text: //
  // server.cpp
  // ~~~~~~~~~~
  //
  // Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  //
  // Distributed under the Boost Software License, Version 1.0. (See accompanying
  // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  
  #include <ctime>
  #include <iostream>
  #include <string>
  #include <boost/array.hpp>
  #include <boost/bind.hpp>
  #include <boost/shared_ptr.hpp>
  #include <boost/enable_shared_from_this.hpp>
  #include <boost/asio.hpp>
  
  using boost::asio::ip::tcp;
  using boost::asio::ip::udp;
  
  std::string make_daytime_string()
  {
    using namespace std; // For time_t, time and ctime;
    time_t now = time(0);
    return ctime(&now);
  }
  
  class tcp_connection
    : public boost::enable_shared_from_this<tcp_connection>
  {
  public:
    typedef boost::shared_ptr<tcp_connection> pointer;
  
    static pointer create(boost::asio::io_service& io_service)
    {
      return pointer(new tcp_connection(io_service));
    }
  
    tcp::socket& socket()
    {
      return socket_;
    }
  
    void start()
    {
      message_ = make_daytime_string();
  
      boost::asio::async_write(socket_, boost::asio::buffer(message_),
          boost::bind(&tcp_connection::handle_write, shared_from_this()));
    }
  
  private:
    tcp_connection(boost::asio::io_service& io_service)
      : socket_(io_service)
    {
    }
  
    void handle_write()
    {
    }
  
    tcp::socket socket_;
    std::string message_;
  };
  
  class tcp_server
  {
  public:
    tcp_server(boost::asio::io_service& io_service)
      : acceptor_(io_service, tcp::endpoint(tcp::v4(), 13))
    {
      start_accept();
    }
  
  private:
    void start_accept()
    {
      tcp_connection::pointer new_connection =
        tcp_connection::create(acceptor_.io_service());
  
      acceptor_.async_accept(new_connection->socket(),
          boost::bind(&tcp_server::handle_accept, this, new_connection,
            boost::asio::placeholders::error));
    }
  
    void handle_accept(tcp_connection::pointer new_connection,
        const boost::system::error_code& error)
    {
      if (!error)
      {
        new_connection->start();
        start_accept();
      }
    }
  
    tcp::acceptor acceptor_;
  };
  
  class udp_server
  {
  public:
    udp_server(boost::asio::io_service& io_service)
      : socket_(io_service, udp::endpoint(udp::v4(), 13))
    {
      start_receive();
    }
  
  private:
    void start_receive()
    {
      socket_.async_receive_from(
          boost::asio::buffer(recv_buffer_), remote_endpoint_,
          boost::bind(&udp_server::handle_receive, this,
            boost::asio::placeholders::error));
    }
  
    void handle_receive(const boost::system::error_code& error)
    {
      if (!error || error == boost::asio::error::message_size)
      {
        boost::shared_ptr<std::string> message(
            new std::string(make_daytime_string()));
  
        socket_.async_send_to(boost::asio::buffer(*message), remote_endpoint_,
            boost::bind(&udp_server::handle_send, this, message));
  
        start_receive();
      }
    }
  
    void handle_send(boost::shared_ptr<std::string> /*message*/)
    {
    }
  
    udp::socket socket_;
    udp::endpoint remote_endpoint_;
    boost::array<char, 1> recv_buffer_;
  };
  
  int main()
  {
    try
    {
      boost::asio::io_service io_service;
      tcp_server server1(io_service);
      udp_server server2(io_service);
      io_service.run();
    }
    catch (std::exception& e)
    {
      std::cerr << e.what() << std::endl;
    }
  
    return 0;
  }
  