Qt C++ how stop thread if moveToThread

Question

After lots of experimentation and learning from stackoverflow, I've create a QObject worker, a QThread, and moved my QObject worker to my QThread, and started the QThread - and it's working!

void TelnetServer::incomingConnection(qintptr socketDescriptor)
{
    QThread * TelnetConnectionThread = new QThread(this);
    TelnetConnection *worker = new TelnetConnection(socketDescriptor,TelnetConnectionThread);
    connect(TelnetConnectionThread, SIGNAL(started()), worker, SLOT(start()));
    connect(TelnetConnectionThread, SIGNAL(finished()), worker, SLOT(deleteLater()));
    worker->moveToThread(TelnetConnectionThread);
    TelnetConnectionThread->start();  // Start the thread running
}

I assume that calling TelnetConnectionThread->start() starts the eventloop within the QThread (since it seems to be running). Now the problem...how do I stop the thread? I tried:

QThread::quit();

but the thread is still running when I shutdown the app. Does this mean the exec loop is not running? Do I have to do something else to stop this thread? Or is it actually stopped but just not deleted?

BTW, you're using the old code from my answer, you may want to look at the refactoring I've done, you don't need to derive from `QTcpServer` anymore :) — Kuba hasn't forgotten Monica, Oct 10 '13 at 17:37

score -1 · Answer 1 · answered Oct 10 '13 at 15:06

-1

It's a bad idea to kill running thread, from design and technical points of view. Usually the thread must own the decision to quit based on "terminate" flag. For example create new flag "stop", if quit() slot is signaled mark the flag true. In a thread function verify the flag periodically and if it's true - exit thread function.

answered Oct 10 '13 at 15:06

Iuri Covalisin

645
4
7

This code actually sets up an event loop inside the QThread. From the documentation, quit() is supposed to gracefully exit. I have a feeling that the thread methods just have nothing listening to quit... – shash Oct 10 '13 at 15:08
3

I figured it out...I had to connect the thread's finished signal to the thread's deletelater slot; then it worked. So the thread was stopped, just not deleted – TSG Oct 10 '13 at 15:26

Qt C++ how stop thread if moveToThread

1 Answers1