Hi, I've written my own archive, which works fine until I try serialising a boost::shared_ptr<X>, in which case I get: undefined reference to `boost::archive::detail::archive_pointer_oserializerboost::archive::boost_oarchive::~archive_pointer_oserializer(). (boost::archive::boost_oarchive is my archive class, in case this causes confusion). I'm on gcc4.1.2, ceontos4 x86_64. I'm linking to libboost_serialization-gcc41-mt-1_35.so also. I've hit a bit of a brick wall here so any help would be greatly appreciated. I've searched around but can't seem to find any relevant posts on this subject. cheers A _________________________________________________________________ Get all your favourite content with the slick new MSN Toolbar - FREE http://clk.atdmt.com/UKM/go/111354027/direct/01/