1  double glob_dbl;
       2  
       3  f (pdbl, value)
       4       double *pdbl;
       5       double value;
       6  {
       7    if (pdbl == 0)
       8      pdbl = &glob_dbl;
       9  
      10    *pdbl = value;
      11  }
      12  
      13  main ()
      14  {
      15    f ((void *) 0, 55.1);
      16  
      17    if (glob_dbl != 55.1)
      18      abort ();
      19    exit (0);
      20  }