Hi All, I am getting compiler errors using mingw 3.4.5 on the code below: error: `BaseClass::BaseClass(const std::string&)' is protected I tried to declare as friend the load_construct_data() override in BaseClass but gave me the following error: error: call of overloaded load_constuct_data(..) is ambiguous. What am I doing wrong? TIA, Gvv ... #include <boost/serialization/base_object.hpp> #include <boost/serialization/export.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/serialization/list.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> template <class T> void Serialize(const T& t, std::string& OutData) { std::ostringstream ArchiveStream; boost::archive::text_oarchive Archive(ArchiveStream); Archive << t; OutData = ArchiveStream.str(); } template <class T> void Deserialize(T& t, const std::string& InData) { std::istringstream ArchiveStream(InData); boost::archive::text_iarchive Archive(ArchiveStream); Archive >> t; } class BaseClass : private boost::noncopyable { public: virtual ~BaseClass() {} const std::string& GetName() const { return Name; } protected: BaseClass(const std::string& name) : Name(name) {} private: std::string Name; template<class Archive> void serialize(Archive& ar, const unsigned int version) { ar & Name; } friend class boost::serialization::access; }; typedef boost::shared_ptr<BaseClass> BaseClassPtr; class DerivedClass : public BaseClass { public: DerivedClass(const std::string& name) : BaseClass(name) {} private: template<class Archive> void serialize(Archive& ar, const unsigned int version) { ar & boost::serialization::base_object<BaseClass>(*this); } friend class boost::serialization::access; }; BOOST_CLASS_EXPORT(DerivedClass) namespace boost { namespace serialization { template<class Archive> inline void save_construct_data(Archive& ar, const BaseClass* t, const unsigned int version) { ar << t->GetName(); } template<class Archive> inline void load_construct_data(Archive& ar, BaseClass* t, const unsigned int version) { std::string name; ar >> name; ::new(t)BaseClass(name); } template<class Archive> inline void save_construct_data(Archive& ar, const DerivedClass* t, const unsigned int version) { ar << t->GetName(); } template<class Archive> inline void load_construct_data(Archive& ar, DerivedClass* t, const unsigned int version) { std::string name; ar >> name; ::new(t)DerivedClass(name); } } } int main() { BaseClassPtr b(new DerivedClass("My name is gvv")); std::string data; std::cout << "Serialize" << std::endl; Serialize(b,data); std::cout << data << std::endl; b.reset(); std::cout << "Deserialize" << std::endl; Deserialize(b,data); std::cout << b->GetName() << std::endl; return 0; }