COHERENT manpages

This page displays the COHERENT manpage for #ifndef [Include code conditionally].

List of available manpages
Index

#ifndef -- Preprocessing Directive

Include code conditionally

The  preprocessing directive  #ifndef  checks whether  identifier has  been
defined as  a macro name.  If  identifier has not been  defined as a macro,
then the  preprocessor includes  group within the  program, up to  the next
#elif,  #else,  or  #endif  directive.   If  identifier has  been  defined,
however, then group is skipped.

An #ifndef directive can be followed  by any number of #elif directives, by
one #else directive, and by one #elif directive.

See Also

#elif,
#else,
#endif,
#if,
#ifndef,
C preprocessor,
defined
ANSI Standard, §6.8.1