1  typedef enum { C = 1, D = 2 } B;
       2  extern void abort (void);
       3  
       4  struct S
       5  {
       6    B __attribute__ ((mode (byte))) a;
       7    B __attribute__ ((mode (byte))) b;
       8  };
       9  
      10  void
      11  foo (struct S *x)
      12  {
      13    if (x->a != C || x->b != D)
      14      abort ();
      15  }
      16  
      17  int
      18  main (void)
      19  {
      20    struct S s;
      21    s.a = C;
      22    s.b = D;
      23    foo (&s);
      24    return 0;
      25  }