Hi all - I've got a class hierarchy that can already be serialized into text or binary archives. I'm explicitly instantiating the template functions for serialize and/or load/save. I'm trying to add the capability to have boost mpi perform the serialization through send/recv/broadcast. I've added explicit instantiations for the boost::mpi::packed_iarchive and packed_oarchive. My code compiles, but at the end I get a bunch of undefined references for serialize<boost::mpi::detail::mpi_datatype_oarchive>. I can add the explicit instantiations for this oarchive, and this seems to fix my linking issue, but this seems broken, i.e. I should not have to deal with anything in a boost::detail namespace? Is there another suggestion for how to get this to work? Thanks, Brian