GNU CC predefines two string variables to be the name of the current function.
The variable __FUNCTION__
is the name of the function as it appears
in the source. The variable __PRETTY_FUNCTION__
is the name of
the function pretty printed in a language specific fashion.
These names are always the same in a C function, but in a C++ function they may be different. For example, this program:
extern "C" { extern int printf (char *, ...); } class a { public: sub (int i) { printf ("__FUNCTION__ = %s\n", __FUNCTION__); printf ("__PRETTY_FUNCTION__ = %s\n", __PRETTY_FUNCTION__); } }; int main (void) { a ax; ax.sub (0); return 0; }
gives this output:
__FUNCTION__ = sub __PRETTY_FUNCTION__ = int a::sub (int)
These names are not macros: they are predefined string variables.
For example, `#ifdef __FUNCTION__' does not have any special
meaning inside a function, since the preprocessor does not do anything
special with the identifier __FUNCTION__
.