ILE C/C++ Compiler Reference

#ifdef

The ifdef directive checks for the existence of macro definitions.

If the identifier specified is defined as a macro, the tokens that immediately follow the condition are passed on to the compiler after a newline.

The ifdef directive has the form:

                         .----------------.
                         V                |
>>-#--ifdef--identifier----token_sequence-+--------------------><
 
 

The following example defines MAX_LEN to be 75 if EXTENDED is defined for the preprocessor. Otherwise, MAX_LEN is defined to be 50.

#ifdef EXTENDED
#   define MAX_LEN 75
#else
#   define MAX_LEN 50
#endif


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