If I have a socket like so: boost::asio::ip::tcp::socket tcpSocket; and call connect in a boost::thread like so: tcpSocket.connect(endPoint, error); It will 'hang' for up to 30 seconds if it can't immediately connect to the end point. If I interrupt() and join() the boost thread it has to wait for the connect() call to finish. Is there a way to cancel or interrupt the connect() call? Thanks Simon