QT: How can the server know which socket has disconnected?

Question

Qt

Hello, I am writing a small client-server application in Qt. I am using QTcpServer. All connections are stored in (handle and socket pointer). When the socket is disconnected, slotDisconnected() is called, which should remove the connection information from the QMap:QMap<int,QTcpSocket*>

int userId= ((QTcpSocket*)sender())->socketDescriptor();
Clients.remove(userId);

This is where the error lies. The userId descriptor is always -1 because the socket object itself has already been destroyed.
In this case, how do you know which QMap element to remove? Identify everything via IP and port number?

Answer 1

Delete the one that the return value points to sender(), you didn't copy the object when you added the pointer to the container, which means it's the same object, I don't know about QMap, but usually lists support deleting an object without a key or index, in a special method you pass a pointer and the list removes that element.
If this is a problem, then yes, implement your own identification.