MessageActually, the export.hpp has to come after any *archive.hpp due to the "trick" used to instantiate the appropriate code. On some compilers, one can get multiple symbol errors. I think the only way to handle this is to be sure its included at most once or tweak the linker switches to override the error. Robert Ramey "Eric" <eric-public@omnicurious.com> wrote in message news:001601c564d9$35709a60$0a00a8c0@FASTBRICK... Thanks Robert. This partially worked... Your comment about putting the BOOST_CLASS_EXPORT macro into the header keyed me into something. I am using the BOOST_CLASS_EXPORT(derived) macro, but I've been placing them into the source (cpp) file instead of the header (h) file. With my system, when I put BOOST_CLASS_EXPORT(derived) into the header file, I get a multiply-defined error at link time (the offending code is boost::archive::detail::guid_initializer<class,...> since the header is included multiple times when I use the class. As a test, I setup a sandbox with a stripped down system and was able to get it to work when I put the BOOST_CLASS_EXPORT in the header, but not when it is in the cpp file. Q: Why does the location of the BOOST_CLASS_EXPORT matter? Is it doing order-depended initialization upon bringing up the system? Q: How do I avoid the mutiple defined error in the linker? Thanks again for your help and the library :) -Eric ------------------------------------------------------------------------------ _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users