Hi Robert and everyone, Thank you for explaining to me about BOOST_STRONGTYPE. I'll let you know how that goes for me. And thank you for being so patient and trying to help me get serialization working in my program. In the meantime, I'm experiencing a much simpler problem. Although I can serialize classes of the form boost::shared_ptr<T>, where T is a class I've defined, I get compilation errors if I try to serialize a boost::shared_ptr<int>. How can I resolve this? Code snippet: ----------------------------------------------- #include <iostream> #include <fstream> #include <boost/shared_ptr.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/utility.hpp> #include <boost/serialization/shared_ptr.hpp> int main() { std::ofstream ofs("archive"); boost::archive::text_oarchive oa(ofs); boost::shared_ptr<int> i; oa << i; return 0; } ----------------------------------------------- g++ output: /usr/include/boost/serialization/shared_ptr.hpp: In function `void boost::serialization::serialize(Archive&, boost::shared_ptr<U>&, unsigned int) [with Archive = boost::archive::text_oarchive, T = int]': /usr/include/boost/serialization/serialization.hpp:140: instantiated from `void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/archive/detail/oserializer.hpp:147: instantiated from `void boost::archive::detail::oserializer<Archive, T>::save_object_data(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/mpl/if.hpp:67: instantiated from here /usr/include/boost/serialization/shared_ptr.hpp:227: error: incomplete type ` boost::STATIC_ASSERTION_FAILURE<false>' does not have member `value' /usr/include/boost/serialization/shared_ptr.hpp: In function `void boost::serialization::save(Archive&, const boost::shared_ptr<U>&, unsigned int) [with Archive = boost::archive::text_oarchive, T = int]': /usr/include/boost/serialization/split_free.hpp:45: instantiated from `static void boost::serialization::free_saver<Archive, T>::invoke(Archive&, const T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/serialization/split_free.hpp:74: instantiated from `void boost::serialization::split_free(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/serialization/shared_ptr.hpp:231: instantiated from `void boost::serialization::serialize(Archive&, boost::shared_ptr<U>&, unsigned int) [with Archive = boost::archive::text_oarchive, T = int]' /usr/include/boost/serialization/serialization.hpp:140: instantiated from `void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/archive/detail/oserializer.hpp:147: instantiated from `void boost::archive::detail::oserializer<Archive, T>::save_object_data(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/mpl/if.hpp:67: instantiated from here /usr/include/boost/serialization/shared_ptr.hpp:183: error: incomplete type ` boost::STATIC_ASSERTION_FAILURE<false>' does not have member `value' /usr/include/boost/serialization/access.hpp: In static member function `static void boost::serialization::access::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = int]': /usr/include/boost/serialization/serialization.hpp:81: instantiated from `void boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = int]' /usr/include/boost/serialization/serialization.hpp:140: instantiated from `void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = int]' /usr/include/boost/archive/detail/oserializer.hpp:232: instantiated from `boost::archive::detail::pointer_oserializer<T, Archive>::pointer_oserializer() [with T = int, Archive = boost::archive::text_oarchive]' /usr/include/boost/archive/detail/oserializer.hpp:197: instantiated from `const boost::archive::detail::pointer_oserializer<int, boost::archive::text_oarchive> boost::archive::detail::pointer_oserializer<int, boost::archive::text_oarchive>::instance' /usr/include/boost/archive/detail/oserializer.hpp:189: instantiated from `static const boost::archive::detail::pointer_oserializer<T, Archive>& boost::archive::detail::pointer_oserializer<T, Archive>::instantiate() [with T = int, Archive = boost::archive::text_oarchive]' /usr/include/boost/archive/detail/oserializer.hpp:514: instantiated from `const boost::archive::detail::basic_pointer_oserializer& boost::archive::detail::instantiate_pointer_oserializer(Archive*, T*) [with Archive = boost::archive::text_oarchive, T = int]' /usr/include/boost/archive/detail/interface_oarchive.hpp:65: instantiated from `const boost::archive::detail::basic_pointer_oserializer* boost::archive::detail::interface_oarchive<Archive>::register_type(const T*) [with T = int, Archive = boost::archive::text_oarchive]' /usr/include/boost/archive/detail/oserializer.hpp:343: instantiated from `static const boost::archive::detail::basic_pointer_oserializer* boost::archive::detail::save_pointer_type<Archive, TPtr>::non_abstract<T>::register_type(Archive&) [with T = const int, Archive = boost::archive::text_oarchive, TPtr = const int*]' /usr/include/boost/archive/detail/oserializer.hpp:359: instantiated from `static const boost::archive::detail::basic_pointer_oserializer* boost::archive::detail::save_pointer_type<Archive, TPtr>::register_type(Archive&, T&) [with