You have the option of using m_endpoint.set_timer(300000,(bind(&type::yourFunc,this,::_1)));
yourFunc must be of the form: void yourwebsocketppObjectName::yourFunc(const websocketpp::lib::error_code &ec) having passed in const websocketpp::lib::error_code ec;
Also you may have to save hdl to an (maybe global?) object to access it in yourFunc.