1  foo (a)
       2  {
       3    int bar = 0;
       4  
       5    return (unsigned) (a - 1) <= (unsigned) bar;
       6  }
       7  
       8  main ()
       9  {
      10    if (foo (-1))
      11      puts ("The largest possible unsigned <= 0 on this machine...");
      12  }