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HP Pascal for OpenVMS User Manual

1. value_expr amp statement list END BEGIN Q FOR INDEX 1 TO MAX DO ARR INDEX 0 statement list END Q As you begin the executable section of your program the cursor rests on the placeholder statement_list Type the token FOR over this placeholder and expand FOR Programming Tools 4 5 LSE provides the FOR statement template Select a FOR variable option from the menu Expand the iteration_clause placeholder and expand the statement placeholder LSE displays a menu from which you can select the simple_statement option A further menu appears from which you select the ASSIGNMENT statement option LSE provides the assignment statement template Type an appropriate identifer or value expression over each placeholder Q The completed FOR statement appears in your buffer Example 4 2 shows some contexts in which LSE placeholders and design comments might appear in the design of an HP Pascal program Placeholder contexts are self explanatory the callout numbers identify types of comments which are detailed in the notes following the example Example 4 2 Using LSE Comments in Program Design OpenVMS VAX systems PROGRAM Semester Grades input output o0 Author P Knox Creation Date 03 03 89 Functional Description This program calculates the numerical semester grade and determines the corresponding alphabetic grade for each student in a class
2. Mechargs 13 Not available Mechargs 2 Mechargs 3 Mechargs 4 frame that established the handler The previous stack pointer for the frame that established the handler The number of calls that have been made that is the stack frame depth from the routine activation up to the point at which the condition was signaled The value of register RO R8 on OpenVMS I64 at the time of the signal The value of register R1 R9 on OpenVMS I64 at the time of the signal For a complete description of the mechanism array see the HP OpenVMS Calling Standard 8 3 3 Handler Function Return Values Condition handlers are functions that return values to control subsequent execution These values and their effects are listed as follows Value Effect SS CONTINUE SS RESIGNAL Continues execution from the signal If the signal was issued by a call to LIB STOP the program does not continue but exits Resignals to continue the search for a condition handler to process the condition In addition a condition handler can request a stack unwind by calling the UNWIND system service routine You can inherit UNWIND from SYS LIBRARY STARLET PEN Error Processing and Condition Handling 8 7 When UNWIND is called the function return value of the condition handler is ignored The handler modifies the saved registers RO and R1 in the mechanism parameters to specify the called function s return value
3. Nonlocal References None Included Files None m Keywords Grade array procedures semester grade file CONST number of students compile time exp number of semester grades compile time exp TYPE grade array ARRAY 1 number of semester grades OF integer or real determine later grade range 0 100 continued on next page 4 6 Programming Tools Example 4 2 Cont Using LSE Comments in Program Design OpenVMS VAX systems var A Grade Array grade array var for array of grades A Grade grade range var for individual grade Total grade range var for semester grade variable INTEGER control var FOR loops PROCEDURE compute semester grade VAR Grd_Arry grade array VAR Sum grade range e Parameters Grd Arry value parameter array of semester grades for one student Sum variable parameter returns the semester grade BEGIN FOR control var iteration_clause DO sum the grades in Grd Arry Sum gets Sum divided by number of grades in array write student s semester grade END PROCEDURE assign letter grade Semester Grade grade range BEGIN CASE case_selector OF case labels statement 1case labels i statement s case_labels statementj s case_labels s statement j OTHERWISE statement_list END END
4. continued on next page Programming Tools 4 7 Example 4 2 Cont Using LSE Comments in Program Design OpenVMS VAX systems BEGIN FOR number of students DO BEGIN enter semester grades for student FOR control var value_expr TO number of semester grades DO BEGIN read grades and load into array END Total 0 compute routine Grade Array Total assign letter routine Total END END Q These comments which could be placed at the beginning of the program are tagged comments The comment begins with a predefined term called a tag The tag is followed by a tag terminator symbol and free text These comments which do not contain tags are called remark comments A remark comment consists of free text This structured comment contains both a tag the identifier parameters and subtags the identifiers Grd_Arry and Sum A tag terminator and a blank comment line separate the two subtags from each other 4 3 Accessing CDD Repository from HP Pascal The Oracle CDD Repository CDD Repository must be purchased separately The CDD Repository allows language independent structure declarations that can be shared by many OpenVMS layered products HP Pascal support of the CDD Repository allows HP Pascal programmers to share common record and data definitions with other Hewlett Packard languages and data management products A system manager or data administrator creates the CDD
5. 7 1 Environment I O Support HP Pascal uses the Record Management Services RMS to perform I O tasks at the system level In this environment all of the HP Pascal I O model is supported the model is based on RMS concepts If these sections contain no information on a concept or element in the HP Pascal I O model then this environment supports the concept or element exactly as it is described in the HP Pascal for OpenVMS Language Reference Manual You can use RMS features through HP Pascal when you call the OPEN procedure For instance when you call this procedure you can specify the file organization the component format and the access method If you choose to use additional features of RMS that are not available in the HP Pascal I O model you can write a user action function that manipulates the RMS control blocks the file access block FAB the record access block RAB and the extended attribute block XAB Once you write the user action function you pass the function name as a parameter to the OPEN procedure For More Information e On user action functions Section 7 2 e On OPEN defaults Section 7 1 6 1 e On OPEN and the HP Pascal I O model HP Pascal for OpenVMS Language Reference Manual Input and Output Processing 7 1 On RMS concepts Guide to OpenVMS File Applications e On the user interface to RMS OpenVMS Record Management Services Reference Manual 7 1 1 Indexed Files The HP Pascal I O model allow
6. A stack unwind is usually made to one of two places e The point in the establisher at which the call was made that resulted in the exception Specify the following Status SUNWIND Mechargs 2 0 OpenVMS VAX Status SUNWIND Mechargs 4 0 OpenVMS I64 OpenVMS Alpha e The routine that called the establisher Specify the following Status Status SUNWIND Mechargs 2 1 0 OpenVMS VAX SUNWIND Mechargs 4 1 0 OpenVMS 164 OpenVMS Alpha 8 3 4 Condition Values and Symbols The OpenVMS system uses condition values to indicate that a called routine has either executed successfully or failed and to report exception conditions Condition values are usually symbolic names that represent 32 bit packed records consisting of fields usually interpreted as integers that indicate which system component generated the value the reason the value was generated and the severity of the condition A warning severity code 0 indicates that although output was produced the results may be unpredictable An error severity code 2 indicates that output was produced even though an error was detected Execution can continue but the results may not be correct A severe error code 4 indicates that the error was of such severity that no output was produced A condition handler can alter the severity code of a condition value to allow execution to continue or to force an exit depending on the circumstances Oc
7. BOOLOPREQ BOOLEAN operand s required Error The operation being performed requires operands of type BOOLEAN Such operations include the AND OR and NOT operators and the SET INTERLOCKED and CLEAR INTERLOCKED functions BOOSETREQ BOOLEAN or SET operand s required Error BYTEALIGN Type larger than 32 bits can be positioned only on a byte boundary Error See the HP Pascal for OpenVMS Language Reference Manual for information on the types that are allocated more than 32 bits CALLFUNC Function function name called as procedure function value discarded Warning CARCONMNGLS CARRIAGE CONTROL parameter is meaningless given files type Warning The carriage control parameter is usually meaningful only for files of type TEXT and VARYING OF CHAR CASLABEXPR Case label and case selector expressions are not compatible Error All case labels in a CASE statement must be compatible with the expression specified as the case selector Diagnostic Messages C 7 CASORDRELPTR Compile time cast allowed only between ordinal real and pointer types CASSELORD Case selector expression must be an ordinal type Error CASSRCSIZ Source type of a cast must have a size known at compile time CASTARSIZ Target type of a cast must have a size known at compile time Error A variable being cast by the type cast operator cannot be a conformant array or a conformant VARYING parameter An expression being cast cannot be a conformant ar
8. On RFA Guide to OpenVMS File Applications 7 1 6 OPEN Procedure When you use the OPEN procedure RMS applies default values for OpenVMS file specifications and assigns values to FAB RAB XAB and Name Block data structures Input and Output Processing 7 3 7 1 6 1 OPEN Defaults 7 4 When you use OPEN to open a file RMS applies certain defaults when attempting to locate the physical file Table 7 1 presents these defaults Table 7 1 Default Values for OpenVMS File Specifications Element Default Node Local computer Device Current user device Directory Current user directory File name HP Pascal file variable name or its logical name translation File type DAT Version number history OLD highest current number NEW highest current number 1 The OPEN procedure includes a default file name parameter Using this parameter you can access the RMS default file name parameter to set file specification defaults Consider the following example VAR My File VARYING 20 OF CHAR My File Var TEXT BEGIN My File foo bar OPEN FILE NAME My File FILE VARIABLE My File Var DEFAULT another dir The OPEN statement in the previous example opens the file called ANOTHER DIR FOO BAR RMS applies the defaults in Table 7 1 to determine the node the device and the version number of the file For More Information e On file specifications OpenVMS User s Manual e On the OPEN procedu
9. PACKED RECORD NAME PACKED ARRAY 1 30 OF CHAR ADDRESS PACKED ARRAY 1 40 OF CHAR SALESMAN ID BYTE 5 RECORD END numeric string unsigned END record salesman END record payroll record The option LIST or NOLIST overrides the qualifier SHOWZNODICTIONARY or SHOW DICTIONARY For More Information On CDD Repository CDD Repository CDO Reference Manual Using CDD Repository on VMS Systems and CDD Administrator User s Guide e On the HP Pascal DICTIONARY directive HP Pascal for OpenVMS Language Reference Manual Programming Tools 4 9 4 3 1 Equivalent HP Pascal and CDDL Data Types The CDD Repository supports some data types that are not native to HP Pascal If a data definition contains a field declared with an unsupported data type HP Pascal replaces the field with one declared as a BYTE n RECORD END where n is the appropriate length in bytes By making the data addressable in this way you are able to manipulate the data either by passing it to external routines as variables or by using the HP Pascal type casting capabilities to perform an assignment However because these empty records do not have fields the size of the record is 0 bits They should not be used in expressions or passed to formal value parameters Recall that a size attribute used on a type definition has no effect on fetches When fetching from these records the compiler will fetch the actual size of the record
10. STDINCLUDE Nonstandard INCLUDE directive STDINITVAR Nonstandard initialization syntax in VAR section Information These messages refer to extensions to Pascal and are issued only if you have specified the standard switch on the compile command line STDKEYWRD Nonstandard keyword name Information This message is issued if you have specified a standard option other than extended on the compile command line STDMATCHVRNT Nonstandard no matching variant label Information This message is issued if you call the NEW or DISPOSE procedure and one of the case labels specified in the call does not correspond to a case label in the record variable You must also have specified the standard switch on the compile command line STDMODCTL Nonstandard potential uplevel modification of variable name prohibits use as control variable Information You cannot use as the control variable of a FOR statement any variable that might be modified in a nested block This message is issued only if you have specified the standard switch on the compile command line C 50 Diagnostic Messages STDMODULE Nonstandard MODULE declaration Information The item listed in this message is an extension to Pascal This message is issued only if you have specified the standard switch on the compile command line STDNILCON Nonstandard use of reserved word NIL as a constant Information Only simple constants and quoted strings are allowed by th
11. Specifies a list of items to be displayed on the terminal A single identifier or a list of identifiers enclosed in parentheses can follow the TERMINAL qualifier these identifiers are options that inform the compiler which type of information to display Table 1 12 lists the available options their corresponding actions and their negations Table 1 12 TERMINAL Qualifier Options Option Action Negation ALL Displays all options NONE FILE NAME Displays file names on Pascal NOFILE NAME command line as they are being processed ROUTINE NAME Displays routine names as code NOROUTINE NAME OpenVMS VAX is generated systems only STATISTICS Displays compiler statistics NOSTATISTICS The TERMINAL qualifier without options is equivalent to TERMINAL ALL The negation NOTERMINAL is equivalent to TERMINAL NONE NO TIE OpenVMS Alpha systems only NOTIE default Specifies that the generated code can call images translated by the VAX Environment Software Translator VEST utility which translates OpenVMS VAX system images into functionally equivalent OpenVMS Alpha system images The Translated Image Environment TIE allows translated images to execute as if on an OpenVMS VAX system Compiling HP Pascal Programs 1 21 NOJUSAGE USAGE EMPTY RECORDS NONGRNACC PACKED ACTUALS UNSUPPORTED CDD UNINITIALIZED VOLATILE defaults Directs the compiler to perform compile time checks indicated by the chosen option
12. CSTRREFALRG Repetition factor too large CSTRREFANEG Repetition factor cannot be negative CSTRTOOMANY Constructor too many components Error You can write constructors only for data items of an ARRAY type You must specify one and only one value in the constructor for each component of the type In an array constructor you cannot use a negative integer value as a repetition factor to specify values for consecutive components CSTRREFAINT Repetition factor must be an integer Error CTESTRSIZ Compile time strings must be less than 8192 characters Error CTGARRDESC Contiguous array descriptor cannot describe size alignment properties Information Conformant array parameters dynamic array parameters and DESCR array parameters all use the contiguous array descriptor mechanism in the HP OpenVMS Calling Standard Size and alignment attributes are prohibited on such arrays as these attributes can create noncontiguous allocation This message can appear as additional information in other error messages DEBUGOPT NOOPTIMIZE is recommended with DEBUG Information Unexpected results may be seen when debugging an optimized program To prevent conflicts between optimization and debugging you should compile your program with NOOPTIMIZE until it is thoroughly debugged Then you can recompile the program with optimization enabled to produce more efficient code DECLORDER Declarations are out of order Error The TO BEGIN DO a
13. DIREXPECT No matching directive for the IF directive Error A IF directive must contain a THEN clause and be terminated by ENDIF DIRUNEXP Error Conditional compilation directives other than IF are only valid after the parts of a IF directive Diagnostic Messages C 15 DISCLIMIT Limit of 255 discriminants exceeded Error DISNOTORD Discriminant type must be an ordinal type Error The formal discriminant in a schema type definition must be an ordinal type DONTPACKVAR routine name is illegal variable can never appear in a packed context Error You cannot call the BITSIZE and BITNEXT functions for conformant parameters DUPLALIGN Alignment already specified DUPLALLOC Allocation already specified DUPLATTR Attribute already specified DUPLCLASS Descriptor class already specified DUPLDOUBLE Double precision already specified Error Only one member of a particular attribute class can appear in the same attribute list DUPLFIN TO END DO already specified DUPLINIT TO BEGIN DO already specified Error Only one TO BEGIN DO and one TO END DO section can appear in the same module DUPLGBLNAM Duplicated global name Warning The GLOBAL attribute cannot appear on more than one variable or routine with the same name DUPLMECH Passing mechanism already specified DUPLOPT Optimization already specified DUPLSIZE Size already specified DUPLVISIB Visibility already specified Error Only one member of
14. Specifies that the input file is an object module or shareable image library which the linker must search to resolve undefined symbols within other input modules specified on the same command line You can use the LIBRARY qualifier with the INCLUDE qualifier to modify the same input file specification In that case the same library is searched for unresolved references This qualifier is a file qualifier and cannot be used directly on the LINK command The default for the file to which this qualifier is applied is the OLB file type NO MAP NOMAP interactive default MAP NOCROSS REFERENCE batch default Controls the generation of a map file and its contents The MAP qualifier produces a map file which you can name by including a file specification The map file is stored on the default device in the default directory If you do not include a file specification with MAP the map file is given the name of the first input file and a MAP file type With the MAP qualifier you can use the qualifiers BRIEF FULL and CROSS REFERENCE to define the type of information included in the map file 1 34 Compiling HP Pascal Programs filename OPTIONS none default Specifies that the input file is a linker options file which can contain input file specifications as well as special instructions recognized only by the linker You can also use options files to create shareable images NOJSHAREABLE NOSHAREABLE default
15. 3 1 6 Inline Code Expansion for User Declared Routines Inline code expansion for user declared routines performs in the same manner as inline code expansion for predeclared functions the compiler can often replace calls to user declared routines with an inline expansion of the routine s executable code Inline code expansion is useful on routines that are called only a few times The overhead of an actual procedure call is avoided which increases program execution The size of the program however may increase due to the routine s expansion To determine whether or not it is desirable to inline expand a routine compilers use a complex algorithm Section 3 1 7 describes the algorithm for HP Pascal on OpenVMS VAX systems HP Pascal on OpenVMS 164 and OpenVMS Alpha systems uses a similar algorithm to make the determination 3 1 7 Testing for Inline Expansion on OpenVMS VAX Systems The first part of the algorithm performs tests for cases that always prohibit the routine from being inlined A failure of one of these tests can be thought of as a hard failure These hard failure tests verify that the following are false if any one of these tests is true the routine is not inlined e The called routine is an external or inherited routine e Hither the calling routine or the called routine does not have inlining optimization enabled Note that optimization is enabled by default e The called routine establishes an exception handler or is
16. CIRCLE Code that draws a rectangle Scaling the shape RECTANGLE Rotating the shape RECTANGLE Deleting the shape RECTANGLE Separate Compilation 2 19 3 Program Correctness Optimization and Efficiency This chapter discusses the following topics e Section 3 1 Compiler Optimizations e Section 3 2 Programming Considerations e Section 3 3 Implementation Dependent Behavior The objective of optimization is to produce source and object programs that achieve the greatest amount of processing with the least amount of time and memory Realizing this objective requires programs that are carefully designed and written and compilation techniques such as those used by HP Pascal that take advantage of the operating system and machine architecture environment The benefits of portable code and program efficiency depend on the requirements of your application 3 1 Compiler Optimizations By default programs compiled with the HP Pascal compiler undergo optimization An optimizing compiler automatically attempts to remove repetitious instructions and redundant computations by making assumptions about the values of certain variables This in turn reduces the size of the object code allowing a program written in a high level language to execute at a speed comparable to that of a well written assembly language program Optimization can increase the amount of time required to compile a program but the result is a program that may
17. CNFREQNCA Conformants of this parameter type require CLASS_NCA Error The conformant parameter cannot be described with the default CLASS_A descriptor Add the CLASS_NCA attribute to the parameter declaration CNSTRNOTALL Nonstandard constructors are not allowed on nonstatic types Error You can write constructors for nonstatic types using the standard style of constructor CNSTRONZERO Record constructors only allow OTHERWISE ZERO Error Diagnostic Messages C 11 CNTBEARRCMP Not allowed on an array component CNTBEARRIDX Not allowed on an array index CNTBECAST Not allowed on a cast CNTBECNFCMP Not allowed on a conformant array component CNTBECNFIDX Not allowed on a conformant array index CNTBECNFVRY Not allowed on a conformant varying component CNTBECOMP Not allowed on a compilation unit CNTBECONST Not allowed on a CONST definition part CNTBEDEFDECL Not allowed on any definition or declaration part CNTBEDESPARM Not allowed on a DESCR foreign mechanism parameter CNTBEEXESEC Not allowed on an executable section CNTBEFILCMP Not allowed on a file component CNTBEFORMAL Not allowed on a formal discriminant CNTBEFUNC Not allowed on a function result CNTBEIMMPARM Not allowed on a parameter passed by an immediate passing mechanism CNTBELABEL Not allowed on a LABEL declaration part CNTBEPCKCNF Not allowed on a PACKED conformant array component CNTBEPTRBAS Not allowed on a pointer base CNTBERECFLD Not al
18. LSE SCA support of HP Pascal 4 2 to 4 4 M Machine code section in listing file 1 27 MACHINE CODE qualifier 1 15 Map file 1 34 MAP qualifier with LINK command 1 34 MATH LIBRARY qualifier 1 15 MAXINT64 predeclared constant 3 17 MAXINT predeclared constant 3 17 Mechanism array 8 6 Mechanism specifier DESCR 5 14 STDESCR 5 13 Messages compiler C 1 to C 65 run time C 65 to C 86 syntax of 1 38 Methods to obtain access methods 6 6 to obtain OpenVMS data types 6 6 Migrate bound procedure values 9 2 default data layout 9 2 INT 9 2 Migrating HP Pascal programs OpenVMS VAX to OpenVMS I64 or OpenVMS Alpha 9 1 Module 2 1 finalization section 2 15 implementations and interfaces 2 7 restrictions 2 10 initialization and finalization sections restrictions 2 10 Module cont d initialization section 2 15 interface inheritance path figure 2 7 multiply declared identifiers 2 4 relinking implementation modules 2 9 requirements for linking modules 2 2 TO BEGIN DO section 2 12 MTHDEF PAS definition file 6 3 MULTILANGUAGE qualifier 1 18 N Name block fields when calling OPEN 7 9 NOACCURACY_SENSITIVE 1 7 Nonstatic type restriction in modules 2 10 NOOPTIMIZE qualifier 1 18 effect on debugging 1 11 O Object file 1 16 Object module library 1 36 symbol table in 1 36 OBJECT qualifier 1 16 OPEN procedure default for VMS files 7 4 related to RMS data stru
19. Portions of the message text enclosed in quotation marks are items that the compiler substitutes with the name of a data object when it generates the message 64BITBASTYP 64 bit pointer base types cannot contain file variables ERROR File types may not be allocated in 64 bit P2 address space because their implementation currently assumes 32 bit pointers in internal data structures 64BITNOTALL 64 bit pointers are not allowed in this context ERROR File types may not be allocated in 64 bit P2 address space because their implementation currently assumes 32 bit pointers in internal data structures ABSALIGNCON Absolute address alignment conflict Error The address specified by the AT attribute does not have the number of low order bits implied by the specified alignment attribute ACCMETHCON Specified ACCESS_METHOD conflicts with file s record organization Warning You cannot specify ACCESS_METHOD DIRECT for a file that has indexed organization or sequential organization and variable length records You cannot specify ACCESS_METHOD KEYED for a file with sequential or relative organization ACTHASNOFRML Actual parameter has no corresponding formal parameter Error The number of actual parameters specified in a routine call exceeds the number of formal parameters in the routine s declaration and the last formal parameter does not have the LIST attribute ACTMULTPL Actual parameter specified more than once Error E
20. READONLY 1 if SHARING READWRITE 1 if SHARING READWRITE 1 if SHARING NONE default if HISTORY is not READONLY You cannot change XABs provided by Hewlett Packard but you can add and delete XABs that you insert using a user action function Table 7 3 presents the status of RMS RAB fields when you call the OPEN procedure If a field is not included in the following table it is initialized to Zero Input and Output Processing 7 7 Table 7 3 Setting of RMS Record Access Block Fields by a Call to the OPEN Procedure Field Name OPEN Parameters and Value RAB L CTX Context Reserved to Hewlett Packard RAB L FAB FAB address Set to address of FAB allocated by HP Pascal RTL RAB W ISI Internal stream identifier Returned by RMS RAB L KBF Key buffer address May be modified for individual file operations after the file is opened RAB B KRF Key of reference May be modified for individual file operations after the file is opened RAB B KSZ Key size May be modified for individual file operations after the file is opened RAB B RAC Record access mode May be modified for individual file operations after the file is opened RAB L RBF Record address May be modified for individual file operations after the file is opened RAB L RHB Record header buffer Set to address of 2 byte carriage control information for terminal files enabled for prompting RAB L ROP Record options RAB V NLK No lock May be modified for indivi
21. REF STDESCR and DESCR on an actual parameter For example the following is an example of calling lib get_vm_64 using ref to override the definition from PASCAL LIB_ROUTINES PEN inherit sys library pascal lib routines program p64 input output const arr size 8192 10 div 4 Make each array be 10 pages type arr array 1 arr size of integer arrptr quad arr ptr arrptr ptrarr array 1 10 of arrptr i j stat integer sum integer64 Programming on OpenVMS Systems 6 19 PASCALSLIB ROUTINES PAS on a V7 1 system contains the following definitions for LIBSGET VM 64 type SQUAD QUAD UNSAFE RECORD L0 UNSIGNED L1 INTEGER END SUQUAD QUAD UNSAFE RECORD LO L1 UNSIGNED END lib routines typ4 QUAD number of bytes SQUAD VAR base address VOLATILE lib routines typ4 zone id SUQUAD IMMED 0 INTEGER EXTERNAL l l l l ASYNCHRONOUS FUNCTION lib get vm 64 I Note that the BASE ADDRESS parameter is a 64 bit pointer that will be returned by LIBSGET VM 64 The definition incorrectly declared it as a pointer to a record that is quadword sized begin Allocate memory with lib get vm 64 The definition of lib get vm 64 declares the return address parameter as a quadword sized record since it doesn t have sufficient information to generate a INTEGER64 or other type l l Use an expl
22. STDSUBSTRING Nonstandard Substring notation Information STDZERO Nonstandard ZERO function used in constructor Information This message refers to an extension in Pascal and is issued only if you have specified the standard switch on the compile command line STOREQEXC Allocations to Psect name exceeded growth bounds Error Too much data is allocated to the Psect Either place variables into different Psects or break up the program into multiple modules Diagnostic Messages C 55 STREQLLEN String values must be of equal length Error You cannot perform string comparisons on character strings that have different lengths STROPNDREQ String CHAR PACKED ARRAY 1 n OF CHAR or VARYING operand required STRPARMREQ String CHAR PACKED ARRAY 1 n OF CHAR or VARYING parameter required STRTYPREQ String CHAR PACKED ARRAY 1 n OF CHAR or VARYING type required Error The file name parameter to the OPEN procedure and the parameter to the LENGTH function must be character strings of the types listed SYNASCII Illegal ASCII character SYNASSERP Syntax 5 or expected SYNASSIGN Syntax expected SYNASSIN Syntax or IN expected SYNASSSEMI Syntax or 5 expected SYNATRCAST Syntax attribute list not allowed on a type cast SYNATTTYPE Syntax attribute list or type specification SYNBEGDECL Syntax BEGIN or declaration expected SYNBEGEND Syntax BEGIN or END expected SYN
23. This example shows a handler that records the condition status if a floating overflow or underflow error is detected during the execution of the mathematical function MTH EXP Example 7 INHERIT SYSSLIBRARY STARLET PROGRAM Use A Handler INPUT OUTPUT TYPE Sigarr ARRAY 0 9 OF INTEGER Mecharr ARRAY 0 Size CHF2STYPE 4 DIV 4 OF INTEGER VAR F1 F2 REAL ASYNCHRONOUS FUNCTION My Handler VAR Sigargs Sigarr VAR Mechargs Mecharr INTEGER VAR Outfile TEXT ASYNCHRONOUS FUNCTION LIBS FIXUP FLT VAR Sigargs Sigarr VAR Mechargs Mecharr New Opnd REAL IMMED 0 INTEGER EXTERNAL Lu ASYNCHRONOUS FUNCTION LIBSSIM_ TRAP VAR Sigargs Sigarr VAR Mechargs Mecharr INTEGER EXTERNAL BEGIN OPEN Outfile TT REWRITE Outfile Handle various conditions CASE Sigargs 1 OF Convert floating faults to traps SS FLTDIV F SS FLTOVF F LIB SIM TRAP Sigargs Mechargs Handle the floating divide by zero trap SS _FLTDIV BEGIN WRITELN Outfile Floating divide by zero My Handler SS CONTINUE END Handle the floating overflow trap SS _FLTOVF i BEGIN WRITELN Outfile Floating overflow My Handler SS CONTINUE END Error Processing and Condition Handling 8 15 BEGIN Pd F2 Fl Fl Fl END Handle taking the square root MTHS SQUROONEG BEGIN WRITELN Outfile Square root of a negative num
24. e The length of the file components was greater than that allowed for the file organization and record format for most operations the largest length allowed is 32 765 bytes The value of the RECORD LENGTH parameter to the OPEN procedure was greater than that allowed for the file organization and record format for most operations the largest value allowed is 32 765 bytes User Action Correct the program so that the record length used is within the permitted limits for the type of file being used See the OpenVMS Record Management Services Reference Manual for more information Diagnostic Messages C 77 INVSYNBIN string is invalid syntax for a binary value Explanation While a READ or READV procedure was reading a binary value from a text file the characters read did not conform to the syntax for a binary value The displayed message includes the text actually read and the record number in which this text occurred User Action Correct the program or the input data so that the correct syntax is used See the HP Pascal for OpenVMS Language Reference Manual for more information INVSYNHEX string is invalid syntax for a hexadecimal value Explanation While a READ or READV procedure was reading a hexadecimal value from a text file the characters read did not conform to the syntax for an hexadecimal value The displayed message includes the text actually read and the record number in which this text occurred User Action Corre
25. procedure rtn p immediate integer external begin rtn 3 rtn some integer expression end If you want to pass a parameter with the by descriptor mechanism you can place the CLASS A CLASS S or CLASS_NCA attributes on the formal parameter s definition You can also use the DESCR and STDESCR foreign mechanism specifiers but be aware that these also imply parameter semantics as well as the parameter passing mechanism When passing values to a subrange parameter in a Pascal routine the argument must be large enough to hold a value of the subrange s base type even if the formal parameter contained a size attribute When passing Boolean or enumerated type values to a VAR parameter in a Pascal routine the calling routine must ensure that the sizes of the Boolean or enumerated type matches the setting of the ENUMERATION SIZE qualifier or ENUMERATION SIZE attribute used in the Pascal routine For value parameters you can pass the address of a longword as that will work for either setting When passing arrays or records to a Pascal routine the calling routine must ensure that the array and record has the same layout including any alignment holes as chosen by the HP Pascal compiler You may want to use the SHOWZSTRUCTURE LAYOUT listing section to help you determine the layout chosen by the HP Pascal compiler By default HP Pascal will use the by descriptor mechanism for VAR and value conformant par
26. the value in the register may be used instead of the changed value in the expression causing unexpected results When the value of a variable is being held in a register its value in memory is generally invalid therefore a spurious value may be displayed if you try to examine a variable under these circumstances Coding order Some of the compiler optimizations cause code to be generated in a order different from the way it appears in the source Sometimes code is eliminated altogether This causes unexpected behavior when you try to step by line use source display features or examine or deposit variables Use of condition codes OpenVMS VAX systems This optimization technique takes advantage of the way in which the VAX processor condition codes are set For example consider the following source code X X 4 92 5 IF x lt 0 THEN Rather than test the new value of x to determine whether to branch the optimized object code bases its decision on the condition code settings after 2 5 is added to x If you attempt to set a debugging breakpoint at the second line and deposit a different value into x you cannot achieve the intended result because the condition codes no longer reflect the value of x Program Correctness Optimization and Efficiency 3 21 In other words the decision to branch is being made without regard to the deposited value of the variable e Inline code expansion on user declared routines There is no
27. value in value parameter describes the semantics of the parameter where changes made to the parameter inside the called routine are not reflected back to the actual parameter It is a common misconception that HP Pascal uses the by immediate value mechanism for value parameters 5 4 2 Passing Nonroutine Parameters between HP Pascal and Other Languages By default HP Pascal will use the by reference mechanism for the following VAR and value parameter types Ordinal integer unsigned char Boolean pointers subranges and enumerated types Real real double quadruple Record Array Set Varying and File If you want to pass a parameter with the by immediate value mechanism you can place the IMMEDIATE attribute on the definition of the formal parameter s definition or use the IMMED foreign mechanism specifier on the actual parameter to override the default mechanism of the formal parameter Only ordinal and real types may be passed with the by immediate value mechanism Only value parameters may use the by immediate value mechanism Calling Conventions 5 17 If you want to accept a value parameter with the by immediate value you can place the IMMEDIATE attribute on the definition of the formal parameter Only ordinal and real types may be accepted with the by immediate value mechanism For example to pass an integer with the by immediate value mechanisn to another routine external
28. 0 bits Table 4 3 summarizes the mapping between CDDL data types and the corresponding HP Pascal data types NOTE Although this practice is discouraged you can use both D floating and G floating data types in the same compilation unit however both types cannot be handled in the same expression Not all processors support the G floating and H floating types Table 4 3 Equivalent CDD Repository Language and HP Pascal Data Types CDDL Data Type HP Pascal Data Type Unspecified BYTE n RECORD END Byte logical BYTE 0 255 Word logical WORD 0 65535 Longword logical UNSIGNED Quadword logical BYTE 8 RECORD END Octaword logical BYTE 16 RECORD END Byte integer BYTE 128 127 Word integer WORD 32768 32767 continued on next page 4 10 Programming Tools Table 4 3 Cont Equivalent CDD Repository Language and HP Pascal Data Types CDDL Data Type HP Pascal Data Type Longword integer Quadword integer Octaword integer F floating D floating G floating H floating OpenVMS VAX systems F floating complex D floating complex G floating complex H floating complex Text Varying text Numeric string unsigned Numeric string left separate Numeric string left overpunch Numeric string right separate Numeric string right overpunch Numeric string zoned sign Bit INTEGER BYTE 8 RECORD END BYTE 16 RECORD END SINGLE DOUBLE NOG FLOATING DOU
29. 1 1 4 3 Defining Default Libraries You can define one of your private text libraries as a default text library for the Pascal compiler to search The HP Pascal compiler searches the default library after it searches libraries specified in the PASCAL command To establish a default library define the logical name PASCAL LIBRARY as in the following example of the DEFINE command DEFINE PASCALSLIBRARY DISK LIB DATAB While this assignment is in effect the compiler automatically searches the library DISK LIBIDATAB TLB for any included modules that it cannot locate in libraries explicitly specified on the PASCAL command The HP Pascal compiler uses PASCAL LIBRARY as the file name for the default text library the location and search order of the logical name tables are controlled by Record Management Services RMS If PASCAL LIBRARY is defined as a search list the compiler opens the first item specified in the list If the include module is not found there the search is terminated and an error message is issued For More Information e On the DCL command DEFINE HP OpenVMS DCL Dictionary 1 2 LINK Command The LINK command invokes the OpenVMS Linker which combines object modules into one executable image which can then be executed by the OpenVMS operating system The linker uses the name of the input file that you specified first on the command line for the name of the output file The default for linker output files exec
30. 10 IDENT V1 0 Note that the definition of CONSTANT is such that DCL does not remove any double quote characters used in the name value clauses All characters are literally passed to the compiler for processing This behavior is slightly different from the usual behavior of putting items in double quotes on DCL commands to preserve the case but not to pass the double quotes to the target application This definition of CONSTANT allows you to define Pascal string literals with embedded single quotes and for DCL symbol substitutions For example PASCAL CONSTANT MSG Special compile run for Monday S IDENT V1 0 PASCAL CONSTANT MSG IDENT Inserting double quote characters and inserting adjacent single quote characters can be accomplished by using the escape character allowed in HP Pascal double quoted string constants By using the single quote escape character you can insert adjacent single quotes without DCL interpreting it as a symbol substition as shown in the following example PASCAL CONSTANT MSG String with 2 single quote characters Do not use to insert a double quote character into the string literal as DCL will interpret the double quote as the end of the string Instead use the x22 character literal 16 22 is the ASCII code for the double quote character to insert a double quote character into the string literal without DCL interpreting it as the end of the string This is shown in
31. A Unaligned bit N A string with bounds Parameters passed by reference and used solely as input to a system service should be declared with HP Pascal value semantics this allows actual parameters to be compile time and run time expressions When a system service requires a formal parameter with a mechanism specifier you should declare the formal parameter with the READONLY attribute to specify value 6 8 Programming on OpenVMS Systems semantics Other parameters passed by reference should be declared with HP Pascal variable semantics to ensure that the output data is interpreted correctly In some cases by reference parameters are used for both input and output and should also be declared with variable semantics The following example shows the declaration of the Convert ASCII String to Binary Time SYS BINTIM system service and a corresponding function designator TYPE SQUAD QUAD UNSAFE RECORD LO UNSIGNED L1 INTEGER END VAR Ascii Time VARYING 80 OF CHAR Binary Time SQUAD ASYNCHRONOUS EXTERNAL SYSSBINTIM FUNCTION BINTIM TIMBUF CLASS S PACKED ARRAY 11 u1 INTEGER OF CHAR VAR TIMADR VOLATILE QUAD INTEGER EXTERNAL In the executable section IF NOT ODD SBINTIM Ascii Time Binary Time WRITELN Illegal format for time string The first formal parameter requires the address of a character string descriptor with value semantics the second requires an addres
32. Access Methods 6 2 3 Methods Used to Obtain Passing Mechanisms 6 2 4 Data Structure Parameters llle 6 2 5 Default Parameters 0 0 0 0 cece eee 6 2 6 Arbitrary Length Parameter Lists 04 6 3 Calling System Routines 0 00 6 4 Using Attributes xa tapes exa som Aas epe RD aS eae d 6 5 Using Item Lists lesen 6 6 Using Foreign Mechanism Specifiers on Actual Parameters 6 7 Using 64 Bit Pointer Types 0 0 eee eee eee 6 7 1 Pascal Language Features Not Supported with 64 Bit PONTET c c ONG aw Ge S uer v EROR E E wale 6 7 2 Using 64 Bit Pointers with System Definition Files 7 Input and Output Processing vi 7 1 Environment I O Support 0 0 0 eee 7 1 1 Indexed Ries ad debe ae edd us S RE E 7 1 2 OpenVMS Components and RMS Records 7 1 3 Count Fields for Variable Length Components 7 1 4 Variable Length with Fixed Length Control Field VFC Component Format eee 7 1 5 Random Access by Record File Address RFA 7 1 6 OPEN Procedure cca RR RR RI RR 7 1 6 1 OPEN Defaults 4 322 car ae ee keen n 7 1 6 2 OPEN and RMS Data Structures 0 7 1 7 Default Line Limits 0 0 0 0 0 0 eee ee eee 7 2 User Action Functions 0 00 ccc ee eee 7 3 Pile Shatifig 22 arse de a As EENEN CR c ERR IR 7 4 Record hocking us 2424 pe isya eue UR Ue Eu
33. Calling Conventions 5 13 The following function declaration requires one fixed length string descriptor as a parameter ASYNCHRONOUS EXTERNAL SYSSSETDDIR FUNCTION SSETDDIR SSTDESCR New Dir PACKED ARRAY L1 U1 INTEGER OF CHAR VAR Old Dir Len SUWORD IMMED 0 VAR Old Dir CLASS S PACKED ARRAY L2 U2 INTEGER OF CHAR SIMMED 0 INTEGER EXTERN Status SSETDDIR HP Pascal The actual parameter HP Pascal is passed by string descriptor with foreign semantics to the formal parameter New Dir 5 3 3 4 DESCR Mechanism Specifier When you use the DESCR mechanism specifier the parameter generates a descriptor for an ordinal real or array variable and passes its address to the called routine The type of DESCR parameter can be any ordinal or real type a VARYING OF CHAR string or an array packed or unpacked fixed or conformant of an ordinal or real type The passing semantics depend on the actual parameter s data type as follows e Ifthe actual parameter is a variable the DESCR formal parameter implies variable semantics within the called routine e Ifthe actual parameter is an expression or a variable enclosed in parentheses DESCR implies foreign semantics If the actual parameter is not modified by the called external routine the corresponding formal parameter should be declared READONLY saving the copy from having to be made The following function declaration requires a va
34. Error NCATOA Cannot reformat content of actual s CLASS NCA descriptor as CLASS A Error This message can appear as additional information on other error messages NEWQUADAGN type name s base type is ALIGNED nnn NEW handles at most ALIGNED 3 Error You cannot call the NEW procedure to allocate pointer variables whose base types specify alignment greater than a quadword To allocate such variables you must use external routines NOACTCOM No actuals are compatible with schema formal parameter Information Undiscriminated schema formal parameters denoting subranges or sets cannot be used as value parameters In these cases no actual parameter can ever be compatible with the formal parameter NOASSTOFNC Block does not contain an assignment to function result function name Warning The block of a function must include a statement that assigns a return value to the function identifier NOCONVAL A constant value was not specified for field field name Error NODECLVAR symbol name is not declared in a VAR section of block name Error You cannot initialize a variable using the VALUE section if the variable was not declared in the same block in which the VALUE section appears C 32 Diagnostic Messages NODSCREC No descriptor class for RECORD type Error The HP OpenVMS Calling Standard does not define a descriptor format for records therefore you cannot specify DESCR for a parameter of
35. Error The value n has the value 4 on OpenVMS 164 systems 3 on OpenVMS Alpha systems and 2 on OpenVMS VAX systems The use of an attribute on a parameter conflicts with the requirements of the object s type ALLPRMSAM All parameters to MIN or MAX must have the same type Error APARMACTDEF Anonymous parameter parameter number has neither actual nor default Error If the declaration of a routine failed to specify a name for a formal parameter a call to the routine will result in this error message The routine declaration will also cause an error to be reported ARITHOPNDREQ Arithmetic operand s required Error C 4 Diagnostic Messages ARRCNTPCK Array cannot be PACKED Error At least one parameter to the PACK or UNPACK procedure must be unpacked ARRHAVSIZ routine name requires that ARRAY component have compile time known size Error You cannot use the PACK and UNPACK procedures to pack or unpack one multidimensional conformant array into another The component type of the dimension being copied must have a compile time known size that is it must have some type other than a conformant schema ARRMSTPCK Array must be PACKED Error At least one parameter to the PACK or UNPACK procedure must be of type PACKED ARRNOTSTR Array type is not a string type Error You cannot write a value to a text file using WRITE or WRITELN or to a VARYING string using WRITEV if there is no textual re
36. FAB L NAM must contain the same value it had before the call 7 6 Input and Output Processing continued on next page Table 7 2 Cont Setting of RMS File Access Block Fields by a Call to the OPEN Procedure Field Name OPEN Parameters and Value FAB B_RFM FAB L_SDC FAB L_XAB FAB B_SHR FAB V_SHRPUT FAB V_SHRGET FAB V_SHRDEL FAB V_SHRUPD FAB V NIL Record format Spooling device characteristics Extended attribute block address File sharing Allow other PUTs Allow other GETs Allow other DELETEs Allow other UPDATEs Allow no other operations FAB C FIX if RECORD TYPE FIXED or if file component is of fixed size FAB C VAR if RECORD TYPE VARIABLE or file is VARYING or TEXT FAB C STM if RECORD TYPE STREAM FAB C STMCR if RECORD TYPE STREAM CR FABSC STMLF if RECORD TYPE STREAM LF FAB C VFC if a terminal file enabled for prompting Returned by RMS The XAB chain always has a File Header Characteristics FHC extended attribute block in order to get the longest record length XAB W LRL If ACCESS METHOD KEYED key index definition blocks are also present Hewlett Packard may add additional XABs in the future Your user action function may insert XABs anywhere in the chain This field is only valid during execution of user action functions HP Pascal places 0 in this field after the call to OPEN 1 if SHARING READWRITE 1 if SHARING is not NONE default if HISTORY
37. Floating underflow SS FLTUND F SS FLTUND Floating divide by zero SS FLTDIV F SS FLTDIV To convert faults to traps you can use the run time library LIB SIM TRAP procedure either as a condition handler or as a called routine from a user written handler When LIB SIM TRAP recognizes a floating fault it simulates the instruction completion as if a floating trap had occurred 8 5 Examples of Condition Handlers The examples in this section inherit the UNWIND system service routine from SYS LIBRARY STARLET PEN They also assume the following declaration has been made INHERIT SYSSLIBRARY STARLET SYSSLIBRARY PASCALSLIB ROUTINES PROGRAM Error Handling INPUT OUTPUT TYPE Sig Args ARRAY 0 100 OF INTEGER Signal parameters Mech Args ARRAY 0 SIZE CHF2STYPE 4 DIV 4 OF UNSAFE INTEGER Mechanism parameters Example 1 ASYNCHRONOUS FUNCTION Handler 0 VAR SA Sig Args VAR MA Mech Args UNSAFE INTEGER BEGIN IF LIBSMATCH COND SA 1 condition name enc S50 THEN BEGIN do something appropriate Handler 0 SS CONTINUE condition handled propagate no further END ELSE Handler 0 SS RESIGNAL propagate condition status to other handlers END Error Processing and Condition Handling 8 11 This example shows a simple condition handler The handler identifies the condition being signaled as one that it is prepared to handle and then takes appropriate action Note that
38. PASCAL command 2 2 examples of 1 3 qualifiers with 1 3 to 1 25 specifying text libraries in 1 30 syntax of 1 1 PASDEF PAS definition file 6 3 Passing mechanisms 5 7 by descriptor 5 9 by immediate value 5 8 by reference 5 8 foreign 5 15 summary of 5 15 type translations 6 7 Passing semantics summary of 5 15 PC saved by routine call 5 5 Performance optimal 3 13 Pipelining software 3 12 Placeholder processing 4 3 PLATFORMS qualifier 1 18 Pointer run time checking of 1 7 Pointer types 64 bit 6 17 POS attribute with data structure parameter 6 9 Predeclared function optimization of 3 6 Predeclared routines I O processing 7 1 to 7 16 Procedure calling standard 5 1 Processor selection 3 13 Processor tuning 3 13 Program See also Separate compilation compiling 1 1 linking 1 31 modularity of 2 1 to 2 19 Index 8 Program counter See PC Program exit status definition of 8 2 Propagation value 3 8 Q QUAD on pointer types 6 21 Qualifiers ALIGN 1 3 ANALYSIS DATA 1 4 ARCHITECTURE 1 4 ASSUME 1 7 BRIEF 1 34 CHECK 1 7 CONSTANT 1 8 CROSS REFERENCE 1 10 DEBUG 1 10 1 33 DESIGN 1 11 DIAGNOSTICS 1 12 ENUMERATION SIZE 1 12 ENVIRONMENT 1 13 ERROR LIMIT 1 13 EXECUTABLE 1 34 FLOAT 1 13 FULL 1 34 GRANULARITY 1 14 INCLUDE 1 15 1 34 LIBRARY 1 14 1 34 LIST 1 15 MACHINE CODE 1 15 MAP 1 34 MATH LIBRAR
39. Pascal ASSERT built in routine evaluated to false User Action Correct the problem that was being checked with the ASSERT built in in the source program BUGCHECR internal consistency failure nnn in Pascal Run Time Library Explanation The run time library has detected an internal error or inconsistency This problem may be caused by an out of bounds array reference or a similar error in your program User Action Rerun your program with all CHECK options enabled If you are unable to find an error in your program please submit a Software Performance Report SPR to Hewlett Packard including a machine readable copy of your program data and a sample execution illustrating the problem CANCNTERR handler cannot continue from a nonfile error Explanation A user condition handler attempted to return SS CONTINUE for an error not involving file input output To recover from such an error you must use either an uplevel GOTO statement or the SYS UNWIND system service User Action Modify the user handler to use one of the allowed recovery actions for nonfile errors or to resignal the error if no recovery action is possible CASSELVAL CASE selector value is out of range Explanation The value of the case selector in a CASE statement does not equal any of the specified case labels and the statement has no OTHERWISE clause User Action Either add an OTHERWISE clause to the CASE statement or change the value of the case select
40. Pascal condition handlers more efficiently than LIB ESTABLISH A condition handler set up by LIBSESTABLISH might interfere with the default error handling of the HP Pascal run time system and cause unpredictable results The following example shows how to establish a condition handler using the HP Pascal procedure ESTABLISH EXTERNAL ASYNCHRONOUS FUNCTION Handler VAR Sigargs Sigarr VAR Mechargs Mecharr INTEGER EXTERN ESTABLISH Handler To establish the handler call the ESTABLISH procedure To remove an established handler call the predeclared procedure REVERT as follows REVERT As a result of this call the condition handler established in the current stack frame is removed When control passes from a routine any condition handler established during the routine s activation is automatically removed Error Processing and Condition Handling 8 5 8 3 2 Declaring Parameters for Condition Handlers A condition handler is an integer valued function that is called when a condition is signaled Two formal VAR parameters must be declared for a condition handler e An integer array to refer to the parameter list from the call to the signal routine the signal array that is the list of parameters included in calls to LIB SIGNAL or LIB STOP see Section 8 2 1 e An integer array to refer to information concerning the routine activation that established the condition handler the mechanism array The size and contents
41. a particular attribute class can appear in the same attribute list C 16 Diagnostic Messages DUPTYPALI Alignment already specified by type identifier type name DUPTYPALL Allocation already specified by type identifier type name DUPTYPATR Attribute already specified by type identifier type name DUPTYPDES Descriptor class already specified by type identifier type name DUPTYPSIZ Size already specified by type identifier type name DUPTYPVIS Visibility already specified by the type identifier type name Error An attribute specified for an object was already specified in the definition of the object s type ELEOUTRNG Element out of range Error A value specified in a set constructor used as a compile time constant expression does not fall within the subrange defined as the set s base type EMPTYCASE Empty case body Error You failed to specify any case labels and corresponding statements in the body of a CASE statement ENVERROR Environment resulted from a compilation with Errors Error When a program inherits an environment file that compiled with errors unexpected results may occur during the program s compilation The environment file inherited by the program compiled with errors Unexpected results may occur in the program now being compiled ENVFATAL Environment resulted from a compilation with Fatal Errors Error The environment file inherited by the program compiled with fatal errors Unex
42. a variable is written or read indirectly without explicit program action The most common occurrence for this is with item lists In that case the address of the variable is placed in the item list most likely using the IADDRESS routine This address is then used later when the entire item list is passed to a system service Without the VOLATILE attribute the compiler does not realize that the call to the system service or run time library routine uses the variable The UNBOUND attribute designates a routine that does not have a static link available to it Without a static link a routine can only access local variables parameters or statically allocated variables System services that require AST or action routines want the address of an UNBOUND routine Routines at the outer level of a PROGRAM or MODULE are UNBOUND by default The ASYNCHRONOUS attribute designates a routine that might be called asynchronously of any program action This allows the compiler to verify that the asynchronous routine only accesses local variables parameters and VOLATILE variables declared at outer levels Without the assurance that only VOLATILE variables are used the asynchronous routine might access incorrect data or data written by the routine will not be available to the main program 6 5 Using Item Lists Many OpenVMS system services use item lists Item lists are sequences of control structures that provide input to the system service and that desc
43. actual variable passed in to the routine Value parameters are parameters that are local copies of the expression passed into the routine Changes made 5 16 Calling Conventions to the value parameter are not reflected back to any actual parameter passed in to the routine Routine parameters are parameters that represent entire routines that may be called from inside the called routine The HP Pascal compiler provides three parameter mechanisms by immediate value by reference and by descriptor These forms represent the actual implementation used by the compiler for the parameter These forms are denoted by the IMMEDIATE CLASS S CLASS AJ and CLASS NCAJ attributes note the REFERENCE attribute doesn t just specify a parameter mechanism but also specifies a parameter semantic model HP Pascal also provides a fourth parameter model called foreign parameters These parameters become either VAR or value parameters depending on the actual parameter If the actual parameter is a variable then the parameter is treated as a VAR parameter If the actual parameter is an expression then the parameter is treated as a value parameter These parameters are denoted by the o REF DESCR and STDESCR foreign mechanism specifiers and the REFERENCE attribute identical in behavior to the REF foreign parameter specifier Be careful not to confuse the term value parameter with the by immediate value mechanism The
44. allocated by the current compilation therefore the specification of an allocation attribute is meaningless EXTRNAMDIFF External names are different Information This message can appear as additional information on other error messages EXTRNCFLCT PSECT or FORWARD conflicts with EXTERNAL visibility Error The storage for an external variable or routine is not allocated by the current compilation therefore the specification of an allocation attribute is meaningless FILEVALASS FILE evaluation assignment is not allowed Error You cannot attempt to evaluate a file variable or assign values to it FILHASSCH FILE component may not contain nonstatic types or discriminant identifiers Error HP Pascal restricts components of files to those with compile time size FILOPNDREQ FILE operand required Error The EOF EOLN and UFB functions require parameters of file types Diagnostic Messages C 19 FILVARFIL FILE VARIABLE parameter must be of a FILE type Error The file variable parameter to the OPEN and CLOSE procedures must denote a file variable FLDIVPOS Field field name is illegally positioned Error A POS attribute attempted to position a record field before the end of the previous field in the declaration FLDNOTKNOWN Unknown record field Error FLDONLYTXT Field width allowed only when writing to a TEXT file Error FLDRADINT Field width or radix expression must be of type INTEGER Error Th
