COMMANAS cccccc cesses ccceeessccceeeesscceusesceseueessecsueessseeureseeeeuess 264 16 2 7 Record and play back commands ccciccessis chcisrcacets ive cuainetincsiinvecacsiemnddesntinens 264 16 2 8 Macto facility Commands acasa clon Acie seeceeeecuiciel dan tenamanemeleinedics 264 16 2 9 Signal control commands sssseseseessesesssssestesesstsresssseesessestesessesensrensesseseees 265 10 Table of Contents 16 2 10 Miscellaneous COMMANAS ccccescecssecccsccccsscecsecccusceesescecsecceesceauecceaseceneesess 265 16 3 XDB data formats and HP WDB equivalentsscci cst cssvconcinc sens doucscvcedioortassneveeenieerss 266 16 4 XDB location syntax and HP WDB equivalent ccccececeseesseceesceeeeeseeeseeeeesenes 268 16 5 XDB special language operators and HP WDB equivalents cccceccesseeeseeees 268 16 6 XDB special variables and HP WDB equivalent 0cccceccessecessceeeesseeeseeenseenes 269 16 7 XDB variable identifiers and HP WDB equivalents cccccescessceesseeseeeseeeeeeeees 270 16 8 Alphabetical lists of XDB commands and HP WDB equivalents ccccseee 270 I Std WE LE EA AT NA TSEN EEA EET MOR AS 270 NERA o EA E E AE EEEE E EE EA A TAS 271 16 8 3 C through Diciis eorr piersi rae e EE o EE AE EEADERS EESE EE EEEE NEETI SER 272 16 84 E through sgt crises grisienien inin en AES Ea ear EEE Ea 273 TOS T Uur eaaa a ara a A A
223. erence calls This support is available for PA 32 bit as well e Implementation of mapshared option to suppress mapping all the shared libraries in a process private e Support for deferred breakpoints on dlopened and shl_1loaded libraries with stripped main program e Additional support for procedural breakpoints e 99 variable arrays implemented on Integrity systems This support is available on PA RISC as well e The show envvars command can be used to print information on environment variables supported by WDB e Support for handling fpreg data type e Support for making changes to the program when debugging without having to re compile or re link it e Hardware breakpoints on Integrity systems e Support for debugging PA RISC Applications on Integrity systems e Unwinding Java stack frames on Integrity systems The 64 bit version of gdb can unwind through Java stack frames using the shared library in the Java product The 64 bit library is part of the JDK 1 4 2 10 and JDK 1 5 0 03 products e Enhanced nexti and stepi commands The WDB nexti and stepi commands prints the assembly instruction along with the next source line 138 HP UX Configuration Specific Information Enhanced info symbol ADDRESS command The info symbol ADDRESS command has been enhanced to search for a symbol at the given address Previously the info symbol command could be used only to search the global namespace Enhanced Java debugging support Support
224. erty source for the liberty free software library egdb gdb 199991101 opcodes source for the library of opcode tables and disassemblers gdb gdb 199991101 readline source for the gnu command line interface 5 gdb gdb 199991101 glob source for the gnu filename pattern matching subroutine 5 Ifyou have a more recent version of GDB than gdb 199991101 look at the README file in the sources we may have improved the installation procedures since publishing this manual 365 gdb gdb 199991101 mmalloc source for the gnu memory mapped malloc package The simplest way to configure and build GDB is to run configure from the gdb version number source directory which in this example is the gdb gdb 199991101 directory First switch to the gdb version number source directory if you are not already in it then run configure Pass the identifier for the platform on which GDB will run as an argument For example cd gdb gdb 199991101 configure host make where host is an identifier such as sun4 or decstation that identifies the platform where GDB will run You can often leave off host configure tries to guess the correct value by examining your system Running configure host and then running make builds the bfd readline mmalloc and libiberty libraries then gdb itself The configured source files and the binaries are left in the corresponding source directories configure is a Bourne shell bin sh script if your
225. es are special Until the library is loaded GDB does not know the names of symbols However GDB gives you two ways to set breakpoints in shared libraries e deferred breakpoints e catch load command 14 22 1 Using shared library as main program If the main program is in a shared library and you try to load it as follows gdb symbol file main sl Load new symbol table from main sl y or n y Reading symbols from main sl done Things don t appear to work This command is not the correct thing to do This command assumes that main s1 is loaded at its link time address This is not true for shared libraries Do not use symbol file with shared libraries Instead what you should do is to use the deferred breakpoint feature to set breakpoints on any functions necessary before the program starts running gdb b main Breakpoint 1 deferred at main main was not found Breakpoint deferred until a shared library containing main is loaded gdb r Once the program has started running it will hit the breakpoint In addition the de bugger will then already know about the sources for main since it gets this information when the shared library is loaded 210 HP UX Configuration Specific Information 14 22 2 Setting Deferred Breakpoints in Shared Library On HP UX GDB automatically loads symbol definitions from shared libraries when you use the run command or when you examine a core file Before you issue the run co
226. ess for x to examine also set _ to that address These commands include info line and info breakpoint The type of _ is void except when set by the x command in which case it is a pointer to the typeof _ The variable __ is automatically set by the x command to the value found in the last address examined Its type is chosen to match the format in which the data was printed _exitcode The variable exitcode is automatically set to the exit code when the program being debugged terminates On HP UX systems if you refer to a function or variable name that begins with a dollar sign GDB searches for a user or system name first before it searches for a convenience variable 8 9 Convenience variables 97 8 10 Registers 98 You can refer to machine register contents in expressions as variables with names starting with The names of registers are different for each machine Use info registers to view the names used on your machine info registers Print the names and values of all registers except floating point registers in the selected stack frame info all registers Print the names and values of all registers including floating point registers info registers regname Print the relativized value of each specified register regname As discussed in detail below register values are normally relative to the selected stack frame regname may be any register name valid on the machine you are using with or without
227. ess iva singes taviecosestvonslebenenaeens 201 14 15 3 Support for the Gump cere Command is ce ose ectias rads esac teaasihe 202 14 15 3 1 Enhancements to the dumpcore COMMANA scceceeeeeseesetteeeeeeeeeeees 202 14 15 4 Support for display of run time type information 0 cee esses cess eees 203 14 16 Printing the Execution Path Entries for the Current Frame or Thread 203 14 16 1 Compiler Dependencies for Printing the Execution Path Entries 204 14 16 2 Example Illustrating Execution Path Recovery ccccccsescessceessesssesseeesseees 205 14 17 Command to Unwind Beyond 10000 Frames cceececeesseeesecessceeeeesseeesseceeeenes 206 14 18 Invoking GDB Before a Program A DOrts c s cc sccscveileksneetesnsiviecachotyik covved edhtvecevansvins 207 14 19 Aborting a Command Line Call ccscisztisvncsnscpeske cess onve cunv tetaeeny need deynithed edavantesunvaabacens 207 14 20 Instruction Leyel Step pin Gs eiiis ninien aaa arinei a eiiis 208 14 21 Enhanced support for watchpoints and breakpoints sssssesesssessseisrssesrserseesees 208 14 21 1 Deferred watcApoiNtS a tietisssccassuveectdisedeciayevticbesseuivelone lt tath tives EErEE oneness 208 1421 2 Hardware Watch powitsis esiericacaiviiereoncraiiennesenisatiniaeeesranaunew an 208 142153 Hardware breakpoints estireto entere ainia i e R a Eaa 208 14 21 3 1 Setting breakpoints in unstripped shared library s sssssesssessseeseese
228. esse 209 14 21 4 Support for procedural breakpoints s sssssesssessesssssesssessrsreesserssesresserssesees 209 14 21 5 Support for template break poise sc seiivesscsatcvsiscets ctstonsvvesteessstivelcretndss 209 14 22 Debugging support for shared libraries cccecceeceeseeeecseceseceeeeeseeesseeeneeenes 210 14 22 1 Using shared library as main PrOSlaM oi svvssccservicentsertecenteuvaevonstasraasnveberden s 210 14 22 2 Setting Deferred Breakpoints in Shared Library ccccceeseesseeseesseeesseees 211 14 22 39 Usine Cate Oa Cy ces ister nei Eea eaea EEEE e EEEE ERARAS ESRAS EEEE REACER EER E 211 14 22 4 Privately mapping shared JIDraries i 0s csssveysus tccwsseseceny neon cepsiesed edeventosnnvendecens 211 14 22 5 Selectively Mapping Shared Libraries As Private cccecccesseesseesseeesseees 212 14 22 6 Setting breakpoints in shared LDLrary vias cecscsisesvcossncesscene ress seonnacesvay vtvvedeevnreden 213 14 22 7 Enhancement to the info shared CommMand wic ccccccccccccssccccsssescceeesesseeeeees 213 14 23 Debugging support for Decimal Floating Point data type cccceeseseeseereeneees 213 14 23 1 Printing Decimal Floating point data types ccec ccc cssceeeeeeseeeeeeneeeeseenes 213 14 23 1 1 Printing Decimal floating point constant 0 cec eee eens ceeeeeeeeeeees 214 14 23 1 2 Printing Decimal floating point Variable sciccoessssccsverisccerssnsecorvecrnens 214 14 232 Printing Na DIREC ISL
229. ession to the specified log file When you use the 10g command the debugger saves a snapshot of the current session from the start of the session to the point where you issued the log command Each time you use the log command HP WDB overwrites the specified log file with a new snapshot from the start of the session To run the Visual Interface for HP WDB use the following command Svdb tui To redirect HP WDB output to a log file named mylogfile use the log command in the following manner gdb log mylogfile The Visual Interface for HP WDB stores the log file mylogfile in the current directory To view the log file from Visual Interface for HP WDB start a shell process and use the following command gdb shell vi mylogfile 14 27 1 Support for dumping array in an ASCII file HP WDBN supports dumping an array into an ASCII file The array elements are stored in Array format of Matrix Market in a predefined column major order for Fortran arrays order The objective is to provide a simple mechanism to facilitate the exchange of matrix data and to enable easier parsing of the array elements For common file formats see http math nist gov MatrixMarket formats html To dump an array ARRAY to a file named DUMPFILE use the following command gdb dump2file ARRAY DUMPFILE The entries of ARRAY are dumped into an ASCII file named DUMPFILE in the array format The file is created in the current working directory The content of th
230. est to people debugging compilers If you are interested in seeing information about ill constructed symbol tables you can either ask GDB to print only one message about each such type of problem no matter how many times the problem occurs or you can ask GDB to print more messages to see how many times the problems occur with the set complaints command see Optional warnings and messages page 284 The messages currently printed and their meanings include inner block not inside outer block in The symbol information shows where symbol symbol scopes begin and end such as at the start of a function or a block of statements This error indicates that an inner scope block is not fully contained in its outer scope blocks GDB circumvents the problem by treating the inner block as if it had the same scope as the outer block In the error message symbol may be shown as don t know if the outer block is not a function block at address out of order The symbol information for symbol scope blocks should occur in order of in creasing addresses This error indicates that it does not do so GDB does not circumvent this problem and has trouble locating symbols in the source file whose symbols it is reading You can often determine what source file is affected by specifying set verbose on See Optional warnings and messages page 284 bad block start address patched The symbol information for a symbol scope block has a s
231. et GDB to print the source file and the line number when it prints a symbolic address set print symbol filename Tell GDB to print the source file name and line on number of a symbol in the symbolic form of an address set print symbol filename Do not print source file name and line number off of a symbol This is the default show print symbol filename Show whether or not GDB will print the source file name and line number of a symbol in the symbolic form of an address Another situation where it is helpful to show symbol filenames and line numbers is when disassembling code GDB shows you the line number and source file that corresponds to each instruction Also you may wish to see the symbolic form only if the address being printed is reasonably close to the closest earlier symbol set print max symbolic offset max offset show print max symbolic offset Tell GDB to only display the symbolic form of an address if the offset between the closest symbol and the address is less than max offset The default is 0 which tells GDB to always print the symbolic form of an address if any symbol precedes it Ask how large the maximum offset is that GDB prints in a symbolic address 8 7 Print settings 91 If you have a pointer and you are not sure where it points try set print symbol filename on Then you can determine the name and source file location of the variable where it points using p a pointer This interpr
232. ets the address in symbolic form For example here GDB shows that a variable ptt points at another variable t defined in hi2 c gdb set print symbol filename on gdb p a ptt 4 0xe008 lt t in hi2 c gt A WARNING For pointers that point to a local variable p a does not show the symbol name and filename of the referent even with the appropriate set print options turned on Other settings to control how different kinds of objects are printed set print array set print Pretty print arrays This format is more array on convenient to read but uses more space The default is off set print array off Return to compressed format for arrays show print array Show whether compressed or pretty format is selected for displaying arrays set print elements Set a limit on how many elements of an array number of elements GDB will print If GDB is printing a large array it stops printing after it has printed the number of elements set by the set print elements command This limit also applies to the display of strings When GDB starts this limit is set to 200 Setting number of elements to zero means that the printing is unlimited show print elements Display the number of elements of a large array that GDB will print If the number is 0 then the printing is unlimited set print null stop Cause GDB to stop printing the characters of an array when the first NULL is encountered This is useful when large arrays actual
233. event The user can step through once the nomem event is caught to see whether the out of memory event is handled correctly When set to on forces WDB to stop the program when it detects a call to free with an improper argument a call to realloc that does not point to a valid currently allocated heap block or a call to free a block of memory which has been corrupted Refer set heap check bounds for details on detecting memory corruption Toggles validation of calls to strcpy strncpy memcpy memccpy memset memmove bzero 14 10 Debugging Memory Problems 161 A set heap check bounds on off set heap check scramble on off info dangling info corruption set heap check min leak size num set heap check frame count num set heap check header size num of bytes 162 HP UX Configuration Specific Information and bcopy WDB 5 6 and later versions of the debugger also validates calls to streat and strncat NOTE HP WDB 6 0 and later versions of the debugger improves performance of memory debugging when the string option is set for 32 bit applications on HP UX 11i v2 and later on Itanium systems However the performance degrades for 64 bit applications on HP UX 11i v2 and later on Itanium systems Allocates extra space at the beginning and end of a heap block during allocation and fills it with a specific pattern When blocks are freed WDB verifies whether these patterns are intact If they are
234. ey may contain pointers to the internal data recording symbols and data types which are part of the old symbol table data being discarded inside GDB symbol file does not repeat if you press RET again after executing it once When GDB is configured for a particular environment it understands debugging information in whatever format is the standard generated for that environment you may use either a gnu compiler or other compilers that adhere to the local conventions For most kinds of object files the symbol file command does not normally read the symbol table in full right away Instead it scans the symbol table quickly to nd which source files and which symbols are present The details are read later one source file at a time as they are needed The purpose of this two stage reading strategy is to make GDB start up faster For the most part it is invisible except for occasional pauses while the symbol table details for a particular source file are being read The set verbose command can turn these pauses into messages if desired See Optional warnings and messages page 284 You can override the GDB two stage strategy for reading symbol tables by using the readnow filename readnow mapped core file filename option with any of the commands that load symbol table information if you want to be sure GDB has the entire symbol table available If memory mapped files are available on your syste
235. find size char max count start address length expri expr2 where size char Specifies the size of the pattern It can be b h w or g for 8 16 32 64 bit values respectively It is applicable only for hexadecimal patterns If size char is not specified the size is obtained from the type of the expression in the current programming language This is an optional parameter max count Specifies the maximum number of matching patterns to be displayed This is an optional parameter start address Specifies the start address in the given memory address range This parameter is mandatory end address Specifies the end address in the given memory address range This parameter is mandatory 196 HP UX Configuration Specific Information length Specifies the length of the memory address range This parameter is mandatory when end address is not specified exprl expr2 Specifies a variable or pattern to be searched The pattern can be a variable hexadecimal character a character or a string value The character pattern must be enclosed within single quotes The string pattern must be enclosed within double quotes This parameter is mandatory The Snumfound variable contains the number of patterns matched within the given memory address range 14 14 Command to Search for a Pattern in the Memory Address Space 197 Example 14 1 Sample Output for the find command cat example c include lt stdio h gt
236. g gdb set complain if sigtrap disabled on Also make certain the following warning was not emitted by the debugger before your program hung Warning Thread d in process d has disabled SIGTRAPs Debugging this thread is probably impossible If you do not want to see this message again use set complain if sigtrap disabled 0 info signals info handle Print a table of all the kinds of signals and how GDB has been told to handle each one You can use this to see the signal numbers of all the defined types of signals info handle isan alias for info signals handle signal keywords Change the way GDB handles signal signal signal can be the number of a signal or its name with or without the SIG at the beginning The keywords say what change to make The keywords allowed by the handle command can be abbreviated Their full names are nostop GDB should not stop your program when this signal happens It may still print a message telling you that the signal has come in stop GDB should stop your program when this signal happens This implies the print keyword as well print GDB should print a message when this signal happens noprint GDB should not mention the occurrence of the signal at all This implies the nostop keyword as well 68 Stopping and Continuing pass GDB should allow your program to see this signal your program can handle the signal or else it may terminate if the signal is fatal and not handled
237. g and switches back to them when you continue running your program Following commands are used for redirecting the input and output info terminal Displays information recorded by GDB about the terminal modes your program is using tty Another way to specify where your program should do input and output is with the tty command This command accepts a file name as argument and causes this file to be the default for future run commands It also resets the controlling terminal for the child process for future run commands For example tty dev ttyb directs that processes started with subsequent run commands default to do input and output on the terminal dev ttyb and have that as their controlling terminal 4 5 Working directory 43 E NOTE You can redirect your program input and output using shell redirection with the run command For example run gt outfile starts your program diverting its output to the file outfile e An explicit redirection in run overrides the tty command s effect on the input output device but not its effect on the controlling terminal e When you use the tty command or redirect input in the run command only the input for your program is affected The input for GDB still comes from your terminal 4 7 Debugging a Running Process You can use GDB to debug a running process by specifying the process ID Following commands are used to debug a running process attach process id This command attache
238. g inline functions in HP 9000 systems complete the following steps 1 Compile the source files with the inline debug option For example opt aCC bin acc g inline debug test c 2 Inline debugging is enabled by default To explicitly enable or disable inline de bugging complete either of the following steps before loading the application to the debugger gdb inline lt on off gt a out or gdb set inline debug lt on off gt 150 HP UX Configuration Specific Information 3 You can use the following commands for debugging inline functions in HP 9000 systems step next list backtrace frame lt n gt info locals info args The following commands are not available for debugging inline functions in HP 9000 systems breakpoint info frame disassembly 2 NOTE Inline debugging commands are not available for inlined template functions and inlined functions which are defined after the call site 14 8 2 Inline Debugging in Integrity Systems In Integrity systems applications that are compiled with g option support inline debugging by default Compiler versions A 06 02 and later support the inline debugging feature in Integrity systems and require no additional options WDB 5 6 and later versions enable you to set and modify breakpoints in inline functions for programs compiled with optimization level less than O2 The breakpoint features for inline functions are introduced as additional options in the set inli
239. gdb la regs gdb 15 3 Screen Layouts 247 15 4 Cycling through the panes Use the commands la next and la prev to move from one pane to another without specifying a window name If you specify la next repeatedly the order the debugger uses is e Source src e Disassembly asm e Source Disassembly split e Source Register e Disassembly Register If you invoked the gdb command with the xdb option as well as the tui option you can also use the following commands td Toggle between Source and Disassembly Register panes td Toggle split screen mode 15 5 Changing pane focus The command pane always has keyboard focus so that you can enter debugger commands If there is only one other pane Source or Disassembly the other pane has the logical focus so that you can scroll within that pane by using the arrow keys or the Page Up and Page Down keys on some keyboards these are Prev and Next A NOTE In the command pane the scrolling behavior only works for an hpterm and z not for an xterm or dtterm If you are in split screen mode you may want to change the logical focus of the pane To do so use the command focus win_name prev next where win name can be src asm regs or cmd Remember if you change the focus to a pane other than the command pane you need to use focus cmd to switch back to the command pane to enter or scroll through commands For example with the sequence of com
240. good one But do not omit the necessary information such as the test case on the assumption that a patch is all we need We might see problems with your patch and decide to x the problem another way or we might not understand it at all Sometimes with a program as complicated as GDB it is very hard to construct an example that will make the program follow a certain path through the code If you do not send us the example we will not be able to construct one so we will not be able to verify that the bug is fixed And if we cannot understand what bug you are trying to x or why your patch should be an improvement we will not install it A test case will help us to understand A guess about what the bug is or what it depends on Such guesses are usually wrong Even we cannot guess right about such things without first using the debugger to nd the facts 22 2 How to report bugs 363 364 A Installing GDB If you obtain GDB WDB as part of the HP ANSI C HP ANSI C Developer s Kit for HP UX Release 11 x or HP Fortran you do not have to take any special action to build or install GDB If you obtain GDB WDB from an HP web site you may download either an swinstall package or a source tree or both Most customers will want to install the GDB binary that is part of the swinstall package To do so use a command of the form usr sbin swinstall s package name WDB Alternatively it is possible to build GDB from the source di
241. hared libraries in the program 338 The GDB MI Interface GDB command The corresponding GDB command is info shared Example N A The file list symbol files command Synopsis file list symbol files List symbol files GDB command The corresponding GDB command is info file part of it Example N A The file symbol file command Synopsis file symbol file file Read symbol table info from the specified file argument When used without arguments clears GDB s symbol table info No output is produced except for a completion notification GDB command The corresponding GDB command is symbol file Example gdb file symbol file kwikemart marge ezannoni TRUNK mbx hello mbx done gdb 21 8 Miscellaneous GDB commands in GDB MI The gdb exit command Synopsis gdb exit 21 8 Miscellaneous GDB commands in GDB MI 339 Exit GDB immediately GDB command Approximately corresponds to quit Example gdb gdb exit The gdb set command Synopsis gdb set Set an internal GDB variable GDB command The corresponding GDB command is set Example gdb gdb set foo 3 done gdb The gdb show command Synopsis gdb show Show the current value of a GDB variable GDB command The corresponding GDB command is show Example gdb gdb show annotate done value 0 gdb The gdb version command Synopsis gdb version 340 The GDB MI Interface Show ver
242. he execution control to the user and prints a warning message when this condition is detected cv multiple mxs on off The set thread check cv multiple mxs on of command checks if an application 184 HP UX Configuration Specific Information cv wait no mx on off thread exit own mutex on off uses the same condition variable in multiple calls by different threads to pthread_cond_wait orpthread_cond_timedwait but specifies different mutexes The debugger transfers the execution control to the user and prints a warning message when this condition is detected All threads that concurrently wait on any single condition variable must specify the same associated mutex For example the pthread implementation does not allow thread 1 to waiton condition variable Aby specifying mutex A while thread 2 waits on the same condition variable Aby specifying mutex B This returns an EINVAL error to the application In contrast to this obvious EINVAL error the cv multiple mxs option detects the less obvious and non concurrent use of multiple mutexes with the same condition variable by different threads This option detects potential EINVAL errors that exist as a result of different timings or execution paths This option is used to detect unintentional use of multiple mutexes with the same condition variable by different threads In the case of applications that use a dynamic pool of mutexes the cv multiple mxs option is not req
243. he program stopped will be printed as well GDB command The corresponding GDB command is stepi Example gdb exec step instruction running gdb 2 Ngu stopped reason end stepping range thread id 1 frame addr 0x000029dc func call args name a name b file hello c line 16 gdb exec step instruction running gdb stopped reason end stepping range frame addr 0x000100f4 func foo args file try c line 10 gdb The exec until command Synopsis exec until location Asynchronous command Executes the inferior until the location specified in the argument is reached If there is no argument the inferior executes until a source line 336 The GDB MI Interface greater than the current one is reached The reason for stopping in this case will be location reached GDB command The corresponding GDB command is until Example gdb exec until recursive2 c 6 running gdb x 55 stopped reason location reached thread id 1 frame addr 0x00002a24 func main args file recursive2 c line 6 gdb The file exec and symbols command Synopsis file exec and symbols file Specify the executable file to be debugged This file is the one from which the symbol table is also read If no file is specified the command clears the executable and symbol information If breakpoints are set when using this command with no arguments GD
244. he calling function or j ump see Continuing at a different address page 120 to go to an arbitrary location in your program A typical technique for using stepping is to set a breakpoint see Breakpoints page 51 at the beginning of the function or the section of your program where a problem is believed to lie run your program until it stops at that breakpoint and then step through the suspect area examining the variables that are interesting until you see the problem happen Stopping and Continuing step step count next count finish Continue running your program until control reaches a different source line then stop it and return control to GDB This command is abbreviated s WARNING Ifyou use the step command while control is within a function that was compiled without debugging information execution proceeds until control reaches a function that does have debugging information Likewise it will not step into a function which is compiled without debugging information To step through functions without debugging information use the stepi command described below The step command only stops at the first instruction of a source line This prevents the multiple stops that could otherwise occur in switch statements for loops and so on step continues to stop if a function that has debugging information is called within the line In other words step steps inside any functions called within the li
245. he execution of the inferior program until a breakpoint is encountered or until the inferior exits GDB command The corresponding GDB is continue Example exec continue running gdb Hello world stopped reason breakpoint hit bkptno 2 thread id 1 frame addr 0x000029d8 func foo args file hello c line 16 file hello c line 13 gdb 21 7 GDB MI program control 331 The exec finish command Synopsis exec finish Asynchronous command Resumes the execution of the inferior program until the current function is exited Displays the results returned by the function GDB command The corresponding GDB command is finish Example Function returning void exec finish running gdb hello from foo stopped reason function finished thread id 1 frame addr 0x000029ec func main args file hello c line 7file hello c line 7 gdb Function returning other than void The name of the internal GDB variable storing the result is printed together with the value itself exec finish running gdb stopped reason function finished thread id 1 frame addr 0x000107b0 func foo args name a name b file recursive2 c line 14 gdb result var 1 return value 0 gdb The exec interrupt command Synopsis exec interrupt Asynchronous command Interrupts the background execution of the target Note how the token associated with t
246. he fork function When a program forks GDB will continue to debug the parent process and the child process will run unimpeded If you have set a breakpoint in any code which the child then executes the child will get a SIGTRAP signal which unless it catches the signal will cause it to terminate However if you want to debug the child process there is a workaround which isn t too painful Put a call to sleep in the code which the child process executes after the fork It may be useful to sleep only if a certain environment variable is set or a certain file exists so that the delay need not occur when you do not want to run GDB on the child While the child is sleeping use the ps program to get its process ID Then tell GDB a new invocation of GDB if you are also debugging the parent process to attach to the child process see Debugging a Running Process page 44 From that point on you can debug the child process just like any other process which you attached to On HP UX 11 x and later only GDB provides support for debugging programs that create additional processes using the fork or vfork function By default when a program forks GDB will continue to debug the parent process and the child process will run unimpeded If you want to follow the child process instead of the parent process use the command set follow fork mode 4 10 Debugging programs with multiple processes 49 set follow fork mode mode Set the debugger respon
247. he gdb prompt Following is the syntax for the unwind all frames command set unwind all frames on off where on Enables WDB to unwind beyond 10000 frames off Disables the limitation on the number of frames 206 HP UX Configuration Specific Information 14 18 Invoking GDB Before a Program Aborts This crashdebug option enables GDB to monitor the execution of a process or a program It invokes GDB when the program execution is about to abort Once the debugger is invoked you can debug the application using the normal debugger commands This option enables you to debug a live process instead of getting a core dump if the program is about to abort You can examine the state of the process make changes to the state and continue program execution force a core dump or terminate execution It enables you to control program execution under the debugger if the program is about to abort You can load anew process or attach to a running process for monitoring To monitor a new process enter the following command gdb crashdebug lt command gt lt options gt To monitor a running process attach to the process using the following command gdb crashdebug pid lt pid gt 14 19 Aborting a Command Line Call When a command line call is issued and it is interrupted by a breakpoint or a signal before completing the program execution the abort command enables the user to abort the command line call without allowing the signal to
248. he local variables and parameters in a function currently active on the stack e Ifyou xa routine in a file that contains function pointers those function pointers become invalid and will likely cause the program to receive a SIGSEGV error if the pointers are used e You cannot change the type of a local variable file static global variable or parameter of a function e You cannot add any function calls that increase the size of the parameter area e You cannot change a local or file static or global variable to be a register variable and vice versa 146 HP UX Configuration Specific Information e You cannot add an alloca function to a frame that did not previously use alloca e New structure fields can be added at the end of a structure object not in the middle of a structure New fields are only accessible by the modified files Old structure fields remain intact no swapping of them is permitted e If the redefined function is in the call stack but not on the top of the call stack the modified code will not be executed when the execution resumes The modified function will be executed when it is called next time or a rerun e Breakpoints in the original source file are moved to the modified fie Breakpoints in the already instantiated functions on the call stack in the original file are lost e If you change the name of a function and there was a breakpoint set to the old function WDB does not move the breakpoint to the
