1  struct foo {
       2    char a[3];
       3    char b;
       4    char c;
       5  };
       6  
       7  struct foo bs;
       8  int x;
       9  char y[3];
      10  
      11  void bar(void)
      12  {
      13      memcpy(bs.a, y, 3);
      14      bs.a[1] = ((x ? &bs.b : &bs.c) - (char *)&bs) - 2;
      15  }