45. and the two abbreviated forms refer to the version of the OpenVMS operating system that runs on the Intel Itanium architecture The following typographic conventions might be used in this manual Ctrl x A sequence such as Ctrl x indicates that you must hold down the key labeled Ctrl while you press another key or a pointing device button PF1 x A sequence such as PF1 x indicates that you must first press and release the key labeled PF1 and then press and release another key or a pointing device button Return In examples a key name enclosed in a box indicates that you press a key on the keyboard In text a key name is not enclosed in a box In the HTML version of this document this convention appears as brackets rather than a box A horizontal ellipsis in examples indicates one of the following possibilities e Additional optional arguments in a statement have been omitted e The preceding item or items can be repeated one or more times e Additional parameters values or other information can be entered A vertical ellipsis indicates the omission of items from a code example or command format the items are omitted because they are not important to the topic being discussed xiii CO U bold type italic type UPPERCASE TYPE numbers xiv In command format descriptions parentheses indicate that you must enclose choices in parentheses if you specify more than one In comman
46. case unexpected results can occur Note that informational messages generated when you specify the STANDARD qualifier do not appear if NOWARNINGS is enabled NO ZERO HEAP OpenVMS 164 and OpenVMS Alpha systems ZERO HEAP default Specifies that heap memory should be zeroed after allocation By default the Pascal RTL will return zero filled memory for each call to the NEW built in Using the NOZERO HEAP qualifier can increase runtime performance For More Information e On debugging Section 4 1 e On text libraries Section 1 1 4 e On LSE and SCA information Section 4 2 e On error messages Section 1 4 On the contents of a compiler listing Section 1 1 3 e On Pascal standards HP Pascal for OpenVMS Language Reference Manual e On using environment files Section 2 1 e On the AND THEN and OR ELSE Boolean operators HP Pascal for OpenVMS Language Reference Manual Compiling HP Pascal Programs 1 25 1 1 3 Contents of the Compilation Listing File You control the contents of a compilation listing by appending qualifiers to the PASCAL command Table 1 14 lists the parts of a complete compilation listing and the qualifiers that cause them to be generated Table 1 14 Compilation Listing Contents and Qualifiers Section Generated With Table of contents OpenVMS LIST SHOW TABLE_OF_CONTENTS VAX systems Source code LIST Cross reference LIST CROSS_REFERENCE Machine code LIST MACHINE_CODE Inli
47. evaluated is not specified in fact the compiler may evaluate them simultaneously Regardless of which subexpression is evaluated first if its value is FALSE the condition being tested in the WHILE statement is also FALSE The other subexpression need not be evaluated at all In this case the body of the loop is never executed To force the compiler to evaluate expressions in left to right order with short circuiting you can use the AND THEN operator as shown in the following example WHILE i 10 AND THEN a i lt gt 0 DO BEGIN a i a i 1 i i 1 END Value Propagation The compiler keeps track of the values assigned to variables and traces the values to most of the places that they are used If it is more efficient to use the value rather than a reference to the variable the compiler makes this change This optimization is called value propagation Value propagation causes the object code to be smaller and may also improve run time speed 3 8 Program Correctness Optimization and Efficiency 3 1 11 3 1 12 Value propagation performs the following actions e It allows run time operations to be replaced with compile time operations For example Pi 3 14 Pi Over 2 Pi 2 In a program that includes these assignments the compiler recognizes the fact that Pi s value did not change between the time of Pi s assignment and its use So the compiler would use Pi s value instead of a reference to Pi
48. file pascal list show structure layout test pas Comments Offset Size 5 Bytes R In PROGRAM A PACKED RECORD Size 0 Bytes 1 Bit Fl BOOLEAN Align 1 Bit 4 Bytes F2 INTEGER END This output shows the size of the record R as well as the sizes and offsets of the records fields It also highlights any components that were poorly sized or poorly aligned Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha 9 9 9 7 7 Applications with External Data Dependencies If your application has external data dependencies the process is more involved since you have to isolate and understand the dependencies Possible steps when porting the code include e Using the ALIGN VAX qualifier e Using the ENUMERATION_SIZE BYTE qualifier e Using the FLOAT D_FLOAT qualifier if you have any DOUBLE binary data e Leaving the code exactly as is This should produce the same behavior on the OpenVMS I64 or OpenVMS Alpha system as you had on your OpenVMS VAX system with the following exception Using D Floating data on Alpha systems only provides 53 bits of mantissa instead of 56 bits as on VAX systems using D_floating data on OpenVMS I64 systems causes the compiler to convert to from D Floating data and IEEE T_Floating data to actually perform any needed operations You then have to identify which records in your program have external data dependencies These include binary files for example FILE OF xxx shared memory sections with ot
49. floating point operations outside of loops or reduce or remove floating point operations totally thereby improving performance The default ACCURACY SENSITIVE directs the compiler to avoid certain floating point trasformations that might slighly affect the program s accuracy NOJCHECK CHECK BOUNDS DECLARATIONS default Directs the compiler to generate code to perform run time checks A single identifier or a list of identifiers enclosed in parentheses can follow CHECK these identifiers are the names of options that tell the compiler which aspects of the compilation unit to check The system issues an error message and normally terminates execution if any of the conditions in the options list occur Table 1 3 lists the available checking options their corresponding actions and their negations Compiling HP Pascal Programs 1 7 Table 1 3 CHECK Qualifier Options Option Action Negation ALL BOUNDS Generates checking code for all NONE options Verifies that an index expression is NOBOUNDS within the bounds of an array s index type that character string sizes are compatible with the operations being performed and that schemata are compatible CASE SELECTORS Verifies that the value of a case NOCASE SELECTORS selector is contained in the corresponding case label list DECLARATIONS Verifies that schema definitions yield NODECLARATIONS valid types and that uses of GOTO from one block to an encl
50. following type s32 packed array 1 32 of char var qp quad s begin qp my alloc routine size s32 some routine stdescr qp end Passing variables accessed with 64 bit pointers to formal parameters declared with DESCR or STDESCR foreign mechanism specifiers Passing variables accessed with 64 bit pointers to conformant array or conformant varying parameters Passing variables accessed with 64 bit pointers to STRING parameters At run time the compiler will generate incorrect code when passing a VAR parameter that is accessed with a 64 bit pointer to a parameter that requires a descriptor The generated code will build the descriptor with the lower 32 bits of the 64 bit address For example 6 18 Programming on OpenVMS Systems type s32 packed array 1 32 of char var qp quad s procedure a p packed array l u integer of char begin writeln a end procedure b var p s32 begin a p This will generate a bad descriptor end begin qp my alloc routine size s32 b qp end 6 7 2 Using 64 Bit Pointers with System Definition Files For routines that have parameters that are 64 bit pointers the Pascal definition uses a 64 bit record type The definition files do not support either the INTEGER64 datatype or 64 bit pointers You can override the formal definition inside of definition files by using a foreign mechanism specifier that is 7IMMED
51. following example shows a more significant application of this kind of compiler optimization in which you could not reasonably modify the source code to achieve the same effect VAR a b ARRAY 1 25 1 25 OF REAL In the executable section a 1 f bI Without optimization this source program would be compiled as follows tl j 1 25 i t2 j 1 25 i a t1 b t2 Variables t1 and t2 represent equivalent expressions The compiler eliminates this redundancy by producing the following optimization t j 2 25 a 3 4 Program Correctness Optimization and Efficiency 3 1 3 Elimination of Unreachable Code The compiler can determine which lines of code if any are never executed and eliminates that code from the object module being produced For example consider the following lines from a program CONST Debug Switch FALSE In the executable section IF Debug Switch THEN WRITELN Error found here The IF statement is designed to write an error message if the value of the symbolic constant Debug Switch is TRUE Suppose that the error has been removed and you change the definition of Debug Switch to give it the value FALSE When the program is recompiled the compiler can determine that the THEN clause will never be executed because the IF condition is always FALSE no machine code is generated for this clause You need not remove the IF statement from the source program Code that i
52. for all unidentified condition statuses the handler resignals A handler must always follow this behavior Example 2 ASYNCHRONOUS FUNCTION Handler 1 VAR SA Sig Args VAR MA Mech Args UNSAFE INTEGER BEGIN IF SA 1 SS UNWIND THEN BEGIN cleanup END Handler 1 SS RESIGNAL END When writing a handler remember that it can be activated with a condition of SS UNWIND signifying that the establisher s stack frame is about to be unwound If the establisher has special cleanup to perform such as freeing dynamic memory closing files or releasing locks the handler should check for the SS UNWIND condition status If there is no cleanup the required action of resignaling all unidentified conditions results in the correct behavior On return from a handler activated with SS UNWIND the stack frame of the routine that established the handler is deleted unwound Example 3 ASYNCHRONOUS FUNCTION Handler 2 VAR SA Sig Args VAR MA Mech Args UNSAFE INTEGER BEGIN IF LIBSMATCH COND SA 1 condition name lt gt 0 THEN BEGIN cleanup MA 3 expression establish function result seen by caller MA 11 on OpenVMS 164 OpenVMS Alpha SUNWIND unwind to caller of establisher END Handler 2 SS RESIGNAL END 8 12 Error Processing and Condition Handling A handler can perform a default unwind to force return to the caller of its establisher If the establisher is a function
53. for more information on sets SETNOTRNG set element is not in range 0 255 Explanation Sets of INTEGER or UNSIGNED must be in the range of 0 255 User Action Modify the declaration to specify a smaller range C 84 Diagnostic Messages STRASGLEN string assignment length error Explanation Your program attempted to assign to a string variable a character string that is longer than the declared maximum length of the variable if the variable s type is VARYING or that is not of the same length as the variable if the variable s type is PACKED ARRAY OF CHAR User Action Correct the program so that the string is of a correct length for the variable to which it is being assigned STRCOMLEN string comparison length error Explanation Your program attempted to compare two character strings that do not have the same current length User Action Correct the program so that the two strings have the same length at the time of the comparison SUBASGVAL subrange assignment value out of range Explanation Your program attempted to assign to a subrange variable a value that is not contained in the subrange type User Action Correct the program so that all values assigned to a subrange variable fall within the variable s type SUBSTRSEL SUBSTR selection error Explanation A SUBSTR function attempted to extract a substring that was not entirely contained in the original string User Action Correct the call to SUBSTR so that it specifi
54. from the command line and the linker cannot locate the definition for a specified global symbol reference The following error messages appear when a main program in OCEAN OBJ calls a subprogram in SEAWEED OBJ that is not specified in the LINK command LINK W NUDFSYMS 1 undefined symbol LINK I UDFSYMS SEAWEED LINK W USEUNDEF module OCEAN references undefined symbol SEAWEED LINK W DIAGISUED completed but with diagnostics oo oo ovo oo For More Information e On the complete list of HP Pascal compile time and run time errors Appendix C e On the complete list of linker messages HP OpenVMS Linker Utility Manual 1 38 Compiling HP Pascal Programs 2 Separate Compilation Pascal allows you to divide your application into subprograms by creating procedures and functions HP Pascal allows you further modularity by allowing you to create compilation units called programs and modules that can be compiled separately This chapter discusses the following topics about separate compilation e Section 2 1 ENVIRONMENT HIDDEN and INHERIT Attributes e Section 2 2 Interfaces and Implementations e Section 2 3 Data Models e Section 2 4 Separate Compilation Examples Note The sections at the beginning of this chapter use code fragments from the examples in this chapter and in the online example directory which by default is PASCAL EXAMPLES For More Information e On the ENVIRONMENT HIDDEN and INH
55. if the corresponding schema types are used in certain Pascal constructs However the Debug information generated to describe the schema types always requires the compiler generated variables and routines This is because a user might ask the Debugger to perform some operation on the variable that did not appear in the source code Therefore if you omitted an OBJ file on the LINK command and did not get a linker error you might get an error if the DEBUG qualifier was used All OBJ files from modules creating environments must be included on the LINK command line if they contain variables or routines either user generated or compiler generated To receive the full benefit of the linker s timestamp verification you should include all OBJ files on the LINK command 2 2 Interfaces and Implementations If your application requires you can use a method of creating and inheriting environment files that minimizes the number of times you have to recompile compilation units This method involves the division of module declarations into two separate modules an interface module and an implementation module The interface module contains data that is not likely to change constant definitions variable declarations and external routine declarations The implementation module contains data that may change bodies of the routines declared in the interface module and private types variables routines and so forth The interface module creates the env
56. in length 7 2 Input and Output Processing 7 1 4 Variable Length with Fixed Length Control Field VFC Component Format The HP Pascal I O model does not provide a direct means to create files of variable length components with fixed length control fields VFC If you open a file of this component format HP Pascal treats the file like a file of variable length components If you want to create files of this component format you must write a user action function For More Information e On user action functions Section 7 2 On VFC components Guide to OpenVMS File Applications 7 1 5 Random Access by Record File Address RFA The HP Pascal I O model does not allow random access by record file address If you want to use this type of access you must write a user action function RMS supports random access by Record File Address RFA for relative and indexed files and for sequential files only on disk The RFA is a unique number supplied for files on disk The RFA remains constant as long as the record is in the file RMS makes the RFA available to your program every time the record is stored or retrieved Your program can either ignore the RFA or it can keep it as a random access pointer to the record for subsequent accesses If your disk file is sequential with variable length records the RFA provides the only method for randomly accessing records of that file For More Information e On user action functions Section 7 2
57. in the first floating point register designated as f8 5 2 Calling Conventions If the value is too large to be represented in 64 bits if its type is a string type PACKED ARRAY OF CHAR VARYING OF CHAR or STRING or if the type is nonstatic the calling routine allocates the required storage An extra parameter a pointer to the location where the function result will be stored is added to the beginning of the calling routine s actual parameter list On OpenVMS Alpha Systems An nonfloating point scalar type a schematic subrange an array a record or set with size less than 64 bits is returned in the first integer register designated as r0 If the value is less than 64 bits r0 is sign extended or zero extended depending on the type A floating point value that can be represented in 64 bits of storage is returned in the first floating point register designated as f0 If the value is too large to be represented in 64 bits if its type is a string type PACKED ARRAY OF CHAR VARYING OF CHAR or STRING or if the type is nonstatic the calling routine allocates the required storage An extra parameter a pointer to the location where the function result will be stored is added to the beginning of the calling routine s actual parameter list On OpenVMS VAX Systems If the value can be represented in 32 bits of storage it is returned in register RO If the value is less than 32 bits the upper bits of RO are undefined If
58. number is greater than MAXINT Error LABUNDECL Undeclared label label name Error HP Pascal requires that you declare all labels in a LABEL declaration section before you use them in the executable section LABUNSATDECL Unsatisfied declaration of label label name is not local to block name Error A label that prefixes a statement in a nested block was declared in an enclosing block LIBESTAB LIB ESTABLISH is incompatible with HP Pascal use predeclared procedure ESTABLISH Warning HP Pascal establishes its own condition handler for processing Pascal specific run time signals Calling LIBSESTABLISH directly replaces the handler supplied by the compiler with a user written handler the probable result is improper handling of run time signals You should use Pascal s predeclared ESTABLISH procedure to establish user written condition handlers Diagnostic Messages C 29 LISTONEND LIST attribute allowed only on final formal parameter Error LISTUSEARG Formal parameter has LIST attribute use predeclared function ARGUMENT Error A formal parameter with the LIST attribute cannot be directly referenced You should use the predeclared function ARGUMENT to reference the actual parameters corresponding to the formal parameter LNETOOLNG Line too long is truncated to 255 characters Error A source line cannot exceed 255 characters If it does the compiler disregards the remainder of the line LOWGTRHI
59. of the item list is initialized Since the second cell is the last cell the terminator field must be filled in with a value of 0 6 6 Using Foreign Mechanism Specifiers on Actual Parameters The definition files provided by HP Pascal SYS LIBRARY STARLET PAS and so forth are created from a generic description language used by the OpenVMS operating system Since this description language does not contain all the features found in HP Pascal some of the translations do not take advantage of HP Pascal features Also since several of the system services are generic in nature it is impossible to provide a definitive definition for every situation If a formal parameter definition does not reflect the current usage you can use a foreign mechanism specifier to direct the compiler to use a different passing mechanism or different descriptor type than the default for that parameter Consider the following e ASTADR parameter Many system services define this parameter to be a procedure parameter with no formal parameters This is because the format of the arguments passed to the AST routine vary with the system service If you specify a routine with parameters as the actual parameter to an ASTADR parameter you will receive a compile time error saying that the formal parameter and actual parameter have different parameter lists To solve this problem you can specify the IMMED foreign mechanism specifier on the actual parameter This causes th
60. of the mechanism array is different on OpenVMS I64 OpenVMS Alpha and OpenVMS VAX systems For example a condition handler can be defined as follows TYPE Sigarr ARRAY 0 9 OF INTEGER Mecharr ARRAY 0 SIZE CHF2STYPE 4 DIV 4 OF INTEGER EXTERNAL ASYNCHRONOUS FUNCTION Handler VAR Sigargs Sigarr VAR Mechargs Mecharr INTEGER EXTERN ESTABLISH Handler The signal procedure passes the following values to the array Sigargs Value Description Sigargs 0 The number of parameters being passed in this array parameter count Sigargs 1 The primary condition being signaled condition value See Section 8 3 4 for a discussion of condition values Sigargs 2 to n The optional parameters supplied in the call to LIB SIGNAL or LIB STOP note that the index range of Sigargs should include as many entries as are needed to refer to the optional parameters The routine that established the condition handler passes the following values which contain information about the establisher s routine activation to the array Mechargs 8 6 Error Processing and Condition Handling OpenVMS 164 OpenVMS Alpha OpenVMS VAX Value Value Value Description Mechargs 0 Mechargs 0 Mechargs 0 The number of parame ters being passed in this array Not available Mechargs 2 Mechargs 1 The address of the stack Mechargs 2 Mechargs 4 Mechargs 11 Mechargs 13 Not available Mechargs 4 Mechargs 11
61. on the compile command line STDFLDHIDPTR Nonstandard record field identifier field identifier name hides type identifier field identifier name Information STDFORIN Nonstandard SET iteration in FOR statement Information This message is issued if you have specified a standard argument other than extended on the compile command line STDFORMECH Nonstandard foreign mechanism specifier Information This message refers to an extension to Pascal and is issued only if you have specified the standard switch on the compile command line Diagnostic Messages C 49 STDFORWARD Nonstandard PROCEDURE FUNCTION block routine name and its FORWARD heading are not in the same section Information The Extended Pascal standard requires that FORWARD declared routines must specify their corresponding blocks without intervening LABEL CONST TYPE or VAR sections This message is issued only if you have specified the extended argument to the standard switch on the compile command line STDFUNIDEVAR Nonstandard function identified variable Information This message is issued if you have specified a standard argument other than extended on the compile command line STDFUNCTRES Nonstandard FUNCTION returning a value of a type name type Information The ability of functions to have structured result types is an extension to Pascal This message is issued only if you have specified the standard switch on the compile command line
62. packed record f1 boolean f2 integer end begin end 9 8 Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha In this program the compiler can highlight the following pascal usage performance test pas fl boolean PASCAL I COMNOTSIZ Component is not optimally sized at line number 4 in file DISKS DIR TEST PAS 32 f2 integer PASCAL I COMNOTALN Component is not optimally aligned at line number 5 in file DISKS DIR TEST PAS 32 PASCAL S ENDDIAGS PASCAL completed with 2 diagnostics In this example the size of the Boolean field in the PACKED ARRAY is only 1 bit Single bit fields require additional instructions to process The integer field is not aligned on a well aligned boundary for the target system The USAGE PERFORMANCE qualifier gives performance information customized to the target system For example on an OpenVMS 164 or OpenVMS Alpha system INTEGERs should be on a longword boundary on an OpenVMS VAX system INTEGERs need only be aligned on a byte boundary for good performance The SHOW STRUCTURE_LAYOUT command line option This option causes the compiler to generate a structure layout summary in the listing file This summary gives size and offset information about variables types and fields It also flags the same information as the USAGE PERFORMANCE command line option For example compiling the above program with the following command produces the following in the listing
63. parameters These messages are enabled by default by the compiler Checks for passing components of packed structures to VAR parameters Checks for variables and record fields that are poorly sized or aligned on inefficient boundaries This provides the same information that is found in the SHOW STRUCTURE LAYOUT listing section Specifies whether the compiler should issue informational messages for routines that are declared but never called NONONGRNACC NOPACKED ACTUALS NOPERFORMANCE NOUNCALLABLE continued on next page Compiling HP Pascal Programs 1 23 Table 1 13 Cont USAGE Qualifier Options Option Action Negation UNCERTAIN Checks for variables that can NOUNCERTAIN be uninitialized depending on program flow UNINITIALIZED Checks for variables that are NOUNINITIALIZED UNSUPPORTED CDD UNUSED VOLATILE OpenVMS I64 and OpenVMS Alpha systems known to be uninitialized Checks for usage of CDD Repository constructs that do not correspond to HP Pascal data types Checks for variables that are declared but never referenced Checks for VOLATILE variables that are not aligned properly On OpenVMS I64 and OpenVMS Alpha systems certain unaligned VOLATILE variables cannot be updated in an atomic fashion NOUNSUPPORTED CDD NOUNUSED NOVOLATILE The following types of variables are not checked for uninitialization e Variables that have a file component e Predeclare
64. relative or indexed organization User Action Make sure that the program is referencing the correct file See Chapter 7 to determine what file characteristics are appropriate for your application ERRDURCLO error during CLOSE Explanation RMS reported an unexpected error during execution of the CLOSE procedure The RMS error message is also displayed This message may also be issued with error severity when files are implicitly closed during a procedure or image exit User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for the description of the RMS error ERRDURDEL error during DELETE Explanation RMS reported an unexpected error during execution of a DELETE procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for the description of the RMS error C 68 Diagnostic Messages ERRDURDIS error during DISPOSE Explanation An error occurred during execution of a DISPOSE procedure An additional message that further describes the error may also be displayed User Action Make sure that the heap storage being freed was allocated by a successful call to the NEW procedure and that it has not been already freed If an additional message is shown see the OpenVMS System Messages and Recovery Procedures Reference Manual for the description of that message ERRDUREXT error during EXTEND Explanation RMS reported an
65. s condition reporting can involve one or more of the following actions e Maintaining a count of exceptions encountered during program execution e Resignaling the same condition to send the appropriate message to the output file e Changing the severity field of the condition value and resignaling the condition e Signaling a different condition for example the production of a message designed for a specific application A handler can control execution in several ways e By continuing from the signal If the signal was issued through a call to LIB STOP the program exits e By doing a nonlocal GOTO operation see Section 8 5 Example 5 e By unwinding to the establisher at the point of the call that resulted in the exception The handler can then determine the function value returned by the called routine e By unwinding to the establisher s caller the routine that called the routine which established the handler The handler can then determine the function value returned by the called routine 8 3 Writing Condition Handlers The following sections describe how to write and establish condition handlers and provide some simple examples 8 3 1 Establishing and Removing Handlers To use a condition handler you must first declare the handler as a routine in the declaration section of your program then within the executable section you must call the predeclared procedure ESTABLISH The ESTABLISH procedure sets up an HP Pascal
66. structured statement may yield incorrect behavior and or additional compile time errors GOTSZOVFL GOT table overflow for module name Error The GOT Global Offset Table for the module is too large Break up the module into multiple modules GTR32BITS routine name cannot accept parameters larger than 32 bits Error DEC and UDEC cannot translate objects larger than 32 bits into their textual equivalent HIDATOUTER HIDDEN legal only on definitions and declarations at outermost level Error When an environment file is being generated it is possible to prevent information concerning a declaration from being included in the environment file by using the HIDDEN attribute However because an environment file consists only of declarations and definitions at the outermost level of a compilation unit the HIDDEN attribute is legal only on these definitions and declarations IDENTGTR31 Identifier longer than 31 characters exceeds capacity of compiler Warning IDNOTLAB Identifier symbol name not declared as a label Error C 22 Diagnostic Messages IDXNOTCOMPAT Index type is not compatible with declaration Error The type of an index expression is not assignment compatible with the index type specified in the array s type definition IDXREQDKEY Creating INDEXED organization requires dense keys Warning When you specify ORGANIZATION INDEXED when opening a file with HISTORY NEW or UNKNOWN the file s alternate key
67. syntax for an integer PAS K_INVSYNOCT 39 String is invalid syntax for an octal value PAS K_INVSYNREA 33 String is invalid syntax for a real number PAS K_INVSYNUNS 34 String is invalid syntax for an unsigned integer PAS K_KEYCHANOT 72 Changing the key field is not allowed PAS K_KEYDEFINC 10 KEY nnn definition is inconsistent with this file continued on next page Errors Returned by STATUS and STATUSV Functions A 3 Table A 1 Cont STATUS and STATUSV Return Values Name Value Meaning PAS K_KEYDUPNOT 71 Duplication of key field is not allowed PAS K_ KEYNOTDEF 11 KEY nnn is not defined in this file PAS K_KEYVALINC 70 Key value is incompatible with file s key nnn PAS K_LINTOOLON 52 Line is too long exceeds record length by nnn characters PAS K_LINVALEXC 122 LINELIMIT value exceeded PAS K_NEGWIDDIG 53 Negative value in width or digits of a field width specification is invalid PAS K_NOTVALTYP 35 String is not a value of type type PAS K_ORGSPEINC 8 Specified organization is inconsistent with this file PAS K_RECLENINC 6 Specified record length is inconsistent with this file PAS K_RECTYPINC 7 Specified record type is inconsistent with this file PAS K_RESNOTALL 124 RESET is not allowed for an internal file that has not been opened PASS K REWNOTALL 123 REWRITE is not allowed for a file opened for sharing PAS K SUCCESS 0 Last file operation completed successfully PAS K
68. the procedure value on OpenVMS VAX systems the entry mask of the routine is called This address may be sufficient information to successfully invoke an unbound routine but not a bound routine Bound routines are represented as a pair of addresses one pointing to the procedure value and the other to the frame pointer to the routine in which the routine was declared UNCALLABLE Routine name can never be called Information UNCERTAIN Variable name has not been initialized Information C 60 Diagnostic Messages UNDECLFRML Undeclared formal parameter symbol name Error A formal parameter name listed in a nonpositional call to a routine does not match any of the formal parameters declared in the routine heading UNDECLID Undeclared identifier symbol name Error In Pascal an identifier must be declared before it is used There are no default or implied declarations UNDSCHILL Undiscriminated schema type is illegal Error An undiscriminated schema type does not have any actual discriminants Without discriminants the type size any nested ARRAY bounds and the offset of any nested RECORD fields are unknown UNINIT Variable name is fetched not initialized Information UNPREDRES Calling FUNCTION function name declared FORWARD may yield unpredictable results Warning By using FORWARD declared functions in actual discriminant expressions you can cause infinite loops at run time or acc
69. the data type of the actual parameter The mechanism specifier appears before the name of a formal parameter Table 5 3 lists the class and type of descriptor generated for parameters that can be passed using the by descriptor mechanism Table 5 3 Parameter Descriptors Parameter Type Descriptor Class and Type Value or VAR DESCR STDESCR Semantics Ordinal SINGLE DSC K CLASS S DSC K CLASS 8 DSC K DTYPE F DSC K DTYPE FS lDescriptor s D type depends on size of type continued on next page Calling Conventions 5 9 Table 5 3 Cont Parameter Descriptors Parameter Type Descriptor Class and Type DESCR STDESCR Value or VAR Semantics DOUBLE QUADRUPLE RECORD ARRAY ARRAY OF VARYING OF CHAR Conformant ARRAY Conformant ARRAY OF VARYING OF CHAR VARYING OF CHAR Conformant VARYING OF CHAR STRING Schema name DSC K CLASS S DSC K DTYPE D DSC K_DTYPE_G DSC K DTYPE FT DSC K CLASS S DSC K DTYPE H FX DSC K CLASS A NCA DSC K CLASS VSA DSC K DTYPE VT DSC K CLASS A NCA DSC K CLASS VSA DSC K DTYPE VT DSC K CLASS VS DSC K DTYPE VT DSC K CLASS VS DSC K DTYPE VT DSC K CLASS S DSC K DTYPE T DSC K CLASS S DSC K DTYPE T DSC K CLASS A NCA 5 DSC K CLASS VSA DSC K DTYPE VT DSC K CLASS VS DSC K DTYPE VT DSC K CLASS VS DSC K DTYPE VT Internal HP Pascal descriptor Descriptor s D type depen
70. the file specifications with plus signs the files are concatenated and compiled as one program The default file type for an input file is either PAS source file or TLB text library module e The output file used only with the ANALYSIS_DATA ENVIRONMENT LIST OBJECT or DIAGNOSTICS qualifiers file qualifier The name of a qualifier that indicates special processing to be performed by the compiler on the files to which the qualifier is attached identifier The name of one or more options that modify the ALIGN CHECK DEBUG DESIGN FLOAT OPTIMIZE SHOW STANDARD TERMINAL and USAGE qualifiers n The value of an integer constant When used with the ERROR_LIMIT qual ifier this parameter indicates the maximum number of errors to be detected before compilation ceases When used with the OPTIMIZATION LEVEL n qualifier this parameter indicates a specific level of optimization name value The definition of a constant or name with the specified value when used with the CONSTANT qualifier directory The input directory that contains the include file environment file or text library processed by a INCLUDE directive or INHERIT attribute when used with the INCLUDE qualifier 1 2 Compiling HP Pascal Programs 1 1 1 PASCAL Command Examples This section contains examples of PASCAL command lines PASCAL LIST DIR M The source file M PAS in directory DIR is compiled producing an object file name
71. the implementation of the routines declared in Example 2 1 Example 2 2 An Implementation Module for Graphics Objects and Routines Source File graphics implementation pas This module implements the graphics routines and data declarations made global by the interface module INHERIT Interface Predeclared graphics types and routines MODULE Graphics Implementation OUTPUT Declare routine bodies for declarations in the interface GLOBAL PROCEDURE Draw s Shape BEGIN CASE s t OF Circle WRITELN Code that draws a circle Rectangle WRITELN Code that draws a rectangle END END Procedure Draw GLOBAL PROCEDURE Rotate s Shape BEGIN WRITELN Rotating the shape s t END GLOBAL PROCEDURE Scale s Shape BEGIN WRITELN Scaling the shape s t END GLOBAL PROCEDURE Delete s Shape BEGIN WRITELN Deleting the shape s t END continued on next page Separate Compilation 2 17 Example 2 2 Cont An Implementation Module for Graphics Objects and Routines GLOBAL PROCEDURE Draw Logo VAR Initial Shape Shape Circle Declare object VALUE Coordinate X 50 0 Coordinate Y 50 0 CASE Circle OF Radius 15 75 BEGIN WRITELN Drawing a company logo Draw Initial Shape Code pauses for 30 seconds as the user looks at the logo Delete Initial Shape WRITELN Ready for the rest of the graphics program to
72. the value requires from 33 to 64 bits the low order bits of the result are returned in register RO and the high order bits are returned in register R1 If the value is too large to be represented in 64 bits if its type is a string type PACKED ARRAY OF CHAR VARYING OF CHAR or STRING or if the type is nonstatic the calling routine allocates the required storage An extra parameter a pointer to the location where the function result will be stored is added to the beginning of the calling routine s actual parameter list Note that functions that require the use of an extra parameter can have no more than 254 parameters functions that store their results in registers can have 255 parameters Calling Conventions 5 3 5 1 3 Contents of the Call Stack The OpenVMS I64 and OpenVMS Alpha system conventions define three types of procedures The calling process does not need to know what type it is calling the compiler chooses which type to generate based on the requirements of the procedure On OpenVMS 164 Systems On OpenVMS I64 systems the types of procedures are e Memory stack procedures These procedures allocate a memory stack and may maintain part or all of its caller s context on that stack e Register stack procedures These procedures allocate only a register stack and maintains its caller s context in registers e Null frame procedures These procedures do not allocate a memory stack or a register stack and the
73. to do so For example if each interface provided a different kind of constant or type as determined by your application and if the constants and types are not derived from one another the inheritance path in column B may be quite efficient and orderly and may require little recompiling and relinking Do not place the following in an implementation module e Nonstatic types and variables at the module level e A module initialization section TO BEGIN DO 2 10 Separate Compilation e A module finalization section TO END DO These restrictions are necessary because HP Pascal cannot determine the order of activation of initialization and finalization sections that do not directly follow an environment file inheritance path Since implementation modules do not create environment files the initialization and finalization sections in those modules are effectively outside of any inheritance path Also if you use the previously listed objects in implementation modules there may be attempts to access data that has not yet been declared Consider the following example In one file ENVIRONMENT interface MODULE Interface PROCEDURE x EXTERNAL END In another file INHERIT interface MODULE Implementation OUTPUT VAR My String STRING 10 GLOBAL PROCEDURE x BEGIN WRITELN My String END TO BEGIN DO My String Okay END In the previous example it is possible for you to cal
74. type RECORD NODSCRSCH No descriptor class for schematic types Error NOFLDREC No field field name in RECORD type type name Error The field specified does not exist in the specified record NOFRMINDECL Declaration of routine parameter routine name supplied no formal parameter list Information You specified actual parameters in a call on a formal routine parameter that was declared with no formal parameters Although such a call was legal in VAX Pascal Version 1 0 it does not follow the rules of the Pascal standard You should edit your program to reflect this change NOINITEXT Initialization not allowed on EXTERNAL variables NOINITINH Initialization not allowed on inherited variables Error You can initialize only those variables whose storage is allocated in this compilation NOINITVAR Cannot initialize symbol name it is not declared as a variable Error Variables are the only data items that can be initialized and they can be initialized only once NOLISTATTR Parameter to this predeclared function must have LIST attribute Error ARGUMENT and ARGUMENT_LIST_LENGTH require their first parameter to be a formal parameter with the LIST attribute NONATOMIC Unable to generate code for atomic access Warning Due to poor alignment the code generator is unable to generate an atomic code sequence to read or write the volatile object NONGRNACC Unable to generate code for requested granu
75. used as an exception handler e The called function result is a structured result type e The calling routine and the called routine do not have the same checking options enabled 3 6 Program Correctness Optimization and Efficiency The calling routine and the called routine do not use the same program section The called routine declares a routine parameter or is itself a routine parameter e The called routine s parameter list contains a LIST or TRUNCATE parameter a read only VAR parameter or a conformant parameter The called routine declares local file variables or contains any nonlocal GOTO operations The called routine references automatic variables in an enclosing scope The called routine uses or declares nonstatic types The second part of the algorithm performs tests to determine how desirable it is to inline the routine at a particular call point A failure to one of these tests can be thought of as a soft failure These tests check for the number of formal parameters number of local variables whether the called routine is directly recursive the number of direct calls to the routine and the size of both the calling and the called routine If an explicit OPTIMIZE NLINE attribute is specified on the routine declaration the hard failure tests are still performed however the soft failure tests are not So if the routine passes the hard failure tests that routine is inlined at all call points Specif
76. whose result is expected in RO or RO and R1 the handler must establish the return value by modifying the appropriate positions of the mechanism array the locations of the return RO and R1 values If the establisher is a function whose result is returned by the extra parameter method the handler must establish the condition value by assignment to the function identifier In this case you must observe two additional restrictions e The handler must be nested within the function e The function result must be declared VOLATILE Example 4 ASYNCHRONOUS FUNCTION Handler 3 VAR SA Sig Args VAR MA Mech Args UNSAFE INTEGER BEGIN IF LIBSMATCH COND SA 1 condition name EE THEN BEGIN cleanup MA 3 expression establish function result seen by caller SUNWIND MA 2 unwind to establisher 4 for OpenVMS I64 OpenVMS Alpha END Handler 3 SS RESIGNAL END A handler can also force return to its establisher immediately following the point of call In this case you should make sure that the handler understands whether the currently uncompleted call was a function call in which case a returned value is expected or a procedure call If the uncompleted call is a function call that will return a value in RO or RO and R1 then the handler can modify the mechanism array to supply a value If however the uncompleted call is a function call that will return a value using the extra parameter mechanism then there is no wa
77. 000 ee ee eee 4 12 5 Calling Conventions 5 1 OpenVMS Calling Standard 0 c eee eee 5 1 5 1 1 Parameter Lists 1 1 eee ete eee 5 2 5 1 2 Function Return Values l l eee 5 2 5 1 3 Contents of the Call Stack llle 5 4 5 1 4 Unbound Routines llle 5 6 5 2 Parameter Passing Semantics 0 000 5 6 5 3 Parameter Passing Mechanisms llle 5 7 5 3 1 By Immediate Value else 5 8 5 3 2 By Reference 0 0c cc eee 5 8 5 3 3 By i Dr raatorr PTT 5 9 5 3 3 1 CLASS_S Attribute 2 0 0 cee eee 5 13 5 3 3 2 CLASS A and CLASS NCA Attributes 5 13 5 3 3 3 STDESCR Mechanism Specifier 5 13 5 3 3 4 DESCR Mechanism Specifier 000005 5 14 5 3 4 Summary of Passing Mechanisms and Passing Semantics 5 15 5 4 Passing Parameters between HP Pascal and Other Lang ages ose Sek ors o gode y V ON Y eO ES US YU Roy s 5 16 5 4 1 Parameter Mechanisms Versus Parameter Semantics 5 16 5 4 2 Passing Nonroutine Parameters between HP Pascal and Other Languages l l 5 17 5 4 3 Passing Routine Parameters between HP Pascal and Other Languages iau ee dG se ae SUA Ke wee Y dep E RR TEES 5 20 6 Programming on OpenVMS Systems 6 1 Using System Definitions Files llle 6 2 Declaring System Routines llle 6 2 1 Methods Used to Obtain OpenVMS Data Types 6 2 2 Methods Used to Obtain
78. 9 Write sharing 7 14 Index 11 X XAB fields when calling OPEN 7 9 passed as parameter by run time library 7 10 used to write user action functions 7 1 Z ZERO_HEAP qualifier 1 25 Index 12
79. A MOD B the operand B must have a positive integer value This message is issued only when the MOD operation occurs in a compile time constant expression MSTBEARRAY Type must be ARRAY Error MSTBEARRVRY Type must be ARRAY or VARYING Error You cannot use the syntax index to refer to an object that is not of type ARRAY or VARYING OF CHAR MSTBEBOOL Control expression must be of type BOOLEAN Error The IF REPEAT and WHILE statements require a Boolean control expression MSTBEDEREF Must be dereferenced Information MSTBEDISCR Schema type must be discriminated Error An undiscriminated schema type is not allowed everywhere that a regular type name is allowed MSTBEORDSETARR Type must be ordinal SET or ARRAY Error MSTBEREC Type must be RECORD Error MSTBERECVRY Type must be RECORD or VARYING Error You cannot use the syntax Variable Identifier to refer to an object that is not of type RECORD or VARYING OF CHAR Diagnostic Messages C 31 MSTBESTAT Cannot initialize non STATIC variables Error You cannot initialize variables declared without the STATIC attribute in nested blocks nor can you initialize program level variables whose attributes give them some allocation other than static MSTBETEXT I O routine requires FILE VARIABLE of type TEXT Error The READLN and WRITELN procedures operate only on text files MULTDECL symbol name has multiple conflicting declarations reason s
80. ADDRESS function effect on optimization 3 17 use with VOLATILE and item lists 6 14 Identifier multiply declared 2 4 IF THEN ELSE statement effect on efficiency 3 14 IMMED mechanism specifier 5 8 on default parameter 6 11 IMMED specifier on actual parameters 6 16 Implementation Dependent Behavior 3 16 Implementation module 2 7 See also Separate compilation example of 2 17 INCLUDE directive use with text library 1 29 INCLUDE qualifier 1 15 with LINK command 1 34 Indexed file 7 2 locked component in 7 15 Infinite loop See Loop Information level error message effect of ERROR LIMIT 1 13 for extensions 1 20 INHERIT attribute 2 2 INITIALIZE attribute compared with UNBOUND 5 6 effect on routine call 5 6 Initial state specifier for array variable example 2 1 on a data type 2 13 on variant record fields example 2 12 variant record constructor example 2 13 Inline summary in listing file 1 28 Integer overflow run time checking of 1 7 3 15 Interface module 2 7 See also Separate compilation example of 2 16 Item list 6 14 using the SIZE function 6 16 using the VOLATILE attribute with 6 14 K KEY attribute C 25 Keywords use with LSE 4 3 L Language expression optimization of 3 8 3 16 order of evaluation 3 8 reordering of 3 2 Language Sensitive Editor Source Code Analyzer See LSE LSE SCA 3 2 LIB ESTABLISH routine establishing cond
81. ADONLY is specified by all programs that access the file Write sharing is accomplished when all programs specify SHARING READWRITE To prevent sharing specify SHARING NONE with the first program to access the file 7 14 Input and Output Processing Programs that specify SHARING READONLY or SHARING READWRITE can access a file simultaneously however file sharing can fail under certain circumstances For example a program without either of these parameters will fail when it attempts to open a file currently being accessed by some other program Or a program that specifies SHARING READONLY or SHARING READWRITE can fail to open a file because a second program with a different specification is currently accessing that file When two or more programs are write sharing a file each program should include a condition handler This error processing mechanism prevents program failure due to a record locking error For More Information e On record locking errors Section 7 4 On condition handling Chapter 8 e On the OPEN procedure HP Pascal for OpenVMS Language Reference Manual 7 4 Record Locking The RMS record locking facility along with the logic of the program prevents two processes from accessing the same component simultaneously It ensures that a program can add delete or update a component without having to do a synchronization check to determine whether that component is currently being accessed by another pr
82. BEGIN Syntax BEGIN expected SYNCOASSERP Syntax or expected SYNCOELRB Syntax or P expected SYNCOLCOMREP Syntax or expected SYNCOLON Syntax expected SYNCOMCOL Syntax or expected SYNCOMDO Syntax or DO expected SYNCOMEQL Syntax or expected SYNCOMMA Syntax expected SYNCOMRB Syntax or expected SYNCOMRP Syntax or expected SYNCOMSEM Syntax or expected SYNCONTMESS Syntax CONTINUE or MESSAGE expected SYNCOSERP Syntax or expected SYNDIRBLK Syntax directive or block expected Error The compiler either failed to find an important lexical or syntactical element where one was expected or it detected an error in such an element that does exist in your program C 56 Diagnostic Messages SYNDIRMIS Syntax directive missing EXTERNAL assumed Error In the absence of a directive where one is expected the compiler assumes that EXTERNAL is the intended directive and proceeds with compilation based on that assumption SYNDO Syntax DO expected SYNELIPSIS Syntax expected SYNELSESTMT Syntax ELSE or start of new statement expected SYNEND Syntax END expected SYNEQL Syntax expected SYNEQLLP Syntax or expected SYNERRCTE Error in compile time expression SYNEXPR Syntax
83. BLE G FLOATING QUADRUPLE BYTE 8 RECORD END BYTE 16 RECORD END BYTE 16 RECORD END BYTE 32 RECORD END PACKED ARRAY l u OF CHAR VARYING u OF CHAR BYTE n RECORD END BYTE n RECORD END BYTE n RECORD END BYTE n RECORD END BYTE n RECORD END BYTE n RECORD END BIT n 0 2 1 or BIT 32 UNSIGNED or BIT N RECORD END or ignored continued on next page Programming Tools 4 11 Table 4 3 Cont Equivalent CDD Repository Language and HP Pascal Data Types CDDL Data Type HP Pascal Data Type Bit unaligned Date and time Date Virtual field Varying string Overlay Pointer BIT n POS x 0 2 n 1 or BIT 32 POSG UNSIGNED or BIT n POS x RECORD END or ignored BYTE n RECORD END BYTE n RECORD END Ignored VARYING u OF CHAR Variant record Pointer type 4 3 2 CDD Repository Example In Example 4 3 the DICTIONARY directive is used to access the CDD Repository record definition Mail Order Info With this definition the HP Pascal program Show Keys performs ISAM file manipulation on an existing indexed file CUSTOMERS DAT Assume that CUSTOMERS DAT has the primary key Order Num and a field name called Zip Code Note Oracle CDD Repository has no equivalent for the HP Pascal KEY attribute which is required to create new indexed files You can use Oracle CDD Repository data definitions to open existing indexed files as in this example but
84. BUG ALL The negation NODEBUG is equivalent to DEBUG NONE NO DESIGN NODESIGN default Directs the compiler to accept design phase placeholders on all OpenVMS systems and comments on OpenVMS VAX systems as valid program elements within an HP Pascal program Placeholders are produced by you or by LSE SCA design comments are intended for use with LSE SCA Table 1 5 lists the options their corresponding action and their negation Compiling HP Pascal Programs 1 11 Table 1 5 DESIGN Qualifier Options Option Action Negation PLACEHOLDERS Directs the compiler to accept NOPLACEHOLDERS placeholders as valid program elements COMMENTS Directs the compiler to recognize design NOCOMMENTS OpenVMS VAX comments systems The DESIGN qualifier without an option is equivalent to DESIGN PLACEHOLDERS on OpenVMS 164 and OpenVMS Alpha systems and DESIGN PLACEHOLDERS COMMENTS on OpenVMS VAX systems NO DIAGNOSTICS NODIAGNOSTICS default Creates a file containing compiler messages and diagnostic information If you omit the file specification the diagnostics file defaults to the name of your source file with a DIA file type The diagnostics file is used by products such as LSE SCA ENUMERATION_SIZE keyword Controls the allocation of unpacked enumerated data types and Boolean data types which are considered to be an enumerated type containing two elements Note that specifying the ENUMERATION SIZE attribute overri
85. CDDMINOCC Ignoring minimum occurs attribute specified in CDD record description Information The HP Pascal compiler does not support the CDD MINIMUM OCCURS attribute Diagnostic Messages C 9 CDDONLYTYP DICTIONARY may only appear in a TYPE definition part Error The DICTIONARY directive is allowed only in the TYPE section of a program CDDRGHTJUST Ignoring right justified attribute specified in CDD record description Information The HP Pascal compiler does not support the CDD JUSTIFIED RIGHT clause CDDSCALE Ignoring scaled attribute specified in CDD record description Information The HP Pascal compiler does not support the CDD scaled data types CDDSRCTYPE Ignoring source type attribute specified in CDD record description Information The HP Pascal compiler does not support the CDD source type attribute CDDTAGDEEP CDD description nested variants too deep Error A CDD record description may not include more than 15 levels of CDD variants The compiler ignores variants beyond the fifteenth level CDDTAGVAR Ignoring tag variable and any tag values specified in CDD record description Information The HP Pascal compiler does not fully support the CDD VARIANTS OF field description statement The specified tag variable and any tag values are ignored CDDTOODEEP CDD description nested too deep Error Attributes for the CDD record description exceed the implementation s limit for record complexity Modify the C
86. Corporation or its subsidiaries in the United States and other countries Printed in the US ZK6140 This manual is available on CD ROM This document was prepared using DECdocument Version 3 3 1b Contents Preface 1s oe es musa eat hes Boe a Gee es e derit xi 1 Compiling HP Pascal Programs 1 1 PASCAL Command 0 0 eee eee 1 1 1 1 1 PASCAL Command Examples 00000 ee n 1 3 1 1 2 PASCAL Qualifiers 0 0 ce eee 1 3 1 1 3 Contents of the Compilation Listing File 1 26 1 1 3 1 Table of Contents OpenVMS VAX systems 1 27 1 1 3 2 Source Code 2 acca eee eae eee t rh ret 1 27 1 1 3 3 Cross Reference Section 0 00 cee eee eee 1 27 1 1 3 4 Machine Code Section llle 1 27 1 1 3 5 Structured Layout Section 0 0 00 000 e eee 1 28 1 1 3 6 Inline Summary OpenVMS VAX systems 1 28 1 1 3 7 Compilation Statistics 0 2 0 0 cee eee 1 28 1 1 4 Text Libraries sse csere bee ba ee kE nE eee Eas 1 29 1 1 4 1 Using the INCLUDE Directive for Text Libraries 1 29 1 1 4 2 Specifying Text Libraries on the Command Line 1 30 1 1 4 3 Defining Default Libraries 200 1 31 1 2 LINK Command i iecccoc ci bbc ba Rt Ree wR s 1 31 1 2 1 LINK Command Examples 00 0 eee eeee 1 32 1 2 2 LINK Qualifiers soeben rr mee qe eb qus 1 33 1 2 3 Object Module Libraries llle esee 1 36 1 3 RUN Command 2552232 wu ed
87. Creates a shareable image A shareable image has all of its internal references resolved but must be linked with one or more object modules to produce an executable image For example a shareable image can contain a library of routines or can be used by the system manager to create a global section for all users To include a shareable image as input to the linker you can insert the shareable image into a shareable image library and specify the library as input to the LINK command By default the linker automatically searches the system supplied shareable image library SYS LIBRARY IMAGELIB OLB after searching any libraries you specify on the LINK command line You can also include a shareable image by using a linker options file The NOSHAREABLE qualifier specifies that the image produced cannot be linked with other images NOJTRACEBACK TRACEBACK default Causes the generation of error messages to be accompanied by symbolic traceback information This information shows the sequence of calls that transferred control to the program in which the error occurred NOTRACEBACK suppresses production of traceback information The traceback capability is automatically included with the DEBUG qualifier therefore if you specify both DEBUG and NOTRACEBACK NOTRACEBACK has no effect For More Information e On debugging Section 4 1 e On object module libraries Section 1 2 3 e On shareable images options files and contents of map
88. DD description to reduce the level of nesting in the record description CDDTRUNCREF Reference string which exceeds 255 characters has been truncated Information The HP Pascal compiler does not support reference strings greater than 255 characters C 10 Diagnostic Messages CDDUNSTYP Unsupported CDD datatype standard data type name Information The CDD record description for an item has attempted to use a data type that is not supported by HP Pascal The HP Pascal compiler makes the data type accessible by declaring it as BYTE n RECORD END where n is the appropriate length in bytes Change the data type to one that is supported by HP Pascal or manipulate the contents of the field by passing it to external routines as variables or by using the HP Pascal type casting capabilities to perform an assignment CLSCNFVAL CLASS S is only valid with conformant strings Error When the CLASS S attribute is used in the declaration of an internal routine it can be used only on a conformant PACKED ARRAY OF CHAR The conformant variable must also be passed by value semantics CLSNOTALLW descriptor class name not allowed on a parameter of this type Error Descriptor class attributes are not allowed on formal parameters defined with either an immediate or a reference passing mechanism CMTBEFEOF Comment not terminated before end of input Error CNFCANTCNF Component of PACKED conformant parameter cannot be conformant Error
