1 //
2 // blocking_udp_echo_server.cpp
3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com)
6 //
7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9 //
10
11 #include <cstdlib>
12 #include <iostream>
13 #include "asio.hpp"
14
15 using asio::ip::udp;
16
17 enum { max_length = 1024 };
18
server(asio::io_context & io_context,unsigned short port)19 void server(asio::io_context& io_context, unsigned short port)
20 {
21 udp::socket sock(io_context, udp::endpoint(udp::v4(), port));
22 for (;;)
23 {
24 char data[max_length];
25 udp::endpoint sender_endpoint;
26 size_t length = sock.receive_from(
27 asio::buffer(data, max_length), sender_endpoint);
28 sock.send_to(asio::buffer(data, length), sender_endpoint);
29 }
30 }
31
main(int argc,char * argv[])32 int main(int argc, char* argv[])
33 {
34 try
35 {
36 if (argc != 2)
37 {
38 std::cerr << "Usage: blocking_udp_echo_server <port>\n";
39 return 1;
40 }
41
42 asio::io_context io_context;
43
44 server(io_context, std::atoi(argv[1]));
45 }
46 catch (std::exception& e)
47 {
48 std::cerr << "Exception: " << e.what() << "\n";
49 }
50
51 return 0;
52 }
53