1  struct S
       2  {
       3    unsigned int iu;
       4  };
       5  
       6  union U
       7  {
       8    struct S s;
       9    signed int is;
      10  };
      11  
      12  extern signed int bar ();
      13  
      14  struct S foo (void)
      15  {
      16    union U u;
      17  
      18    u.is = bar ();
      19    return u.s;
      20  }