89. DEFINE command use with text library 1 31 Definition file for system routines 6 1 Definition sharing 4 8 to 4 13 Dependency checking environment file 2 5 Descriptor parameter 5 9 DESCR mechanism specifier 5 14 DESCR mechanism used with LIB FIND_ FILE 6 17 DESIGN qualifier 1 11 DIAGNOSTICS qualifier 1 12 DICTIONARY directive use with CDD Repository 4 9 example of 4 12 Dictionary Management Utility See DMU Directives DICTIONARY using to access CDD Repository definitions 4 8 DMU 4 8 E Emulation of Alpha instructions 1 6 Enumerated type used in graphical data model example 2 12 ENUMERATION SIZE qualifier 1 12 Environment file cascading inheritance of figure 2 3 cascading interfaces figure 2 9 creating 1 13 2 1 linking 1 32 Index 3 Environment file dependency checking 2 5 ENVIRONMENT qualifier 1 13 Error conditions detected by STATUS and STATUSV A 1 to A 4 Error messages compiler C 1 to C 65 run time C 65 to C 86 syntax of 1 38 ERROR LIMIT qualifier 1 13 Establisher routine definition of 8 2 ESTABLISH procedure 8 4 Evaluation order of operands effect of NOOPTIMIZE 1 18 EXAMINE command debugger automatic variables 4 2 use with LENGTH field 4 2 Examples of an implementation module 2 17 of an interface module 2 16 of separate compilation 2 16 Exception condition 8 1 EXECUTABLE qualifier with LINK command 1 34 EXPAND com
90. EN Contains OpenVMS system service definitions LIB messages MTH messages OTS messages SMG data structures and termtable STR messages RMS routine declarations system symbolic names and RMS data structures Run Time Library Definitions Files PASCAL ACLEDIT_ROUTINES PAS PEN PASCAL C_ROUTINES PAS PEN PASCAL CLI_ROUTINES PAS PEN PASCAL CMA ROUTINES PAS PEN PASCAL CONV ROUTINES PAS PEN PASCAL CVT ROUTINES PAS PEN PASCAL DCX ROUTINES PAS PEN PASCAL DTK ROUTINES PAS PEN PASCAL EDT_ROUTINES PAS PEN PASCAL FDL_ROUTINES PAS PEN PASCAL LBR_ROUTINES PAS PEN PASCAL LIB_ROUTINES PAS PEN PASCAL MAIL_ROUTINES PAS PEN PASCAL MTH_ROUTINES PAS PEN PASCAL NCS_ROUTINES PAS PEN Contains ACLEDIT routine entry points Contains C routine entry points Contains CLI routine entry points Contains routine entry points data structures and messages for DECthreads For more information on DECthreads see the Guide to the POSIX Threads Library Contains CONV routine entry points Contains CVT routine entry points Contains DCX routine entry points Contains DTK routine entry points data structures and messages Contains EDT routine entry points Contains FDL routine entry points Contains LBR routine entry points Contains LIB routine entry points Contains MAIL routine entry points Contains MTH routine entry points Contains NCS routine entry points 2These files ar
91. ERE EE ee P o E E AS cR ck cA E DMDDAD OD NOPPWNHONDOO PT 7 1 7 2 7 2 7 3 7 3 7 3 7 4 7 5 7 10 7 10 7 14 7 15 8 Error Processing and Condition Handling 8 1 8 2 8 2 1 8 2 2 8 3 8 3 1 8 3 2 8 3 3 8 3 4 8 3 5 8 4 8 5 Condition Handling Terms 0 0 ccc eee eens Overview of Condition Handling 0 000005 Condition Signals llle Handler Responses llle Writing Condition Handlers 0 0 00 ce eee Establishing and Removing Handlers Declaring Parameters for Condition Handlers Handler Function Return Values 0 000005 Condition Values and Symbols 0 00 ce eeee Using Condition Handlers that Return SS _CONTINUE Fault and Trap Handling OpenVMS VAX systems Examples of Condition Handlers 0000 9 Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha 9 1 9 7 2 9 7 3 9 7 4 9 7 5 9 7 6 9 7 7 Sharing Environment Files Across Platforms Default Size for Enumerated Types and Booleans Default Data Layout for Unpacked Arrays and Records Overflow Checking 0 0 ee eens Bound Procedure Values 0 0 00 cece eee eee eens Different Descriptor Classes for Conformant Array ParametetsS 2255 Reed esaet a ee ee Data Layout and Conversion llle Natural Alignment VAX Alignmen
92. ERIT attributes HP Pascal for OpenVMS Language Reference Manual e On compiling and executing programs and modules Chapter 1 2 1 ENVIRONMENT HIDDEN and INHERIT Attributes To divide your program into a program and a series of modules you need to decide according to the needs of your application which data types constants variables and routines need to be shared either by other modules or by the program To share data create an environment file by using the ENVIRONMENT attribute in a module Consider the following example Separate Compilation 2 1 Source File share data pas This program initializes data to be shared with another compilation unit ENVIRONMENT share data Module Share Data CONST Rate For Q1 0 1211 Rate For Q2 0 1156 Rate For Q3 0 1097 Rate For 04 0 11243 TYPE Initialized Type ARRAY 1 10 OF INTEGER VALUE 1 5 67 6 9 105 OTHERWISE 33 END If you do not specify a file name HP Pascal creates an environment file using the file name of the source file and a default extension of PEN Another compilation unit can access the types and constants in the previous example by inheriting the environment file as follows Source File program pas This code inherits data declarations and uses them in a program INHERIT share data PROGRAM Use Data OUTPUT VAR a by c Initialized Type Total REAL VALUE 0 0 BEGIN Total Total Total Rate For Q3 WRITE
93. ETK Explanation RMS reported an unexpected error during execution of the RESET or RESETK procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the RMS error ERRDURREW error during REWRITE Explanation RMS reported an unexpected error during execution of the REWRITE procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the RMS error C 70 Diagnostic Messages ERRDURTRU error during TRUNCATE Explanation RMS reported an unexpected error during execution of the TRUNCATE procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the RMS error ERRDURUNL error during UNLOCK Explanation RMS reported an unexpected error during execution of the UNLOCK procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the RMS error ERRDURUPD error during UPDATE Explanation RMS reported an unexpected error during execution of the UPDATE procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the RMS error ERRDURWHRI error dur
94. GH Low bound exceeds high bound Error The definition of the flagged subrange type is illegal because the value specified for the lower limit exceeds that for the upper limit MAXLENINT Max length must be a value of type integer Error The maximum length specified for type VARYING OF CHAR must be an integer in the range 1 65535 that is the type definition must denote a legal character string MAXLENRNG Max length must be in range 1 65535 Error The maximum length specified for type VARYING OF CHAR must be an integer in the range 1 65535 that is the type definition must denote a legal character string MAXNUMENYV Maximum number of environments exceeded Fatal More than 512 environment files were used in the compilation MECHEXTERN Foreign mechanism specifier allowed only on external routines Error MISSINGEND No matching END expected near line line number Information The compiler expected an END statement at a location where none was found Compilation proceeds as though the END statement were correctly located C 30 Diagnostic Messages MODINIT26 Module name limited to 26 characters when initialization required Error When a module contains schema types discriminated schema types variables of discriminated schema types or a TO BEGIN DO statement clause the module name is limited to 26 characters MODOFNEGNUM MOD of a negative modulus has no mathematical definition Error In the MOD operation
95. HP Pascal for OpenVMS User Manual Order Number AA PXSND TK January 2005 This manual contains information about selected programming tasks using the HP Pascal programming language Revision Update Information This revised manual supersedes the Compaq Pascal User Manual for OpenVMS Systems Version 5 7 Operating System OpenVMS 164 Version 8 2 or higher OpenVMS Alpha Version 6 1 or higher OpenVMS VAX Version 5 5 or higher Software Version HP Pascal for OpenVMS 164 Systems Version 5 9 HP Pascal for OpenVMS Alpha Systems Version 5 9 HP Pascal for OpenVMS VAX Systems Version 5 8 Hewlett Packard Company Palo Alto California Copyright 2005 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 Intel and Itanium are trademarks or registered trademarks of Intel
96. Integer Ptr to Integer EXTERN Marked Integer Mark Integer The parameter to PAS MARK2 can be 0 in which case the function value is only a pointer to a marker and cannot be used to store data B 4 PASSRELEASE p The PAS RELEASE2 function deallocates all storage allocated by NEW or PAS MARKz2 since the call to PAS MARK2 allocates the parameter p PAS MARK2 and PAS RELEASE2 are provided only for compatibility with some other implementations of HP Pascal Their use is not recommended in a modular programming environment PAS RELEASE2 disables AST delivery during its execution so it should not be used in a real time environment The PAS MARK2 and PAS RELEASE2 routines do not work with 64 bit pointers on OpenVMS 164 and OpenVMS Alpha PAS RELEASE2 is an external function that must be explicitly declared An example of its declaration and use is as follows TYPE Ptr_to Integer Integer VAR Marked Integer Ptr to Integer Entry Points to HP Pascal Utilities B 3 EXTERNAL PASSRELEASE2 PROCEDURE Release P UNSAFE Ptr to Integer EXTERN Release Marked Integer In this example Marked Integer is assumed to contain the pointer value returned by a previous call to PAS MARK2 For More Information e On PAS MARK2 Section B 3 B 4 Entry Points to HP Pascal Utilities C Diagnostic Messages This appendix summarizes the error messages that can be generated by an HP Pascal program at compile time an
97. LN b 7 b is of an initialized type END To build and run the application made up of the code in the previous examples use the following commands PASCAL SHARE DATA PASCAL PROGRAM LINK PROGRAM RUN PROGRAM 33 If a module contains variable declarations routine declarations schema types or module initialization or finalization sections you must link the program with the module that created the environment file to resolve external references To prevent errors you may wish to link programs with modules of inherited environment files as standard programming practice For example if 2 2 Separate Compilation SHARE DATA contained a variable declaration you must enter the following to resolve the external reference PASCAL SHARE DATA PASCAL PROGRAM LINK PROGRAM SHARE DATA RUN PROGRAM 33 For many applications it is a good idea to place all globally accessible data into one module create a single environment file and inherit that module in other compilation units that need to make use of that data Using environment files in this way reduces the difficulties in maintaining the data it is easier to maintain one file and it eliminates problems that can occur when you cascade environment files If compilation unit A inherits an environment file from compilation unit B and if unit B inherits a file from unit C then inheritance is cascading Figure 2 1 shows a cascading inheritance path and a noncascading inher
98. MS Language Reference Manual 3 3 4 Variant Records Because all the variants of a record variable are stored in the same memory location a program can use several different field identifiers to refer to the same storage space However only one variant is valid at a given time all other variants are undefined You must store a value in a field of a particular variant before you attempt to use it For example VAR X INTEGER a RECORD CASE t BOOLEAN OF TRUE b INTEGER FALSE c REAL END In the executable section x a b 5 aG sm 3205 x ism 5 Record a has two variants b and c which are located at the same storage address When the assignment a c 3 0 is executed the value of a b becomes undefined because TRUE is no longer the currently valid variant When the statement x a b 5 is executed for the second time the value of a b is unknown The compiler may choose not to evaluate a b a second time because it has retained the field s previous value To eliminate any misinterpretations caused by this assumption variable a should be associated with the VOLATILE attribute The compiler makes no assumptions about the value of VOLATILE objects For More Information e On variant records or on the VOLATILE attribute HP Pascal for OpenVMS Language Reference Manual 3 18 Program Correctness Optimization and Efficiency 3 3 5 Atomicity Granularity Volatility and Write Ordering When data is share
99. N PASCAL GRAPHICS MAIN PROGRAM LINK GRAPHICS MAIN PROGRAM GRAPHICS IMPLEMENTATION GRAPHICS INTERFACE RUN GRAPHICS MAIN PROGRAM If you need to change the code contained in any of the routine bodies declared in the implementation module you do not have to recompile the program to reflect the changes For example if you have to edit the implementation module you can regenerate the application with the following commands EDIT GRAPHICS IMPLEMENTATION PASCAL GRAPHICS IMPLEMENTATION LINK GRAPHICS MAIN PROGRAM GRAPHICS IMPLEMENTATION _S GRAPHICS INTERFACE RUN GRAPHICS MAIN PROGRAM In this manner interfaces and implementations can save you maintenance time and effort In addition the interface and implementation design allows you to better predict when cascading inheritance may provide maintenance problems Figure 2 3 shows two forms of cascading Separate Compilation 2 9 Figure 2 3 Cascading Using the Interface and Implementation Design Interface and Interface Implementation Interface and Interface Implementation Interface and Interface Implementation B ZK 1492A GE If the compilation units creating environment files are designed to contain both interface and implementation declarations the cascading in column may lead to more recompiling more relinking and more multiply declared identifiers The design shown in column B does not always provide easy maintenance but it is more likely
100. PERFORMANCE and SHOWZSTRUCTURE LAYOUT DCL qualifiers can be helpful for identifying poorly aligned records For PACKED keywords you can compile with and without the PACKED keyword to see if the fields are positioned at the same offsets or not Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha 9 11 You have classified the records with external data dependencies into e Records that are well aligned with both alignment enumeration formats e Records that are poorly aligned where conversion is not worthwhile e Records that are poorly aligned where conversion is worthwhile For the well aligned records no additional work is needed now but be aware that you still have an external data dependency that might cause problems if you add fields to the record in the future Isolate records that are not being converted into the same environment file or into the TYPE or VAR sections where you placed the records that you could not convert For records that are worth converting you need to plan how to convert the external binary data or cooperating software For cooperating software you need to ensure that it gets modified so it views the record with the natural layout You can determine the layout by using the SHOW STRUCTURE_ LAYOUT command line option described above For binary data you need to write a conversion program Converting existing binary data involves writing a program that reads the existing data into a poorly aligne
101. Pascal compiler does not support the CDD DEPENDING ON ITEM attribute CDDDFLOAT D floating CDD datatype was specified when compiling with G FLOATING Warning The CDD record description contains a D floating data type while compiling with G floating enabled It is replaced with BYTE 8 RECORD END CDDFLDVAR CDD record description contains field s after CDD variant clause Error The CDD record description contains fields after the CDD variant clause Because HP Pascal translates a CDD variant clause into a Pascal variant clause and a Pascal variant clause must be the last field in a record type definition the fields following the CDD variant clause are illegal CDDGFLOAT G floating CDD datatype was specified when compiling with NOG FLOATING Warning The CDD record description contains a G floating data type while compiling with D floating enabled It is replaced with BYTE 8 RECORD END CDDILLARR Aligned array elements can not be represented replacing with BIT RECORD END Information The HP Pascal compiler does not support CDD record descriptions that specify an array whose array elements are aligned on a boundary greater than the size needed to represent the data type It is replaced with BIT n RECORD END where n is the appropriate length in bits CDDINITVAL Ignoring specified initial value specified in CDD record description Information The HP Pascal compiler does not support the CDD INITIAL VALUE clause
102. Process Name INHERIT SYSSLIBRARY STARLET PROGRAM Userid OUTPUT TYPE Uword WORD 0 65535 Itmlst Cell PACKED RECORD CASE INTEGER OF 1l Buf Len Uword Item Code Uword Buf Addr INTEGER Len Addr INTEGER 2 Term INTEGER END VAR Username String VOLATILE VARYING 12 OF CHAR Itmlst ARRAY 1 2 OF Itmlst Cell ZERO BEGIN Itmlst 1 Buf Len 12 12 bytes returned Itmlst 1 Item Code JPI _ USERNAME return user name Itmlst 1 Buf Addr Store returned name here IADDRESS Username String BODY Itmlst 1 Len Addr store returned length here IADDRESS Username String LENGTH Itmlst 2 Term 0 terminate item list IF NOT ODD SGETJPIW Itmlst THEN WRITELN error ELSE WRITELN user name is Username String END For More Information e On size attributes HP Pascal for OpenVMS Language Reference Manual 6 10 Programming on OpenVMS Systems 6 2 5 Default Parameters In some cases you do not have to supply actual parameters to correspond to all the formal parameters of a system service In HP Pascal you can supply default values for such optional parameters when you declare the service You can then omit the corresponding actual parameters from the routine call If you choose not to supply an optional parameter you should initialize the formal parameter with the appropriate value using the by immediate value IMMED mechanism The correct def
103. Repository s directory hierarchies history lists and access control lists with the Dictionary Management Utility DMU Once record paths are established you can enter data definitions into and extract them from the CDD Repository 4 8 Programming Tools To enter data definitions into the CDD Repository you first create CDD Repository source files written in the Common Data Dictionary Language CDDL The CDDL compiler converts the definitions to an internal form making them independent of the language used to access them To extract data definitions from the CDD Repository include the DICTIONARY directive in your HP Pascal source program If the data attributes of the data definitions are consistent with HP Pascal requirements the data definitions are included in the HP Pascal program during compilation The DICTIONARY directive incorporates CDD Repository data definitions into the current HP Pascal source file during compilation This directive can appear only in the TYPE section of an HP Pascal program not in the executable section For example PROGRAM SAMPLE1 TYPE SDICTIONARY Pascal SALESMAN RECORD LIST A LIST option in the DICTIONARY directive or the SHOW DICTIONARY qualifier on the Pascal command line includes the translated record in the program s listing For example TYPE SDICTIONARY PASCAL SALESMAN RECORD LIST CDD Path Name gt PASCAL SALESMAN RECORD PAYROLL RECORD PACKED RECORD SALESMAN
104. S Alpha SYSECMIS iu accu dor amp Dee ek e eye D ure wate hae Goad s s Alignment of Compiler Generated Labels Error Reduction Through Optimization Software Pipelining OpenVMS I64 and OpenVMS Alpha SVSLCMIS N T EN E OEN OET ESS T Processor Selection and Tuning OpenVMS Alpha SYSLeIiS E E E T a a ee eat a eee ee Compiling for Optimal Performance Programming Considerations llle Implementation Dependent Behavior Subexpression Evaluation Order liess MAXINT and MAXINT64 Predeclared Constants Pointer References llle eee Variant Records 22s eds oce dew ede E es Atomicity Granularity Volatility and Write Ordering Debugging Considerations l l 3 10 3 10 3 11 3 11 3 13 3 13 3 14 3 16 3 16 3 17 3 17 3 18 3 19 3 21 4 Programming Tools 4 1 Debugger Support for HP Pascal eese 4 1 4 2 Language Sensitive Editor Source Code Analyzer Support for HP Pascal sack ba ee Hs 68a ssh EERE ORES C8 ESS EE See ee eee eS 4 2 4 2 1 Programming Language Placeholders and Tokens 4 3 4 2 2 Placeholder and Design Comment Processing 4 3 4 2 3 LSE and SCA Examples 0 0 0 0 llle 4 5 4 3 Accessing CDD Repository from HP Pascal 4 8 4 3 1 Equivalent HP Pascal and CDDL Data Types 4 10 4 3 2 CDD Repository Example 0 0
105. S Alpha systems Appendix A provides a list of possible error values returned by the STATUS and STATUSV functions Appendix B provides a list of entry points to utilities in the OpenVMS Run Time Library that can be called as external routines by an HP Pascal program Appendix C provides descriptions of diagnostic messages that can be generated by an HP Pascal program at compile time and run time Related Documents The following manuals are also part of the HP Pascal documentation set HP Pascal for OpenVMS Language Reference Manual Provides information on the syntax and semantics of the HP Pascal programming language including information about the alignment allocation and internal representation of data types supported by HP Pascal HP Pascal for OpenVMS Installation Guide Provides information on how to install HP Pascal on your operating system Reader s Comments HP welcomes your comments on this manual Please send comments to either of the following addresses xii Internet openvmsdoc hp com Postal Mail Hewlett Packard Company OSSG Documentation Group ZKO3 4 U08 110 Spit Brook Rd Nashua NH 03062 2698 HP Pascal Home Page You can access the HP Pascal home page at http h71000 www7 hp com commercial pascal pascal index html Conventions The following product names may appear in this manual e HP OpenVMS Industry Standard 64 for Integrity Servers e OpenVMS I64 e 164 All three names the longer form
106. SEATTRLST Invalid use of an attribute list Error Diagnostic Messages C 27 IVUSEBNDID Illegal use of bound identifier identifier name Error An identifier that represents one bound of a conformant schema was used where a variable was expected such as in an assignment statement or in a formal VAR parameter section The restrictions on the use of a bound identifier are identical to those on a constant identifier IVUSEDES Invalid use of descriptor class attribute Error The use of an attribute on a variable parameter or routine conflicts with the requirements of the object s type IVUSEFNID Illegal use of function identifier identifier name Error Two examples of illegal uses are the assignment of values to the components of the function result if its type is structured and the passing of the function identifier as a VAR parameter IVUSEPOI Illegal use of type POINTER or UNIV PTR Error Values of type POINTER and UNIV PTR can not be dereferenced with the operator or used with the built in routines NEW and DISPOSE IVUSESIZ Invalid use of size attribute Error The use of an attribute on a variable parameter or routine conflicts with the requirements of the object s type IVUSEVISIB invalid use of visibility attribute Error The use of a visibility attribute conflicts with the requirements of the object s type KEYINTRNG KEY number must be an integer value in range 0 254 Error The key number speci
107. SRCERRORS Source errors inhibit continued compilation correct and recompile Fatal A serious error previously detected in the source program has corrupted the compiler s symbol tables and inhibits further compilation Correct the serious error and recompile the program SRCTXTIGNRD Source text following end of compilation unit ignored Warning The compiler ignores any text following the END statement that terminates a compilation unit This error probably resulted from an unmatched END statement in your program STDACTINCMP Nonstandard actual is not name compatible with other parameters in same section Information According to the Pascal standard all actual parameters passed to a parameter section must have the same type identifier or the same type definition This message is issued only if you have specified the standard switch on the compile command line C 46 Diagnostic Messages STDATTRLST Nonstandard attribute list STDBIGLABEL Nonstandard label number greater than 9999 STDBLANKPAD Nonstandard blank padding used during string operation STDBNDRMUSE Nonstandard usage of formal parameter for routine routine name STDCALLFUNC Nonstandard function function name called as a procedure STDCASLBLRNG Nonstandard label range in case selector STDCAST Nonstandard type cast operator STDCMPCOMPAT Nonstandard cannot PACK or UNPACK array component types are incompatible STDCMPDIR Nonstandard compiler dire
108. STRUCTURE Enables listing of the sizes NOSTRUCTURE LAYOUT LAYOUT record field offsets and comments about nonoptimal performance for variables and types in your program TABLE OF Enables listing of a table of NOTABLE OF CONTENTS contents only if the TITLE CONTENTS OpenVMS VAX systems only or SUBTITLE directive was specified in the source code On OpenVMS VAX systems the inline summary enabled by the SHOW INLINE qualifier shows only the names of routines that were expanded inline in the compilation If you want to know why routines were not expanded inline you must specify an additional qualifier either OPTIMIZE INLINE or OPTIMIZE ALL Although OPTIMIZE defaults to OPTIMIZE ALL you must explicitly specify the ALL option to generate these reasons Compiling HP Pascal Programs 1 19 The compiler ignores the SHOW qualifier if you do not also specify the LIST qualifier on the same command line The negation NOSHOW is equivalent to SHOW NONE SHOW is equivalent to SHOW ALL NO STANDARD NOSTANDARD default Causes the compiler to generate messages wherever the compilation unit uses HP Pascal language extensions which are nonstandard Pascal features Within the HP Pascal documentation set these standards are collectively referred to as the Pascal standard Table 1 11 lists the available options their corresponding actions and their negations Table 1 11 STANDARD Qualifier Options Option Ac
109. SYNRESWRD Syntax reserved word cannot be redefined SYNRPAREN Syntax expected SYNRPASEM Syntax 4 or expected SYNRTNTYPCNF Syntax routine heading type identifier or conformant parameter expected SYNSEMI Syntax expected SYNSEMIEND Syntax or END expected SYNSEMMODI Syntax or P expected SYNSEMRB Syntax or expected SYNSEOTEN Syntax OTHERWISE or END expected SYNTHEN Syntax THEN expected SYNTODOWN Syntax TO or DOWNTO expected SYNSEOTRP Syntax OTHERWISE or expected SYNTYPCNF Syntax type identifier or conformant parameter expected SYNTYPID Syntax type identifier expected Error The compiler either failed to find an important lexical or syntactical element where one was expected or it detected an error in such an element that does exist in your program SYNTYPPACK Only ARRAY FILE RECORD or SET types can be PACKED Warning You cannot pack any type other than the structured types listed in the message SYNTYPSPEC Syntax type specification expected SYNUNEXDECL Syntax declaration encountered in executable section SYNUNTIL Syntax UNTIL expected SYNXTRASEMI Syntax ELSE is not valid Pascal ELSE matched with IF on line line number Error The compiler either detected an error in a lexical or syntactical element in your program or it failed to find such an element where one was expect
110. TEXREQSEQ 13 Text files must have sequential organization and sequential access PAS K_TRUNOTALL 125 TRUNCATE is not allowed for a file opened for sharing PAS K_UPDNOTALL 126 UPDATE is not allowed for a file that has sequential organization PAS K_WRIINVENU 54 WRITE operation attempted on an invalid enumerated value A 4 Errors Returned by STATUS and STATUSV Functions Entry Points to HP Pascal Utilities This appendix describes the entry points to utilities in the OpenVMS Run Time Library that can be called as external routines by an HP Pascal program These utilities allow you to access HP Pascal extensions that are not directly provided by the language B 1 PASSFAB f The PAS FAB function returns a pointer to the RMS file access block FAB of file f After this function has been called the FAB can be used to get information about the file and to access RMS facilities not explicitly available in the HP Pascal language The component type of file f can be any type the file must be open PAS FAB is an external function that must be explicitly declared by a declaration such as the following TYPE Unsafe File UNSAFE FILE OF CHAR Ptr to FAB FABSTYPE FUNCTION PASSFAB VAR F Unsafe File Ptr to FAB EXTERN This declaration allows a file of any type to be used as an actual parameter to PAS FAB The type FAB TYPE is defined in the HP Pascal environment file STARLET PEN which your program or module can inheri
111. TITLE directive Source Code The source code part of a listing file includes source code line numbers LINE column a notation identifying INCLUDE directive code DICTIONARY directive code and comments IDC column a procedure nesting level PL column a statement nesting level SL column source code and diagnostic messages The following example shows several lines of a procedure accessed with an 2c INCLUDE directive on an OpenVMS VAX system On OpenVMS I64 and OpenVMS Alpha systems the format can be slightly different LINE IDC PL SL 00021 I 1 0 PROCEDURE PRINT Arr Arrtype 00022 I 1 0 VAR I INTEGER 00023 I 1 1 BEGIN Cross Reference Section The cross reference part of a listing file contains a list of all identifiers and labels used within the source code This list includes the name of the identifier or label the program element it represents the source code line numbers where it appears and where applicable the attributes declaring block and function result type associated with it Machine Code Section The machine code part of a listing file contains a representation of the object code generated by the compiler Information is organized by program section and within each program section by executable block For each program section the compiler generates the program section name and properties hexadecimal representation of the code computer generated labels symbolic opcode and symbolic o
112. V67 and EV68 EV68 processors 21264A chips This option permits the compiler to generate any EV6 instruction plus the new bit count instructions CTLZ CTPOP and CTTZ However HP Pascal does not currently generate any of the new bit count instructions and the EV67 and EV68 have identical instruction scheduling models so the EV67 and EV68 are essentially identical to the EV6 Applications compiled with this option may incur emulation overhead on EV4 EV5 EV56 and PCA56 processors Beginning with OpenVMS Alpha V7 1 and continuing with subsequent versions the operating system includes an instruction emulator This capability allows any Alpha chip to execute and produce correct results 1 6 Compiling HP Pascal Programs from Alpha instructions regardless of whether some of the instructions are not implemented on the chip Applications using emulated instructions will run correctly but may incur significant emulation overhead at run time ASSUME NOJACCURACY SENSITIVE OpenVMS 164 and Alpha systems only ASSUME ACCURACY SENSITIVE default Specifies whether certain code transformations that affect floating point operations are allowed These changes may or may not affect the accuracy of the program s results If you specify NOACCURACY SENSITIVE the compiler is free to reorder floating point operations based on algebraic identities inverses associativity and distribution This allows the compiler to move additional
113. Value Meaning PAS K ACCMETINC 5 Specified access method is not compatible with this file PAS K_AMBVALENU 30 String is an ambiguous value for the enumerated type type PAS K_CURCOMUND 73 DELETE or UPDATE was attempted while the current component was undefined PAS K_DELNOTALL 100 DELETE is not allowed for a file with sequential organization PAS K_EOF 1 File is at end of file PAS K_ERRDURCLO 16 Error occurred while the file was being closed PAS K_ERRDURDEL 101 Error occurred during execution of DELETE PAS K_ERRDUREXT 127 Error occurred during execution of EXTEND PAS K_ERRDURFIN 102 Error occurred during execution of FIND or FINDK PAS K_ERRDURGET 103 Error occurred during execution of GET PAS K_ERRDUROPE 2 Error occurred during execution of OPEN PAS K_ERRDURPRO 36 Error occurred during prompting PAS K_ERRDURPUT 104 Error occurred during execution of PUT PAS K_ERRDURRES 105 Error occurred during execution of RESET or RESETK PAS K_ERRDURREW 106 Error occurred during execution of REWRITE PAS K_ERRDURTRU 107 Error occurred during execution of TRUNCATE PAS K_ERRDURUNL 108 Error occurred during execution of UNLOCK PAS K_ERRDURUPD 109 Error occurred during execution of UPDATE PAS K_ERRDURWRI 50 Error occurred during execution of WRITELN PAS K_EXTNOTALL 128 EXTEND is not allowed for a shared file PAS K_FAIGETLOC 74 GET failed to retrieve a locked component PAS K_FILALRCLO 15 File is already closed PAS K
114. Y 1 15 MULTILANGUAGE 1 18 OBJECT 1 16 OPTIMIZE 1 16 OPTIONS 1 35 PLATFORMS 1 18 SHAREABLE 1 35 SHOW 1 19 STANDARD 1 20 SYNCHRONOUS EXCEPTIONS 1 21 TERMINAL 1 21 Qualifiers cont d TIE 1 21 TRACEBACK 1 35 USAGE 1 22 VERSION 1 25 WARNINGS 1 25 with LINK command 1 33 to 1 35 with PASCAL command 1 3 to 1 25 with RUN command 1 37 ZERO HEAP 1 25 R RAB access to B 2 fields when calling OPEN 7 7 passed as parameter by run time library 7 10 used to write user action functions 7 1 READONLY attribute on pointer variables 3 17 with system services 6 9 Read sharing 7 14 Record efficient use of nonstatic fields 3 15 locking 7 15 variant example 2 12 Record access block See RAB Record file address See RFA Record layout overview 9 3 Record Management Services See RMS 7o REF specifier on actual parameters 6 17 Register assignment of variables to 3 2 contents saved by routine call 5 5 effects of optimization 3 21 Relative file locked component in 7 15 REPEAT statement effect on efficiency 3 14 Resignal definition of 8 2 Resultant_Filespec parameter of LIB FIND_ FILE 6 17 Return value function 5 2 REVERT procedure 8 5 RFA random access by 7 3 RMS file sharing capability 7 14 locking components with 7 15 used to perform I O tasks 7 1 to 7 16 Routine T O processing 7 1 to 7 16 requirements for linking modules 2 2 using foreign mechanisms
115. _FILALROPE 1 File is already open PAS K_FILNAMREQ 14 File name must be specified in order to save print or submit an internal file continued on next page A 2 Errors Returned by STATUS and STATUSV Functions Table A 1 Cont STATUS and STATUSV Return Values Name Value Meaning PAS K_FILNOTDIR 110 File is not open for direct access PAS K_FILNOTFOU 3 File was not found PAS K_FILNOTGEN 111 File is not in generation mode PASS K FILNOTINS 112 File is not in inspection mode PAS K FILNOTKEY 113 File is not open for keyed access PAS K_FILNOTOPE 114 File is not open PAS K_FILNOTSEQ 115 File does not have sequential organization PAS K_FILNOTTEX 116 File is not a text file PAS K_GENNOTALL 117 M mode is not allowed for a read only e PAS K GETAFTEOF 118 GET attempted after end of file has been reached PAS K INSNOTALL 119 MEE mode is not allowed for a write only e PAS K_INSVIRMEM 120 Insufficient virtual memory PAS K_INVARGPAS 121 Invalid argument passed to an HP Pascal Run Time Library procedure PAS K_INVFILSYN Invalid syntax for file name PAS K_INVKEYDEF 9 Key definition is invalid PAS K_INVRECLEN 12 Record length nnn is invalid PAS K_INVSYNBIN 37 String is invalid syntax for a binary value PAS K_INVSYNENU 31 String is invalid syntax for a value of an enumerated type PAS K_INVSYNHEX 38 String is invalid syntax for a hexadecimal value PAS K_INVSYNINT 32 String is invalid
116. a type of key XAB B FLG Key option flags XAB V CHG Changes allowed 0 if key is 0 else 1 XAB V DUP Duplicates allowed 0 if key is 0 else 1 XAB W POSO Key position Position of key in indexed file XAB B REF Key of reference Primary key is 0 first alternate key is 1 second alternate key is 2 and so on XAB B SIZO Key size Size of key Table 7 5 presents the status of RMS Name Block fields when you call the OPEN procedure If a field is not included in the following table it is initialized to zero Input and Output Processing 7 9 Table 7 5 Setting of Name Block Fields by a Call to the OPEN Procedure Field Name OPEN Keyword and Value NAM L ESA Expanded string area Address of RTL buffer NAM B ESS Expanded string area NAM C MAXRSS NAM L RSA Expanded string area Address of RTL buffer NAM B RSS Expanded string area NAM C_MAXRSS These fields are only valid during execution of user action functions HP Pascal places 0 in these fields after the call to OPEN For More Information e On opening indexed files Section 7 1 1 7 1 7 Default Line Limits HP Pascal determines a default line limit for TEXT files by translating the logical name PAS LINELIMIT as a string of decimal digits If this logical name has not been defined there is no default line limit You can override the default by calling the LINELIMIT procedure For More Information On LINELIMIT HP Pascal for OpenVMS Language Reference Manual 7 2 User Act
117. ach formal parameter except one with the LIST attribute can have only one corresponding actual parameter C 2 Diagnostic Messages ACTPASCNVTMP Conversion actual passed is resulting temporary ACTPASRDTMP Formal requires read access actual parameter is resulting temporary ACTPASSIZTMP Size mismatch actual passed is resulting temporary ACTPASWRTMP Formal requires write access actual parameter is resulting temporary Warning A temporary variable is created if an actual parameter does not have the size type and accessibility properties required by the corresponding foreign formal parameter ACTPRMORD Actual parameter must be ordinal Error The actual parameter that specifies the starting index of an array for the PACK or UNPACK procedure must have an ordinal type ADDIWRDALIGN ADD INTERLOCKED requires variable with at least word alignment ADDIWRDSIZE ADD INTERLOCKED requires 16 bit variable Error These restrictions are imposed by the instruction sequence that is used on the target architecture ADDRESSVAR parameter name is a VAR parameter ADDRESS is illegal Warning You should not use the ADDRESS function on a nonvolatile variable or component or on a formal VAR parameter ADISCABSENT Formal discriminant discriminant name has no correspond ing actual discriminant Error An actual discriminant must be specified for every formal discriminant in a schema type definition ADISCHASNOFRML Actual discriminant h
118. alifier PREREQPRMLST Passing predeclared routine name requires formal to include parameter list Error To pass one of the predeclared routines EXPO ROUND TRUNC UNDEFINED UTRUNC UROUND DBLE SNGL QUAD INT ORD and UINT as an actual parameter to a routine you must specify a formal parameter list in the corresponding formal routine parameter PRMKWNSIZ Parameter must have a size known at compile time Error The BIN HEX OCT DEC and UDEC functions cannot be used on conformant parameters The SIZE and NEXT functions cannot be used on conformant parameters in compile time constant expressions PROCESSFILE Compiling file file name Information PROCESSRTN Generating code for routine routine name Information PROGSCHENV PROGRAM with schema may not create environment Error A program that declares a schema type cannot have the ENVIRONMENT attribute Schema declarations should be placed in a separate module and inherited by the program C 40 Diagnostic Messages PROPRMEXT Declaration of program parameter name is EXTERNAL program parameter files must be locally allocated PROPRMFIL A program parameter must be a variable of type FILE PROPRMINH Declaration of program parameter name is inherited program parameter files must be locally allocated PROPRMLEV Program parameter program parameter name is not declared as a variable at the outermost level Error Any external file variable other th
119. ally read and the record number in which this text occurred User Action Correct the program or the input data so that the correct syntax is used See the HP Pascal for OpenVMS Language Reference Manual for more information INVSYNREA string is invalid syntax for a real value Explanation While a READ or READV procedure was reading a value for a real identifier from a text file the characters read did not conform to the syntax for a real value The displayed message includes the text actually read and the record number in which this text occurred User Action Correct the program or the input data so that the correct syntax is used See the HP Pascal for OpenVMS Language Reference Manual for more information INVSYNUNS string is invalid syntax for an unsigned value Explanation While a READ or READV procedure was reading a value for an unsigned identifier from a text file the characters read did not conform to the syntax for an unsigned value The displayed message includes the text actually read and the record number in which this text occurred User Action Correct the program or the input data so that the correct syntax is used See the HP Pascal for OpenVMS Language Reference Manual for more information KEYCHANOT key field change is not allowed Explanation Your program attempted an UPDATE procedure for a record of an indexed file that would have changed the value of a key field and this situation was disallow
120. ameters For conformant varying parameters HP Pascal uses a CLASS VS desciptor For conformant array parameters HP Pascal uses a CLASS NCA descriptor on OpenVMS I64 and OpenVMS Alpha systems and a CLASS A descriptor on OpenVMS VAX systems 5 18 Calling Conventions Using a conformant varying parameter or STRING schema parameter with a routine not written in Pascal is not very common since the called routine does not know how to deal with these strings If you just are passing a string expression to the non Pascal routine using a conformant PACKED ARRAY OF CHAR is the right solution Since HP Pascal will use either a CLASS A or CLASS NCA descriptor for the conformant PACKED ARRAY OF CHAR but other languages will expect either a CLASS S descriptor or the string by reference you will need to use either the CLASS 5 attribute or the REF foreign mechanism specifier For example to pass a string expression to Fortran which expects a CLASS S descriptor external procedure fortrtn p class s packed array l u integer of char external begin fortrtn string fortrtn some string expression end To pass a string expression to C which expects a by reference parameter and a null terminated string external procedure crtn ref p packed array l u integer of char external begin crtn string 0 crtn some string expression 0 end HP Pascal on OpenVMS 164 and OpenVMS Alpha systems has additional
121. an INPUT and OUTPUT that is listed in the program heading must also be declared as a file variable in a VAR section in the program block PSECTMAXINT Allocation of symbol name causes PSECT PSECT name to exceed MAXINT bits Error The HP Pascal implementation restricts the size of a program section to 2 147 483 647 bits PTRCMPEQL Pointer values may only be compared for equality Error The equality and inequality lt gt operators are the only operators allowed for values of a pointer type all other operators are illegal PTREXPRCOM Pointer expressions are not compatible Error The base types of two pointer expressions being compared for equality or inequality lt gt are not structurally compatible QUOBEFEOL Quoted string not terminated before end of line Error QUOSTRING Quoted string expected Error The compiler expects the DICTIONARY and INCLUDE directives and the radix notations for binary B hexadecimal X and octal constants 0 to be followed by a quoted string of characters RADIXTEXT Radix input requires FILE VARIABLE of type TEXT Error The input radix specifiers BIN OCT and HEX operate only on text files READONLY variable name is READONLY Warning You cannot use a read only variable in any context that would store a new value in the variable For example a read only variable cannot be used in a file operation Diagnostic Messages C 41 REALCNSTRNG Real constant ou
122. and line C 54 Diagnostic Messages STDVRNTONSTR Nonstandard variant field outside constructor variant part Information This message refers to the use of an extension to Pascal This message is issued only if you have specified the extended argument to the standard switch the compile command line STDVRNTPART Nonstandard empty variant part Information According to the Pascal standard a variant part that declares no case labels and field lists between the words OF and END is illegal This message occurs only if you have specified the standard switch on the compile command line STDVRNTRNG Nonstandard variant labels do not cover the range of the tag type Information According to the Pascal standard you must specify one case label for each value in the tag type of a variant record This message is issued only if you have specified the standard switch on the compile command line STDWRTBIN Nonstandard binary output to a TEXT file STDWRTENUM Nonstandard user defined enumerated type output to a TEXT file STDWRTHEX Nonstandard hexadecimal output to a TEXT file STDWRTOCT Nonstandard octal output to a TEXT file Information The Pascal standard allows only INTEGER BOOLEAN CHAR REAL and PACKED ARRAY 1 n OF CHAR values to be written to a text file The ability to write values of other types is an extension to Pascal These messages are issued only if you have specified the standard switch on the compile command line
123. and perform the division at compile time The compiler treats the assignments as if they were as follows Pi 3 14 Pi Over 2 1 57 This process is repeated allowing for further constant propagation to occur e It allows comparisons and branches to be avoided at run time For example X 2 34 IF x lt gt 3 THEN y 30 ELSE y 20 In a program that includes these operations the compiler recognizes that the value of x is 3 and the THEN statement cannot be reached The compiler will generate code as if the statements were written as follows 3 2 x i ys 0 Strength Reduction OpenVMS 164 and OpenVMS Alpha systems Strength reduction speeds computations by replacing a multiply operation with a more efficient add instruction when computing array addresses each time around a loop Split Lifetime Analysis OpenVMS 164 and OpenVMS Alpha systems Split lifetime analysis improves register usage by determining if the lifetime of a variable can be broken into multiple independent sections If so the variable may be stored in different registers for each section The registers can then be reused for other purposes between sections Therefore there may be times when the value of the variable does not exist anywhere in the registers For example Program Correctness Optimization and Efficiency 3 9 3 1 13 3 1 14 v 3 0 q x SIN y v vi PI x y COS y v This example shows that the variable v has tw
124. andling routines User Action Modify your program so that it does not try to use files that may currently be in use FILALRCLO file is already closed Explanation Your program attempted to close a file that was already closed User Action Modify your program so that it does not try to close files that are not open FILALROPE file is already open Explanation Your program attempted to open a file that was already open User Action Modify your program so that it does not try to open files that are already open FILNAMREQ FILE NAME required for this HISTORY or DISPOSITION Explanation Your program attempted to open a nonexternal file without specifying a file name parameter to the OPEN procedure but the HISTORY or DISPOSITION parameter specified requires a file name User Action Add a file name parameter to the OPEN procedure call specifying an appropriate file name FILNOTDIR file is not opened for direct access Explanation Your program attempted to execute a DELETE FIND LOCATE or UPDATE procedure on a file that was not opened for direct access User Action Modify the program to specify the ACCESS METHOD DIRECT parameter to the OPEN procedure when opening the file See Chapter 7 to determine if direct access is appropriate for your application Diagnostic Messages FILNOTFOU file not found Explanation Your program attempted to open a file that does not exist An additional RMS message is displayed tha
125. antics Actual Parameter Variable Variable or Expression No VAR VAR No VAR VAR Passing Mechanism on Formal on Formal on Formal on Formal By immediate value IMMED or Foreign Error Foreign Error IMMEDIATE By reference Default for non Value Variable Value Value conformant or nonschema REF or Variable Error Foreign Error REFERENCE By descriptor Default for Value Variable Value Value conformant and schema CLASS S Value Variable Value Value CLASS A Value Variable Value Value CLASS NCA Value Variable Value Value STDESCR Variable Error Foreign Error DESCR Variable Error Foreign Error 1If the formal parameter is declared with the READONLY attribute then value passing semantics is used otherwise it is an error 5 4 Passing Parameters between HP Pascal and Other Languages Passing parameters between HP Pascal and other languages on OpenVMS systems requires some additional knowledge about the semantics and mechanisms used by the HP Pascal and the other compilers involved 5 4 1 Parameter Mechanisms Versus Parameter Semantics The Pascal language provides three parameter semantics VAR parameters value parameters and routine parameters These models define what happens to the parameters not how the compiler actually implements them VAR parameters are parameters that represent the actual variable passed to the routine Changes made to the VAR parameter are reflected back to the
126. as no corresponding formal discriminant Error The number of actual discriminants specified is greater than the number of formal discriminants defined in the schema type definition AGGNOTALL Aggregate variable access of this type not allowed must be indexed Error ALIATRTYPCON Alignment attribute type conflict Diagnostic Messages C 3 ALIGNAUTO Alignment greater than n conflicts with automatic allocation Error The value n has the value 4 on OpenVMS 164 3 on OpenVMS Alpha and 2 on OpenVMS VAX OpenVMS I64 systems align the stack on an octaword boundary OpenVMS Alpha systems align the stack on a quadword boundary OpenVMS VAX systems align the stack on a longword boundary You cannot specify a greater alignment for automatically allocated variables ALIDOWN Alignment down graded from default of ALIGNED n Info The value of n is based on the size of the object that is being downgraded ALIGNFNCRES Alignment greater than n not allowed on function result Error The value n has the value 4 on OpenVMS 164 systems 3 on OpenVMS Alpha systems and 2 on OpenVMS VAX systems The use of an attribute on a routine conflicts with the requirements of the object s type ALIGNINT ALIGNED expression must be integer value in range 0 n defaulting to m Error The value n has the value of the largest argument to the ALIGNED attribute allowed on the platform ALIGNVALPRM Alignment greater than n not allowed on value parameter
127. as specified at compile time Error The specified INCLUDE module could not be accessed because a text library was not specified on the command line or in the PASCAL LIBRARY logical name NOTSAMTYP Not the same type NOTUNBOUND routine name is not UNBOUND Information These messages can appear as additional information on other error messages NOTSCHEMA symbol name is not a schema type Error NOTVARNAM Parameter to this predeclared function must be simple variable name Error The parameter cannot be indexed be dereferenced have a field selected or be an expression It must be the name of the entire variable NOTVOLATILE variable name is non VOLATILE Warning You should not use the ADDRESS function on a nonvolatile variable or component or on a formal VAR parameter NOUNSATDECL No unsatisfied declaration of label label name in block name Error C 36 Diagnostic Messages NUMFRMLPARM Different numbers of formal parameters Information This message can appear as additional information on other error messages NXTACTDIFF NEXT of actual s component differs from that of other parameters in same section Error All actual parameters passed to a formal parameter section whose type is a conformant schema must have identical bounds and be structurally compatible This message refers to the allocation size and alignment of the array s inner dimensions OLDDECLSYN Obsolete routine para
128. at a cost of additional code size However larger numbers may decrease performance due to cache requirements register conflicts and other factors Alignment of Compiler Generated Labels The compiler aligns the labels it generates for the top of loops the beginnings of ELSE branches and others on machine specific boundaries by filling in unused bytes with NO OP instructions A branch to a longword aligned address is faster than a branch to an unaligned address This optimization may increase the size of the generated code however it increases run time speed Error Reduction Through Optimization An optimized program produces results and run time diagnostic messages identical to those produced by an equivalent unoptimized program An optimized program may produce fewer run time diagnostics however and the diagnostics may occur at different statements in the source program For example Unoptimized Code Optimized Code a x y t x y b x y a t FOR i 1 TO 10 DO b t cli cli x y FOR i 1 TO 10 DO cli eli t If the value of y is 0 0 the unoptimized program would produce 12 divide by zero errors at run time the optimized program produces only one The variable t is a temporary variable created by the compiler Eliminating redundant calculations and removing invariant calculations from loops can affect the detection of such arithmetic errors You should keep this in mind when you includ
129. ault size for enumerations and Booleans in unpacked structures is longword on OpenVMS I64 and OpenVMS Alpha systems On OpenVMS VAX systems the default size is byte for Booleans and small enumerations or words for larger enumerations If you need the OpenVMS VAX behavior on OpenVMS I64 or OpenVMS Alpha systems you can use one of the following e ENUMERATION_SIZE BYTE qualifier Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha 9 1 e ENUMERATION SIZE BYTE attribute e Individual BYTE or WORD attributes on the affected fields or components The default for OpenVMS VAX compilers is ENUMERATION SIZE BYTE for compatibility 9 3 Default Data Layout for Unpacked Arrays and Records On OpenVMS I64 and OpenVMS Alpha systems the default data layout is natural alignment where record fields and array components are aligned on boundaries based on their size for example INTEGERs on longword boundaries INTEGER64s on quadword boundaries On OpenVMS VAX systems the default alignment rule is to allocate such fields on the next byte boundary If you need the OpenVMS VAX behavior on OpenVMS I64 or OpenVMS Alpha systems you can use the ALIGN VAX qualifier or the ALIGN VAX attribute 9 4 Overflow Checking When overflow checking is enabled on OpenVMS 164 and OpenVMS Alpha systems the INT built in signals a run time error if its actual parameter cannot be represented as an INTEGER32 value If you have a large unsi
130. ault value is usually 0 For example the Cancel Timer SYS CANTIM system service has two optional parameters If you do not specify values for them in the actual parameter list you must initialize them with zeros when they are declared The following example is the routine declaration for SYS CANTIM SIMMED REQIDT UNSIGNED IMMED 0 ASYNCHRONOUS EXTERNAL SYS CANTIM FUNCTION CANTIM IMMED ACMODE UNSIGNED IMMED 0 INTEGER EXTERNAL A call to CANTIM must indicate the position of omitted parameters with a comma unless they all occur at the end of the parameter list For example the following are legal calls to CANTIM using the previous external declaration SCANTIM PSL C USER SCANTIM I CANTIM PSL C USER is a symbolic constant that represents the value of a user access mode and I is an integer that identifies the timer request being canceled If you call CANTIM with both of its default parameters you can omit the actual parameter list completely When it is possible for the parameter list to be truncated you can also specify the TRUNCATE attribute on the formal parameter declaration of the optional parameter The TRUNCATE attribute indicates that an actual parameter list for a routine can be truncated at the point that the attribute was specified However once one optional parameter is omitted in the actual parameter list it is not possible to specify any optional parameter following that For exam
131. be of type TEXT Error The EOLN function requires that its parameter be a file of type TEXT VARPRMRTN Formal VAR parameter may not be a routine Error The reserved word VAR cannot precede the word PROCEDURE or FUNCTION in a formal parameter declaration VARPTRTYP Variable must be of a pointer type Error The NEW and DISPOSE procedures operate only on pointer variables VARYFLDS LENGTH and BODY are the only fields in a VARYING type Error You cannot use the syntax Variable Identifier to specify any fields of a VARYING OF CHAR variable other than LENGTH and BODY VISAUTOCON Visibility AUTOMATIC allocation conflict Error The GLOBAL EXTERNAL WEAK GLOBAL and WEAK EXTERNAL attributes require static allocation and therefore conflict with the AUTOMATIC attribute VISGLOBEXT Visibilities are not GLOBAL EXTERNAL or EXTERNAL EXTERNAL Information In repeated declarations of a variable or routine only one declaration at most can be global all others must be external This message can appear as additional information for other error messages VRNTRNG Variant labels do not cover the range of the tag type Error According to the Pascal standard you must specify one case label for each value in the tag type of a variant record or include an OTHERWISE clause WDTHONREAL Second field width is allowed only when value is of a real type Error The fraction value in a field width specification is allowed only for real nu
132. begin END END Example 2 3 shows a main program and its use of the types and routines provided by the interface module Example 2 3 A Graphics Main Program Source File graphics main program pas This program inherits the interface environment file which gives it access to the implementation s declarations INHERIT Interface Types and routines in interface module PROGRAM Graphics Main Program OUTPUT VAR My Shape Shape Rectangle VALUE Coordinate X 25 0 Coordinate Y 25 0 CASE Rectangle OF Height 12 50 Width 25 63 BEGIN You cannot access the variable Initial Shape because it is in the implementation module and that module does not create an environment file continued on next page 2 18 Separate Compilation Example 2 3 Cont A Graphics Main Program You can work with My Shape If you did not provide initial values in this declaration section the module Graphics Interface provided initial values for the schema type Shape Draw My Shape Scale My Shape Rotate My Shape Delete My Shape END js hs To compile link and run the code in Examples 2 1 2 2 and 2 3 enter the following PASCAL GRAPHICS INTERFACE PASCAL GRAPHICS IMPLEMENTATION PASCAL GRAPHICS MAIN PROGRAM LINK GRAPHICS MAIN PROGRAM GRAPHICS IMPLEMENTATION _S GRAPHICS INTERFACE RUN GRAPHICS MAIN PROGRAM Drawing a company logo Code that draws a circle Deleting the shape
