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HP OpenVMS Systems

C Programming Language
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System_Identification_Macros

Each implementation of the HP C compiler automatically defines macros that you can use to identify the system on which the program is running. These macros can assist in writing code that executes conditionally, depending on the architecture or operating system on which the program is running. The following table lists the traditional and new spellings of these predefined macro names for HP C on OpenVMS systems. Both spellings are defined for each macro unless ANSI C mode is in effect (/STANDARD=ANSI89), in which case only the new spellings are defined. Traditional spelling New spelling vms __vms VMS __VMS vms_version __vms_VERSION VMS_VERSION __VMS_VERSION __VMS_VER __DECC_VER __DECCXX_VER vaxc __vaxc VAXC __VAXC vax11c __vax11C VAX11C __VAX11C --- __DECC --- __STDC__ __STDC_HOSTED__ __STDC_VERSION__ __STDC_ISO_10646__ __MIA On OpenVMS I64 Systems, HP C also supports the following predefined system identification macro names in all compiler modes: __ia64 __ia64__ __32BITS __INITIAL_POINTER_SIZE Predefined macros (with the exception of __STDC_VERSION__, __STDC_ISO_10646__, vms_version, VMS_VERSION, __vms_version, __VMS_VERSION, and __INITIAL_POINTER_SIZE) are defined as 1 or 0, depending on the system you're compiling on (VAX or Alpha processor), the compiler defaults, and the qualifiers used. For example, if you compiled using G_floating format, then __D_FLOAT and __IEEE_FLOAT (Alpha processors only) are predefined to be 0, and __G_FLOAT is predefined as if the following were included before every compilation unit: #define __G_FLOAT 1 These macros can assist in writing code that executes conditionally. They can be used in #elif, #if, #ifdef, and #ifndef directives to separate portable and nonportable code in a HP C program. The vms_version, VMS_VERSION, __vms_version, and __VMS_VERSION macros are defined with the value of the OpenVMS version on which you are running (for example, Version 6.0). The __STDC__ macro is defined to 1 for /STANDARD options ANSI89, C99, LATEST and MIA. It is defined to 2 for /STANDARD=RELAXED and to 0 for /STANDARD=MS. It is not defined for /STANDARD options VAXC and COMMON. The __STDC_HOSTED__ macro is defined to 1 for /STANDARD=c99 and /STANDARD=LATEST. It is not defined for all other /STANDARD keywords. The __STDC_VERSION__ macro is defined to 199901L for /STANDARD keywords C99, LATEST, RELAXED, MS, PORTABLE. It is defined to 199409L when the ISOC94 keyword is specified alone or with the ANSI89, MIA, RELAXED, MS, PORTABLE, or COMMON modes. The macro is undefined for the VAXC keyword or for keywords ANSI89, MIA, or COMMON without ISOC94 specified. The __STDC_ISO_10646__ macro evaluates to an integer constant of the form yyyymmL (for example, 199712L), intended to indicate that values of type wchar_t are the coded representations of the characters defined by ISO/IEC 10646, along with all amendments and technical corrigenda as of the specified year and month.

Compiler_Mode_Macros

The following predefined macros are defined as 1 if the corresponding compiler mode is selected (Otherwise, they are undefined): __DECC_MODE_STRICT ! /STANDARD=ANSI89 __DECC_MODE_RELAXED ! /STANDARD=RELAXED __DECC_MODE_VAXC ! /STANDARD=VAXC __DECC_MODE_COMMON ! /STANDARD=COMMON __STDC__ ! /STANDARD=ANSI89, /STANDARD=RELAXED __STDC_VERSION__ ! /STANDARD=ISOC94 __MS ! /STANDARD=MS

Floating_Point_Macros

HP C automatically defines the following predefined macros pertaining to the format of floating-point variables. You can use them to identify the format with which you are compiling your program: __D_FLOAT __G_FLOAT __IEEE_FLOAT _IEEE_FP __X_FLOAT

RTL_Standards_Macros

HP C defines the following macros that you can explicitly define (using the /DEFINE qualifier or the #define preprocessor directive) to control which HP C RTL functions are declared in header files and to obtain standards conformance checking: _XOPEN_SOURCE_EXTENDED _XOPEN_SOURCE _POSIX_C_SOURCE _ANSI_C_SOURCE _VMS_V6_SOURCE _DECC_V4_SOURCE __BSD44_CURSES __VMS_CURSES _SOCKADDR_LEN

__HIDE_FORBIDDEN_NAMES

The ANSI C standard specifies exactly what identifiers in the normal name space are declared by the standard header files. A compiler is not free to declare additional identifiers in a header file unless the identifiers follow defined rules (the identifier must begin with an underscore followed by an uppercase letter or another underscore). When you compile with HP C using any values of /STANDARD that set strict C standard conformance (ANSI89, MIA, C99, and LATEST), versions of the standard header files are included that hide many identifiers that do not follow the rules. The header file <stdio.h>, for example, hides the definition of the macro TRUE. The compiler accomplishes this by predefining the macro __HIDE_FORBIDDEN_NAMES for the above-mentioned /STANDARD values. You can use the command line qualifier /UNDEFINE="__HIDE_FORBIDDEN_NAMES" to prevent the compiler from predefining this macro, thus including macro definitions of the forbidden names. The header files are modified to only define additional VAX C names if __HIDE_FORBIDDEN_NAMES is undefined. For example, <stdio.h> might contain the following: #ifndef __HIDE_FORBIDDEN_NAMES #define TRUE 1 #endif

CC$gfloat

When you compile using the /G_FLOAT qualifier, CC$gfloat is defined as 1. When you compile without the /G_FLOAT qualifier, CC$gfloat is defined as 0. The CC$gfloat macro is provided for compatiblity with VAX C. The __G_FLOAT predefined macro should be used instead.

__DATE__

The __DATE__ macro evaluates to a string specifying the date on which the compilation started. The string presents the date in the form "Mmm dd yyyy" The names of the months are those generated by the asctime library function. The first d is a space if dd is less than 10. Example: printf("%s",__DATE__);

__FILE__

The __FILE__ macro evaluates to a string literal specifying the file specification of the current source file. Example: printf("file %s", __FILE__);

__LINE__

The __LINE__ macro evaluates to a decimal constant specifying the number of the line in the source file containing the macro reference. Example: printf("At line %d in file %s", __LINE__, __FILE__);

__TIME__

The __TIME__ macro evaluates to a string specifying the time that the compilation started. The time has the following format: hh:mm:ss Example: printf("%s", __TIME__); The value of this macro remains constant throughout the translation unit.