1  extern int foo(void);
       2  typedef int (*func_p) (void);
       3  extern func_p foo_ptr;
       4  
       5  void
       6  check_foo (void)
       7  {
       8    if (foo_ptr != foo)
       9      __builtin_abort ();
      10    if (foo_ptr() != 1)
      11      __builtin_abort ();
      12    if (foo() != 1)
      13      __builtin_abort ();
      14  }