133. behavior you may not need the OBJ file created when generating a PEN file however if the module is used inherited variables or routines then the OBJ file is needed at link time This applies not only to the environments inherited by the program but also to any environments inherited by modules which create subsequent environments With the addition of schema types and TO BEGIN DO and TO END DO sections the decision on which OBJ files to include on the LINK command becomes more complicated This is due to e The compiler generated variables and routines for schema types e Any module initialization or finalization sections TO BEGIN DO and TO END DO sections e The fact that currently PROGRAMS that inherit modules with initialization routines do not call the module s initialization routines directly but rely on the OpenVMS LIB INITIALIZE feature to activate them 2 6 Separate Compilation The rule is still basically Use any OBJ whose module contained variables or routines but now you must consider compiler generated variables or routines as well as user defined variables or routines Depending on the modules involved missing OBJ files might not be detected by the linker since PROGRAMS do not directly call their inherited initialization routines Compiling with the DEBUG qualifier might require more OBJ files to be included on the LINK command Normally the compiler only uses the inherited compiler generated variables and routines
134. ber My Handler SS CONTINUE END Handle the reserved operand left by SORT SS ROPRAND BEGIN WRITELN Outfile Reserved floating operand LIBSFIXUP_FLT Sigargs Mechargs My Handler SS CONTINUE END OTHERWISE BEGIN WRITELN Outfile Condition occurred HEX Sigargs 1 My Handler SS RESIGNAL END END CLOSE Outfile END ESTABLISH My Handler s 1E38 Generate exception conditions F2 0 0 F2 f2 SORT 1 0 8 16 Error Processing and Condition Handling 9 Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha This chapter provides information on issues that affect programs being moved from OpenVMS VAX systems to OpenVMS I64 or OpenVMS Alpha systems e Section 9 1 Sharing Environment Files Across Platforms e Section 9 2 Default Size for Enumerated Types and Booleans e Section 9 3 Default Data Layout for Unpacked Arrays and Records e Section 9 4 Overflow Checking e Section 9 5 Bound Procedure Values e Section 9 6 Different Descriptor Classes for Conformant Array Parameters e Section 9 7 Data Layout and Conversion 9 1 Sharing Environment Files Across Platforms HP Pascal inherits environment files created from a compiler for the same target platform For example you cannot inherit environment files generated by VAX Pascal with the HP Pascal compiler for OpenVMS 164 or OpenVMS Alpha systems 9 2 Default Size for Enumerated Types and Booleans The def
135. called routine does not write the input data Thus input data supplied by a variable is preserved when the called routine completes execution e Write only data that the called routine returns to the calling routine must be written into a location where the calling routine can access it Such data can be thought of as output data The called routine does not read the contents either before or after it writes into the location 6 6 Programming on OpenVMS Systems e Modify a parameter specifies data that is both read and written by the called routine In this case the called routine reads the input data which it uses in its operations and then overwrites the input data with the results Thus when the called routine completes execution the input data specified by the argument is lost Table 6 2 lists all access methods that may appear under the access entry in a parameter description as well as the HP Pascal translation Table 6 2 Access Type Translations Access Entry Method Used in HP Pascal Call after stack unwind Procedure or function parameter passed by immediate value Function call before return Function parameter Jump after unwind Not available Modify Variable semantics Read only Value or foreign semantics Call without stack unwind Procedure parameter Write only Variable semantics 1Tt is possible to obtain variable semantics by either specifying the VAR keyword on the formal parameter or by passing a
136. casionally a condition handler may require a particular condition to be identified by an exact match that is each bit of the condition value bits 0 31 must match the specified condition For example you may want to process a floating overflow condition only if the severity code is still 4 that is if no previous condition handler has changed the severity code and the control bits have not been modified A typical condition handler response is to change the severity code and resignal In most cases however you want some response to a condition regardless of the value of the severity code or control bits To ignore the severity and control fields of a condition value declare and call the LIBSBMATCH COND function 8 8 Error Processing and Condition Handling 8 3 5 Using Condition Handlers that Return SS CONTINUE HP Pascal condition handlers can do one of the following after appropriately responding to the error e Use a nonlocal GOTO to transfer control to a label in an enclosing block e Return SS CONTINUE if the handler is conditioned to dismiss the error then signal to continue processing e Return SS _RESIGNAL if the handler is conditioned to continue searching for additional handlers to call e Call the UNWIND system service to establish a new point to resume execution when the handler returns to the system When an exception occurs the system calls a handler in the Pascal Run Time Library that is established by the gene
137. ce passing mechanism NOTBERODES May not be passed as a READONLY descriptor foreign parameter NOTBEROFOR May not be passed as a READONLY reference foreign parameter NOTBEROVAR May not be passed as a READONLY VAR parameter NOTBETOUCH May not be read modified written ZZ NOTBEVAR May not be passed as a VAR parameter NOTBEWODES May not be passed as a WRITEONLY descriptor foreign parameter NOTBEWOFOR May not be passed as a WRITEONLY reference foreign parameter NOTBEWOVAR May not be passed as a WRITEONLY VAR parameter NOTBEWRTV May not be parameter to WRITEV Information These messages can appear as additional information on other error messages NOTBYTOFF Field field name is not aligned on a byte boundary Error Diagnostic Messages C 35 NOTDECLROU symbol name is not declared as a routine NOTINITIAL routine name is not INITIALIZE Information These messages can appear as additional information on other error messages NOTINRNG Value does not fall within range of the tag type Error The value specified as the case label of a variant record is not a legal value of the tag field s type This message is also issued if a case label in a call to NEW DISPOSE or SIZE falls outside the range of the tag type NOTNEWTY P Schema must define a new type Error The type denoter of a schema definition must define a new type for example a subrange an array or a record NOTXTLIB No text library w
138. chanism must be UNBOUND Asynchronous system trap routines ASTs and RMS completion routines must have both the ASYNCHRONOUS and UNBOUND attributes Because they are asynchronous such routines can access only volatile variables predeclared routines and other asynchronous routines Note that the HP Pascal run time system does not permit a program and an asynchronous routine such as an AST to access the same file simultaneously For More Information e On attributes HP Pascal for OpenVMS Language Reference Manual e On the immediate value mechanism Section 5 3 1 5 2 Parameter Passing Semantics Parameter passing semantics describe how parameters behave when passed between the calling and called routine HP Pascal passes parameter values by the following methods e Value passing semantics Standard e Variable passing semantics Standard 5 6 Calling Conventions e Foreign passing semantics HP Pascal extension By default HP Pascal passes arguments using value semantics For More Information e On value variable and foreign semantics HP Pascal for OpenVMS Language Reference Manual 5 3 Parameter Passing Mechanisms The way in which an argument specifies how the actual data to be passed by the called routine is defined by the parameter passing mechanism In compliance with the OpenVMS calling standard HP Pascal supports the basic parameter passing mechanisms shown in Table 5 1 Table 5 1 Parameter Passing Descript
139. cludes the following e Modifications to the FAB or RAB or both optional e OPEN and CONNECT for existing files or CREATE and CONNECT for new files required e Status check of the values returned by OPEN or CREATE and CONNECT required e Storage of FAB and RAB values in program variables optional e Return of success or failure status value for the user action function required Note Modification of any of the RMS file access blocks provided by the run time library may interfere with the normal operation of the library Example 7 1 shows an HP Pascal program that copies one file into another The program features two user action functions which allow the output file to be created with the same size as the input file and to be given contiguous allocation on the storage media Input and Output Processing 7 11 Example 7 1 User Action Function INHERIT SYSSLIBRARY STARLET PROGRAM Contiguous Copy F In F Out The input file F In is copied to the output file F Out F Out has the same size as F In and has contiguous allocation TYPE FType FILE OF VARYING 133 OF CHAR VAR F In F Out FType Alloc Quantity UNSIGNED FUNCTION User Open VAR FAB FABSTYPE VAR RAB RABSTYPE VAR F FType INTEGER VAR Status INTEGER BEGIN Function User Open Open file and remember allocation quantity Status SOPEN FAB IF ODD Status THEN Status SCONNECT RAB Al
140. ct the program or the input data so that the correct syntax is used See the HP Pascal for OpenVMS Language Reference Manual for more information INVSYNENU string is invalid syntax for an enumerated value Explanation While a READ or READV procedure was reading an identifier of an enumerated type from a text file the characters read did not conform to the syntax for an enumerated value The displayed message includes the text actually read and the record number in which this text occurred User Action Correct the program or the input data so that the correct syntax is used See the HP Pascal for OpenVMS Language Reference Manual for more information INVSYNINT string is invalid syntax for an integer value Explanation While a READ or READV procedure was reading a value for an integer identifier from a text file the characters read did not conform to the syntax for an integer value The displayed message includes the text actually read and the record number in which this text occurred User Action Correct the program or the input data so that the correct syntax is used See the HP Pascal for OpenVMS Language Reference Manual for more information C 78 Diagnostic Messages INVSYNOCT string is invalid syntax for an octal value Explanation While a READ or READV procedure was reading an octal value from a text file the characters read did not conform to the syntax for an octal value The displayed message includes the text actu
141. ctive STDCOMFUNACC Nonstandard component function access STDCNFARR Nonstandard conformant array syntax Information These messages refer to extensions to Pascal and are issued only if you have specified the standard switch on the compile command line STDCNSTR Nonstandard array or record constructor Information A VAX Pascal Version 1 0 style constructor was used You should convert this constructor to the new constructor syntax provided in the current version of HP Pascal to be compatible with the Extended Pascal standard STDCONCAT Nonstandard concatenation operator Information This message refers to extensions to Pascal and is issued only if you have specified the standard switch on the compile command line STDCONST Nonstandard type name constant Information Binary hexadecimal and octal constants and constants of type DOUBLE QUADRUPLE UNSIGNED INTEGER64 and UNSIGNED64 are extensions to Pascal This message is issued only if you have specified the standard switch on the compile command line STDCONSTACC Nonstandard structured constant access Information This message is issued if you have specified a standard option other than extended on the compile command line Diagnostic Messages C 47 STDCTLDECL Nonstandard control variable variable name not declared in VAR section of block name Information The Pascal standard requires that the control variable of a FOR statement be declared i
142. ctures 7 5 to 7 10 with user action parameters 7 10 OpenVMS programming attributes used during 6 14 Operation optimization of 3 7 Operator type cast use with CDD Repository 4 10 use with debugger 4 2 Optimal performance 3 13 compiling for 3 13 Optimization 1 16 3 1 code scheduling 3 10 definition of 3 1 effect on debugging 3 21 kinds of 3 2 loop unrolling 3 10 Optimization cont d reducing errors through 3 11 split lifetime analysis 3 9 strength reduction 3 9 OPTIMIZE attribute C 25 OPTIMIZE qualifier 1 16 OPTIONS qualifier with LINK command 1 35 OTHERWISE reserved word initializing an array example 2 1 Overflow run time checking of 1 7 Overflow checking effect on efficiency 3 15 Overview of record layout 9 3 P PACKED ARRAY OF CHAR type as function result type 5 3 Parameter ASTADR parameter 6 16 ASTPRM parameter 6 17 data structure 6 9 default value for 6 11 descriptors 5 9 for condition handler 8 6 of LIBBFIND FILE 6 17 of SYS QIO SYS QIOW and SYS FAO 6 17 passing to run time library routines 6 12 passing to system services 6 8 using foreign mechanisms on actual parameters 6 16 Parameter list 5 2 of arbitrary length 6 12 Parameter passing semantics 5 6 Parentheses effect on efficiency 3 14 PAS FAB function B 1 PAS LINELIMIT logical name 7 10 PAS MARK2 function B 2 Index 7 PAS RAB function B 2 PAS RELEASE2 function B 3
143. d INPUT or OUTPUT identifiers e Variables that have global external or inherited visibility e Variables declared with the AT attribute e Variables declared with the COMMON attribute e Variables declared with the READONLY attribute e Variables declared with the VOLATILE attribute e Variables used as parameters e Variables used as function identifiers The USAGE qualifier without options is equivalent to USAGE ALL The negation NOUSAGE is equivalent to USAGE NONE The HP Pascal compiler can detect when some variables are uninitialized however it cannot detect that an uplevel variable is uninitialized at the point at which it was referenced This is because at the time the routine is lexically scanned the compiler has not seen any of the calls to that routine 1 24 Compiling HP Pascal Programs NO VERSION NOVERSION default Controls whether the compiler prints compiler and OpenVMS version information to SYS OUTPUT and then returns to the operating system No other command qualifiers or source files are processed when VERSION is used NO WARNINGS WARNINGS default Directs the compiler to generate diagnostic messages in response to warning level or informational level errors By default these messages are written to the error file SYS ERROR A warning or informational diagnostic message indicates that the compiler has detected acceptable but unorthodox syntax or has performed some corrective action in either
144. d M OBJ and a listing file named M LIS The compiler places the object and listing files in the default directory PASCAL LIST A B C Source files A PAS B PAS and C PAS are compiled as separate files producing object files named A OBJ B OBJ and C OBJ and listing files named A LIS B LIS and C LIS PASCAL X Y Z Source files X PAS Y PAS and Z PAS are concatenated and compiled as one file producing an object file named X OBJ By default batch mode produces a listing file which takes its name from the name of the first file on the command line In this example the name of the listing file would be X LIS PASCAL A B C D LIST F When a qualifier follows the file specification it applies only to the file immediately preceding it Files concatenated with plus signs are considered one file This command line produces four object files A OBJ B OBJ C OBJ and F OBJ and one listing file D LIS PASCAL A CIRC NOOBJECT X This command completely suppresses the object file that is source files A PAS CIRC PAS and X PAS are concatenated and compiled but no object file is produced 1 1 2 PASCAL Qualifiers This section describes the command and file qualifiers that you can use when compiling code ALIGN keyword Controls the default alignment rules Note that specifying the ALIGN attribute overrides any value that was previously specified for the ALIGN qualifier Compiling HP Pascal Programs 1 3 Tabl
145. d at run time C 1 Compiler Diagnostics The HP Pascal compiler reports compile time diagnostics in the source listing Gf one is being generated and summarizes them on the terminal in interactive mode or in the batch log file in batch mode Compile time diagnostics are preceded by the following I PASCAL W E F Table C 1 shows the severity level indicated by each letter Table C 1 Compiler Message Warning Levels Letter Meaning I An informational message that flags extensions to the Pascal standard identifies unused or possibly uninitialized variables or provides additional information about a more severe error W A warning that flags an error or construct that may cause unexpected results but that does not prevent the program from linking and executing E An error that prevents generation of machine code instead the compiler produces an empty object module indicating that E level messages were detected in the source program F A fatal error If the source program contains either E or F level messages the errors must be corrected before the program can be linked and executed Diagnostic Messages C 1 All diagnostic messages contain a brief explanation of the event that caused the error This section lists compile time diagnostic messages in alphabetical order including their severity codes and explanatory message text Where the message text is not self explanatory additional explanation follows
146. d by multiple code streams either multiple processes multiple threads or asynchronous events such as AST routines or condition handlers you need to be aware of certain issues to guarantee correct sharing of data You must inform the compiler that the data being shared may change in an asynchronous fashion By default the compiler assumes that data is only modified by assignment statements routine calls etc If the data is being changed in a way that the compiler does not know about you must use the VOLATILE attribute to tell the compiler that it must fetch the data in an atomic fashion from memory at each reference and the compiler must store the data in an atomic fashion back into memory at each assignment To accomplish atomic access on OpenVMS I64 systems for volatile objects 64 bits or smaller fetches and stores are done with the normal ldn and stn instructions To accomplish atomic access on the Alpha for volatile objects smaller than 32 bits fetches and stores are done with the LDx L STx C instruction sequence This pair of instructions ensures that the volatile data is accessed in an atomic fashion Without the VOLATILE attribute you will not get this special instruction sequence and the data might become corrupted if two writers are trying to store to the shared data at the same time Items of 32 bits or 64 bits are accessed with single longword and quadword instructions and do not use the LDx L STx C sequence Newer Alpha system
147. d format descriptions brackets indicate optional choices You can choose one or more items or no items Do not type the brackets on the command line However you must include the brackets in the syntax for OpenVMS directory specifications and for a substring specification in an assignment statement In command format descriptions vertical bars separate choices within brackets or braces Within brackets the choices are optional within braces at least one choice is required Do not type the vertical bars on the command line In command format descriptions braces indicate required choices you must choose at least one of the items listed Do not type the braces on the command line Bold type represents the introduction of a new term It also represents the name of an argument an attribute or a reason Italic type indicates important information complete titles of manuals or variables Variables include information that varies in system output Internal error number in command lines PRODUCER name and in command parameters in text where dd represents the predefined code for the device type Uppercase type indicates a command the name of a routine the name of a file or the abbreviation for a system privilege A hyphen at the end of a command format description command line or code line indicates that the command or statement continues on the following line All numbers in text are assumed to be decimal unless other
148. d record copies the data into a well aligned record and then writes out the new record A simple conversion program would look like program convert it oldfile newfile align vax enumeration_size byte type oldtype packed record Existing record fields end type newtype record Record fields reorganized for optimal alignment end var oldfile file of oldtype newfile file of newtype oldvar oldtype newvar newtype begin reset oldfile rewrite newfile while not eof oldfile do begin read oldfile oldvar 9 12 Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha For each field sub field etc move the data newvar fieldl oldvar fieldl newvar field2 oldvar field2 write newfile newtype end close oldfile close newfile end Notice the type keyword before the definition of the newtype type Without this keyword newtype would be in the same type definition part as oldtype and would be processed with the same ALIGN and ENUMERATION SIZE settings If you have embedded DOUBLE data you must use the D FLOAT predefined type in the oldtype definition since the default on OpenVMS I64 systems is for T floating format and the default on OpenVMS Alpha systems is for G Floating format The compiler does not allow a simple assignment of a D FLOAT value to a T FLOAT or G FLOAT variable You need to use the CNV CONVERT FLOAT routine pr
149. dE RAE Xa E USE Y GbR ee ER Parameter Passing Descriptions llllsn Parameter Passing Syntax on HP Pascal Parameter Descriptors 0 00 cee cece ee eee Summary of Passing Mechanisms and Passing Semantics HP Pascal Definitions Files 0 0 0 cease Access Type Translations ille Mechanism Type Translations llle Default Values for OpenVMS File Specifications Setting of RMS File Access Block Fields by a Call to the OPEN Procedure i sae e e Rr RE ERE Setting of RMS Record Access Block Fields by a Call to the OPEN Procedure 0 0 0 cece eee ees Setting of Extended Attribute Block Fields by a Call to the OPEN Procedure 0 0 0 cece eee eee eens Setting of Name Block Fields by a Call to the OPEN Procedures uae Gpr op Des WE pa RE MERE CER Unpacked Sizes of Fields and Components STATUS and STATUSV Return Values 4 10 5 16 C 1 Compiler Message Warning Levels Preface This manual describes selected programming tasks using the HP Pascal programming language It contains information on using some HP Pascal language elements in combination and it provides examples of how to improve programming efficiency You can use the information in this manual to write programs or modules for the OpenVMS operating system If you need to write HP Pascal programs or modules that must be compiled by another com
150. default CLASS A descriptor you can specify the DESCR foreign mechanism specifier on the actual VARYING OF CHAR parameter 6 7 Using 64 Bit Pointer Types HP Pascal on OpenVMS I64 and OpenVMS Alpha systems includes limited support for 64 bit pointers 64 bit pointers can be declared by using the QUAD attribute on a pointer variable declaration When QUAD is used the generated code will use all 64 bits of the pointer 6 7 1 Pascal Language Features Not Supported with 64 Bit Pointers Several Pascal features are not supported with 64 bit pointers These features are e Base types of 64 bit pointers cannot contain file types or schema types Programming on OpenVMS Systems 6 17 e The READ built in routine cannot read into variables accessed with 64 bit pointers For example the following code fragment will be rejected by the compiler var quad ptr quad integer begin quad ptr my alloc routine size integer read quad ptr end e Strings allocated in P2 address space cannot be used with the READV or WRITEV predeclared routines e HP Pascal understands 32 bit descriptors as defined by the OpenVMS calling standard Therefore any HP Pascal construct that relies on descriptors is not supported for variables accessed with 64 bit pointers The features rejected for 64 bit pointers are The use of DESCR or STDESCR on actual parameter values accessed with 64 bit pointers For example you cannot do the
151. definition Information This message is issued if you have specified a standard argument other than extended on the compile command line STDSCHEMAUSE Nonstandard use of schema type Information This message is issued if you have specified a standard argument other than extended on the compile command line STDSIMCON Nonstandard only simple constant optional sign or quoted string Information Only simple constants and quoted strings are allowed by the Pascal standard to appear as constants Simple constants are integers character strings real constants symbolic constants constants of type BOOLEAN and enumerated types This message is issued only if you have specified the standard switch on the compile command line STDSPECHAR Nonstandard or in identifier STDSTRCOMPAT Nonstandard string compatibility Information These messages refer to extensions to Pascal and are issued only if you have specified the standard switch on the compile command line Diagnostic Messages C 53 STDSTRUCT Nonstandard types do not have same name Information Because the Pascal standard does not recognize structural compatibility two types must have the same type identifier or type definition to be compatible This message is issued only if you have specified the standard switch on the compile command line STDSYMLABEL Nonstandard symbolic label Information These messages refer to extensions to Pascal and are issued only if y
152. dentifier predeclared by HP Pascal Also HP Pascal allows the following exceptions to the rules concerning multiply declared identifiers e A variable identifier can be multiply declared if all declarations of the variable have the same type and attributes and if all but one declaration at most are external e A procedure identifier can be multiply declared if all declarations of the procedure have congruent parameter lists and if all but one declaration at most are external e A function identifier can be multiply declared if all declarations of the function have congruent parameter lists and identical result types and if all but one declaration at most are external If a compilation unit creates an environment file and if it contains data that you do not want to share with other compilation units you can use the HIDDEN attribute Consider the following example ENVIRONMENT MODULE Example TYPE Array Template Upper INTEGER HIDDEN ARRAY 1 Upper OF INTEGER Global Type Array Template 10 VAR i HIDDEN INTEGER Used for local incrementing PROCEDURE x BEGIN i i 1 END 2 4 Separate Compilation PROCEDURE y BEGIN FOR i i 1 END END The code in the previous example hides the schema type preventing the schema type from being used in inheriting modules Whether to hide the type depends on the requirements of a given application Also HP Pascal does not include the variable i in the
153. des any value you previously specified with this qualifier Table 1 6 lists the available values for keyword Table 1 6 ENUMERATION SIZE Qualifier Options Option Action Default Information BYTE Allocates unpacked enumerated data Default on OpenVMS VAX systems types with up to 255 elements in a single byte Otherwise enumerated data types are allocated in a 16 bit word LONG Allocates all unpacked enumerated Default on OpenVMS I64 and data types in a 32 bit longword OpenVMS Alpha systems NOJENVIRONMENT 1 12 Compiling HP Pascal Programs determined by attributes default Produces an environment file in which declarations and definitions made at the outermost level of a compilation unit are saved The default file name is the same as the source file name The default file type is PEN an abbreviation for Pascal Environment You can provide a different name for the environment file by including a file specification after the ENVIRONMENT qualifier for example ENVIRONMENT MASTER PEN The ENVIRONMENT qualifier on the command line overrides the ENVIRONMENT attribute in the source program or module By default the attributes of the source program or module determine whether an environment file is created however if the ENVIRONMENT qualifier is specified at compile time an environment file will always be created NOJERROR LIMIT ERROR LIMIT 30 default Terminates compilation after the occurrence of a speci
154. different Information This message can appear as additional information on other error messages SIZEINT Size expression must be a positive integer value Error SIZGTRMAX Size exceeds MAXINT bits Error The size of a record or an array type or the size specified by a size attribute exceeds 2 147 483 647 bits The HP Pascal implementation imposes this size restriction Diagnostic Messages C 45 SIZMULTBYT Size of component of array passed by descriptor is not a multiple of bytes Error When an array or a conformant parameter is passed using the DESCR mechanism specifier the descriptor built by the compiler must follow the HP OpenVMS Calling Standard Such a descriptor can describe only an array whose components fall on byte boundaries SPEOVRDECL Foreign mechanism specifier required to override parameter declaration Error When you specify a default value for a formal VAR or routine parameter you must also use a mechanism specifier to override the characteristics of the parameter section SPURIOUS error message at line number column number Information The compiler did not correctly note the location of this error in your program and later could not position and print the correct error message You may be able to correct the section of your program that caused the error and thus avoid this error Please submit a report SPR and provide a machine readable copy of the program if you receive this error
155. ds on component type 3Only if PACKED ARRAY OF CHAR 4Component type can be a conformant VARYING OF CHAR 5 CLASS NCA is used on OpenVMS I64 and OpenVMS Alpha systems CLASS A is used on OpenVMS VAX Systems DTYPE FX is used on OpenVMS I64 and OpenVMS Alpha systems DTYPE H is used on OpenVMS VAX Systems 5 10 Calling Conventions continued on next page Table 5 3 Cont Parameter Descriptors Parameter Type Descriptor Class and Type Value or VAR DESCR STDESCR Semantics Discriminated schema SET DSC K CLASS S DSC K DTYPE Z FILE DSC K CLASS S DSC K DTYPE Z Pointer DSC K CLASS S DSC K DTYPE LU PROCEDURE DSC K CLASS S Bound procedure or DSC K_DTYPE_BPV value by reference FUNCTION CLASS_A CLASS_NCA CLASS_S Ordinal DSC K CLASS S SINGLE DSC K CLASS S DSC K DTYPE F DSC K DTYPE FS DOUBLE DSC K CLASS S DSC K DTYPE D DSC K DTYPE G DSC K DTYPE FT QUADRUPLE DSC K_CLASS_S DSC K DTYPE H Fx RECORD a ARRAY DSC K CLASS A DSC K CLASS DSC K CLASS S NCA DSC K DTYPE T lDescriptor s D type depends on size of type 2Descriptor s D type depends on component type 3Only if PACKED ARRAY OF CHAR DTYPE FX is used on OpenVMS I64 and OpenVMS Alpha systems DTYPE H is used on OpenVMS VAX Systems continued on next page Calling Conventions 5 11 Table 5 3 Cont Parameter Descriptors Parameter Type Descripto
156. dual file operations after the file is opened RAB V RAH Read ahead 1 RAB V TPT Truncate file often PUT May be modified for individual file operations after the file is opened RAB V UIF Update if record exists 1 if ACCESS DIRECT RAB V WBH Write behind 1 RAB W RSZ Record size May be modified for individual file operations after the file is opened RAB L STS Completion status code Returned by RMS RAB L UBF User record area address Set to buffer address after file is opened HP Pascal RTL allocates buffer 1After the call to OPEN this field must contain the same value it had before the call 7 8 Input and Output Processing continued on next page Table 7 3 Cont Setting of RMS Record Access Block Fields by a Call to the OPEN Procedure Field Name OPEN Parameters and Value RAB W USZ User record area size Set to size of record area for files other than TEXT the size is equal to the size of the component type for TEXT files the size is equal to the value of RECORD LENGTH otherwise 255 1After the call to OPEN this field must contain the same value it had before the call Table 7 4 presents the status of RMS XAB fields when you call the OPEN procedure If a field is not included in the following table it is initialized to Zero Table 7 4 Setting of Extended Attribute Block Fields by a Call to the OPEN Procedure Field Name PASCAL OPEN Keyword and Value XAB B DTP Data type of key Set to dat
157. e NO MACHINE CODE NOMACHINE CODE default Produces a machine code section within the listing file If the compiler detects errors in the source code the compiler does not generate this section The compiler ignores this qualifier if you do not also specify LIST on the same command line MATH_LIBRARY keyword OpenVMS Alpha systems only Determines whether the compiler uses alternate math library routines that boost performance but sacrifice accuracy You can specify the following values for keyword e ACCURATE default e FAST Compiling HP Pascal Programs 1 15 NOJOBJECT OBJECTzinput file name OBJ default Specifies the name of the object file If the compiler detects errors in the source code the compiler writes no representation of object code to the listing file NOJOPTIMIZE OPTIMIZE default Directs the compiler to optimize the code for the program or module being compiled so that the compiler generates more efficient code A single identifier or a list of identifiers enclosed in parentheses can follow OPTIMIZE these identifiers are the names of options that tell the compiler which aspects of the compilation unit to optimize Table 1 8 lists the available options their corresponding actions and their negations 1 16 Compiling HP Pascal Programs Table 1 8 OPTIMIZE Qualifier Options Option Action Negation ALL Enables all optimization components NONE INLINE keyword Enables inline expansio
158. e Information The constants MAXCHAR MAXINT64 MAXUNSIGNED MAXUNSIGNED64 MAXREAL MINREAL EPSREAL MAXDOUBLE MINDOUBLE EPSDOUBLE MAXQUADRUPLE MINQUADRUPLE and EPSQUADRUPLE are extensions to Pascal MAXCHAR MAXREAL MINREAL and EPSREAL are contained in Extended Pascal This message is issued only if you have specified the standard switch on the compile command line STDPREDECL Nonstandard predeclared routine Information Many predeclared procedures and functions are extensions to Pascal The use of these routines causes this message to be issued if you have specified the standard switch on the compile command line STDPRESCH Nonstandard predefined schema type name Information This message is issued if you have specified a standard switch other than extended on the compile command line STDPRETYP Nonstandard predefined type type name Information The types SINGLE DOUBLE INTEGER64 QUADRUPLE UNSIGNED UNSIGNED64 and VARYING OF CHAR are extensions to Pascal This message is issued only if you have specified the standard switch on the compile command line STDQUOSTR Nonstandard quotes enclosing radix constant Information This message is issued if you have specified the extended option on the compile command line STDRADFORMAT Nonstandard use format radix nnn for radix constant Information This message refers to the use of an extension to Pascal This message is issued only if you have s
159. e 1 1 lists the values for keyword Table 1 1 ALIGN Qualifier Options Option Action Default Information NATURAL Uses natural alignment when positioning Default on OpenVMS I64 and record fields or array components OpenVMS Alpha systems if ALIGN Natural alignment is when a record is not specified VAX field or an array component is positioned on a boundary based on its size For example 32 bit integers are aligned on the nearest 32 bit boundary Uses byte alignment when positioning Default on OpenVMS VAX systems if record fields or array components ALIGN is not specified Record fields or array components larger than 32 bits are positioned on the nearest byte boundary 1Previous versions of HP Pascal used ALPHA AXP for this keyword The NATURAL keyword is now the recommended spelling for the same behavior The ALPHA AXP keyword will continue to be recognized for compatibility with old command lines On OpenVMS VAX systems when you specify a value of NATURAL automatic variables are aligned on longword boundaries instead of quadword boundaries This occurs because the largest allowable alignment for the stack is longword alignment NOJANALYSIS DATA NOANALYSIS DATA default Creates a file containing source code analysis information If you omit the file specification the analysis file defaults to the name of your source file with a ANA file type The source code analysis file is used with products s
160. e Pascal standard to appear as constants Simple constants are integers character strings real constants symbolic constants and constants of BOOLEAN and enumerated types This message is issued only if you have specified the standard switch on the compile command line STDNOFRML Nonstandard FUNCTION or PROCEDURE parameter declaration lacks formal parameter list Information This message is issued if you try to pass actual parameters to a formal routine parameter for which you declared no formal parameter list You must also have specified the standard switch on the compile command line STDNONPOS Nonstandard nonpositional parameter syntax STDOTHER Nonstandard OTHERWISE clause STDPASSPRE Nonstandard passing predeclared routine name Information These messages refer to extensions to Pascal and are issued only if you have specified the standard switch on the compile command line STDNOTIN Nonstandard NOT IN operator Information This message refers to an extension in Pascal and is issued only if you have specified the standard switch on the compile command line STDPCKSET Nonstandard combination of packed and unpacked sets Information The Pascal standard does not allow packed and unpacked sets to be combined in set operations This message is issued only if you have specified the standard switch on the compile command line Diagnostic Messages C 51 STDPRECONST Nonstandard predeclared constant constant nam
161. e compiler to pass the address of the routine without verifying that the parameter lists are identical e ASTPRM parameter 6 16 Programming on OpenVMS Systems Many system services define this parameter to be an UNSIGNED parameter passed by immediate value Since the parameter to an AST routine is dependent on the application it is often desired to pass the address of a variable instead of its contents To solve this problem you can specify the REF foreign mechanism specifier on the actual parameter This causes the compiler to pass the address of the variable instead of the contents of the variable e P1 Pn parameters The P1 through P6 parameters of the QIO and QIOW system services and the P1 through P20 parameters of the FAO system services are also defined to be UNSIGNED parameters passed by immediate value If the actual parameter is not UNSIGNED or requires a different passing mechanism you can specify the REF foreign mechanism specifier on the actual parameter This causes the compiler to pass the address of the variable instead of the contents of the variable e RESULTANT FILESPEC parameter of the LIB FIND FILE run time library routine This parameter is declared to be a VAR conformant PACKED ARRAY OF CHAR parameter and is passed by a CLASS A descriptor However the LIB FIND FILE routine can also accept CLASS VS descriptors of VARYING OF CHAR variables To cause the compiler to build a CLASS VS descriptor instead of the
162. e data type to be considered for purposes of alignment is not the aggregate itself but rather the elements of which the aggregate is composed Varying 8 bit character strings must for example start at addresses that are a multiple of 2 bytes word alignment because of the 16 bit count at the beginning of the string For records the size is rounded up to a multiple of their natural alignment a record with natural alignment of longword has a size that is a multiple of longwords for example The OpenVMS VAX and naturally aligned record formats are fully documented in the HP OpenVMS Calling Standard The size as well as the alignment of record fields and array components can affect performance On OpenVMS 164 and OpenVMS Alpha systems HP Pascal uses larger allocation for unpacked Booleans and enumeration types to help performance as shown in Table 9 1 Table 9 1 Unpacked Sizes of Fields and Components Datatype Unpacked Size on VAX Unpacked Size on 164 Alpha Boolean 1 byte 4 bytes Enumerated types 1 or 2 bytes 4 bytes 9 4 Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha For compatibility reasons the size of all data types in PACKED records and arrays are the same for both VAX and natural alignment formats 9 7 2 HP Pascal Features Affecting Data Alignment and Size HP Pascal has the following DCL qualifiers e ALIGN keyword where keyword is either NATURAL or VAX e ENUMERATION_SIZE keyword where keyword is eit
163. e du WEE a eX a 1 37 1 4 Error Messages llle 1 38 2 Separate Compilation 2 1 2 2 2 8 2 4 ENVIRONMENT HIDDEN and INHERIT Attributes Interfaces and Implementations l l eee Data Models i jk RR ema ERR EP codices Separate Compilation Examples l l 3 Program Correctness Optimization and Efficiency 3 1 3 1 1 3 1 2 3 1 3 3 1 4 3 1 5 3 1 6 3 1 7 3 1 14 3 1 15 3 1 16 3 1 17 3 1 18 3 1 19 3 2 3 8 3 8 1 3 3 2 3 3 3 3 3 4 3 3 5 3 3 6 Compiler Optimizations 0 0 0 0 ee ees Compile Time Evaluation of Constants Elimination of Common Subexpressions Elimination of Unreachable Code 44 Code Hoisting from Structured Statements Inline Code Expansion for Predeclared Functions Inline Code Expansion for User Declared Routines Testing for Inline Expansion on OpenVMS VAX Systems Operation Rearrangement llle lees Partial Evaluation of Logical Expressions Value Propagation llle ees Strength Reduction OpenVMS I64 and OpenVMS Alpha SyslemiS d irr rr CLr ORE DX upe3 ee sees ts CERA ES Split Lifetime Analysis OpenVMS I64 and OpenVMS Alpha SYSLem8 Ge pudo bed CEU ete hd EegrRORPO d ERR Code Scheduling OpenVMS I64 and OpenVMS Alpha SyStenmis xd ie ense le ese lee us AC e n e C XR a Ce Ras Loop Unrolling OpenVMS I64 and OpenVM
164. e error detection routines in your program Program Correctness Optimization and Efficiency 3 11 3 1 17 Software Pipelining OpenVMS 164 and OpenVMS Alpha systems Software pipelining and additional software dependency analysis are enabled using the OPTIMIZE LEVEL 5 command line option which in certain cases improves run time performance OPTIMIZE LEVEL 5 is not the default OPTIMIZE LEVEL 4 remains the default As compared to regular loop unrolling enabled at optimization level 3 or above software pipelining uses instruction scheduling to eliminate instruction stalls within loops rearranging instructions between different unrolled loop iterations to improve performance For instance if software dependency anaylsis of data flow reveals that certain calculations can be done before or after that iteration of the unrolled loop software pipelining reschedules those instructions ahead or behind that loop iteration at places where their execution can prevent instruction stalls or otherwise improve performance For this version of HP Pascal loops chosen for software pipelining e Are always innermost loops those executed the most e Do not contain branches or procedure calls By modifying the unrolled loop and inserting instructions as needed before and or after the unrolled loop software pipelining generally improves run time performance except for cases where the loops contain a large number of instructions with many existing
165. e field width or radix expression in a WRITE WRITELN or WRITEV routine must be of type INTEGER FORACTORD FOR loop control variable must be of an ordinal type FORACTVAR FOR loop control must be a true variable Error The control variable of a FOR statement must be a simple variable of an ordinal type and must be declared in a VAR section For example it cannot be a field in a record that was specified by a WITH statement or a function identifier FLDWDTHINT Field width expression must be of type integer Error FORCTLVAR variable name is a FOR control variable Warning The control variable of a FOR statement cannot be assigned a value used as a parameter to the ADDRESS function passed as a writable VAR REF DESCR or STDESCR parameter used as the control variable of a nested FOR statement or written into by a READ READLN or READV procedure FORINEXPR Expression is incompatible with FOR loop control variable Error The type of the initial or final value specified in a FOR statement is variable C 20 Diagnostic Messages FRMLPRMDESC Formal parameters use different descriptor formats FRMLPRMINCMP Formal routine parameters are not compatible FRMLPRMNAM Formal parameters have different names FRMLPRMSIZ Formal parameters have different size attributes FRMLPRMTYP Formal parameters have different types Information These messages can appear as additional information on other error messages FRSTPRMSTR READV r
166. e only provided on OpenVMS 164 and OpenVMS Alpha systems 6 2 Programming on OpenVMS Systems continued on next page Table 6 1 Cont HP Pascal Definitions Files File Description Run Time Library Definitions Files PASCAL OTS ROUTINES PAS PEN PASCAL PPL ROUTINES PAS PEN PASCAL PSM ROUTINES PAS PEN PASCAL SMB ROUTINES PAS PEN PASCAL SMG ROUTINES PAS PEN PASCAL SOR_ROUTINES PAS PEN PASCAL STR_ROUTINES PAS PEN PASCAL TPU_ROUTINES PAS PEN Contains OTS routine entry points Contains PPL routine entry points data structures and messages Contains PSM routine entry points Contains SMB routine entry points Contain SMG routine entry points and messages Contains SOR routine entry points and messages Contains STR routine entry points Contains TPU routine entry points Symbol Definitions Files LIBDEF PAS MTHDEF PAS SIGDEF PAS Contains definitions for all condition symbols from the general utility run time library routines Contains definitions for all condition symbols from the mathematical routines library Contains miscellaneous symbol definitions used in condition handlers These definitions are also included in STARLET PEN HP Pascal Run Time Library Files PASDEF PAS Contains definitions for all condition symbols from the HP Pascal run time library routines 1These files are retained for compatibility with older versions of this
167. e syntax used to define a dynamic array parameter has been decommitted for the current version of HP Pascal You should edit your program to make the type definition conform to the current version conformant array syntax VI1DYNARRASN Decommitted Version 1 dynamic array assignment Error In VAX Pascal Version 1 0 dynamic arrays used in assignments could not be checked for compatibility until run time This warning indicates that your program depends on an obsolete feature which you should consider changing to reflect the current version syntax for conformant array parameters V1MISSPARM Decommitted missing parameter syntax correct by adding number of commas comma s Error An OPEN procedure called with the decommitted VAX Pascal Version 1 0 syntax fails to mark omitted parameters with commas Your program depends on this obsolete feature and you should insert the correct number of commas as listed in the message Diagnostic Messages V1PARMSYN Use of unsupported V1 omitted parameter syntax with new V2 feature s Error In a parameter list for the OPEN procedure you cannot use both the Version 1 0 syntax for OPEN and the parameters that are new to subsequent versions of HP Pascal V1RADIX Decommitted Version 1 radix output specification Error In VAX Pascal Version 1 0 octal and hexadecimal values could be written by placing the keywords OCT or HEX after a field width expression Your program uses this obsolete feature yo
168. e used in the second user action function User Open is then assigned the value of Status in this case TRUE which is returned to the main program The function User Create is called as a result of the OPEN procedure for the output file F Out The function assigns the allocation quantity of the input file to the FAB FAB L ALQ field of the FAB which contains the allocation size for the output file The FAB field FAB FAB V_CBT is set to FALSE to disable the request that file storage be allocated contiguously on a best try basis Then the FAB field FAB FAB V_CTG is set to TRUE so that contiguous storage allocation is mandatory Finally the RMS service CREATE is performed If CREATE is successful CONNECT will be done and the function return value will be that of CREATE Once the OPEN procedures have been performed successfully the program can then accomplish its main task copying the input file F In to the output file F Out which is the same size as F_In and has contiguous allocation The last step in the program is to close the files Input and Output Processing 7 13 For More Information e On the OPEN and CLOSE procedures HP Pascal for OpenVMS Language Reference Manual e On RMS file access blocks Section 7 1 6 2 7 3 File Sharing Through the RMS file sharing capability a file can be accessed by more than one executingprogram at a time or by the same program through more than one file variable There are two kinds of f
169. eate the file with relative or indexed organization If you are using direct access on a sequential file individual records can be updated with the LOCATE and PUT procedures See Chapter 7 to determine whether a different file organization may be appropriate for your application VARINDVAL VARYING index value exceeds current length Explanation The index value specified for VARYING OF CHAR string is greater than the string s current length User Action Correct the index value so that it specifies a legal character in the string WIDTOOLRG totalwidth too large Explanation The requested total width for the floating point write operation overflowed an internal buffer User Action Examine the source program to see if the specified total width parameter is correct If it is correct please submit a problem report including a machine readable copy of your program data and a sample execution illustrating the problem WRIINVENU WRITE of an invalid enumerated value Explanation Your program attempted to write an enumerated value using a WRITE or WRITEV procedure but the internal representation of that value was outside the possible range for the enumerated type User Action Verify that your program is not improperly using PRED SUCC or type casting to assign an invalid value to a variable of enumerated type C 86 Diagnostic Messages A Access method type translations 6 7 ACCURACY SENSITIVE 1 7 Action routine using t
170. ecifier has no effect over the generated code since the function descriptors in the OpenVMS Calling Standard allow any combination of bound and unbound routines to be passed around and invoked On OpenVMS 164 systems HP Pascal expects the address of a function descriptor for routine parameters In all OpenVMS I64 languages asking for the address of a routine yields the address of its function descriptor since the actual address of the instructions is not useful by itself On OpenVMS Alpha Systems By default HP Pascal on OpenVMS Alpha systems passes the address of a procedure descriptor for PROCEDURE or FUNCTION parameters The presence of the UNBOUND attribute or the IMMED foreign mechanism specifier has no effect over the generated code since the procedure descriptors in the OpenVMS Calling Standard allow any combination of bound and unbound routines to be passed around and invoked On OpenVMS Alpha systems HP Pascal expects the address of a procedure descriptor for routine parameters In all OpenVMS Alpha languages asking for the address of a routine yields the address of its procedure descriptor since the actual address of the instructions is not useful by itself On OpenVMS VAX Systems By default HP Pascal on OpenVMS VAX will pass the address of a BPV Bound Procedure Value for PROCEDURE or FUNCTION parameters The BPV is a 2 longword structure with the 1st longword being the address of the entry mask of the routine being pa
171. eclaration part has been completely processed INSNOTALL Inspection mode is not allowed for a WRITEONLY file Explanation Your program attempted to place a file declared with the WRITEONLY attribute into inspection mode which is not allowed User Action Correct the program so that the file variable either does not have the WRITEONLY attribute or is not placed into inspection mode INSVIRMEM insufficient virtual memory Explanation The run time library was unable to allocate enough heap storage to open the file User Action Examine your program to see whether it is making excessive use of heap storage which might be allocated using the NEW procedure or the run time library procedure LIB GET_VM Modify your program to free any heap storage it does not need Diagnostic Messages C 75 INVARGPAS invalid argument to Pascal Run Time Library Explanation An invalid argument or inconsistent data structure was passed to the run time library by the compiled code or a system service returned an unrecognized value to the run time library User Action Rerun your program with all CHECK options enabled Make sure that the version of the current operating system is compatible with the version of the compiler If you cannot locate an error in your program and the problem persists please submit a Software Performance Report SPR to Hewlett Packard and include a machine readable copy of your program data and results of a sample execution showin
172. ed TAGNOTORD Tag type must be an ordinal type Error The type of a variant record s tag field must be one of the ordinal types C 58 Diagnostic Messages TOOIDXEXPR Too many index expressions type has only number of dimensions dimensions Error A call to the UPPER or LOWER function specified an index value that exceeds the number of dimensions in the dynamic array TOOMANYIFS Conditional compilation nesting level exceeds implementation limit Error IF directives may only be nested 32 deep TOPROGRAM TO BEGIN END DO not allowed in PROGRAM Error TO BEGIN DO and TO END DO declarations are only allowed in modules TYPCNTDISCR Type can not be discriminated in this context Error TYPFILSIZ Type contains one or more FILE components size attribute is illegal Error The allocation size of a FILE type cannot be controlled by a size attribute therefore you cannot use a size attribute on any type that has a file component TYPHASFILE Type contains one or more FILE components Error Many operations are illegal on objects of type FILE and objects of structured types with file components for example you cannot initialize them use them as value parameters or read them with input procedures TYPHASNOVRNT Type contains no variant part Error You can only use the formats of the NEW DISPOSE and SIZE routines that allow case labels to be specified when their parameters have variants TYPPTRFIL Type must be point
173. ed routine The type of the CLASS A and CLASS NCA parameter must be an array packed or unpacked fixed or conformant of an ordinal or real type With the CLASS A and CLASS NCA attributes the type of passing semantics used for the by descriptor argument depends on the use of the VAR keyword If the formal parameter name is preceded by the reserved word VAR variable semantics is used otherwise value semantics is used 5 3 3 3 STDESCR Mechanism Specifier When you use the STDESCR mechanism specifier the compiler generates a fixed length descriptor of a character string variable and passes its address to the called routine Only items of the following types can have the STDESCR specifier on the actual parameter character string constants string expressions packed character arrays with lower bounds of 1 and packed conformant arrays with indexes of an integer or integer subrange type The passing semantics depend on the variable represented by the actual parameter as follows e Ifthe actual parameter is a variable of type PACKED ARRAY OF CHAR STDESCR implies variable semantics within the called routine e Ifthe actual parameter is either a variable enclosed in parentheses an expression or a VARYING OF CHAR variable STDESCR implies foreign semantics If the actual parameter is not modified by the called external routine the corresponding formal parameter should be declared READONLY saving the copy from having to be made
174. ed when the file was created User Action If the program needs to detect this situation when it occurs specify the ERROR CONTINUE parameter for the UPDATE procedure and use the STATUS function to determine which error if any occurred If necessary modify the program so that it does not improperly change a key field or recreate the file specifying that the key field is permitted to change See Chapter 7 for more information Diagnostic Messages C 79 KEYDEFINC KEY nnn definition is inconsistent with this file Explanation An indexed file of type RECORD was opened and the component type contained fields whose KEY attributes did not match those of the existing file The number of the key in error is displayed in the message User Action Correct the RECORD definition so that it describes the correct KEY fields or recreate the file so that it matches the declared keys See Chapter 7 for more information KEYDUPNOT key field duplication is not allowed Explanation Your program attempted an UPDATE or PUT procedure for a record of an indexed file that would have duplicated a key field value of an existing record and this situation was disallowed when the file was created User Action If the program needs to detect this situation when it occurs specify the ERROR CONTINUE parameter for the PUT or UPDATE procedure and use the STATUS function to determine which error if any occurred If necessary modify the program so that it doe
175. ed with a default you must pass an actual parameter to it when calling its routine PARMCLAMAT Parameter section classes do not match Information This message can appear as additional information on other error messages PARMLIMIT OpenVMS architectural limit of 255 parameters exceeded Error You cannot declare a procedure with more than 255 formal parameters A function whose result type requires that the result be stored in more than 64 bits or whose result type is a character string cannot have more than 254 formal parameters In a call to a routine declared with the LIST attribute you also cannot pass more than 255 or 254 actual parameters PARMSECTMAT Division into parameter sections does not match Information This message can appear as additional information on other error messages PARSEFAIL error parsing command line use PASCAL command Fatal The HP Pascal compiler was invoked without using the PASCAL DCL command PARSEFAIL error parsing command line using an invalid CLD table Fatal The HP Pascal compiler was invoked with an incorrect or obsolete command line definition in SYS LIBRARY DCLTABLES Contact your system manager to reinstall SYS LIBRARY DCLTABLES C 38 Diagnostic Messages PASPREILL Passing predeclared routine name is illegal Error You cannot use the IADDRESS function on a predeclared routine for which there is no corresponding routine in the run time library such as the interlocked functio
