I noticed in serializations basic_iarchive that when you're not building for debug the next line here (317 in basic_iarchive.cpp) has a warning for unused variable new_cid. The BOOST_ASSERT is instantiated as ((void)0) so new_cid really isn't used. Could the register_type call be moved into the assert? class_id_type new_cid = register_type(bpis_ptr->get_basic_serializer()); int i = cid; cobject_id_vector[i].bpis_ptr = bpis_ptr; BOOST_ASSERT(new_cid == cid); Something like: BOOST_ASSERT(register_type(bpis_ptr->get_basic_serializer()) == cid); Then the new_cid variable wouldn't be needed and the call to register_type would disappear with the BOOST_ASSERT if you aren't building for debug. Or, does the call to register_type have an important side effect that is required? Patrick