B.38 Macro Replacement-Predefined Macro Names (§3.8.3)

In addition to the predefined macro names defined in the Standard, the DEC C compiler defines other preprocessor macros for various identification purposes. When the compiler is invoked, the appropriate identification macros are defined depending on the operating system, architecture, language, compiler mode, and other environment variables. You can reference these macros in #ifdef preprocessor directives to isolate code that applies to a particular environment.

Each DEC C platform can have additional predefined macros. See your platform-specific DEC C documentation for more information.

Table B-1 shows the predefined macro names for Digital UNIX.

Table B-1 Digital UNIX Predefined Macro Names

Table B-2 shows the predefined macro names for OpenVMS VAX and Alpha systems. All forms are defined unless strict ANSI mode is in effect, in which case only the new spellings are defined.

Table B-2 OpenVMS VAX and Alpha Predefined Macro Names

You can explicitly define the macros in Table B-3 to control which C library routines are declared in header files and to obtain standards conformance checking. To define these macros use one of the following:

• -D flag (Digital UNIX)

• /DEFINE qualifier (OpenVMS)

• #define preprocessor directive

Table B-3 Library Routine Standards Conformance Macros-All platforms