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cgcccompilationc-preprocessorflags

Ignoring or redefining GCC Standard Predefined Macros

Is it possible to tell GCC to compile the source code, and ignore macros like __FILE__, __LINE__ , etc, etc, or redefine them to expand into let's say - an empty string?

Solution

  • As with any macro you can just use:

    #undef __LINE__
#undef __FILE__

    and then you can redefine them.

    You can also pass -U macroname to undef a macro name and -D macroname=definition to define a macro name to the gcc options.

    Note that, as indicated in another answer, undefining or redefining __LINE__ or __FILE__ in C invokes undefined behavior.