#include <cassert>
#include <fstream>

#include <boost/serialization/serialization.hpp>
#include <boost/archive/xml_oarchive.hpp>
#include <boost/archive/xml_iarchive.hpp>
#include <boost/serialization/export.hpp>

#include <boost/serialization/nvp.hpp>

struct VBase;

struct VBase {
	virtual ~VBase() {}
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive &/*ar*/, const unsigned int /*version*/) {
    }
};

BOOST_CLASS_TRACKING(VBase, boost::serialization::track_always)


struct Mid1 : virtual VBase {
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive &ar, const unsigned int /*version*/) {
        ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(VBase);
    }
};

struct Mid2 : virtual VBase {
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive &ar, const unsigned int /*version*/) {
        ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(VBase);
    }
};

struct Sub1 : Mid1, Mid2 {
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive &ar, const unsigned int /*version*/) {
        ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Mid1);
        ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Mid2);
    }
};

struct Sub2 : Mid1, Mid2 {
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive &ar, const unsigned int /*version*/) {
        ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Mid1);
        ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Mid2);
    }
};

struct Target : Sub2 {
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive &ar, const unsigned int /*version*/) {
		ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Sub2);
	}
};

#if 0
// OK
BOOST_CLASS_EXPORT(Target)
BOOST_CLASS_EXPORT(Sub1)
#else
// NG
BOOST_CLASS_EXPORT(Sub1)
BOOST_CLASS_EXPORT(Target)
#endif

int main()
{
	// Serialize pTarget via VBase pointer.
	{
        std::ofstream ofs("outtarget.xml");
        boost::archive::xml_oarchive oa(ofs);
        assert(ofs);
		Target* pTarget = new Target;
		VBase * pVBase = pTarget;
		oa << boost::serialization::make_nvp("pVBase", pVBase);
    }
    {
        std::ifstream ifs("outtarget.xml");
        assert(ifs);
        boost::archive::xml_iarchive ia(ifs);
		VBase * pVBase;
        ia >> boost::serialization::make_nvp("pVBase", pVBase);
    }
	// Serialize pSub1 via VBase pointer.
	{
        std::ofstream ofs("outsub1.xml");
        boost::archive::xml_oarchive oa(ofs);
        assert(ofs);
		Sub1* pSub1 = new Sub1;
		VBase * pVBase = pSub1;
		oa << boost::serialization::make_nvp("pVBase", pVBase);
    }
    {
        std::ifstream ifs("outsub1.xml");
        assert(ifs);
        boost::archive::xml_iarchive ia(ifs);
		VBase * pVBase;
        ia >> boost::serialization::make_nvp("pVBase", pVBase);
    }
}