249. he same freed block could be subsequently allocated to the application in response to another memory allocation request In this scenario if the application incorrectly tries to write into the freed memory block using the dangling pointer it could result in incorrect or an undefined program behavior as the new owner or function owning the same allocated block would nd different values in the heap block 14 10 Debugging Memory Problems 175 A 4 NOTE Software literature names this concept as premature free or Reading writing freed memory using a pointer WDB tracks the dangling pointers and dangling blocks using a modified version of Garbage collection The enabler for doing this is by retaining all the freed blocks internally within RTC without actually freeing it as long as possible It displays all the potential pointers to the freed dangling blocks in the application data space The pointers are potential because the pointers need not be actual pointers and could be a datum value and hence there are chances of false positives in the dangling report NOTE WDB tries to help as much as possible to detect if these pointers are of type datum or real pointers Ina g compiled binary WDB performs a look up on a symbol table to nd the symbol name and type to nd the symbol name of the potential pointer and if its of pointer type then the corresponding dangling block is really dangling not a false positive WDB turns on these c
250. he stop message is the one for the execution command that has been interrupted The token for the interrupt itself only appears in the done output If the user is trying to interrupt a non running program an error message will be printed GDB command The corresponding GDB command is interrupt 332 The GDB MI Interface Example gdb 111 exec continue 111 running gdb 222 exec interrupt 222 done gdb 111 stopped signal name SIGINT signal meaning Interrupt frame addr 0x00010140 func foo args file try c line 13 gdb gdb exec interrupt error msg mi_cmd_exec_interrupt Inferior not executing gdb The exec next command Synopsis exec next Asynchronous command Resumes execution of the inferior program stopping when the beginning of the next source line is reached GDB command The corresponding GDB command is next Example exec next running gdb stopped reason end stepping range thread id 1 frame addr 0x00002a10 func main args file hello c line 24 gdb The exec next instruction command Synopsis exec next instruction Asynchronous command Executes one machine instruction If the instruction is a function call continues until the function returns If the program stops at an instruction in the middle of a source line the address will be printed as well GDB command The corresponding GDB command is next i 21 7 GDB MI progra
251. hecks only when you specify set heap check retain freed blocks on 14 10 8 6 Detect in block corruption of freed blocks HP WDB detects all the attempts of a program to write to the freed dangling blocks using dangling pointers We detect such in block corruptions and are reported as part of the existing info corruption command output 14 10 8 7 Specify the amount of guard bytes for every block of allocated memory HP WDB enables you to programmatically control the size of guard bytes for every block of the allocated memory You can use these guard bytes to spot very rare and non trivial boundary buffer over run and buffer under run corruptions This again is available optionally when the user specifies set heap check retain freed blocks lt on gt 14 10 9 Comparison of Memory Debugging Commands in Interactive Mode and Batch Mode HP WDB 5 6 and later versions provide consistency in format for the batch mode options and the interactive mode commands The following table lists the memory debugging commands available in batch and interactive mode 176 HP UX Configuration Specific Information Table 14 1 Memory Debugging Commands in Interactive and Batch Mode Command Description Toggles heap profiling and detection of leaks bounds and double free Interactive mode set heap check on off Batch mode check _heap on off or set heap check on off Toggle the leak detection capability set heap check
252. hen using source languages that permit overloading of symbols such as CH function may refer to more than one possible place to break See Breakpoint menus page 62 for a discussion of that situation Set a breakpoint some number of lines forward or back from the position at which execution stopped in the currently selected stack frame See Stack frames page 71 for a description of stack frames Set a breakpoint at line 1inenum in the current source file The current source file is the last file whose source text was printed The breakpoint will stop your program just before it executes any of the code on that line Set a breakpoint at line 1inenum in source file filename Set a breakpoint at entry to function function found in file filename Specifying a fie name as well as a function name is superfluous except when multiple files contain similarly named functions Set a breakpoint at address address You can use this to set breakpoints in parts of your program which do not have debugging information or source files When called without any arguments break sets a breakpoint at the next instruction to be executed in the selected stack frame see Chapter 6 page 71 In any selected frame but the innermost this makes your program stop as soon as control returns to that frame This is similar to the effect of a finish command in the frame inside the selected frame except that finish break if cond
253. hen you start GDB it executes commands from its init files These are files named gdbinit on UNIX During startup GDB does the following Read the init file if any in your home directory Process command line options and operands Read the init file if any in the current working directory Read the init file if any in the tmp directory if the GDB_PROCESS TMP _GDBINIT environment variable is set 5 Read command files specified by the x option PUNG The init file in your home directory can set options such as set complaints that affect subsequent processing of command line options and operands Init files are not executed if you use the nx option see Choosing modes page 27 It can be useful to create a gdbinit file in the directory where you are debugging an application This file will set the actions that apply for this application For example one might add lines like dir usr src path to source files to add source directories or break fatal to set breakpoints on fatal error routines or diagnostic routines On some configurations of GDB the init file is known by a different name these are typically environments where a specialized form of GDB may need to coexist with other forms hence a different name for the specialized version s init file These are the environments with special init file names 18 3 Command files 289 e VxWorks Wind River Systems real time OS vxgdbinit e OS68K
254. here symbol is stored GDB command The corresponding GDB command is info address Example N A The symbol info file command Synopsis symbol info file Show the file for the symbol GDB command There is no equivalent GDB command gdbtk has gdb_find_file Example N A The symbol info function command Synopsis symbol info function Show which function the symbol lives in GDB command gdb_get_function in gdbtk Example N A 346 The GDB MI Interface The symbol info line command Synopsis symbol info line Show the core addresses of the code for a source line GDB command The corresponding GDB command is info line gdbtk has the gdb_get_line and gdb get file commands Example N A The symbol info symbol command Synopsis symbol info symbol addr Describe what symbol is at location addr GDB command The corresponding GDB command is info symbol Example N A The symbol list functions command Synopsis symbol list functions List the functions in the executable GDB command info functions in GDB gdb listfunc and gdb search in gdbtk Example N A The symbol list types command Synopsis symbol list types 21 10 GDB MI Symbol query commands 347 List all the type names GDB command The corresponding commands are info types in GDB gdb_search in gdbtk Example N A The symbol list variables command Synopsis symbol list va
255. his more useful the message Program exited normally which is ordinarily issued whenever a program running under GDB control terminates is not issued when running in batch mode No windows If GDB comes with a graphical user interface GUI built in then this option tells GDB to only use the command line interface If no GUI is available this option has no effect If GDB includes a GUI then this option requires it to be used if possible Run GDB using directory as its working directory instead of the current directory Support additional dbx commands including e use e status in dbx mode status has a different meaning than in default GDB mode e whereis func e file e assign e call d stop GNU Emacs sets this option when it runs GDB as a subprocess It tells GDB to output the full file name and line number in a standard recognizable fashion each time a stack frame is displayed which includes each time your program stops This recognizable format looks like two 032 characters followed by the file name line number and character position separated by colons and a newline The Emacs to GDB interface program uses the two 032 characters as a signal to display the source code for the frame The Epoch Emacs GDB interface sets this option when it runs GDB as a subprocess It tells GDB to modify its print routines so as to allow Epoch to display values of expressions in a separate window annotat
256. hread primitives 187 14 11 4 Debugging Threads Interactively After Attaching to a Process 187 14 11 5 Thread Debugging in Batch Mod esc vor tivities Caisyn eta eialcaiees 189 14 11 5 1 Pre requisites for Batch mode of Thread Debugging ccceeeeeeee 190 14 11 5 2 Limitations in Batch mode of thread debugging cee eee esos 193 14 11 6 Thread Debugging in check Mod eis cis hnteitie penton sputind atietindeitevseteoiiees 193 14 11 7 Known issues with Thread Debugging for Interactive and Batch mode 194 14 12 Webu pene MPI Proc rann Siac jve case beees coves kites ee AEA EEE EAE A EEEE 194 14 13 Debugging multiple processes programs with fork and vfork calls 195 14 13 1 Ask mode for set follow fork mode essssssseerrsreessssesrreeeesessesseees 195 14 13 2 Serial mode for set follow fork mode s s e ssssesserrsrsessssesrereeesesseseeees 195 14 13 3 Support for showing unwind ILO lt asssccsersassacenvscdiane vaadeceushidcenrsentespriverncwnavess 195 14 13 4 Printing CFM and PFS Tee Ste rs ios cess cavncedcncds ictus eet anntliawe ontieiuststetenenrincers 196 14 14 Command to Search for a Pattern in the Memory Address Space ccccecee 196 14 15 Debup sing Core Piles Pesser gpi orea eaa an ae ss ue EARE a seca aE EESE i 200 14 15 1 Generating core files with packcore unpackcore getCOre cece 200 Table of Contents 7 8 14 15 2 Support for the info target Command sins sev
257. ies loaded into the stripped executable when you are in the right scope 14 35 3 2 Backtrace on stripped frames GDB should be able to backtrace properly stripped frames Arguments will not be displayed as in the case of non g binary If it is a fully archived stripped binary function names will not be displayed but PCs will be 14 35 3 3 Command line calls to non stripped library Command line calls to the functions exported symbols in the stripped binary work fine Command line calls to the non stripped library work normally regardless where the process is stopped 14 35 3 4 Setting breakpoints in unstripped shared library GDB will not be able to put breakpoints using symbolic names of the symbols not in export list or line numbers in the stripped modules GDB will be able to place breakpoints using symbol names in the unstripped shared libraries loaded into the stripped executable 240 HP UX Configuration Specific Information 14 36 Displaying the current block scope information The which command takes a symbol as an argument and prints the information on a given symbol It prints the following information e current block scope addresses e line information of the definition of the symbol e filename in which the definition of the symbol occurs The which command does not work for global and type symbols since they do not contain line information Syntax which lt symbol gt For example gdb which i Line 4 of examp
258. ific Information ccis sancivssscscnapaidiesses saveernetonnasrsaneertpaadersconcemmninnsenss 137 14 1 Summary of HP Enhancements to GDB wiavssiiscssnessstvensvvincetdendsediedes ess cans ent siunyancens 137 14 2 HP UX d pendencies cae ices avila bas iira ear aret D SEke EEEE EEEE VEEE EEEE REES 140 142 1 Linker Dependencies rrsan irn raa E E A AAEE A EEEN 140 14 2 2 Dependent Standard Library Routines for Run Time Checking 0004 140 i453 Supported Platforms and MOGs uieri cies eset ehie circ ta o raaes 142 TAA HP UX targets naen neia a TA EE E A atresia ts EA E T nde suadsunteders ei 143 14 5 Support for Alternate root ssesnisis ienas ieaie enra ieii E E EER aE iA i ie 143 14 6 Specifying object file directories ssssssnsseseseesessessesserttsessesesssensessessesessesrensesees 144 14 7 Fix and continue debugging ericae aa i aia tiis 145 14 7 1 Fix and Continue compiler dependencies sesssesssssessessrsseessersreseesserssesees 146 14 7 2 Fix and Continue restricHonS naro akik ak A EEEa rE ERLA ECEAT EEL AiE ari 146 14 7 3 Using Fix and Contin e ensisi irie i ipni esaia E ETTE aay NiE ar s 147 14 7 4 Example Fix and Continue SOSSION i adeiss oie esnexssecdervidessaedeeebaewkecaveeaseaaareeeaeess 148 14 8 Inline St pp Orta sciacins easton taaichel hyve sania Sova elev cobain asy va e ssid Nava aa an Mav ae aaas 150 14 8 1 Inline Debugging in HP 9000 Sy Stem S s isis inssesrosessssoveasestwmnaberynnasvaszentaante ev
259. ilar to the HOME xdbhist file The history file is not saved until the end of your debugging session To change the name of the history file use set history filename To stop recording use set history save off To display the current history status use show history For an equivalent of the XDB record all facility pipe the output of the gdb command to the tee 1 command For example gdb a out tee mylogfile This solution works with the default line mode user interface not with the terminal user interface The following table lists the XDB and the equivalent WDB commands for handling macros 16 2 8 Macro facility commands Use the show user or help user defined command to obtain a list of all user defined commands 264 XDB to WDB Transition Guide Table 16 13 Macro facility commands XDB Command WDB Equivalent def name replacement text def name GDB prompts for commands Meaning Define a user defined command tm No equivalent Toggle the macro substitution mechanism undef name def name follow with empty command list Remove the macro definition for name undef 16 2 9 Signal control commands No equivalent Remove all macro definitions The following table lists the XDB and equivalent WDB commands for signal control Table 16 14 Signal control commands XDB Command E2 z number s WDB Equivalent 1z with xdb info signals z number s with xdb
260. ill not support Command line calls of intrinsic functions Mathematical functions like cos sin log etc e Decimal Floating Point data type support for Fortran and C e HP UX 1liv2 Integrity and HP 9000 systems 14 24 Additional Support for binary floating point data type 14 24 1 Support for Binary Floating Point constants f If the binary floating point constant contains the letter f or 1 then HP WDB recognizes it as float or long double binary floating point constant Generally a floating point constant without f or l is considered as double binary floating point constant gdb p lt num gt lt f 1 gt This prints the binary floating point constant depending upon its data type 14 24 2 Support Binary Floating Point variables with format specifier HP WDB versions 5 9 and later provide the following format specifiers for binary floating point variables which print the variables in the specified binary floating point format gdb p f lt var name gt This prints the binary floating point value as oat gdb p db lt var name gt This prints the binary floating point value as double gdb p l lt var name gt This prints the binary floating point value as long double 216 HP UX Configuration Specific Information 14 25 Language support 14 25 1 Enhanced Java Debugging Support HP WDB shows stack traces of mixed Java C and C programs It supports unwinding across Java frames and provides an effective way to examine
261. indicates that you wish special formatting and also acts as an index to pick an element of the list If the list element is a string the number to be inserted 294 Using GDB under gnu Emacs is formatted using the Emacs function format otherwise the number is passed as an argument to the corresponding list element In any source file the Emacs command C x SPC gdb break tells GDB to set a break point on the source line point is on If you accidentally delete the source display buffer an easy way to get it back is to type the command f in the GDB buffer to request a frame display when you run under Emacs this recreates the source buffer if necessary to show you the context of the current frame The source files displayed in Emacs are in ordinary Emacs buffers which are visiting the source files in the usual way You can edit the files with these buffers if you wish but keep in mind that GDB communicates with Emacs in terms of line numbers If you add or delete lines from the text the line numbers that GDB knows cease to correspond properly with the code 295 296 20 GDB Annotations This chapter describes annotations in GDB Annotations are designed to interface GDB to graphical user interfaces or other similar programs which want to interact with GDB at a relatively high level 20 1 What is an annotation To produce annotations start GDB with the annotate 2 option Annotations start with a newline character two
262. ine terminated by an end The commands 18 1 User defined commands 287 are executed repeatedly as long as the expression evaluates to true document commandname Document the user defined command commandname so that it can be accessed by help The command commandname must already be defined This command reads lines of documentation just as define reads the lines of the command definition ending with end After the document command is finished help on command commandname displays the documentation you have written You may use the document command again to change the documentation of a command Redefining the command with define does not change the documentation help user defined List all user defined commands with the first line of the documentation if any for each show user show user Display the GDB commands used to define commandname commandname but not its documentation If no commandname is given display the definitions for all user defined commands When user defined commands are executed the commands of the definition are not printed An error in any command stops execution of the user defined command If used interactively commands that would ask for confirmation proceed without asking when used inside a user defined command Many GDB commands that normally print messages to say what they are doing omit the messages when used in a user defined command 18 2 User defined command hooks You may define hooks
263. ing 004 167 14 10 5 3 Example for Batch Mode RC sx sscscvcssessswassnanecsentsimecesetndecseataailiacenseveesens 169 14 10 6 Debugging Memory Interactively After Attaching to a Running Process 171 14 10 7 Configuring memory debugging settings ccecccccseeseeee cess srsecseeeeeeeeeees 173 1410 7 Specityinie th stack depth iseseisana iniaiaiai 173 14 10 7 2 Specifying minimum leak siZe s ssssssessssseseesesesressssesssssesresessesrensesees 173 14 10 7 3 Specifying minimum block size ssesssessessessserssrsessserssisessreessissreseesse 174 6 Table of Contents 14108 Scenarios in memory eM ae OI Basis sees ssactev bn retusa goedeney mensenveeenbeoneeeentbee 174 14 10 8 1 Stop when freeing unallocated or deallocated DIOCKS cceeeeeees 174 14 10 8 2 Stop when freeing a block if bad writes occurred outside block boundary terenne eve retentive cele EA E e nese EEA Ea ARE A e ea 174 14 10 8 3 Stop when a specified block address is allocated or deallocated 175 14 10 8 4 Scramble previous memory contents at malloc free calls 175 14 10 8 5 Detect dangling pointers and dangling DIOCKS c cece eeeeeee eee 175 14 10 8 6 Detect in block corruption of freed DIOCKS ceccecseseesseesseeeteneeeseenes 176 14 10 8 7 Specify the amount of guard bytes for every block of allocated PVC TONY sescz cnt ete arab tEn E ASEE ES EENE EAE EEE E a RER REE e EE EEE REEE 176 14 10 9 Comparison
264. ing GDB expression debugging info Turns on or o display of GDB C overload debugging info This includes info such as ranking of functions etc The default is o Displays the current state of displaying GDB C overload debugging info Turns on or o display of reports on all packets sent back and forth across the serial line to the remote machine The info is printed on the GDB standard output stream The default is o Displays the state of display of remote packets Turns on or o display of GDB serial debugging info The default is o Displays the current state of displaying GDB serial debugging info Turns on or o display of GDB target debugging info This info includes what is going on at the target level of GDB as it happens The default is o Displays the current state of displaying GDB target debugging info Turns on or o display of GDB variable object debugging info The default is o 17 7 Optional messages about internal happenings 285 show debug varobj Displays the current state of displaying GDB variable object debugging info 286 Controlling GDB 18 Canned Sequences of Commands In addition to breakpoint commands see Breakpoint command lists page 61 GDB provides the following two ways to store sequence of commands for execution as a unit e user defined commands e command files 18 1 User defined commands A user defined command is a sequence of GDB commands to which you assign a new name as a
265. ing i n Shift lt Keys gt osfRight string 0xlb string la Mouse operations are not supported in the tui mode Also the paging and shift keys do not work well with VT100 14 31 6 Changing the size of the source or debugger pane 1 Escape to vi command mode first 2 Drag the status bar using the mouse If you are using tui mode use these commands to change the size of the current window CTRL W to increase CTRL W to decrease In Visual Interface for WDB the current window is usually the debugger window 236 HP UX Configuration Specific Information 14 31 7 Using commands to browse through source files browse For example CTRL B CTRL F CTRL D CTRL U are useful for browsing the debugger window These commands work whether or not you escape to vi mode These vim commands require you to escape to vi mode For example T Search forward SN Search backward nN Repeat search Ye Match braces TT Skip to the next procedure line number Go to any line number All these commands require you to escape to vi command mode first When you are done type a for append or i for insert or other vi commands to return to text insertion mode Or you can simply click the Prompt softkey 14 31 8 Loading source files Escape to vi command mode and use the e command to load a source file e filename When the source files are located in multiple directories you can simply specify the
266. inked with MxN pthreads library are emulated under ARIES as traditional 1x1 threads and thus can only be debugged under ARIES as any other non MxN multi threaded application e ARIES supports debugging of 32 bit and 64 bit HP 9000 HP UX applications using 32 bit HP 9000 HP UX GDB 64 bit HP 9000 HP UX gdb is not supported under ARIES 14 30 2 Attaching GDB to an already running emulated process You can attach GDB to an already running HP 9000 application process on HP UX 11i for HP Integrity servers to debug the application After a successful attach all of the GDB commands work in exactly the same manner as they do on an HP 9000 HP UX server Use the steps below to attach GDB to HP 9000 application process under ARIES on HP UX 11i Integrity servers e Perform the same preparatory steps as required for debugging an HP 9000 HP UX application using GDB under ARIES on HP UX 11i Integrity server e Invoke GDB as follows gdb lt pa_process name gt lt pa_process_ name gt You can also invoke GDB through any of the attach modes supported by GDB using the pid lt pa_pid gt option or by issuing the attach lt pa_pid gt command at the gdb prompt After the debugging the process can continue or abort as specified by the user This feature is especially useful when triaging problems in an environment with a large number of processes and a mix of Integrity native and HP 9000 processes 14 30 3 Detecting memory leaks using GDB under ARIE
267. innermost one and so on The highest numbered frame is the one for main frame addr Select the frame at address addr This is useful mainly if the chaining addr of stack frames has been damaged by a bug making it impossible for GDB to assign numbers properly to all frames In addition this can be useful when your program has multiple stacks and switches between them 6 5 Selecting a frame 73 A NOTE e Onthe SPARC architecture frame needs two addresses to select an arbitrary frame a frame pointer and a stack pointer e On the MIPS and Alpha architecture it needs two addresses a stack pointer and a program counter e On the 29k architecture it needs three addresses a register stack pointer a program counter and a memory stack pointer up n Move n frames up the stack For positive numbers n this advances toward the outermost frame to higher frame numbers to frames that have existed longer n defaults to one down n Move n frames down the stack For positive numbers n this advances toward the innermost frame to lower frame numbers to frames that were created more recently n defaults to one You may abbreviate down as do All of these commands end by printing two lines of output describing the frame The first line shows the frame number the function name the arguments and the source file and line number of execution in that frame The second line shows the text of that source line For example gdb
268. ints e Running the Executable under GDB e Stepping to the next line e Stepping into a Subroutine e Examining the Stack e Printing Variable Values e Listing the Source Code e Setting Variable Values During a Debug Session In this sample session we emphasize user input like this input to make it easier to pick out from the surrounding output One of the preliminary versions of GNU m4 a generic macro processor exhibits the following bug sometimes when we change its quote strings from the default the commands used to capture one macro definition within another stop working In the following short m4 session we define a macro foo which expands to 0000 we then use the m4 built in defn to define bar as the same thing However when we change the open quote string to lt QUOTE gt and the close quote string to lt UNQUOTE gt the same procedure fails to define a new synonym baz cd gnu m4 change your current directory to the location where the m4 executable is stored m4 run the m4 application define foo 0000 foo 0000 define bar defn foo bar 0000 changequote lt QUOTE gt lt UNQUOTE gt define baz defn lt QUOTE gt f 00 lt UNQUOTE gt baz Cc d m4 End of input 0 fatal error EOF in string 1 1 Loading the Executable Let us use GDB to try to see what is going on 1 1 Loading the Executable 19 gdb m4 HP gdb 3 0 for PA RISC 1 1 or 2 0 narrow HP UX 11 00 Copyright 1986 20
269. ion The thread terminates execution and the resources associated with the terminated thread continues to exist in the application because the thread has not been joined or detached The thread uses more than the specified percentage of the stack allocated to the thread The number of threads waiting on any pthread object exceeds the specified thresh old number 14 11 3 1 Pre requisites for Advanced Thread Debugging The following pre requisites apply for advanced thread debugging The advanced thread debugging features are supported only on HP UX 11i v2 and later on both PA RISC and Integrity systems The tracing pthread library is required for advanced thread debugging The pthread tracer library is available by default on systems running on HP UX 11i v2 or later You must install HP WDB 5 5 or later versions of the debugger to support enhanced thread debugging The installation scripts for HP WDB 5 5 and later versions of the debugger automatically add links at opt langtools 1lib to replace the standard libpthread library with libpthread tracer library at run time The thread debugging feature in HP WDB is dependent on the availability of the dynamic Linker Version B 11 19 HP WDB uses librtc s1 to enable thread debugging support If the debugger is installed in a directory other than the default opt langtools bin directory you must use the environment variable LIBRTC_SERVER to export the path of the appropriate version of librt
270. ion is performed before the variable is used in an expression when appearing after it the value of the variable is used before the operation takes place Pointer dereferencing Defined on pointer types Same precedence as Address operator Defined on variables Same precedence as For debugging C GDB implements a use of amp beyond what is allowed in the C language itself you can use amp amp ref or if you prefer simply amp amp ref to examine the address where a C reference variable declared with amp ref is stored Negative Defined on integral and floating point types Same precedence as Logical negation Defined on integral types Same precedence as Bitwise complement operator Defined on integral types Same precedence as Structure member and pointer to structure member For convenience GDB regards the two as equivalent choosing whether to dereference a pointer based on the stored type information Defined on struct and union data Dereferences pointers to members Array indexing a i is defined as a i Same precedence as gt Function parameter list Same precedence as gt 9 4 Supported languages 107 C scope resolution operator Defined on struct union and class types Double colons also represent the GDB scope operator see Expressions page 83 Same precedence as above If an operator is redefined in the user code GDB usually att
271. is enabled only for one stop The catchpoint is automatically deleted after the first time the event is caught Use the info break command to list the current catchpoints There are currently some limitations to C exception handling catch throw and catch catch in GDB e Ifyou call a function interactively GDB normally returns control to you when the function has finished executing If the call raises an exception however the call may bypass the mechanism that returns control to you and cause your program either to abort or to simply continue running until it hits a breakpoint catches a signal that GDB is listening for or exits This is the case even if you set a catchpoint for the exception catchpoints on exceptions are disabled within interactive calls e You cannot raise an exception interactively e You cannot install an exception handler interactively Sometimes cat ch is not the best way to debug exception handling if you need to know exactly where an exception is raised it is better to stop before the exception handler is called since that way you can see the stack before any unwinding takes place If you set a breakpoint in an exception handler instead it may not be easy to find out where the exception was raised To stop just before an exception handler is called you need some knowledge of the implementation In the case of GNU C exceptions are raised by calling a library functionnamed _ _ raise_exception which has the
272. is not specified the debugger displays the complete table of execution path entries starting from start_index If start_index and end_index are not specified the complete table of execution path entries is displayed e info global exec path summary Prints the summary information about all the global execution path entries in the current frame This command displays the total number of global execution path entries that can be stored the number of global execution path entries in this frame in the last iteration and the last executed global execution path number e exec path up down path index aliased to ep Enables you to select print and navigate through the execution path entries When no arguments are specified it prints the selected execution path entry You can specify the argument as an execution path index from the info exec path or the info global exec path commands Alternately you can use the up or down command to navigate through the execution path entries 14 16 1 Compiler Dependencies for Printing the Execution Path Entries The pathtrace compiler option provides a mechanism to record program execution control flow into global path tables local path tables or both This saved information enables the debugger to print the execution path entries in the current thread or frame To print the execution path entries in the current thread or frame for programs running on Integrity systems you can set the requir
273. is searched earlier GDB recognizes two special directory names cdir which refers to the compilation directory if available and cwd which tracks GDB s current working directory objectload file c Causes GDB to load the debug information for file c immediately The default is to load debug information from object modules on demand objectretry file c Forces GDB to retry loading an object file if GDB encounters a file error while reading an object module File errors that might cause this include incorrect permissions file not found or if the objectdir path changes By default GDB does not try to read an object file after an error pathmap Enables you to define a list of substitution rules to be applied to path names to identify object files and the corresponding source files The pathmap command 144 HP UX Configuration Specific Information however may not find source files if the object files are not available This minimizes or eliminates the need to specify multiple obj ectdir commands when object files are moved from the compilation directories or when compilation directories are mounted over NFS To use this feature the program must be compiled with the obj debug option For information on how pathmap works type help pathmap at the HP WDB prompt If the debugger cannot find the source files perform the following steps 1 Make certain the files were compiled with the g switch Type info sources to nd the list
274. ister while execution is going on in that frame GDB assigns numbers to all existing stack frames starting with zero for the innermost frame one for the frame that called it and so on upward These numbers do not really exist in your program they are assigned by GDB to give you a way of designating stack frames in GDB commands One of the stack frames is selected by GDB and the GDB commands refer implicitly to the selected frame In particular whenever you ask GDB for the value of a variable in your program the value is found in the selected frame There are special GDB commands to select whichever frame you are interested in See Selecting a frame page 73 When your program stops GDB automatically selects the currently executing frame and describes it briefly similar to the frame command see Information about a frame page 74 6 1 Stack frames 71 6 2 Stacks Without frames Some compilers provide a way to compile functions so that they operate without stack frames For example the gcc option fomit frame pointer generates functions without a frame This is occasionally done with heavily used library functions to save the frame setup time GDB has limited facilities for dealing with these function invocations If the innermost function invocation has no stack frame GDB nevertheless regards it as though it had a separate frame which is numbered zero as usual allowing correct tracing of the function call chain
275. ith version number B 11 19 or higher is required for debugging memory problems e From HP WDB 5 7 onwards the archive version of the run time check library librtc a is not available You must use the shared version of the library librtc sl sol instead 14 10 3 Memory Debugging Methodologies WDB enables you to debug memory problems in applications written for HP UX 11 x or later using C aC FORTRAN 77 and Fortran 90 WDB provides several commands that help expose memory related problems 158 HP UX Configuration Specific Information HP WDB offers the following memory debugging capabilities Reports memory leaks Reports heap allocation profile Stops program execution if bad writes occur with string operations such as st rcpy and memcpy Stops program execution when freeing unallocated or de allocated blocks Stops program execution when freeing a block if bad writes occur outside block boundary Stops program execution conditionally based on whether a specified block address is allocated or de allocated Scrambles previous memory contents at malloc and free calls Simulates and detects out of memory event errors Detects dangling pointers and dangling blocks Detects in block corruption of freed blocks Specifies the amount of guard bytes for every block of allocated memory Displays the run time type information for C polymorphic objects You can use any of the following methods to identify memory problems S
276. itions if you are stepping by machine instructions variables may appear to have the wrong values until the stack frame is completely built On exit it usually also takes more than one machine instruction to destroy a stack frame after you begin stepping through that group of instructions local variable definitions may be gone This may also happen when the compiler does significant optimizations To be sure of always seeing accurate values turn o all optimization when compiling Another possible effect of compiler optimizations is to optimize unused variables out of existence or assign variables to registers as opposed to memory addresses Depending on the support for such cases offered by the debug info format used by the compiler GDB might not be able to display values for such local variables If that happens GDB will print a message like this No symbol foo in current context To solve such problems either recompile without optimizations or use a different debug info format if the compiler supports several such formats For example GCC the GNU C C compiler usually supports the gstabs option The gstabs produces debug information in a format that is superior to formats such as COFF You may be able to use DWARF 2 gdwarf 2 which is also an effective form for debug info See Compiling for debugging page 39 8 3 Artificial arrays It is often useful to print out several successive objects of the same
