connectToHost() to receive broadcast udp datagram

[mastupristi]

Can I use QAbstractSocket::connectToHost() to receive broadcast udp datagrams?

If I try the unmodified broadcastsender/receiver all works and netstat is:

Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
udp6       0      0 :::52337                :::*                                12185/./broadcastse 
udp6       0      0 :::45454                :::*                                12172/broadcastrece

Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
udp6       0      0 :::52337                :::*                                12185/./broadcastse 
udp6       0      0 :::45454                :::*                                12172/broadcastrece

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I modified broadcastreceiver as follow:

//! [0]
    udpSocket = new QUdpSocket(this);
    udpSocket->bind(45454, QUdpSocket::ShareAddress);
    udpSocket->connectToHost(QHostAddress(QHostAddress::Any),0); // <- added line
//! [0]

//! [0]
    udpSocket = new QUdpSocket(this);
    udpSocket->bind(45454, QUdpSocket::ShareAddress);
    udpSocket->connectToHost(QHostAddress(QHostAddress::Any),0); // <- added line
//! [0]

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Now it does not receive broadcast datagrams, but it receive correctly unicast datagrams.

the netstat command report is:

Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
udp6       0      0 ::1:45454               ::1:*                   ESTABLISHED 11488/broadcastrece

Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
udp6       0      0 ::1:45454               ::1:*                   ESTABLISHED 11488/broadcastrece

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I wonder why it seems different local address, and where am I wrong.

here is attached the examples
qt5-examples.tar.gz

best regards
Max

[Santosh Reddy]

UDP is normally used is connection-less mode, so connectToHost() is not required, unless you are doing something special.

If you are sure you want to connect, specify a specific remote host name / remote ip address you want to connect. QHostAddress::Any is not an appropriate argument to connectToHost().