echo_udp_server.cpp

#include <boost/asio.hpp>
#include <iostream>

int main(int, char **)
{
    boost::asio::io_context context;

    const boost::asio::ip::udp::endpoint ep{boost::asio::ip::udp::v4(), 8080};
    boost::asio::ip::udp::socket s{context, ep};

    while (true)
    {
        boost::system::error_code ec;

        std::array<std::uint8_t, 1024> discard_buffer;

        while (!ec)
        {
            boost::asio::ip::udp::endpoint peer;

            auto l = s.receive_from(
                boost::asio::buffer(discard_buffer), peer, 0, ec);
            if (ec) break;

            s.send_to(boost::asio::const_buffer{discard_buffer.data(), l}, peer,
                0, ec);
        }
    }

    s.close();
}