#undef
(Preprocessor Statement)
Makes a symbol constant defined with #define or macro definition invalid.
#undef {<Symbol constant>|<Macro name>}
This statement makes a symbol constant defined with #define or macro definition invalid in the program after this #undef. Designate only the macro name for a macro with an argument.
#UNDEF NAME
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'Makes NAME defined with a symbol definition or
'macro definition in the #DEFINE statement invalid.
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