Hi, I'm currently trying to polymorphically serialize a class without using RTTI. I'm doing this currently in a file called StaticText.hpp: #ifndef RS_GUI_WIDGETS_STATICTEXT_HPP #define RS_GUI_WIDGETS_STATICTEXT_HPP #include <boost/scoped_ptr.hpp> #include <boost/serialization/access.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/string.hpp> #include <boost/serialization/extended_type_info_no_rtti.hpp> #include <boost/serialization/export.hpp> #include <rs/gui/widgets/Widget.hpp> #include <rs/gui/Text.hpp> namespace rs { class StaticText : public Widget { public: StaticText( std::string const& text ); void Update(); void Render( RenderSystem& renderer, Camera& camera ); char const* get_key() const; private: StaticText() {} template< class Archive > void serialize( Archive& archive, unsigned int version ) { archive & boost::serialization::base_object<Widget>( *this ); std::string text; archive & text; m_text.reset( new Text( text ) ); } boost::scoped_ptr<Text> m_text; friend class boost::serialization::access; }; } BOOST_CLASS_TYPE_INFO( rs::StaticText, extended_type_info_no_rtti<rs::StaticText> ) BOOST_CLASS_EXPORT( rs::StaticText ) #endif // RS_GUI_WIDGETS_STATICTEXT_HPP When I compile this into a LIB first, and then link the lib into an EXE, the linker says this (Visual Studio 2008): *gui.lib(StaticText.obj) : error LNK2005: "public: static struct boost::archive::detail::guid_initializer<class rs::StaticText> const & const boost::archive::detail::init_guid<class rs::StaticText>::guid_initializer" (?guid_initializer@?$init_guid@VStaticText@rs@@@detail@archive@boost@ @2ABU?$guid_initializer@VStaticText@rs@@@234@B) already defined in main.obj* * * If I move the 2 macro calls into the StaticText.cpp file, everything compiles/links just fine but I end up getting an exception thrown at runtime that says "unregistered void cast".