Qt: default connection timeout for QTcpSocket

Question

Please advise how can I setup default connection timeout without using blocking waitForConnected() method? I noticed that socket emit error signal (QAbstractSocket::SocketTimeoutError) after about 60 seconds that I can handle as a timeout, but can this timeout be adjusted?

Solution

You could use a QTimer:

• Start it after you have called connectToHost.
• You may want to reset the timer when socket state changes from QAbstractSocket::HostLookupState to QAbstractSocket::ConnectingState, perhaps with different timeout, if you want more fine-grained control on when exactly will the timeout happen.
• If you get connection, stop the timer, or reset it for similar send/receive timeout use.
• If you get timer timeout, do disconnectFromHost() and possibly do something like retry when you get disconnect signal.

When developing, make sure to connect the stateChanged(...) and error(...) signals at least to debug slots, which just print the arguments. That way you will see when something happens in a way you did not expect.