qt5base-lts/examples/network/multicastreceiver/receiver.cpp
Robin Burchell c82d40749d Fix multicast join/leave when binding to QHostAddress::Any.
On OS X and Windows, this was not working, because the socket was being bound
in v6 mode (due to ::Any being for dual mode), but the address passed was a v4
address, meaning it took the wrong codepath. Linux, strangely, apparently works
anyway.

This is fixable in OS X (by using the v6 join path when bound in v6/dual mode),
but the same fix doesn't work on Windows, failing with WSAEADDRNOTAVAIL.

Don't allow this behaviour, and provide a sane error message telling the user
what to do instead.

Done-with: Shane Kearns
Task-number: QTBUG-25047
Change-Id: Iaf5bbee82e13ac92e11b60c558f5af9ce26f474b
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>
2012-04-02 12:49:38 +02:00

85 lines
3.3 KiB
C++

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#include <QtWidgets>
#include <QtNetwork>
#include "receiver.h"
Receiver::Receiver(QWidget *parent)
: QDialog(parent)
{
groupAddress = QHostAddress("239.255.43.21");
statusLabel = new QLabel(tr("Listening for multicasted messages"));
quitButton = new QPushButton(tr("&Quit"));
udpSocket = new QUdpSocket(this);
udpSocket->bind(QHostAddress::AnyIPv4, 45454, QUdpSocket::ShareAddress);
udpSocket->joinMulticastGroup(groupAddress);
connect(udpSocket, SIGNAL(readyRead()),
this, SLOT(processPendingDatagrams()));
connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
QHBoxLayout *buttonLayout = new QHBoxLayout;
buttonLayout->addStretch(1);
buttonLayout->addWidget(quitButton);
buttonLayout->addStretch(1);
QVBoxLayout *mainLayout = new QVBoxLayout;
mainLayout->addWidget(statusLabel);
mainLayout->addLayout(buttonLayout);
setLayout(mainLayout);
setWindowTitle(tr("Multicast Receiver"));
}
void Receiver::processPendingDatagrams()
{
while (udpSocket->hasPendingDatagrams()) {
QByteArray datagram;
datagram.resize(udpSocket->pendingDatagramSize());
udpSocket->readDatagram(datagram.data(), datagram.size());
statusLabel->setText(tr("Received datagram: \"%1\"")
.arg(datagram.data()));
}
}