void must_not_delete_cpp_object(SV* perl_obj, bool must_not_delete) {
	HV* hidden_hash;
	IV can_delete;
	SV** can_delete_sv;

	hidden_hash = get_hidden_hash(perl_obj);
	can_delete_sv = hv_fetch(hidden_hash, "_can_delete", 11, 0);
	can_delete = must_not_delete ? 0 : 1;
	sv_setiv(*can_delete_sv, can_delete);
	hv_store(hidden_hash, "_can_delete", 11, *can_delete_sv, 0);
}