Topic       : C-Language Documentation
Author      : John Kormylo
Version     : C.HYP 1.0
Subject     : Documentation/C-Language
Nodes       : 233
Index Size  : 6362
HCP-Version : 3
Compiled on : Atari
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@lang       : en
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View Ref-File[ #if ]

  #if 'logical expression'

where 'logical expression' can use any of the Logical Operators
plus:

  defined('macro')   /* TRUE if 'macro' name is defined */

If the logical expression is TRUE (!0), then nothing happens.
If the logical expression is FALSE (0), then compilations stops until
the next '#else' '#elif' or '#endif' directive.

Example:

  #if defined(__PUREC__) && __PUREC__ > 1
  ...
  #endif

See also Preprocessor, #ifdef and #ifndef.