Hi, I just started learning to use serialization and having problems with compiling for hash_map (map/deque/etc all work fine for me). I found your discussion a while ago relating to this http://thread.gmane.org/gmane.comp.lib.boost.user/12609/focus=12609 So I built my test program with g++ -D__GLIBCPP__ -DBOOST_HAS_HASH -DBOOST_STD_EXTENSION_NAMESPACE=__gnu_cxx -c test.cpp -o test.o And I still have the following compile errors saying that serialize function for hash_map is not defined. I also looked at the preprocessor output and did find the definition for hash_map serialize() function. It doesn't make sense to me why this happens. Any help is greatly appreciated. The test file is attached at the end. /usr/local/include/boost/serialization/access.hpp: In static member function 'static void boost::serialization::access::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = __gnu_cxx::hash_map<int, boost::shared_ptr<DaoData>, __gnu_cxx::hash<int>, std::less<int>, std::allocator<boost::shared_ptr<DaoData> > >]': /usr/local/include/boost/serialization/serialization.hpp:81: instantiated from 'void boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = __gnu_cxx::hash_map<int, boost::shared_ptr<DaoData>, __gnu_cxx::hash<int>, std::less<int>, std::allocator<boost::shared_ptr<DaoData> > >]' /usr/local/include/boost/serialization/serialization.hpp:140: instantiated from 'void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = __gnu_cxx::hash_map<int, boost::shared_ptr<DaoData>, __gnu_cxx::hash<int>, std::less<int>, std::allocator<boost::shared_ptr<DaoData> > >]' /usr/local/include/boost/archive/detail/oserializer.hpp:148: instantiated from 'void boost::archive::detail::oserializer<Archive, T>::save_object_data(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::text_oarchive, T = __gnu_cxx::hash_map<int, boost::shared_ptr<DaoData>, __gnu_cxx::hash<int>, std::less<int>, std::allocator<boost::shared_ptr<DaoData> > >]' test.cpp:157: instantiated from here /usr/local/include/boost/serialization/access.hpp:109: error: 'class __gnu_cxx::hash_map<int, boost::shared_ptr<DaoData>, __gnu_cxx::hash<int>, std::less<int>, std::allocator<boost::shared_ptr<DaoData> > >' has no member named 'serialize' ----------------------------------- test.cpp #include <fstream> #include <map> #include <iostream> #include <ext/hash_map> #include <boost/serialization/shared_ptr.hpp> #include <boost/serialization/map.hpp> #include <boost/serialization/hash_map.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/serialization.hpp> using namespace std; using namespace __gnu_cxx; using namespace boost; using namespace boost::serialization; template<typename DataType, typename KeyType, typename CompareType> class DAO { friend class serialization::access; public: typedef shared_ptr<DataType> DataTypePtr; typedef pair<KeyType, DataTypePtr> KeyDataPair; #if 0 typedef map<KeyType, DataTypePtr> DataTypeMap; #else typedef hash_map<KeyType, DataTypePtr, hash<KeyType>, CompareType> DataTypeMap; #endif typedef typename DataTypeMap::iterator DataTypeMapIter; typedef typename DataTypeMap::const_iterator DataTypeMapConstIter; DAO() {} ~DAO() {} template <class Archive> void serialize( Archive& ar, const unsigned int version ) { ar & m_dataTypeMap; } void insertData( DataTypePtr dataPtr ) { m_dataTypeMap.insert( KeyDataPair( dataPtr->getKey(), dataPtr ) ); } void display() const { DataTypeMapConstIter iter = m_dataTypeMap.begin(); while ( iter != m_dataTypeMap.end() ) { iter->second->display(); iter++; } } void save_binary( const char* filename ) { ofstream ofs(filename); archive::text_oarchive oa(ofs); oa & *this; } bool load_binary( const char* filename ) { try { ifstream ifs( "test.dat", ios::binary ); archive::text_iarchive ia( ifs ); ia & *this; display(); return true; } catch ( exception& e ) { cerr << "Exception caught: " << e.what() << endl; return false; } } private: DataTypeMap m_dataTypeMap; }; class DaoData { public: int m_key; string m_keyStr; DaoData() {} DaoData( int key, const string& keyStr ) : m_key( key ), m_keyStr( keyStr ) { } DaoData( DaoData& daoData ) { m_key = daoData.m_key; m_keyStr = daoData.m_keyStr; } ~DaoData() {} int getKey() const { return m_key; } void display() const { cout << "key = " << m_key << endl; cout << "keyStr = " << m_keyStr << endl; } template <class Archive> void serialize( Archive& ar, const unsigned int version ) { ar & m_key; ar & m_keyStr; } }; void test_dao_serialize() { DAO<DaoData, int, less<int> > myDao; shared_ptr<DaoData> dataPtr( new DaoData( 1, "ONE" ) ); myDao.insertData( dataPtr ); shared_ptr<DaoData> dataPtr2( new DaoData( 2, "TWO" ) ); myDao.insertData( dataPtr2 ); myDao.save_binary( "test.dat" ); //myDao.load_binary( "test.dat" ); } int main() { test_dao_serialize(); return 0; }