176. edure or function heading is not one of those recognized by the HP Pascal compiler IVENVIRON Environment environment name has illegal format source analysis terminated Fatal The environment file inherited by the program has an illegal format compilation is immediately aborted However a listing will still be produced if one was being generated IVFUNC Invalid use of function function name IVFUNCALL Invalid use of function call IVFUNCID Invalid use of function identifier Error These messages result from illegal attempts to assign values or otherwise refer to the components of the function result if its type is structured use the type cast operator on a function identifier or its result or deallocate the storage reserved for the function result if its type is a pointer IVKEYOPT Unrecognized KEY option Error IVKEYVAL FINDK KEY_VALUE cannot be an array other than PACKED ARRAY 1 n OF CHAR Error IVKEYWORD Missing or unrecognized keyword Error The compiler failed to find an identifier where it expected one in a call to the OPEN or CLOSE procedure or it found an identifier that was not legal in this position in the parameter list IVMATCHTYP Invalid MATCH_TYPE parameter to FINDK Error IVOPTMOPT Unrecognized OPTIMIZE option Warning C 26 Diagnostic Messages IVOTHVRNT Illegal use of OTHERWISE within CASE variant Error The HP Pascal extension of using OTHERWISE in a record cons
177. eful without the associated procedure descriptor 9 6 Different Descriptor Classes for Conformant Array Parameters HP Pascal uses the by descriptor mechanism to pass conformant parameters from one routine to another For conformant array parameters HP Pascal uses a CLASS A descriptor on OpenVMS VAX systems and a CLASS NCA descriptor on OpenVMS I64 and OpenVMS Alpha systems The CLASS NCA descriptors generate more efficient code when accessing array components and are able to describe arrays with alignment holes or padding more common on Itanium and Alpha systems If you have a foreign routine that constructs CLASS A descriptors for Pascal you need to examine the code to see if changes are necessary e For certain actual parameters the CLASS A and CLASS NCA descriptors are identical except for the DSC B CLASS field which HP Pascal does not examine e For other parameters you will either have to generate a CLASS NCA descriptor or you can add an explicit CLASS A attribute to the formal conformant parameter in the Pascal routine 9 7 Data Layout and Conversion On OpenVMS 164 and OpenVMS Alpha systems and to a lesser extent OpenVMS VAX systems the layout of data can severely impact performance The Itanium and Alpha architecture and the OpenVMS I64 and OpenVMS Alpha systems have strong preferences about data alignment and size The HP Pascal compiler has several features to enable you to write Pascal code that will get the be
178. egers or unsigned integers all set elements in the set s type definition or in a constructor for the set must be in the range 0 255 C 44 Diagnostic Messages SIZACTDIFF SIZE of actual differs from that of other parameters in same section Error All actual parameters passed to a formal parameter section whose type is a conformant schema must have identical bounds and be structurally compatible This message refers to the allocation size of the array s outermost dimension SIZARRNCA Explicit size on ARRAY dimension makes CLASS NCA mandatory Error SIZATRTYPCON Size attribute type conflict Error For an ordinal type the size specified must be at least as large as the packed size but no larger than 32 bits on OpenVMS VAX or 64 bits on OpenVMS Alpha and OpenVMS 164 systems Pointer types may be either 32 or 64 bits on OpenVMS 164 and OpenVMS Alpha systems Pointers types must be 32 bits on OpenVMS VAX systems Type SINGLE exactly 32 bits type DOUBLE exactly 64 bits and type QUADRUPLE exactly 128 bits For types ARRAY RECORD SET and VARYING OF CHAR the size specified must be at least as large as their packed sizes For the details of allocation sizes in HP Pascal see the HP Pascal for OpenVMS Language Reference Manual SIZCASTYP Variable s size conflicts with cast s target type Error In a type cast operation the size of the variable and the size of the type to which it is cast must be identical SIZEDIFF Sizes are
179. en the file using a RESET REWRITE or OPEN procedure as appropriate See Chapter 7 for more information Diagnostic Messages C 73 FILNOTSEQ file is not sequential organization Explanation Your program attempted to execute the TRUNCATE procedure on a file that does not have sequential organization TRUNCATE is valid only on sequential files User Action Make sure that your program is accessing the correct file Correct the program so that all TRUNCATE operations are performed on sequential files FILNOTTEX file is not a textfile Explanation Your program performed a file operation that required a file of type TEXT on a nontext file Note that the type FILE OF CHAR is not equivalent to TEXT unless you have compiled the program with the OLD VERSION qualifier User Action Make sure that your program is accessing the correct file Correct the program so that a text file is always used when required GENNOTALL Generation mode is not allowed for a READONLY file Explanation Your program attempted to place a file declared with the READONLY attribute into generation mode which is not allowed Note that the READONLY file attribute is not equivalent to the HISTORY READONLY parameter to the OPEN procedure User Action Correct the program so that the file either does not have the READONLY attribute or is not placed into generation mode GETAFTEOF GET attempted after end of file Explanation Your program attempted a GET operati
180. eneric and Host OpenVMS Alpha systems only Compiling HP Pascal Programs 1 17 The OPTIMIZE qualifier without options is equivalent to OPTIMIZE ALL The negation NOOPTIMIZE is equivalent to OPTIMIZE NONE The OPTIMIZE and NOOPTIMIZE attributes in the source program or module override the OPTIMIZE and NOOPTIMIZE qualifiers on the command line For More Information e On compiler optimizations Section 3 1 The NOOPTIMIZE qualifier guarantees full evaluation of both operands of the AND and OR Boolean operators to aid in diagnosing all potential programming errors If you wish to have short circuit evaluation even with the NOOPTIMIZE qualifier use the AND THEN and OR ELSE Boolean operators On OpenVMS I64 and OpenVMS Alpha systems you can also specify an optimization level Optimization levels from level 2 and higher include all optimizations from lower levels NOJPLATFORMS NOPLATFORMS default Displays informational messages about nonportable language features for the specified platform Table 1 9 lists the supported platforms Table 1 9 PLATFORMS Qualifier Options Option Action COMMON Displays informational messages for all platforms OpenVMS I64 Displays informational messages for the OpenVMS I64 platform OpenVMS Alpha Displays informational messages for the OpenVMS Alpha platform OpenVMS VAX Displays informational messages for the OpenVMS VAX platform PSECT MODEL NO MULTILANGUAGE OpenVMS A
181. environment file this allows inheriting modules to declare the identifier variable i as an incrementing variable without being concerned about generating errors for a multiply defined identifier HP Pascal performs compile time and link time checks to ensure that all compilations that inherit environment files actually used the same environment file definition Information is placed in the object file such that the OpenVMS Linker performs the same check between each object file that inherited environment files By default compilation units that inherit an environment file compare the embedded compilation time inside the environment file e Uses found in any other environment files that are also inherited If the times are different a compile time message is displayed This checking can be disabled or modified by using the PEN CHECKING STYLE attribute in the Pascal source file that created the environment file Once the environment file exists its selected checking style will be performed at each use The PEN CHECKING STYLE attribute is valid at the beginning of a MODULE that creates an environment The syntax is PEN CHECKING STYLE keyword In this format keyword is e COMPILATION TIME Uses the compilation time of the environment file in all subsequent compile time checking for users of this environment file This is the default DENT STRING Uses the IDENTY string of the environment file in all subsequent compi
182. equires first parameter to be a string expression Error You must specify at least two parameters for the READV procedure a character string expression and a variable into which new values will be read FRSTPRMVARY WRITEV requires first parameter to be a variable of type VARYING Error FTRNOTHER Feature not supported io this context Error FTRNOTPOR Feature not supported on platform s Information FTRNOTSUP Feature not supported on this platform Error FUNCTRESTYP Routine must be declared as FUNCTION to specify a result type Error You cannot specify a result type on a PROCEDURE declaration FUNRESTYP Function result types are different Information This message can appear as additional information on other error messages Diagnostic Messages C 21 FWDREPATRLST Declared FORWARD repetition of attribute list not allowed FWDREPPRMLST Declared FORWARD repetition of formal parameter list not allowed FWDREPRESTYP Declared FORWARD repetition of result type not allowed Error If the heading of a routine has the FORWARD directive the declaration of the routine body cannot repeat the formal parameter list the result type applies only if the routine is a function or any attribute lists that appeared in the heading FWDWASFUNC FORWARD declaration was FUNCTION FWDWASPROC FORWARD declaration was PROCEDURE Error GOTONOTALL GOTO not allowed to jump into a structured statement Warning Jumping into a
183. er or FILE Error You cannot use the syntax Variable to refer to an object whose type is not pointer or FILE TYPREF REF not allowed for this type Error The REF foreign mechanism specifier cannot be used with schematic variables Diagnostic Messages C 59 TYPSTDESCR STDESCR not allowed for this type Error The 2STDESCR mechanism specifier is allowed only on objects of type CHAR PACKED ARRAY 1 n OF CHAR VARYING OF CHAR and arrays of these types TYPVARYCHR Component type of VARYING must be CHAR Error UNALIGNED variable name is UNALIGNED Error or Warning You cannot use the data items listed in a call to the ADDRESS function nor can you pass them as writable VAR 6REF DESCR or STDESCR parameters This message is at warning level if the variable or component has the UNALIGNED attribute and at error level if the variable or component is actually unaligned UNAVOLACC Volatile access appears unaligned but must be aligned at run time to ensure atomicity and byte granularity Warning The code generator was unable to determine if a volatile access was aligned or not It generated two sequences one sequence will perform the atomic access if it was aligned properly the second sequence accesses the object but may contain a timing window where incorrect results may occur UNBPNTRET routine name is not UNBOUND frame pointer not returned Warning The IADDRESS function returns only the address of
184. ery end of the record since their offset requires run time computation You can get the optimal record layout by e Avoiding the PACKED keyword except for PACKED ARRAY OF CHARs and possibly PACKED SETs e Avoiding explicit POS or ALIGNED attributes e Placing larger fields before smaller fields e Placing fixed size fields before run time sized fields 9 7 4 Optimal Data Size Data items that are smaller than 32 bits might impose a performance penalty due to the additional instructions required to access them The compiler will attempt to reorder loads and stores that manipulate adjacent items smaller than 32 bits to minimize the number of memory references required For performance reasons HP Pascal on OpenVMS I64 and OpenVMS Alpha systems will allocate Boolean and enumerated types as longwords in unpacked records or arrays On OpenVMS VAX systems you have to explicitly request this with a DCL qualifier or the corresponding attribute You should avoid any explicit size attributes on subrange types While it is true that BYTE 0 255 is smaller than 0 255 which would allocate 4 bytes since it is a subrange of INTEGER the additional overhead of accessing the byte sized subrange might be than the extra 3 bytes of storage Using the BIT attribute on subranges is even less effective in terms of the extra instructions required to manipulate a 13 bit integer subrange inside a record Use these attributes only where needed Migrating fr
185. es a substring that can be extracted from the original string See the HP Pascal for OpenVMS Language Reference Manual for complete information on the SUBSTR function TEXREQSEQ textfiles require sequential organization and access Explanation Your program attempted to open a file of type TEXT that either did not have sequential organization or had an ACCESS METHOD other than SEQUENTIAL the default when opened by the OPEN procedure User Action Make sure that the program refers to the correct file Correct the program so that only sequential organization and access are used for text files Diagnostic Messages C 85 TRUNOTALL TRUNCATE is not allowed for a shared file Explanation Your program attempted to call the TRUNCATE procedure for a file that was opened for shared access You cannot truncate files that might be shared by other users This message may also be issued if you do not have permission to write to the file User Action Correct the program so that it does not try to truncate shared files If the file is opened with the OPEN procedure do not specify a value other than NONE the default for the SHARING parameter UPDNOTALL UPDATE not allowed for a sequential organization file Explanation Your program attempted to call the UPDATE procedure for a sequential file UPDATE is valid only on relative and indexed files User Action Correct the program so that it does not try to use UPDATE for sequential files or recr
186. ess violations UNREAD Variable variable name is assigned into but never read Information UNSCNFVRY UNSAFE attribute not allowed on conformant VARYING parameter Error UNSEXCRNG constant exceeds range of datatype Error The largest value allowed for an UNSIGNED value is 4 294 967 295 The largest value allowed for an UNSIGNED64 value is 18 446 744 073 709 551 615 UNUSED Variable variable name is never referenced Information UNWRITTEN Variable variable name is read but never assigned into Warning Diagnostic Messages C 61 C 62 UPLEVELACC Unbound routine name precludes uplevel access to variable name Error A routine that was declared with the UNBOUND attribute cannot refer to automatic variables routines or labels declared in outer blocks UPLEVELGOTO Unbound routine name precludes uplevel GOTO to label name Error A routine that was declared with the UNBOUND attribute cannot refer to automatic variables routines or labels declared in outer blocks USEDBFDECL symbol name was used before being declared Warning USEINISTA Use initial state VALUE clause on TYPE or VAR declaration Information Nonstatic variables such as those created from schema types cannot be initialized in the VALUE declaration part To initialize these variables you must use the initial state feature VIDYNARR Decommitted Version 1 dynamic array type Error The typ
187. essage may be generated In most cases you should be able to understand the error by looking up the first message in the following list If not see the OpenVMS System Messages and Recovery Procedures Reference Manual for an explanation of the RMS error message All diagnostic messages contain a brief explanation of the event that caused the error This section lists run time diagnostic messages in alphabetical order including explanatory message text Where the message text is not self explanatory additional explanation follows Portions of the message text enclosed in quotation marks are items that the compiler substitutes with the name of a data object when it generates the message Diagnostic Messages C 65 ACCMETINC ACCESS METHOD specified is incompatible with this file Explanation The value of the ACCESS METHOD parameter for a call to the OPEN procedure is not compatible with the file s organization or record type You can use DIRECT access only with files that have relative organization or sequential organization and fixed length records You can use KEYED access only with indexed files User Action Make sure that you are accessing the correct file See Chapter 7 to determine which access method you should use AMBVALENU string is an ambiguous value for enumerated type type Explanation While a value of an enumerated type was being read from a text file not enough characters of the identifier were found to specify a
188. etime analysis 3 9 SS CONTINUE return value returned by condition handler 8 7 SS RESIGNAL return value returned by condition handler 8 7 Stack frame definition of 8 2 Index 10 STANDARD qualifier 1 20 STARLET file contents of 6 1 STATUS function conditions detected by A 1 to A 4 STATUSV function conditions detected by A 1 to A 4 STDESCR mechanism specifier 5 13 Strength reduction 3 9 STRING type as function result type 5 3 Structured statement effect on efficiency 3 14 optimization of 3 5 Structure layout 1 28 Subexpression optimization of 3 4 Subrange run time checking of 1 7 Symbol table in object module library 1 36 SYNCHRONOUS EXCEPTIONS qualifier 1 21 SYS FAO routine P1 P20 parameters 6 17 SYS LP LINES logical name 1 26 SYS QIO routine P1 P6 parameters 6 17 SYS QIOW routine P1 P6 parameters 6 17 System routines 6 1 to 6 13 calling of 6 13 data structure parameter 6 9 declaring 6 5 definition file for 6 1 optional parameters for 6 11 System services 6 13 T Table of contents in listing file 1 27 Temporary variable effect on efficiency 3 15 TERMINAL qualifier 1 21 Text library defining a default 1 31 specifying with INCLUDE directive 1 29 specifying with PASCAL command 1 30 TIE qualifier 1 21 TO BEGIN DO section 2 12 2 15 Tokens use with LSE 4 3 TRACEBACK qualifier with LINK command 1 35 Trap conditi
189. evaluate and deposit into variables record fields and array components An exception to this occurs under the following circumstances if a variable is not referenced in a program the HP Pascal compiler may not allocate the variable If the variable is not allocated and you try to examine it or deposit into it you will receive an error message When depositing data into variables the debugger truncates the high order bits if the value being deposited is larger than the variable it fills the high order bits with zeros if the value being deposited is smaller than the variable If the deposit violates the rules of assignment compatibility the debugger displays an informational message Programming Tools 4 1 Automatic variables within any active block can be examined and can have values deposited into them however since automatic variables are allocated in stack storage and are contained in registers their values are considered undefined until the variables are initialized or assigned a value For example DBG EXAMINE X MAINP X 2147287308 In this example the value of variable X should be considered undefined until after a value has been assigned to X In addition you may examine a VARYING OF CHAR string but it is not possible to examine the LENGTH field For example the following is not supported DBG EXAMINE VARY STRING LENGTH Because the current LENGTH of a VARYING string is the first word you should do the followi
190. execute faster and more efficiently than a nonoptimized program The language elements you use in the source program directly affect the compiler s ability to optimize the object program Therefore you should be aware of the ways in which you can assist compiler optimization In addition this awareness often makes it easier for you to track down the source of a problem when your program exhibits unexpected behavior Program Correctness Optimization and Efficiency 3 1 The compiler performs the following optimizations Compile time evaluation of constant expressions Elimination of some common subexpressions Partial elimination of unreachable code Code hoisting from structured statements including the removal of invariant computations from loops Inline code expansion for many predeclared functions Inline code expansion for user declared routines Rearrangement of unary minus and NOT operations to eliminate unary negation and complement operations Partial evaluation of logical expressions Propagation of compile time known values Strength reduction OpenVMS I64 and OpenVMS Alpha systems Split lifetime analysis OpenVMS I64 and OpenVMS Alpha systems Code scheduling OpenVMS I64 and OpenVMS Alpha systems Loop unrolling OpenVMS I64 and OpenVMS Alpha systems Software pipelining OpenVMS 164 and OpenVMS Alpha systems These optimizations are described in the following sections In addition the compiler performs the following opt
191. expression expected SYNEXSEOTEN Syntax expression OTHERWISE or END expected SYNFUNPRO Syntax FUNCTION or PROCEDURE expected SYNHEADTYP Syntax routine heading or type identifier expected SYNIDCAEND Syntax identifier CASE or END expected SYNIDCARP Syntax identifier CASE or expected SYNIDCASE Syntax identifier or CASE expected SYNIDENT Syntax identifier expected SYNILLEXPR Syntax ill formed expression SYNINT Syntax integer expected SYNINTBOO Syntax integer boolean or string literal expected SYNINVSEP Syntax invalid token separator SYNIVATRLST Syntax illegal attribute list SYNIVPARM Syntax illegal actual parameter SYNIVPRMLST Syntax illegal actual parameter list SYNIVSYM Syntax illegal symbol SYNIVVAR Syntax illegal variable SYNLABEL Syntax label expected SYNLBRAC Syntax expected SYNLPAREN Syntax expected SYNLPASEM Syntax or 5 expected SYNLPCORB Syntax C 5 or P expected SYNLPSECO Syntax 5 or expected SYNMECHEXPR Syntax mechanism specifier or expression expected SYNNEWSTMT Syntax start of new statement expected SYNOF Syntax OF expected SYNPARMLST Syntax actual parameter list Diagnostic Messages C 57 SYNPARMSEC Syntax parameter section expected SYNPERIOD Syntax expected SYNPROMOD Syntax PROGRAM or MODULE expected SYNQUOSTR Syntax quoted string expected SYNRBRAC Syntax expected
192. fied by a KEY attribute must fall in the integer subrange 0 254 KEYNOTALIGN KEY key number field field name at bit position bit position is unaligned KEYORDSTR KEY allowed only on ordinal and fixed length string fields KEYPCKREC KEY field in PACKED RECORD must have an alignment attribute KEYREDECL Key number key number is multiply defined KEYSIZ1_2_4 Size of an ordinal key must be 1 2 or 4 bytes KEYSIZ2_4 Size of a signed integer key must be 2 or 4 bytes KEYSIZSTR Size of a string key cannot exceed 255 bytes KEYUNALIGN KEY field cannot be UNALIGNED Error C 28 Diagnostic Messages LABDECIMAL Label number must be expressed in decimal radix Error LABINCTAG Variant case label s type is incompatible with tag type Error The type of a constant specified as a case label of a variant record is not assignment compatible with the type of the tag field LABNOTEND No definition of label label name in statement part of block name Error A label that you declared in a LABEL section does not prefix a statement in the executable section LABREDECL Redefinition of label label name in block name Error A label cannot prefix more than one statement in the same block LABRNGTAG Variant case label does not fall within range of tag type Error A constant specified as a case label of a variant record is not within the range defined for the type of the tag field LABTOOBIG Label label
193. fied number of error messages excluding warning level and information level errors If you specify NOERROR LIMIT compilation continues until 500 errors have been detected FLOAT floattype Selects the default format for REAL and DOUBLE data types You must specify floattype if you use the FLOAT qualifier Table 1 7 lists the available options their corresponding actions and default information If the source program includes the NO G FLOATING attribute then the value of the FLOAT qualifier must be in agreement with the value of the attribute Table 1 7 FLOAT Qualifier Options Option Action Default Information D FLOAT REAL data type will be defined Default for OpenVMS VAX systems if in the F floating point format FLOAT or DOUBLE will be defined in the NOG FLOATING is not specified D floating point format G FLOAT REAL data type will be defined Default for OpenVMS Alpha systems if in the F floating point format FLOAT or DOUBLE will be defined in the NOG FLOATING is not specified G floating point format IEEE FLOAT REAL data type is defined in the Default for OpenVMS I64 systems if IEEE S floating point format FLOAT or DOUBLE is defined in the IEEE NOG FLOATING is not specified T floating point format Compiling HP Pascal Programs 1 13 Routines and compilation units between which double precision quantities are passed should not mix floating point formats On OpenVMS I64 systems VAX floating po
194. files HP OpenVMS Linker Utility Manual Compiling HP Pascal Programs 1 35 1 2 3 Object Module Libraries An object module library contains modules of program text that have been successfully compiled To link modules contained in a object module library use the INCLUDE qualifier and specify the modules you want to link For example LINK GARDEN VEGETABLES INCLUDE EGGPLANT TOMATO BROCCOLI ONION This example directs the linker to link the subprogram modules EGGPLANT TOMATO BROCCOLI and ONION with the main program module GARDEN Besides program modules an object module library can also contain a symbol table with the names of each global symbol in the library and the name of the module in which they are defined You specify the name of the object module library containing symbol definitions with the LIBRARY qualifier When you use the LIBRARY qualifier during a link operation the linker searches the specified library for all unresolved references found in the included modules during compilation Also by default the linker automatically searches the system supplied shareable image library SYS LIBRARY IMAGELIB OLB after searching any libraries you specify on the LINK command In the following example the linker uses the library RACQUETS to resolve undefined symbols in BADMINTON TENNIS and RACQUETBALL LINK BADMINTON TENNIS RACQUETBALL RACQUETS LIBRARY You can define an object module library to be your defau
195. flex Consider the following example VAR X INTEGER p INTEGER In the executable section NER p 1 1 gt i l X 0 0 IFp x THEN p p 1 If a pointer variable in your program must refer to a variable with an explicit name that variable must be declared VOLATILE or READONLY The compiler makes no assumptions about the value of volatile variables and therefore performs no optimizations on them Use of the ADDRESS function which creates a pointer to a variable can result in a warning message because of optimization characteristics By passing a nonread only or nonvolatile static or automatic variable as the parameter to the ADDRESS function you indicate to the compiler that the variable was not allocated by NEW but was declared with its own identifier Because the compiler s assumptions are incorrect a warning message occurs You can also use IADDRESS which functions similarly to the ADDRESS function except that IADDRESS returns an INTEGER_ADDRESS value and does not generate any warning messages Use caution when using IADDRESS Program Correctness Optimization and Efficiency 3 17 Similarly when the parameter to ADDRESS is a formal VAR parameter or a component of a formal VAR parameter the compiler issues a warning message that not all dynamic variables allocated by NEW may be passed to the function For More Information e On attributes and on predeclared routines HP Pascal for OpenV
196. for the rest of the graphics program to begin END In the graphical data model you may wish to define a company logo and you may wish to display that logo on the screen before any other graphical data is drawn or displayed This code declares the variable Initial Shape Since this variable is declared locally to Draw Logo and since Draw Logo is contained in a module that does not produce an environment file other modules that may have access to the interface environment file do not have access to this 2 14 Separate Compilation variable In this application you may not wish to give other compilation units the power to alter the company logo The code in the interfaces TO BEGIN DO section which executes before any program code displays the company logo and deletes it to begin the application Consider again the compilation process for interfaces implementations and programs PASCAL GRAPHICS INTERFACE PASCAL GRAPHICS IMPLEMENTATION PASCAL GRAPHICS MAIN PROGRAM LINK GRAPHICS MAIN PROGRAM GRAPHICS IMPLEMENTATION _S GRAPHICS INTERFACE RUN GRAPHICS MAIN PROGRAM HP Pascal executes the TO BEGIN DO section according to the inheritance order of environment files Remember that HP Pascal cannot determine the order of execution for TO BEGIN DO sections contained in implementation modules so do not use them there Using this design you can allow different sites that run the graphics application to access global data t
197. g Text Libraries on the Command Line The LIBRARY qualifier identifies text libraries specified on the PASCAL command line When you compile a source file that includes a module from a text library concatenate the name of the text library to the name of the source file and append the LIBRARY qualifier You specify concatenation with a plus sign For example PASCAL APPLIC DATAB LIBRARY This command instructs the compiler to search the DATAB text library each time it encounters an INCLUDE directive within the APPLIC source file If more than one library is specified the compiler searches the libraries in the order they appear on the command line For example PASCAL APPLIC DATAB LIBRARY DATAC LIBRARY DATAD LIBRARY If you request multiple compilations the LIBRARY qualifier must appear after each compilation in which it is needed For example PASCAL METRIC DATAB LIBRARY APPLIC DATAB LIBRARY If you are concatenating source files the LIBRARY qualifier can appear only after the last source file For example PASCAL METRIC PAS APPLIC PAS DATAB LIBRARY Any Pascal output qualifiers that appear after the LIBRARY qualifier such as OBJECT or LISTING apply to the last source file name that you specified For example the following PASCAL command creates APPLIC OBJ PASCAL METRIC APPLIC DATAB LIBRARY OBJECT For More Information e On the PASCAL command and qualifiers Section 1 1 1 30 Compiling HP Pascal Programs
198. g the INCLUDE Directive for Text Libraries The INCLUDE directive has the following form INCLUDE file spec module name NOJJLIST file spec The name of the text library containing a module to be included in the compilation module name The name of a text module located in a text library that is to be included in the source file The name of the module must be enclosed in parentheses The module names can include any printable character except a space horizontal tab comma or exclamation point The maximum length of the module name is determined when the text library is created Module names are also case insensitive NO LIST Indicates that the included module should be printed in the listing of the program if a listing is being generated If not specified the default is determined by the NO INCLUDE option on the SHOW qualifier The INCLUDE option enables the listing of INCLUDE files and is enabled by default For example the following INCLUDE directive specifies both the text library DATAB TLB and the module External Declarations INCLUDE DATAB TLB External Declarations If the text library is not specified in the INCLUDE directive its name must appear on the PASCAL command line or it must be specified by a DCL DEFINE command Compiling HP Pascal Programs 1 29 For More Information e On LIST and SHOW qualifiers Section 1 1 2 e On default libraries Section 1 1 4 3 1 1 4 2 Specifyin
199. g the problem INVFILSYN invalid file name syntax Explanation Your program attempted to open a file with an invalid file name The file name used can be derived from the file variable name the value of the file name parameter to the OPEN procedure or the logical name translations if any of the file variable name and portions of the file name parameter and your default device and directory The displayed text may include the erroneous file name This error can also occur if the value of the file name parameter is longer than 255 characters Additional RMS messages may be displayed that further describe the error User Action Use the information provided in the displayed messages to determine which component of the file name is invalid Verify that any logical names used are defined correctly See the HP Pascal for OpenVMS Language Reference Manual for information on file names INVFILVAR invalid file variable at location nnn Explanation The file variable passed to a run time library procedure was invalid or corrupted This problem might be caused by an error in the user program such as an out of bounds array access It can also occur if a file variable is passed from a routine compiled with a version of VAX Pascal earlier than Version 2 0 to a routine compiled with a later version of the compiler or if the new key options are used on OpenVMS systems earlier than Version 4 6 User Action Rerun your program with all CHECK opti
200. gned value that you wish to convert to a negative integer you must use a typecast to perform the operation 9 5 Bound Procedure Values On OpenVMS VAX systems a Bound Procedure Value is a 2 longword data structure holding the address of the entry point and a frame pointer to define the nested environment HP Pascal expects one of these 2 longword structures for PROCEDURE or FUNCTION parameters A routine not written in Pascal needs different code depending on whether it will receive a Bound Procedure Value or a simple routine address When passing routines to IMMED formal routine parameters HP Pascal passes the address of the entry point otherwise it passes the address of a Bound Procedure Value On OpenVMS I64 and OpenVMS Alpha systems a Bound Procedure Value is a special type of procedure descriptor that invokes a hidden jacket routine that in turn initializes the frame pointer and calls the real routine HP Pascal expects a procedure descriptor for PROCEDURE or FUNCTION parameters 9 2 Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha A routine not written in Pascal does not require difference code for Bound Procedure Values When passing routines to IMMED formal routine parameters or asking for the IADDRESS of a routine HP Pascal passes the address of a procedure descriptor as if the IMMED was not present There is no direct way in HP Pascal to obtain the actual code address of a routine because it is not generally us
201. gth parameter when opening the file with the OPEN procedure LINVALEXC LINELIMIT value exceeded Explanation The number of lines written to the file exceeded the maximum specified as the line limit The line limit value is determined by the translation of the logical name PAS LINELIMIT if any or the value specified in a call to the LINELIMIT procedure for the file User Action As appropriate correct the program so that it does not write as many lines or increase the line limit for the file Note that if a line limit is specified for a nontext file each PUT procedure called for the file is considered to be one line See the HP Pascal for OpenVMS Language Reference Manual for more information LOWGTRHIGH low bound exceeds high bound Explanation The lower bound of a subrange definition is larger than the higher bound User Action Modify the declaration so the lower bound is less than or equal to the higher bound MAXLENRNG maximum length must be in range 1 65535 Explanation The maximum length for a string type is 65 535 User Action Modify the declaration to specify a smaller amount MODNEGNUM MOD of a negative modulus has no mathematical definition Explanation In the MOD operation A MOD B the operand B must have a positive integer value User Action Correct the program so that the operand B has a positive integer value Diagnostic Messages C 81 C 82 NEGDIGARG negative Digits argument to BIN HEX or OCT is n
202. he standard switch on the compile command line STDEMPPARM Nonstandard empty actual parameter position Information This message refers to extensions to Pascal and is issued only if you have specified the standard switch on the compile command line C 48 Diagnostic Messages STDEMPREC Nonstandard empty record section Information The Pascal standard does not allow record type definitions of the form RECORD END This message appears only if you have specified the standard switch on the compile command line STDEMPSTR Nonstandard empty string Information This message refers to extensions to Pascal and is issued only if you have specified the standard switch on the compile command line STDEMPVRNT Nonstandard empty variant Information This message occurs if you do not specify a variant between two semicolons or between OF and a semicolon You must also have specified the standard switch on the compile command line STDEOLCOM Nonstandard End of line comment Information The message is issued if you use the exclamation point character to treat the remainder of the line as a comment You must also have specified the standard switch on the compile command line STDERRPARM Nonstandard error recovery parameter STDEXPON Nonstandard exponentiation operator STDEXTSTR Nonstandard extended string syntax Information These messages refer to extensions to Pascal and are issued only if you have specified the standard switch
203. he UNBOUND attribute with 6 14 ADDRESS function effect on optimization 3 17 ALIGN qualifier with PASCAL command 1 3 Alpha emulation 1 6 ANALYSIS DATA qualifier 1 4 ARCHITECTURE qualifier 1 4 Argument pointer saved by routine call 5 5 Assignment with unsupported CDD Repository data type 4 10 ASSUME qualifier 1 7 AST ASTADR parameter 6 16 ASTPRM parameter 6 17 using the UNBOUND attribute with 6 14 ASTADR parameter 6 16 ASTPRM parameter 6 17 AST routine attributes required for 5 6 ASYNCHRONOUS attribute 6 14 in condition handler 8 4 use with system routines 6 6 Index Asynchronous system trap routine See AST routine Atomicity 3 19 Attributes ASYNCHRONOUS 6 14 BYTE use with CDD Repository 4 10 CHECK C 25 ENVIRONMENT 2 1 FLOAT C 25 for by descriptor passing mechanism 5 9 HIDDEN 2 4 INHERIT 2 2 KEY C 25 OPTIMIZE C 25 UNBOUND attribute 6 14 used during OpenVMS programming 6 14 VOLATILE 6 14 Automatic variable in debugging 4 2 Block RMS control 7 1 Bound procedure values 9 2 Branch to longword aligned address 3 11 BRIEF qualifier with MAP on LINK command 1 34 BYTE attribute use with CDD Repository 4 10 Index 1 C Calling block function return value to 5 2 Calling standard 5 1 Call stack contents of 5 4 Call stack OpenVMS Alpha systems contents of 5 5 Call stack OpenVMS I64 systems contents of 5 4 Call stack OpenVMS VAX
204. he fastest code from the compiler Depending on the system use one of the following For OpenVMS I64 systems use PASCAL NOZERO HEAP OPT LEVEL 4 NOCHECK Program Correctness Optimization and Efficiency 3 13 For OpenVMS Alpha systems use PASCAL NOZERO HEAP MATH LIBRARY FAST OPT LEVEL 4 NOCHECK ARCH HOST ASSUME NOACCURACY SENSITIVE For OpenVMS VAX systems use PASCAL OPTIMIZE NOCHECK In both cases you may also want to use the performance flagger to identify datatypes that could be modified for additional performance For More Information e On performance flagger Section 1 1 2 3 2 Programming Considerations The language elements that you use in a source program directly affect the compiler s ability to optimize the resulting object program Therefore you should be aware of the following ways in which you can assist compiler optimization and obtain a more efficient program e Define constant identifiers to represent values that do not change during your program The use of constant identifiers generally makes a program easier to read understand and later modify In addition the resulting object code is more efficient because symbolic constants are evaluated only once at compile time while variables must be reevaluated whenever they are assigned new values e Whenever possible use the structured control statements CASE FOR IF THEN ELSE REPEAT WHILE and WITH rather than the GOTO statement Yo
205. he saved program counter PC The saved contents of other general registers Based on a mask specified in the control information the system restores the saved contents of these registers to the calling routine when control returns to it Calling Conventions 5 5 When execution of a routine ceases the system uses the frame pointer in the call frame of the current routine to locate the frame of the previous routine The system then removes the call frame of the current routine from the stack For More Information e On procedure types and characteristics HP OpenVMS Calling Standard 5 1 4 Unbound Routines The frame pointer of calling routines is stored in an implementation defined register If however you declare a routine with the UNBOUND attribute the system does not assume that the frame pointer of the calling routine is stored in a register and there is no link between the calling and the called routines As a result an unbound routine has the following restrictions e It cannot access automatic variables declared in enclosing blocks e It cannot call bound routines declared in enclosing blocks e It cannot use a GOTO statement to transfer control to enclosing blocks other than the main program block By default routines declared at program or module level and all other routines declared with the INITIALIZE GLOBAL or EXTERNAL attributes have the characteristics of unbound routines Routines passed by the immediate value me
206. her BYTE or LONG The ALIGN qualifier option controls the default record format used by the compiler The ENUMERATION_SIZE qualifier option controls whether the compiler allocates Boolean and enumeration types as longwords or as 1 or 2 bytes On OpenVMS VAX systems the default alignment format is VAX and the default enumeration size is BYTE On OpenVMS I64 and OpenVMS Alpha systems the default alignment format is NATURAL and the default enumeration size is LONG A corresponding pair of attributes can be used at the PROGRAM MODULE level and on VAR and TYPE sections to specify the desired alignment format and enumeration size e ALIGN keyword where keyword is either NATURAL or VAX e ENUMERATION_SIZE keyword where keyword is either BYTE or LONG By using these attributes at the MODULE level you can extract the records into a separate module and create an environment file with the desired alignment format By using these attributes on VAR or TYPE sections you can isolate the records in the same source file 9 7 3 Optimal Record Layout The optimal record layout is one where all the record s fields are naturally sized on naturally aligned boundaries and the overall record is as small as possible for example the fewest number of padding bytes required for proper alignment On OpenVMS 164 and OpenVMS Alpha systems the compiler automatically places all fields of unpacked records on naturally aligned boundaries On OpenVMS VAX sy
207. her programs and binary information passed to a library routine such as an OpenVMS item list You can immediately begin to convert records without external data dependencies into optimal format for example remove any unneeded PACKED keywords and attributes as described earlier You need to classify records with external dependencies further into e Records that cannot be naturally aligned due to a hard dependency that cannot be changed like a record that maps onto an external piece of hardware or a record that is passed to some software you cannot change e Records that can be changed after conversion of binary data or cooperating software Isolate records that you cannot change into their own environment file by using ALIGN VAX ENUM BYTE and FLOAT D_FLOAT You can also attach the ALIGN and ENUMERATION SIZE attributes to the TYPE or VAR sections that define these records In this case you need to also change any uses of the DOUBLE datatype to the D FLOAT datatype to ensure that the proper floating format is used 9 10 Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha You do not need to isolate the record if it uses the PACKED keyword since PACKED records are identical regardless of the ALIGN or ENUM qualifiers Nevertheless isolating the records with dependencies might be useful in the future if you eventually intend to change the format For records that you might change you need to decide whether it is wort
208. hrough the interface module One location can maintain and control the contents of the implementation module shipping the implementation s object module for use at other sites You can use this method for other types of sensitive data or data that needs to be maintained locally Separate Compilation 2 15 2 4 Separate Compilation Examples Example 2 1 shows an interface module that creates the environment file INTERFACE PEN This environment file is inherited in Examples 2 2 and in 2 3 Example 2 1 An Interface Module for Graphics Objects and Routines Source File graphics interface pas This module creates an interface to graphical data and routines ENVIRONMENT interface MODULE Graphics Interface TYPE Shape Types Rectangle Circle Types of graphics objects Shape t Shape Types RECORD Starting coordinate points Coordinate X Coordinate Y REAL VALUE 50 0 CASE t OF Shape specific values Rectangle Height Width REAL VALUE 10 0 Circle Radius REAL VALUE 5 0 END Provide routines that manipulate the shapes PROCEDURE Draw s Shape EXTERNAL PROCEDURE Rotate s Shape EXTERNAL PROCEDURE Scale s Shape EXTERNAL PROCEDURE Delete s Shape EXTERNAL HIDDEN PROCEDURE Draw Logo EXTERNAL Before program execution display a logo to which the main program has no access TO BEGIN DO Draw_Logo END 2 16 Separate Compilation Example 2 2 shows
209. hwhile to convert the record and any external binary data If the record is of low use and you have a large quantity of external data the cost of conversion is probably too high If a record is of high use but is mostly aligned then the conversion also may not be worthwhile However a high use record that is poorly aligned suggests conversion of external data regardless of the amount of effort required There are two types of poorly aligned records e Records that use the PACKED keyword PACKED records lay out the same with either setting of the ALIGN or ENUMERATION SIZE qualifiers To get natural alignment you must remove the PACKED keyword However the keyword PACKED by itself does not guarantee poor alignment For example type t packed record f1 f2 integer end This record is well aligned with or without the PACKED keyword It is also well aligned with ALIGN NATURAL and ALIGN VAX You can remove the PACKED keyword for completeness but nothing else needs to be done e Unpacked records that lay out differently with ALIGN NATURAL and ALIGN VAX These records automatically are well aligned by the compiler when recompiled with ALIGN NATURAL However there are some unpacked records are already well aligned with both alignment formats For example type t record f1 f2 integer end This unpacked record is well aligned with ALIGN NATURAL and ALIGN VAX Nothing else needs to be done to this record The USAGE
210. ic references e Signals an error message for any unresolved symbolic reference 1 2 1 LINK Command Examples This section contains examples of LINK command lines LINK DANCE OBJ CHACHA OBJ SWING OBJ This command links the object files DANCE OBJ CHACHA OBJ and SWING OBJ to produce one executable image called DANCE EXE LINK EXECUTABLE TEST CIRCLE This command links CIRCLE OBJ and then causes the executable image generated by the linker to be named TEST EXE 1 32 Compiling HP Pascal Programs LINK SCHEDULE COURSES INCLUDE HISTORY ALGEBRA PHILOSOPHY This example shows the use of the INCLUDE qualifier with a library named COURSES The linker extracts the modules HISTORY ALGEBRA and PHILOSOPHY from the library COURSES and includes them in the executable image SCHEDULE EXE LINK SCHEDULE COURSES LIBRARY INCLUDE HISTORY ALGEBRA PHILOSOPHY This example also causes the linker to include the modules HISTORY ALGEBRA and PHILOSOPHY in the image file SCHEDULE EXE However the LIBRARY qualifier causes the linker to search the rest of the library COURSES and link in any other modules needed to resolve symbolic references in SCHEDULE HISTORY ALGEBRA and PHILOSOPHY LINK UPDATE EXE PROJECT EXE MAP PROJECT MAP This command produces these files e PROJECT EXEJUPDATE EXE e PROJECT MAP UPDATE MAP For More Information e On debugging Section 4 1 e On error messages Section 1 4 e On including
211. icit ref foreign mechanism specifier to override the formal parameter s type definition and pass our pointer to lib get vm 64 I writeln arr size arr size 1 for i 1 to 10 do begin Stat lib get vm 64 size arr sref ptrarr i if not odd stat then begin writeln Error from lib get vm 64 hex stat lib signal stat end writeln ptrarr i 1 hex ptrarr il end Read write all the memory locations to get some page faults writeln Initialize all memory for i 1 to 10 do for j 1 to arr size do ptrarr i j 2 i j 6 20 Programming on OpenVMS Systems sum 0 writeln Add up all memory in reverse direction for i 10 downto 1 do for j arr_size downto 1 do sum sum ptrarr i j writeln Sum of array contents sum 1 end On OpenVMS I64 and OpenVMS Alpha systems the compiler allows the LONG and QUAD attributes to be specified on pointer types as shown in the following example var long ptr integer quad ptr quad integer Both pointers point to integers but ong ptr is 32 bits while quad ptr is 64 bits Programming on OpenVMS Systems 6 21 7 Input and Output Processing This chapter provides details on the input output I O support provided for OpenVMS systems and discusses the following topics e Section 7 1 Environment I O Support e Section 7 2 User Action Functions e Section 7 3 File Sharing e Section 7 4 Record Locking
212. ide the range of values specified by the type For example this error results if you try to use the SUCC function on the last value in the type or the PRED function on the first value User Action Correct the program so that all ordinal values are within the range of values specified by the ordinal type Diagnostic Messages ORGSPEINC ORGANIZATION specified is inconsistent with this file Explanation The value of the ORGANIZATION parameter for the OPEN procedure that opened an existing file was inconsistent with the actual organization of the file User Action Correct the program so that the correct organization is specified See Chapter 7 for more information PADLENERR PAD length error Explanation The length of the character string to be padded by the PAD function is greater than the length specified as the finished size or the finished size specified is greater than 65 535 User Action Correct the call to PAD so that the finished size specified describes a character string of the correct length See the HP Pascal for OpenVMS Language Reference Manual for the rules governing the PAD function PTRREFNIL pointer reference to NIL Explanation Your program attempted to evaluate a pointer value while its value was NIL User Action Make sure that the pointer has a value before you try to evaluate it See the HP Pascal for OpenVMS Language Reference Manual for more information on pointer values RECLENINC RECORD LENGTH
213. ilation units without the other units having to worry about implementation details The actual details are contained in one implementation module For example the routine bodies are contained in the implementation module Consider the following code fragment from Example 2 2 Declare routine bodies for declarations in the interface GLOBAL PROCEDURE Draw s Shape BEGIN CASE s t OF Circle WRITELN Code that draws a circle Rectangle WRITELN Code that draws a rectangle END END Procedure Draw The routine bodies of the external routines declared in the interface module are located in the implementation module The code in each of the routines uses the actual discriminant of parameter s to determine if the shape is a circle or a rectangle and draws the shape If this code needs to change it does not require that you recompile the code in Examples 2 1 or 2 3 in Section 2 4 Example 2 2 also contains code that is isolated and hidden from other compilation units that inherit the interface environment file Consider the following code fragment from the interface module GLOBAL PROCEDURE Draw Logo VAR Initial Shape Shape Circle Declare object VALUE Coordinate X 50 0 Coordinate Y 50 0 CASE Circle OF Radius 15 75 BEGIN WRITELN Drawing a company logo Draw Initial Shape Code pauses for 30 seconds as the user looks at the logo Delete Initial Shape WRITELN Ready
214. ile sharing read sharing and write sharing Read sharing occurs when several programs are reading a file at the same time Write sharing takes place when at least one program is writing a file and at least one other program is either reading or writing the same file The extent to which file sharing can take place is determined by the following factors e Device type Sharing is possible only on disk files since other files must be accessed sequentially e File organization All three file organizations permit read and write sharing on disk files e Explicit user supplied information Whether or not file sharing actually takes place depends on two items of information that you provide for each program accessing the file In HP Pascal programs this information is supplied by the values of the SHARING and HISTORY parameters in the OPEN procedure The HISTORY parameter determines how the program will access the file HISTORY NEW HISTORY OLD and HISTORY UNKNOWN determine that the program will read from and write to the file HISTORY READONLY determines that the program will only read from the file If you try to open an existing file with HISTORY OLD or HISTORY UNKNOWN the run time library retries the OPEN procedure with HISTORY READONLY if the initial OPEN fails with a privilege violation The SHARING parameter determines what other programs are allowed to do with the file Read sharing can occur when SHARING RE
215. ile time known size Error You cannot specify an immediate passing mechanism for a conformant parameter or a formal parameter of type VARYING OF CHAR Diagnostic Messages C 23 INCMPBASE Incompatible with SET base type Error If no type identifier denotes the base type of a set constructor the first element of the constructor determines the base type The type of all subsequent elements specified in the constructor must be compatible with the type of the first INCMPFLDS Record fields are not the same type Error INCMPOPND Incompatible operand s Error The types of one or more operands in an expression are not compatible with the operation being performed INCMPPARM Incompatible routine parameter Error An actual routine parameter is incompatible with the corresponding formal parameter INCMPTAGTYP Incompatible variant tag types Error This message can appear as additional information on other error messages INCTOODEEP INCLUDE directives nested too deeply ignored Error A program cannot include more than five levels of files with the 9 INCLUDE directive The compiler ignores INCLUDE files beyond the fifth level INDNOTORD Index type must be an ordinal type Error The index type of an array must be an ordinal type INFO INFO Information This message is generated by the INFO directive INITNOEXT INITIALIZE routine may not be EXTERNAL INITNOFRML INITIALIZE routine must have no formal para
216. imizations which can be detected only by a careful examination of the machine code produced by the compiler Global assignment of variables to registers If possible reduce the number of memory references needed by assigning frequently referenced variables to registers Reordering the evaluation of expressions This minimizes the number of temporary values required Peephole optimization of instruction sequences The compiler examines code a few instructions at a time to find operations that can be replaced by shorter and faster equivalent operations For More Information On HP Pascal language elements HP Pascal for OpenVMS Language Reference Manual 3 2 Program Correctness Optimization and Efficiency 3 1 1 Compile Time Evaluation of Constants The compiler performs the following computations on constant expressions at compile time Negation of constants The value of a constant preceded by unary minus signs is negated at compile time For example x se 10 0 Type conversion of constants The value of a lower ranked constant is converted to its equivalent in the data type of the higher ranked operand at compile time For example x 10 y If x and y are both real numbers then this operation is compiled as follows x 10 0 y Arithmetic on integer and real constants An expression that involves or operators is evaluated at compile time For example CONST nn 27 In the executable sect
217. in routine that calls LIB SIG_TO RET and then returns SS RESIGNAL You cannot establish LIB SIG TO RET directly as a handler with the ESTABLISH built in routine e Ifyou are moving code from OpenVMS VAX to OpenVMS I64 or OpenVMS Alpha Error Processing and Condition Handling 8 9 On OpenVMS VAX systems only certain run time errors are not allowed to return SS CONTINUE from a handler These errors are those associated with the SUBSTR and PAD built in routines and those associated with checking code for set constructors On OpenVMS I64 and OpenVMS Alpha systems many more run time errors are not allowed to return SS CONTINUE from a handler It is recommended that you do not return SS CONTINUE for any Pascal run time error that is not associated with a file operation For More Information e On the format of a condition value HP OpenVMS Calling Standard e On calling the LIBBMATCH COND function Section 8 5 8 4 Fault and Trap Handling OpenVMS VAX systems If a VAX processor detects an error while executing a machine instruction it can take one of two actions The first action called a fault preserves the contents of registers and memory in a consistent state so that the instruction can be restarted The second action called a trap completes the instruction but with a predefined result For example if an integer overflow trap occurs the result is the correct low order part of the true value The action taken when an except
218. ing WRITELN Explanation RMS reported an unexpected error during execution of the WRITELN procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the RMS error EXTNOTALL EXTEND is not allowed for a shared file Explanation Your program attempted an EXTEND procedure for a file for which the program did not have exclusive access EXTEND requires that no other users be allowed to access the file Note that this message may also be issued if you do not have permission to extend to the file User Action Correct the program so that the file is opened with SHARING zNONE which is the default before performing an EXTEND procedure FAIGETLOC failed to GET locked component Explanation Your program attempted to access a component of a file that was locked by another user You can usually expect this condition to occur when more than one user is accessing the same relative or indexed file User Action Determine whether this condition should be allowed to occur If so modify your program so that it detects the condition and retries the operation later See Chapter 7 for more information Diagnostic Messages C 71 C 72 FILALRACT file file name is already active Explanation Your program attempted a file operation on a file for which another operation was still in progress This error can occur if a file is used in AST or condition h
