QThread Proper Use ?? connect Problems....

[anda_skoa]

- redefinition of methods run() of Object inheriting of QThread class => Wrong way

- definition of a Worker and worker->moveToThread (QThread*) => Right way ??? (https://forum.qt.io/topic/14378/my-t...y-use-qthreads)

Both options are OK, it depends on what the thread does.
The first is the better option for something that is a single, long operation, the second is a good option for things that need events while processing.

I developed a small project with these two methods to compare them. threadA which displays "A" and threadB which displays "B". To start/stop each threads, there are buttons. Both of these methods work (displaying AAAAA when AButton pushed, BBBBBBB when BButton pushed and ABABABABABA when both are pushed...

I personally would chose option 1 for that, way easier IMHO.

but when I add these two connections, I have : Violation of Ox0FFFFFFFF emplacement Mutex....

connect(worker, SIGNAL(finished()), worker, SLOT(deleteLater())); 
connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));

connect(worker, SIGNAL(finished()), worker, SLOT(deleteLater())); 
connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));

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At which of the two connects to you get the error?
It looks fine.

Other question, in my code when i'm displaying threadID, it always displays 00000000159 (for example), for both threads ! I think I'm missing something.... Thread must NOT have the same ID ???? principles ??? (same problem in the two methods)

Your worker code does not output any thread ID, you only ever write the main thread's ID in the dialog code.

Worker.cpp

Worker::Worker() { stopped = false;} // attribute of Worker instance
 
void Worker::process()
{
   while (!stopped)
      std::cout << messageStr.toStdString(); // attribute of Worker instance
  emit finished();
}
 
void Worker::stop() { stopped = true;}
void Worker::start() {stopped = false;}

Worker::Worker() { stopped = false;} // attribute of Worker instance

void Worker::process()
{
   while (!stopped)
      std::cout << messageStr.toStdString(); // attribute of Worker instance
  emit finished();
}

void Worker::stop() { stopped = true;}
void Worker::start() {stopped = false;}

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Concurrent access to members by multiple threads needs to be serialized, e.g. by using a mutex.
Here that is the access to "stopped", which is accessed by the worker thread in process() and by the main thread in stop() and start().

void ThreadDialog::closeEvent(QCloseEvent *event)
{
   workerA->stop();
   workerB->stop();
   threadA->wait();
   threadB->wait();
   threadA->exit();
   threadB->exit();
 
   event->accept();
}

void ThreadDialog::closeEvent(QCloseEvent *event)
{
   workerA->stop();
   workerB->stop();
   threadA->wait();
   threadB->wait();
   threadA->exit();
   threadB->exit();

   event->accept();
}

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QThread::exit() doesn't make much sense here. When wait() returns the thread has already exited.

Cheers,
_