1  int *ptr1 = 0, **ptr2 = &ptr1;
       2  
       3  int *identity(int *p)
       4  {
       5    return p;
       6  }
       7  
       8  void store_to_c(int *p)
       9  {
      10    *ptr2 = identity(p);
      11  }
      12  
      13  int main()
      14  {
      15    int f;
      16    store_to_c(&f);
      17    if (ptr1 != &f)
      18      __builtin_abort();
      19    return 0;
      20  }