277. its float f off 480 bits len 32 bits 14 25 3 Support for __ fpreg data type on IPF WDB internally converts _ fpreg data type to long double data type to evaluate an expression or to print the value of the expression Since long double data type has only 15 bit exponent as opposed to 17 bitexponent of _ _ fpreg some precision is lost when the exponent is larger than that can t in 15 bits 14 25 4 Support for Complex variables in HP C HP Con Itanium systems supports a Complex data type built from any of the floating point types A Complex number holds a pair of floating point numbers the first is the real part and the second is the imaginary part Here are examples of declarations and initializations using _Complex numbers float Complex glob float _complex double _Complex glob double complex 6 long double Complex glob long double complex Imaginary I __float80 Complex glob float80 complex 8 9 Imaginary I _Imaginary_I is a keyword which represents the square root of 1 The debugger has limited support for _Complex variables No arithmetic operations are allowed with Complex numbers A _Complex number may be cast or assigned to any numeric data type and vice versa A _Complex variable can be initialized with an expression of the form A B Imaginary I where A and B are ordinary numeric expressions perhaps in parentheses This is also the format in which the debugger displays a Complex value
278. kely to want to repeat The 1ist and x commands when you repeat them with RET construct new arguments rather than repeating exactly as typed This permits easy scanning of source or memory e GDB can also use RET in another way to partition lengthy output in a way similar to the common utility more see Setting the GDB Screen Size page 283 Since it is easy to press one RET too many in this situation GDB disables command repetition after any command that generates this sort of display e Any text from a to the end of the line is a comment it does nothing This is useful mainly in command files see Command files page 289 3 2 Command completion GDB can fill in the rest of a word in a command for you if there is only one possibility it can also show you what the valid possibilities are for the next word in a command at any time This works for GDB commands GDB subcommands and the names of symbols in your program Press the TAB key whenever you want GDB to fill out the rest of a word If there is only one possibility GDB fills in the word and waits for you to finish the command or press RET to enter it For example if you type gdb info bre TAB 3 1 Command syntax 33 34 GDB fills in the rest of the word breakpoints since that is the only info subcommand beginning with bre gdb info breakpoints You can either press RET at this point to run the info breakpoints command or backspace and
279. kpoint of the given number sb disable Suspend all breakpoints sb shared library No equivalent Suspend breakpoints in named shared library GDB does not provide the ability to set breakpoints on all procedures with a single command Therefore it does not have any equivalent of the following commands bp bpt bpx dp Dpt Dpx 16 2 5 Global breakpoint commands The following table lists the XDB and equivalent WDB commands for setting global breakpoints Table 16 12 Global breakpoint commands XDB Command WDB Equivalent abc cmds No exact equivalent but abc print expr Meaning Set or delete cmds to execute at display expr is equivalent to every stop dbc undisplay 16 2 Overall breakpoint commands Stop displaying values at each stop 263 16 2 6 Assertion control commands GDB does not provide the ability to trace by instruction Watchpoints however provide similar functionality to xdb assertions For example watchpoints can be e Enabled corresponds to aa e Disabled corresponds to da e Listed corresponds to info watch e Added corresponds to x WDB does not have explicit equivalents for the following commands a aa da la sa ta x 16 2 7 Record and playback commands Use the source command to read commands from a file GDB does not provide a recording capability like XDB s but you can use the set history save command to record all GDB commands in the file gdb_history sim
280. le c block starts at address 0x29a8 lt main gt and ends at 0x29e4 lt main 0x3c gt 14 37 Linux support Linux Runtime Environment LRE on HP UX Itanium enables users to execute Intel Itanium Linux applications on HP UX HP WDB provides a prototype for LRE debugging which allows you to debug applications ported from Linux that run under LRE This provides a minimal debugging capability for LRE 14 36 Displaying the current block scope information 241 242 15 The HP UX Terminal User Interface By default GDB runs in line mode For users who prefer an interface similar though not identical to that of the XDB debugger HP provides a terminal user interface TUI which appears when you invoke the gdb command with the tui option Use the xdb option to enable the use of a number of XDB commands See the XDB to WDB Transition Guide page 253 15 1 Starting the TUI Invoke the debugger using a command like the following gdb xdb tui a out These examples use the default terminal screen size of 24 by 80 characters Following is a sample terminal screen window 31 Try two test cases 32 print_average my_list first last 33 print_average my_list first last 3 Ww OV File average c Procedure Line pc Wildebeest is free software covered by the GNU General Public License and you are welcome to change it and or distribute copies of it under certain conditions Type show copying to see
281. le gt For 64 bit IPF applications iD_PRELOAD opt langtools lib hpux64 librtc so lt executable gt For 64 bit PA applications LD_PRELOAD opt langtools lib pa20_64 librtc sl lt executable gt 192 HP UX Configuration Specific Information If LD_PRELOAD and chatr rtc are used to preload the librtc runtime library the 1ibrtc runtime library is loaded from the path specified by LD PRELOAD If HP WDB detects any thread error condition during the application run the error log is output to a file in the current working directory The output file has the following naming convention lt executable name gt lt pid gt threads where lt pids is the process id 14 11 5 2 Limitations in Batch mode of thread debugging The feature does not obtain the thread error information in batch mode for forked process in a multiprocessing application However if the 1ibrtc s1 library is preloaded the debugger obtains the thread error information in the batch mode for exec ed application You cannot specify an alternate output directory for the thread error log The thread error log file is output into the current working directory only HP WDB cannot execute both batch mode thread check and batch mode heap check together If the rtcconfig file has both entries then batch heap check overrides the batch thread check 14 11 6 Thread Debugging in check Mode A A new compiler option check thread enables batch mode
282. leaks on off check_leaks on off or set heap check leaks on off Toggle validation of calls to strcpy strncpy memcpy memccpy memset memmove bzero and bcopy set heap check string on off check _string on off or set heap check string on off Toggle validation of calls to free set heap check free on off check free on off or set heap check free on off Specify whether freed blocks should set heap check scramble blocks on off or be scrambled scramble on off set heap check scramble on off Toggle bounds check on heap blocks set heap check check bounds on off bounds on off or set heap check bounds on off Specify the minimum size of a block for stack trace collection GDB will report blocks of size greater than or equal to lt num gt at each call site set heap check min heap size lt num gt min_heap_size lt num gt or set heap check min heap size lt num gt Specify the minimum size of a block for stack trace collection GDB report leaks of blocks smaller than this value However no stack trace is provided Specify the depth of call stack to be captured set heap check min leak size lt num gt set heap check frame count lt num gt min_leak_size lt num gt or set heap check min leak size lt num gt frame_count lt num gt or set heap check frame count lt num gt Instruct GD
283. lementary since core files contain only the contents of the program read write memory variables machine status etc While the executable files contain only the program text and initialized data When you type run your executable file becomes an active process target as well When a process target is active all GDB commands requesting memory addresses refer to that target addresses in an active core file or executable file target are obscured while the process target is active Use the core file and exec file commands to select a new core file or executable target see Commands to specify files page 125 To specify as a target a process that is already running use the attach command see Debugging a Running Process page 44 13 2 Commands for managing targets target type parameters Connects the GDB host environment to a target machine or process A target is typically a protocol for talking to debugging facilities You use the argument type to specify the type or protocol of the target machine Further parameters are interpreted by the target protocol but typically include things like device 13 1 Active targets 133 help target help target name set gnutarget args show gnutarget names or host names to connect with process numbers and baud rates The target command does not repeat if you press RET again after executing the command Displays the names of all targets available To display targets c
284. les 2 The rtcconfig file must contain entries such as the following check _heap on check _leaks on check _free on files executable name output dir tmp results 3 Set the following environment variables as follows export BATCH _RTC on 14 10 Debugging Memory Problems 169 4 Complete one of the following steps Map the shared libraries privately using chatr as follows chatr dbg enable lt executable gt On HP UX 11i v3 Integrity systems WDB enables automatic debugging of shared libraries without them being mapped private while attaching to arunning program For enabling automatic debugging of shared libraries you must install the kernel patches PHKL_38651 and PHKL_38778 Explicitly preload the 1ibrtc runtime library and start the target application as follows LD _PRELOAD opt langtools lib librtc sl lt executable gt lt arguments gt OR Set the target application to preload librtc by using the rtc option for the chatr command In addition to automatically loading the librtc library the rtc option for the chatr command also maps the shared libraries as private To set the target application to preload the 1ibrtc runtime library enter the following command at the HP UX prompt chatr rtc enable lt executable gt e Example for Batch Mode RTC on Integrity Systems Example 1 1 Compile the source files 2 The rtcconfig file must contain entries such as the following check _heap on check_leak
285. level of details of information required to be displayed when debugging memory leaks 14 10 7 1 Specifying the stack depth Memory debugging reduces the performance of an application by 20 40 because of stack unwinding To provide a clear profile of every allocation in the program the debugger collects the stack trace information for every allocation in the debugged application Reducing the stack depth the number of stack frames that the debugger collects for each allocation reduces the performance degradation The set heap check frame count command enables you to control the depth of the stack frames that are collected by WDB for each allocation By default four stack frames are displayed from the allocating call stack To set the depth of the stack frames that is collected by WDB enter the following command at the gdb prompt set heap check frame count num The stack depth num is the number of stack frames that WDB collects for each allocation You can specify a higher value for num to view more stack frames for each reported allocation However the performance of the application is reduced because of the increased stack depth 14 10 7 2 Specifying minimum leak size WDB enables you to specify the minimum leak size for stack trace collection to improve the program s performance Stack trace collection slows down the program because it occurs on every allocation call Therefore if the program is allocation intensive
286. llowed you can use expressions like count aml gt GetOriginal x y While a member function is active in the selected stack frame your expressions have the same namespace available as the member function that is GDB allows implicit references to the class instance pointer this following the same rules as CH You can call overloaded functions GDB resolves the function call to the right definition with some restrictions GDB does not perform overload resolution involving user defined type conversions calls to constructors or instantiations of templates that do not exist in the program It also cannot handle ellipsis argument lists or default arguments It does perform integral conversions and promotions floating point promotions arithmetic conversions pointer conversions conversions of class objects to base classes and standard conversions such as those of functions or arrays to pointers it requires an exact match on the number of function arguments Overload resolution is always performed unless you have specified set overload resolution off See GDB features for C page 111 You must specify set overload resolution off in order to use an explicit function signature to call an overloaded function as in p foo char int x 13 The GDB command completion facility can simplify this Refer to Command completion page 33 GDB understands variables declared as C references you can use them in expressions j
287. looks like this flags 29000041 ri 51a800 rp 7 6ce597 r3 7 7 0000 r4 1 r5 7 7 06f4 r6 7 7 06fc r7 7 7 0800 r8 7 7 0800 r9 40006b10 r10 0 r11 40004b78 12 21 r13 0 r14 0 ELS 30 r16 40003fb8 r17 4 246 The HP UX Terminal User Interface ee gt 0x3524 lt main 8 gt addil L 0x800 dp r1 0x3528 lt main 12 gt ldo 0x730 r1 r26 O0x352c lt main 16 gt ldi 9 r24 0x3530 lt main 20 gt ldi 0 r25 0x3534 lt main 24 gt ldil L 0x3000 r31 EE E E ye eam me E E E EEE E E E A oe File average c Procedure main Line 32 pe gdb Starting program Breakpoint 1 gdb gdb gdb gdb 1 print_average my_list first home work wdb a out main at average c 32 la asm la split la regs last 0x3524 15 3 5 Source Register pane The Source Register pane appears when you issue the command la regs when the current pane is the Source pane The screen looks like this flags 29000041 rl 51a800 rp 7f6ce597 r3 7 7f0000 r4 1 r5 7f7f06f4 r6 7 7f06fc r7 7 7 0800 r8 7f7f0800 r9 40006b10 r10 o r11 40004b78 r12 1 r13 0 r14 0 r15 0 r16 40003 b8 r17 4 gt 32 print_average my_list first last 33 print_average my_list first last 3 34 35 36 37 EN NENE E EENE ach E ss E EENE ENE S ESE E EE EE E A E File average c Procedure main Line 32 pc 0x3524 Breakpoint 1 main at average c 32 gdb la asm gdb la split gdb la regs gdb la sre
288. lowing options are available for the macro_debug compiler option all To view and evaluate all the macro expressions in the program you must compile the program with macro_debug a11 This option can cause a significant increase in object file size ref To view and evaluate only the reference macros in the program you must compile the program with macro_debug ref This is the default for g g0 or gl none To disable macro debugging you must compile the program with macro_ debug none 154 HP UX Configuration Specific Information The macro debugging features are supported for obj debug and noobj debug compiler options 14 9 2 Examples for Macro Debugging The following example illustrates the use of the macro debugging Sample Program cat scope c include lt stdio h gt define USED1 100 define USED2 200 define UNUSED1 0 define UNUSED2 0 define DUMMY1 9 define DUMMY2 ANAHAUNBRWNE DW 11 int 12 main 13 15 int val USED1 17 undef UNUSED1 18 undef USED2 19 undef USED1 20 define USED1 101 21 define USED2 201 23 val USED1 USED2 25 undef USED1 26 undef UNUSED2 27 undef USED2 28 define USED1 102 29 30 val USED1 31 32 return 0 33 Sample Debugging Session e The following debugging session illustrates macro debugging when the program is com piled with macro_debug al11 option cc g macro_debug all o sc scope c gdb sc HP gdb for HP Itaniu
289. ls from tmp info target Local core dump file tmp core file type elf64 big 0x6000000000000000 0x6000000000010000 is segment4 PT_HP CORE LOADABLE ox9ffffffffb7d9000 ox9ffffffffb7da000 is segment5 PT_HP_CORE_MMF ox9ffffffffb7da000 ox9ffffffffb7dc000 is segment6 PT_HP_CORE_MMF ox9ffffffffb7dc000 Ox9ffffffffb7e0000 is segment7 PT_HP_CORE_MMF ox9ffffffffb7e0000 Ox9ffffffffb7e8000 is segment8 PT_HP_CORE_MMF ox9ffffffffb7e8000 Ox9ffffffffb7f3000 is segment9 PT_HP_CORE_MMF Oox9ffffffffb7f3000 Ox9ffffffffb7f4000 is segment10 PT_HP_CORE_MMF Oox9ffffffffb7f4000 Ox9ffffffffb7f6000 is segment11 PT_HP_CORE_MMF ox9ffffffffb7f6000 ox9ffffffffb7fa000 is segment12 PT_HP_CORE_MMF ox9ffffffffb7fa000 Ox9ffffffffb7fc000 is segment13 PT_HP_CORE_MMF ox9ffffffffb7fc000 Ox9ffffffffb7fe000 is segment14 PT_HP_CORE_MMF ox9ffffffffb7fe000 Ox9ffffffffb7ff000 is segment15 PT_HP_CORE_MMF ox9ffffffffb7ff000 Ox9ffffffffb800000 is segment16 PT_HP_CORE_STACK RSE ox9fffffffffffa000 0xa000000000000000 is segment17 PT_HP_CORE_STACK 0x6000000000000058 0x600000000000d000 is heap segment Ox9fffffff7b7f6270 Ox9fffffff7b7f62e8 is note hpux options in usr lib hpux64 dld so Ox9fffffff7b7f62e8 Ox9fffffff7b7f6458 is dynamic in usr lib hpux64 dld so 14 15 Debugging Core Files 201 A NOTE Limitations for the enhanced info target command on corefile are as follows e Theenhanced info target command is not supported when the expanded_node_ho
290. lt executable name gt lt pid gt threads where lt pid gt is the process identifier 14 11 7 Known issues with Thread Debugging for Interactive and Batch mode Issue 1 During the execution of advanced thread checking for applications that fork in the interactive mode the following message appears if the GDB follows the child Pthread analysis file missing This error message appears because the thread error information for the forked process is not available However if the forked process exec s another binary the thread error information is available for the exec ed binary Issue 2 In both interactive and batch modes if the applications exceed their thread stack utilization the following error message appears Error accessing memory address This occurs when GDB attempts a command line call on an already overflowing thread stack 14 12 Debugging MPI Programs You can attach the debugger to Message Passing Interface MPI programs for debugging You must set the one of the following environment variables before you launch the MPI process set MPI FLAGS egdb for invoking GDB or set MPI FLAGS ewdb for invoking WDB For more information see the mpidebug 1 and mpienv 1 manpages Attaching the debugger to an MPI process or to any other process that has not been compiled for debugging can result in the following warning warning reading r3 register No data 194 HP UX Configuration Specific Information
291. lt main 44 gt ldi 6 r24 0x354c lt main 48 gt ldi 0 r25 File average c Procedure main Line 32 pc 0x3524 gdb b main Breakpoint 1 at 0x3524 file average c line 32 gdb r Starting program home work wdb a out Breakpoint 1 main at average c 32 gdb la asm gdb 15 3 Screen Layouts 245 15 3 3 Source Disassembly pane The Source Disassembly pane appears when you issue the command la split You can also reach this pane from the Source pane with the XDB command td The window looks like this gt 32 print_average my_list first last 233 print_average my_list first last 3 34 35 36 37 ee print average my_list first last gt 0x3524 lt main 8 gt addil L 0x800 dp Srl 0x3528 lt main 12 gt ldo 0x730 r1 r26 0x352c lt main 16 gt ldi 9 r24 0x3530 lt main 20 gt ldi 0 r25 0x3534 lt main 24 gt ldil L 0x3000 r31 PONP AANS PIENIN IENS eS NEIE PEEN BOPT IIR EN YR ETRE LO E Dy he ROR eal Mey et REY Ee een AEE Pa a OS S File average c Procedure main Line 32 pe 0x3524 Breakpoint 1 at 0x3524 file average c line 32 gdb r Starting program home work wdb a out Breakpoint 1 main at average c 32 gdb la asm gdb la split gdb 15 3 4 Disassembly Register pane The Disassembly Register pane appears when you issue the command la regs when the current pane is the Source Disassembly pane By default the debugger displays the general registers The window
292. ly contain only short strings The default is off set print pretty on Cause GDB to print structures in an indented format with one member per line like this 1 next 0x0 flags sweet 1 sour 1 92 Examining Data set print pretty off show print pretty set print sevenbit strings on set print sevenbit strings off show print sevenbit strings set print union on set print union off show print union bs meat 0x54 Pork Cause GDB to print structures in a compact format like this 1 next 0x0 flags sweet 1 sour 1 meat 0x54 Pork This is the default format Show which format GDB is using to print structures Print using only seven bit characters if this option is set GDB displays any eight bit characters in strings or character values using the notation nnn This setting is best if you are working in English ASCII and you use the high order bit of characters as a marker or meta bit Print full eight bit characters This allows the use of more international character sets and is the default Show whether or not GDB is printing only seven bit characters Tell GDB to print unions which are contained in structures This is the default setting Tell GDB not to print unions which are contained in structures Ask GDB whether or not it will print unions which are contained in structures For example given the declarations typedef enum Tree Bug
293. m 32 or 64 bit and target HP UX 11 2x Copyright 1986 2001 Free Software Foundation Inc 14 9 Debugging Macros 155 gdb b 13 Breakpoint 1 at 0x40007d0 0 file scope c line 13 from sc gdb b 23 Breakpoint 2 at 0x40007d0 2 file scope c line 23 from sc gdb b 30 Breakpoint 3 at 0x40007e0 0 file scope c line 30 from sc gdb r Starting program sc Breakpoint 1 main at scope c 13 13 gdb print USED1 100 gdb print USED1 10 110 gdb info macro USED1 Defined at scope c 4 define USED1 100 gdb info macro USED2 Defined at scope c 5 define USED2 200 gdb c Continuing Breakpoint 2 main at scope c 23 23 val USED1 USED2 gdb info macro USED1 Defined at scope c 20 define USED1 101 gdb info macro USED2 Defined at scope c 21 define USED2 201 gdb c Continuing Breakpoint 3 main at scope c 30 30 val USED1 gdb info macro USED1 Defined at scope c 28 define USED1 102 gdb info macro USED2 The macro USED2 has no definition in the current scope gdb The following debugging session illustrates macro debugging when the program is com piled with macro_debug referenced option cc g macro_debug referenced o scl scope c gdb scl HP gdb for HP Itanium 32 or 64 bit and target HP UX 11 2x Copyright 1986 2001 Free Software Foundation Inc gdb b 13 Breakpoint 1 at 0x40007d0 0 file scope c line 13 from scl gdb b 23 156 HP UX
294. m the arguments of the call and the local variables of the function being called The information is saved in a block of data called a stack frame The stack frames are allocated in a region of memory called the call stack The GDB commands for examining the stack allow you to view all of this information 6 1 Stack frames The call stack is divided up into contiguous pieces called stack frames or frames for short each frame is the data associated with one call to one function The frame contains the arguments given to the function the local variables and the address at which the function is executing When your program is started the stack has only one frame that of the function main This is called the initial frame or the outermost frame Each time a function is called a new frame is made Each time a function returns the frame for that function invocation is eliminated If a function is recursive there can be many frames for the same function The frame for the function in which execution is actually occurring is called the innermost frame This is the most recently created of all the stack frames that still exist Inside your program stack frames are identified by their addresses A stack frame consists of many bytes each of which has its own address each kind of computer has a convention for choosing one byte whose address serves as the address of the frame Usually this address is kept in a register called the frame pointer reg
295. m control 333 Example gdb exec next instruction running gdb stopped reason end stepping range thread id 1 frame addr 0x00002a14 func main args file hello c line 24 gdb The exec return command Synopsis exec return Makes current function return immediately Does not execute the inferior Displays the new current frame GDB command The corresponding GDB command is return Example gdb break insert calli done bkpt number 1 type breakpoint disp keep enabled y addr 0x000029ac func calli file hello c line 9 times 0 gdb exec run running gdb nn stopped reason breakpoint hit bkptno 1 thread id 1 frame addr 0x000029ac func calli args name a file hello c line 9 gdb exec return nn a atgu done frame level 0 addr 0x000029e8 func call args name a name b file hello c line 17 gdb The exec run command Synopsis exec run Asynchronous command Starts execution of the inferior from the beginning The inferior executes until either a breakpoint is encountered or the program exits GDB command The corresponding GDB command is run 334 The GDB MI Interface Example gdb break insert main done bkpt number 1 type breakpoint disp keep enabled y addr 0x00002a08 func main file hello c line 23 times 0 gdb exec run running gdb stopped
296. m s main function To make WDB automatically start running the target program add these lines to your startup file gdbinit break main run 15 3 Screen Layouts The TUI supports four panes within the terminal window in various combinations e Command e Source e Disassembly e Register 244 The HP UX Terminal User Interface The Command pane is always present The possible configurations of the other panes are e Source e Disassembly e Source Disassembly e Disassembly Register e Source Register The layout command abbreviated 1a enables you to change from one window configuration to another A NOTE You can abbreviate any command to its shortest unambiguous form 15 3 1 Source pane The Source pane Figure 1 appears by default when you invoke the debugger You can also make it appear by issuing the command la srce 15 3 2 Disassembly pane The Disassembly pane appears when you issue the command la asm The pane looks like this iii print_average my_list first last gt 0x3524 lt main 8 gt addil L 0x800 dp r1 0x3528 lt main 12 gt ldo 0x730 r1 r26 0x352c lt main 16 gt ldi 9 r24 0x3530 lt main 20 gt ldi 0 r25 0x3534 lt main 24 gt ldil L 0x3000 r31 0x3538 lt main 28 gt be 1 0x498 sr4 r31 0x353c lt main 32 gt copy r31 rp print_average my_list first last 3 0x3540 lt main 36 gt addil L 0x800 dp r1 0x3544 lt main 40 gt ldo 0x730 r1 r26 0x3548
297. m through the mmap system call you can use another option mapped to cause GDB to write the symbols for your program into a reusable file Future GDB debugging sessions map in symbol information from this auxiliary symbol file if the program has not changed rather than spending time reading the symbol table from the executable program Using the mapped option has the same effect as starting GDB with the mapped command line option You can use both options together to make sure the auxiliary symbol file has all the symbol information for your program The auxiliary symbol file for a program called myprog is called myprog syms Once this file exists so long as it is newer than the corresponding executable GDB always attempts to use it when you debug myprog no special options or commands are needed The syms file is specific to the host machine where you run GDB It holds an exact image of the internal GDB symbol table It cannot be shared across multiple host platforms Specify the whereabouts of a core dump file to be used as the contents of memory Traditionally core files contain only some parts of the address space of the process that generated them GDB can access the executable file itself for other parts core file with no argument specifies that no core file is to be used Note that the core file is ignored when your program is actually running under GDB So if you have been running your program and y
298. m you experience is a fatal signal you should still say so explicitly Suppose something strange is going on such as your copy of GDB is out of synch or you have encountered a bug in the C library on your system This has happened Your copy might crash and ours would not If you told us to expect a crash then when ours fails to crash we would know that the bug was not happening for us If you had not told us to expect a crash then we would not be able to draw any conclusion from our observations Here are some things that are not necessary 362 Reporting Bugs in GDB A description of the envelope of the bug Often people who encounter a bug spend a lot of time investigating which changes to the input file will make the bug go away and which changes will not affect it This is often time consuming and not very useful because the way we will nd the bug is by running a single example under the debugger with breakpoints not by pure deduction from a series of examples We recommend that you save your time for something else Of course if you can nd a simpler example to report instead of the original one that is a convenience for us Errors in the output will be easier to spot running under the debugger will take less time and so on However simplification is not vital if you do not want to do this report the bug anyway and send us the entire test case you used A patch for the bug A patch for the bug does help us if it is a
299. mal floating point variable This assigns decimal floating point value to the variable according to its data type Arithmetic Operations gdb print a opl b gdb print op2 a opl addition subtraction multiplication and division op2 negation This performs arithmetic operation with decimal floating point data types Comparison Operations gdb p lt dfp val gt op lt dfp val gt where op gt gt lt lt If expression contains comparison operation then GDB compares the decimal floating point data types accordingly gdb p 1 2dd 1 2dd gdb 2 4 14 23 4 1 Printing type of Decimal Floating Point variable gdb ptype lt dfp const gt lt dfp var gt This prints the type of the Decimal floating point variable or constant gdb ptype 1 22dd type Decimal64 14 23 Debugging support for Decimal Floating Point datatype 215 Conversion of types GDB handles conversion of data types during assignment printing and arithmetic and comparison operation gdb p 1 2df 1 2dd This converts double data type 1 2 to _Decimal 64 data type and performs addition operation with _Decimal64 data type 1 2dd and prints value in _Decimal 4 type HP WDB handles exceptions such as overflow infinity and division by zero for Decimal Floating Point data type gdb print 1 2dd 0 gdb inf HP WDB handles finite infinite and NaN Not a Number values of decimal floating point data type A NOTE HP WDB w
300. mands just issued you are in split screen mode with the focus in the Source pane The pane with logical focus has a border constructed from and A pane that does not have logical focus has a border constructed from vand 248 The HP UX Terminal User Interface flags 29000041 rl 51a800 rp 7 6ce597 r3 7 7 0000 r4 1 r5 7 7 06 4 r6 7f7f06fc r7 7 7 0800 r8 7 7 0800 r9 40006b10 r10 0 r11 40004b78 SEb2 1 r13 0 r14 0 r15 0 r16 40003fb8 r17 4 gt 32 print_average my_list first last 33 print_average my_list first last 3 3a o 35 36 jaa 2 2222 22222 22222222222 noe enna ene n File average c Procedure main Line 32 pe 0x3524 Breakpoint 1 main at average c 32 gdb la asm gdb la split gdb la regs gdb la sre gdb la regs gdb By default the Source pane can scroll To change the focus so that you can scroll in the Register pane use the focus command abbreviated foc or fs fs regs or foc next If you then use the Page Down key to scroll in the Register pane the window looks like this flags 29000041 ri 51a800 rp 7 6ce597 r3 7 7 0000 r4 1 r5 7 7 06f4 r6 7 7 06fc r7 7 7 0800 r8 7 7 0800 r9 40006b10 r10 0 r11 40004b78 r12 1 r13 0 r14 0 ri5 0 r16 40003fb8 r17 4 gt 32 print_average my_list first last 233 print _average my_list first last 3 34 35 36 37 File average c Pro
301. mmand GDB does not understand references to a function in a shared library unless you are debugging a core file When you specify a breakpoint using a name that GDB does not recognize the debugger warns you with a message that it is setting a deferred breakpoint on the name you specified If any shared library is loaded with a matching name then GDB sets the breakpoint For example if you type break foo the debugger does not know whether foo is a misspelled name or whether it is the name of a routine that has not yet been loaded from a shared library The debugger displays a warning message that it is setting a deferred breakpoint on foo If any shared library is loaded that contains a foo then GDB sets the breakpoint If this is not what you want for example if the name was mistyped then you can delete the breakpoint 14 22 3 Using catch load The catch load lt libname gt command causes the debugger to stop when the particular library is loaded This gives you a chance to set breakpoints before routines are executed 14 22 4 Privately mapping shared libraries In cases where you attach to a running program and you try to set a breakpoint in a shared library GDB may generate the following message The shared libraries were not privately mapped setting a breakpoint in a shared library will not work until you rerun the program GDB generates this message because the debugger sets breakpoints by replacing an instru
302. modify the state of the debugged process When a signal interrupts program execution it can modify the process state of the de bugged program and result in an abrupt termination of the program due to addressing errors from a call that is not a part of the source program In such cases the abort command is particularly useful in exiting the command line call without modifying the process state of the debugged program The following example illustrates the use of the abort command gdb break main Breakpoint 1 at 0x2c74 file address_error c line 41 gdb run Starting program address_error Breakpoint 1 main at address_error c 41 41 fun count count 1 1 gdb p fun 10 1 1 Program received signal SIGBUS Bus error si_code 0 BUS UNKNOWN Unknown Error 0x2c38 in fun i 10 f 0 at address_error c 37 37 count p The program being debugged was signaled while in a function called from GDB GDB remains in the frame where the signal was received To change this behavior use set unwindonsignal on Evaluation of the expression containing the function fun will be abandoned gdb bt 0 0x2c38 in fun i 10 f 0 at address_error c 37 1 0x1920 in _sr4export 0x8 2 lt function called from gdb gt 3 0x2c74 in main at address error c 40 gdb abort 14 18 Invoking GDB Before a Program Aborts 207 Abort gdb command line call y or n y 0 main at address_error c 41 41 fun c
303. mp print 1 2 n lt 1 3 n lt done lt gdb A bad command Here is what happens if you pass a bad command gt rubbish lt error msg Undefined MI command rubbish lt gdb 21 2 GDB MI compatibility with CLI To help users get familiar with GDB CLI GDB MI accepts existing CLI commands As specified by the syntax such commands can be directly entered into the GDB MI interface and GDB will respond This mechanism is provided as an aid to developers of GDB MI clients and not as a reliable interface into the CLI Since the command is being interpreted in an environment that assumes GDB MI behaviour the exact output of such commands is likely to end up being an un supported hybrid of GDB MI and CLI output 310 The GDB MI Interface 21 3 GDB MI output records 21 3 1 GDB MI result records In addition to a number of out of band notifications the response to a GDB MI command includes one of the following result indications done results J The synchronous operation was successful results are the return values running The asynchronous operation was successfully started The target is running terror c string The operation failed The c string contains the corresponding error message 21 3 2 GDB MI stream records 21 3 3 GDB internally maintains a number of output streams the console the target and the log The output intended for each of these streams is funneled thro