T = const int, Archive = boost::archive::text_oarchive, TPtr = const int*]' /usr/include/boost/archive/detail/oserializer.hpp:459: instantiated from `static void boost::archive::detail::save_pointer_type<Archive, TPtr>::invoke(Archive&, TPtr) [with Archive = boost::archive::text_oarchive, TPtr = const int*]' /usr/include/boost/archive/detail/oserializer.hpp:535: instantiated from `void boost::archive::save(Archive&, const T&) [with Archive = boost::archive::text_oarchive, T = const int*]' /usr/include/boost/archive/basic_text_oarchive.hpp:78: instantiated from `void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) [with T = const int* const, Archive = boost::archive::text_oarchive]' /usr/include/boost/archive/detail/interface_oarchive.hpp:85: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = const int* const, Archive = boost::archive::text_oarchive]' /usr/include/boost/serialization/nvp.hpp:77: instantiated from `void boost::serialization::nvp<T>::save(Archivex&, unsigned int) const [with Archivex = boost::archive::text_oarchive, T = const int*]' /usr/include/boost/serialization/access.hpp:93: instantiated from `static void boost::serialization::access::member_save(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = const boost::serialization::nvp<const int*>]' /usr/include/boost/serialization/split_member.hpp:43: instantiated from `static void boost::serialization::detail::member_saver<Archive, T>::invoke(Archive&, const T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::serialization::nvp<const int*>]' /usr/include/boost/serialization/split_member.hpp:69: instantiated from `void boost::serialization::split_member(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::serialization::nvp<const int*>]' /usr/include/boost/serialization/nvp.hpp:87: instantiated from `void boost::serialization::nvp<T>::serialize(Archive&, unsigned int) [with Archive = boost::archive::text_oarchive, T = const int*]' /usr/include/boost/serialization/access.hpp:109: instantiated from `static void boost::serialization::access::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::serialization::nvp<const int*>]' /usr/include/boost/serialization/serialization.hpp:81: instantiated from `void boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::serialization::nvp<const int*>]' /usr/include/boost/serialization/serialization.hpp:140: instantiated from `void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::serialization::nvp<const int*>]' /usr/include/boost/archive/detail/oserializer.hpp:252: instantiated from `static void boost::archive::detail::save_non_pointer_type<Archive, T>::save_only::invoke(Archive&, const T&) [with Archive = boost::archive::text_oarchive, T = boost::serialization::nvp<const int*>]' /usr/include/boost/archive/detail/oserializer.hpp:321: instantiated from `static void boost::archive::detail::save_non_pointer_type<Archive, T>::invoke(Archive&, const T&) [with Archive = boost::archive::text_oarchive, T = boost::serialization::nvp<const int*>]' /usr/include/boost/archive/detail/oserializer.hpp:535: instantiated from `void boost::archive::save(Archive&, const T&) [with Archive = boost::archive::text_oarchive, T = boost::serialization::nvp<const int*>]' /usr/include/boost/archive/basic_text_oarchive.hpp:78: instantiated from `void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) [with T = const boost::serialization::nvp<const int*>, Archive = boost::archive::text_oarchive]' /usr/include/boost/archive/detail/interface_oarchive.hpp:85: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = const boost::serialization::nvp<const int*>, Archive = boost::archive::text_oarchive]' /usr/include/boost/serialization/shared_ptr.hpp:185: instantiated from `void boost::serialization::save(Archive&, const boost::shared_ptr<U>&, unsigned int) [with Archive = boost::archive::text_oarchive, T = int]' /usr/include/boost/serialization/split_free.hpp:45: instantiated from `static void boost::serialization::free_saver<Archive, T>::invoke(Archive&, const T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/serialization/split_free.hpp:74: instantiated from `void boost::serialization::split_free(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/serialization/shared_ptr.hpp:231: instantiated from `void boost::serialization::serialize(Archive&, boost::shared_ptr<U>&, unsigned int) [with Archive = boost::archive::text_oarchive, T = int]' /usr/include/boost/serialization/serialization.hpp:140: instantiated from `void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/archive/detail/oserializer.hpp:147: instantiated from `void boost::archive::detail::oserializer<Archive, T>::save_object_data(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::text_oarchive, T = boost::shared_ptr<int>]' /usr/include/boost/mpl/if.hpp:67: instantiated from here /usr/include/boost/serialization/access.hpp:109: error: request for member ` serialize' in `t', which is of non-aggregate type `int' ----------------------------------------------- Thanks again for being so helpful! Joseph -- http://www.cs.nyu.edu/~turian/