1  int
       2  test (arg)
       3       int arg;
       4  {
       5    if (arg > 0 || arg == 0)
       6      return 0;
       7    return -1;
       8  }
       9  
      10  main ()
      11  {
      12    if (test (0) != 0)
      13      abort ();
      14    if (test (-1) != -1)
      15      abort ();
      16    exit (0);
      17  }