#include <fstream>
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/serialization/export.hpp>

struct Base
{
    Base() : base(42) { }
    virtual ~Base() { }
    int base;

    template<class Archive>
    void serialize(Archive & ar, const unsigned int version)
    {
        ar & base;
    }
};

struct Derived : Base
{
    Derived() { }
    Derived(int n) : size(n)
    { 
        while(--n > 0) derived[n] = n; 
    }
    int size;
    int derived[0];

    template<class Archive>
    void serialize(Archive & ar, const unsigned int version)
    {
        ar & boost::serialization::base_object<Base>(*this);
        ar & size;
        for(int i = 0; i < size; ++i) ar & derived[i];
    }
};

BOOST_CLASS_EXPORT_GUID(Derived, "Derived")

int main() {
    std::ofstream ofs("filename");
    
    Base *x = new(new unsigned char[sizeof(Derived) + 42 * sizeof(int)]) Derived(42);
    {
        boost::archive::text_oarchive oa(ofs);
        oa << x;
    }
    x->~Base();
    delete[] reinterpret_cast<unsigned char*>(x);
    
    // obviously this will fail
    Base *y;
    {
        std::ifstream ifs("filename");
        boost::archive::text_iarchive ia(ifs);
        // any possibility to specify the amount of memory needed to create y?
        // unfortunatly i have found none
        ia >> y;
    }
    return 0;
}