1  extern int bar(void);
       2  typedef int (*func_p) (void);
       3  extern func_p get_bar (void);
       4  
       5  void
       6  check_bar (void)
       7  {
       8    func_p bar_ptr = get_bar ();
       9    if (bar_ptr != bar)
      10      __builtin_abort ();
      11    if (bar_ptr() != -1)
      12      __builtin_abort ();
      13    if (bar() != -1)
      14      __builtin_abort ();
      15  }