text: //
  // receiver.cpp
  // ~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2014 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 <iostream>
  #include <string>
  #include <boost/asio.hpp>
  #include "boost/bind.hpp"
  
  const short multicast_port = 30001;
  
  class receiver
  {
  public:
    receiver(boost::asio::io_service& io_service,
        const boost::asio::ip::address& listen_address,
        const boost::asio::ip::address& multicast_address)
      : socket_(io_service)
    {
      // Create the socket so that multiple may be bound to the same address.
      boost::asio::ip::udp::endpoint listen_endpoint(
          listen_address, multicast_port);
      socket_.open(listen_endpoint.protocol());
      socket_.set_option(boost::asio::ip::udp::socket::reuse_address(true));
      socket_.bind(listen_endpoint);
  
      // Join the multicast group.
      socket_.set_option(
          boost::asio::ip::multicast::join_group(multicast_address));
  
      socket_.async_receive_from(
          boost::asio::buffer(data_, max_length), sender_endpoint_,
          boost::bind(&receiver::handle_receive_from, this,
            boost::asio::placeholders::error,
            boost::asio::placeholders::bytes_transferred));
    }
  
    void handle_receive_from(const boost::system::error_code& error,
        size_t bytes_recvd)
    {
      if (!error)
      {
        std::cout.write(data_, bytes_recvd);
        std::cout << std::endl;
  
        socket_.async_receive_from(
            boost::asio::buffer(data_, max_length), sender_endpoint_,
            boost::bind(&receiver::handle_receive_from, this,
              boost::asio::placeholders::error,
              boost::asio::placeholders::bytes_transferred));
      }
    }
  
  private:
    boost::asio::ip::udp::socket socket_;
    boost::asio::ip::udp::endpoint sender_endpoint_;
    enum { max_length = 1024 };
    char data_[max_length];
  };
  
  int main(int argc, char* argv[])
  {
    try
    {
      if (argc != 3)
      {
        std::cerr << "Usage: receiver <listen_address> <multicast_address>\n";
        std::cerr << "  For IPv4, try:\n";
        std::cerr << "    receiver 0.0.0.0 239.255.0.1\n";
        std::cerr << "  For IPv6, try:\n";
        std::cerr << "    receiver 0::0 ff31::8000:1234\n";
        return 1;
      }
  
      boost::asio::io_service io_service;
      receiver r(io_service,
          boost::asio::ip::address::from_string(argv[1]),
          boost::asio::ip::address::from_string(argv[2]));
      io_service.run();
    }
    catch (std::exception& e)
    {
      std::cerr << "Exception: " << e.what() << "\n";
    }
  
    return 0;
  }
  