Hello, I was wondering what the best way would be to extend the serialization library to allow storing state in e.g. the archive objects during the serialization process. We could use such a facility in our project for various purposes. For example, it would be possible to influence the serialization of certain classes, i.e. make them write out only their internal state but not any pointers or references to other objects, or something like that. Another use case for having state variables in archives: We're using another library in our project that has its own serialization system. So instead of writing boost::serialization code for the classes of this library we want to use its serialization system. This is straightforward enough by having the library serialize into a memory buffer which is then written out using boost::serialization's binary_object. However, we also need to do proper tracking of pointers for that library, so we can't just create a new memory buffer every time we encounter a pointer to one of its objects during serialization. Therefore it would be convenient to store an "archive" object of the library's serialization system (which calls an archive a "stream") in the boost::serialization archive and simply write all objects of the library we encounter to it. The library's serialization system will track all these objects for us in a similar way boost::serialization does. Then at the end of the serialization process we write the additional serialization data out to the archive using a binary_object. In general, there are a lot of use cases I can think of where having state variables in an archive is useful (setting flags to influence the serialization process, deserializing smart pointers, registering objects upon deserialization in some kind of object registry, etc.). One way of achieving all this would, of course, be to derive from one of the existing archive classes and add the required functionality. However, we don't want to lose the flexibility of being able to write out data to a binary, text, XML, or any other archive with some other kind of representation. So basically we're looking for a good way of inserting an additional layer in between the archives and the actual serialize functions that can store state variables. Thanks for any comments. Best Regards, Martin Ecker TAB Austria Industrie- und Unterhaltungselektronik GmbH & CoKG http://www.tab.at