304. mp Java object e Print Java heap histogram e Find all the instances of a given Java class e Find all the references to a given object in the Java heap e Find out the object OOP object oriented pointer of the given field address These additional features are available as part of Java threads support e View Java threads state information e View current Java thread information e View Java interpreted frame monitors information 14 25 1 2 gdb Subcommands for Java VM Debugging Commands for Examining Java Virtual Machine JVM internals To view the gdb commands that support Java VM debugging type help java at the gdb prompt gdb help java Java and JVM debugging commands List of java subcommands java args Show the current or specified Java frame arguments info java bytecodes Disassemble the given Java method s bytecodes java heap histogram Show the Java heap object histogram java instances Find all the instances of the given klassOop in the Java heap java jvm state Show Java virtual machine s current internal states java locals Show the current or specified Java frame locals info java mutex info Print out details of the static mutexes java object Print out the given Java object s fields info java oop Find the Java object oop of the given Java heap address java references Find all the references to the given Java object in the Java heap java unwind info Show the unwind info of th
305. mpiled code for source line 1inespec You can specify source lines in any of the ways understood by the 1ist command see Printing source lines page 77 For example we can use info line to discover the location of the object code for the first line of function m4_changequote gdb info line m4_changequote Line 895 of builtin c starts at pc 0x634c and ends at 0x6350 We can also inquire using addr as the form for 1inespec what source line covers a particular address For example gdb info line 0x63ff Line 926 of builtin c starts at pc 0x63e4 and ends at 0x6404 After info line the default address for the x command is changed to the starting address of the line so that x i is sufficient to begin examining the machine code see Section 8 5 page 87 Also this address is saved as the value of the convenience variable _ see Section 8 9 page 96 disassemble This specialized command dumps a range of memory as machine instructions The default memory range is the function surrounding the program counter of the selected frame A single argument to this command is a program counter value GDB dumps the function surrounding this value Two arguments specify a range of addresses first inclusive second exclusive to dump Examining Source Files The following example shows the disassembly of a range of addresses of HP PA RISC 2 0 code gdb disas 0x32c4 0x32e4 Dump of assembler 0Ox32c4 0x32
306. n fprintf fscanf sscanf strcasecmp getcwd getpagesize getpid srand unlink uwx register callbacks lseek open sprintf strcmp printf pthread self putenv shmct1 strchr rand uwx self lookupip shl_ get shl_unload shl_ findsym strtok_ r time uwx get reg shl_ get _r perror uwx init uwx self copyin creat uwx_ step write uwx self init context pthread _getschedparam uwx self init info uwx register alloc _cb U_STACK_TRACE close strchr The runtime checking of dynamic memory libraries and pthreads in the debugger relies on the semantic and standard behavior of these library routines Run Time Checking results in unexpected and unpredictable behavior when used with applications that substitute or re define these library routines Before enabling the Run Time Checking feature in WDB use the nm 1 command to determine if the application or the dependent libraries in the application redefine or substitute these standard library routines 14 2 HP UX dependencies 141 14 3 Supported Platforms and Modes Supported Platforms HP WDB supports source level debugging of programs written in HP C HP aC and Fortran 90 on Integrity systems running on HP UX 11i v2 or later and PA RISC systems running HP UX 11i v1 and later Support for assembly level debugging HP WDB provides su
307. n The default setting is on You can set it to on to display messages 4 9 Debugging programs with multiple threads 47 48 show threadverbose Display whether set threadverbose is on or off Here are commands to get more information about threads info threads thread threadno thread apply threadno all args Running Programs Under GDB Display a summary of all threads currently in your program GDB displays for each thread in this order 1 the thread number assigned by GDB 2 the target system s thread identifier systag 3 the current stack frame summary for that thread 4 the priority of a thread An asterisk to the left of the GDB thread number indicates the current thread For example gdb info threads 3 system thread 26607 worker wptr 0x7b09c318 at quicksort c 137 2 system thread 26606 0x7b0030d8 in __ksleep from usr lib libc 2 1 system thread 27905 0x7b003498 in brk from usr lib libc 2 Make thread number threadno the current thread The command argument threadno is the internal GDB thread number as shown in the first field of the info threads display GDB responds by displaying the system identifier of the thread you selected and its current stack frame summary gdb thread 2 Switching to thread 2 system thread 26594 0x34e5 in sigpause As with the New message the form of the text after Switching to depends on your system s
308. n did the original support for encapsulated COFF Brent Benson of Harris Computer Systems contributed DWARF 2 support Adam de Boor and Bradley Davis contributed the ISI Optimum V support Per Bothner Noboyuki Hikichi and Alessandro Forin contributed MIPS support Jean Daniel Fekete contributed Sun 386i support Chris Hanson improved the HP 9000 support Noboyuki Hikichi and Tomoyuki Hasei contributed Sony News OS 3 support David Johnson contributed Encore Umax support Jyrki Kuoppala contributed Altos 3068 support Jeff Law contributed HP PA and SOM support Keith Packard contributed NS32K support Doug Rabson contributed Acorn Risc Machine support Bob Rusk contributed Harris Nighthawk CX UX support Chris Smith contributed Convex support and Fortran debugging Jonathan Stone contributed Pyramid support Michael Tiemann contributed SPARC support Tim Tucker contributed support for the Gould NP1 and Gould Powernode Pace Willison contributed Intel 386 support Jay Vosburgh contributed Symmetry support Andreas Schwab contributed M68K Linux support Rich Schaefer and Peter Schauer helped with support of SunOS shared libraries Jay Fenlason and Roland McGrath ensured that GDB and GAS agree about several machine instruction sets Patrick Duval Ted Goldstein Vikram Koka and Glenn Engel helped develop remote debugging Intel Corporation Wind River Systems AMD and ARM contributed remote debugging modules for the i960 VxWorks A29K UDI and
309. n keys on the keyboard to move the cursor e Pagination keys move the cursor in the source window at the top above the status line e Holding the shift key down while using the pagination keys moves the cursor in the debugger window e The up and down arrow keys move the cursor in the source window e Holding the shift key down while using the up and down arrow keys move the cursor in the debugger window e The left and right arrow keys move the cursor in the debugger window e Two rows of labeled softkeys at the bottom of the display give you quick access to common commands Visual Interface for WDB GUI display 33 include lt stdlib h gt 34 include Deck h 35 include Player h 36 include House h 37 38 int main 39 gt 40 srand int time 0 41 42 Deck theDeck 43 Player thePlayer 100 44 House theHouse 16 45 46 theHouse Instructions 47 File BlackJack C Function main Line 40 Pe O0x3ea0 wdb b main Breakpoint 1 at Ox3ea0 file BlackJack C line 40 wdb run Starting program work wdb blackjack blackjack Breakpoint 1 main at BlackJack C 40 40 srand int time 0 wdb 234 HP UX Configuration Specific Information Run Resume Stop Up Visual Finish Print Type List Interface for WDB Faq Stop Next Down Prompt Print Edit Credits You can click the softkey or press a function key on the keyboard to invoke the command The function keys F1 through F8 correspond to
310. n terms of the actual machine code until with no argument works by means of single instruction stepping and hence is slower than until with an argument Continue running your program until either the specified location is reached or the current stack frame returns location is any of the forms of argument acceptable to break see Setting breakpoints page 52 This form of the command uses breakpoints and hence is quicker than until without an argument stepi stepi arg Execute one machine instruction then stop and return to the si debugger It is often useful to do display i pc when stepping by machine instructions This makes GDB automatically display the next instruction to be executed each time your program stops See Automatic display page 89 An argument is a repeat count as in step nexti nexti arg Execute one machine instruction but if it is a function call ni proceed until the function returns An argument is a repeat count as in next 5 3 Signals A signal is an asynchronous event that can happen ina program The operating system defines the possible kinds of signals and gives each kind a name and a number For example in Unix SIGINT is the signal a program gets when you type an interrupt character often C c SIGSEGV is the signal a program gets from referencing a place in memory far away from all the areas in use SIGALRM occurs when the alarm clock timer goes off which happens only if yo
311. n the application if the thread is not joined or detached The thread must be explicitly joined or detached or it must be created with the detach attribute When an application repeatedly creates threads without a join or detach operation the application leaks resources This may result in application failure The set thread check stack util num command checks if any thread has used more than the specified percentage num of the stack allocation The debugger transfers the execution control to the user and prints a warning message when this condition is detected You can use this option to verify if there is a margin of safety in stack utilization by the threads The application must ensure that the thread stack size is sufficient for all the operations of the thread Each thread is assigned a stack allocation when it is created If the stack allocation is not specified for a thread the default value is used The stack allocation cannot be modified after a thread is created If a thread attempts to use more stack space than the allocated stack space it results in a stack overflow Stack over flow can result in memory access violations bus errors or segmentation faults num waiters num The set thread check num waiters num command checks if the number of threads waiting on any pthread object exceeds the specified threshold number num The debugger transfers the execution control to the user and prints a warning message when thi
312. nd location Execute to next source line in this function skipping all function calls like the GDB next command Then update the display window to show the current file and location Execute one instruction like the GDB stepi command update display window accordingly Execute to next instruction using the GDB next i command update display window accordingly Execute until exit from the selected stack frame like the GDB finish command Continue execution of your program like the GDB continue command WARNING In Emacs v19 this command is C c C p Go up the number of frames indicated by the numeric argument see section Numeric Arguments in The gnu Emacs Manual like the GDB up command WARNING In Emacs v19 this command is C c C u Go down the number of frames indicated by the numeric argument like the GDB down command WARNING In Emacs v19 this command is C c C d Read the number where the cursor is positioned and insert it at the end of the GDB I O buffer For example if you wish to disassemble code around an address that was displayed earlier type disassemble then move the cursor to the address display and pick up the argument for disassemble by typing C x amp You can customize this further by defining elements of the list gdb print command once it is defined you can format or otherwise process numbers picked up by C x amp before they are inserted A numeric argument to C x amp
313. ne Also the step command only enters a function if there is line number information for the function Otherwise it acts like the next command This avoids problems when using cc g1 on MIPS machines Previously step entered subroutines if there was any debugging information about the routine Continue running as in step but do so count times Ifa breakpoint is reached or a signal not related to stepping occurs before count steps stepping stops right away Continue to the next source line in the current innermost stack frame This is similar to step but function calls that appear within the line of code are executed without stopping Execution stops when control reaches a different line of code at the original stack level that was executing when you gave the next command This command is abbreviated n An argument count is a repeat count as for step The next command only stops at the first instruction of a source line This prevents multiple stops that could otherwise occur in switch statements for loops and so on Continue running until just after function in the selected stack frame returns Print the returned value if any Contrast this with the return command see Returning from a function page 121 5 2 Continuing and stepping 65 66 until u until location u location Stopping and Continuing Continue running until a source line past the current line in the current stack frame is reached This
314. ne numbers for each instruction EY NOTE The ipo compilation implies the noobj debug option because the ipo object files do not store executable code or debug info 14 30 Debugging with ARIES The ARIES fast interpreter emulates a complete set of non privileged PA RISC instructions with no user intervention During interpretation it monitors the applications 230 HP UX Configuration Specific Information execution pattern and translates only the frequently executed code into native Itanium R code at runtime 14 30 1 Debugging the application using GDB under ARIES ARIES supports debugging of HP 9000 HP UX applications on HP UX 11i Integrity servers using the HP 9000 HP UX GDB Both the GDB and the application run under ARIES No change in GDB user interface including WDB GUI Negligible loss of performance in interactive mode The HP 9000 GDB is included by default as part of the Integrity HP UX WDB GDB package All GDB commands work just like they would on an HP 9000 server Use the following steps to debug HP 9000 HP UX applications on HP UX 11i Integrity servers using GDB 1 2 Set the environment variable PA_DEBUG to 1 Set the environment variable SHELL to point to an HP 9000 shell copied from an HP 9000 HP UX system from usr bin path Add usr ccs bin to the PATH environment variable Invoke GDB as gdb PA RISC _ executable After the debugging is finished perform the following steps 1 2 3
315. ne debug command You can toggle the options for inline debugging by entering either of the following commands gdb set inline debug lt option gt or gdb inline lt option gt The following options available for the set inline debug command e on e off e inline bp all e inline_ bp individual The set inline debug on command enables the inline debugging feature without the inline breakpoints options in Integrity systems This command is enabled by default 14 8 Inline Support 151 The set inline debug off command disables the inline debugging feature You can disable inline debugging by entering this command before attaching the debugger to the application The set inline debug inline _bp_all command enables you to set and modify break points on all instances of a particular inline function It also enables the inline debugging feature A single instance of the specified inline function is displayed as a representative in stance for all the instances of the specified inline function This creates a single breakpoint illusion for multiple instances of the inline function You can set and modify breakpoints on all the instances of the inline functions by setting and modifying breakpoints on the displayed instance of the inline function You must enter this command before attaching the debugger to the application The set inline debug inline _bp_ individual command enables you to set and modify breakpoints on a specific instan
316. ng with xdb rev regexp No equivalent one command per line in command list var or var var cmd line cmd line with xdb she cmd line cmd_list commands number end lt file source file lt lt file No equivalent gt No equivalent gt file No equivalent gt C No equivalent gt f No equivalent gt t No equivalent gt c t No equivalent gt file No equivalent gt gt No equivalent gt gt file No equivalent gt gt No equivalent gt gt file No equivalent 278 XDB to WDB Transition Guide Table 16 30 Symbols continued XDB Command Equivalent WDB Command Control C Control C text text label No equivalent 16 8 Alphabetical lists of XDB commands and HP WDB equivalents 279 280 17 Controlling GDB You can alter the way GDB interacts with you by using the set command For commands controlling how GDB displays data see Print settings page 90 Other settings are described here 17 1 Setting the GDB Prompt A GDB indicates its readiness to read a command by printing a string called the prompt This string is normally gdb You can change the prompt string with the set prompt command For instance when debugging GDB with GDB it is useful to change the prompt in one of the GDB sessions so that you can always tell which one you are talking to NOTE set prompt does not add a
317. ng HP UX 11i v2 or later Steps to debug threads in batch mode 1 A 3 Compile the source files Set the LD_LIBRARY_PATH environment variable based on the platform as follows e For 32 bit IPF applications set LD LIBRARY PATH opt langtools wdb lib hpux32 e For 64 bit IPF applications set LD LIBRARY PATH opt langtools wdb lib hpux64 e For 64 bit PA applications set LD LIBRARY PATH opt langtools wdb lib pa20_ 64 Map the share libraries as private for HP 9000 systems using the following command chatr dbg enable lt executable gt NOTE This step is not applicable for Integrity systems Create a configuration file rtcconfig to specify the various thread conditions that you want the debugger to detect 190 HP UX Configuration Specific Information A NOTE The configuration file contains lines of the following form set thread check on off option on off option num And Or set frame count num And Or files lt name of the executable on which the thread checking is to be done gt For more information see Enabling and Disabling Advanced Thread Debugging Features page 183 4 Set the environment variable BATCH_RTC to on as Set BATCH RTC on 14 11 Thread Debugging Support 191 5 Complete one of the following steps to preload the 1ibrtc runtime library e Set the target application to preload 1ibrtc by using the rtc option for
318. nion union tag or enum enum tad ptype expr ptype Print a description of the type of expression expr ptype differs from whatis by printing a 115 info types regexp info types info source info sources info functions 116 Examining the Symbol Table detailed description instead of just the name of the type For example for this variable declaration struct complex double real double imag v the two commands give this output gdb whatis v type struct complex gdb ptype v double real double imag As with whatis using ptype without an argument refers to the type of the last value in the value history Print a brief description of all types whose names match regexp or all types in your program if you supply no argument Each complete typename is matched as though it were a complete line thus i type value gives information on all types in your program whose names include the string value but i type value s gives information only on types whose complete name is value This command differs from pt ype in two ways first like whatis it does not print a detailed description second it lists all source files where a type is defined Show the name of the current source file that is the source file for the function containing the current point of execution and the language it was written in Print the names of all source files in your program for which there is d
319. nneays 150 14 8 2 Inline Debugging in Integrity Systems vsisesr anesthe teneiveneveteans 151 14 8 2 1 Debugging Inline Functions in Integrity Systems 0 ceeee eee eee 152 14 9 Debugging Macros iinne eee E Ete aE tegncde tan E E E Ea 153 14 9 1 Viewing and Evaluating Macro Definitions s sssesesssesssessrssesrsersreseesserssesees 153 14 9 1 1 Compiler Options to Enable Macro Debugging eseseessrsesssesssrssreseesse 154 14 9 2 Examples for Macro Debus cine szianaispucseineaasten asc pdionduaae kcbaadic 155 14 10 Debugging Memory Problems cissvcccosyeveccisoh cuaiesnsisevadsavkatoassetoeasapindeesnitieeatandaeecoans 157 14 10 1 When to suspect a memory leak ssssensssseseesssseseessssetssssestesesseseensssensenseseees 158 14 10 2 Memory debugging testich Ons inde ccicsy i etuaugeiea enlaces 158 14 10 35 Memory Debugging Methodolopiesictscscticescsccteiscii dcrscueastinesitnveresatngaues 158 14 10 4 Debugging Memory in Interactive Mode ccceceececssecesseeeeeeseeeseeenseenes 159 14 10 4 1 Commands for interactive memory debugging ceccee eee eres 159 14 10 4 2 Example for interactive debugging SCSSION ccccscceseeseesseeseeeseeseenes 163 14 10 5 Debugging Memory in Batch Modes iissiscessccsaatcuvisvevecusestsdessavecdeveaviveuwbevedesiens 164 14 10 5 1 Setting Configuration Options for Batch Mode ccc cee eee eee eeeees 164 14 10 5 2 Environment variable setting for Batch mode debugg
320. nning on 11i v3 or later 14 10 10 3 info heap arena 0 1 2 blocks stacks Displays the memory profile report for block level and overall memory usage with stack trace where applicable This command is available only for applications running on 11i v3 or later 14 10 10 4 info module ADDRESS The info module command identifies load modules and determines whether it lies in the text or data region for a given address This command is available only for applications running on 11i v3 or later Syntax info module ADDRESS 14 10 10 5 info heap process The info heap process command enables the user to view a high level memory usage report of a process This command is available only for applications running on 11i v3 or later 14 10 10 6 Example for heap profiling This example shows how to use this feature on HP UX 11 x 1 If the linker version is earlier than B 11 19 link with opt langtools 1lib pa20_ 64 librtc s1 for PA 64 programs For a 32 bit program you must link with opt langtools lib librtc sl If the dynamic linker version is B 11 19 or later skip this step because WDB automatically loads the librtc s1 library 2 Turn on profiling with the set heap check on command gdb set heap check on 3 Set a breakpoint gdb b myfunction 14 10 Debugging Memory Problems 179 4 When the program is stopped at a breakpoint use the info heap command gdb info heap Analyzing heap done Actual Heap Usage
321. nning program For enabling automatic debugging of shared libraries you must install the kernel patches PHKL_38651 and PHKL_38778 To avoid changing of the run time binding behavior of a program to BIND_ IMMEDIATE to perform command line call do the following e Use the linker option ea to export symbols from an object file e Install the linker patch PHSS 28870 for 11 0 or PHSS 28871 for 11i e Execute the following commands ec c file c cc file o Wl ea opt langtools lib end o s 14 35 Support for command line calls in a stripped executable 239 14 35 2 2 For 64 bit applications To perform command line calls in a stripped executable linked with end o you need to do the following e Inthe std link mode GDB supports this feature without any changes You must export the wdb_call_dummy symbol as shown in the next line e Inthe compat link mode execute the following command cc DD64 g file c Wl ee wdb call dummy s 14 35 3 Support for debugging stripped binaries HP WDB provides limited support for debugging stripped binaries 14 35 3 1 Printing of locals and globals in a stripped module GDB will not be able to print the locals and statics declared in a module which has been stripped GDB will be able to print the exported symbols since exported symbols are not stripped with strip command they stay in dynsym GDB will be able to access the globals or locals defined in other unstripped shared librar
322. nother terminal NOTE If the underlying GDB terminates abnormally when you are using Visual Interface for WDB do not close the Visual Interface for WDB window Wait for a minute or two Visual Interface for WDB captures the stack trace and the debugging session details and sends you an email You can then forward this to HP when you report the problem This is helpful to HP in reconstructing the crash scenario 14 31 1 Starting and stopping Visual Interface for WDB You can use Visual Interface for WDB in either of two modes e X window based graphical interface Supports mouse and keyboard commands e Terminal interface Supports keyboard commands only Visual Interface for WDB accepts the same command line arguments as GDB so you can add options to the startup command See the man page for GDB for the list of arguments e To start Visual Interface for WDB in graphical mode with mouse support run Visual Interface for WDB with the command opt langtools bin vdb e To start Visual Interface for WDB in terminal user interface mode run Visual Interface for WDB with the command opt langtools bin vdb tui e To stop Visual Interface for WDB type quit on the WDB command line 14 31 Visual Interface for WDB 233 wdb quit 14 31 2 Navigating the Visual Interface for WDB display The Visual Interface for WDB window consists of two areas e Source pane at the top e Debugger pane at the bottom You can use the arrow and paginatio
323. ns expect different patterns of arguments 120 Altering Execution or of local variables For this reason the j ump command requests confirmation if the specified line is not in the function currently executing However even bizarre results are predictable if you are well acquainted with the machine language code of your program jump address Resume execution at the instruction at address address On many systems you can get much the same effect as the j ump command by storing anew value into the register pc This does not start the execution of your program at the specified address instead only changes the program counter For example set Spc 0x485 makes the next cont inue command or stepping command execute at address 0x485 rather than at the address where your program stopped See Continuing and stepping page 64 The most common occasion to use the j ump command is to back up perhaps with more breakpoints set over a portion of a program that has already executed in order to examine its execution in more detail 11 3 Giving your program a signal You can use the following command to send signals to your program signal signal Resume execution where your program stopped but immediately give it the signal signal signal canbe the name or the number of a signal For example on many systems signal 2 and signal SIGINT are both ways of sending an interrupt signal Alternatively if signal is zero continue exec
324. nsnesndets devanesvutienetenndedtzovuntesanestnebnnten y 290 19 UsingxGDB under gnu Emacs 22ers eek te cette n EEEE et ca REE hed eee EEE Meher anata 293 20 GDB Annotations e a a teanteveduvedes aa a eagtedecunssen a E aea 297 2031 Wheat anann aI ra AE E E EEA OA N ONEA IAEE 297 20 2 The SERVER PUCK earrais eeit ei Ere T EAE E E a RTEA RNE aguas canes eet ene Eak 297 AS VEE asi EET E N a E E ATE A Dat woke dah ee aed eR detdses Cove Seeds 298 DAE RAIN EAE A A EA E ONTA S A E E NAE 299 20 5 DIS play Sarisin sna ei e eE E E E T E E E E EATE EE 301 20 6 Annotation fot GDB ii putivecs lt sepvencessesspcedsseccesshueessatastn dies vavepecssnuikerthcaraeasaremeedgnenieceans 301 Table of Contents 11 DOPE TLOLS it stress fe ee Sadat esas aaNet a Te A Te hE ees AE a A eC 302 20 8 Information on Direak POM ts 4i i5 cc coisa ten cccest te i toeasedncvencpuekpoprasu eae doueomnbeeniers scent beeen 302 20 9 Triv alid ation NOU CES 2 heist coeds sss coeedots devas se elbegets A A a AS ees AES 303 20 10 Runa the LOS aI istenes sena i iira evens E EE EAA AENA NE E nes 303 QO Displaying SO rCE trehet iret aeta a ae a aiia 304 20 12 Annotations We Might Want in the Future sessesssessessessseissisersserssissreseesseesreseesse 305 Di he CpDB Mi Internacer nino a a a nah E E O N A N AA E A E 307 2d GDB PMT A Oman Syntax ke eneas eres ede eae EEE EEE E EE aiee iaa 307 lols GDB MI Dap t syntax nesir r a a E E a RRE 307 2112 GDB MT QUtP ESyNtAX siii
325. nt info unwind command prints the unwind information for the regions unwinded at the given address expression Usage maint info unwind exp where exp is an address expression For example gdb maint info unwind pc modsched 0x4000930 0x4000a20 end_prologue 0x4000970 Info block version 0x0 flags 0x0 length 4 4 16 0x40172b20 Oc Rlprologue rlen 12 0x40172b21 e8 P7preds_ when t 11 0x40172b23 b1 P3preds_ gr gr 41 0x40172b25 ea P71c when t 7 14 13 Debugging multiple processes programs with fork and vfork calls 195 0x40172b27 b2 P3lc_gr gr 40 0x40172b29 61 R3body rlen 33 0x40172b2b 81 Bllabel_ state label 1 0x40172b2c c0 B2epilogue t 44 0x40172b2e 00 Rlprologue rlen 0 0x40172b2f 00 Rlprologue rlen 0 14 13 4 Printing CFM and PFS registers On Integrity systems HP WDB prints Current Frame Marker CFM and Previous Frame State PFS ar64 registers in two different formats e raw values e special formats identifying the size of rotating registers frame and locals For example ar64 0xc00000000000050c sor 0 sol 10 sof 12 cfm 0x800000000000450a sor 1 sol 10 sof 10 14 14 Command to Search for a Pattern in the Memory Address Space The HP WDB find command searches for a pattern in the given memory address range for both live and corefile debugging Following is the syntax for the find command find size char max count start address end address exprl expr2
326. nted automatically but is not forgotten It may be enabled again later enable display dnums Enable display of item numbers dnums It becomes effective once again in auto display of its expression until you specify otherwise display Display the current values of the expressions on the list just as is done when your program stops info display Print the list of expressions previously set up to display automatically each one with its item number but without showing the values This includes disabled expressions which are marked as such It also includes expressions which would not be displayed right now because they refer to automatic variables not currently available If a display expression refers to local variables then it does not make sense outside the lexical context for which it was set up Such an expression is disabled when execution enters a context where one of its variables is not defined For example if you give the command display last_char while inside a function with an argument last_char GDB displays this argument while your program continues to stop inside that function When it stops elsewhere where there is no variable last_char the display is disabled automatically The next time your program stops where last_char is meaningful you can enable the display expression again 8 7 Print settings 90 GDB provides the following ways to control how arrays structures and symbols are printed These settings
327. nts collectively on all instances of inline functions and enable inline debugging enter either of the following commands 152 HP UX Configuration Specific Information gdb set inline debug inline _bp all or gdb inline inline bp all e To set and modify individual breakpoints on specific instances of inline functions and enable inline debugging enter either of the following commands be fore debugging the application gdb set inline debug inline _bp individual or gdb inline inline bp individual e To disable inline debugging enter either of the following commands be fore debugging the application gdb set inline debug off or gdb inline off 3 You can use the following commands for debugging inline functions in Integrity systems step next list backtrace frame lt n gt info locals info args breakpoint The following commands are not available for debugging inline functions in Integrity systems info frame disassembly 14 9 Debugging Macros HP WDB 5 7 and later versions of the debugger enable you to display and evaluate macro definitions for programs running on Integrity systems This feature is available only for compiler versions A 06 15 and later 14 9 1 Viewing and Evaluating Macro Definitions HP WDB 5 7 and later versions of the debugger provide the following support for de bugging macros e Displaying Macro Definitions Displaying Macro Definitions HP WDB provides the following comm
328. nvironment variable and the stty rows and stty cols settings If this is not correct you can override it with the set height and set width commands setheight 1pp show These set commands specify a screen height of 1pp lines and height se set width a screen width of cp1 characters The associated show cpl show width commands display the current settings If you specify a height of zero lines GDB does not pause during output no matter how long the output is This is useful if output is to a file or to an editor buffer Likewise you can specify set width 0 to prevent GDB from wrapping its output 17 5 Supported Number Formats You can always enter numbers in octal decimal or hexadecimal in GDB by the usual conventions octal numbers begin with 0 decimal numbers end with and hexadecimal numbers begin with 0x Numbers that begin with none of these are by default entered in base 10 likewise the default display for numbers when no particular format is specified is base 10 You can change the default base for both input and output with the set radix command set input radix base Set the default base for numeric input Supported choices for base are decimal 8 10 or 16 base must itself be specified either unambiguously or using the current default radix for example any of set radix 012 set radix 10 17 4 Setting the GDB Screen Size 283 set radix Oxa sets the base to decimal On the other hand set radix 10 leaves th
329. o procedures si step by instruction S S with xdb n ni Step over ni step over by instruction S number S number with xdb n Step over by number statements or instructions ni step over by instruction number ninumber 16 2 Overall breakpoint commands The following table lists the XDB and equivalent WDB commands for setting additional breakpoints Table 16 8 Overall breakpoint commands XDB Command WDB Equivalent Meaning O f lb with xdb ib List breakpoints No equivalent Toggle overall breakpoint state 16 2 1 Auxiliary breakpoint commands The following table lists the XDB and equivalent WDB auxiliary breakpoint related commands 260 XDB to WDB Transition Guide Table 16 9 Auxillary breakpoint commands XDB Command WDB Equivalent Meaning any_string p any string Print any string if expr cmds cmds if expr cmds else cmds Conditionally execute cmds end Q Q with xdb silent must Quiet breakpoints be first command in a commands list 16 2 2 Breakpoint creation commands The GDB equivalent of the count and cmds arguments is to use the commandsbnum command to set an ignore count and or to specify commands to be executed for that breakpoint For C programs you can use the regular expression breakpoint command rbreak to set breakpoints on all the member functions of a class or on overloaded functions outside a class The following table lists
330. o break witha breakpoint number n as argument lists only that breakpoint The convenience variable _ and the default examining address for the x command are set to the address of the last breakpoint listed see Examining memory page 87 info break displays a count of the number of times the breakpoint has been hit This is especially useful in conjunction with the ignore command You can ignore a large number of breakpoint hits look at the breakpoint info to see how many times the breakpoint was hit and then run again ignoring one less than that number This will get you quickly to the last hit of that breakpoint GDB allows you to set any number of breakpoints at the same place in your program There is nothing silly or meaningless about this When the breakpoints are conditional this is even useful see Break conditions page 59 5 1 Breakpoints 55 GDB itself sometimes sets breakpoints in your program for special purposes such as proper handling of longjmp in C programs These internal breakpoints are assigned negative numbers starting with 1 info breakpoints does not display them You can see these breakpoints with the GDB maintenance command maint info breakpoints maint info breakpoints Using the same format as info breakpoints display both the breakpoints you have set explicitly and those GDB is using for internal purposes Internal breakpoints are shown with negative breakpoint numbers The
331. odules The first instruction in each block associated with the executed branch is displayed This feature is supported only for compiler versions A 06 15 and later HP WDB supports the following commands to print the execution path entries in the current frame or in the current thread e info exec path start_index end_index aliased to info ep Lists all the local execution path entries in the current frame The start_index and end_index indicate the range of table indexes execution path entries that must be displayed If end_index is not specified the debugger displays the complete table of execution path entries starting from start_index If start_index and end_index are not specified the complete table of execution path entries is displayed 14 16 Printing the Execution Path Entries for the Current Frame or Thread 203 For example gdb i ep 4 10 e info exec path summary Prints the summary information about all the local execution path entries in the current frame This command displays the total number of branches for the frame the number of branches executed in this frame in the last iteration and the last executed branch number e info global exec path start index end index aliased to info gep Lists all the global execution path entries for the current thread The start_index and end_index indicate the range of table indexes execution path entries that must be displayed If end_index
