Question

If the client is been shutdowned, is the QTcpSocket will recvieve the stateChanged signal immediately?

Answer 1

you can use client signal (disconnected()) at server side to receive the state change signal.

for example:

At Server side

connect(client, SIGNAL(disconnected()), this, SLOT(funcA())); 
//to recieve a signal immediately when client is shutdown

connect(client, SIGNAL(connected()), this, SLOT(funcB()));
// to recieve a signal immediately when client is connected

Hope this will help you.