template <T> void tvision_obj_from_magic(T *dest, SV *objref, int flags) {
  struct tvision_info* tinfo= tvision_info_from_magic(objref, flags);
  T typed= tinfo->tobj? dynamic_cast<T>(tinfo->tobj) : NULL;
  if ((flags & OR_DIE) && !typed) croak("Wrong type of object");
  *dest= typed;
}