Preprocessors: #undef

Applies To: C++Builder 1 or higher
Category: C++ Language

The #undef directive undefines a macro previously defined using the #define preprocessor. It uses the following general form:

 

#undef macro

 

The #undef directive is usually used to define the same macro two times. For example:

 

#define VALUE 100

int x = VALUE;

 

#undef VALUE

#define VALUE 200

int y = VALUE;

 

In the previous example, x will contain the value 100 and y, 200.

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