1  extern void abort (void);
       2  
       3  struct A
       4  {
       5    int i;
       6  };
       7  struct B
       8  {
       9    struct A a;
      10    int j;
      11  };
      12  
      13  static void
      14  foo (struct B *p)
      15  {
      16    ((struct A *)p)->i = 1;
      17  }
      18  
      19  int main()
      20  {
      21    struct A a;
      22    a.i = 0;
      23    foo ((struct B *)&a);
      24    if (a.i != 1)
      25      abort ();
      26    return 0;
      27  }
      28