 Cx51 User's Guide | |
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Cx51 User's Guide
Cx51 Introduction Compiling Programs Language Extensions Preprocessor Header Files
How #include Works Including Files Once Only Macros Simple Macros Complex Macros Macro Operators Stringize (#) Token Pasting (##) Defined Predefined Macros Undefining and Redefining Macro Caveats Preprocessor Directives Conditional Compilation #define #elif #else #endif #error #if #ifdef #ifndef #include #line #message #pragma #undef #warning Advanced Programming 8051 Derivatives Error Messages Library Reference Appendix#undef
The #undef directive un-defines a macro name.
#undef macro-name
#undef causes the previously defined macro macro-name to no longer be defined as a macro. If macro-name is not defined, #undef is ignored. Predefined macros are not affected by #undef.
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