#else -- Preprocessing Directive

Include code conditionally

The  preprocessing directive  #else  conditionally includes  code within  a
program.  It is preceded by one  of the directives #if, #ifdef, or #ifndef,
and  may also  be  preceded by  any  number of  #elif  directives.  If  the
conditional  expressions  of all  preceding  directives  evaluate to  false
(i.e., to zero),  then the code introduced by #else  is included within the
program, up to the #endif directive.

A  #if, #ifdef,  or #ifndef  directive can  be followed  by only  one #else
directive.

See Also

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

© 2012 by Stephen A. Ness