1  f()
       2  {
       3    unsigned b = 0;
       4  
       5    if (b > ~0U)
       6      b = ~0U;
       7  
       8    return b;
       9  }
      10  main()
      11  {
      12    if (f()!=0)
      13      abort();
      14    exit (0);
      15  }