#include <boost/serialization/nvp.hpp>
#include <boost/archive/xml_oarchive.hpp>
#include <iostream>

using namespace std;
using namespace boost::archive;

class Nested {
public:
    explicit Nested()
    : mC()
    { }

    explicit Nested(char c)
    : mC(c)
    { }

private:
    friend class boost::serialization::access;

    template<class Archive>
    void serialize(Archive& ar, const unsigned int)
    {
        using boost::serialization::make_nvp;
        ar & make_nvp("c", mC);
    };

private:
    char mC;
};

BOOST_CLASS_VERSION(Nested, 0);

int main()
{
    Nested n('c');

    {
        using boost::serialization::make_nvp;
        xml_oarchive ar(cout);
        ar << make_nvp("Nested", n);
    }

    return 0;
}