Detailed Description
The QUdpSocket class provides a UDP socket.
UDP (User Datagram Protocol) is a lightweight, unreliable, datagram-oriented, connectionless protocol. It can be used when reliability isn’t important. QUdpSocket is a subclass of QAbstractSocket that allows you to send and receive UDP datagrams.
The most common way to use this class is to bind to an address and port using bind(), then call writeDatagram() and readDatagram() to transfer data. If you want to use the standard QIODevice functions read(), readLine(), write(), etc., you must first connect the socket directly to a peer by calling connectToHost().
The socket emits the bytesWritten() signal every time a datagram is written to the network. If you just want to send datagrams, you don’t need to call bind().
The readyRead() signal is emitted whenever datagrams arrive. In that case, hasPendingDatagrams() returns true. Call pendingDatagramSize() to obtain the size of the first pending datagram, and readDatagram() to read it.
Note: An incoming datagram should be read when you receive the readyRead() signal, otherwise this signal will not be emitted for the next datagram.
Example:
void Server::initSocket()
{
udpSocket = new QUdpSocket(this);
udpSocket->bind(QHostAddress::LocalHost, 7755);
connect(udpSocket, SIGNAL(readyRead()),
this, SLOT(readPendingDatagrams()));
}
void Server::readPendingDatagrams()
{
while (udpSocket->hasPendingDatagrams()) {
QByteArray datagram;
datagram.resize(udpSocket->pendingDatagramSize());
QHostAddress sender;
quint16 senderPort;
udpSocket->readDatagram(datagram.data(), datagram.size(),
&sender, &senderPort);
processTheDatagram(datagram);
}
}