1  extern void abort ();
       2  
       3  int f(int x)
       4  {
       5    return (x >> (sizeof (x) * __CHAR_BIT__ - 1)) ? -1 : 1;
       6  }
       7  
       8  volatile int one = 1;
       9  int main (void)
      10  {
      11    /* Test that the function above returns different values for
      12       different signs.  */
      13    if (f(one) == f(-one))
      14      abort ();
      15    return 0;
      16  }
      17