GNU Info

(gcc-295.info)Function Names

---

Next: Return Address Prev: Incomplete Enums Up: C Extensions

---

Enter node , (file) or (file)node

Function Names as Strings
=========================

   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__'.