Hi: Ok, having got to grips with fusion, and thought it was working. I now have an issue whereby when using make_shared, it is working in one case, and not in the other. I've got the following definition:P typedef boost::fusion::vector<PmStream*, MIDIInputThread, boost::shared_ptr<boost::asio::io_service> , boost::shared_ptr<boost::thread> > InputType; and when I use: InputType NewInput =InputType(Port, cl, boost::make_shared<boost::asio::io_service> , boost::make_shared<boost::thread>(boost::bind(&boost::asio::io_service::run, io.get()))); Replacing the asio::io declaration with an actual variable of type boost::shared_ptr<boost::asio::io_service> seems to work fine. Is ther anything I'm doing wrong that's not allowing me to use boost::make_shared? Any help appreciated. Regards Sean.