Treating __func__ as a string literal instead of a predefined identifier

Question

I am using gcc to compile C99 code. I want to write a macro which will return a string containing the function name and line number.

This is what I have:

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Answer 1

Remark that, "__func__ is not a function so it cannot be called; in fact, it is a predefined identifier that points to a string that is the name of the function, and is only valid inside the scope of a function." - Jonathan.

The following is what you are looking for:

#define TO_STR_A( A ) #A
#define TO_STR( A ) TO_STR_A( A )
#define INFO_MSG TO_STR( __LINE__ ) ":" __FILE__

char buff[ 256 ] = { 0 };

sprintf( buff, "Something bad happened here, %s in function %s().", INFO_MSG, __func__ );
printf( "INFO: %s\n", buff );

... note that a call to __func__ can be made inside the function itself. See this.