IFDEF

Begins block that will be compiled only if given macro is defined.

Syntax

IFDEF Name [identifier]

Description

This directive begins block of code that will be allowed to pass to the compiler by the preprocessor only if macro with given name is already defined (no matter what content it has or whether it is empty). Otherwise lines below this will be skipped until corresponding ENDIF directive.

Example

DEFINE OLD_AND_DEPRECATED

IFDEF OLD_AND_DEPRECATED
  ERROR "You shouldn't define this!"
ENDIF