I have a similar piece of code but the one difference I can see is that when I bind the receive socket I also have QUdpSocket::ReuseAddressHint and I use the same parameters on the send socket. I'm not sure if this will help:
udpSocSend = new QUdpSocket(this); udpSocRec = new QUdpSocket(this); udpSocSend->bind(QHostAddress("192.168.0.18"), 6454, QUdpSocket::ShareAddress | QUdpSocket::ReuseAddressHint); udpSocRec->bind(6454, QUdpSocket::ShareAddress | QUdpSocket::ReuseAddressHint); connect(udpSocRec, SIGNAL(readyRead()),this, SLOT(processPendingDatagrams())); The other thing you can do is receive any errors from the socket: connect(udpSocRec, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(SocketError(QAbstractSocket::SocketError))); void SocketError(QAbstractSocket::SocketError) { DbgPrintf(dynamic_cast<QUdpSocket *>(sender())->objectName() + QString(": ") + dynamic_cast<QUdpSocket *>(sender())->errorString()); } Tom Isaacson -----Original Message----- From: interest-bounces+tom.isaacson=navico....@qt-project.org [mailto:interest-bounces+tom.isaacson=navico....@qt-project.org] On Behalf Of Robert Wood Sent: Tuesday, 24 June 2014 12:03 a.m. To: interest@qt-project.org Subject: [Interest] Simple UDP listener question Folks, I've managed to get a simple program going that sends out a UDP packet to a broadcast address (an Artnet Poll packet) and my embedded software is receiving this and sending out a Poll reply. Wireshark confirms that my embedded device is sending out the correct response, however, my Qt program is not picking up any reply at all. I should say, this is the first time I've used Qt for networking and it's my first embedded netowrking project, so I may be missing some very basic point. I am doing this in MainWindow initialisation: udpSocSend = new QUdpSocket(this); udpSocRec = new QUdpSocket(this); udpSocSend->bind(QHostAddress("192.168.0.18"),6454); udpSocRec->bind(6454, QUdpSocket::ShareAddress); connect(udpSocRec, SIGNAL(readyRead()),this, SLOT(processPendingDatagrams())); void MainWindow::processPendingDatagrams() { while (udpSocRec->hasPendingDatagrams()) { QByteArray datagram; datagram.resize(udpSocRec->pendingDatagramSize()); udpSocRec->readDatagram(datagram.data(), datagram.size()); ui->textEdit->setText(tr("Received datagram: \"%1\"").arg(datagram.data())); } } My udpSocSend is working to send data out (an Artnet Poll), my STM32 (embedded micro) is sending packets back according to Wireshark, but processPendingDatagrams() flatly refuses to be called! Wireshark shows this in terms of a reply: 2475 795.416268000 192.168.0.177 192.168.0.18 ARTNET 282 ArtPollReply (0x2100) The STM32 is at address 192.168.0.177, my [Linux] Qt machine is 192.168.0.18. The data in the datagram looks OK mto me on Wireshark. Can anyone see anything I am doing wrong please? Thanks! Rob _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest