Shows the given error message and renders the program ill-formed. Syntax #error error_message Explanation After encountering the #error directive, an implementation displays the diagnostic message error_message and renders the program ill-formed (the compilation stops). error_message can consist of several words not necessarily in quotes. References C11 standard (ISO/IEC 9899:2011): 6.10.5 Error directive (p: 174) C99 standard (ISO/IEC 9899:1999): 6.10.5 Error directive (p

The preprocessor supports text macro replacement and function-like text macro replacement. Syntax #define identifier replacement-list(optional) (1) #define identifier( parameters ) replacement-list (2) #define identifier( parameters, ... ) replacement-list (3) (since C99) #define identifier( ... ) replacement-list (4) (since C99) #undef identifier (5) Explanation #define directives The #define directives define the identifier as a macro, that is they in