332. of Memory Debugging Commands in Interactive Mode and Batch Mod ne eaa E E E A TE a E EE OESE rE AESSR 176 1410 10 Plea pO I Be sseni eeen ai S E aS 178 14 10 10 1 Commands for heap promi cascostroceicee ae waensstanceeaaeeosbustvcuntcsuietewnpstpnee 178 T410 102inforh ap arena orereta EE aE e E E AR EEE R 179 14 10 10 3 info heap arena 0 1 2 blocks stacks ee 179 14104 into modure ADDRESS sla wisn eaa nani accumiahinodsh 179 14 10 10 5 4n 6 heap PVOCESS itl iain aia iWin tes banter aieaseeaeee 179 14 10 10 6 Example for heap proce cscvicaeescreenietitavepintescneeitteeetntanndhaaaiyyatercs 179 14 10 11 Memory Checking Analysis for User Defined Memory Management ROUUMES Bove 8 seuss eee tebe ey E es ead avec a sapere A Oe ee a E A 180 14 10 12 Commands to track the change in data segment valUe c cccceseseereeeees 180 14 11 Thread Debug ein SOU pont waves svevonis cesustovesh pip teueuyl even iesmiseuevatiae demas euneranioerneniaes iy 181 14 11 1 Support for Enabling and Disabling Specific Threads cceeeeeeeeeees 181 14 11 2 Backtrace Support for Thread Debugging sssssssssesssrseseisessesressssessessestees 182 14 11 3 Advanced Thread Debugging Suppott cee cece ceee cess ceeeeeseeeseeenseenes 182 14 11 3 1 Pre requisites for Advanced Thread Debugging cee eee eee 183 14 11 3 2 Enabling and Disabling Advanced Thread Debugging Features 183 14 11 3 3 Commands to view information on pt
333. of files that the debugger knows were compiled with g 2 Make certain that the debugger can find the source file Type show dir to find the list of directories the debugger uses to search for source files and type set dir to change that path On HP UX the debug information does not contain the full path name to the source file only the relative path name that was recorded at compile time Consequently you may need several dir commands for a complex application with multiple source directories One way to do this is to place them ina gdbinit file placed in the directory used to debug the application A sample of the gdbinit file might look like the following dir home fred appx system dir home fred appx display dir home fred appx actor dir home fred appx actor sys When you compile the program with the obj debug option the debugger may nd the source files without using the dir command This happens because the debugger stores the full path name to the object files and searches for source files in the same directories 14 7 Fix and continue debugging Fix and continue enables you to see the result of changes you make to a program you are debugging without having to re compile and re link the entire program For example you can edit a function and use the ix command which automatically re compiles the code links it into a shared library and continues execution of the program without leaving the debugger With Fix and Con
334. ondition like break if is given however See Expressions page 83 condition bnum Remove the condition from breakpoint number bnum It becomes an ordinary unconditional breakpoint A special case of a breakpoint condition is to stop only when the breakpoint has been reached a certain number of times This is so useful that there is a special way to do it using the ignore count of the breakpoint Every breakpoint has an ignore count which is an integer Most of the time the ignore count is zero and therefore has no effect But if your program reaches a breakpoint whose ignore count is positive then Stopping and Continuing instead of stopping it just decrements the ignore count by one and continues As a result if the ignore count value is n the breakpoint does not stop the next n times your program reaches it ignore bnum count Set the ignore count of breakpoint number bnumto count The next count times the breakpoint is reached your program s execution does not stop other than to decrement the ignore count GDB takes no action To make the breakpoint stop the next time it is reached specify a count of zero When you use cont inue to resume execution of your program from a breakpoint you can specify an ignore count directly as an argument to continue rather than using ignore See Continuing and stepping page 64 If a breakpoint has a positive ignore count and a condition the condition is not checked
335. ooking for a program to run You can change the value of this variable for both GDB and your program using the path command On systems with memory mapped files an auxiliary file named filename syms may hold symbol table information for filename If so GDB maps in the symbol table from filename syms starting up more quickly See the descriptions of the file options mapped and readnow available on the command line and with the commands file symbol file or add symbol file described below for more information file with no argument makes GDB discard any information it has on both executable file and the symbol table Specify that the program to be run but not the symbol table is found in file name GDB searches the environment variable PATH if necessary to locate your program Omitting 12 1 Commands to specify files 125 symbol file filename symbol file filename readnow mapped file 126 GDB Files filename means to discard information on the executable file Read symbol table information from file filename PATH is searched when necessary Use the file command to get both symbol table and program to run from the same file symbol file with no argument clears out GDB information on the symbol table of your program The symbol file command causes GDB to forget the contents of its convenience variables the value history and all breakpoints and auto display expressions This is because th
336. opsis environment pwd Show the current working directory GDB command The corresponding GDB command is pwd Example gdb environment pwd Working directory kwikemart marge ezannoni flathead dev devo gdb done gdb 21 7 GDB MI program control Program termination As a result of execution the inferior program can run to completion if it does not encounter any breakpoints In this case the output will include an exit code if the program has exited exceptionally Examples Program exited normally gdb exec run running gdb x 55 stopped reason exited normally gdb Program exited exceptionally gdb exec run running gdb x 55 stopped reason exited exit code 01 gdb Another way the program can terminate is if it receives a signal such as SIGINT In this case GDB MI displays this gdb stopped reason exited signalled signal name SIGINT signal meaning Interrupt 330 The GDB MI Interface The exec abort command Synopsis exec abort Kill the inferior running program GDB command The corresponding GDB command is kill Example N A The exec arguments command Synopsis exec arguments args Set the inferior program arguments to be used in the next exec run GDB command The corresponding GDB command is set args Example Do not have one around The exec continue command Synopsis exec continue Asynchronous command Resumes t
337. ose levels are between the two 21 9 GDB MI Stack Manipulation Commands 343 arguments inclusive If the two arguments are equal it shows the single frame at the corresponding level GDB command The corresponding GDB commands are backt race and where Example Full stack backtrace gdb stack list frames done stack frame level 0 addr 0x0001076c func foo file recursive2 c line 11 frame level 1 addr 0x000107a4 func foo file recursive2 c line 14 frame level 2 addr 0x000107a4 func foo file recursive2 c line 14 frame level 3 addr 0x000107a4 func foo file recursive2 c line 14 frame level 4 addr 0x000107a4 func foo file recursive2 c line 14 frame level 5 addr 0x000107a4 func foo file recursive2 c line 14 frame level 6 addr 0x000107a4 func foo file recursive2 c line 14 frame level 7 addr 0x000107a4 func foo file recursive2 c line 14 frame level 8 addr 0x000107a4 func foo file recursive2 c line 14 frame level 9 addr 0x000107a4 func foo file recursive2 c line 14 frame level 10 addr 0x000107a4 func foo file recursive2 c line 14 frame level 11 addr 0x00010738 func main file recursive2 c line 4 gdb Show frames between low frame and high frame gdb stack list frames 3 5 done stack frame le
338. ot contain special U n MII characters such as nl and of course c string seven bit iso c string content nl CR CR LF 21 1 GDB MI Command Syntax 307 Notes e The CLI commands are still handled by the MI interpreter their output is described below e The token when present is passed back when the command finishes e Some MI commands accept optional arguments as part of the parameter list Each option is identified by a leading dash and may be followed by an optional argument parameter Options occur first in the parameter list and can be delimited from normal parameters using this is useful when some parameters begin with a dash Pragmatics e We want easy access to the existing CLI syntax for debugging e We want it to be easy to spot a MI operation 21 1 2 GDB MI Output syntax The output from GDB MI consists of zero or more out of band records followed optionally by a single result record This result record is for the most recent command The sequence of output records is terminated by gdb If an input command was prefixed with a token then the corresponding output for that command will also be prefixed by that same token output gt out of band record result record gdb nl result record token result class result nl out of band record async record stream record async record exec async output status async output notify async output exec asyn
339. ote 3 9 gdb p len _rquote 4 7 1 10 Setting Variable Values During a Session 22 That certainly looks wrong assuming len_1lquote and len_rquote are meant to be the lengths of lquote and rquote respectively We can set them to better values using the p command since it can print the value of any expression and that expression can include subroutine calls and assignments gdb p len_lquote strlen lquote gdb p len_rquote strlen rquote Is that enough to fix the problem of using the new quotes with the m4 built in defn We can allow m4 to continue executing with the c continue command and then try the example that caused trouble initially A Sample GDB Session gdb c Continuing define baz defn lt QUOTE gt f 00 lt UNQUOTE gt baz 0000 Success The new quotes now work just as well as the default ones The problem seems to have been just the two typos defining the wrong lengths We allow m4 to exit by giving it an EOF as input C d Program exited normally The message Program exited normally isfrom GDB it indicates m4 has finished executing We can end our GDB session with the GDB quit command gdb quit 1 10 Setting Variable Values During a Session 23 24 2 Getting In and Out of GDB This chapter discusses how to start GDB and exit out of it The essentials are e type gdb to start GDB e type quit or C d to exit 2 1 Invoking GDB Invoke GDB by running the program
340. otices e similarly info returns a list of candidates for invalidation notices 20 12 Annotations We Might Want in the Future 305 306 21 The GDB MI Interface Function and purpose GDB MT is a line based machine oriented text interface to GDB It is specifically intended to support the development of systems which use the debugger as just one small component of a larger system This chapter is a specification of the GDB MI interface It is written in the form of a reference manual Notation and terminology This chapter uses the following notation e separates two alternatives e something indicates that something is optional it may or may not be given e group means that group inside the parentheses may repeat zero or more times e group means that group inside the parentheses may repeat one or more times e string means a literal string Acknowledgments In alphabetic order Andrew Cagney Fernando Nasser Stan Shebs and Elena Zannoni 21 1 GDB MI Command Syntax 21 1 1 GDB MI Input syntax command cli command mi command cli command token cli command nl where cli commandis any existing GDB CLI command mi command token operation option parameter nl token any sequence of digits option parameter parameter parameter non blank sequence c string operation any of the operations described in this chapter non blank sequence anything provided it does n
341. ou will get Orange Green Blue Values that do not form the sum of any combination of the elements will be displayed as integers while the values that form the sum of any combination of the elements will be printed as unions 14 27 4 Support for debugging typedefs When you have a typedef class as a template parameter you can set a breakpoint on a member function by using the command break Class lt typedef_classB gt memfunc 14 27 5 Support for steplast command for C and C Typically if a function call has arguments that make further function calls executing a simple step command in GDB steps into the argument evaluation call HP WDB includes the steplast command which helps to step into a function and not into the calls for evaluating the arguments However the steplast command is not available on Integrity systems The following example illustrates how GDB behaves when you execute the steplast command gdb 16 foo bar gt bar will return 10 gdb steplast foo x 10 at foo c 4 4 int k 10 If the steplast command is not meaningful for the current line GDB displays the following error message 14 27 Support for output logging 225 Steplast is not meaningful for the current line For example gdb 4 int k 10 gdb sl gt alias to steplast command error Steplast is not meaningful for the current line To execute the steplast command in C compiled applications you must compile the applica
342. ou wish to debug a core file instead you must kill the subprocess in which the program is running 12 1 Commands to specify files 127 add symbol file filename address add symbol file filename address readnow mapped add symbol file filename address data_address bss_address add symbol file filename section address section 128 GDB Files To do this use the kill command see Killing the child process page 45 The add symbol file command reads additional symbol table information from the file filename You would use this command when filename has been dynamically loaded by some other means into the program that is running address should be the memory address at which the file has been loaded GDB cannot figure this out for itself You can specify up to three addresses in which case they are taken to be the addresses of the text data and bss segments respectively For complicated cases you can specify an arbitrary number of ssection address pairs to give an explicit section name and base address for that section You can specify any address as an expression The symbol table of the file filename is added to the symbol table originally read with the symbol file command You can use the add symbol file command any number of times the new symbol data thus read keeps adding to the old To discard all old symbol data instead use the symbol file command without any arguments add symbol file does no
343. ou can use the command info sources to find out which files these are If you use maint print psymbols instead the dump shows information about symbols that GDB only knows partially that is symbols defined in files that GDB has skimmed but not yet read completely Finally maint print msymbols dumps just the minimal symbol information required for each object file from which GDB has read some symbols See Commands to specify files page 125 fora discussion of how GDB reads symbols in the description of symbol file 11 Altering Execution Once you think you have found an error in your program you might want to find out for certain whether correcting the apparent error would lead to correct results in the rest of the run You can find the answer by experiment using the GDB features for altering execution of the program For example you can store new values into variables or memory locations give your program a signal restart it at a different address or even return prematurely from a function 11 1 Assignment to variables To alter the value of a variable evaluate an assignment expression See Expressions page 83 For example print x 4 stores the value 4 into the variable x and then prints the value of the assignment expression which is 4 See Chapter 9 page 101 for more information on operators in supported languages If you are not interested in seeing the value of the assignment use the se
344. ount count 1 1 gdb bt 0 main at address_error c 41 gdb quit The program is running Exit anyway y or n y 14 20 Instruction Level Stepping During instruction level stepping with nexti and stepi WDB prints the assembly instruction along with the next source line gdb stepi 0x101530 0 st4 r9 r34 1337 args argce argc It also prints DOC line information which includes actual line number and the column number when debugging a binary with g O gdb stepi 8 1 0x4000820 1 nop m 0x0 GDB cannot step into a function with no debug information GDB cannot do a next over a line when there is not debug information However the cont inue command works in such situations 14 21 Enhanced support for watchpoints and breakpoints 14 21 1 Deferred watchpoints When you try to set a watchpoint in an expression HP WDB places a deferred watch point if HP WDB cannot evaluate the expression The watchpoint is automatically enabled whenever the expression can be evaluated during the programs execution This is especially useful when placing the watchpoints on unallocated addresses 14 21 2 Hardware watchpoints HP WDB provides support for hardware watchpoints on HP UX 11 x 14 21 3 Hardware breakpoints The hbreak command sets hardware assisted breakpoints hbreak args The arguments args is same as that for the break command and the breakpoint is set in the same way However the breakpoint uses hardware assisted b
345. ount n is used again the other arguments default as for successive uses of x The addresses and contents printed by the x command are not saved in the value history because there is often too much of them and they would get in the way Instead GDB makes these values available for subsequent use in expressions as values of the convenience variables _ and __ After an x command the last address examined is Examining Data available for use in expressions in the convenience variable _ The contents of that address as examined are available in the convenience variable _ If the x command has a repeat count the address and contents saved are from the last memory unit printed this is not the same as the last address printed if several units were printed on the last line of output 8 6 Automatic display If you find that you want to print the value of an expression frequently to see how it changes you might want to add it to the automatic display list so that GDB prints its value each time your program stops Each expression added to the list is given a number to identify it to remove an expression from the list you specify that number The automatic display looks like this 2 foo 38 3 bar 5 struct hack 0x3804 This display shows item numbers expressions and their current values As with displays you request manually using x or print you can specify the output format you prefer in fact display decides whether to use
346. our program gnu Decode based on the GNU C compiler g encoding algorithm hp Decode based on the HP ANSI C aCC encoding algorithm lucid Decode based on the Lucid C compiler lcc encoding algorithm show demangle style set print object set print object on set print object off show print object set print static members set print static members on set print static members off show print static members set print vtbl set print vtbl on set print vtbl off show print vtbl 8 8 Value history Decode using the algorithm in the C Annotated Reference Manual arm WARNING This setting alone is not sufficient to allow debugging cfront generated executables GDB would require further enhancement to permit that If you omit style you will see a list of possible formats Display the encoding style currently in use for decoding C symbols When displaying a pointer to an object identify the actual derived type of the object rather than the declared type using the virtual function table Display only the declared type of objects without reference to the virtual function table This is the default setting Show whether actual or declared object types are displayed Print static members when displaying a C object The default is on Do not print static members when displaying a C object Show whether C static members are printed or not Pretty print C virtual fun
347. overview of range checking In some languages it is an error to exceed the bounds of a type this is enforced with run time checks Such range checking is meant to ensure program correctness by making sure computations do not overflow or indices on an array element access do not exceed the bounds of the array 104 Using GDB with Different Languages For expressions you use in GDB commands you can tell GDB to treat range errors in one of three ways ignore them always treat them as errors and abandon the expression or issue warnings but evaluate the expression anyway A range error can result from numerical overflow from exceeding an array index bound or when you type a constant that is not a member of any type Some languages however do not treat overflows as an error In many implementations of C mathematical overflow causes the result to wrap around to lower values for example if mis the largest integer value and s is the smallest then m 1 s This too is specific to individual languages and in some cases specific to individual compilers or machines Refer to See Supported languages page 105 for further details on specific languages GDB provides the following additional commands for controlling the range checker set check range auto Set range checking on or off based on the current working language See Supported languages page 105 for the default settings for each language set check range on
348. p format expr Note The count and size portions of formats are not allowed in the p print command They are allowed in the x command examine memory p expr format p format amp amp expr p class No equivalent p lang show language p format Use x format command to obtain initial value then use x with no argument to obtain value of next memory location To obtain value of previous memory location use x _ 1 pq expr set expr set var expr pq expr format No equivalent 274 XDB to WDB Transition Guide Table 16 26 M through P continued XDB Command Equivalent WDB Command pq class No equivalent pq format No equivalent 16 8 7 Q through S Table 16 27 Q through S XDB Command Equivalent WDB Command q q Q Q with xdb silent must be first command in a commands list r arguments r arguments R R with xdb r s s si s number s number si number S S with xdb n ni S number S number with xdb n number ninumber sa number No equivalent sa No equivalent sb number disable number sb disable sb shared library No equivalent sm sm with xdb set height 0 sr sr with xdb tui display sregs with tui ss file No equivalent 16 8 8 T Table 16 28 T XDB Command Equivalent WDB Command T depth T depth with xdb bt full depth 16 8 Alphabetical lists of XD
349. p Snatr32 1 0 000 gdb p Snatr33 2 0 000 gdb p natr39 3 0 000 14 23 3 Handling Decimal Floating Point Data types GDB supports decimal floating point values in command line call of functions that contain decimal floating point arguments and which return decimal floating point arguments gdb print funcl 1 2dd 14 23 4 Evaluating Decimal Floating Point data types HP WDB versions 5 9 and above enable you to evaluate the decimal floating point variable and displays the output Use the commonly used GDB commands for evaluating and displaying expressions such as print to evaluate the decimal floating point variable 214 HP UX Configuration Specific Information HP WDB supports e Evaluation of expressions with decimal floating point constants and variables e Setting or assignment of decimal floating point constant or variable e Arithmetic operations such as addition subtraction multiplication division and negation with decimal floating point constants or variables e Comparison operations such as gt gt lt lt with decimal floating point constants or variables e Conversion between data types during assignment arithmetic and comparison operations and while printing values in specified format Assignment of Decimal floating point value to variable gdb print lt variable gt lt dfp const gt lt dfp var gt lt dfp const gt decimal floating point constant lt dfp var gt deci
350. p rtcconfig e BATCH_RTC enables or disables batch memory leak detection e GDB_SERVER is used to override the default path from where the gdb executable is used to provide the information on memory leak By default opt langtools bin gdb is used to print the output This can be overridden by setting GDB_SERVER appropriately e RTC MALLOC CONFIG is used to override the default config and rtcconfig file settings This variable can be set as follows export RTC MALLOC CONFIG config_stringl config strings e The config_strings are separated by a semi colon The following config_strings options exist for RTC_MALLOC_CONFIG abort _on_bounds 01 abort _on bad free 01 abort _on_nomem 01 leak_logfile stderr filename 168 HP UX Configuration Specific Information Aborts execution when heap objects bounds check fail value is 1 and the environment variable RTC_NO_ ABORT is not set Aborts execution when free or realloc is trying to free a heap object which is not valid value is 1 and environment variable RTC_NO_ABORT is not set Aborts execution when out of memory if value is 1 and environment variable RTC_NO_ABORT is not set The log file for batch mode must be specified stderr error message goes to stderr filename error message goes to filename means output is appended to the file mem _logfile stderr filename heap_logfile stderr filename Specify config_strings for check m
351. pe show warranty for warranty support If the TERM environment variable is not set to hpterm start the debugger and set the terminal type for editing in WDB with this command ksh shell TERM hpterm gdb mysum 148 HP UX Configuration Specific Information The problem might be that there is no return for the num function You can correct this without leaving the debugger Set a break point at main gdb b main Breakpoint 1 at 0x23f8 file sum c line 11 Run the program gdb run Starting program tmp hmc mysum Breakpoint 1 main at sum c 11 11 int num 10 When the program stops at the break point use the edit command to make changes to the source file Because you are going to edit the current file you do not need to specify a source file name gdb edit The edit command opens a new terminal session using your environment variable settings for terminal and editor The debugger automatically loads the source file Make the necessary changes In this case add return total to the function named num Save the edited source file and exit the editor This saves the changes in the actual source file for the program Use the fix command to recompile the program to see the results of the changes gdb fix Compiling dev src sum c Linking Applying code changes to sum c Fix succeeded The ix command creates a new executable that includes the changes you made to the source file The debugger au
352. pport for assembly level debugging Support for automatic loading of debug information Debug information is automatically loaded from modules when an application is com piled with the obj debug option Support for debugging PA RISC programs on Itanium based systems You can debug PA RISC applications and core files on Itanium based systems When you start HP WDB if the debug target is a PA RISC binary program the debugger automatically loads PA RISC WDB The PA RISC version of HP WDB is provided as part of the HP UX operating system Support for debugging large core files gt 2GB HP WDB supports debugging of core files with sizes more than 2 GB Support co variant type HP WDB can step into a co variant function The compiler generated function called thunks which is used internally by the compiler to support co variant return type is not shown when you do a backtrace or switch from one frame to another frame Similarly using a finish or return command at a co variant callee function directly returns the control back to the caller of thunks New attach command line options and handling pid or p HP WDB accepts pidor p followed by a process ID to attach a running process to the debugger 142 HP UX Configuration Specific Information 2 NOTE HP WDB cannot be attached to a process that is traced by tools which use ttrace such as Caliper adb and tusc The debugger displays the following error message on attempting to atta
353. print or x depending on how elaborate your format specification is it uses x if you specify a unit size or one of the two formats i and s that are only supported by x otherwise it uses print display expr Add the expression expr to the list of expressions to display each time your program stops See Expressions page 83 display does not repeat if you press RET again after using it display fmt expr For fmt specifying only a display format and not a size or count add the expression expr to the auto display list but arrange to display it each time in the specified format fmt See Output formats page 86 display fmt addr For fmt i or s or including a unit size or a number of units add the expression addr as a memory address to be examined each time your program stops Examining means in effect doing x fmt addr See Examining memory page 87 For example display i pc can be helpful to view the machine instruction about to be executed each time execution stops pc is a common name for the program counter see Registers page 98 undisplay dnums delete Remove item numbers dnums from the list of display dnums expressions to display undisplay does not repeat if you press RET after using it Otherwise you would just get the error No display number i 8 6 Automatic display 89 disable display dnums Disable the display of item numbers dnums A disabled display item is not pri
354. r lib libsubs s1 GDB searches first for home debugger 1lib libsubs s1 and then for tmp lib libsubs s1 Ifneither of these exists then GDB searches the default system directories and finds usr lib libsubs sl In most cases GDB_SHLIB_ PATH allows more flexibility than GDB_SHLIB_ ROOT because it allows you to specify more than one path However there are some cases in which you may want to choose to use GDB_SHLIB_ROOT For example if you have more than one shared library with the same name but different path names you may want to use GDB_SHLIB_ ROOT because GDB searches for libraries based on the full path name Note that GDB_SHLIB_ PATH may not give you the results you expect because GDB searches for libraries that match only the name regardless of the path and always accepts the first library that matches the name 130 GDB Files For example if you want to use tmp usr lib libsubs sland tmp usr share lib libsubs s1l you can set GDB_SHLIB_ ROOT to tmp Now whenever GDB encounters a library with the name usr lib libsubs sland usr share 1lib libsubs s1 GDB looks at tmp usr lib libsubs s1 and tmp usr share lib libsubs s1 respectively 12 3 Errors reading symbol files While reading a symbol file GDB occasionally encounters problems such as symbol types it does not recognize or known bugs in compiler output By default GDB does not notify you of such problems since they are relatively common and primarily of inter
355. r set thread check command such as recursive relock num waiter stack util thread exit no join detach thread exit own mutex cv wait no mx cv multiple mxs mixed sched policy and unlock not own 14 1 Summary of HP Enhancements to GDB 137 e Serial debugging of a parent and child process e Support for Parallel Processing limited to pthread parallelism but not the compiler generated parallelism for example with directives e Implementation of ask mode for set follow fork mode e Support for setting breakpoints using shared library name e Support for core file commands packcore unpackcore getcore dumpcore and info rtti address e On PA RISC systems sanity check for core files dumped by hardware generated signals can be performed HP WDB can detect and warn the user about certain cases of corrupted core files e Inline support is on by default on Integrity systems On PA RISC the inline support is still off by default e For PA 64 bit applications WDB can step into shared library bind on reference calls This support is available for PA 32 bit as well e Interception of synchronous signals used by sigwait sigwaitinfo and sigtimedwait functions These signals are displayed by WDB just like asynchronous signals but are always passed to the debugger whether nopass is set or not e Support for debugging hardware watchpoints and shared libraries e For PA 64 bit applications WDB can step into shared library bind on ref
356. r specified value Example If the user specifies 60 bytes the debugger takes it as 48 bytes If the user specifies 65 the debugger considers 64 bytes set heap check footer size Sets the Footer guard for each block of the num of bytes allocated memory The default number of bytes for the footer is one byte if this option is not used 14 10 4 2 Example for interactive debugging session This example describes checking a program running on HP UX 11 x using linker version B 11 19 or later 1 2 Link the program with usr lib libc s1 instead of libc a Run the debugger and load the program gt gdb a out Turn on leak checking gdb set heap check leaks on Set one or more breakpoints in the code where you want to examine cumulative leaks gdb b myfunction Run the program in the debugger gdb run Use the info command to show list of memory leaks gdb info leaks Scanning for memory leaks done 2439 bytes leaked in 25 blocks No Total bytes Blocks Address Function 0 1234 1 0x40419710 foo 1 333 1 0x40410bf8 main 2 245 8 0x40410838 strdup 14 10 Debugging Memory Problems 163 The debugger assigns each leak a numeric identifier 7 To display a stack trace for a specific leak use the info leak command and specify the number from the list associated with a leak gdb info leak 2 245 bytes leaked in 8 blocks 10 05 of all bytes leaked These range in size from 26 to 36 bytes and
357. r to some variables with a trailing underscore See Fortran page 112 This version of the manual documents WDB implemented on HP 9000 or HP Integrity systems running Release 11 x of the HP UX operating system WDB can be used to debug code generated by the HP ANSI C HP ANSI aC and HP Fortran compilers as well as the GNU C and C compilers It does not support the debugging of Pascal Modula 2 or Chill programs Free Software GDB is free software protected by the GNU General Public License GPL The GPL gives you the freedom to copy or adapt a licensed program but every person getting a copy also gets with it the freedom to modify that copy which means that they must get access to the source code and the freedom to distribute further copies Typical software companies use copyrights to limit your freedoms the Free Software Foundation uses the GPL to preserve these freedoms Fundamentally the General Public License is a license which says that you have these freedoms and that you cannot take these freedoms away from anyone else Contributors to GDB Richard Stallman was the original author of GDB and of many other GNU programs Many others have contributed to its development This section attempts to credit major contributors One of the virtues of free software is that everyone is free to contribute to it with regret we cannot actually acknowledge everyone here The file ChangeLog in the GDB distribution approximates
358. r your program is executing within the function foo but you can only use or examine the variable b while your program is executing inside the block where b is declared However you can refer to a variable or function whose scope is a single source file even if the current execution point is not in this file But it is possible to have more than one such variable or function with the same name in different source files If that happens referring to that name has unpredictable effects If you wish you can specify a static variable in a particular function or file using the colon colon notation file variable function variable Here file or functionis the name of the context for the static variable In the case of file names you can use quotes to make sure GDB parses the file name as a single word For example to print a global value of x defined in f2 c gdb p f 2 c x Examining Data This use of is very rarely in conflict with the very similar use of the same notation in C GDB also supports use of the C scope resolution operator in GDB expressions A WARNING Occasionally a local variable may appear to have the wrong value at certain points in a function just after entry to a new scope and just before exit You may see this problem when you are stepping by machine instructions This is because on most machines it takes more than one instruction to set up a stack frame including local variable defin
359. rary from a path that is different from the default paths you must use the LD_PRELOAD environment variable OR e Instead of automatically preloading 1ibrtc and mapping the shared libraries you can explicitly preload the required librtc library after mapping the shared libraries private In the case of HP 9000 systems you must explicitly map the share libraries as private by using the dbg enable option for the chat r command as follows 188 HP UX Configuration Specific Information chatr dbg enable lt executable gt This step is not required on Integrity systems To explicitly preload the librtc runtime library and start the target application enter one of the following commands For 32 bit IPF applications iD_PRELOAD opt langtools lib hpux32 librtc so lt executable gt For 64 bit IPF applications iD_PRELOAD opt langtools lib hpux64 librtc so lt executable gt For 32 bit PA applications LD PRELOAD opt langtools lib librtc sl lt executable gt For 64 bit PA applications LD_PRELOAD opt langtools lib pa20_64 librtc sl lt executable gt If LD_PRELOAD and chatr rtc are used to preload the librtc runtime library the librtc runtime library is loaded from the path specified by LD PRELOAD 3 Complete one of the following steps e Attach the debugger to the required process and enable thread debugging as follows gdb thread p lt pid gt or gdb thread lt executable gt