219. int support is implemented by converting the VAX floating format values to IEEE format performing the operation and converting the result back to VAX floating format Because of the conversion some programs might get slightly different results for F floating D floating and G floating computations than they produce on OpenVMS Alpha and OpenVMS VAX systems OpenVMS VAX systems do not support eFLOAT IEEE FLOAT file spec LIBRARY none default Specifies that a file is a text library file The text library file specification is required The text library files in a list of source files must be concatenated by plus signs The default file type is TLB GRANULARITY keyword Directs the compiler to generate additional code to preserve the indicated granularity Granularity refers to the amount of storage that can be modified when updating a variable You can specify the following values for keyword e BYTE e LONGWORD e QUADWORD default To update a variable that is smaller than a longword on older Alpha systems HP Pascal must issue multiple instructions to fetch the surrounding longword or quadword update the memory inside to longword or quadword and then write the longword or quadword back into memory If multiple processes are writing into memory that is contained in the same longword or quadword you might incur inaccurate results unless GRANULARITY BYTE or some other synchronization mechanism is used On newer Alpha systems
220. ion e On passing mechanisms and passing semantics Section 5 3 4 5 3 1 By Immediate Value The by immediate value passing mechanism passes a copy of a value instead of the address HP Pascal provides the IMMED foreign passing mechanism and the IMMEDIATE attribute in order to pass a parameter by immediate value You cannot use variable semantics with the by immediate value passing mechanism On OpenVMS 164 and OpenVMS Alpha systems values that are less than or equal to 64 bits in size can be passed by immediate value On OpenVMS VAX systems values that are less than or equal to 32 bits in size can be passed by immediate value 5 3 2 By Reference The by reference mechanism passes the address of the parameter to the called routine This is the default parameter passing mechanism for non conformant and non schematic parameters When using the by reference mechanism the type of passing semantics used depends on the use of the VAR keyword If the formal parameter name is preceded by the reserved word VAR variable semantics is used otherwise value semantics is used In addition to using the defaults the HP Pascal compiler provides the REF foreign passing mechanism and the REFERENCE attribute which has more than one interpretation for the passing semantics depending on the data item represented by the actual parameter This allows you to have the called routine use either variable semantics or true foreign semantics The mechan
221. ion i 2 nmne jg This is compiled as follows i 54 j Array address calculations involving constant indexes These are simplified at compile time whenever possible For example VAR i ARRAY 1 10 1 10 OF INTEGER In the executable section i 1 2 1 4 5 Evaluation of constant functions and operators Arithmetic ordinal transfer unsigned allocation size CARD EXPO and ODD functions involving constants concatenation of string constants and logical and relational operations on constants are evaluated at compile time Program Correctness Optimization and Efficiency 3 3 For More Information e On the complete list of compile time operations and routines HP Pascal for OpenVMS Language Reference Manual 3 1 2 Elimination of Common Subexpressions The same subexpression often appears in more than one computation within a program For example ace b tote f h aeg b c IF b c h lt gt 0 THEN In this code sequence the subexpression b c appears three times If the values of the operands b and c do not change between computations the value b c can be computed once and the result can be used in place of the subexpression The previous sequence is compiled as follows t b o a tt e f h satg t IF t h lt gt 0 THEN Two computations of b c have been eliminated In this case you could have modified the source program itself for greater program optimization The
222. ion run time library routines return one or two values the result of a computation or the routine s completion status or both When the routine returns a completion status you should verify the return status before checking the result of a computation You can use the function ODD to test for success or failure or you can check for a particular return status by comparing the return status to one of the status codes defined by the system For example VAR Seed Value INTEGER Rand Result REAL ASYNCHRONOUS FUNCTION MTHSRANDOM VAR seed VOLATILE UNSIGNED SINGLE EXTERNAL In the executable section Rand Result MTHSRANDOM Seed Value When the routine s completion status is irrelevant your program can treat the function as though it were an external procedure and ignore the return value For example your program can declare the Hibernate SYS HIBER system service as a function but call it as though it were a procedure ASYNCHRONOUS EXTERNAL SYS HIBER FUNCTION SHIBER INTEGER EXTERNAL In the executable section SHIBER Put process to sleep Because SYS HIBER is expected to execute successfully the program will ignore the integer condition value that is returned Programming on OpenVMS Systems 6 13 6 4 Using Attributes When writing programs that use OpenVMS System Services and run time library routines it is common to use several HP Pascal attributes The VOLATILE attribute indicates that
223. ion Functions The user action parameter of the OPEN procedure allows you to access RMS facilities not explicitly available in the HP Pascal language by writing a function that controls the opening of the file Inclusion of the user action parameter causes the run time library to call your function to open the file instead of calling RMS to open it according to its normal defaults The user action parameter of the CLOSE procedure is similar to that of the OPEN procedure It allows you to access RMS facilities not directly available in HP Pascal by writing a function that controls the closing of the file Including the user action parameter causes the run time library to call your function to close the file instead of calling RMS to close it according to its normal defaults When an OPEN or CLOSE procedure is executed the run time library uses the procedure s parameters to establish the RMS file access block FAB and the record access block RAB as well as to establish its own internal data structures These blocks are used to transmit requests for file and record 7 10 Input and Output Processing operations to RMS they are also used to return the data contents of files information about file characteristics and status codes In order the three parameters passed to a user action function by the run time library are as follows e FAB address e RAB address e File variable A user action function is usually written in HP Pascal and in
224. ion occurs depends on the type of exception For example faults occur for access violations and for detection of a floating reserved operand Traps occur for integer overflow and for integer divide by zero exceptions However when a floating overflow floating underflow or floating divide by zero exception occurs the action taken depends on the type of VAX processor executing the instruction The original VAX 11 780 processor traps when these errors occur and stores a floating reserved operand in the destination All other VAX processors fault on these exceptions which allows the error to be corrected and the instruction restarted If your program is written to handle floating traps but runs on a VAX processor that generates faults execution may continue incorrectly For example if a condition handler causes execution to continue after a floating trap a reserved operand is stored and the next instruction is executed However the same handler used on a processor that generates faults causes an infinite loop of faults because it restarts the erroneous instruction Therefore you should write floating point exception handlers that take the appropriate actions for both faults and traps 8 10 Error Processing and Condition Handling Separate sets of condition values are signaled by the processor for faults and traps Exceptions and their condition code names are as follows Exception Fault Trap Floating overflow SS FLTOVF F SS FLTOVF
225. ions Mechanism Description By immediate value The argument contains the value of the data item By reference The argument contains the address of the data to be used by the routine By descriptor The argument contains the address of a descriptor which describes type of the data and its location By default HP Pascal uses the by reference mechanism to pass all actual parameters except those that correspond to conformant parameters and undiscriminated schema parameters in which case the by descriptor mechanism is used Table 5 2 describes the syntax you use in HP Pascal to obtain the desired parameter passing mechanism Table 5 2 Parameter Passing Syntax on HP Pascal Mechanism Syntax Used by HP Pascal By immediate value IMMED or IMMEDIATE By reference Default for nonconformant and nonschema parameters or 2 REF By descriptor Default for conformant and schema parameters or DESCR STDESCR CLASS S ICLASS AJ or CLASS NCA A mechanism specifier usually appears before the name of a formal parameter or if a passing attribute is used it appears in the attribute list of the formal Calling Conventions 5 7 parameter However in HP Pascal a mechanism specifier can also appear before the name of an actual parameter In the latter case the specifier overrides the type passing semantics passing mechanism and the number of formal parameters specified in the formal parameter declaration For More Informat
226. ironment file that is inherited by both the implementation module and by the program Figure 2 2 shows the inheritance process Separate Compilation 2 7 Figure 2 2 Inheritance Path of an Interface an Implementation and a Program Interface Module Implementation Program Module means is inherited by ZK 1491A GE Consider this code fragment from the interface module in Example 2 1 see Section 2 4 ENVIRONMENT interface MODULE Graphics Interface OUTPUT Globally accessible type Provide routines that manipulate the shapes PROCEDURE Draw S Shape EXTERNAL PROCEDURE Rotate s Shape EXTERNAL PROCEDURE Scale s Shape EXTERNAL PROCEDURE Delete s Shape EXTERNAL Module initialization section END The code contained in the interface is not likely to change often The implementation code can change without requiring recompilation of the other modules in the application Consider this code fragment from the implementation module in Example 2 2 see Section 2 4 2 8 Separate Compilation INHERIT Interface Predeclared graphics types and routines MODULE Graphics Implementation OUTPUT GLOBAL PROCEDURE Rotate s Shape BEGIN WRITELN Rotating the shape s t END To compile link and run the code in Examples 2 1 2 2 and 2 3 the main program use the following commands PASCAL GRAPHICS INTERFACE PASCAL GRAPHICS IMPLEMENTATIO
227. ism specifier appears before the name of a formal parameter The parameter passing attribute appears in the attribute list of the formal parameter 5 8 Calling Conventions 5 3 3 By Descriptor There are several types of descriptors Each descriptor contains a value that identifies the descriptor s type The called routine then uses the information held in the descriptor to identify its type and size This is the default parameter passing mechanism for conformant and schematic parameters When you use one of the HP Pascal by descriptor mechanisms the compiler passes the address of a string array or scalar descriptor The HP Pascal compiler generates the descriptor supplying the necessary information HP Pascal provides three attributes for the by descriptor passing mechanism CLASS S CLASS A and CLASS NCA With these three attributes the type of passing semantics used for the by descriptor argument depends on the use of the VAR keyword If the formal parameter name is preceded by the reserved word VAR variable semantics is used otherwise value semantics is used The parameter passing attribute appears in the attribute list of the formal parameters Sometimes you may want to choose either variable semantics or true foreign semantics In these cases the HP Pascal compiler provides two foreign passing mechanism specifiers DESCR and STDESCR These specifiers have more than one interpretation for the passing semantics depending on
228. itance path Figure 2 1 Cascading Inheritance of Environment Files Problematic Efficient Inherited by ZK 1469A GE Cascading is not always undesirable it depends on your application and on the nature of the environment files For example if cascading occurs for a series of constant and type definitions that are not likely to change cascading may require very little recompiling and relinking However if the constant and type definitions change often or if environment files contain routines and variables you may find it easier to redesign the inheritance paths of environment files due to the recompiling and relinking involved Separate Compilation 2 3 Also the inheritance path labeled Efficient in Figure 2 1 is not immune to misuse That inheritance path although it avoids the problems of cascading may still involve multiply declared identifiers identical identifiers contained in several of the compilation units whose environment files are inherited by compilation unit 4 In many instances HP Pascal does not allow multiply declared identifiers in one application For example a compilation unit cannot inherit two environment files that declare the same identifier also a compilation unit usually cannot inherit an environment file that contains an identifier that is identical to an identifier in the outermost level of the unit one exception for example is the redeclaration of a redefinable reserved word or of an i
229. ition handler with 8 5 LIB FIND FILE routine Resultant Filespec parameter 6 17 LIB MATCH COND function 8 8 LIB SIGNAL procedure signaling condition with 8 3 LIB SIM TRAP procedure 8 11 LIB STOP procedure signaling condition with 8 3 Index 5 LIBDEF PAS definition file 6 3 Library object module 1 36 of shareable images 1 35 text 1 29 LIBRARY qualifier 1 14 with LINK command 1 34 LINELIMIT procedure 7 10 LINK command 2 2 examples of 1 32 qualifiers for 1 33 to 1 35 relinking implementation modules 2 9 syntax of 1 31 TO BEGIN DO execution order 2 15 Linker including shareable image as input to 1 35 LIST attribute with run time library routine 6 12 Listing file compilation statistics 1 28 cross reference section 1 27 inline summary 1 28 machine code section 1 27 OpenVMS VAX systems 1 26 printing of 1 26 source code 1 27 table of contents 1 27 Listing section structured layout 1 28 LIST qualifier 1 15 use with DICTIONARY directive 4 9 Locked record 7 15 in indexed file 7 15 in relative file 7 15 unlocking 7 15 Logical expression optimization of 3 8 LONG on pointer types 6 21 Loop See Infinite Loop Loop unrolling 3 10 LSE comment processing example of 4 6 Index 6 LSE cont d example of use within program 4 5 to 4 8 HP Pascal support of for keywords or tokens 4 3 placeholder processing 4 3 placeholder processing example of 4 6
230. l for OpenVMS Language Reference Manual On procedure calling and argument passing mechanisms HP OpenVMS Calling Standard 5 1 OpenVMS Calling Standard Programs compiled by the HP Pascal compiler conform to the OpenVMS calling standard This standard describes how parameters are passed how function values are returned and how routines receive and return control Because HP Pascal conforms to the calling standard you can call and pass parameters to routines written in other Hewlett Packard languages from HP Pascal programs For More Information See the HP OpenVMS Calling Standard Calling Conventions 5 1 5 1 1 Parameter Lists Each time a routine is called the HP Pascal compiler constructs a parameter list On OpenVMS I64 systems the parameters are a sequence of quadword 8 byte entries The first 8 integer parameters are located in integer registers designated as R32 to R39 the first 8 floating point parameters are located in floating point registers designated as F8 to F15 Information about the parameter list is passed in the argument information register R25 The first byte of the register specifies the parameter count Arguments beyond 8 are passed on the stack starting at offset 16 On OpenVMS Alpha systems the parameters are a sequence of quadword 8 byte entries The first 6 integer parameters are located in integer registers designated as R16 to R21 the first 6 floating point parameters are located in floa
231. l procedure x in some other module that also inherits INTERFACE PEN before the creation and initialization of the variable My_String You can circumvent this problem by using a routine call to initialize the variable and by moving the code to the interface module as shown in the next example In one file ENVIRONMENT interface MODULE Interface VAR My String STRING 10 PROCEDURE x EXTERNAL PROCEDURE Initialize EXTERNAL TO BEGIN DO Initialize END Separate Compilation 2 11 In another file INHERIT interface MODULE Implementation OUTPUT GLOBAL PROCEDURE x BEGIN WRITELN My String END GLOBAL PROCEDURE Initialize BEGIN My String Okay END END 2 3 Data Models Using separate compilation and a few other features of HP Pascal including initial states constructors the HIDDEN attribute and TO BEGIN DO and TO END DO sections you can construct models for creating distributing isolating and restricting data in an application Of course the design of the data model depends on the needs of a particular application However to show some of the power of HP Pascal features used in conjunction Examples 2 1 2 2 and 2 3 in Section 2 4 create a generic graphics application Consider the following code fragment from Example 2 1 TYPE Shape Types Rectangle Circle Types of graphics objects Shape t Shape Types RECORD Starting coordinate point
232. language has several implementation dependent behaviors that a program must not rely upon Relying on these behaviors for correct behavior is illegal and is not portable to other platforms or other compiler versions Refer to the HP Pascal for OpenVMS Language Reference Manual for a list of the implementation dependent behaviors For More Information e On attributes and on static and automatic variables HP Pascal for OpenVMS Language Reference Manual e On compilation switches Chapter 1 3 3 4 Subexpression Evaluation Order The compiler can evaluate subexpressions in any order and may even choose not to evaluate some of them Consider the following subexpressions that involve a function with side effects IF f a AND f b THEN This IF statement contains two designators for function f with the same parameter a If f has side effects the compiler does not guarantee the order in which the side effects will be produced In fact if one call to f returns FALSE the other call to f might never be executed and the side effects that result from that call would never be produced For example q f a f a The Pascal standard allows a compiler to optimize the code as follows Q im 2 El a If the compiler does so and function f has side effects the side effects would occur only once because the compiler has generated code that evaluates f a only once If you wish to ensure left to right evaluation with short circuiting u
233. language specific condition handler that in turn allows your handler to be called User written condition handlers set up by ESTABLISH must have the ASYNCHRONOUS attribute and two integer array formal parameters Such routines can access only local read only and volatile variables and local predeclared and asynchronous routines 8 4 Error Processing and Condition Handling Because condition handlers are asynchronous any attempt to access a nonread only or nonvolatile variable declared in an enclosing block will result in a warning message The predeclared file variables INPUT and OUTPUT are such nonvolatile variables therefore simultaneous access to these files from both an ordinary program and from an asynchronous condition handler s activation may have undefined results The following steps outline the recommended method for performing I O operations from a condition handler 1 Declare a file with the VOLATILE attribute at program level 2 Open this file to refer to SYS INPUT SYS OUTPUT or another appropriate file 3 Use this file in the condition handler External routines including system services that are called by a condition handler require the ASYNCHRONOUS attribute in their declaration You should set up a user written condition handler with the predeclared procedure ESTABLISH rather than with the run time library routine LIB ESTABLISH ESTABLISH follows the HP Pascal procedure calling rules and is able to handle HP
234. larity Warning Due to poor alignment the code generator is unable to generate a code sequence for the granularity requested Diagnostic Messages C 33 NOREPRE No textual representation for values of this type Error You cannot write a value to a text file using WRITE or WRITELN or to a VARYING string using WRITEV if there is no textual representation for the type Similarly you cannot read a value from a text file using READ or READLN or from a VARYING string using READVYV if there is no textual representation for the type Such types are RECORD ARRAY other than PACKED ARRAY 1 n OF CHAB SET and pointer NOTAFUNC symbol name is not declared as a routine Error An identifier followed by a left parenthesis a semicolon or one of the reserved words END UNTIL and ELSE is interpreted as a call to a routine with no parameters This message is issued if the identifier was not declared as a procedure or function identifier Note that in the current version functions can be called with the procedure call statement NOTASYNCH routine name is not ASYNCHRONOUS Information This message can appear as additional information on other error messages NOTATAG identifier is not a tag identifier Error The identifier used with the CASE OF construct in a record constructor must be a tag identifier NOTATYPE symbol name is not a type identifier Error An identifier that does not represent a type was used i
235. lders as well as tokens LSE supplies language constructs for these keywords when they appear on your screen as placeholders You can also type the keywords into the buffer yourself enter the EXPAND command and see the same language constructs appear on your screen You can use the SHOW TOKEN and SHOW PLACEHOLDER commands to display a list of all HP Pascal tokens and placeholders or a particular token or placeholder For example LSE SHOW TOKEN IF lists the token IF LSE SHOW TOKEN lists all tokens To copy the listed information into a separate file first enter the appropriate SHOW command to put the list into the SHOW buffer Then enter the following command LSE GOTO BUFFER SHOW LSE SAVE FILE filename filetype 4 2 2 Placeholder and Design Comment Processing While all languages with LSE support provide placeholder processing each language defines specific contexts in which placeholders can be accepted as valid program code HP Pascal defines contexts for declaration section placeholders and executable section placeholders Table 4 1 lists the valid contexts within an HP Pascal declaration section where you can insert placeholders Programming Tools 4 3 Table 4 1 Placeholders Within the Declaration Section Can Replace Cannot Replace PROGRAM or Directive MODULE identifier Program parameter Attribute Identifier Declaration begin reserved word Data type Complete declaration Value Complete variant withi
236. le the number of symbols actually used by the compilation and the percentage of used symbols versus defined symbols Note that the HP Pascal compiler defines symbol in terms of internal representation This definition can not reflect the complexity of the environment source that is the number of symbols shown loaded can not reflect the number of symbols in your program e Command Qualifiers and Options List containing the exact command line passed by DCL to the HP Pascal compiler and the qualifier options in effect during compilation e Compiler Internal Timing Statistics noting the number of page faults and amount of elapsed time and CPU time required for each phase of the compilation e Compilation Statistics listing the total number of messages generated at each level informational warning error and fatal the time and speed of compilation and the number of page faults that occurred The last line is a message indicating that the compilation of the source code is complete 1 28 Compiling HP Pascal Programs 1 1 4 Text Libraries 1 1 4 1 A text library contains modules of source text that you can incorporate in a program by using the INCLUDE directive This directive indicates the module and optionally the text library in which the module can be found Text library names can be specified in the following ways e Inthe INCLUDE directive e On the PASCAL command line e Ina DEFINE default library command DCL Usin
237. le time checking for users of this environment file e NONE Separate Compilation 2 5 Disables all compile time checking for users of this environment file When HP Pascal compiles a module with the ENVIRONMENT qualifier or ENVIRONMENT attribute it generates an environment file and an object file This is also true when compiling a or program although it is not customary to generate an environment from a program The PEN file contains compressed symbol table information and is used by subsequent Pascal compilations with the INHERIT attribute Neither the OpenVMS Linker or ANALYZE OBJECT reads environment files Only the HP Pascal compiler uses these files The OBJ file contains the following e Storage for variables declared at the outermost level of the module e Code for procedures functions contained in the module e Linker timestamp verification for all inherited environment files and for the environment file being created e Compiler generated variables and routines to support schema types declared or discriminated at the outermost level of the module e Code for the TO BEGIN DO or TO END DO sections the module will have an invisible TO BEGIN DO section if it inherits an environment whose creating module also had a TO BEGIN DO or TO END DO section It is possible for the OBJ file to contain just the linker timestamp record for the environment being created Since the linker does not require the timestamp record for correct
238. loc Quantity FAB FABSL ALQ User Open Status END Function User Open FUNCTION User Create VAR FAB FABSTYPE VAR RAB RABSTYPE VAR F FType INTEGER VAR Status INTEGER BEGIN Function User Create Set up contiguous allocation FAB FABSL_ALQ v Alloc Quantity FAB FABSV_CBT FALSE FAB FABSV_CTG TRUE Status SCREATE FAB IF ODD Status THEN Status SCONNECT RAB User Create Status END Function User Create continued on next page 7 12 Input and Output Processing Example 7 1 Cont User Action Function EGIN main program Open files PEN F In HISTORY READONLY USER ACTION User Open ESET F In PEN F Out HISTORY NEW USER ACTION User Create EWRITE F Out Copy F In to F Out HILE NOT EOF F In DO BEGIN WRITE F Out F In GET F In END zmi JH OpBo u Close files CLOSE F In CLOSE F Out END main program In this example the record types FAB TYPE and RAB TYPE are defined in SYS LIBRARY STARLET which the program inherits The function User Open is called as a result of the OPEN procedure for the input file F In The function begins by opening the file with the RMS service OPEN If 0PEN succeeds the value of Status is odd in that case CONNECT is performed The allocation quantity contained in the FAB FAB L_ALQ field of the FAB is assigned to a variable so that this value can b
239. lowed on a record field CNTBEREFPARM Not allowed on a parameter passed by a reference passing mechanism CNTBERTNDECL Not allowed on a routine declaration CNTBERTNPARM Not allowed on a routine parameter CNTBESCHEMA Not allowed on a nonstatic type CNTBESETRNG Not allowed on a set range CNTBESTDPARM Not allowed on a STDESCR foreign mechanism parameter CNTBETAGFLD Not allowed on a variant tag field CNTBETAGTYP Not allowed on a variant tag type CNTBETO Not allowed on TO BEGIN END DO CNTBETYPDEF Not allowed on a type definition NTBETYPE Not allowed on a TYPE definition part NTBEVALPARM Not allowed on a value parameter NTBEVALUE Not allowed on a VALUE initialization part NTBEVALVAR Not allowed on a VALUE variable NTBEVAR Not allowed on a VAR declaration part NTBEVARBLE Not allowed on a variable QAaQaQaagagg C 12 Diagnostic Messages CNTBEVARPARM Not allowed on a VAR parameter CNTBEVRYCMP Not allowed on a varying component Information These messages can appear as additional information on other error messages COMCONFLICT COMMON block name conflicts with another COMMON or PSECT of same name Error You can allocate only one variable in a particular common block and the name of the common block cannot be the same as the names of other common blocks or program sections used by your program COMNOTALN Component is not optimally aligned Information The component indicated is not well aligned and acces
240. lpha systems only PSECT MODEL NOMULTILANGUAGE default This qualifier controls whether the compiler pads the size of overlaid PSECTs so as to ensure compatibility when the PSECT is shared by code created by other OpenVMS Alpha compilers When a PSECT generated with a COMMON attribute is overlaid with a PSECT consisting of a C struct or a Fortran COMMON block linker error messages can result due to the inconsistent sizes of the PSECTs some languages pad the size of PSECTS while other do not 1 18 Compiling HP Pascal Programs NOJSHOW SHOW DICTIONARY HEADER INCLUDE SOURCE STATISTICS TABLE OF CONTENTS default Specifies a list of items to be included in the listing file A single identifier or a list of identifiers enclosed in parentheses can follow SHOW these identifiers are the names of options that inform the compiler which type of information it should generate Table 1 10 lists the available options their corresponding actions and their negations Table 1 10 SHOW Qualifier Options Option Action Negation ALL Enables listing of all options NONE DICTIONARY Enables listing of 7DICTIONARY NODICTIONARY records HEADER Enables page headers NOHEADER INCLUDE Enables listing of INCLUDE NOINCLUDE files INLINE OpenVMS Enables listing of inline NOINLINE VAX systems only summary SOURCE Enables listing of HP Pascal NOSOURCE source code STATISTICS Enables listing of compilation NOSTATISTICS statistics
241. lt library by using the DCL command DEFINE The linker searches default user libraries for unresolved references after it searches modules and libraries specified in the LINK command For More Information e On the LINK command and qualifiers Section 1 2 On the OpenVMS Linker HP OpenVMS Linker Utility Manual e On the DCL command DEFINE HP OpenVMS DCL Dictionary 1 36 Compiling HP Pascal Programs 1 3 RUN Command The RUN command executes programs that have been linked into an executable image by the OpenVMS Linker This command has the following format RUN command qualifier file spec command qualifier The name of a qualifier that indicates special processing to be performed by the linker on all files listed file spec The name of the executable image you want to run The default file type for executable images is EXE The image activator accepts one command qualifier as follows NO DEBUG depends on linking default The NO DEBUG qualifier is optional Specify the DEBUG qualifier to request the debugger if the image was not linked with it You cannot use DEBUG on images linked with the NOTRACEBACK qualifier If the image was linked with the DEBUG qualifier and you do not want the debugger to prompt use the NODEBUG qualifier The default action depends on whether you specified DEBUG on the LINK command line Consider the following examples RUN PROG This example executes the image PROG EXE If y
242. mand LSE 4 3 Extended attribute block See XAB Extensions to standard Pascal detecting 1 20 EXTERNAL attribute compared with UNBOUND 5 6 effect on routine call 5 6 External routine declaration example of 6 4 F Fault condition handling for 8 10 converting to trap 8 11 Fetch with unsupported CDD Repository data type 4 10 Field initial state specifier for 2 12 File locked component in 7 15 sharing 7 14 File access block See FAB File component locked 7 15 File type of environment file 1 13 of listing file 1 15 of object file 1 16 FLOAT attribute C 25 FLOAT qualifier 1 13 Foreign mechanism parameters 5 15 Foreign mechanism specifier 6 16 FOR statement effect on efficiency 3 14 Frame pointer of unbound routine 5 6 saved by routine call 5 5 FULL qualifier with MAP on LINK command 1 34 Function methods of returning result 5 2 optimization of 3 6 user action 7 10 G FAB access to B 1 fields when calling OPEN 7 5 passed as parameter by run time library 7 10 used to write user action functions 7 1 Index 4 GLOBAL attribute compared with UNBOUND 5 6 effect on routine call 5 6 GOTO statement effect on efficiency 3 14 Granularity 3 19 GRANULARITY qualifier 1 14 H HELP LANGUAGE command debugger 4 1 HIDDEN attribute 2 4 HISTORY parameter use when accessing files 7 14 HP OpenVMS Calling Standard 5 1 T O processing 7 1 to 7 16 I
243. mber values WRITEONLY variable name is WRITEONLY Warning You cannot use a write only variable in any context that requires the variable to be evaluated For example a write only variable cannot be used as the control variable of a FOR statement C 64 Diagnostic Messages XTRAERRORS Additional diagnostics occurred on this line Information The number of errors occurring on this line exceeds the implementation s limit for outputting errors You should correct the errors given and recompile your program ZERNOTALL ZERO is not allowed for type or types containing type name Error ZERO may not be used to initialize objects of type FILE TEXT or TIMESTAMP or objects containing these types C 2 Run Time Diagnostics During execution an image can generate a fatal error called an exception condition When the HP Pascal run time system detects such a condition the system displays an error message and aborts program execution Run time errors can also be issued by other facilities such as the OpenVMS Sort Utility or the OpenVMS operating system HP Pascal run time system diagnostics are preceded by the following SPAS F The severity level of a run time error is F fatal error Some conditions particularly I O errors may cause several messages to be generated The first message is a diagnostic that specifies the file that was being accessed if any when the error occurred and the nature of the error Next an RMS error m
244. meter declaration syntax Information The declaration of a formal routine parameter uses the obsolete VAX Pascal Version 1 0 syntax You should edit your program to incorporate the current version syntax which is mandated by the Pascal standard OPNDASSCOM Operands are not assignment compatible OPNOTINT Operand s must be of type integer Error OPNDNAMCOM Operands are not name compatible Error ORDOPNDREQ Ordinal operand s required Error or Warning This message is at warning level if you try to use INT ORD or UINT on a pointer expression It is at error level if you use PRED or SUCC on an expression whose type is not ordinal OUTNOTDECL OUTPUT not declared in heading Error A call to EOF EOLN READLN or WRITELN did not specify a file variable and the default INPUT or OUTPUT was not listed in the program heading OVRDIVZERO Overflow or division by zero in compile time expression Error Diagnostic Messages C 37 PACKSTRUCT component name of a PACKED structured type Error or Warning You cannot use the data items listed in a call to the ADDRESS function nor can you pass them as writable VAR REF DESCR or STDESCR parameters This message is at warning level if the variable or component has the UNALIGNED attribute and at error level if the variable or component is actually unaligned PARMACTDEF Formal parameter parameter name has neither actual nor default Error If a formal parameter is not declar
245. meter list Error INITSYNVAR Illegal initialization syntax Use VALUE Error C 24 Diagnostic Messages INPNOTDECL INPUT not declared in heading Error A call to EOF EOLN READLN or WRITELN did not specify a file variable and the default INPUT or OUTPUT was not listed in the program heading INSTNEWLSE Please install a new version of LSE Error The version of the Language Sensitive Editor Source Code Analyzer on your system is too old for the compiler Contact your system manager INVCASERNG Invalid range in case label list Error INVEVAL Array or Record evaluation not allowed Error INVQUAVAL Value for optimizer level is out of range Default value will be used Error IVATTOPT Unrecognized option for attribute Explanation Explanation You attempted to specify an invalid option for one of the following attributes e CHECK Warning e FLOAT Warning e KEY Error e OPTIMIZE Warning IVATTR Unrecognized attribute Error IVAUTOMOD AUTOMATIC variable is illegal at the outermost level of a MODULE Error You cannot specify the AUTOMATIC attribute for a variable declared at module level IVCHKOPT Unrecognized CHECK option Warning Diagnostic Messages C 25 IVCOMBFLOAT Illegal combination of D floating and G floating Error You cannot combine D floating and G floating numbers in a binary operation IVDIRECTIVE Unrecognized directive Error The directive following a proc
246. modules from object module libraries Section 1 2 3 e On messages generated by the linker HP OpenVMS Linker Utility Manual e On DCL syntax HELP On the OpenVMS Linker HP OpenVMS Linker Utility Manual 1 2 2 LINK Qualifiers The following are command and file qualifiers that you can use when linking object modules NO DEBUG NODEBUG default Indicates that the VMS Debugger is to be included in the executable image and that a symbol table is to be generated If you specify LINK DEBUG the program links and then executes under the control of the debugger Compiling HP Pascal Programs 1 33 NOJEXECUTABLE EXECUTABLE default Produces an executable image A file specification can follow EXECUTABLE to designate a name for the image file The NOEXECUTABLE qualifier which suppresses production of the image file is useful when you want to verify the results of linking an object file before the image is produced INCLUDE none default Specifies that the input file is an object module or a shareable image library and that the modules named are the only ones in the library to be explicitly included as input In the case of shareable image libraries the module is the shareable image name You must specify at least one module name with the INCLUDE qualifier The default for library modules is the OLB file type This qualifier is a file qualifier and cannot be used directly on the LINK command LIBRARY none default
247. must first convert the higher ranked expression by using DBLE SNGL TRUNC ROUND UTRUNC or UROUND as appropriate EXPNOTRES Expression does not contribute to result Information The optimizer has determined that part of the expression does not affect the result of the expression and it will not evaluate that part of the expression EXPR2ONVAL Expression is allowed only on real integer or unsigned values Error The second expression and preceding colon are allowed only if the value being written is of a real integer or unsigned type EXPRARITH Expression must be arithmetic Error An expression whose type is not arithmetic cannot be assigned to a variable of a real type C 18 Diagnostic Messages EXPRARRIDX Expression is incompatible with unpacked array s index type Error The index type of the unpacked array is not compatible with the index type of either the PACK or UNPACK procedure it was passed to EXPRCOMTAG Expression is not compatible with tag type Error A case label specified for a NEW DISPOSE or SIZE routine must be assignment compatible with the tag type of the variant EXPRINFUNC Expression allowed only in FUNCTION Error EXPRNOTSET Expression is not a SET type Error The compiler encountered an expression of some type other than SET in a call to the CARD function EXTRNALLOC Allocation attribute conflicts with EXTERNAL visibility Error The storage for an external variable or routine is not
248. n unambiguous value User Action Specify enough characters of the identifier so that it is not ambiguous ARRINDVAL array index value is out of range Explanation You enabled bounds checking for a compilation unit and attempted to specify an index that is outside the array s index bounds User Action Correct the program or data so that all references to array indexes are within the declared bounds ARRNOTCOM conformant array is not compatible Explanation You attempted to assign one dynamic array to another that did not have the same index bounds This error occurs only when the arrays use the decommitted VAX Pascal Version 1 0 syntax for dynamic array parameters User Action Correct the program so that the two dynamic arrays have the same index bounds You could also change the arrays to conform to the current syntax for conformant arrays most incompatibilities could then be detected at compile time rather than at run time See the HP Pascal for OpenVMS Language Reference Manual for more information on current conformant arrays ARRNOTSTR conformant array is not a string Explanation In a string operation you used a conformant PACKED ARRAY OF CHAR value whose index had a lower bound not equal to 1 or an upper bound greater than 65535 User Action Correct the array s index so that the array is a character string C 66 Diagnostic Messages ASSERTION Pascal assertion failure Explanation The expression used in the
249. n a context where the compiler expected a type identifier NOTAVAR symbol name is not declared as a variable Error You cannot assign a value to any object other than a variable NOTAVARFNID symbol name is not declared as a variable or a function identifier Error You cannot assign a value to any object other than a variable or a function identifier NOTAVARPARM symbol name is not declared as a variable or parameter Error C 34 Diagnostic Messages NOTBEADDR May not be parameter to ADDRESS NOTBEARGYV May not be used as a parameter to ARGV NOTBEASSIGN May not be assigned NOTBECALL May not be called as FUNCTION NOTBECAST May not be type cast NOTBEDEREF May not be dereferenced NOTBEDES May not be passed by untyped DESCR NOTBEEVAL May not be evaluated NOTBEFILOP May not be used in a file operation NOTBEFLD May not be field selected NOTBEFNCPRM May not be passed as a FUNCTION parameter NOTBEFORCTL May not be used as FOR loop variable NOTBEFORDES May not be passed as a descriptor foreign parameter NOTBEFOREF May not be passed as a reference foreign parameter NOTBEIADDR May not be parameter to IADDRESS NOTBEIDX May not be indexed NOTBEIMMED May not be passed by untyped immediate passing mechanism NOTBENEW May not be written into by NEW NOTBENSTCTL May not be control variable for an inner FOR loop NOTBEREAD May not be written into by READ VOTBEREF May not be passed by untyped referen
250. n of user defined NOINLINE routines LEVEL num UNROLL num TUNE processor Controls the optimization level OpenVMS 164 and OpenVMS Alpha systems only Values for num are 0 Disables all optimizations Identical in function to NOOPTIMIZE 1 Enables local optimizations and recognition of common subexpressions 2 Enables all level 1 optimizations and some global optimizations including the following code motion strength reduction and test replacement split lifetime analysis and code scheduling 3 Enables all level 2 optimizations and some additional global optimizations that improve speed at the cost of extra code size These optimizations include integer multiplication and division expansion using shifts loop unrolling and code replication to eliminate branches Identical in function to OPTIMIZE NOINLINE 4 Enables all level 3 optimizations and inline expansion of procedures and functions Identical in function to OPTIMIZE 5 Enables software pipelining and additional software dependancy analysis which in certain cases improves run time performance Controls number of times loops are unrolled The default is 4 UNROLL 0 disables loop unrolling Loop unrolling is only enabled above optimzation level 2 OpenVMS I64 and OpenVMS Alpha systems only Tune the object code to run best on the processor chosen The default is Generic Values for the processor are EV4 EV5 EV56 EV6 EV7 EV67 EV68 G
251. n the variant part of record Table 4 2 lists valid contexts within an HP Pascal executable section where you can insert placeholders Table 4 2 Placeholders Within the Executable Section Can Replace Cannot Replace Statement LABEL identifier Variable TO DOWNTO within a FOR statement Expression Case label Complete case expression Iteration variable within a FOR statement HP Pascal support for placeholder and design comment processing includes the following language specific stipulations e Pseudocode placeholders are designated with double left and right angle brackets lt lt gt gt or the 8 bit format e The compiler produces an empty object file when it encounters pseudocode or LSE placeholders within a source program e Comment processing is limited to the declaration section 4 4 Programming Tools 4 2 3 LSE and SCA Examples Example 4 1 shows how you can use LSE tokens and placeholders to create a FOR statement within an HP Pascal program The callout numbers identify the steps in this process which are detailed in the notes appearing after the example Example 4 1 Using LSE to Create a FOR Statement BEGIN Q statement list END BEGIN For control var iteration clause DO amp statement amp statement list END BEGIN FOR INDEX 1 TO MAX DO e statement s statement_list END BEGIN FOR INDEX 1 TO MAX DO o t variable func_id
252. n the same block in which the FOR statement appears STDDECLSEC Nonstandard declaration sections either out of order or duplicated in block name Information In the Pascal standard the declaration sections must appear in the order LABEL CONST TYPE VAR PROCEDURE and FUNCTION The ability to specify the sections in any order is an extension This message occurs only if you have specified the standard switch on the compile command line STDDEFPARM Nonstandard default parameter declaration Information This message refers to extensions to Pascal and is issued only if you have specified the standard switch on the compile command line STDDIRECT Nonstandard directive name directive Information The EXTERN EXTERNAL FORTRAN and SEQ11 directives are extensions to Pascal FORWARD is the only directive specified by the Pascal standard This message is issued only if you have specified the standard switch on the compile command line STDDISCREF Nonstandard schema discriminant reference STDDISCSCHEMA Nonstandard discriminated schema Information These messages are issued if you have specified a standard argument other than extended on the compile command line STDEMPCASLST Nonstandard empty case list element Information This message is issued if you do not specify any case labels and executable statements between two semicolons or between OF and a semicolon in the CASE statement You must also have specified t
253. n time library routines require a variable number of parameters For example there is no fixed limit on the number of values that can be passed to functions that return the minimum or maximum value from a list of input parameters The LIST attribute supplied by HP Pascal allows you to indicate the mechanism by which excess actual parameters are to be passed For example ASYNCHRONOUS FUNCTION MTHSDMIN1 D FLOATING DOUBLE EXTRA PARAMS LIST DOUBLE DOUBLE EXTERNAL Because the function MTH DMINI1 returns the D floating minimum of an arbitrary number of D floating parameters the formal parameter EXTRA PARAMS is declared with the LIST attribute All actual parameters must be double precision real numbers passed by reference with value semantics For More Information On the LIST attribute HP Pascal for OpenVMS Language Reference Manual 6 12 Programming on OpenVMS Systems 6 3 Calling System Routines All system routines are functions that return an integer condition value this value indicates whether the function executed successfully An odd numbered condition value indicates successful completion an even numbered condition value indicates a warning message or failure Your program can use the HP Pascal predeclared function ODD to test the function return value for success or failure For example IF NOT ODD BINTIM Ascii Time Binary Time THEN BEGIN WRITELN Illegal format for time string HALT END In addit
254. nd TO END DO declarations in a module must appear at the end of the module and may not be reordered C 14 Diagnostic Messages DEFRTNPARM Default parameter syntax not allowed on routine parameters DEFVARPARM Default parameter syntax not allowed on VAR parameters Error DESCOMABORT Further processing of DESIGN COMMENTS has been aborted Error An error has occurred that prohibits further comment processing DESCOMERR An error has occurred while processing design information Error DESCOMSEVERR An internal error has occurred while processing DESIGN COMMENTS please submit an SPR Error A fatal error has occurred during comment processing Please submit a problem report including sufficient information to reproduce the program including the version numbers of the Language Sensitive Editor Source Code Analyzer and the HP Pascal compiler DESCTYPCON Descriptor class type conflict Error The descriptor class for parameter passing conflicts with the parameter s type Refer to Section 5 3 3 of the HP Pascal for OpenVMS User Manual for legal descriptor class type combinations DESIGNTOOOLD The comment processing routines are too old for the compiler Error The support routines for the DESIGN COMMENT qualifier are obsolete Contact your system manager DIRCONVISIB Directive contradicts visibility attribute Error The EXTERN EXTERNAL and FORTRAN directives conflict directly with the LOCAL and GLOBAL attributes
255. ne summary OpenVMS LIST SHOW INLINE VAX systems Compilation statistics LIST SHOW STATISTICS Structure layout LIST SHOW STRUCTURE_LAYOUT A compilation listing file usually contains source code because the SHOW SOURCE qualifier is enabled by default The LIST qualifier does not initiate the printing of the listing file To obtain a line printer copy of your listing file use the PRINT command You can control the number of lines that appear on a listing page by defining the SYS LP_LINES logical name before invoking the compiler For example DEFINE SYS LP LINES 100 PASCAL LIST DIR M This set of commands creates a printed page size of 94 lines the compiler subtracts six lines for margins The following sections describe the contents of each part of the listing file For More Information e On the PASCAL command qualifiers Section 1 1 2 e On the SYS LP_LINES logical HP OpenVMS Programming Concepts Manual 1 26 Compiling HP Pascal Programs 1 1 3 1 1 1 3 2 1 1 3 3 1 1 3 4 Table of Contents OpenVMS VAX systems The table of contents lists the line number listing page number and source file page number of each section of the source code These sections are delineated by TITLE or SUBTITLE directives that indicate the name by which the section is known for example Main Program Body The compiler ignores the SHOWZTABLE OF CONTENTS qualifier if the compilation unit does not contain a TITLE or SUB
256. ng to examine the LENGTH DBG EXAMINE WORD VARY STRING It should also be noted that the type cast operator is not permitted when evaluating HP Pascal expressions Pointers to undiscriminated schema cannot be correctly described to the debugger at this time since the type of the pointer is dependent upon the value pointed to by the pointer They are described as pointers to UNSIGNED integers For example TYPE S I INTEGER ARRAY 1 I OF INTEGER VAR P S BEGIN NEW P expression END 4 2 Language Sensitive Editor Source Code Analyzer Support for HP Pascal This section describes HP Pascal specific information for the following Language Sensitive Editor Source Code Analyzer LSE SCA features e Programming language placeholders and tokens e Placeholder processing e Design comment processing OpenVMS VAX systems 4 2 Programming Tools 4 2 1 Programming Language Placeholders and Tokens LSE accepts keywords or tokens for all languages with LSE support but the specific tokens themselves are language defined For example you can expand the 4 INCLUDE token only when using HP Pascal Likewise LSE provides placeholders or prompt markers for all languages with LSE support but the specific text or choices these markers call for are language defined For example you see the environ_name_string placeholder only when using HP Pascal Some HP Pascal keywords like TYPE VAR IF and FOR can be placeho
257. not new indexed files 4 12 Programming Tools Example 4 3 Using DICTIONARY to Access a Oracle CDD Repository Record Definition Program Show Keys OUTPUT TYPE SDICTIONARY Mail Order Info LIST VAR Old Customer File FILE OF Mail Order Order Rec Mail Order Continue BOOLEAN BEGIN OPEN File Variable Old Customer File File Name Customers Dat History OLD Organization Indexed Access Method Keyed FINDK Old Customer File 1 1000 NXTEQL Continue TRUE WHILE Continue and NOT UFB Old Customer File DO BEGIN READ Old Customer File Order Rec IF Order Rec Zip Code 5000 THEN WRITELN Order number Order Rec Order Num has zip code Order Rec Zip Code ELSE Continue False END END During the compilation of Show Keys the record definition Mail Order Info is extracted from the CDD Repository Show Keys prints the order number and zip code of each file component that has a zip code greater than or equal to 1000 but less than 5000 Programming Tools 4 13 5 Calling Conventions This chapter describes how HP Pascal passes parameters and calls routines It discusses the following topics Section 5 1 OpenVMS Calling Standard Section 5 2 Parameter Passing Semantics Section 5 3 Parameter Passing Mechanisms Section 5 4 Passing Parameters between HP Pascal and Other Languages For More Information On declaring and calling HP Pascal routines HP Pasca
258. ns In addition you cannot pass a predeclared routine as a parameter if there is no way to write the predeclared routine s formal parameter list in HP Pascal Examples of the latter case are the PRED and SUCC functions and many of the I O routines PASSEXTERN Passing mechanism allowed only on external routines Error PASSNOTLEG Passing mechanism not legal for this type Error PCKARRBOO PACKED ARRAY OF BOOLEAN parameter expected Error PCKUNPCKCON Packed unpacked conflict Information This message can appear as additional information on other error messages PLACEBEFEOLN Placeholder not terminated before end of line Error PLACEIVCHAR Illegal nonprinting character ASCII decimal representation of character within placeholder Warning PLACENODOT Repetition of pseudocode placeholders not allowed Error PLACESEEN Placeholder encountered Error PLACEUNMAT Unmatched placeholder delimiter Error POSAFTNONPOS Positional parameter cannot follow a nonpositional parameter Error Diagnostic Messages C 39 POSALIGNCON Position alignment conflict Error The bit position specified by the POS attribute does not have the number of low order bits implied by the specified alignment attribute POSINT POS expression must be a positive integer value Error PRENAMRED Predeclared name cannot be redefined Error A predeclared name may not be redefined when defining constants with the CONSTANT DCL qu
259. o exceed MAXINT bits Error The HP Pascal implementation restricts automatic storage to a size of 2 147 483 647 bits AUTOMAX Unable to quadword align automatic variables using long alignment Information BADANAORG Analysis data file file name is not on a random access device Fatal BADENVORG Environment file file name is not on a random access device Fatal BADSETCMB lt and gt not permitted in set comparisons Error BINOCTHEX Expecting BIN OCT or HEX Error You must supply BIN OCT or HEX as a variable modifier when reading the variable on a nondecimal basis BLKNOTFND routine block routine name declared FORWARD in block name is missing Error BLKTOODEEP Routine blocks nested too deeply Error You cannot nest more than 31 routine blocks C 6 Diagnostic Messages BNDACTDIFF Actual s array bounds differ from those of other parameters in same section Error All actual parameters passed to a formal parameter section whose type is a conformant schema must have identical bounds and be structurally compatible BNDCNFRUN Bounds of conformant ARRAY array name not known until run time Error You cannot use the UPPER and LOWER functions on a dynamic array parameter in a compile time constant expression BNDSUBORD Bound expressions in a subrange type must be ordinal Error The expressions that designate the upper and lower limits of a subrange must be of an ordinal type
260. o disjoint usage sections The value of v in the first section does not affect the value of v in the second section The compiler may use different registers for each section Code Scheduling OpenVMS 164 and OpenVMS Alpha systems Code scheduling is a technique for reordering machine instructions to maximize the amount of overlap of the multiple execution units inside the CPU The exact scheduling algorithms depend on the implementation of the target architecture Loop Unrolling OpenVMS 164 and OpenVMS Alpha systems Loop unrolling is a technique for increasing the amount of code between branch instructions and labels by replicating the body of a loop Increasing the code optimizes instruction scheduling The following code shows such a transformation Original Code FOR i 1 to 12 DO ali bli cli Unrolled Loop Code Bae I WHILE i lt 12 DO BEGIN ali b i c il a i 1 b i 1 c i 1 a i 2 b i 2 c i 2 a i 3 b i 3 c it 3 i 1 4 END In this example the loop body was replicated four times allowing the instruction scheduler to overlap the fetching of array elements with the addition of other array elements 3 10 Program Correctness Optimization and Efficiency 3 1 15 3 1 16 By default loop unrolling makes 4 copies of an unrolled loop You can change the number of copies from 1 to 16 This is controlled by OPTIMIZE UNROLL number Numbers larger than 4 may improve performance
261. ocess READLN Ascii Time continued on next page 6 4 Programming on OpenVMS Systems Example 6 1 Cont Inheriting STARLET PEN to Call SYSS HIBER Convert time to binary IF NOT ODD BINTIM Ascii Time Binary Time THEN BEGIN WRITELN Illegal format for time string HALT END Suspend process IF NOT ODD SUSPND PRCNAM Job Name THEN BEGIN WRITELN Cannot suspend process HALT END Schedule wakeup request for self IF ODD SSCHDWK DAYTIME Binary Time THEN SHIBER Put self to sleep ELSE BEGIN WRITELN Cannot schedule wakeup WRITELN Process will resume immediately END Resume process IF NOT ODD SRESUME PRCNAM Job Name THEN BEGIN WRITELN Cannot resume process HALT END END 6 2 Declaring System Routines Before calling a routine you must declare it System routine names conform to one of the two following conventions acility code procedure name For example LIBBPUT OUTPUT is the run time library routine used to write a record to the current output device and ASCTIM is a system service routine used to convert binary time to ASCII time Programming on OpenVMS Systems 6 5 Because system routines are often called from condition handlers or asynchronous trap AST routines you should declare system routines with the ASYNCHRONOUS attribute Each system routine is documented with a structured forma
