C - Conditional Compilation2
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Conditional Compilation ...
- e.g, 1
To make sure that the contents of file hdr.h are included only once, the contents of the file are surrounded with a condition like this
#if !defined(HDR) #define HDR // contents of hdr.h go here #endif
- e.g, 2
#ifdef identifier is equ #if defined identifier #ifndef is equ #if !defined identifier