360. rches it sooner You can use the string cdir to refer to the compilation directory if one is recorded and cwd to refer to the current working directory cwd is not the same as The former tracks the current working directory as it changes during your GDB session while the latter is immediately expanded to the current directory at the time you add an entry to the source path directory Reset the source path to empty again This requires confirmation from the user 7 3 Specifying source directories 79 show directories Print the source path and display the directories it contains If your source path is cluttered with directories that are no longer of interest GDB can end up detecting the wrong version of the source To correct this situation follow these steps 1 Use directory with no arguments to reset the source path to empty 2 Use directory with suitable arguments to reinstall the directories you want in the source path You can add all the directories in one command 7 4 Source and machine code 80 You can use the command info line to map source lines to program addresses and vice versa and the command disassemble to display a range of addresses as machine instructions When run under GNU Emacs mode the info line command causes the arrow to point to the line specified Also info line prints addresses in symbolic form as well as hex info line linespec Print the starting and ending addresses of the co
361. read debugging features can be enabled only if the set thread check on command is enabled The following advanced thread debugging options are available for the set thread check command recursive relock on off Thisset thread check recursive relock on off command checks if a thread has attempted to acquire a non recursive mutex that it currently holds Re locking a non recursive mutex results in a deadlock At run time the debugger keeps track of each mutex in the application and the thread that currently holds each mutex When a thread attempts to acquire a lock on a non recursive mutex the debugger checks if the thread currently holds the lock object for the mutex The debugger transfers the execution control to the user and prints a warning message when this condition is detected unlock not own on off The set thread check unlock not own on off command checks if a thread has attempted to unlock a mutex or a read write lock that it has not acquired The debugger transfers the execution control to the user and prints a warning message when this condition is detected mixed sched policy on off Theset thread check mixed sched policy on off command checks if a thread is waiting blocked on a mutex or a read write lock that is held by a thread with a different scheduling policy This is not an application error and does not always result in deadlock However it degrades the application performance The debugger transfers t
362. reakpoint registers There are only two hardware breakpoints that can be set on Integrity systems This is useful in ROM code debugging and shared library debugging for libraries including dla that are not loaded private The normal breakpoints are converted to a hardware breakpoint when WDB cannot set a normal breakpoint in the shared library 208 HP UX Configuration Specific Information 14 21 3 1 Setting breakpoints in unstripped shared library GDB will not be able to put breakpoints using symbolic names of the symbols not in export list or line numbers in the stripped modules GDB will be able to place breakpoints using symbol names in the unstripped shared libraries loaded into the stripped executable 14 21 4 Support for procedural breakpoints HP WDB enables you to set breakpoints at the beginning first executable line of every function that can be debugged In addition you can specify a set of commands to be performed when the breakpoint is reached These breakpoints work like procedural breakpoints in the xdb debugger The breakpoint commands are rbp and rdp e rbp Sets breakpoints at the first executable statement in all the functions that can be debugged including any shared libraries that are already loaded The rbp command sets breakpoints in all the functions which can be debugged in all the source files After you set these breakpoints you can manage them like any standard breakpoints You can delete them disable th
363. rformed within a statement Backtrace commands backtrace may be used to display the current nest of function calls including for calls that are inlined Note that even at 01 C methods that are defined within a class and Fortran arithmetic statement functions are implicitly inlinable and are inlined Other functions are not inlined regardless of the inline pragmas or keywords 14 29 1 2 02 03 04 ipo Stepping by line number st ep next and running to a breakpoint break moves the state of a program forward However the program execution does not necessarily stop at the given line You can set breakpoints break at the entry to a routine that is not inlined and examine the values of parameters when the program execution stops at the entry of a routine The local variables can be examined within a function However the values of the local variables may not be available at all code locations in the function Assignment of new values to formal parameters or local variables is NOT supported in code compiled with optimization above 01 Optimization of code results in the reordering of the instructions and the source line numbers Hence the value of the variable which is printed by the debugger may not correspond to the reported source code location The debugger may print the value of the variable at a source code location either before or after the reported source code location If the printed value is not current with respect to the
364. riables List all the global and static variable names GDB command info variables in GDB gdb_search in gdbtk Example N A The symbol locate command Synopsis symbol locate GDB command gdb_loc in gdbtk Example N A The symbol type command Synopsis symbol type variable Show type of variable GDB command The corresponding GDB command is ptype gdbtk has gdb_obj_variable 348 The GDB MI Interface Example N A 21 11 GDB MI Target Manipulation Commands The target attach command Synopsis target attach pid file Attach to a process pidor a file file outside of GDB GDB command The corresponding GDB command is attach Example N A The target compare sections command Synopsis target compare sections section Compare data of section section on target to the exec file Without the argument all sections are compared GDB command The GDB equivalent is compare sections Example N A The target detach command Synopsis target detach Disconnect from the remote target There is no output GDB command The corresponding GDB command is detach 21 11 GDB MI Target Manipulation Commands 349 Example gdb target detach done gdb The target download command Synopsis target download Loads the executable onto the remote target It prints out an update message every half second which includes the fields section The name of the
365. rn command does not resume execution it leaves the program stopped in the state that would exist if the function had just returned In contrast the finish command see Continuing and stepping page 64 resumes execution until the selected stack frame returns naturally 11 5 Calling program functions call expr Evaluate the expression expr without displaying void returned values You can use this variant of the print command if you want to execute a function from your program but without cluttering the output with void returned values If the result is not void it is printed and saved in the value history For the A29K a user controlled variable call_scratch_address specifies the location of a scratch area to be used when GDB calls a function in the target This is necessary because the usual method of putting the scratch area on the stack does not work in systems that have separate instruction and data spaces 11 6 Patching programs By default GDB opens the file containing the executable code of your program or the corefile as read only This prevents accidental alteration to machine code and it also prevents you from intentionally patching your program binary If you would like to be able to patch the binary you can specify that explicitly with the set write command For example you might want to turn on internal debugging flags or even to make emergency repairs set write on If you specify set write on GDB opens exec
366. rocesses started under the debugger or dynamically loaded after an attach are mapped private 14 22 6 Setting breakpoints in shared library Breakpoints can be set on functions in a shared library by specifying the library name with the function name gdb b libutil sl fun Breakpoint 1 at 0x79a86228 file simple c line 13 from CLO Components WDB build hppal 1 hp hpux11 00 gdb simple shared lib sl 14 22 7 Enhancement to the info shared Command HP WDB 6 0 and later versions provide the enhanced info shared command to display the global pointer gp values along with text start text end data start and data end values of the shared library Following is asample output of the info shared command with the gp values tstart tend dstart dend gp usr lib hpux32 dld so 0x2000000065858000 0x20000000658fb080 0x2000000065853000 0x2000000065857a38 0x2000000065855720 usr lib hpux32 libstd_v2 so 1 0x20000000656ab000 0x200000006584bfc0 0x200000006569d000 0x20000000656aac28 0x20000000656a6d78 14 23 Debugging support for Decimal Floating Point data type HP WDB versions 5 9 and above enable you to print and evaluate decimal floating point data types for programs running on the September 2008 release of HP UX 11i v3 Integrity systems This feature is available only for compiler versions A 06 20 and later The various features supported for decimal floating point data types are as follows e Printing Decimal Floating point data types Printing
367. rogram counter PC and address of gr32 in the backing store BSP This command enables you to view the stack trace when the stack is corrupted When using this command you must ensure that the SP PC and BSP values are valid The syntax for the backtrace _other_ thread command is as follows backtrace other thread SP PC BSP 14 11 3 Advanced Thread Debugging Support Advanced thread debugging support is available for multi threaded applications running on HP UX 11iv2 or HP UX 11iv3 HP WDB 5 5 and later versions provide advanced thread debugging features to display extended information on the state of pthread primitives such as mutexes read write locks and conditional variables HP WDB 5 6 and later versions provide advanced thread debugging options to detect the following thread related conditions e The thread attempts to acquire a non recursive mutex that it currently holds e The thread attempts to unlock a mutex or a read write lock that it has not ac quired e The thread waits blocked on a mutex or read write lock that is held by a thread with a different scheduling policy e Different threads non concurrently wait on the same condition variable but with different associated mutexes e The thread terminates execution without unlocking the associated mutexes or read write locks e The thread waits on a condition variable for which the associated mutex is not locked 182 HP UX Configuration Specific Informat
368. rors when your program is running GDB can check for conditions like the above if you wish Although GDB does not check the statements in your program it can check expressions entered directly into GDB for evaluation via the print command for example As with the working language GDB can also decide whether or not to check automatically based on your source language See Supported languages page 105 for the default settings of supported languages 9 3 1 An overview of type checking Some languages are strongly typed meaning that the arguments to operators and functions have to be of the correct type otherwise an error occurs These checks prevent type mismatch errors from causing run time problems For example 1 2 3 but 9 2 Displaying the language 103 error 1 2 3 The second example fails because the CARDINAL 1 is not type compatible with the REAL 2 3 For the expressions you use in GDB commands you can tell the GDB type checker to skip checking to treat any mismatches as errors and abandon the expression or to only issue warnings when type mismatches occur and evaluate the expression anyway When you choose the last of these GDB evaluates expressions like the second example above but also issues a warning Even if you turn type checking off there may be other reasons related to type that prevent GDB from evaluating an expression For instance GDB does not know how to add an int anda struct foo These particular
369. rowser to read the file tui htm1 which is usually installed in the directory opt langtools wdb doc on HP UX systems Do not use this option if you run GDB from Emacs see Using GDB under gnu Emacs page 293 xdb Run in XDB compatibility mode allowing the use of certain XDB commands For information see the file 1 GDB built with DJGPP tools for MS DOS MS Windows supports this mode of operation but the event loop is suspended when the debug target runs 2 1 Invoking GDB 29 interpreter interp write statistics version pid inline src_ nog xdb_trans html which is usually installed in the directory opt langtools wdb doc on HP UX systems Use the interpreter interp for interface with the controlling program or device This option is meant to be set by programs which communicate with GDB using it as a back end For example interpreter mi causes GDB to use the gdbmi interface see The GDB MI Interface page 307 Open the executable and core files for both reading and writing This is equivalent to the set write on command inside GDB see Patching programs page 122 This option causes GDB to print statistics about time and memory usage after it completes each command and returns to the prompt This option causes GDB to print its version number and no warranty blurb and exit This option causes GDB to attach to a running process This option causes the debugger to
370. rtual function tables See Print settings page 90 The vtbl commands do not work on programs compiled with the HP ANSI C compiler aCC Enable overload resolution for C expression evaluation The default is on For overloaded functions GDB evaluates the arguments and 9 4 Supported languages 111 set overload resolution off show overload resolution Overloaded symbolnames 9 4 2 Fortran searches for a function whose signature matches the argument types using the standard C conversion rules see C expressions page 109 for details If it cannot find a match it emits a message Disable overload resolution for C expression evaluation For overloaded functions that are not class member functions GDB chooses the first function of the specified name that it finds in the symbol table whether or not its arguments are of the correct type For overloaded functions that are class member functions GDB searches for a function whose signature exactly matches the argument types Display current overload resolution setting for C expression evaluation You can specify a particular definition of an overloaded symbol using the same notation that is used to declare such symbols in C type symbol types rather than just symbol You can also use the GDB command line word completion facilities to list the available choices or to finish the type list for you See Command completion page 33 for det
371. s 253 16 1 By function lists of XDB commands and HP WDB equivalents c ccceeeee 253 16 1 1 Invocation COMMANAS cccccccccceeeeccceesssceceeessccceeussceseusesceseueessesseesseueeeessseeeess 254 16 1 2 Window mode command snoeren a T AN S a 254 16 1 3 File viewing COMIN GINS se cents waived irainei ue eiai e aia aa eas ii 255 16 1 4 Source directory mapping COMMANDS ii ssecs poxssatevvis ross sets tonsevvecoeensviieusbnvereeuss 256 16 1 5 Data Viewing and modification COMMANAS cccc sec esse cess eeeeeeeeeeseeeeeeeees 256 16 1 6 Stack viewing command S isse i aa oe cece a ae iE e aa EET ah 258 16 1 7 Status viewing COMMA cenatensncesncanvtorbarienasneteunsedynanciaaterimanernegsedizuivedetsevnedys 259 16 1 8 Job control commands esssseseeeseesssseseeereeesssssssesteetssssssesereeeessssesrreeeesessessseee 259 16 2 Overall breakpoint commandsS sessessseesesseessersstseesserssessseseessesssereesseesresrersessesees 260 16 2 1 Auxiliary breakpoint commandSs ssssesssessrsessseissiesesseessessssresserssrsnesserssesees 260 16 2 2 Breakpoint creation commands s esessesssessrsessseississsseessensereesseesresresseessesees 261 16 2 3 Breakpoint status COMMMANAS a cel evitesss tcxesyoreucdes vsti calosdsituam biker eile mene 262 16 2 4 All procedures breakpoint COMMANAG cccceeeeeeeeecseceseceeeeeeeeeeseeenseenes 263 16 2 5 Global breakpoint COMUMMAINGS x csv0 5 yaxncchas exeresoveznaservedeagead
372. s another enabled breakpoint at the same address In that case GDB might see the other breakpoint first and stop your program without checking the condition of this one Note that breakpoint commands are usually more convenient and flexible than break conditions for the purpose of performing side effects when a breakpoint is reached see Breakpoint command lists page 61 Break conditions can be specified when a breakpoint is set by using if in the arguments to the break command See Setting breakpoints page 52 They can also be changed at any time with the condition command You can also use the if keyword with the wat ch command The catch command does not recognize the if keyword conditionis the only way to impose a further condition on a catchpoint condition bnum expression Specify expression as the break condition for breakpoint watchpoint or catchpoint number bnum After you set a condition breakpoint bnum stops your program only if the value of expression is true nonzero in C When you use condition GDB checks expression immediately for syntactic correctness and to determine whether symbols in it have referents in the context of your breakpoint If expression uses symbols not referenced in the context of the breakpoint GDB prints an error message No symbol foo in current context GDB does not actually evaluate expression at the time the condition command or a command that sets a breakpoint with a c
373. s condition is detected 14 11 3 3 Commands to view information on pthread primitives WDB 5 5 and later versions of the debugger display extended information on pthread primitives for multi threaded applications running on HP UX 11i v2 or 11i v3 This feature is available only if the set thread check on off command is enabled The following commands enable you to view extended information on threads mutexes read write locks and conditional variables in multi threaded applications info thread thread id The info thread thread id command displays a list of known threads If a thread id is provided the command displays extended information on the specified thread info mutex mutex id The info mutex mutex id command displays a list of known mutexes If a mutex id is provided the command displays extended information on the specified mutex info condvar condvar id Theinfo condvar condvar id command displays a list of known condition variables If condvar id is provided the command displays extended information on the specified condition variable info rwlock rwlock id The info rwlock rwlock id command displays a list of known read write locks If rwlock id is provided the command displays extended information on the specified read write lock 14 11 4 Debugging Threads Interactively After Attaching to a Process HP WDB provides support to attach a running process to the debugger To use thread debugging commands af
374. s on check _free on files executable name output dir tmp results 3 Set the following environment variables as follows export BATCH _RTC on 4 Complete one of the following steps Preload the librtc runtime library as follows PRELOAD opt langtools 1lib hpux32 librtc so lt executable gt lt arguments if any gt OR Preload the librtc runtime library as follows chatr rtc enable lt executable gt e Example from Integrity Systems Example 2 1 Compile the source files 170 HP UX Configuration Specific Information 2 The rtcconfig file should contain entries such as the following check _heap on check _leaks on check _free on files execl exec2 exec3 output dir tmp results 3 Set the following environment variables as follows export BATCH _RTC on 4 Complete one of the following steps Use the rtc option for the chatr command on each of the required executable files that must be instrumented as follows chatr rtc enable execl exec2 exec3 OR Preload the librtc library as follows export LD PRELOAD opt langtools lib hpux32 librtc so 5 Run the program as follows execl Suppose exec1 eventually spawns exec2 exec3 exec4 exec5 only execl exec2 exec3 will be instrumented based on the settings in the rtcconfig file 14 10 6 Debugging Memory Interactively After Attaching to a Running Process HP WDB accepts pid or p followed by a process ID to attach a running process to the d
375. s step You can then examine and change variables set new breakpoints or remove old ones and then continue execution Usually the messages shown by GDB provide information on the status of your program but you can also explicitly request this information at any time info program Display information about the status of your program whether it is running or not what process it is and why it stopped 5 1 Breakpoints A breakpoint makes your program stop whenever a certain point in the program is reached For each breakpoint you can add conditions to control in finer detail whether your program stops You can set breakpoints with the break command and its variants see Setting breakpoints page 52 You can stop your program by line number function name or an address in the program You can arrange to have values from your program displayed automatically whenever GDB stops at a breakpoint See Automatic display page 89 In HP UX SunOS 4 x SVR4 and Alpha OSF 1 configurations you can set breakpoints in shared libraries before the executable is run See Debugging support for shared libraries page 210 A catchpoint is another special breakpoint that stops your program when a certain kind of event occurs such as the throwing of a C exception or the loading of a library As with watchpoints you use a different command to set a catchpoint see Setting catchpoints page 56 but apart from that you can manag
376. s to a running process one that was started outside GDB info files shows your active targets The command takes as argument a process ID The usual way to find out the process id of a Unix process is with the ps utility or with the jobs 1 shell command attach does not repeat if you press RET a second time after executing the command 44 Running Programs Under GDB A NOTE e Touseattach your program must be running in an environment which supports processes for example attach does not work for programs on bare board targets that lack an operating system e You must also have permission to send the process a signal e When you use attach the debugger finds the program running in the process first by looking in the current working directory then if the program is not found by using the source file search path see Specifying source directories page 79 You can also use the file command to load the program See Commands to specify files page 125 e GDB stops the process being attached for debugging You can examine and modify an attached process with the GDB commands that are available when you start processes with run You can insert breakpoints you can step and continue you can modify storage See Breakpoints page 51 If you want the process to continue running you can use the continue command after attaching GDB to the process detach When you have finished debugging the attached process you
377. sage Errors Using HP WDB whitepaper at the HP WDB Documentation webpage at http www hp com go wdb 14 10 1 When to suspect a memory leak You should suspect a memory leak in the code when you notice that the system is running out of swap space or running slower or both Applications or non kernel code including daemons that have memory leaks can eventually use up all swap space You can run top 1 to verify whether the process data space SIZE RES is growing more than you expect If the system is running out of swap space programs will fail with out of memory ENOMEM errors or SIGBUS signals In addition the system might run slower and slower until it comes to a stop all processes requiring swap to continue running will wait for it indefinitely GDB allows you to catch out of memory conditions through runtime memory checking Use the command catch nomem to detect out of memory conditions GDB will stop whenever malloc returns NULL and allows you to look at the current context 14 10 2 Memory debugging restrictions Programs with these attributes are not supported e CMA or DCE threaded programs on 11 x 32 bit and 64 bit e Memory checking features These features work only in programs that directly or indirectly call malloc realloc free mmap or munmap from the standard C library libc sl e Programs that link the archive version of the standard C library libc a or the core library libcl a on HP UX 11 x A NOTE Linker w
378. se to a program call of fork or vfork A call to fork or vfork creates a new process The mode can be parent The original process is debugged after a fork The child process runs unimpeded This is the default child The new process is debugged after a fork The parent process runs unimpeded show follow fork mode Display the current debugger response to a fork or vfork call If you ask to debug a child process and a vfork is followed by an exec GDB executes the new target up to the first breakpoint in the new target If you have a breakpoint set on main in your original program the breakpoint will also be set on the child process s main When a child process is spawned by vfork you cannot debug the child or parent until an exec call completes If you issue a run command to GDB after an exec call executes the new target restarts To restart the parent process use the file command with the parent executable name as its argument You can use the catch command to make GDB stop whenever a fork vfork or exec call is made See Setting catchpoints page 56 50 Running Programs Under GDB 5 Stopping and Continuing The principal purpose of a debugger is to let you stop your program before it terminates abnormally or runs into trouble so that you can investigate and determine the reason Inside GDB your program can stop for several reasons such as a signal a breakpoint or reaching a new line after a GDB command such a
379. section section sent The size of what has been sent so far for that section section size The size of the section total sent The total size of what was sent so far the current and the previous sections total size The size of the overall executable to download Each message is sent as status record see GDB MI Output syntax page 308 In addition it prints the name and size of the sections as they are downloaded These messages include the following fields section The name of the section section size The size of the section total size The size of the overall executable to download At the end a summary is printed GDB command The corresponding GDB command is load Example E NOTE Each status message appears on a single line Here the messages have been broken down so that they can fit onto a page gdb target download download section text section size 6668 total size 9880 download section text section sent 512 section size 6668 total sent 512 total size 9880 download section text section sent 1024 section size 6668 total sent 1024 total size 9880 350 The GDB MI Interface download section text section sent 1536 section size 6668 total sent 1536 total size 9880 download section text section sent 2048 section size 6668 total sent 2048 total size 9880 download section text section sent
380. ses Such aeea weed enya tals EE RE eae AEE EE ne ads a 241 15 The HP UX Terminal User Interface cccccccecccccccccececececececeseseeeceseseseeeeeeeeeseeeeeeeeeeeeeaeaeeeeeeeneas 243 A OCA CE Ee TUL sien bie otis tcp on aeiee eaae AE EE EE tas EEEE EEAS AEE DEEE tang 243 15 2 Automatically running a program at startup eesesssessessesssessrsssereessrsersrersrrssesees 244 T5 Screen Layouts reinen eena era Ea NEET e EE A nocd es EAE Ee E EEEE ENA 244 1531 S0Uurce paneres iret ea EE A a S A E E T E N ENSE 245 153 2 Dis ssembly paheni isan a n e a ea iee aean iea OES OE ERTE CNEA 245 15 3 9 So rc Disassemibly pana inre esiratas i acetals 246 15 3 4 Disassembly Register pane sssessessesessssesesssesressssttstssestesessesrensssensensestees 246 153 5 S0 rc Register pane neiaie rer Deka dd dt iene neers 247 T5 4 Cycling through the panes cecil iini i A E E a A s 248 15 5 Changing Pane LOCUS sarsies enirere er uie aaa E EEA EERE ves A EERE vieis 248 15 6 Scrolliiig panes ei ian ae ir a ies ee E E EEE ne a a aa 250 15 7 Changing the register CIS PLAY ssi wantensdiecsseiertoure rhvanadsneesesytasedtuesnmucnbernpsuavonmadetanenatys 250 15 8 Ch nging tne pane Sizemore erra aera E ra E Aa E E ASE een 251 15 9 Refreshing and updating the windoW sessesssssssssessserssisssserssresrereessersesresserssesees 252 16 XDB to WDB Transition Guide ccccccccccccceseecececcccsseeeuensecccccesseeeuenseseccscssuuaueasnescscsseuaaenensees
381. set Set range checking on or off overriding the default check range off setting for the current working language A warning is issued if the setting does not match the default language If a range error occurs and range checking is on then a message is printed and evaluation of the expression is aborted set check range warn Output messages when the GDB range checker detects a range error but attempt to evaluate the expression anyway Evaluating the expression may still be impossible for other reasons such as accessing memory that the process does not own a typical example from many Unix systems show range Show the current setting of the range checker and whether or not it is being set automatically by GDB 9 4 Supported languages GDB supports C C and Fortran Refer to for specific information about Fortran Some GDB features may be used in expressions regardless of the language you use the GDB and operators and the t ype addr construct see Expressions page 83 can be used with the constructs of any supported language The following section discusses GDB support for each source language These sections are not meant to be language tutorials or references but serve only as a reference guide to what the GDB expression parser accepts and what input and output formats should look like for different languages 9 4 Supported languages 105 9 4 1 Cand C Since C and C are so closely related many features
382. set environment andunset environment to change parts of the environment that affect your program See Program Environment page 41 Your program inherits its working directory from GDB You can set the GDB working directory with the cd command in GDB See Working directory page 43 Your program as default uses the same device for standard input and standard output as GDB is using You can redirect input and output in the run command line or you can use the tty command to set a different device for your program See Program Input and Output page 43 A WARNING You can redirect input and output but you cannot use pipes to pass the output of the program you are debugging to another program if you attempt this GDB is likely to wind up debugging the wrong program 2 NOTE A e When you issue the run command your program begins to execute immediately See Chapter 5 page 51 for discussion of how to arrange for your program to stop Once your program has stopped you may call functions in your program using the print or call commands See Chapter 8 page 83 e Ifthe modification time of your symbol file has changed since the last time GDB read its symbols GDB discards its symbol table and reads it again When it does this GDB tries to retain your current breakpoints 4 3 Arguments To Your Program The arguments to your program can be specified by the arguments of the run command On HP UX the
383. signal The syntax of this annotation is just like signalled but GDB is just saying that the program received the signal not that it was terminated with it Z Zbreakpoint number The program hit breakpoint number number pP prog pP Z Zwatchpoint number The program hit watchpoint number number 20 11 Displaying source The following annotation is used instead of displaying source code Z Zsource filename line character middle addr where filename is an absolute file name indicating which source file 1 ine is the line number within that file where 1 is the first line in the file character is the character position within the file where 0 is the first character in the file for most debug formats this will necessarily point to the beginning of a line middle is middle if addr is in the middle of the line or beg if addr is at the beginning of the line and addr is the address in the target program associated with the source which is being displayed addr is in the form 0x followed by one or more lowercase hex digits note that this does not depend on the language 304 GDB Annotations 20 12 Annotations We Might Want in the Future e target invalid the target might have changed registers heap contents or execution status For performance we might eventually want to hit registers invalidand all registers invalid with greater precision e systematic annotation for set show parameters including invalidation n
384. signment The value of an assignment expression is the value assigned Defined on scalar types op Used in an expression of the form a op b and translated to a a op b op and have the same precedence op is any one of the operators amp lt lt gt gt The ternary operator a b c can be thought of as if a then b else c a should be of an integral type Logical OR Defined on integral types amp amp Logical AND Defined on integral types Bitwise OR Defined on integral types Bitwise exclusive OR Defined on integral types amp Bitwise AND Defined on integral types 106 Using GDB with Different Languages lt lt gt lt By gt lt lt gt gt Equality and inequality Defined on scalar types The value of these expressions is 0 for false and non zero for true Less than greater than less than or equal greater than or equal Defined on scalar types The value of these expressions is 0 for false and non zero for true left shift and right shift Defined on integral types The GDB artificial array operator see Expressions page 83 Addition and subtraction Defined on integral types floating point types and pointer types Multiplication division and modulus Multiplication and division are defined on integral and floating point types Modulus is defined on integral types Increment and decrement When appearing before a variable the operat
385. sion information for GDB Used mostly in testing GDB command The corresponding GDB command is show version Example gdb gdb version GNU gdb 5 2 1 Copyright 2000 Free Software Foundation Inc GDB is free software covered by the GNU General Public License and you are welcome to change it and or distribute copies of it under certain conditions Type show copying to see the conditions There is absolutely no warranty for GDB Type show warranty for details This GDB was configured as host sparc sun solaris2 5 1 target ppc eabi done gdb 21 9 GDB MI Stack Manipulation Commands The stack info frame command Synopsis stack info frame Get info on the current frame GDB command The corresponding GDB command is info frame or frame without arguments Example N A The stack info depth command Synopsis stack info depth max depth Return the depth of the stack If the integer argument max depth is specified do not count beyond max depth frames GDB command There is no equivalent GDB command 21 9 GDB MI Stack Manipulation Commands 341 Example For a stack with frame levels 0 through 11 gdb stack info depth done depth 12 gdb stack info depth 4 done depth 4 gdb stack info depth 12 done depth 12 gdb stack info depth 11 done depth 11 gdb stack info depth 13 done depth 12 gdb The st
386. smaller executable file sizes for large applications See your compiler release notes for more details e Support for debugging incrementally linked 64 bit programs This feature requires linker version B 11 18 or later on HP UX 11i v1 e Support to automatically preload librtc sl with chatr mem_check option This feature requires linker version B 11 61 and later on HP 9000 systems and linker version B 12 46 and later on Integrity systems mem_check option is used only for memory debugging e Support to automatically preload librtc sl with chatr rtc option This feature requires linker version B 11 66 and later on HP 9000 systems and linker version B 12 51 and later on Integrity systems However mem_check option is retained with the latest Linker version 14 2 2 Dependent Standard Library Routines for Run Time Checking The Run Time Checking feature Interactive and Batch Mode of WDB cannot be used with applications that re define or over ride the default system supplied versions of 140 HP UX Configuration Specific Information the standard library routines under libc so and 1libdld so The following standard libraries are dependencies for runtime checking abort atoi chdir dlsym strstr strcat ctime dlclose memchr strrchr dlgetname dlget clock gettime strlen dlhook dlmodinfo environ getenv strlen execl exit fclose fork strdup fope
