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Daytime.5 - A synchronous UDP daytime server

This tutorial program shows how to use asio to implement a server application with UDP.

int main()
    boost::asio::io_service io_service;

Create an ip::udp::socket object to receive requests on UDP port 13.

    udp::socket socket(io_service, udp::endpoint(udp::v4(), 13));

Wait for a client to initiate contact with us. The remote_endpoint object will be populated by ip::udp::socket::receive_from().

    for (;;)
      boost::array<char, 1> recv_buf;
      udp::endpoint remote_endpoint;
      boost::system::error_code error;
          remote_endpoint, 0, error);

      if (error && error != boost::asio::error::message_size)
        throw boost::system::system_error(error);

Determine what we are going to send back to the client.

      std::string message = make_daytime_string();

Send the response to the remote_endpoint.

      boost::system::error_code ignored_error;
          remote_endpoint, 0, ignored_error);

Finally, handle any exceptions.

  catch (std::exception& e)
    std::cerr << e.what() << std::endl;

  return 0;

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