only.c

extern /*@only@*/ int *glob;
 
/*@only@*/ int *
  f (/*@only@*/ int *x, int *y,
     int *z)
  /*@globals int *glob;@*/
{
  int *m = (int *)
    malloc (sizeof (int));
  
  glob = y;
  free (x);
  *m = *x;
  return z;
}