Hello,
I have difficulties when serializing two objects pointing to each other. The generated archive is fine (I can see both references in it), but when deserializing, only one is restored. In the attached example, I have a collection of nodes, each one is pointing to the previous and to the next node. When deserializing, only the ->next references are restored, all the ->previous are NULL.
I've stepped through your sample program in the debugger and found that this is a bug in the boost::serialization library. The problem lies in the following code from basic_archive_impl::load_pointer // if required if(track_object){ // read data state_saver<bool> x(is_object); is_object = false; // predict next object id to be created object_id_type oid(object_id_vector.size()); if(bis_ptr->tracking()) object_id_vector.push_back(aobject(t, cid)); // because the following operation could move the items // don't use co after this bisp_ptr->load_object_ptr(ar, t, co.file_version); assert(NULL != t); if(bis_ptr->tracking()){ object_id_vector[oid].address = t; // and add to list of created pointers created_pointers.push_back(created_pointer_type(cid, t)); } } This block of code is executed when an object of a certain type is deserialized through a pointer for the first time. This line object_id_vector.push_back(aobject(t, cid)); registers the object ID as stored in the archive of the to-be- deserialized object. If the same object ID is encountered later on in the deserialization process a lookup is performed in object_id_vector in order to retrieve a pointer to the previously deserialized object. Note that t in the above line of code is a reference to the pointer that will point to the object once it is deserialized. However, at the time the above line is executed t is still a NULL pointer. The object will be created in the call to load_object_ptr. In that call the object will be created and deserialized from the archive. In your sample application this will cause other objects to be deserialized that have pointer member variables pointing to the same object t points to, i.e. that have the same object ID. A lookup in object_id_vector is performed to find the corresponding pointer to the object and that pointer is used. But unfortunately, that pointer is still NULL because only after the call to load_object_ptr will the correct address be stored in the object_id_vector in this line of code: object_id_vector[oid].address = t; However, this should happen immediately after space is allocated for the object, i.e. immediately when the object's address is known and _before_ the object is deserialized. I haven't looked any more into it, but I hope it will be easy for Robert to fix. Regards, Martin TAB Austria Industrie- und Unterhaltungselektronik GmbH & CoKG http://www.tab.at