Hello, The UDP async server example opens the udp socket like so: a) udp::socket::socket(io_service, udp::endpoint(udp::v4(), 13)) Boost's comment regarding this invocation: * This constructor creates a datagram socket and automatically opens it bound * to the specified endpoint on the local machine. The protocol used is the * protocol associated with the given endpoint. Please consider the udp::socket constructor that takes only an io_service: b) explicit basic_datagram_socket(boost::asio::io_service& io_service) Commented as: * This constructor creates a datagram socket without opening it. The open() * function must be called before data can be sent or received on the socket. And finally, udp::socket::open: (c) void open(const protocol_type & protocol = protocol_type()); Please note that (a) takes an endpoint while (c) takes a protocol. === Question: How can I effectively call (a) using the two-part invocation (b) then (c)? Answer: 1) Just call udp::socket::open(endpoint(udp::v4(), 13)); 2) This is impossible because (a) takes a endpoint while (c) wants a protocol 3) Why would you want to do that you moron? 4) Why don't you write your own udp::socket::open that takes an endpoint if you are so smart? Try giving back to the community instead of just taking. You are a leech and not worthy of reading this mailing list let alone posting to it. 5) none of the above Note: (1) fails with error: no matching function for call to 'boost::asio::basic_datagram_socket<boost::asio::ip::udp>::open(boost::asio::ip::udp::endpoint)' Thank you, Chris