In file included from /usr/include/c++/4.4/bits/stl_algobase.h:66,
                 from /usr/include/c++/4.4/bits/char_traits.h:41,
                 from /usr/include/c++/4.4/ios:41,
                 from /usr/include/c++/4.4/istream:40,
                 from /usr/include/c++/4.4/fstream:40,
                 from test.cpp:1:
test.cpp: In constructor ‘std::pair<_T1, _T2>::pair() [with _T1 = const int, _T2 = A]’:
/usr/include/boost/serialization/access.hpp:123:   instantiated from ‘static void boost::serialization::access::construct(T*) [with T = std::pair<const int, A>]’
/usr/include/boost/serialization/serialization.hpp:98:   instantiated from ‘void boost::serialization::load_construct_data(Archive&, T*, unsigned int) [with Archive = boost::archive::xml_iarchive, T = std::pair<const int, A>]’
/usr/include/boost/serialization/serialization.hpp:163:   instantiated from ‘void boost::serialization::load_construct_data_adl(Archive&, T*, unsigned int) [with Archive = boost::archive::xml_iarchive, T = std::pair<const int, A>]’
/usr/include/boost/serialization/detail/stack_constructor.hpp:58:   instantiated from ‘boost::serialization::detail::stack_construct<Archive, T>::stack_construct(Archive&, unsigned int) [with Archive = boost::archive::xml_iarchive, T = std::pair<const int, A>]’
/usr/include/boost/serialization/collections_load_imp.hpp:77:   instantiated from ‘void boost::serialization::stl::archive_input_map<Archive, Container>::operator()(Archive&, Container&, unsigned int) [with Archive = boost::archive::xml_iarchive, Container = std::map<int, A, std::less<int>, std::allocator<std::pair<const int, A> > >]’
/usr/include/boost/serialization/collections_load_imp.hpp:191:   instantiated from ‘void boost::serialization::stl::load_collection(Archive&, Container&) [with Archive = boost::archive::xml_iarchive, Container = std::map<int, A, std::less<int>, std::allocator<std::pair<const int, A> > >, InputFunction = boost::serialization::stl::archive_input_map<boost::archive::xml_iarchive, std::map<int, A, std::less<int>, std::allocator<std::pair<const int, A> > > >, R = boost::serialization::stl::no_reserve_imp<std::map<int, A, std::less<int>, std::allocator<std::pair<const int, A> > > >]’
/usr/include/boost/serialization/map.hpp:50:   instantiated from ‘void boost::serialization::load(Archive&, std::map<Key, Type, Compare, Allocator>&, unsigned int) [with Archive = boost::archive::xml_iarchive, Type = A, Key = int, Compare = std::less<int>, Allocator = std::allocator<std::pair<const int, A> >]’
/usr/include/boost/serialization/split_free.hpp:58:   instantiated from ‘static void boost::serialization::free_loader<Archive, T>::invoke(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_iarchive, T = std::map<int, A, std::less<int>, std::allocator<std::pair<const int, A> > >]’
/usr/include/boost/serialization/split_free.hpp:74:   instantiated from ‘void boost::serialization::split_free(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_iarchive, T = std::map<int, A, std::less<int>, std::allocator<std::pair<const int, A> > >]’
/usr/include/boost/serialization/map.hpp:70:   instantiated from ‘void boost::serialization::serialize(Archive&, std::map<Key, Type, Compare, Allocator>&, unsigned int) [with Archive = boost::archive::xml_iarchive, Type = A, Key = int, Compare = std::less<int>, Allocator = std::allocator<std::pair<const int, A> >]’
/usr/include/boost/serialization/serialization.hpp:133:   instantiated from ‘void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_iarchive, T = std::map<int, A, std::less<int>, std::allocator<std::pair<const int, A> > >]’
/usr/include/boost/archive/detail/iserializer.hpp:170:   instantiated from ‘void boost::archive::detail::iserializer<Archive, T>::load_object_data(boost::archive::detail::basic_iarchive&, void*, unsigned int) const [with Archive = boost::archive::xml_iarchive, T = std::map<int, A, std::less<int>, std::allocator<std::pair<const int, A> > >]’
test.cpp:68:   instantiated from here
test.cpp:17: error: ‘A::A()’ is private
/usr/include/c++/4.4/bits/stl_pair.h:80: error: within this context