387. space for you after the prompt you set This allows you to set a prompt which ends in a space or a prompt that does not set prompt newprompt Directs GDB to use newprompt as its prompt string henceforth show prompt Prints a line of the form Gdb s prompt is your prompt 17 2 Setting Command Editing Options in GDB GDB reads its input commands via the readline interface This gnu library provides consistent behavior for programs which provide a command line interface to the user Ad vantages are gnu Emacs style or vi style inline editing of commands csh like history substitution and a storage and recall of command history across debugging sessions You may control the behavior of command line editing in GDB with the command set set editing set editing Enable command line editing enabled by default on set editing off Disable command line editing show editing Show whether command line editing is enabled 17 3 Setting Command History Feature in GDB GDB can keep track of the commands you type during your debugging sessions so that you can be certain of precisely what happened Use these commands to manage the GDB command history facility To make command history understand your vi key bindings you need to create a inputrc file with the following contents 17 1 Setting the GDB Prompt 281 set editing mode vi set history filename fname set history save set history save on set history save off set hi
388. st_names kernel parameter is set It is supported only for the default utsname e The heap segment listed in the memory segment does not contain mmapped memory for the given core file 14 15 3 Support for the dumpcore command HP WDB provides the command dumpcore to generate a core image file for a process running under the debugger during execution The dumpcore command does not require any argument It saves the core image for the current process being debugged in the file named core lt pid gt where lt pid gt is the process ID number To dump the core for a live process you must pass the following commands gdb run Starting program sample Breakpoint 3 main at sample c 1010 b foo a gdb dumpcore Dumping core to the core file core 24091 gdb When starting from the HP WDB command line gdb file sample Reading symbols from sample done gdb set live core 1 gdb core file core 24091 Core was generated by sample 0 main at sample c 1010 b foo a gdb backtrace 0 main at sample c 10 gdb When starting from the shell prompt o gdb lcore a out core lt pid gt For example o gdb lcore sample core 24091 HP gdb Type show warranty for warranty support Core was generated by sample 0 main at sample c 10 gdb 14 15 3 1 Enhancements to the dumpcore command HP WDB provides an option for the dumpcore command to specify a lt core filename to generate a
389. story size size The readline interface uses the input rc file to control the settings Set the name of the GDB command history file to fname This is the file where GDB reads an initial command history list and where it writes the command history from this session when it exits You can access this list through history expansion or through the history command editing characters listed below This file defaults to the value of the environment variable GDBHISTFILE orto gdb_ history _gdb_history on MS DOS if this variable is not set Record command history in a file whose name may be specified with the set history filename command By default this option is disabled Stop recording command history in a file Set the number of commands which GDB keeps in its history list This defaults to the value of the environment variable HISTSIZE or to 256 if this variable is not set History expansion assigns special meaning to the character Since is also the logical not operator in C history expansion is o by default If you decide to enable history expansion with the set history expansion on command you may sometimes need to follow when it is used as logical not in an expression with a space or a tab to prevent it from being expanded The readline history facilities do not attempt substitution on the strings and even when history expansion is enabled The commands to control history expansion are set his
390. stribution If you want to modify the debugger sources to tailor GDB to your needs you may wish to do this The source distribution consists of a tar file containing the source tree rooted at gdb 4 17 The instructions that follow describe how to build a gdb executable from this source tree HP believes that these instructions apply to the WDB source tree that it distributes However HP does not explicitly support building a gdb for any non HP platform from the WDB source tree It may work but HP has not tested it for any platforms other than those described in the WDB Release Notes You can nd additional information specific to Hewlett Packard in the README HP WDB file at the root of the source tree GDB comes with a configure script that automates the process_of preparing GDB for installation you can then use make to build the gdb program The GDB distribution includes all the source code you need for GDB in a single directory whose name is usually composed by appending the version number to gdb For example the GDB version gdb 199991101 distribution is in the gdb gdb 199991101 directory That directory contains gdb gdb 199991101 configure and script for configuring GDB and all its supporting supporting files libraries gdb gdb 199991101 gdb the source specific to GDB itself gdb gdb 199991101 bfd source for the Binary File Descriptor library gdb gdb 199991101 include gnu include files edb gdb 199991101 libib
391. sync output contains supplementary information that the client should handle for example a new breakpoint information All notify output is prefixed by console stream output is output that should be displayed as is in the console It is the textual response to a CLI command All the console output is prefixed by target stream output is the output produced by the target program All the target output is prefixed by log stream output is output text coming from GDB s internals for instance messages that should be displayed as part of an error log All the log output is prefixed by amp New GDB MI commands should only output lists containing values See GDB MI stream records page 311 for more details about the various output records 21 1 GDB MI Command Syntax 309 21 1 3 Simple examples of GDB MI interaction This subsection presents several simple examples of interaction using the GDB MI interface In these examples gt means that the following line is passed to GDB MI as input while lt means the output received from GDB MI Evaluate expression Here is an example to evaluate an expression gt data evaluate expression 2 3 lt gdb lt done value 5 lt gdb and later lt stop reason SsStop address 0x123 source a c 123 lt gdb Simple CLI command Here is an example of a simple CLI command being passed through GDB MI and on to the CLI gt print 1 2 lt a
392. system and you can put it somewhere in memory where it will not get clobbered by the download target sim Builtin CPU simulator GDB includes simulators for most architectures In general the following commands work target sim load run However you cannot assume that a specific memory map device drivers or even basic I O is available although some simulators do provide these Some configurations may include these targets as well target nrom dev NetROM ROM emulator This target only supports downloading Different targets are available on different configurations of GDB your configuration may have more or fewer targets Many remote targets require you to download the executable code once you have successfully established a connection load filename Depending on what remote debugging facilities are configured into GDB the load command may be available Where it exists itis meant to make filename an executable available for debugging on the remote system by downloading or dynamic linking for example load also records the filename symbol table in GDB like the add symbol file command If your GDB does not have a 1oad command attempting to execute it gets the error message You can t do that when your target is The file is loaded at whatever address is specified in the executable For some object file formats you can specify the load address when you link the program for other formats like a out the o
393. t 2 col_name what colhdr What body bkpt number 1 type breakpoint disp keep enabled y addr 0x0001072c func main file recursive2 c line 4 times 0 bkpt number 2 type breakpoint disp del enabled y addr 0x00010774 func foo file recursive2 c line 11 times 0 gdb break insert r foo int foo int int done bkpt number 3 addr 0x00010774 file recursive2 c line 11 gdb The break list command Synopsis break list Displays the list of inserted breakpoints showing the following fields Number number of the breakpoint Type type of the breakpoint breakpoint or watchpoint Disposition should the breakpoint be deleted or disabled when it is hit keep or nokeep Enabled is the breakpoint enabled or no y or n Address memory location at which the breakpoint is set What logical location of the breakpoint expressed by function name file name line number Times number of times the breakpoint has been hit If there are no breakpoints or watchpoints the BreakpointTable body field is an empty list GDB command The corresponding GDB command is info break Example gdb break list done BreakpointTable nr_rows 2 nr_cols 6 21 5 GDB MI breakpoint table commands 317 hdr width 3 alignment 1 col_name number colhdr Num width 14 alignment 1 col_name type colhdr Type width
394. t command instead of the print command set is really the same as print except that the expression s value is not printed and is not put in the value history see Value history page 95 The expression is evaluated only for its effects The set command has a number of subcommands that conflict with the names of program variables The set variable command is a better alternative for setting program variables The following two examples illustrate the same e Example 1 gdb whatis width type double gdb p width 4 13 gdb set width 47 Invalid syntax in expression The invalid expression of course is 47 In order to actually set the program s variable width use e Example 2 gdb set var width 47 if your program has a variable g you run into problems if you try to set anew value with just set g 4 because GDB has the command set gnutarget abbreviated set g gdb whatis g type double 11 1 Assignment to variables 119 gdb pg Sl 1 gdb set g 4 gdb pg 2 1 gdb r The program being debugged has been started already Start it from the beginning y or n y Starting program home smith cc_progs a out home smith cc_progs a out can t open to read symbols Invalid bfd target gdb show g The current BFD target is 4 The steps shown above sets the gnutarget to an invalid value in place of the program variable g In order to set the variable g use
395. t makes future operations faster You typically combine the mappedand readnow options in order to build a syms file that contains complete symbol information See Commands to specify files page 125 for information on syms files A simple GDB invocation to do nothing but build a syms file for future use is gdb batch nx mapped readnow programname 2 1 2 Choosing modes You can run GDB in various alternative modes for example in batch mode or quiet mode nx n quiet silent q batch Do not execute commands found in any initialization files normally called gdbinit or gdb ini on PCs Normally GDB executes the commands in these files after all the command options and arguments have been processed See Command files page 289 Quiet Do not print the introductory and copyright messages These messages are also suppressed in batch mode Run in batch mode Exit with status 0 after processing all the command files specified with x and all commands from initialization files if not inhibited with 2 1 Invoking GDB 27 28 nowindows nw windows w cd directory dbx fullname f epoch Getting In and Out of GDB n Exit with nonzero status if an error occurs in executing the GDB commands in the command files Batch mode may be useful for running GDB as a filter for example to download and run a program on another computer in order to make t
396. t repeat if you press RET after using it You can use the mapped and readnow options just as with the symbol file command to change how GDB manages the symbol table information for filename The section command changes the base address of section SECTION of the exec file to ADDR This can be used if the exec file does not contain section addresses such as in the a out format or when the addresses specified in the file itself are wrong Each section must be changed separately The info files command described below lists all the sections and their addresses info files info target info files and info target are synonymous both commands print the current target see Chapter 13 page 133 including the names of the executable and core dump files currently in use by GDB and the files from which symbols were loaded Both the commands list all possible targets rather than the current targets All file specifying commands allow both absolute and relative file names as arguments GDB always converts the file name to an absolute file name and remembers it that way GDB automatically loads symbol definitions from shared libraries when you use the run command or when you examine a core file Before you issue the run command GDB does not understand references to a function in a shared library however unless you are debugging a core file On HP UX if the program loads a library explicitly GDB automatically loads the s
397. t stopped Likewise when you select a stack frame see Selecting a frame page 73 GDB prints the line where execution in that frame has stopped You can print other portions of source files by explicit command You can invoke GDB from its GNU Emacs interface to view the source code see Chapter 19 page 293 7 1 Printing source lines To print lines from a source file use the 1ist command abbreviated 1 By default ten lines are printed There are several ways to specify what part of the file you want to print The following forms of the 1ist command are used list linenum Prints lines centered around line number 1 inenumin the current source file list function Prints lines centered around the beginning of function function list Prints more lines The 1ist command prints lines following the lines printed by a previously executed 1ist command If the command prior to executing a 1ist just printed the stack frame then the 1ist command only prints the lines around that line list Prints lines just before the lines last printed By default GDB prints ten source lines with any of these forms of the 1i st command The number of lines printed by GDB can be set by the set listsize command The following two forms are supported set listsize count Makes the list command display count source lines unless the 1ist argument explicitly specifies some other number show listsize Displays the number of lines that list prints
398. tart address smaller than the address of 12 3 Errors reading symbol files 131 bad string table offset in symbol n unknown symbol type O0xnn stub type has NULL name const volatile indicator missing ok if using g v1 x got info mismatch between compiler and debugger 132 GDB Files the preceding source line This is known to occur in the SunOS 4 1 1 and earlier C compiler GDB circumvents the problem by treating the symbol scope block as starting on the previous source line Symbol number n contains a pointer into the string table which is larger than the size of the string table GDB circumvents the problem by considering the symbol to have the name foo which may cause other problems if many symbols end up with this name The symbol information contains new data types that GDB does not yet know how to read Oxnn is the symbol type of the uncomprehended information in hexadecimal GDB circumvents the error by ignoring this symbol information This usually allows you to debug your program though certain symbols are not accessible If you encounter such a problem and feel like debugging it you can debug gdb with itself breakpoint on complain then go up to the function read_dbx_ symtab and examine bufp to see the symbol GDB could not nd the full definition for a struct or class The symbol information for a C member function is missing some information that recent versions of the compiler shoul
399. tbreak args hbreak args does not leave an active breakpoint If you use break without an argument in the innermost frame GDB stops the next time it reaches the current location this may be useful inside loops GDB normally ignores breakpoints when it resumes execution until at least one instruction has been executed If it did not do this you would be unable to proceed past a breakpoint without first disabling the breakpoint This rule applies whether or not the breakpoint already existed when your program stopped Set a breakpoint with condition cond evaluate the expression cond each time the breakpoint is reached and stop only if the value is nonzero that is if cond evaluates as true stands for one of the possible arguments described above or no argument specifying where to break See Break conditions page 59 for more information on breakpoint conditions Set a breakpoint enabled only for one stop args are the same as for the break command and the breakpoint is set in the same way but the breakpoint is automatically deleted after the first time your program stops there See Disabling breakpoints page 58 Set a hardware assisted breakpoint args are the same as for the break command and the breakpoint is set in the same way but the breakpoint requires hardware support and some target hardware may not have this support The main purpose of this is EPROM ROM code debugging so you can set a bre
400. te the following command chatr B immediate lt executable gt In addition modify all the calls to shl_load to specify BIND_IMMEDIATE To perform command line calls after attaching a running process to GDB you must execute one of the following commands e opt langtools bin pxdb s on lt executable gt e chatr dbg enable lt executable gt 14 35 2 Additional support for command line calls in a stripped executable HP WDB enables you to perform command line calls in a stripped executable The various scenarios in which you can make command line calls in a stripped executable are as follows 14 35 2 1 For 32 bit applications To perform command line calls in a shared library without the help of dynamic linker using end o you must perform the following operations e Execute the chatr B immediate lt executable gt command e Modify all the calls to shl_load to specify BIND_IMMEDIATE if any To perform command line calls after attaching GDB to a running process without the help of dynamic linker using end o you must do the following for the program e Execute the chatr B immediate lt executable gt command e Modify all the calls to shl_load to specify BIND_IMMEDIATE if any e Execute the opt langtools bin pxdb s on lt executable gt or chatr dbg enable lt executable gt command On HP UX 11i v3 Integrity systems WDB enables automatic debugging of shared libraries without them being mapped private while attaching to a ru
401. ter attaching GDB to a running process complete the following steps 14 11 Thread Debugging Support 187 1 Set LD_LIBRARY_PATH to include the appropriate directory by entering one of the following commands e For 32 bit IPF applications LD LIBRARY PATH opt langtools wdb lib hpux32 e For 64 bit IPF applications LD LIBRARY PATH opt langtools wdb lib hpux64 e For 32 bit PA applications LD LIBRARY PATH opt langtools wdb lib e For 64 bit PA applications LD LIBRARY PATH opt langtools wdb lib pa20_ 64 2 Complete one of the following steps to preload the 1ibrtc runtime library e Set the target application to preload librtc by using the rtc option for the chatr command In addition to automatically loading the 1ibrtc library the rtc option for the chatr command also maps the shared libraries as private To enable or disable the target application to preload the librtc runtime library enter the following command at the HP UX prompt chatr rtc lt enable disable gt lt executable gt A NOTE The chatr rtc option preloads the 1ibrtc runtime library from the following default paths For 32 bit IPF applications opt langtools lib hpux32 librtc so For 64 bit IPF applications opt langtools lib hpux64 librtc so For 32 bit PA applications opt langtools lib librtc sl For 64 bit PA applications opt langtools lib pa20_ 64 librtc sl To preload the 1ibrtc runtime lib
402. teutea tery 355 21 T4GDB MI variable ODCCES x csucas tei ets dene si nna suse tan ie tuhas E E a iak 355 22 Reporting BUGS iN GDB eoor ings eA ard aat ia EE EE E NE Ee OSun estan des EI NE 361 22 1 Have you found a DUG 2s sich cesdies Leducusuailaersacteosapnoeiabas R Eir Eri SNE E E aaae 361 22 2 How COTO PORE DUG Si sssi suririnte reni n i cada aE Eaa iip aieri ea eies avi 361 Aslinstalling GDB ai aeaa a a a AA a eea e a EA a ae aaa 365 A 1 Compiling GDB in another CirectOry ciccc ctcssarieasdoensscsrdegnneveesrratdedienendd urseenndentanesceiy 366 A 2 Specifying names for hosts arid tare ets 4 ec ccts ish yeestdspactess escent seeseabuanstalspeeciageds 367 PD conf ig re VOTING Fas sae enei ei nave Dees Sates pao cones as cay ea cote 368 12 Table of Contents List of Tables 14 1 16 1 16 2 16 3 16 4 16 5 16 6 16 7 16 8 16 9 16 10 16 11 16 12 16 13 16 14 16 15 16 16 16 17 16 18 16 19 16 20 16 21 16 22 16 23 16 24 16 25 16 26 16 27 16 28 16 29 16 30 21 1 Memory Debugging Commands in Interactive and Batch Mode cccceeeeees 177 INVOCATION COMMAS asnan n a A TE AO ATI EAG 254 Window mode commands aanren eE AA AAA EEE AE ANTEA AEEA ERa N 254 File viewing COMMANC Ssss soane ei ie eii ii aaeaeaees 255 Data viewing and modification commands ssi vic cuit ecvesssnexcessiestaassyymnceadiateaartyuttonse 257 Stack viewing command Sis iseni nei ieee E E a 258 Status viewing COMMAS 5 tess rele ates Caeser
403. that permits automatic relinking of modules you should leave symbol reloading off since otherwise GDB may discard symbols when linking large programs that may contain several modules from different directories or libraries with the same name 117 set opaque type resolution on set opaque type resolution off show opaque type resolution maint print symbols filename maint print psymbols filename maint print msymbols filename 118 Examining the Symbol Table show Show the current on or of f symbol reloading setting Tell GDB to resolve opaque types An opaque type is a type declared as a pointer toa struct class or union for example struct MyType that is used in one source file although the full declaration of struct MyType is in another source file The default is on A change in the setting of this subcommand will not take effect until the next time symbols for a file are loaded Tell GDB not to resolve opaque types In this case the type is printed as follows lt no data fields gt Show whether opaque types are resolved or not Write a dump of debugging symbol data into the file ilename These commands are used to debug the GDB symbol reading code Only symbols with debugging data are included If you use maint print symbols GDB includes all the symbols for which it has already collected full details that is filename reflects symbols for only those files whose symbols GDB has read Y
404. the chatr command In addition to automatically loading the 1ibrtc library the rtc option for the chatr command also maps the shared libraries as private To enable or disable the target application to preload the librtc runtime library enter the following command at the HP UX prompt chatr rtc lt enable disable gt lt executable gt A NOTE The chatr rtc option preloads the 1ibrtc runtime library from the following default paths For 32 bit IPF applications opt langtools lib hpux32 librtc so For 64 bit IPF applications opt langtools lib hpux64 librtc so For 64 bit PA applications opt langtools lib pa20_64 librtc sl To preload the librtc runtime library from a path that is different from the default paths you must use the LD_PRELOAD environment variable OR e Instead of automatically preloading 1ibrtc and mapping the shared libraries you can explicitly preload the required 1ibrtc library after mapping the shared libraries private In the case of HP 9000 systems you must explicitly map the share libraries as private by using the dbg enable option for the chat r command as follows chatr dbg enable lt executable gt This step is not required on Integrity systems To explicitly preload the librtc runtime library and start the target application enter one of the following commands For 32 bit IPF applications LD_PRELOAD opt langtools lib hpux32 librtc so lt executab
405. the XDB and equivalent WDB commands for creating breakpoints Table 16 10 Breakpoint creation commands XDB Command WDB Equivalent Set a breakpoint at the specified location b b Set a breakpoint at the current line ba address ba address with xdb b address Set breakpoint at a code address bb depth No equivalent use b proc Set breakpoint at procedure beginning Set an instance breakpoint at the first executable line of expr proc bi expr proc b class proc cond bnum this expr Set an instance breakpoint at first executable line No equivalent of all non static member functions of the instance of a class no base classes bi c expr No Equivalent Set an instance breakpoint at first executable line of all non static member functions of the instance s class base classes included bi C expr No equivalent 16 2 Overall breakpoint commands 261 Table 16 10 Breakpoint creation commands continued 16 2 3 Breakpoint status commands XDB Command WDB Equivalent Meaning bpc c class rb class Set a class breakpoint at first executable line of all member functions of the instance s class no base classes bpe C class Use rb class for base Set a class breakpoint at first ex classes also ecutableUse rb class for base classes also line of all member functions of the class base classes included bpo proc rb pro
406. the argument list when you ask for completion on an overloaded symbol For more information about overloaded functions see C expressions page 109 You can use the command set overload resolution off to disable overload resolution see GDB features for C page 111 3 3 Getting help You can always ask GDB itself for information on its commands using the command help help h You can use help abbreviated h with no arguments to display a short list of named classes of commands gdb help List of classes of commands aliases Aliases of other commands breakpoints Making program stop at certain points data Examining data files Specifying and examining files internals Maintenance commands obscure Obscure features running Running the program stack Examining the stack status Status inquiries support Support facilities tracepoints Tracing of program execution without stopping the program user defined User defined commands Type help followed by a class name for a list of commands in that class Type help followed by command name for full documentation Command name abbreviations are allowed if unambiguous gdb 3 3 Getting help 35 help class Using one of the general help classes as an argument you can get a list of the individual commands in that class For example here is the help display for the class status gdb help status Status inquiries
407. the bottom row of softkeys The function keys F9 and up correspond to the top row 14 31 3 Specifying foreground and background colors To change the foreground and background colors update the Xdefaults file in the home directory The resources are the same as for hpterm Here is a sample entry HPterm foreground white HPterm background rgb 68 90 C4 14 31 4 Using the X window graphical interface To start Visual Interface for WDB in graphical mode with mouse support run Visual Interface for WDB with the command opt langtools bin vdb Visual Interface for WDB opens an hpterm window ignoring the value of the TERM environment variable for debugging a program With a mouse you can do the following e Left click the line number to insert or remove breakpoints e Left click an identifier to select the identifier as an operand for the Print Print Type and List softkeys e Where necessary manually select an expression by dragging the cursor over it e Right click the line number to activate a pop up menu with several useful commands e Right click an identifier to automatically select it and use the selection as an operand for the pop up window that appears e Right click an empty region for a third pop up menu with several useful actions For example see Saving the contents of a debugging session to a file page 237 e Left click the command softkeys at the bottom of Visual Interface for WDB windo
408. the conditions There is absolutely no warranty for Wildebeest Type show warranty for details Type lt return gt to continue or q lt return gt to quit Wildebeest was built for PA RISC 1 1 or 2 0 narrow HP UX 11 00 gdb The terminal window is divided into two panes a Source pane at the top and a Command pane at the bottom In the middle isa locator bar that shows the current file procedure line and program counter PC address when they are known to the debugger When you set a breakpoint on the main program by issuing the command b main an asterisk appears opposite the first executable line of the program 15 1 Starting the TUI 243 When you execute the program up to the first breakpoint by issuing the command run a right angle bracket gt points to the current location So after you issue those commands the window looks something like this 29 int main void 30 31 Try two test cases gt 32 print_average my_list first last 33 print_average my_list first last 3 File average c Procedure main Line 32 pe 0x3524 gdb b main Breakpoint 1 at 0x3524 file average c line 32 gdb run Starting program home work wdb a out Breakpoint 1 main at average c 32 gdb 15 2 Automatically running a program at startup WDB does not start running the target executable at startup as do xdb and HP DDE This makes it easy to set break points before the target progra
409. the initial GDB has four standard register names that are available in expressions on most machines whenever they do not conflict with an architecture s canonical mnemonics for registers The register names pc and sp are used for the program counter register and the stack pointer fp is used for a register that contains a pointer to the current stack frame and ps is used for a register that contains the processor status For example you could print the program counter in hex with p x Spc or print the instruction to be executed next with x i Spc or add four to the stack pointer withwith set Ssp 4 Whenever possible these four standard register names are available on your machine even though the machine has different canonical mnemonics so long as there is no conflict The info registers command shows the canonical names For example on the SPARC info registers displays the processor status register as psr but you can also refer to it as ps and on x86 based machines ps is an alias for the EFLAGS register GDB always considers the contents of an ordinary register as an integer when the register is examined in this way Some machines have special registers which can hold nothing but floating point these registers are considered to have floating point values There is no way to refer to the contents of an ordinary register as floating point value although you can print it as a floating point value with print f regn
410. their use gdb h is a shorter equivalent 2 1 Invoking GDB 25 All options and command line arguments you give are processed in sequential order The order makes a difference when the x option is used 2 1 1 Choosing files When GDB starts it reads any arguments other than options as specifying an executable file and core file or process ID This is the same as if the arguments were specified by the se and c options respectively GDB reads the first argument that does not have an associated option flag as equivalent to the se option followed by that argument and the second argument that does not have an associated option flag if any as equivalent to the c option followed by that argument If GDB has not been configured to included core file support such as for most embedded targets then it will complain about a second argument and ignore it Many options have both long and short forms both are shown in the following list GDB also recognizes the long forms if you truncate them so long as enough of the option is present to be unambiguous If you prefer you can flag option arguments with rather than though we illustrate the more usual convention symbols file s file Read symbol table from file file exec file e file Use file file as the executable file to execute when appropriate and for examining pure data in conjunction with a core dump se file Read symbol table from file file and
411. this is not formally supported by Hewlett Packard these two do work together Note however if you have ddd issues you ll need to report them to the ddd support channel 14 33 Support for XDB commands HP WDB provides support for a subset of XDB commands enabled with the xdb option 14 33 1 stop in at dbx commands The commands lt stop in function address gt and lt stop at line gt are equivalent of dbx lt break function address line gt command WDB supports the lt stop in at gt command in non dbx mode For example gdb a out gdb stop in main Breakpoint 1 at 0x2a34 file list c line 18 from tmp a out gdb stop at 25 Breakpoint 2 at Ox2a6c file list c line 25 from tmp a out gdb 14 34 GNU GDB Logging Commands The following commands control GDB logging activities e set logging file Set the current log file e set logging of f Set logging off e set logging on Set logging on e set logging overwrite on off Set whether logging overwrites or appends to the log file e set logging redirect on off Set the logging output mode 14 35 Support for command line calls in a stripped executable HP WDB enables you to perform command line calls in a stripped executable 238 HP UX Configuration Specific Information 14 35 1 Support for command line calls in a stripped executable on PA RISC systems In WDB to perform command line calls in a shared library without the help of dynamic linker using end o you must execu
412. thread debugging features of HP WDB NOTE This feature is available only for compiler versions A 06 20 and later It is a convenient way of launching the batch mode advanced thread checking features without setting any other environment variables at runtime In other words batch mode thread checking has two modes of invocation The first method is to use the run time environment variables LD_LIBRARY_PATH LD_PRELOAD and BATCH_RTC on existing precompiled applications The second method is to use the check thread option at the compile time check thread must only be used with multithreaded programs It is not enabled by check a11 This functionality requires HP WDB 5 9 or later The default configuration used by check thread option is as follows thread check 1 recursive relock 1 unlock not own 1 mix sched policy 1 cv multiple mxs 1 cv wait no mx 1 thread exit own mutex 1 thread exit no join detach 1 stack util 80 num waiters 0 frame_count 4 output_dir 14 11 Thread Debugging Support 193 Behavior of the check thread option can be changed by users by providing their own rtcconfig file The user specified rt cconfig file can be in the current directory or in a directory specified by the GDBRTC_CONFIG environment variable If any thread error condition is detected during the application run the error log will be output to a file in the current working directory The output file will have the following naming convention
413. tinue you can experiment with various ways of fixing problems until you are satisfied with the correction before you exit the debugger 14 7 Fix and continue debugging 145 The advantages include e You do not have to recompile and relink the entire program e You do not have to reload the program into the debugger e You can resume execution of the program from the x location e You can speed up the development cycle gt NOTE Fix and Continue is only supported with the most recent versions of HP C and HP aC on PA RISC systems In command line mode you use the edit command before invoking the fix command The edit command has the following syntax edit file1 file2 where file represents one or more source files for the current executable If you do not specify a file name WDB edits the currently open source file When you edit a file with the edit command and save the changes the original source file contains the changes even if you do not use the ix command to recompile the program in the debugger 14 7 1 Fix and Continue compiler dependencies Fix and Continue is supported only for PA RISC on HP UX 11 x with these compilers e HP C ANSI C A 11 01 20 or later e HP aC A 03 25 or later e HP Fortran 90 2 4 or later 14 7 2 Fix and Continue restrictions Fix and Continue has the following restrictions and behaviors e You cannot recompile code that has been optimized e You cannot add delete or reorder t
