I'm trying to send and receive UDP packets through the same endpoint. As far as I know this should be possible. But I can not get it to work with the asio library (version 1.20.0).

This is what I do:

asio::io_context io_context;
asio::ip::udp::socket* udpSendRecvSocket = new asio::ip::udp::socket(io_context, asio::ip::udp::endpoint(asio::ip::udp::v4(), 7782));
asio::error_code ec;

char data[1000];

//
// send packet
//
std::string ipAddress = "127.0.0.1";
asio::ip::address ip_address = asio::ip::address::from_string(ipAddress);
asio::ip::udp::endpoint remoteTarget_endpoint(ip_address, 5500);
udpSendRecvSocket->send_to(asio::buffer(data, 50), remoteTarget_endpoint, 0, ec);
if (ec) {
    return 0;
}

//
// receive packets
//
size_t avLen = udpSendRecvSocket->available(ec);
while (avLen) {
    asio::ip::udp::endpoint remote_endpoint;
    size_t length = udpSendRecvSocket->receive_from(asio::buffer(data, 1000), remote_endpoint, 0, ec);
    int p = remote_endpoint.port();
    if (ec) {
        return 0;
    }
    avLen -= length;
}

The receive does not work correctly. I do receive a packet that I send (from some other app). I know because avLen gets the right value. But when executing the receive_from(), if fails. And the port number in p gets the value 5500. This is the value of the target port of the send_to() call that was executed before. The strange thing is that when I remove the send_to() call, the receive does work correctly and the p will reflect the correct port number of the sending application.

Is this a bug?