Gennadiy Rozental wrote:
You could use simple map<void*,void*> that mapr raw pointer to an address of shred_ptr
We're using a similar approach in our current version of boost::serialization. Our solution currently stores a raw_ptr-to-shared_ptr<void> map in the input archive object. With this shared_ptr registry in the input archive our non-intrusive serialization code for shared_ptr looks like this (the code for weak_ptr is more or less the same): template<class Archive, class T> inline void save( Archive & ar, const boost::shared_ptr<T> &t, const unsigned int /* file_version */ ){ ar << boost::serialization::make_nvp("px", t.get()); } template<class Archive, class T> inline void load( Archive & ar, boost::shared_ptr<T> &t, const unsigned int /* file_version */ ){ T* r; ar >> boost::serialization::make_nvp("px", r); t = ar.get_shared_ptr_registry().lookup(r); if (!t) { t.reset(r); ar.get_shared_ptr_registry().register_shared_ptr(t); } } template<class Archive, class T> inline void serialize( Archive & ar, boost::shared_ptr<T> &t, const unsigned int file_version ){ boost::serialization::split_free(ar, t, file_version); } So, upon deserialization, when an object pointed to by a shared_ptr is loaded for the first time the shared_ptr instance is registered in the shared_ptr registry of the archive (where it is stored as shared_ptr<void> to allow shared_ptrs that only point to the base class to be retrieved correctly from the registry). In all other cases, the previously deserialized shared_ptr instance is used to create the shared_ptr instance that is currently being deserialized. Note that the lookup function uses a (hackky) reinterpret_cast to convert from the shared_ptr<void> which is stored in the registry to the actually requested shared_ptr<T> type. In practice, this seems to work and the reference count is maintained correctly, but there might be a better solution. Also note that the situation posted by Peter Dimov with multiple inheritance does not work with this solution. Single inheritance should work fine, though. Regards, Martin Ecker TAB Austria Industrie- und Unterhaltungselektronik GmbH & CoKG http://www.tab.at