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, like the following 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;
}
The program, then, gives the
following 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__. 0