Hi all, First problem: -------------- i have this warning. "...... boost/mpl/print.hpp:55: warning: comparison between signed and unsigned integer expressions" Second problem: --------------- I want to serialize a template derivate class like this: //////////////////////////// class Base { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive &, const unsigned int ) { } }; template<typenmame T> class Child: public Base { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int ) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Base); } }; BOOST_CLASS_EXPORT_GUID(Child<int>, "Child")//don't work /////////////////////////// The macro "BOOST_CLASS_EXPORT_GUID" don't work with template class. Is there a way to do this ? Thank you, Regards, Damien.