1. What is BOOST_EXTENSIONS_IMPL_NAMESPACE_BEGIN used for? It doesnt seem to add anything useful. Just complicates the implementation. 2. Why is functor defined? Why not use boost::bind and boost::function ? 3. Why does shared_library have two-phase construction? It seems to be common knowledge that two-phase construction is bad. IMO, a default-constructor and a constructor that throws would be better. And member functions for both options too. Now, IMO, factories are unnecessarily complicating the library. Couldn't a different approach be pursued? Like serialization does for type registration. Best regards, -- Felipe Magno de Almeida