262. ocess When a program opens a relative or indexed file and specifies SHARING READWRITE RMS locks each component as it is accessed When a component is locked any program that attempts to access it fails and a record locked error results A subsequent I O operation on the file variable unlocks the previously accessed component Thus at most one component is locked for each file variable If you use the READ procedure HP Pascal will implicitly unlock the component by executing the UNLOCK procedure during the execution of the READ procedure An HP Pascal program can explicitly unlock a component by executing the UNLOCK procedure To minimize the time during which a component is locked against access by other programs the UNLOCK procedure should be used in programs that retrieve components from a shared file but that do not attempt to update them HP Pascal requires that a component be locked before a DELETE or an UPDATE procedure can be executed Input and Output Processing 7 15 For More Information e Onthe OPEN UNLOCK DELETE and UPDATE procedures HP Pascal for OpenVMS Language Reference Manual 7 16 Input and Output Processing 8 Error Processing and Condition Handling This chapter discusses the following topics e Section 8 1 Condition Handling Terms e Section 8 2 Overview of Condition Handling e Section 8 3 Writing Condition Handlers e Section 8 4 Fault and Trap Handling OpenVMS VAX systems e Section 8 5 E
263. of the instructions However on Alpha and Itanium the architectures do not guarantee that independent writes will complete in the order in which they were issued Both architectures provide a special instruction to serialize write operations HP Pascal provides the BARRIER built in routine on these systems to generate the MB instruction on Alpha 3 20 Program Correctness Optimization and Efficiency systems and the mf instruction on Itanium systems in order to preserve write ordering If your code uses a higher level synchronization scheme to guard critical regions such as a lock manager or a semaphore package then using the VOLATILE attribute the GRANULARITY qualifier and the INTERLOCKED ATOMIC built ins may not be necessary you have already ensured that there are only single readers writers in the critical section 3 3 6 Debugging Considerations Some of the effects of optimized programs on debugging are as follows Use of registers When the compiler determines that the value of an expression does not change between two given occurrences it may save the value in a register In such a case it does not recompute the value for the next occurrence but assumes that the value saved in the register is valid If while debugging the program you attempt to change the value of the variable in the expression then the value of that variable is changed but the corresponding value stored in the register is not When execution continues
264. om OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha 9 7 9 7 5 Converting Existing Records When moving code from an OpenVMS VAX system to an OpenVMS I64 or OpenVMS Alpha system you probably want to make sure that you are getting the best performance on the new system To do that you must use natural alignment on your record types 9 7 6 Applications with No External Data Dependencies If your application has no external data dependencies such as no stored binary data files no binary data transmitted to some external device then the conversion is as simple as e Using the default natural alignment e Using the default enumeration size e Removing any uses of PACKED that are not needed e Removing any explicit positioning or size attributes that are not needed e Optionally reordering fields to place larger fields before smaller fields This does not make the record faster but does make it smaller Depending on your data types the removal of any PACKED keywords or attributes may make little improvement in performance For example a PACKED ARRAY OF REAL is identical in size and performance to an unpacked ARRAY OF REAL HP Pascal has two features to help you identify poorly aligned records and how often they are used e The USAGE PERFORMANCE command line option This option causes the compiler to generate messages for declarations and uses of record fields that are poorly aligned or poorly sized For example program a type r
265. on actual parameters 6 16 Routine activation definition of 8 2 RTL opening and closing a file 7 10 symbol definitions for 6 3 using LIST attribute with 6 12 RUN command 2 2 examples of 1 37 qualifier for 1 37 syntax of 1 37 Run time error detected by STATUS or STATUSV A 1 messages C 65 to C 86 Run time library See RTL S SAVE FILE command LSE 4 3 SCA example of use within program 4 5 to 4 8 support of HP Pascal 4 2 to 4 8 Schema type efficient use of nonstatic fields 3 15 of variant record example 2 12 Index 9 Semantics of parameter passing 5 6 5 15 variable with system services 6 9 Separate compilation 2 1 to 2 19 cascading inheritance figure 2 3 cascading interfaces figure 2 9 examples 2 16 interface inheritance path figure 2 7 multiply declared identifiers 2 4 relinking implementation modules 2 9 TO BEGIN DO section 2 12 SET type run time checking of 1 7 Shareable image 1 35 library 1 35 SHAREABLE qualifier with LINK command 1 35 Sharing of files 7 14 SHOW PLACEHOLDER command LSE 4 3 SHOW qualifier 1 19 SHOW TOKEN command LSE 4 3 SIGDEF PAS definition file 6 3 Signal definition of 8 2 Signal array 8 6 in condition handlers 8 6 Size attributes with data structure parameter 6 9 SIZE function used with item lists 6 16 Software pipelining 3 12 Source code in listing file 1 27 Source Code Analyzer See SCA Split lif
266. on handler for the routine activation A new routine activation is created every time a routine is called and is deleted when control passes from the routine Establish The process of placing the address of a condition handler in the stack frame of the current routine activation A condition handler established for a routine activation is automatically called when a condition occurs In HP Pascal condition handlers are established by means of the predeclared procedure ESTABLISH A routine that establishes a condition handler is known as an establisher Program exit status The status of the program at its completion Signal The means by which the occurrence of an exception condition is made known Signals are generated by the operating system in response to I O events and hardware errors by the system supplied library routines and by user routines All signals are initiated by a call to the signaling facility for which there are two entry points LIB SIGNAL Used to signal a condition and possibly to continue program execution LIB STOP Used to signal a severe error and discontinue program execution unless a condition handler performs an unwind operation Resignal The means by which a condition handler indicates that the signaling facility is to continue searching for a condition handler to process a previously signaled error To resignal a condition handler returns the value SS _RESIGNAL Unwind tThe return of c
267. on handling for 8 10 TRUNCATE attribute use with system routines 6 11 Type cast operator use with CDD Repository 4 10 use with debugger 4 2 Type conversion of constants 3 3 Type translations access 6 7 mechanism 6 7 U UNBOUND attribute 6 14 effect on routine call 5 6 Uninitialized variables types not checked 1 24 UNLOCK procedure 7 15 Unwind definition of 8 2 of stack by condition handler 8 7 UNWIND function called by condition handler 8 7 USAGE qualifier 1 22 User action function example of 7 11 parameters to 7 11 to open a file 7 10 V Variable effect on efficiency 3 15 initialization of 2 13 multiply declared identifiers 2 4 pointer 3 17 requirements for linking modules 2 2 types not checked for uninitialization 1 24 Variable semantics with system services 6 9 Variant record initial state specifiers for example 2 12 optimization considerations 3 18 VARYING OF CHAR type as function result type 5 3 used with LIB FIND FILE 6 17 Version information 1 25 VERSION qualifier 1 25 VMS programming using foreign mechanisms on actual parameters 6 16 using item lists 6 14 VOLATILE attribute 6 14 on pointer variables 3 17 Volatility 3 19 W Warning level error messages 1 25 effect of ERROR LIMIT 1 13 WARNINGS qualifier 1 25 WHILE statement effect on efficiency 3 14 WITH statement effect on efficiency 3 14 Write ordering 3 1
268. on on a file while EOF f was TRUE This situation occurs when a previous GET operation possibly implicitly performed by a RESET RESETK or READ procedure reads to the end of the file and causes the EOF f function to return TRUE If another GET is then performed this error is given User Action Correct the program so that it either tests whether EOF f is TRUE before attempting a GET operation or repositions the file before the end of file marker C 74 Diagnostic Messages GOTOFAILED non local GOTO failed Explanation An error occurred while a nonlocal GOTO statement was being executed This error might occur because of an error in the user program such as an out of bounds array reference User Action Rerun your program enabling all CHECK options If you cannot locate an error in your program and the problem persists please submit a Software Performance Report SPR to Hewlett Packard and include a machine readable copy of your program data and results of a sample execution showing the problem HALT HALT procedure called Explanation The program terminated its execution by executing the HALT procedure This message is solely informational User Action None ILLGOTO illegal uplevel GOTO during routine activation Explanation An uplevel GOTO was made into the body of a routine before the declaration part of the routine was completely processed User Action Correct the program to avoid the uplevel GOTO until the d
269. on the record for compatability with binary data files or when assuming that types like PACKED ARRAY OF BOOLEAN are implemented as bit strings While the compiler can position record fields at natural boundaries it cannot minimize the alignment bytes that are required between fields The calling standard requires the compiler to allocate record fields in the same lexical order that they appear in the source file For example type tl record fl char f2 integer f3 char f4 integer end The size of this record is 16 bytes e F1 is a byte field followed by 3 padding bytes to position F2 at a longword boundary e F2 is 4 bytes e F8 is a single byte followed by 3 more padding bytes to position F4 at a longword boundary e F4 is 4 bytes 9 6 Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha The optimal layout would be type t2 record f1 f2 integer f3 f4 char end The size of this record is only 12 bytes e FI and F2 are placed on adjacent longword boundaries e F3 and F4 can immediately follow since they can appear on any byte boundary they in turn are followed by 2 padding bytes to round the size of the record up to a multiple of its natural alignment of longword To achieve the fewest alignment bytes you should place larger fields at the beginning of the record and smaller fields at the end If you have record fields of schema types that have run time size you should place those at the v
270. ons enabled and recompile all modules using the same compiler If the problem persists please submit a Software Performance Report SPR to Hewlett Packard and include a machine readable copy of your program data and results of a sample execution showing the problem C 76 Diagnostic Messages INVKEYDEF invalid key definition Explanation Your program attempted to open a file of type RECORD whose component type contained a field with an invalid KEY attribute One of the following errors occurred e A new file was being created and the key numbers were not dense e A key field was defined at an offset of more than 65 535 bytes from the beginning of the record User Action If a new file is being created make sure that the key fields are numbered consecutively starting with 0 for the required primary key If you are opening an existing file you must explicitly specify HISTORY OLD or HISTORY READONLY as a parameter to the OPEN procedure Make sure that the length of the record is within the maximum permitted for the file organization being used See Chapter 7 for more information INVRADIX specified radix must be in the range 2 36 Explanation The specified radix for writing an ordinal value must be in the range of 2 through 36 User Action Modify the program to specify a radix in the proper range INVRECLEN invalid record length of nnn Explanation A file was being opened and one of the following errors occurred
271. ontrol to a particular routine activation bypassing any intermediate routine activations For example if X calls Y and Y calls Z and Z detects an error then a condition handler associated with X or Y can unwind to X bypassing Y Control returns to X immediately following the point at which X called Y 8 2 Error Processing and Condition Handling 8 2 Overview of Condition Handling When the OpenVMS system creates a user process a system defined condition handler is established in the absence of any user written condition handler The system defined handler processes errors that occur during execution of the user image Thus by default a run time error causes the system defined condition handler to print error messages and to terminate or continue execution of the image depending on the severity of the error When a condition is signaled the system searches for condition handlers to process the condition The system conducts the search for condition handlers by proceeding down the stack frame by frame until a condition handler is found that does not resignal The default handler calls the system s message output routine to send the appropriate message to the user Messages are sent to the SYS OUTPUT and SYS ERROR files If the condition is not a severe error program execution continues If the condition is a severe error the default handler forces program termination and the condition value becomes the program exit status You can c
272. or Constants cannot be made for nonstatic types since that would yield constants without compile time size and value SCHFLDALN Field in nonstatic type may not have greater than byte alignment Error SCHOVERLAID Use of schema types conflicts with OVERLAID attribute Error The OVERLAID attribute cannot be used on programs or modules that discriminate schema at the outermost level SENDSPR Internal Compiler Error Fatal An error has occurred in the execution of the HP Pascal compiler Along with this message you will receive information that helps you find the location in the source program and the name of the compilation phase at which the error occurred You may be able to rewrite the section of your program that caused the error and thus successfully compile the program However even if you are able to remedy the problem please submit a report to Hewlett Packard and provide a machine readable copy of the program SEQ11FORT PDP 11 specific directive SEQ11 treated as equivalent to FORTRAN directive Information SETBASCOM SET base types are not compatible Error The base type of two sets used in a set operation are not compatible SETELEORD SET element expression must be of an ordinal type Error The expressions used to denote the elements of a set constructor or the bounds of a set type definition must have an ordinal type SETNOTRNG SET element is not in range 0 255 Error In a set whose base type is a subrange of int
273. or so that it equals one of the case labels See the HP Pascal for OpenVMS Language Reference Manual for more information CONCATLEN string concatenation has more than 65535 characters Explanation The result of a string concatenation operation would result in a string longer than 65 535 characters which is the maximum length of a string User Action Correct the program so that all concatenations result in strings no longer than 65 535 characters Diagnostic Messages C 67 CSTRCOMISS invalid constructor component s missing Explanation The constructor did not specify sufficient component values to initialize a variable of the type User Action Specify more components in the constructor use the OTHERWISE clause in the constructor or modify the type definition to specify fewer components CURCOMUND current component is undefined for DELETE or UPDATE Explanation You attempted a DELETE or UPDATE procedure when no current component was defined A current component is defined by a successful GET FIND FINDK RESET or RESETK that locks the component Files opened with HISTORY READONLY never lock components User Action Correct the program so that a current component is defined before executing DELETE or UPDATE DELNOTALL DELETE is not allowed for a sequential organization file Explanation You attempted a DELETE procedure for a file with sequential organization which is not allowed DELETE is valid only on files with
274. osing block are correct Also controls whether the ASSERT statement is processed OVERFLOW Verifies that the result of an integer NOOVERFLOW computation does not exceed the machine representation POINTERS Verifies that the value of a pointer NOPOINTERS variable is not NIL SUBRANGE Verifies that values assigned to NOSUBRANGE variables of subrange types are within the subrange verifies that a set expression is assignment compatible with a set variable verifies that MOD operates on positive numbers The BOUNDS and DECLARATIONS options are the only checking options enabled by default The CHECK qualifier without options is equivalent to CHECK ALL The negation NOCHECK is equivalent to CHECK NONE The CHECK attribute in the source program or module overrides the CHECK qualifier on the command line CONSTANT name value The CONSTANT qualifier allows a limited set of Pascal constants to be defined from the command line This capability can be used to augment the conditional compilation facility name is the name of a Pascal constant to create You cannot define any predeclared Pascal name by the command line 1 8 Compiling HP Pascal Programs value can be one of the following e integer literal e integer literal e TRUE FALSE e string literal e string literal Nonbase 10 integer literals are not supported on the command line For example PASCAL CONSTANT DEBUG TRUE MAXSIZE 10 OFFSET
275. ot allowed Explanation Your program attempted to specify a negative value for the Digits argument in a call to the BIN HEX or OCT procedure which is not permitted User Action Correct the program so that only nonnegative Digits arguments are used for calls to BIN HEX and OCT NEGWIDDIG negative Width or Digits specification is not allowed Explanation A WRITE or WRITEV procedure on a text file contained a field width specification that included a negative Width or Digits value which is not permitted User Action Correct the program so that only nonnegative Width and Digits parameters are used NOTVALTY P string is not a value of type type Explanation Your program attempted a READ or READV procedure on a text file but the value read could not be expressed in the specified type For example this error results if a real value read is outside the range of the identifier s type or if an enumerated value is read that does not match any of the valid constant identifiers in its type User Action Correct the program or the input data so that the values read are compatible with the types of the identifiers receiving the data OPNDASSCOM operands are not assignment compatible Explanation The operands do not have the same type User Action Examine the declarations of the operands and make sure they have compatible types ORDVALOUT ordinal value is out of range Explanation A value of an ordinal type is outs
276. ou have specified the standard switch on the compile command line STDTAGFLD Nonstandard invalid use of tag field Information The tag field of a variant record cannot be a parameter to the ADDRESS function nor can you pass it as a writable VAR REF DESCR or STDESCR formal parameter This message is issued only if you have specified the standard switch on the compile command line STDTODECL Nonstandard TO BEGIN END DO declaration Information This message is issued if you have specified a standard argument other than extended on the compile command line STDUNSAFE Nonstandard UNSAFE compatibility Information If you have used the UNSAFE attribute on an object that is later tested for compatibility you will receive this message You must also have specified the standard switch on the compile command line STDUSEDCNF Nonstandard conformant array used as a string STDUSEDPCK Nonstandard PACKED ARRAY 1 1 OF CHAR used as a string Information These messages refer to extensions to Pascal and are issued only if you have specified the standard switch on the compile command line STDVALCNFPRM Nonstandard conformant array may not be passed to value conformant parameter Information STDVALUE Nonstandard VALUE initialization section STDVAXCDD Nonstandard DICTIONARY directive Information These messages refere to extensions to Pascal and are issued only if you have specified the standard switch on the compile comm
277. ou specified DEBUG to the linker while creating PROG EXE the image activator passes control to the debugger upon execution If you did not specify DEBUG to the linker while creating PROG EXE the image activator executes the program RUN NODEBUG PROG This example executes the image PROG EXE without invoking the debugger For More Information e On debugging Section 4 1 e On messages generated by the image activator Section 1 4 e On the DCL command RUN HP OpenVMS DCL Dictionary Compiling HP Pascal Programs 1 37 1 4 Error Messages During program development you can have to respond to messages regarding possible syntax or logic errors in your program These messages have the following form SOURCE CLASS MNEMONIC message text SOURCE A code that identifies the origin of the message For example the PASCAL code identifies the HP Pascal compiler and the PAS code identifies the HP Pascal run time system CLASS A single character that determines message severity The four classes of error messages are Informational I Warning W Error E and Fatal F The definition for each class depends on the source of the message but execution of your request does not continue when E or F level errors occur MNEMONIC A name that is unique to that message message text Explains the event that caused the message to be generated For example a common linker error occurs when you omit required file or library names
278. overlapped operations In this case software pipelining may not have enough registers available to effectively improve execution performance and using optimization level 5 instead of optimization level 4 may not improve run time performance To determine whether using optimization level 5 benefits your particular program time program execution for the same program compiled at level 4 and 5 For programs that contain loops that exhaust available registers longer execution times may result with optimization level 5 In cases where performance does not improve consider compiling using OPTIMIZE UNROLL 1 LEVEL 5 to possibly improve the effects of software pipelining 3 12 Program Correctness Optimization and Efficiency 3 1 18 3 1 19 Processor Selection and Tuning OpenVMS Alpha systems HP Pascal provides support for generating code for specific Alpha processors and for tuning code for a preferred processor The supported Alpha processors are EV4 EV5 EV56 EV6 EV7 EV67 and EV68 The EV4 and EV5 processors are basically identical with the only difference in the preferred instruction scheduling phase The EV56 processor added byte and word opcodes The EV6 processor added a SQRT instruction instructions to move data directly between floating and integer registers and a few other instructions The EV7 processor is similar to the EV6 processor with differences only in the instruction scheduling phase The default architectu
279. ovided with OpenVMS to convert the floating data Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha 9 13 A Errors Returned by STATUS and STATUSV Functions This appendix lists the error conditions detected by the STATUS and STATUSV functions their symbolic names and the corresponding values The symbolic names and their values are defined in the file SYS LIBRARY PASSTATUS PAS which you can include with a INCLUDE directive in a CONST section of your program To test for a specific condition you compare the STATUS or STATUSV return values against the value of a symbolic name The symbolic names correspond to some of the run time errors listed in Appendix C however not all run time errors can be detected by STATUS There is a one to one correspondence between the symbolic constants returned by STATUS or STATUSV documented in PASSTATUS PAS and the OpenVMS condition code values in SYS LIBRARY PASDEF PAS The following routine shows how to map the return value of STATUS to its corresponding condition code located in PASDEF PAS FUNCTION CONVERT STATUS TO CONDITION STAT INTEGER INTEGER BEGIN CONVERT STATUS TO CONDITION 1614218644 STAT 8 END Table A 1 lists the symbolic names and the values returned by the STATUS and STATUSV functions and explains the error condition that corresponds to each value Errors Returned by STATUS and STATUSV Functions A 1 Table A 1 STATUS and STATUSV Return Values Name
280. pecified the extended argument to the standard switch on the compile command line STDRADIX Nonstandard radix constant Information This message refers to the use of an extension to Pascal This message is issued only if you have specified a standard switch other than extended on the compile command line C 52 Diagnostic Messages STDRDBIN Nonstandard binary input from a TEXT file STDRDENUM Nonstandard enumerated type input from a TEXT file STDRDHEX Nonstandard hexadecimal input from a TEXT file STDRDOCT Nonstandard octal input from a TEXT file STDRDSTR Nonstandard string input from a TEXT file Information The Pascal standard allows only INTEGER CHAR and REAL values to be read from a text file The ability to read values of other types is an extension to Pascal These messages are issued only if you have specified the standard switch on the compile command line STDREDECLNIL Nonstandard redeclaration of reserved word NIL Information The Pascal standard considers NIL a reserved word while HP Pascal considers it to be a predeclared identifier Thus if you have specified the standard switch on the compile command line this message will be issued if you attempt to redefine NIL STDREM Nonstandard REM operator Information The item listed in this message is an extension to Pascal This message is issued only if you have specified the standard switch on the compile command line STDSCHEMA Nonstandard schema type
281. pected results may occur in the program now being compiled ENVOLDVER Environment was created by a VAX Pascal V2 compiler please recompile Warning The environment file inherited by the program was created by a VAX Pascal Version 2 0 compiler You should regenerate the environment file with a newer version of the compiler ENVWARN Environment resulted from a compilation with Warnings Warning The environment file inherited by the program compiled with warnings Unexpected results may occur in the program now being compiled ENVWRGCMP Environment identifier was compiled by an HP Pascal for platform compiler Fatal Diagnostic Messages C 17 ERREALCNST Error in real constant digit expected Error ERRNONPOS ERROR parameter can be specified only with nonpositional syntax Error ERROR 2ERROR Error This message is generated by the ERROR directive ERRORLIMIT Error Limit current error limit source analysis terminated Fatal The error limit specified for the program s compilation was exceeded the compiler was unable to continue processing the program By default the error limit is set at 30 but you can use the error limit switch at compile time to change it ESTBASYNCH ESTABLISH requires that routine name be ASYNCHRONOUS Warning EXPLCONVREQ Explicit conversion to lower type required Error An expression of a higher ranked type cannot be assigned to a variable of a lower ranked type you
282. perands if needed Note that the listing format is similar to but not exactly like MACRO That is if the section is edited to remove the hexadecimal notation on the left side it will not assemble using the Itanium assembler MACRO 64 assembler or the MACRO 32 assemblers for 164 or Alpha or VAX systems respectively Compiling HP Pascal Programs 1 27 1 1 3 5 Structured Layout Section This listing section gives the sizes record field offsets and comments about nonoptional performance for variables and types in your program This section is useful to aid in restructuring data types for optimal performance 1 1 3 6 Inline Summary OpenVMS VAX systems The inline summary part of a listing file contains a summary indicating which routine calls of user defined routines were or were not expanded inline This summary includes the name of the calling routine program or module the call and line number of the call and a notation indicating whether expansion occurred 1 1 3 7 Compilation Statistics The compilation statistics part of a listing file contains the following categories of summary information e Psect Summary listing the program section name number of bytes and attributes of all program sections created during compilation e Environment Statistics listing the names of all environment files inherited by the compilation and symbol information This information includes the total number of symbols in the environment fi
283. piler see the HP Pascal for OpenVMS Language Reference Manual for a checklist of language extensions not included in the Pascal standard The HP Pascal for OpenVMS Language Reference Manual also provides information on the Pascal standard Intended Audience This manual is intended for experienced applications programmers with a firm understanding of the Pascal language Some familiarity with the operating system is helpful Document Structure This manual contains the following chapters and appendixes e Chapter 1 provides information on compiling programs linking programs running programs and using text and object module libraries e Chapter 2 describes the use of separately compiled modules e Chapter 3 describes programming techniques that improve the efficiency of compilation and execution e Chapter 4 provides information on tools that you may want to use to develop HP Pascal programs e Chapter 5 provides information on the OpenVMS Calling Standard as applied to HP Pascal programs Xi Chapter 6 provides information on HP Pascal system definitions files and declaring and calling system routines Chapter 7 provides information on the relationship between HP Pascal input and output and the underlying OpenVMS VAX Record Management Services RMS constructs Chapter 8 provides information on error processing and writing condition handlers Chapter 9 provides information on migrating from OpenVMS to OpenVMS 164 or OpenVM
284. ple ASYNCHRONOUS FUNCTION LIBSGET FOREIGN VAR Resultant String CLASS S VOLATILE PACKED ARRAY 11 u1 INTEGER OF CHAR Prompt String CLASS S TRUNCATE PACKED ARRAY 12 u2 INTEGER OF CHAR IMM VAR Resultant Length VOLATILE TRUNCATE SUWORD I VAR Flags VOLATILE TRUNCATE UNSIGNED INTEGER EXTERNAL Programming on OpenVMS Systems 6 11 With this declaration it is possible to specify values for Resultant String and Prompt String and truncate the call list at that point In this case two parameters would be passed in the CALL instruction You may want to use a combination of the IMMED 0 and TRUNCATE methods This combination would allow you to skip the specification of intermediate optional parameters as well as allow you to truncate the call list once all desired parameters have been specified Note that OpenVMS system services require a value to be passed by parameters including optional parameters therefore you should not use the TRUNCATE attribute when defining optional parameters to a system service Instead you should specify default values on the formal parameter declaration The TRUNCATE attribute is useful when calling routines for which the optional parameter is truly optional for example when calling run time library routines For More Information e On the TRUNCATE attribute HP Pascal for OpenVMS Language Reference Manual 6 2 6 Arbitrary Length Parameter Lists Some ru
285. presentation for the type Similarly you cannot read a value from a text file using READ or READLN or from a VARYING string using READV if there is no textual representation for the type The only legal array therefore is PACKED ARRAY 1 n OF CHAR ASYREQASY ASYNCHRONOUS calling routine requires that called routine also be ASYNCHRONOUS Warning ASYREQVOL ASYNCHRONOUS routine name requires that variable name be VOLATILE Warning A variable referred to in a nested asynchronous routine must have the VOLATILE attribute ATINTUNS AT address must be an integer value Error ATREXTERN attribute name attribute allowed only on external routines Error The LIST and CLASS_S attributes can be specified only with the declarations of external routines Diagnostic Messages C 5 ATTRCONCMDLNE Attribute contradicts command line qualifier Error The double precision attribute specified contradicts the FLOAT G FLOATING or NOG FLOATING qualifier specified on the compile command line ATTRCONFLICT Attribute conflict attribute name Information This message can appear as additional information on other error messages ATTRONTYP Descriptor class attribute not allowed on this type Error The use of the descriptor class attribute on the variable parameter or routine conflicts with the requirements of the object s type AUTOGTRMAXINT Allocation of variable name causes automatic storage t
286. product and do not contain symbol definitions for subsequent releases of the product For definitions that are complete for the latest release of OpenVMS use the individual PASCAL files or STARLET To access these files use the INCLUDE directive in the CONST declaration section of your program continued on next page Programming on OpenVMS Systems 6 3 Table 6 1 Cont HP Pascal Definitions Files File Description HP Pascal Run Time Library Files PASSTATUS PAS Contains definitions for all values returned by the STATUS and STATUSY routines For instance the external routine declarations in STARLET define new identifiers by which you can refer to the routines Example 6 1 shows that you can refer to SYS HIBER as HIBER if you use STARLET Example 6 1 Inheriting STARLET PEN to Call SYS HIBER INHERIT SYSSLIBRARY STARLET PROGRAM Suspend INPUT OUTPUT TYPE Sys Time RECORD I J INTEGER END Unsigned Word WORD 0 65535 VAR Current Time PACKED ARRAY 1 80 OF CHAR Length Unsigned Word Job Name VARYING 15 OF CHAR Ascii Time VARYING 80 OF CHAR Binary Time Sys Time BEGIN Print current date and time SASCTIM TIMLEN Length TIMBUF Current Time WRITELN The current time is SUBSTR Current Time 1 Length Get name of process to suspend WRITE Enter name of process to suspend READLN Job Name Get time to wake process WRITE Enter time to wake pr
287. pulated with the MOVCS3 MOVCS instructions are not atomic as those instructions may be interrupted Besides atomic accesses many programs want to perform atomic operations on shared data To facilitate this HP Pascal provides the following built in routines e ADD INTERLOCKED expr variable This routine adds the expression to the aligned word variable and returns 1 if the new value is negative 0 if it is zero or 1 if it is positive On OpenVMS 164 systems it uses the cmpxchg instruction On OpenVMS Alpha systems it uses the LDx L STx C instructions On OpenVMS VAX systems it generates the VAX ADAWI instruction e CLEAR INTERLOCKED Boolean variable SET INTERLOCKED Boolean variable These routines clear or set a Boolean variable respectively and return the original value On OpenVMS I64 systems they use the cmpxchg instruction On OpenVMS Alpha systems they use the LDx L STx C instructions On OpenVMS VAX systems they generate the BBCCI and BBSSI instructions respectively e ADD ATOMIC expr variable AND ATOMIC expr variable OR ATOMIC expr variable These routines atomically add and or the value of the expression with the variable and return the original value On OpenVMS I64 systems they use the cmpxchg instruction On OpenVMS Alpha systems they use the LDx L STx C instructions These routines are not on OpenVMS VAX systems On the VAX write operations to independent memory locations are completed in the order
288. quired it consists of a fixed part which is known at compile time and an optional variable part The compiler determines the exact contents of the stack frame but all stack frames have common characteristics Fixed temporary locations This is an optional section that contains language specific locations required by the procedure context of some languages Register save area This is a set of consecutive quadwords for storing registers saved and restored by the current procedure Argument home area If allocated this is a region of memory used by the called process to assemble the arguments passed in registers adjacent to the arguments passed in memory This allows all arguments to be addressed as a contiguous array The argument home area is also used to store arguments passed in registers if an address for such an argument is required Arguments passed in memory On OpenVMS VAX Systems Each time a routine is called by an HP Pascal program on an OpenVMS VAX system the hardware creates a call frame structure on the call stack The call frame for each active routine contains the following A pointer to the call frame of the previous routine call This pointer is called the saved frame pointer FP The saved argument pointer AP of the previous routine call The storage address of the point at which the routine was called that is the address of the instruction following the call to the current routine This address is called t
289. r Class and Type CLASS A CLASS NCA CLASS S ARRAY OF VARYING OF CHAR Conformant ARRAY Conformant ARRAY OF VARYING OF CHAR VARYING OF CHAR Conformant VARYING OF CHAR STRING Schema name Discriminated schema SET FILE Pointer PROCEDURE or FUNCTION DSC K CLASS A DSC K CLASS NCA DSC K CLASS S DSC K DTYPE T DSC K CLASS S DSC K DTYPE Z DSC K CLASS S DSC K DTYPE Z DSC K CLASS S DSC K DTYPE LU Descriptor s D type depends on component type 3O0nly if PACKED ARRAY OF CHAR 4Component type can be a conformant VARYING OF CHAR 5 12 Calling Conventions 5 3 3 1 CLASS S Attribute When the CLASS S attribute is used on a formal parameter the compiler generates a fixed length scalar descriptor of a variable and passes its address to the called routine Only ordinal real set pointer and one dimensional packed arrays fixed or conformant that are of type OF CHAR can have the CLASS S attribute on the formal parameter With the CLASS S attribute the type of passing semantics used for the by descriptor argument depends on the use of the VAR keyword If the formal parameter name is preceded by the reserved word VAR variable semantics is used otherwise value semantics is used 5 3 3 2 CLASS A and CLASS NCA Attributes When you use the CLASS A or CLASS NCA attribute on a formal parameter the compiler generates an array descriptor and passes its address to the call
290. r More Information e On the OpenVMS Run Time Library HP OpenVMS Programming Concepts Manual B 3 PASSMARK s The PAS MARK2 function returns a pointer to a heap allocated object of the size specified by s If this pointer value is then passed to the PAS RELEASE2 function all objects allocated with NEW or PAS MARKQ2 since the object was allocated are deallocated PAS MARK2 and PAS RELEASE2 are provided only for compatibility with some other implementations of HP Pascal Their use is not recommended in a modular programming environment The PAS MARK2 and PAS RELEASE2 routines do not work with 64 bit pointers on OpenVMS I64 and OpenVMS Alpha While a mark is in effect any DISPOSE operation will not actually delete the storage but merely mark the storage for deletion To free the memory you must use PAS RELEASE2 B 2 Entry Points to HP Pascal Utilities PAS MARK2 is an external function that must be explicitly declared Because the parameter to PAS MARKQ2 is the size of the object unlike the parameter to the predeclared procedure NEW the best method for using this function is to declare a separate function name for each object you wish to mark The following example shows how PAS MARK2 could be declared and used as a function named Mark Integer to allocate and mark an integer variable TYPE Ptr to Integer Integer VAR Marked Integer Ptr to Integer EXTERNAL PASSMARK2 FUNCTION Mark Integer SIMMED S Integer SIZE
291. rated code This handler in the RTL in turn calls the user condition handler that was established with the ESTABLISH built in routine The RTL handler contains a check to prevent a user handler from returning SS CONTINUE for a certain class of Pascal Run Time Errors that could cause an infinite loop if execution was to continue at the point of the error There are two situations in which this check may cause unexpected behavior e The user handler called UNWIND and then returned with SS CONTINUE Because the UNWIND service was called execution will not resume at the point of the error even if SS CONTINUE is returned to the system However the RTL handler is not aware that UNWIND has been called and will report that program operation cannot continue for this type of error The solution is to return SS RESIGNAL instead of SS CONTINUE after calling UNWIND in the user handler However this solution is not possible if you establish the LIB SIG TO RET routine with the ESTABLISH built in routine LIB SIG TO RET is a routine that can be used as a condition handler to convert a signal into a return to the caller of the routine that established LIB SIG TO RET Because LIB SIG TO RET returns SS NORMAL which in turn is the same value as S8 CONTINUE the handler in the Pascal RTL will report that program operation cannot continue for this type of error The solution for this case is to establish your own handler with the ESTABLISH built
292. ray parameter a conformant VARYING parameter or a VARYING OF CHAR expression The target type of the cast cannot be VARYING OF CHAR CDDABORT DICTIONARY processing of CDD record definition aborted Error The HP Pascal compiler is unable to process the CDD record description See the accompanying CDD messages for more information CDDBADDIR DICTIONARY directive not allowed in deepest INCLUDE ignored Error A program cannot use the 7DICTIONARY directive in the fifth nested INCLUDE level The compiler ignores all DICTIONARY directives in the fifth nested 7INCLUDE level CDDBADPTR invalid pointer was specified in CDD record description Warning The CDD pointer data type refers to a CDD path name that cannot be extracted and is replaced by INTEGER CDDBIT Ignoring bit field in CDD record description Information The HP Pascal compiler cannot translate a CDD bit data type that is not aligned on a byte boundary and whose size is greater than 32 bits CDDBLNKZERO Ignoring blank when zero attribute specified in CDD record description Information The HP Pascal compiler does not support the CDD BLANK WHEN ZERO clause CDDCOLMAJOR CDD description specifies a column major array Error The HP Pascal compiler supports only row major arrays Change the CDD description to specify a row major array C 8 Diagnostic Messages CDDDEPITEM Ignoring depends item attribute specified in CDD record description Information The HP
293. re HP Pascal for OpenVMS Language Reference Manual Input and Output Processing 7 1 6 2 OPEN and RMS Data Structures Table 7 2 presents the status of RMS FAB fields when you call the OPEN procedure If a field is not included in the following tables it is initialized to zero Table 7 2 Setting of RMS File Access Block Fields by a Call to the OPEN Procedure Field Name OPEN Parameters and Value FAB L_CTX Context Reserved to Hewlett Packard FAB L_DEV Device characteristics Returned by RMS FAB L_DNA Default file specification DEFAULT parameter value if specified string address else DAT FAB L_DNS Default file specification Set to length of default file name string string size FAB B_FAC File access options FAB V_DEL Allow deletions 1 if not HISTORY READONLY FAB V_GET Allow reads 1 FAB V_PUT Allow writes 1 if not HISTORY READONLY FAB V_TRN Allow truncations 1 if not HISTORY READONLY FAB V_UPD Allow updates 1 if not HISTORY READONLY FAB L_FNA File specification string FILE_NAME if specified name of file address variable if external file else 0 FAB B_FNS File specification string Set to length of file name string size FAB L_FOP File processing options FAB V CIF Create if nonexistent 1 if HISTORY UNKNOWN FAB V_DFW Deferred write 1 FAB V_DLT Delete on close service Set when file is closed depends on DISPOSITION FAB V_NAM Name block inputs 1 if terminal file reopened to enable prompting FAB V_SFC Submi
294. re see the ARCHITECTURE qualifier is for the EV4 processor This restricts the compiler to instructions that exist on the EV4 processor It essentially tells the compiler the earliest Alpha processor that will execute the code If you run the code on earlier Alpha systems you might get invalid opcode errors or OpenVMS might attempt to emulate the instructions at a severe performance penalty The default tuning see the OPTIMIZE TUNE qualifier is generic The tuning is for an average Alpha processor You can achieve better performance it you allow the compiler to tune the code for a specific processor Specifying an explicit ARCHITECTURE setting also defaults the OPTIMIZE TUNE setting to the same processor For example specifying ARCHITECTURE EV56 OPTIMIZE TUNE EV7 tells the compiler to use instructions that the generated code should be able to run on an EV56 system but that it should tune the generated code for best performance on an EV system In these situations the compiler can actually generate multiple code sequences one using only EV56 instructions and the other using EV7 instructions and the AMASK instruction to dynamically execute the faster sequence based on the system executing the program Since most Alpha systems are EV56 or later you might see a significant improvement by specifying ARCHITECTURE EV56 on the command line Compiling for Optimal Performance The following command lines will result in producing t
295. reate and establish your own condition handlers according to the needs of your application For example a condition handler could create and display messages that describe specific conditions encountered during the execution of your program instead of relying on system error messages 8 2 1 Condition Signals A condition signal consists of a call to either LIB SIGNAL or LIB STOP the two entry points to the signaling facility These entry points can be inherited from SYS LIBRARY PASCAL LIB ROUTINES PEN If a condition occurs in a routine that is not prepared to handle it a signal is issued to notify other active routines If the current routine can continue after the signal is propagated you can call LIB SIGNAL A higher level routine can then determine whether program execution should continue If the nature of the condition does not allow the current routine to continue you can call LIB STOP 8 2 2 Handler Responses A condition handler responds to an exception condition by taking action in three major areas e Condition correction e Condition reporting e Execution control Error Processing and Condition Handling 8 3 The handler first determines whether the condition can be corrected If so it takes the appropriate action and execution continues If the handler cannot correct the condition the condition may be resignaled that is the handler requests that another condition handler be sought to process the condition A handler
296. refore preserve no context of its caller However unlike an OpenVMS Alpha null frame procedure these procedures do not execute in the context of its caller On OpenVMS 164 systems the compiler determines the exact contents of the memory stack frame but all memory stack frames have common characteristics e Scratch area A 16 byte region is provided as scratch storage for procedures that are called by the current procedure Leaf procedures need not allocate this area A procedure can use the 16 bytes pointed to by the stack pointer as scratch memory but the contents of this area are not preserved by a procedure call e Arguments passed in memory Parameters beyond those passed in registers are stored in this area of the memory stack frame A procedure accesses its incoming parameters in the outgoing parameter area of its caller s memory stack frame e Local storage A procedure can store local variables temporaries and spilled registers in this area There are specific conventions that affect the layout for spilled registers 5 4 Calling Conventions On OpenVMS Alpha Systems On OpenVMS Alpha systems the types of procedures are Stack frame procedures in which the calling context is placed on the stack Register frame procedures in which the calling context is in registers No frame procedures for which the compiler does not establish a context and which therefore execute in the context of the caller If a stack frame is re
297. ribe where the service should place its output These item lists can have an arbitrary number of cells and are terminated with a longword of value 0 Since different programs need a different number of item list cells you can use a schema type to define a generic item list data type This schema type can then be discriminated with the appropriate number of cells Consider the following example 6 14 Programming on OpenVMS Systems TYPE Item List Cell RECORD CASE INTEGER OF vid Normal Cell Buffer Length WORD 0 65535 Item Code WORD 0 65535 Buffer Addr UNSIGNED Return Addr UNSIGNED i 2 Terminator Terminator UNSIGNED END Item List Template Count INTEGER ARRAY 1 Count OF Item List Cell The Item List Cell data type specifies what a single cell looks like The Buffer Addr and Return Addr fields are declared as UNSIGNED since most applications use the IADDRESS predeclared routine to fill them in The Item List Template schema type defines an array of item list cells with a upper bound to be filled in by an actual discriminant To use this schema type first determine the number of item list cells required including one cell for the terminator After the number of cells has been determined declare a variable discriminating the schema Consider the following example VAR Item List Item List Template 2 Additionally since actual discriminants to schema can be run time expres
298. ring OPEN Explanation An unexpected error occurred during execution of the OPEN procedure or during an implicit open caused by a RESET or REWRITE procedure An additional message is displayed that further describes the error User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the additional message ERRDURPRO error during prompting Explanation RMS reported an unexpected error during output of partial lines to a terminal The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the RMS error ERRDURPUT error during PUT Explanation RMS reported an unexpected error during execution of the PUT procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the RMS message ERRDURREL error during RELEASE Explanation An unexpected error occurred during execution of the PAS RELEASE2 procedure An additional message may be displayed that further describes the error User Action Make sure that the marker argument was returned from a successful call to PAS MARK2 and that the storage has not been already freed If an additional message is displayed see the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of that message ERRDURRES error during RESET or RES
299. rs enclosed in parentheses can follow DEBUG these identifiers are the names of options that inform the compiler which type of information it should generate Table 1 4 lists the available options their corresponding actions and their negations 1 10 Compiling HP Pascal Programs Table 1 4 DEBUG Qualifier Options Option Action Negation ALL Specifies that the compiler should NONE include symbol and traceback information in the object module SYMBOLS Specifies that the compiler should NOSYMBOLS include in the object module symbol definitions for all identifiers in the compilation TRACEBACK Specifies that the compiler should NOTRACEBACK include in the object module traceback information permitting virtual addresses to be translated into source program routine names and compiler generated line numbers When debugging programs that contain schema you must use the NOOPTIMIZE qualifier on the PASCAL DCL command If you do not use NOOPTIMIZE you might receive incorrect debug information or an Internal Debug Error when manipulating schema When you specify SYMBOLS without TRACEBACK the table of compiler generated line numbers is omitted from the debugger symbol table You should consider using NOOPTIMIZE when you are using DEBUG Allowing optimizations to occur can make debugging difficult and can obscure some sections of the compilation unit The DEBUG qualifier without options is equivalent to DE
300. rying length string descriptor as its parameter TYPE Vary VARYING 30 OF CHAR VAR Obj String Vary Times Found INTEGER EXTERNAL FUNCTION Search String DESCR String Val Vary BOOLEAN EXTERNAL 5 14 Calling Conventions IF Search String Obj String THEN Times Found Times Found 1 The actual parameter Obj String is passed by varying string descriptor with variable semantics to the formal parameter String Val For More Information e On descriptor classes and types HP OpenVMS Calling Standard 5 3 4 Summary of Passing Mechanisms and Passing Semantics Table 5 4 summarizes the passing semantics used when various mechanisms are specified on either the formal or the actual parameter For example if a variable is passed to a formal parameter that was declared without the keyword VAR and either REF or REFERENCE was specified then variable passing semantics will be used Likewise if a variable is passed to a formal parameter which was declared with the keyword VAR and either REF or REFERENCE was specified then an error will occur If an actual parameter is preceded by an IMMED specifier regardless of what passing mechanism is used to declare the formal parameter foreign semantics would be used because a specifier appearing on the actual parameter always overrides the semantics specified on the formal parameter Calling Conventions 5 15 Table 5 4 Summary of Passing Mechanisms and Passing Sem
301. s single identifier or a list of identifiers enclosed in parentheses can follow USAGE these identifiers are options that tell the compiler which checks to perform Table 1 13 lists the available options their corresponding actions and their negations Table 1 13 USAGE Qualifier Options Option Action Negation ALL Enables checking of all options NONE EMPTY RECORDS Checks for fetching records NOEMPTY RECORDS with no fields Such fields are usually created by the DICTIONARY directive for unsupported data types continued on next page 1 22 Compiling HP Pascal Programs Table 1 13 Cont USAGE Qualifier Options Option Action Negation NONGRNACC OpenVMS I64 and OpenVMS Alpha systems PACKED ACTUALS PERFORMANCE OpenVMS I64 and OpenVMS Alpha systems UNCALLABLE OpenVMS I64 and OpenVMS Alpha systems Specifies that the compiler should issue warning messages for code sequences that might not match your granularity request from the GRANULARITY qualifier When the compiler cannot guarantee that the generated code matches the granularity setting a warning message is issued You should examine your code to make sure that the variable being accessed is quadword aligned and is a multiple of quadwords in size In this case the resulting code will be correct although the compiler might not be able to determine that at compile time Such cases involve pointer dereferences or VAR
302. s Coordinate X Coordinate Y REAL VALUE 50 0 CASE t OF Shape specific values Rectangle Height Width REAL VALUE 10 0 Circle Radius REAL VALUE 5 0 END Provide routines that manipulate the shapes PROCEDURE Draw s Shape EXTERNAL PROCEDURE Rotate s Shape EXTERNAL PROCEDURE Scale s Shape EXTERNAL PROCEDURE Delete s Shape EXTERNAL The interface module provides an interface to the rest of the application This module contains types and external procedure declarations that the data model chooses to make available to other compilation units in the application other units can access these types and routines by inheriting the generated environment file 2 12 Separate Compilation The type Shape Types defines two legal graphical objects for this application a circle and a rectangle The type Shape can be used by other units to create circles and rectangles of specified dimensions This code uses a variant record to specify the different kinds of data needed for a circle a radius value and a rectangle height and width values Since the type has initial state values any variable declared to be of this type receives these values upon declaration Providing initial states for types that are included in environment files can prevent errors when other compilation units try to access uninitialized data The initial states in this code are specified for the individual record values Yo
303. s and uses variable semantics to manipulate the parameter within the service Because you can call BINTIM from a condition handler or AST routine you should declare it with the ASYNCHRONOUS attribute Also because you may want to pass a volatile variable to the TIMADR parameter you should use the VOLATILE attribute to indicate that the argument is allowed to be volatile 6 2 4 Data Structure Parameters Some system services require a parameter to be the address of a data structure that indicates a function to be performed or that holds information to be returned Such a structure can be described as a list a control block or a vector The size and POS attributes provide an efficient method of laying out these data structures The size attributes ensure that the fields of the data structure are of the size required by the system service and the POS attribute allows you to position the fields correctly Programming on OpenVMS Systems 6 9 For example the Get Job Process Information SYS GETJPIW system service requires an item list consisting of an array of records of 12 bytes where all but the last array cell requests one piece of data and the last array cell represents the item list terminator By packing the record you can guarantee that the fields of each record are allocated contiguously Example 6 2 uses the system service routine GETJPIW to retrieve the process s name as a 12 byte string Example 6 2 Using SGETJPIW to Retrieve a
304. s include byte and word instructions See the ARCHITECTURE qualifier for more information Only aligned data objects are guaranteed to be accessed atomically Larger objects that are manipulated with run time routines are not atomic as those routines may be interrupted Granularity is a term on Alpha machines to describe the situation where two threads update nearby data at the same time Because the compiler on the older Alpha must fetch the surrounding longword or quadword modify it and store it back the two threads could possibly overwrite each others data For these situations the nearby data should be moved to separate quadwords or use the GRANULARITY qualifier to tell the compiler that you want longword or byte granularity at the expense of additional LDx L STx C sequences See the ARCHITECTURE qualifier for more information on the byte and word instructions available on newer Alpha systems Program Correctness Optimization and Efficiency 3 19 To accomplish atomic access on the VAX for volatile objects 32 bits or smaller fetches and stores are done with the normal MOVB MOVW MOVL INSV EXTV instructions In a single CPU environment the alignment of the objects is not relevant However in a multiple CPU SMP system the data being accessed must reside in a single 32 bit longword otherwise the underlying memory system may return incorrect data if two CPUs are updating the same longwords at the same time Larger objects that are mani
