1  extern void abort (void);
       2  extern void exit (int);
       3  struct s { unsigned char a[256]; };
       4  union u { struct { struct s b; int c; } d; struct { int c; struct s b; } e; };
       5  static union u v;
       6  static union u v0;
       7  static struct s *p = &v.d.b;
       8  static struct s *q = &v.e.b;
       9  
      10  static inline struct s rp (void) { return *p; }
      11  static inline struct s rq (void) { return *q; }
      12  static void pq (void) { *p = rq(); }
      13  static void qp (void) { *q = rp(); }
      14  
      15  static void
      16  init (struct s *sp)
      17  {
      18    int i;
      19    for (i = 0; i < 256; i++)
      20      sp->a[i] = i;
      21  }
      22  
      23  static void
      24  check (struct s *sp)
      25  {
      26    int i;
      27    for (i = 0; i < 256; i++)
      28      if (sp->a[i] != i)
      29        abort ();
      30  }
      31  
      32  void
      33  main_test (void)
      34  {
      35    v = v0;
      36    init (p);
      37    qp ();
      38    check (q);
      39    v = v0;
      40    init (q);
      41    pq ();
      42    check (p);
      43    exit (0);
      44  }