Directives to the Preprocessor

 

For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.

A "directive" instructs the C preprocessor to perform a specific action on the text of the program before compilation. Preprocessor directives are fully described in the Preprocessor Reference. This example uses the preprocessor directive #define:

#define MAX 100  

This statement tells the compiler to replace each occurrence of MAX by 100 before compilation. The C compiler preprocessor directives are:

#define#endif#ifdef#line
#elif#error#ifndef#pragma
#else#if#include#undef

Source Files and Source Programs

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