414. tion using the HP aC version A 03 50 or later with the g0 option In C the steplast command is helpful while debugging heavy templated functions because it directly steps into the call thus skipping the constructor calls if any This behavior is unlike the step command that steps into the constructor itself Consider the following example void call_me string s gdb 10 call _ me hello gdb steplast call_me s static npos 4294967295 static nullref ref_hdr mutex_ dummyl 0x7f4f79e0 dummy2 2136325568 refs 2136327612 capacity_ 2136327468 nchars_ 2136327464 eos _ char 64 alloc_ lt No data fields gt value_allocator alloc_ 0x7 7 133c data_ 0x40003a64 hello at str C 55 printf Will just print the value of n If there are multiple top level calls the steplast command enables you to step into each top level call For example for the following line the steplast command takes you to the first top level call foo foo bar bar foo Debug foo use the finish command to exit from the first top level call foo execute the steplast command to step into the next top level call bar The following example illustrates the use of steplast command gdb 10 foo bar bar foo gdb sl Use the steplast sl command to step 14 28 Getting information from a non debug executable You can get some information about the arguments passed to the
415. tomatically uses the new executable and picks up the debugging session where you stopped before using the edit command For example you can continue stepping through the program and you will nd the new return total statement in the source view You can print the value of total and see that the result is 110 14 7 Fix and continue debugging 149 10 When you finish with the debugging session you can exit the debugger normally gdb q The following modules in dev src mysum have been fixed dev src sum c Remember to remake the program The debugger message lists the source files that you have changed during the debugging session A NOTE You must rebuild the program after you use the fix command because the changes you make are temporarily patched into the executable image The changes are lost when you exit the debugger or you load a different executable 14 8 Inline Support HP WDB enables you to debug inline functions in applications compiled with g option To enable inline debugging in HP 9000 systems the applications must be compiled with the inline_ debug option introduced in the A 03 65 and later versions of the HP aC compiler In Integrity systems the applications that are compiled with g option support inline debugging by default and require no additional options Compiler versions A 06 02 and later support the inline debugging feature in Integrity systems 14 8 1 Inline Debugging in HP 9000 Systems To debu
416. tory expansion on set history expansion set history expansion off show history show history filename show history save show history size show history expansion 282 Controlling GDB Enable history expansion History expansion is o by default Disable history expansion The readline code comes with more complete documentation of editing and history expansion features Users unfamiliar with GNU Emacs or vi may wish to read it These commands display the state of the GDB history parameters show history by itself displays all four states show commands Display the last ten commands in the command history show commands n Print ten commands centered on command number n show commands Print ten commands just after the commands last printed 17 4 Setting the GDB Screen Size Certain commands to GDB may produce large amounts of information output to the screen To help you read all of it GDB pauses and asks you for input at the end of each page of output Type RET when you want to continue the output or q to discard the remaining output Also the screen width setting determines when to wrap lines of output Depending on what is being printed GDB tries to break the line at a readable place rather than simply letting it over flow onto the following line Normally GDB knows the size of the screen from the terminal driver software For example on Unix GDB uses the termcap data base together with the value of the TERM e
417. type errors have nothing to do with the language in use and usually arise from expressions such as the one described above which make little sense to evaluate anyway Each language defines to what degree it is strict about type For instance C requires the arguments to arithmetical operators to be numbers In C enumerated types and pointers can be represented as numbers so that they are valid arguments to mathematical operators See Supported languages page 105 for further details on specific languages GDB provides some additional commands for controlling the type checker set check type auto Set type checking on or off based on the current working language See Supported languages page 105 for the default settings for each language set check type on set Settype checking on or off overriding the default setting check type off for the current working language Issue a warning if the setting does not match the language default If any type mismatches occur in evaluating an expression while type checking is on GDB prints a message and aborts evaluation of the expression set check type warn Cause the type checker to issue warnings but to always attempt to evaluate the expression Evaluating the expression may still be impossible for other reasons For example GDB cannot add numbers and structures show type Show the current setting of the type checker and whether or not GDB is setting it automatically 9 3 2 An
418. ugh the gdb mi interface using stream records Each stream record begins with a unique prefix character which identifies its stream see GDB MI Output syntax page 308 In addition to the prefix each stream record contains a string output This is either raw text with an implicit new line or a quoted C string which does not contain an implicit new line string output The console output stream contains text that should be displayed in the CLI console window It contains the textual responses to CLI commands string output The target output stream contains any textual output from the running target amp string output The log stream contains internal debugging messages being produced by GDB GDB MI out of band records Out of band records are used to notify the GDB MI client of additional changes that have occurred Those changes can either be a consequence of GDB MI for example a breakpoint modified or a result of target activity for example target stopped The following is a preliminary list of possible out of band records We stop 21 4 GDB MI command description format The remaining sections describe blocks of commands Each block of commands is laid out in a fashion similar to this section 21 3 GDB MI output records 311 Note the line breaks shown in the examples are here only for readability They do not appear in the real output Also note that the commands with a non available example N A ar
419. uired because this usage is normal and expected application behavior The set thread check cv wait no mx on off checks if the associated mutex of a condition variable is locked when the thread calls the pthread_cond_wait routine The debugger transfers the execution control to the user and prints a warning message when this condition is detected This check is not a POSIX 1 standard requirement for the pthread_cond_wait routine It is an additional check provided by WDB The set thread check thread exit own mutex on off command checks if any thread has terminated execution without unlocking the mutexes or 14 11 Thread Debugging Support 185 thread exit no join detach on off stack util num 186 HP UX Configuration Specific Information read write locks that are associated with the thread The debugger transfers the execution control to the user and prints a warning message when this condition is detected This situation can result in deadlocks if other threads are waiting to acquire the locked mutexes or read write locks The set thread check thread exit no join detach on off command checks if a thread has terminated execution either successfully or because of an exception or a cancel without joining or detaching the thread The debugger transfers the execution control to the user and prints a warning message when this condition is detected The resources associated with a terminated thread continue to exist i
420. uivalent r with xdb tui data with tui gdb xdb tui program fr display fregs tui with xdb tui with fr Meaning Scroll floating point registers forward or backward src cmd and asmare also valid window names Display floating point registers 254 XDB to WDB Transition Guide Table 16 2 Window mode commands continued 16 1 3 File viewing commands XDB Command WDB Equivalent Meaning gr gr with xdb tui Display general registers display regs with tui sr sr with xdb tui Display special registers display sregs with tui td td with xdb tui Toggle disassembly mode tf tf with xdb tui Toggle float register display toggle fregs with tui precision ts ts with xdb tui Toggle split screen mode u u with xdb tui Update screen to current execution update with tui point V U with xdb tui Refresh all windows refresh with tui w number w number with xdb Set size of source window tui winheight src number with tui The following table lists the XDB and the equivalent WDB commands for viewing source files Table 16 3 File viewing commands XDB Command WDB Equivalent number with tui note that a space is required between or and the number number Move view location forward or backward in source file number lines
421. ult address info breakpoints to the address of the last breakpoint listed info line to the starting address of a line and print if you use it to display a value from memory For example x 3uh 0x54320 is a request to display three halfwords h of memory formatted as unsigned decimal integers u starting at address 0x54320 x 4xw sp prints the four words w of memory above the stack pointer here sp see Registers page 98 in hexadecimal x Since the letters indicating unit sizes are all distinct from the letters specifying output formats you do not have to remember whether unit size or format comes first either order works The output specifications 4xw and 4wx mean exactly the same thing However the count n must come first wx4 does not work Even though the unit size u is ignored for the formats s and i you might still want to use a count n for example 3i specifies that you want to see three machine instructions including any operands The command disassemble gives an alternative way of inspecting machine instructions see Source and machine code page 80 All the defaults for the arguments to x are designed to make it easy to continue scanning memory with minimal specifications each time you use x For example after you have inspected three machine instructions with x 3i addr you can inspect the next seven with just x 7 If you use RET to repeat the x command the repeat c
422. upport for GAG eisenii iinei iiini eas sa de Es E EEEE EE EEE E eves 238 14 33 Support for XDB command S ssssssssesssessssseersersseseesserssisneeseessieseeseessersesresseessesees 238 14 33 1 stop in at dbx commandSasccnerssterni nearne eA a 238 14 34 GNU GDB Logging COMMA Ss ciiseseussesiivittentoccnsvavicuubers bond deavsenpbnedoddeyesunedunapangedys 238 14 35 Support for command line calls in a stripped executable ccccceseseeseeeeereees 238 14 35 1 Support for command line calls in a stripped executable on PA RISC BY SUS EE pass estou nasa ess eer na eas ede ca tava va nos oa ua ehrese E E 239 14 35 2 Additional support for command line calls in a stripped executable 239 14 35 21 For 32 bit applications insiens aaie ananira ier 239 14 35 2 2 For 64 bit applications sssrini iisi dinei iiia 240 14 35 3 Support for debugging stripped Dinaries cccceccceeseeee cess ceeeseeeeeeneenees 240 Table of Contents 9 14 35 3 1 Printing of locals and globals in a stripped module ceceeeeees 240 14 35 3 2 Backtrace on stripped LPaIMes vic visi sseae cra csegnsgubeesnrauniad onienerd oot nena bains 240 14 35 3 3 Command line calls to non stripped liDrary eee eee eeeeeee enone 240 14 35 3 4 Setting breakpoints in unstripped shared library cceseeeeeeees 240 14 36 Displaying the current block scope informatiON cccescseeseeseeeeeeseenetseeeneees 241 TAZ Ae SUID PONG scent cus
423. ur program has requested an alarm Some signals including SIGALRM are a normal part of the functioning of your program Others such as SIGSEGV indicate errors these signals are fatal they kill your program immediately if the program has not specified in advance some other way to handle the signal SIGINT does not indicate an error in your program but it is normally fatal so it can carry out the purpose of the interrupt to kill the program GDB has the ability to detect any occurrence of a signal in your program You can tell GDB in advance what to do for each kind of signal Normally GDB is set up to ignore non erroneous signals like SIGALRM so as not to interfere with their role in the functioning of your program but to stop your program immediately whenever an error signal happens You can change these settings with the handle command 5 3 Signals 67 A NOTE Use caution if you disable all signals from certain processes Disabling SIGTRAP in your program may cause your program to hang HP UX uses SIGTRAP to communicate with the debugger If you disable all signals from certain processes so that signals will be delivered to the right process your program may hang when you try to debug it This behavior occurs because if you disable SIGTRAP the debugger no longer receives notification of events such as breakpoint hits and loading or unloading of shared libraries To prevent this problem Make certain you set this fla
424. urrently selected use either info target or info files see Commands to specify files page 125 Describe a particular target including any parameters necessary to select it GDB uses its own library BFD to read your files GDB knows whether it is reading an executable a core ora o file however you can specify the file format with the set gnutarget command Unlike most target commands with gnutarget the target refers to a program not a machine Warning To specify a file format with set gnutarget you must know the actual BFD name See Commands to specify files page 125 Use the show gnutarget command to display what file format gnutarget is set to read If you have not set gnutarget GDB will determine the file format for each file automatically and show gnutarget displays The current BDF target is auto Here are some common targets available or not depending on the GDB configuration target exec program target core filename target remote dev 134 Specifying a Debugging Target An executable file target exec programis the same as exec file program A core dump file target core filename is the same as core file filename Remote serial target in GDB specific protocol The argument dev specifies what serial device to use for the connection for example dev ttya target remote supports the load command This is only useful if you have some other way of getting the stub to the target
425. use it as the executable file core file c file Use file file as a core dump to examine c number Connect to process ID number as with the attach command unless there is a file in core dump format named number in which case c specifies that file as a core dump to read command file x file Execute GDB commands from file file See Command files page 289 directory directory d directory Add directory to the path to search for source files 26 Getting In and Out of GDB m mapped r readnow Warning this option depends on operating system facilities that are not supported on all systems If memory mapped files are available on your system through the mmap system call you can use this option to have GDB write the symbols from your program into a reusable file in the current directory If the program you are debugging is called tmp fred the mapped symbol file is tmp fred syms Future GDB debugging sessions notice the presence of this file and can quickly map in symbol information from it rather than reading the symbol table from the executable program The syms file is specific to the host machine where GDB is run It holds an exact image of the internal GDB symbol table It cannot be shared across multiple host platforms Read each symbol file s entire symbol table immediately rather than the default which is to read it incrementally as it is needed This makes startup slower bu
426. ust as you do in C source they are automatically dereferenced In the parameter list shown when GDB displays a frame the values of reference variables are not displayed unlike other variables this avoids clutter since 9 4 Supported languages 109 A references are often used for large structures The address of a reference variable is always shown unless you have specified set print address off 5 GDB supports the C name resolution operator your expressions can use it just as expressions in your program do Since one scope may be defined in another you can use repeatedly if necessary for example in an expression like scopel scope2 name GDB also allows resolving name scope by reference to source files in both C and C debugging see Program variables page 84 In addition when used with the HP aC compiler GDB supports calling virtual functions correctly printing out virtual bases of objects calling functions in a base subobject casting objects and invoking user defined operators NOTE GDB cannot display debugging information for classes or functions defined in a shared library that is not compiled for debugging with the g0 option GDB displays the function with the message lt no data fields gt For example after d3 is created by the following line RWCollectableDate d3 15 5 2001 printing the variable or class returns gdb p d3 3 lt No data fields gt gdb ptype RW
427. utable and core set write off files for both reading and writing if you specify set write of f the default GDB opens them as read only If you have already loaded a file you must load it again using the exec file or core file command after changing set write for your new setting to take effect 122 Altering Execution show write Display whether executable files and core files are opened for writing as well as reading 11 6 Patching programs 123 124 12 GDB Files GDB needs to know the file name of the program to be debugged both in order to read its symbol table and in order to start your program To debug a core dump of a previous run you must also tell GDB the name of the core dump file 12 1 Commands to specify files You can specify executable and core dump file names as arguments to the GDB start up command see Getting In and Out of GDB page 25 Occasionally it is necessary to change to a different file during a GDB session In these situations the GDB commands to specify new files are useful file filename file exec file filename Use filename as the program to be debugged It is read for its symbols and for the contents of pure memory It is also the program executed when you use the run command If you do not specify a directory and the file is not found in the GDB working directory GDB uses the environment variable PATH as a list of directories to search just as the shell does when l
428. ution without giving a signal This is useful when your program stopped on account of a signal and would ordinary see the signal when resumed with the continue command signal 0 causes it to resume without a signal signal does not repeat when you press RET a second time after executing the command Invoking the signal command is not the same as invoking the ki11 utility from the shell Sending a signal with kil1 causes GDB to decide what to do with the signal depending on the signal handling tables see Signals page 67 The signal command passes the signal directly to your program 11 4 Returning from a function You can use the following command to return from a function 11 3 Giving your programa signal 121 return return You can cancel execution of a function call with the return expression command If you give an expressionargument its value is used as the return value from the function value When you use return GDB discards the selected stack frame and all frames within it You can think of this as making the discarded frame return prematurely If you wish to specify a value to be returned give that value as the argument to return This pops the selected stack frame see Selecting a frame page 73 and any other frames inside of it leaving its caller as the innermost remaining frame That frame becomes selected The specified value is stored in the registers used for returning values of functions The retu
429. vel 3 addr 0x000107a4 func foo file recursive2 c line 14 frame level 4 addr 0x000107a4 func foo file recursive2 c line 14 frame level 5 addr 0x000107a4 func foo file recursive2 c line 14 gdb Show a single frame 344 The GDB MI Interface gdb stack list frames 3 3 done stack frame level 3 addr 0x000107a4 func foo file recursive2 c line 14 gdb The stack list locals command Synopsis stack list locals print values Display the local variable names for the current frame With an argument of 0 prints only the names of the variables with argument of 1 prints also their values GDB command info locals in GDB gdb_ get locals in gdbtk Example gdb stack list locals 0 done locals name A name B name C gdb stack list locals 1 done locals name A value 1 name B value 2 name C value 3 gdb The stack select frame command Synopsis stack select frame framenum Change the current frame Select a different frame framenum on the stack GDB command The corresponding GDB commands are frame up down select frame up silent and down silent Example gdb stack select frame 2 done gdb 21 9 GDB MI Stack Manipulation Commands 345 21 10 GDB MI Symbol query commands The symbol info address command Synopsis symbol info address symbol Describe w
430. w e Click the middle button to paste the selection e Drag the status bar with the mouse to resize the debugger window relative to the source window 14 31 Visual Interface for WDB 235 14 31 5 Using the TUI mode A To start Visual Interface for WDB in terminal user interface TUI mode run Visual Interface for WDB with the command opt langtools bin vdb tui This mode works well with hptermand xterm and fairly well with dt term and VT100 telnet terminals NOTE A defect in dtterm may truncate the display of lines that do not t within the window To work around this defect refresh the display with CTRL L or widen the terminal window so source lines do not wrap If you use xterm and dtterm update the Xdefaults file with keyboard translations to get the shifted arrows and shifted paging keys to work For xterm use the following XTerm vt100 translations override Shift lt Key gt Prior string 0x2 n Shift lt Key gt Next string 0x6 n Shift lt Key gt Up string 0x5 n Shift lt Key gt Down string 0x19 n Shift lt Key gt Left string 0xlb string i n Shift lt Key gt Right string 0xlb string la For dterm use the following DtTerm Translations override n Shift lt Key gt osfPageUp string 0x2 n Shift lt Key gt osfPageDown string 0x6 n Shift lt Key gt osfUp string 0x5 n Shift lt Key gt osfDown string 0x19 n Shift lt Key gt osfLeft string 0x1lb str
431. which are a special kind of user defined command Whenever you run the command foo if the user defined command hook foo exists it is executed with no arguments before that command In addition a pseudo command stop exists Defining hook stop makes the associated commands execute every time execution stops in your program before breakpoint commands are run displays are printed or the stack frame is printed For example to ignore SIGALRM signals while single stepping and treat them normally during normal execution you could define define hook stop handle SIGALRM nopass end define hook run handle SIGALRM pass 288 Canned Sequences of Commands end define hook continue handle SIGLARM pass end You can define a hook for any single word command in GDB and not for command aliases Also you should define a hook for the basic command name for example backtrace rather than bt If an error occurs during the execution of your hook execution of GDB commands stops and GDB issues a prompt before the command that you actually typed had a chance to run If you try to define a hook which does not match any known command GDB issues a warning from the define command 18 3 Command files A command file for GDB is a file of lines that are GDB commands Comments lines starting with may also be included An empty line in a command file does nothing it does not mean to repeat the last command as it would from the terminal W
432. xWorks with an argument to GDB see Chapter 2 page 25 or by using the file or exec file command see Commands to specify files page 125 NOTE If you are running your program in an execution environment that supports processes run creates an inferior process and makes that process run your program In environments without processes run jumps to the start of your program The execution of a program is affected by the information it receives from the parent process You must provide GDB the information before starting the program You can change the information after starting your program but such changes only affect your program the next time you start it The information that must be passed to GDB can be categorized into four categories arguments Specify the arguments to give your program as the arguments of the run command If a shell is available on your target the shell is used to pass the arguments so that you may use normal conventions such as wildcard expansion or 4 1 Compiling for debugging 39 40 environment working directory standard input and output Running Programs Under GDB variable substitution in describing the arguments On Unix systems you can control which shell is used with the SHELL environment variable GDB uses the C shell usr bin csh See Arguments To Your Program page 41 Your program inherits its environment from GDB However you can use the GDB commands
433. xiliary breakpoint commands e Breakpoint creation commands e Breakpoint status commands e All procedures breakpoint commands e Global breakpoint commands 16 1 By function lists of XDB commands and HP WDB equivalents 253 e Assertion control commands e Record and playback commands e Macro facility commands e Signal control commands e Miscellaneous commands 16 1 1 Invocation commands By default HP WDB runs in line mode To run it with a terminal user interface similar to that of XDB use the tui option The following table lists the XDB and the equivalent WDB commands for invoking the terminal user interface Table 16 1 Invocation commands 16 1 2 Window mode commands XDB Command WDB Equivalent Meaning xdb program gdb xdb program gdb xdb Debug program tui program xdb program corefile gdb xdb program c Debug core file corefile xdb d dir gdb xdb d dir Specify alternate directory to search for source files xdb P pid program gdb xdb program pid Attach to running pro gram at invocation xdb i after starting run lt file Specify input to target program xdb o after starting run gt file Specify output from target program The following commands are TUI mode or XDB compatibility mode commands They are available when you invoke WDB by using the tui or xdb or both options Table 16 2 Window mode commands XDB Command WDB Eq
434. y Sometimes the string you need while logically a word may contain parentheses or other characters that GDB normally excludes from its notion of a word To permit word completion to work in this situation you may enclose words in single quote marks in GDB commands The most likely situation where you might need this is in typing the name of a C function This is because C allows function overloading multiple definitions of the same function distinguished by argument type For example when you want to set a breakpoint you may need to distinguish whether you mean the version of name that takes an int parameter name int or the version that takes a float parameter name float To use the word completion facilities in this situation type a single quote at the beginning of the function name This alerts GDB that it may need to consider more information than usual when you press TAB or M to request word completion gdb b bubble M GDB Commands bubble double double bubble int int gdb b bubble In some cases GDB can tell that completing a name requires using quotes When this happens GDB inserts the quote for you while completing as much as it can if you do not type the quote in the first place gdb b bub TAB GDB alters your input line to the following and rings a bell gdb b bubble In general GDB can tell that a quote is needed and inserts it if you have not yet started typing
435. y are passed to the C shell usr bin csh which expands wildcard characters and performs redirection of I O and then to your program On non Unix systems the program is usually invoked directly by GDB which emulates T O redirection via the appropriate system calls and the wildcard characters are expanded by the startup code of the program not by the shell The run command used with no arguments uses the same arguments used by the previous run or those set by the set args command Following commands are used to pass the argument values to your program set args Specify the arguments to be used the next time your program is run If set args has no arguments run executes your program with no arguments Once you have run your program with arguments using set argsbefore thenext runis the only way to run it again without arguments show args Show the arguments to give your program when it is started 4 4 Program Environment The environment consists of a set of environment variables and their values Environment variables conventionally record information such as your user name your home directory your terminal type and your search path for programs to run Usually you set up environment variables with the shell and they are inherited by all the other 4 3 Arguments To Your Program 41 42 programs you run When debugging it can be useful to try running your program with a modified environment without having to start GDB over again
436. y number GDB command The corresponding GDB command is enable display Example N A The display insert Command Synopsis display insert expression Display expression every time the program stops GDB command The corresponding GDB command is display Example N A The display list command Synopsis display list List the displays Do not show the current values GDB command The corresponding GDB command is info display Example N A The environment cd command Synopsis environment cd pathdir 328 The GDB MI Interface Set the GDB working directory GDB command The corresponding GDB command is cd Example gdb environment cd kwikemart marge ezannoni flathead dev devo gdb done gdb The environment directory command Synopsis environment directory pathdir Add directory pathdir to the beginning of search path for source files GDB command The corresponding GDB command is dir Example gdb environment directory kwikemart marge ezannoni flathead dev devo gdb done gdb The environment path command Synopsis environment path pathdir Add directories pathdir to beginning of search path for object files GDB command The corresponding GDB command is path Example gdb environment path kwikemart marge ezannoni flathead dev ppc eabi gdb done gdb 21 6 GDB MI Data manipulation 329 The environment pwd command Syn
437. y support Reading symbols from opt javal 4 bin IA64N java no debugging symbols found done Attaching to program opt javal 4 bin IA64N java process 23989 no debugging symbols found Reading symbols from usr lib hpux32 libpthread so 1 no debugging symbols found done Reading symbols from usr lib hpux32 libdl so 1 A NOTE If the version of gdb on the system is older than version 4 5 it will be necessary to specify the full path of the Java executable in order to use the gdb subcommands For example gdb opt javal 4 bin PA_RISC2 0 java p 23989 14 25 2 Enhanced support for C templates This version of HP WDB includes these features to support C templates e Setting breakpoints in template class functions and template functions without having to specify details about the instantiation e The ptype command shows any one of the class instantiations A option v in ptype command will now display the field offset and size information of a struct union class in addition to the default type information Syntax gdb ptype v struct info type struct info off 0 bits len 512 bits int i off 0 bits len 32 bits char a 20 off 32 bits len 160 bits struct details d off 192 bits len 256 bits int b 2 off 448 bits len 2 bits int c 3 off 450 bits len 3 bits lt filler gt 14 25 Language support 221 off 453 bits len 27 b
438. ymbols at the time of the shl_load call See Breakpoints page 51 for more information info share info Print the names of the shared libraries which are sharedlibrary currently loaded sharedlibrary regex share Load shared object library symbols for files matching a regex Unix regular expression As with files loaded automatically it only loads shared libraries required by your program for a core file or after typing run If regex is omitted all shared libraries required by your program are loaded On HP UX systems GDB detects the loading of a shared library and automatically reads in symbols from the newly loaded library up to a threshold that is initially set but that you can modify if you wish Beyond that threshold symbols from shared libraries must be explicitly loaded To load these symbols use the command sharedlibrary filename The base address of the shared library is determined automatically by GDB and need not be specified To display or set the threshold use the commands set auto solib add Set the autoloading size threshold in megabytes threshold If threshold is nonzero symbols from all shared object libraries will be loaded automatically when the inferior begins execution or when the dynamic linker informs GDB that a new library has been loaded until the symbol table of the program and libraries exceeds this threshold Otherwise symbols must be loaded manually using the sharedlibrary command The def
439. you called configure or one of its subdirectories The Makefile that configure generates in each source directory also runs recursively If you type make in a source directory such as gdb gdb 199991101 or in a separate configured directory configured with srcdir dirname gdb gdb 199991101 you will build all the required libraries and then build GDB When you have multiple hosts or targets configured in separate directories you can run make on them in parallel for example if they are NFS mounted on each of the hosts they will not interfere with each other A 2 Specifying names for hosts and targets The specifications used for hosts and targets in the configure script are based on a three part naming scheme but some short predefined aliases are also supported The full naming scheme encodes three pieces of information in the following pattern architecture vendor os For example you can use the alias sun4 as a host argument or as the value for target ina target target option The equivalent full name is sparc sun sunos4 The configure script accompanying GDB does not provide any query facility to list all supported host and target names or aliases conf igure calls the Bourne shell script config sub to map abbreviations to full names you can read the script if you wish or you can use it to test your guesses on abbreviations for example A 2 Specifying names for hosts and targets 367 sh config sub i1386 linux i386 p
440. ype o o Expression in octal as integer O 1 o Expression in octal as long integer P a Print name of procedure containing address s No equivalent String S No equivalent Formatted structure display t whatis ptype Show type of the expression T 1 ptype Show type of expression including base class information u u Expression in unsigned decimal format U 1 u Expression in long unsigned decimal format w No equivalent Wide character string W 1 No equivalent Address of wide character string X x Print in hexadecimal X 1 x Print in long hexadecimal 16 3 XDB data formats and HP WDB equivalents 267 Table 16 16 Data format commands continued XDB Command WDB Equivalent Meaning o O Print in binary Print in long binary 1 HP WDB will display data in the size appropriate for the data It will not extend the length displayed in response to one of the uppercase formchars for example O D F 16 4 XDB location syntax and HP WDB equivalents The following command lists the XDB and the equivalent WDB commands for locating source lines Table 16 17 Macro facility commands XDB location syntax WDB Equivalent Meaning line line Source line and code address file line file line Source line and code address proc proc Procedure name file proc proc line No equivalent Source line and code address file proc proc label No equivalent Sourc
441. ze to fill the value as sizeof value sizeof type gdb p x short 0x12345678 2 0x1234 0x5678 Sometimes the artificial array mechanism is not quite enough in moderately complex data structures the elements of interest may not actually be adjacent for example if you are interested in the values of pointers in an array One useful work around in this situation is to use a convenience variable See Convenience variables page 96 as a counter in an expression that prints the first interesting value and then repeat that expression via RET For instance suppose you have an array dtab of pointers to structures and you are interested in the values of a field fv in each structure Here is an example of what you might type set i 0 p dtab i gt fv lt RET gt lt RET gt 8 4 Output formats 86 By default GDB prints a value according to its data type Sometimes this is not what you want For example you might want to print a number in hex or a pointer in decimal Or you might want to view data in memory at a certain address as a character string or as an instruction To do these things specify an output format when you print a value The simplest use of output formats is to say how to print a value already computed This is done by starting the arguments of the print command witha slash and a format letter The format letters supported are x Regard the bits of the value as an integer and print th

HP gnu source-level debugger 5992-4701 User's Manual

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