Re: [Boost-users] boost::serialization throwing "input stream error" on base class ptr XML serialization

Jari wrote:

//Why do these need to be wrappers?? namespace boost { namespace serialization { template<> struct is_wrapper : mpl::true_ {}; template<> struct is_wrapper<A> : mpl::true_ {}; template<> struct is_wrapper<const A> : mpl::true_ {}; } }

I don't know why the above is there. It should be taken out

BOOST_SERIALIZATION_ASSUME_ABSTRACT(A); BOOST_CLASS_EXPORT(B) BOOST_CLASS_EXPORT(C)

int main(int argc, char** argv) { //A* a = new A(); A* b = new B(); A* c = new C(); //A* a1 = nullptr; A* a2 = nullptr; A* a3 = nullptr;

ostringstream ostream; xml_oarchive oarchive(ostream);

oarchive /*<< BOOST_SERIALIZATION_NVP(a)*/ << BOOST_SERIALIZATION_NVP(b) << BOOST_SERIALIZATION_NVP(c);

istringstream istream(ostream.str()); xml_iarchive iarchive(istream);

iarchive /*>> BOOST_SERIALIZATION_NVP(a1)*/ >> BOOST_SERIALIZATION_NVP(a2) >> BOOST_SERIALIZATION_NVP(a3);

//delete a; delete b; delete c; //delete a1; delete a2; delete a3; }

The problem is: oarchive << BOOST_SERIALIZATION_NVP(a) creates an item data </a> iarchive >> BOOST_SERIALIZATION_NVP(a1) expects an item data </a1> The serialization library verifies that the name used to save is the name used to load because that's usually a bug. If you want the above to work you'l ahve to use: use the following instead so that the tag is always a oarchive << make_nvp("a", a) creates an item data </a> iarchive >> make_nvp("a", a1) expects an item data </a1>