overload1.c

this is a gcc file, you can download it and learn its usetility, for further detail please look at t

// Build don't link:

// Copyright (C) 1999 Free Software Foundation

// by Alexandre Oliva <[e-mail]>
// Based on bug report by JDonner <[e-mail]>

struct foo {
  static int bar(); // ERROR - candidate
  void bar(int); // ERROR - candidate
};

/* gcc emits a hard error without -pedantic, and a warning with
   -pedantic, even in bad1.  */
int (*ok1)() = foo::bar;
void (foo::*bad1)(int) = foo::bar; // ERROR - missing &

int (*ok2)() = &foo::bar; // ok
void (*bad2)(int) = foo::bar; // ERROR - overload resolution fails

void (foo::*ok3)(int) = &foo::bar; // ok
int (foo::*bad3)() = foo::bar; // ERROR - overload resolution fails