305. s must be dense that is you may not omit any key numbers in the range from 0 through the highest key number specified for the file s component type IDXREQKEYO Creating INDEXED organization requires FILE OF RECORD with at least KEY 0 Warning When you specify ORGANIZATION INDEXED when opening a file with HISTORY NEW or UNKNOWN the file s component type must be a record for which a primary key designated by the KEY 0 attribute is defined ILLINISCH Illegal initialization of variable of nonstatic type Error Nonstatic variables such as those created from schema types cannot be initialized in the VALUE declaration part To initialize these variables you must use the initial state feature IMMEDBNDROU Immediate passing mechanism may not be used on bound routine routine name Warning You cannot prefix a formal or an actual routine parameter with the immediate passing mechanism unless the routine was declared with the UNBOUND attribute IMMEDUNBND Routines passed by immediate passing mechanism must be UNBOUND Warning A formal routine parameter that has the immediate passing mechanism must also have the UNBOUND attribute IMMGTR32 Immediate passing mechanism not allowed on values larger than 32 or 64 bits Error See the HP Pascal for OpenVMS Language Reference Manual for more information on the types that are allocated more than 32 or 64 bits IMMHAVSIZ Type passed by immediate passing mechanism must have comp
306. s not improperly duplicate a key field or recreate the file specifying that the key field is permitted to be duplicated See Chapter 7 for more information KEYNOTDEF KEY nnn is not defined for this file Explanation Your program attempted a FINDK or RESETK procedure on an indexed file and the key number specified does not exist in the file User Action Correct the program so that the correct key numbers are used when accessing the file KEYVALINC key value is incompatible with the file s key nnn Explanation The key value specified for the FINDK procedure was incompatible in type or size with the key field of the file or your program attempted an OPEN on an existing file and the key check failed User Action Make sure that the correct key value is being specified for FINDK and OPEN Correct the program so that the type of the key value is compatible with the key of the file C 80 Diagnostic Messages LINTOOLON line is too long exceeded record length by nnn character s Explanation Your program attempted a WRITE PUT WRITEV or other output procedure on a text file that would have placed more characters in the current line than the record length of the file would allow The number of characters that did not fit is displayed in the message User Action Correct the program so that it does not place too many characters in the current line If appropriate use the WRITELN procedure or specify an increased record len
307. s otherwise unreachable but contains one or more labels is not eliminated unless the GOTO statement and the label itself are located in the same block 3 1 4 Code Hoisting from Structured Statements The compiler can improve the execution speed and size of programs by removing invariant computations from structured statements For example FOR j 1 TO i 23 DO BEGIN IF Selector THEN a i 23 j 14 0 ELSE b i 23 j 14 1 END If the compiler detected this IF statement it would recognize that regardless of the Boolean value of Selector a value is stored in the array component denoted by i 23 j 14 The compiler would change the sequence to the following t is I 23 FOR j 1 TO t DO BEGIN u j 14 IF Selector THEN a t u 0 ELSE b t u 1 END This removes the calculation of j 14 from the IF statement and the calculation of i 23 from both the IF statement and the loop Program Correctness Optimization and Efficiency 3 5 3 1 5 Inline Code Expansion for Predeclared Functions The compiler can often replace calls to predeclared routines with the actual algorithm for performing the calculation For example Square SQR a The compiler replaces this function call with the following and generates machine code based on the expanded call Square a a The program executes faster because the algorithm for the SQR function has already been included in the machine code
308. s you to use most of the features of RMS indexed files However if you wish to use segmented or null keys you must write a user action function When an existing indexed file is opened the run time library compares the keys in the file against the KEY attributes specified in the program If no KEY attribute was specified for the corresponding key in the indexed file then the comparison is bypassed and the open continues The run time library compares the position and the data type of the file s keys against the KEY attributes specified If the KEY attribute explicitly specifies a collating sequence ASCENDING or DESCENDING then the specified sequence must match that of the key in the file If no sequence is specified either sequence is allowed The CHANGES and DUPLICATES options are not checked For More Information e On user action functions Section 7 2 e On the OPEN procedure Section 7 1 6 e On indexed file organization and the KEY attribute HP Pascal for OpenVMS Language Reference Manual 7 1 2 OpenVMS Components and RMS Records In the HP Pascal I O model data items in a file are called components In RMS these items are called records 7 1 3 Count Fields for Variable Length Components Each variable length component contains a count field as a prefix This count field contains the number of bytes in the rest of the component For files on tape this count field is 4 bytes in length for files on disk this count field is 2 bytes
309. se the AND THEN and OR ELSE Boolean operators For More Information e On the order of expression evaluation see the description of the NOOPTIMIZE attribute HP Pascal for OpenVMS Language Reference Manual 3 16 Program Correctness Optimization and Efficiency 3 3 2 MAXINT and MAXINT64 Predeclared Constants The smallest possible value of the INTEGER type is represented by the predeclared constant MAXINT The largest possible value of the INTEGER type is represented by the predeclared constant MAXINT However the Itanium Alpha and VAX architectures support an additional integer value which is MAXINT 1 If your program contains a subexpression with this value the program s evaluation might result in an integer overflow trap Therefore a computation involving the value CMAXINT 1 might not produce the expected result To evaluate expressions that include CMAXINT 1 you should disable either optimization or integer overflow checking Similarly on OpenVMS I64 and OpenVMS Alpha systems MAXINT64 1 might not produce the expected results 3 3 3 Pointer References The compiler assumes that the value of a pointer variable is either the constant identifier NIL or a reference to a variable allocated in heap storage by the NEW procedure A variable allocated in heap storage is not declared in a VAR section and has no identifier of its own you can refer to it only by the name of a pointer variable followed by a circum
310. sed to open a nonexternal file See the HP Pascal for OpenVMS Language Reference Manual for more information REWNOTALL REWRITE is not allowed for a shared file Explanation Your program attempted a REWRITE procedure for a file for which the program did not have exclusive access REWRITE requires that no other users be allowed to access the file while the file s data is deleted Note that this message may also be issued if you do not have permission to write to the file User Action Correct the program so that the file is opened with SHARING NONE which is the default before performing a REWRITE procedure SETASGVAL set assignment value has element out of range Explanation Your program attempted to assign to a set variable a value that is outside the range specified by the variable s component type User Action Correct the assignment statement so that the value being assigned falls within the component type of the set variable See the HP Pascal for OpenVMS Language Reference Manual for more information on sets SETCONVAL set constructor value out of range Explanation Your program attempted to include in a set constructor a value that is outside the range specified by the set s component type or a value that is greater than 255 or less than 0 User Action Correct the constructor so that it includes only those values within the range of the set s component type See the HP Pascal for OpenVMS Language Reference Manual
311. ser Action Function llle eee Cascading Inheritance of Environment Files Inheritance Path of an Interface an Implementation and a Program uude ee qe HO IUS ee eT an S OR ago Cascading Using the Interface and Implementation ID oT C 65 2 17 2 18 4 5 4 13 6 4 6 10 7 12 2 3 2 8 Tables Lob dott ah WN ON O l k i h h l h h h h A l o L N 1 13 1 14 4 1 4 2 4 3 5 1 5 2 5 3 5 4 6 1 6 2 6 3 7 1 7 3 7 4 7 5 9 1 A 1 ALIGN Qualifier Options llle ARCHITECTURE Qualifier Options CHECK Qualifier Options 0 000000 eee eee DEBUG Qualifier Options 0 00 00 eee DESIGN Qualifier Options 20 0 0 0 0 ee eee ENUMERATION SIZE Qualifier Options FLOAT Qualifier Options 0 000 OPTIMIZE Qualifier Options 000 08 PLATFORMS Qualifier Options lessen SHOW Qualifier Options 00 0 0 ee eee STANDARD Qualifier Options 0 0005 TERMINAL Qualifier Options llle USAGE Qualifier Options 0 0 0 0 ccc eee Compilation Listing Contents and Qualifiers Placeholders Within the Declaration Section Placeholders Within the Executable Section Equivalent CDD Repository Language and HP Pascal Data TyYDes a a iame ex
312. ses to it will be inefficient COMNOTSIZ Component is not optimally sized Information The component indicated is not well sized and accesses to it will be inefficient COMNOTALNSIZE Component is not optimally aligned and sized Information The component indicated is not naturally aligned and sized accesses to it will be inefficient COMNOTPOS Fixed size field positioned after a run time sized field is not optimal Information Much better code can be generated for indicated component if it preceedes all of the run time sized fields CONTXTIGN Text following constant definition ignored Warning When defining constants with the CONSTANT DCL qualifier any text appearing after a valid constant definition is ignored CPPFILERR Unable to open included file Error CRETIMMOD Creation time for module module name in environment envi ronment file name differs from creation time in previous environments Warning Two or more PEN files referred to a module but the PEN files did not agree on the creation date time for the module This can occur if you recompile a module but do not recompile all the modules that inherited its PEN file Diagnostic Messages C 13 CSTRBADTYP Constructor only ARRAY RECORD or SET type CSTRCOMISS Constructor component s missing CSTRNOVRNT Constructor no matching variant CSTRREFAARR Repetition factor allowed only in ARRAY constructors CSTRREFAINT Repetition factor must be integer
313. sions you can write a routine that can have item lists with a number of cells that is determined at run time After the item list variable has been declared each cell must be filled in according to the system service and operation requested Consider the following example using the SYS TRNLNM system service VAR tem List Item List Template 2 ranslated Name VOLATILE VARYING 132 OF CHAR i HH Specify the buffer to return the translation tem List 1 Buffer Length SIZE Translated Name BODY Item List 1 Item_Code LNMS String Item List 1 Buffer Addr IADDRESS Translated Name BODY Item List 1 Return Addr IADDRESS Translated Name LENGTH Terminate the item list tem List 2 Terminator 0 Programming on OpenVMS Systems 6 15 The VAR section declares an item list with two cells It also declares an output buffer for the system service The VOLATILE attribute is used since the call to SYS TRNLNM indirectly writes into the variable The first cell is filled in with the operation desired the size of the output buffer the location to write the result and the location to write the size of the result Using the SIZE predeclared function prevents the code from having to be modified if the output buffer ever changes size Using the BODY and LENGTH predeclared fields of the VARYING string allows the system service to construct a valid VARYING OF CHAR string Finally the second cell
314. specified is inconsistent with this file Explanation The record length obtained from the file component s length or from the value of the record length parameter specified for the OPEN procedure was inconsistent with the actual record length of an existing file User Action Correct the program so that the record length specified if any is consistent with the file See Chapter 7 for more information RECTYPINC RECORD TYPE specified is inconsistent with this file Explanation The value of the RECORD LENGTH parameter specified for the OPEN procedure was inconsistent with the actual record type of an existing file User Action Correct the program so that the record type specified if any is consistent with the file See Chapter 7 for more information REFINAVAR read or write of inactive variant Explanation A field of an inactive variant was read or written User Action Correct the program so the variant is active or remove the reference to the inactive field Diagnostic Messages C 83 RESNOTALL RESET is not allowed on an unopened internal file Explanation Your program attempted a RESET procedure for a nonexternal file that was not open This operation is not permitted because RESET must operate on an existing file and there is no information associated with a nonexternal file that allows RESET to open it User Action Correct the program so that nonexternal files are opened before using RESET Either OPEN or REWRITE may be u
315. ssed the 2nd longword is either a 0 or a frame pointer for any uplevel references that the called routine may attempt to perform If you use the UNBOUND attribute on the PROCEDURE or FUNCTION parameter the compiler still passes the address of a BPV but the 5 20 Calling Conventions 2nd longword will always be zero If you use the IMMED foreign mechanism specifier along with the UNBOUND attribute HP Pascal will pass the address of the routine with the by immediate mechanism For example if you want to pass a Pascal routine to an external routine that just expects the address of the routine like a C routine or system service external procedure crtn immed unbound procedure p external procedure x begin end begin crtn x end Most system routines expect to be called in this fashion A few routines like EDT EDIT actually expect BPVs and not just entry point addresses On OpenVMS VAX HP Pascal only accepts a routine parameter by BPV To pass a routine from a non Pascal routine to a Pascal routine you must use the UNBOUND attribute on the formal routine parameter and you must pass the address of a longword containing the address of the routine s entry point Calling Conventions 5 21 6 Programming on OpenVMS Systems To eliminate duplication of programming and debugging efforts OpenVMS systems provide many routines to perform common programming tasks These routines are collectively known as sys
316. st performance on the target system The remainder of this section describes the different types of record layouts HP Pascal features that support them how to get the best performance with your data structures and how to convert existing code for better performance This section focuses on records but arrays also have similar properties In almost all cases where record fields are discussed you can substitute array components Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha 9 3 9 7 1 Natural Alignment VAX Alignment and Enumeration Sizes The compiler has the ability to lay out records in two ways e OpenVMS VAX alignment Fields and components less than or equal to 32 bits are allocated on the next available bit otherwise they are allocated on the next available byte e Natural alignment where an object is aligned based on its size Essentially fields and components are allocated on the next naturally aligned address for their data type For example 8 bit character strings should start on byte boundaries 16 bit integers should start at addresses that are a multiple of 2 bytes word alignment 82 bit integers and single precision real numbers should start at addresses that are a multiple of 4 bytes longword alignment 64 bit integers and double precision real numbers should start at addresses that are a multiple of 8 bytes quadword alignment For aggregates such as arrays and records th
317. stack frame for an inline user declared routine and no debugger symbol table information for the expanded routine Debugging the execution of an inline user declared routine is difficult and is not recommended To prevent conflicts between optimization and debugging you should always compile your program with a compilation switch that deactivates optimization until it is thoroughly debugged Then you can recompile the program which by default is optimized to produce efficient code For More Information e On debugging tools Chapter 4 e On compilation switches Chapter 1 3 22 Program Correctness Optimization and Efficiency 4 Programming Tools This chapter describes some Pascal specific assistance provided in the set of Hewlett Packard CASE tools For general information on each tool see the documentation for the tool This chapter provides information on e Section 4 1 Debugger Support for HP Pascal e Section 4 2 Language Sensitive Editor Source Code Analyzer Support for HP Pascal e Section 4 3 Accessing CDD Repository from HP Pascal 4 1 Debugger Support for HP Pascal In general the debugger supports the data types and operators of HP Pascal and the other debugger supported languages However there are important language specific limitations To get information on the supported data types and operators of any of the languages enter the HELP LANGUAGE command at the DBG gt prompt In general you can examine
318. stems you have to explicitly ask for natural alignment by using either a DCL qualifier or the corresponding attribute 1 Previous versions of HP Pascal used ALPHA AXP for this keyword The NATURAL keyword is now the recommended spelling for the same behavior The ALPHA AXP keyword will continue to be recognized for compatibility with old command lines Migrating from OpenVMS VAX to OpenVMS 164 or OpenVMS Alpha 9 5 To allow the compiler to do this placement you should refrain from using explicit positioning and alignment attributes on record fields unless required by your application The keyword PACKED should be avoided in all cases except e PACKED ARRAY OF CHARs require the PACKED keyword to be manipulated as strings Since chars are each 1 byte using the PACKED keyword does not hurt their performance in any way e PACKED SETSs may perform better than unpacked SETs For PACKED SETs the compiler can sometimes allocate fewer bits for the set field or variable These smaller sets can often be manipulated directly with longword or quadword instructions instead of using a generic run time library routine for larger sets Inside unpacked records PACKED SET fields are no slower than unpacked SET fields The same holds true for variables of PACKED SETs PACKED SETS of size 32 or 64 bits are the best performing set types otherwise a multiple of 8 bits improves performance to a lesser degree You may still need to use PACKED if you rely
319. support to deal with null terminated strings For More Information e HP Pascal Language Reference Manual When passing strings to an HP Pascal routine from another language you must use a descriptor if the Pascal formal parameter is a conformant parameter HP Pascal cannot accept a conformant parameter with the by reference mechanism For conformant array parameters you must generate a CLASS_A descriptor on OpenVMS or a CLASS_NCA descriptor on OpenVMS Alpha unless you select another descriptor class using the CLASS 5 CLASS A or CLASS NCA attributes For conformant varying parameters you must generate a CLASS VS descriptor on both platforms Calling Conventions 5 19 If you wish to use the by reference mechanism to pass strings into a Pascal routine you must define a Pascal datatype that represents a fixed length string or varying string with a maximum size and use that datatype in the formal parameter definition The HP Pascal schema type STRING is passed by CLASS VS descriptor Other HP Pascal schema types use private data structures when passed between routines and cannot be accessed from routines written in other languages 5 4 3 Passing Routine Parameters between HP Pascal and Other Languages On OpenVMS 164 Systems By default HP Pascal on OpenVMS 164 systems passes the address of a function descriptor for PROCEDURE or FUNCTION parameters The presence of the UNBOUND attribute or the IMMED foreign mechanism sp
320. systems contents of 5 5 CASE statement effect on efficiency 3 14 run time checking of 1 7 CDD Repository accessing from source program 4 9 creating directory hierarchies 4 8 4 9 definition of 4 8 entering definitions 4 9 equivalent HP Pascal data types 4 10 to 4 12 example of use 4 12 HP Pascal support of 4 8 CDDL 4 9 Character string as function results 5 2 run time checking of 1 7 CHECK attribute C 25 effect on efficiency 3 15 CHECK qualifier 1 7 CHF 8 1 CLASS A attribute 5 13 CLASS NCA attribute 5 13 CLASS S attribute 5 13 CLASS VS descriptor used with LIB FIND_ FILE 6 17 CLOSE procedure with user action parameters 7 10 Code scheduling 3 10 Index 2 Comment processing OpenVMS VAX systems 4 3 Common Data Dictionary See CDD Repository Common Data Dictionary Language See CDDL Compilation statistics in listing file 1 28 Compilation switch See Compile time qualifiers Compilation unit 2 1 Compiler command qualifiers 1 3 to 1 25 diagnostics C 1 generated labels 3 11 invoking 1 1 Compiler information 1 25 Compile time qualifiers 1 3 to 1 25 Compiling for optimal performance 3 13 Condition handler controlling execution 8 4 declaring parameters for 8 6 definition of 8 1 establishing 8 4 examples of 8 11 for faults 8 10 for traps 8 10 overview of 8 3 performing I O to and from 8 5 removing 8 5 reporting conditions 8 4 return
321. t You should take care that your use of the RMS FAB does not interfere with the normal operations of the OpenVMS Run Time Library RTL Future changes to the RTL may change the way in which the FAB is used which may in turn require you to change your program For More Information e On the OpenVMS Run Time Library HP OpenVMS Programming Concepts Manual Entry Points to HP Pascal Utilities B 1 B 2 PASSRAB f The PAS RAB function returns a pointer to the RMS record access block RAB of file f After this function has been called the RAB can be used to get information about the file and to access RMS facilities not explicitly available in the HP Pascal language The component type of file f can be any type the file must be open PAS RAB is an external function that must be explicitly declared by a declaration such as the following TYPE Unsafe File UNSAFE FILE OF CHAR Ptr to RAB RABSTYPE FUNCTION PASSRAB VAR F Unsafe File Ptr to RAB EXTERN This declaration allows a file of any type to be used as an actual parameter to PAS RAB The type RAB TYPE is defined in the HP Pascal environment file STARLET PEN which your program or module can inherit You should take care that your use of the RMS RAB does not interfere with the normal operations of the OpenVMS Run Time Library Future changes to the RTL may change the way in which the RAB is used which may in turn require you to change your program Fo
322. t and Enumeration uu MN CP Sindee DORN Ge Mea OEE de at dope ae ae dee we HP Pascal Features Affecting Data Alignment and Size Optimal Record Layout 0 0 0 cc eee Optimal Data Size 6 ee es Converting Existing Records 0000 c eee eee Applications with No External Data Dependencies Applications with External Data Dependencies A Errors Returned by STATUS and STATUSV Functions 9 1 9 1 9 2 9 2 9 2 vii B Entry Points to HP Pascal Utilities PASSPABC oos ders aneeeenGesameeuseeeerereeeaneees PAS RAB I racine dines aac VA Ve Ricco ROUEN aleae PAS MARK2 s oo eshocR on IHE E TER DUST etre PASS RELEASEX p eee hee C Diagnostic Messages C 1 C 2 Index Examples 2 1 2 2 2 3 4 1 4 2 4 3 6 1 6 2 7 1 Figures 2 1 2 2 2 3 viii Compiler Diagnostics llle Run Time Diagnostics leen An Interface Module for Graphics Objects and Routines An Implementation Module for Graphics Objects and ROUUNES TP m A Graphics Main Program 000000 eee Using LSE to Create a FOR Statement Using LSE Comments in Program Design OpenVMS VAX Systems oa eravaig dede Alea a aoe anos sd de aca E ya P ei d Using DICTIONARY to Access a Oracle CDD Repository Record Definition 5 i253 23a ke 9 E SE Inheriting STARLET PEN to Call SYS HIBER Using GETJPIW to Retrieve a Process Name U
323. t command file Set when file is closed depends on when closed DISPOSITION FAB V_SQO Sequential only 1 if ACCESS_METHOD SEQUENTIAL default continued on next page Input and Output Processing 7 5 Table 7 2 Cont Setting of RMS File Access Block Fields by a Call to the OPEN Procedure Field Name OPEN Parameters and Value FAB V TEF Truncate at end of file Initialized to 0 set to 1 after REWRITE or TRUNCATE of a sequential organization file FAB V TMD Temporary marked for 1 if nonexternal file with no FILE NAME deletion specified and DISPOSITION DELETE specified or implied FAB B_FSZ Fixed control area size 2 if terminal file enabled for prompting FAB W_IFI Internal file identifier Returned by RMS FAB W_MRS Maximum record size RECORD_LENGTH if specified file component size if ORGANIZATION is not SEQUENTIAL or if RECORD_ TYPE FIXED FAB L NAM Name block address Set to address of name block the expanded and resultant string areas are set up but the related file name string is not FAB B ORG File organization FAB C REL if ORGANIZATION RELATIVE FAB C IDX if ORGANIZATION INDEXED FAB C SEQ in all other cases FAB B RAT Record attributes FAB V FTN FORTRAN carriage 1 if CARRIAGE CONTROL FORTRAN control FAB V CR Add LF and CR 1 if CARRIAGE CONTROL LIST default for TEXT and VARYING OF CHAR files FAB V PRN Print file format 1 if terminal file enabled for prompting lAfter the call to OPEN
324. t further describes the problem User Action Make sure that you are specifying the correct file See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the additional RMS message FILNOTGEN file is not in Generation mode Explanation Your program attempted a file operation that required the file to be in generation mode ready for writing User Action Modify the program to use a REWRITE TRUNCATE or LOCATE procedure to place the file in generation mode as appropriate See Chapter 7 for more information FILNOTINS file is not in Inspection mode Explanation Your program attempted a file operation that required the file to be in inspection mode ready for reading User Action Modify the program to use a RESET RESETK FIND or FINDK procedure to place the file in inspection mode as appropriate See Chapter 7 for more information FILNOTKEY file is not opened for keyed access Explanation Your program attempted to execute a FINDK RESETK DELETE or UPDATE procedure on a file that was not opened for keyed access User Action Modify the program to specify the ACCESS METHOD KEYED parameter to the OPEN procedure when opening the file See Chapter 7 to make sure that keyed access is appropriate to your application FILNOTOPE file is not open Explanation Your program attempted to execute a file manipulation procedure on a file that was not open User Action Correct the program to op
325. t in the appropriate OpenVMS reference manual The documentation for each routine describes the routine s purpose the declaration format the return value and any required or optional parameters Detailed information about each parameter is listed in the description The following format is used to describe each parameter parameter name OpenVMS Usage OpenVMS data type type i parameter data type access parameter access mechanism parameter passing mechanism Using this information you must determine the parameter s data type type the parameter s passing semantics access the mechanism used to pass the parameter mechanism and whether the parameter is required or optional from the call format The following sections describe the methods available in HP Pascal to obtain the various data types access methods and passing mechanisms 6 2 1 Methods Used to Obtain OpenVMS Data Types The data specified by a parameter has a data type Several OpenVMS standard data types exist system routine parameter must use one of these data types For More Information e On OpenVMS data types and equivalent HP Pascal declarations HP OpenVMS Calling Standard 6 2 2 Methods Used to Obtain Access Methods The access method describes the way in which the called routine accesses the data specified by the parameter The following three methods of access are the most common e Read only data must be read by the called routine The
326. t of range Error See the HP Pascal for OpenVMS Language Reference Manual for details on the range of real numbers REALOPNDREQ Real SINGLE DOUBLE or QUADRUPLE operand s required Error RECHASFILE Record contains one or more FILE components POS is illegal Error RECHASTMSTMP Record contains one or more TIMESTAMP components POS is illegal Error RECLENINT RECORD LENGTH expression must be of type integer Error The value of the record length parameter to the OPEN procedure must be an integer RECLENMNGLS RECORD LENGTH parameter is meaningless given file s type Warning The record length parameter is usually relevant only for files of type TEXT and VARYING OF CHAR RECMATCHTYP MATCH TYPE identifier NXT or NXTEQL is recommended instead of GTR or GEQ Information REDECL A declaration of symbol name already exists in block name Error You cannot redeclare an identifier or a label in the same block in which it was declared Inheriting an environment is equivalent to including all of its declarations at program or module level REDECLATTR attribute name already specified Error Only one member of a particular attribute class can appear in the same attribute list REDECLFLD Record already contains a field field name Error The names of the fields in a record must be unique they cannot be duplicated between variants C 42 Diagnostic Messages REINITVAR variable name has alread
327. t program by leaving it disabled e When a variable is accessed by a program block other than the one in which it was declared the variable should have static rather than automatic allocation An automatically allocated variable has a varying location in memory accessing it in another block is time consuming and less efficient than accessing a static variable e On OpenVMS VAX systems avoid using the same temporary variable many times in the course of a program Instead use a new variable every time your program needs a temporary variable Because variables stored in registers are the easiest to access your program is most efficient when as many variables as possible can be allocated in registers If you use several different temporary variables the lifetime of each one is greatly reduced thus there is a greater chance that storage for them can be allocated in registers rather than at memory locations e When creating schema records or records with nonstatic fields place the fields with run time size at the end of the record The generated code has to compute the offset of all record fields after a field with run time size and this change minimizes the overhead For More Information e On HP Pascal language elements and on attributes HP Pascal for OpenVMS Language Reference Manual On compilation switches Chapter 1 Program Correctness Optimization and Efficiency 3 15 3 3 Implementation Dependent Behavior The Pascal
328. tem routines They include routines in the run time library to assist you in such areas as mathematics screen management and string manipulation Also included are OpenVMS Record Management Services RMS which are used to access files and their records There are also system services that perform tasks such as resource allocation information sharing and input output coordination This chapter discusses the following topics e Section 6 1 Using System Definitions Files e Section 6 2 Declaring System Routines e Section 6 3 Calling System Routines e Section 6 4 Using Attributes e Section 6 5 Using Item Lists e Section 6 6 Using Foreign Mechanism Specifiers on Actual Parameters e Section 6 7 Using 64 Bit Pointer Types Because all OpenVMS system routines adhere to the HP OpenVMS Calling Standard you can declare any system routine as an external routine and then call the routine from an HP Pascal program 6 1 Using System Definitions Files To access system entry points data structures symbol definitions and messages HP Pascal provides files that you can inherit PEN or include PAS in your application Table 6 1 summarizes the source and environment files that HP Pascal makes available to you in the directory SYS LIBRARY for instance SYS LIBRARY STARLET PEN Programming on OpenVMS Systems 6 1 Table 6 1 HP Pascal Definitions Files File Description System Services Definitions File STARLET PAS P
329. the architecture has additional instructions that can modify byte and word sized data directly See the ARCHITECTURE qualifier for additional information On OpenVMS 164 systems the compiler may use quadword instructions to update unaligned variables unless modified by use of the GRANULARITY qualifier 1 14 Compiling HP Pascal Programs INCLUDE directory Allows you to specify search locations for INCLUDE directives and INHERIT attributes that specify file names without explicit disk or directory specifications The qualifier takes a list of directories to search The compiler applies the INCLUDE information to the following Pascal constructs e 9 INCLUDE name or 4 INCLUDE name ext e INHERIT name or INHERIT name ext e INCLUDE name modname or INCLUDE name ext modname The compiler searches as follows 1 The current directory with a default extension of pas for INCLUDE directives pen for INHERIT attributes and tlb for INCLUDE from text libraries just like before 2 Any directories specified with the INCLUDE qualifer in the order specified with the appropriate default extension 3 SYS LIBRARY with the appropriate default extension NO LIST NOLIST interactive default LISTzinput file name LIS batch default Produces a source listing file with a file type of LIS See the SHOW qualifier for more information on controlling the contents of the source listing fil
330. the following example PASCAL CONSTANT MSG String with a x22 double quote character Compiling HP Pascal Programs 1 9 To use a single quote string literal with CONSTANT enclose the entire name value clause in double quotes to prevent DCL from trying to perform symbol substitution when it sees the single quote character For example PASCAL CONSTANT MSG Single quoted literal In this case the double quotes are discarded by the compiler and the single quoted string literal is processed However using double quoted literals with CONSTANT is easier and more flexible The extended string syntax for string literals is not supported on the command line The extended string syntax is as follows pesa ess These extended string literals are constant expressions not simple literals printing string constant expression printing string constant expression To insert nonprintable characters into a string literal from the command line you can use a double quoted string literal and the M xnn escape sequence NOJCROSS REFERENCE NOCROSS REFERENCE default Produces a cross reference section within the listing file The compiler ignores this qualifier if you do not also specify LIST on the same command line NO DEBUG DEBUG TRACEBACK default Specifies that the compiler is to generate information for use by the debugger and the run time error traceback mechanism A single identifier or a list of identifie
331. ting point registers designated as F16 to F21 Information about the parameter list is passed in the argument information register R25 The first byte of the register specifies the parameter count Arguments beyond 6 are passed on the top of the stack On OpenVMS VAX systems the parameters are a sequence of longword 4 byte entries pointed to by the array pointer AP The first byte of the first entry in the list is a parameter count which indicates how many parameters follow in the list The form in which the parameters in the list are represented is determined by the passing mechanisms you specify in the formal parameter list and the values you pass in the actual parameter list The parameter list contains the actual parameters passed to the routine 5 1 2 Function Return Values In HP Pascal a function returns to the calling block the value that was assigned to its identifier during execution HP Pascal chooses one of three methods for returning this value The method chosen depends on the amount of storage required for values of the type returned as follows On OpenVMS 164 Systems e An nonfloating point scalar type a schematic subrange an array a record or set with size less than 64 bits is returned in the first integer register designated as r8 If the value is less than 64 bits r8 is sign extended or zero extended depending on the type e A floating point value that can be represented in 64 bits of storage is returned
332. tion Negation NONE Disables standards checking N A ANSI Uses the rules of the ANSI standard N A ISO Uses the rules of the ISO standard N A EXTENDED Uses the rules of the Extended N A standard VALIDATION Performs validation for the given NOVALIDATION standard The STANDARD qualifier allows you to use only two options The first option selects the standard to be used ANSI ISO or EXTENDED The second option determines whether the strict validation rules are to be enforced NO JVALIDATION STANDARD ANSI ISO VALIDATION is not allowed because both ANSI and ISO are specified By default these information level messages are written to the error file SYS ERROR Using the VALIDATION option changes all nonstandard information level messages to error level messages The STANDARD qualifier without options is equivalent to STANDARD ANSI NOVALIDATION STANDARD VALIDATION is equiv alent to STANDARD ANSI VALIDATION The negation NOSTANDARD is equivalent to STANDARD NONE 1 20 Compiling HP Pascal Programs NO SYNCHRONOUS EXCEPTIONS OpenVMS Alpha systems only NOSYNCHRONOUS EXCEPTIONS default Specifies that the compiler should generate code to insure that exceptions are reported as near as possible to the instruction that generated the exception This can avoid confusion in tracing the source of an exception however there is a performance penalty for using this qualifier NO TERMINAL NOTERMINAL default
333. tructions for PCA56 processors 21164PC chips This option permits the compiler to generate any EV4 instruction plus any instructions contained in the BWX and MAX extensions However HP Pascal does not generate any of the instructions in the MAX multimedia extension to the Alpha architecture continued on next page Compiling HP Pascal Programs 1 5 Table 1 2 Cont ARCHITECTURE Qualifier Options Option Action Default Information EV6 Generate instructions for EV6 processors 21264 chips This option permits the compiler to generate any EV4 instruction any instruction contained in the BWX and MAX extensions plus any instructions added for the EV6 chip These new instructions include a floating point square root instruction SQRT integer floating point register transfer instructions and additional instructions to identify extensions and processor groups Applications compiled with this option may incur emulation overhead on EV4 EV5 EV56 and PCA56 processors EV6 Generate instructions for EV7 processors 21364 chips This option permits the compiler to generate any EV67 instruction There are no additional instructions available on the EV7 processor but the compiler does have different instruction scheduling and prefetch rules for tuning code for the EV7 Applications compiled with this option may incur emulation overhead on EV4 EV5 EV56 and PCA56 processors EV67 Generate instructions for E
334. tructor is only defined at the outer level of a record IVQUALFILE Illegal switch switch name on file specification Warning Only the LIST and NOLIST qualifiers are allowed on the file specification of a INCLUDE directive IVQUOCHAR Illegal nonprinting character ASCII nnn within quotes Warning The only nonprinting characters allowed in a quoted string are the space and tab the use of other nonprinting characters in a string causes this warning To include nonprinting characters in a string you should use the extended string syntax described in the HP Pascal for OpenVMS Language Reference Manual IVRADIX Invalid radix was specified in the extended number Error IVRADIXDGIT Illegal digit in binary octal or hexadecimal constant Error IVREDECL Illegal redeclaration gives symbol name multiple meanings in scope name IVREDECLREC Illegal redeclaration gives symbol name multiple meanings in this record IVREDEF Illegal redefinition gives symbol name multiple meanings in scope name Warning When an identifier is used in any given block it must have the same meaning wherever it appears in the block IVUSEALIGN Invalid use of alignment attribute IVUSEALLOC Invalid use of allocation attribute Error IVUSEATTR Invalid use of attribute name attribute Error The use of an attribute on a variable parameter or routine conflicts with the requirements of the object s type IVU
335. u can also provide an initial state for this type using a constructor as follows Shape t Shape Types RECORD Coordinate X Coordinate Y REAL CASE t OF Square Height Width REAL Circle Radius READ END VALUE Coordinate X 50 0 Coordinate Y 50 0 CASE Circle OF Radius 5 0 If you use constructors for variant records you can only specify an initial state for one of the variant values If you need to specify initial states for all variant values you must specify the initial states on the individual variants as shown in Example 2 1 The interface module also declares routines that can draw rotate scale and delete an object of type Shape The bodies of these routines are located in the implementation module The interface module also contains a TO BEGIN DO section as shown in the following code fragment HIDDEN PROCEDURE Draw Logo EXTERNAL Before program execution display a logo to which the main program has no access TO BEGIN DO Draw Logo As with the other routines the body of Draw Logo is located in the implementation module The HIDDEN attribute prevents compilation units that inherit the interface environment file from calling the Draw Logo routine This ensures that the application only calls Draw Logo once at the beginning of the application Separate Compilation 2 13 Using this design the interface module can provide graphical data and tools to be used by other comp
336. u can use the GOTO statement to exit from a loop but careless use of it interferes with both optimization and the straightforward analysis of program flow e Enclose in parentheses any subexpression that occurs frequently in your program The compiler checks whether any assignments have affected the subexpression s value since its last occurrence If the value has not changed the compiler recognizes that a subexpression enclosed in parentheses has already been evaluated and does not repeat the evaluation For example ib c 3 14 Program Correctness Optimization and Efficiency The compiler evaluates the subexpression b c as a result of performing the SIN function When it is encountered again the compiler checks to see whether new values have been assigned to either b or c since they were last used If their values have not changed the compiler does not reevaluate b c e Once your program has been completely debugged disable all checking with CHECK NONE or with the appropriate compilation switch Recall that HP Pascal enables bounds and declaration checking by default When no checking code is generated more optimizations can occur and the program executes faster Integer overflow checking is disabled by default If you are sure that your program is not in danger of integer overflow you should not enable overflow checking Because overflow checking precludes certain optimizations you can achieve a more efficien
337. u should consider changing it to use the current versions OCT or HEX predeclared functions VALOUTBND Value to be assigned is out of bounds Error A value specified in an array or record constructor exceeds the subrange defined as the type of the corresponding component VALUEINIT VALUE variables must be initialized Error Variables with both the VALUE and GLOBAL attributes must be given an initial value in either the VAR section or in the VALUE section VALUETOOBIG VALUE attribute not allowed on objects larger than 32 bits Error Variables with the VALUE attribute cannot be larger than 32 bits because they are expressed to the linker as global symbol references VALUETYP VALUE allowed only on ordinal or real types Error VALUEVISIB GLOBAL or EXTERNAL visibility is required with the VALUE attribute Error Variables with the VALUE attribute must be given either external or global visibility If the variable is given global visibility then it must also be given an initial value VARCOMFRML Variable is not compatible with formal parameter formal parameter name Error A variable being passed as an actual parameter is not compatible with the corresponding formal parameter indicated Variable parameters must be structurally compatible The reason for the incompatibility is provided in an informational message that the compiler prints along with this error message Diagnostic Messages C 63 VARNOTEXT Variable must
338. uch as the Language Sensitive Editor Source Code Analyzer LSE SCA NOJARCHITECTURE ARCHITECTURE GENERIC default OpenVMS Alpha systems only Specifies which version of the Alpha architecture instructions should be generated for All Alpha processors implement a core set of instructions and in some cases the following extensions BWX byte and word manipulation instructions and MAX multimedia instructions See the Alpha Architecture Reference Manual for additional information Table 1 2 lists the available keywords 1 4 Compiling HP Pascal Programs Table 1 2 ARCHITECTURE Qualifier Options Option Action Default Information GENERIC Generate instructions that are appropriate This option is the default for all Alpha processors HOST Generate instructions for the processor on which the compiler is running for example EV56 instructions on an EV56 processor and EV4 instructions on an EV4 processor EV4 Generate instructions for the EV4 EV5 processor 21064 20164A 21066 and 21068 chips and EV5 processor some 21164 chips Note that the EV5 and EV56 processors both have the same chip number 21164 EV56 Generate instructions for EV56 processors some 21164 chips This option permits the compiler to generate any EV4 instruction plus any instructions contained in the BWX extension Applications compiled with this option may incur emulation overhead on EV4 and EV5 processors PCA56 Generate ins
339. unexpected error during execution of an EXTEND procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for the description of the RMS error ERRDURFIN error during FIND or FINDK Explanation RMS reported an unexpected error during execution of a FIND or FINDK procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for the description of the RMS error ERRDURGET error during GET Explanation RMS reported an unexpected error during execution of the GET procedure The RMS error message is also displayed User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for the description of the RMS error ERRDURMAR error during MARK Explanation An error occurred during execution of the PASSMARK2 procedure An additional message is displayed that further describes the error User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the additional message ERRDURNEW error during NEW Explanation An error occurred during execution of the NEW procedure An additional message is displayed that further describes the error User Action See the OpenVMS System Messages and Recovery Procedures Reference Manual for a description of the additional message Diagnostic Messages C 69 ERRDUROPE error du
340. utable images is the EXE file type The LINK command format is as follows LINK command qualifier file spec ile qualifier J file spec qualifier library module h library module Compiling HP Pascal Programs 1 31 command qualifier The name of a qualifier that indicates special processing to be performed by the linker on all files listed file spec The name of one of the following e The input file which can be the name of an object module library that contains the object code to be linked e The options file used only with the OPTIONS qualifier e The output file used only with the EXECUTABLE and MAP qualifiers file qualifier The name of a qualifier the INCLUDE LIBRARY or OPTIONS qualifier that indicates special processing to be performed by the linker on the files to which the qualifier is attached library module The name of one or more object modules or shareable image libraries that you can only specify using the INCLUDE or LIBRARY qualifiers A source program or module cannot run on the system until it is linked If you are using PEN Pascal Environment files that include variables procedures or functions make sure you link the object file into the EXE file When you execute the LINK command the OpenVMS Linker performs the following functions e Resolves local and global symbolic references in the object code e Assigns values to the global symbol
341. value of 8 7 system defined 8 3 writing of 8 4 to 8 16 Condition handlers returning SS CONTINUE 8 9 Condition Handling Facility See CHF Condition signal 8 3 Condition value 8 8 definition of 8 2 for faults 8 11 for traps 8 11 Condition value cont d matching 8 8 severity code of 8 8 Conformant array parameters different descriptor classes 9 3 CONSTANT qualifier 1 8 Constants compile time evaluation of 3 3 effect on efficiency 3 14 Constructor for schema variant record example 2 13 using OTHERWISE example 2 1 Conversion of constants 3 3 Cross reference section in listing file 1 27 CROSS REFERENCE qualifier 1 10 with MAP on LINK command 1 34 D Data conversion 9 3 Data layout 9 3 Data structure parameters 6 9 Data type initial state specifier for 2 13 Data types D floating restrictions 4 10 G floating restrictions 4 10 HP Pascal and CDDL equivalent 4 10 Debugger HP Pascal support of assignment compatibility 4 1 automatic variables 4 2 examining LENGTH field 4 2 type cast operator 4 2 unreferenced variables 4 1 Debugging effects of optimization 3 21 DEBUG qualifier use with NOOPTIMIZE qualifier 1 11 with LINK command 1 33 with PASCAL command 1 10 DEBUG qualifier cont d with RUN command 1 37 Declaration section multiply declared identifiers 2 4 Declaration sharing 4 8 to 4 13 Default parameters in system services 6 11
342. variable as an actual parameter using 6REF DESCR or STDESCR 6 2 3 Methods Used to Obtain Passing Mechanisms The way in which an argument specifies the actual data to be used by the called routine is defined in terms of the parameter passing mechanism Table 6 3 lists all passing mechanisms that may appear under the mechanism entry in an argument description and the method used in HP Pascal to obtain the passing mechanism Table 6 3 Mechanism Type Translations Mechanism Entry Method Used in HP Pascal By value IMMED or IMMEDIATE By reference VAR REF or REFERENCE or default continued on next page Programming on OpenVMS Systems 6 7 Table 6 3 Cont Mechanism Type Translations Mechanism Entry Method Used in HP Pascal By descriptor Fixed length Dynamic string Array Procedure Decimal string Noncontiguous array Varying string Varying string array STDESCR parameter of type PACKED ARRAY OF CHAR or CLASS S STDESCR parameter of type PACKED ARRAY OF CHAR or CLASS S Array type conformant array parameter or CLASS A N A N A DESCR or CLASS_NCA Value VAR or DESCR conformant parameter of type VARYING OF CHAR or DESCR parameter of type VARYING OF CHAR Value VAR or DESCR conformant parameter of type array of VARYING OF CHAR or DESCR parameter of type array of VARYING OF CHAR Unaligned bit N A string Unaligned bit array N A String with bounds N
343. wise noted Nondecimal radixes binary octal or hexadecimal are explicitly indicated 1 Compiling HP Pascal Programs After you use a text editor to write code to a file you use Digital Command Language DCL commands to compile modules and programs and to link and run programs This chapter covers the following topics e Section 1 1 PASCAL Command e Section 1 2 LINK Command e Section 1 3 RUN Command e Section 1 4 Error Messages For information on DCL syntax see HELP or the OpenVMS documentation set 1 1 PASCAL Command The PASCAL command invokes the HP Pascal compiler which verifies program source statements issues error messages and generates and groups machine language instructions into an object module for the linker The default for compiler output files object modules is the OBJ file type The Pascal command format is as follows PASCAL command qualifier file spec file qualifier sd file spec identifier Iqualitier f a e j name identifier directory Compiling HP Pascal Programs 1 1 command qualifier The name of a qualifier that indicates special processing to be performed by the compiler on all files listed file spec The name of one of the following e The input source file that contains the program or module to be compiled If you separate multiple source file specifications with commas the programs are compiled separately If you separate
344. xamples of Condition Handlers An exception condition is an event usually an error that occurs during program execution and is detected by system hardware or software or the logic in a user application program A condition handler is a routine that is used to resolve exception conditions By default the Condition Handling Facility CHF provides condition handling sufficient for most HP Pascal programs The CHF also processes user written condition handlers The use of condition handlers requires considerable programming experience You should understand the discussions of condition handling in the following volumes before attempting to write your own condition handler e HP OpenVMS Programming Concepts Manual e HP OpenVMS System Services Reference Manual e HP OpenVMS Calling Standard Error Processing and Condition Handling 8 1 8 1 Condition Handling Terms The following terms are used in the discussion of condition handling Condition value An integer value that identifies a specific condition Stack frame A standard data structure built on the stack during a routine call starting from the location addressed by the frame pointer FP and proceeding to both higher and lower addresses it is popped off the stack during the return from a routine Routine activation The environment in which a routine executes This environment includes a unique stack frame on the run time stack the stack frame contains the address of a conditi
345. y been initialized Error Variables are the only data items that can be initialized and they can be initialized only once REPCASLAB Value has already appeared as a label in this CASE statement Error You cannot specify the same value more than once as a case label in a CASE statement REPFACZERO Repetition factor cannot be the function ZERO REQCLAORNCA Arrays and conformants of this parameter type require either CLASS A or CLASS NCA REQCLS Scalars and strings of this parameter type require CLASS S Error REGNATAGN Operand must be naturally aligned Error REQNOCH Primary key requires NOCHANGES option Error REQPKDARR The combination of CLASS S and STDESCR requires a PACKED ARRAY OF CHAR structure Error REQREADVAR READ or READV requires at least one variable to read into Error The READ and READV procedures require that you specify at least one variable to be read from a file REQWRITELEM WRITE requires at least one write list element Error The WRITE procedure requires that you specify at least one item to be written to a file RESPTRTYP Result must be a pointer type Information REVRNTLAB Value has already appeared as a label in this variant part Error You cannot specify the same value more than once as a case label in a variant part of a record Diagnostic Messages C 43 RTNSTDESCR Routines cannot be passed using STDESCR Error SCHCONST Nonstatic constants are not allowed Err
346. y for the handler to supply a value Error Processing and Condition Handling 8 13 Example 5 ASYNCHRONOUS FUNCTION Handler 4 VAR SA Sig Args VAR MA Mech Args UNSAFE INTEGER BEGIN IF LIBSMATCH COND SA 1 condition name THEN GOTO 99 Handler 4 SS RESIGNAL END ves um 0 A handler can force control to resume at an arbitrary label in its scope Note that this reference is to a label in an enclosing block because a GOTO to a local label will remain within the handler In accordance with the HP OpenVMS Calling Standard HP Pascal implements references to labels in enclosing blocks by signaling SS _ UNWIND in all stack frames that must be deleted Example 6 FUNCTION EXP With Status X REAL VAR Status INTEGER REAL FUNCTION MTHSEXP A REAL REAL EXTERNAL ASYNCHRONOUS FUNCTION Math Error VAR SA Sig Args VAR MA Mech Args UNSAFE BEGIN Math Error INTEGER IF LIBSMATCH COND SA 1 MTH FLOOVEMAT MTH FLOUNDMAT 0 THEN BEGIN IF ODD Status THEN Status SA 1 Cond Status Math Error SS CONTINUE END ELSE Math Error SS RESIGNAL END BEGIN EXP With Status STATUS SS SUCCESS ESTABLISH Math Error EXP With Status MTHSEXP X END 8 14 Error Processing and Condition Handling record condition status if no previous error condition handled propagate no further propagate condition status to other handlers
347. ying this attribute provides you with more power in deciding which routines should be inlined Note There is no stack frame for an inline user declared routine and no debugger symbol table information for the expanded routine Debugging the execution of an inline routine is difficult and is not recommended 3 1 8 Operation Rearrangement The compiler can produce more efficient machine code by rearranging operations to avoid having to negate and then calculate the complement of the values involved For example c b a Program Correctness Optimization and Efficiency 3 7 If a program includes this operation the compiler rearranges the operation to read as follows c a b These two operations produce the same result but because the compiler has eliminated negation or complement operations the machine code produced is more efficient 3 1 9 Partial Evaluation of Logical Expressions 3 1 10 The Pascal language does not specify the order in which the components of an expression must be evaluated If the value of an expression can be determined by partial evaluation then some subexpressions may not be evaluated at all This situation occurs most frequently in the evaluation of logical expressions For example WHILE i lt 10 AND alil lt gt 0 DO BEGIN ali ali 1 i i 1 END In this WHILE statement the order in which the two subexpressions i lt 10 and ali lt gt 0 are

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