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Serialize std :: unordered_map <int, std :: unordered_set <int>> with a raise

I am trying to serialize / deserialize std::unordered_map < int, std::unordered_set<int> > when I look at boost / serialization / map.hpp, it seems simple (even hard, I don't understand it) The following code seems to compile for serialization, but not suitable for deserialization.

Does anyone know how to do this properly, or can point to some documentation on these STL serialization methods? I did not find something unfortunately ...

 #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <map> #include <unordered_map> #include <unordered_set> #include <boost/serialization/map.hpp> #include <boost/serialization/collections_save_imp.hpp> #include <boost/serialization/collections_load_imp.hpp> #include <boost/serialization/utility.hpp> #include <boost/serialization/split_free.hpp> namespace boost { namespace serialization { template<class Archive, typename... TArgs > inline void save(Archive & ar, std::unordered_map<TArgs...> const&t, unsigned) { boost::serialization::stl::save_collection<Archive, std::unordered_map<TArgs...> >(ar, t); } template<class Archive, typename... TArgs > inline void load(Archive & ar, std::unordered_map<TArgs...> &t, unsigned) { boost::serialization::stl::load_collection<Archive, std::unordered_map<TArgs...>, boost::serialization::stl::archive_input_map< Archive, std::unordered_map<TArgs...> >, boost::serialization::stl::no_reserve_imp<std::unordered_map<TArgs...> > >(ar, t); } // split non-intrusive serialization function member into separate // non intrusive save/load member functions template <class Archive, typename... TArgs> inline void serialize(Archive & ar, std::unordered_map<TArgs...> &t, unsigned file_version) { boost::serialization::split_free(ar, t, file_version); } } } namespace boost { namespace serialization { template<class Archive, typename... TArgs > inline void save(Archive & ar, std::unordered_set<TArgs...> const&t, unsigned) { boost::serialization::stl::save_collection<Archive, std::unordered_set<TArgs...> >(ar, t); } template<class Archive, typename... TArgs > inline void load(Archive & ar, std::unordered_set<TArgs...> &t, unsigned) { boost::serialization::stl::load_collection<Archive, std::unordered_set<TArgs...>, boost::serialization::stl::archive_input_map< Archive, std::unordered_set<TArgs...> >, boost::serialization::stl::no_reserve_imp<std::unordered_set<TArgs...> > >(ar, t); } // split non-intrusive serialization function member into separate // non intrusive save/load member functions template <class Archive, typename... TArgs> inline void serialize(Archive & ar, std::unordered_set<TArgs...> &t, unsigned file_version) { boost::serialization::split_free(ar, t, file_version); } } } int main() { std::stringstream ss; boost::archive::binary_oarchive oa2(ss, boost::archive::no_codecvt | boost::archive::no_header); std::unordered_map<int, std::unordered_set<int> > s, out; s.emplace( 0, std::unordered_set<int>{9,19} ); oa2 << s; // Try to load this!! //boost::archive::binary_iarchive ia2(ss, boost::archive::no_codecvt | boost::archive::no_header); //ia2 >> out; }

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Boost already contains methods for serializing std::unordered_map and std::unordered_set since version 1.5.6 (in fact, they were added in February 2014 )

Therefore, there is no need to write them yourself:

 #include <map> #include <sstream> #include <boost/serialization/serialization.hpp> #include <boost/serialization/unordered_map.hpp> #include <boost/serialization/unordered_set.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> int main() { std::stringstream ss; std::unordered_map<int, std::unordered_set<int> > s, out; s.emplace( 0, std::unordered_set<int>{9,19} ); boost::archive::text_oarchive oarch(ss); oarch << s; boost::archive::text_iarchive iarch(ss); iarch >> out; std::cout << (s == out) << std::endl; }

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