Robert, Thanks for the example; it helped clear up some uncertainty about the template arguments in the derived class. Regarding save_override, I see where specialized versions for the different trait types are defined in basic_xml_oarchive.ipp. I also see that save_override is called from the operator<< redefinition in interface_oarchive.hpp. What I'm missing is the link between serializing a user-defined class object and the traits of that object. template<class Archive> BOOST_ARCHIVE_OR_WARCHIVE_DECL(void) basic_xml_oarchive<Archive>::save_override(const version_type & t, int) { int i = t.t; // extra .t is for borland write_attribute(VERSION(), i); } This function already displays a version attribute in the XML. How do I make sure this is called for every element? I'm sorry, but I can't figure out how to modify chain of control to force output of class traits. Starting in oserializer.hpp, boost::archive::save<Archive,T> calls static save_non_pointer_type<Archive, T>::invoke calls serialize_adl calls boost::serialization::serialize<Archive, T> calls access::serialize calls myClass::serialize<Archive> (Archive& ar, unsigned int version) There is also a function oserializer<Archive,T>::save_object_data that calls serialize_adl, but I can't find anything that calls it. The struct save_non_pointer_type<Archive, T> in oserializer.hpp may be the key, but I'm not sure how it works. In oserializer.hpp, struct save_non_pointer_type<Archive,T>::save_standard::invoke calls Archive::save_object, but I do not see an implementation of the function anywhere: $ find /usr/include/boost -type f -exec grep -H save_object {} \;| grep -v save_object_ | more /usr/include/boost/archive/polymorphic_oarchive.hpp: virtual void save_object( /usr/include/boost/archive/detail/oserializer.hpp: ar.save_object(& t, oserializer<Archive, T>::instantiate()); /usr/include/boost/archive/detail/basic_oarchive.hpp: void save_object( /usr/include/boost/archive/detail/polymorphic_oarchive_impl.hpp: virtual void save_object( /usr/include/boost/archive/detail/polymorphic_oarchive_impl.hpp: ArchiveImplementation::save_object(x, bos); I'd appreciate any suggestions. Am I even looking in the right place? Thanks in advance, Bill -----Original Message----- From: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Robert Ramey Sent: Wednesday, July 26, 2006 12:14 PM To: boost-users@lists.boost.org Subject: Re: [Boost-users] XML Serialization Traits Question "William Bardon" <wbardon@cabcds.org> wrote in message news:C73E689C9FCF884B9A550ECFADA0721C087D3E@exchange.cab-cds.org... I have read both the Boost Serialization online documentation and the archives of the Boost-Users mailing list looking for guidance, but I haven't found anything relevant. I see how to use BOOST_CLASS_TRACKING and BOOST_CLASS_IMPLEMENTATION to remove version tracking attributes from the XML tags. Usage of these macros does a lot more than remove attributes from the tags. I want to go in the opposite direction. I notice that the class_id and version attributes only appear the first time an object of a particular class is serialized. I want to force the version attribute to appear in every object's attribute list. Do I need to derive a custom archive to do this? yes I have looked at the source code for serialization, but I have trouble plowing through all of the macros, template expansions, and overloaded functions to locate the specific part that controls whether class traits are stored as attributes in a particular XML tag. I sympathize - its hard to follow. And I wrote it. Here are some hints: a) look at demo_fast_archive.cpp to see a model of how one can derive from an existing archive. b) You'll want to derive from xml_oarchive_impl<...> to create my_xml_oarchive c) add a "save_override" function to my_xml_oarchive which replaces the "save_override" function in basic_xml_oarchive.ipp. Implement this using functions defined basic_xml_oarchive.ipp Good luck - Robert Ramey Thanks in advance, Bill _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users