QtConcurrent pause

[MarKac]

Hi,

I'm having problems with QtConcurrent, how to pause execution of QtConcurrent function (thread) ?
I've tried QFuture setPaused(true) and pause() but that does not work. Let say I have code like this:

void MainWindow::on_pushButton_clicked() // run button
{
    future = QtConcurrent::run(this, &MainWindow::my_func);
    watcher.setFuture(future);
}
 
void MainWindow::on_pushButton_2_clicked() //pause button
{
    future.pause();
    return;
}
 
void MainWindow::my_func()
{
    qDebug()<< "time-consuming code start";
    for (int i = 0; i < 8000; i++)
    {
        for (int j = 1; j< 1000; j++)
        {
            sum = sum * i / j;
            QApplication::processEvents();
 
        }
    }
    qDebug()<< "time-consuming code end";
}

void MainWindow::on_pushButton_clicked() // run button
{
    future = QtConcurrent::run(this, &MainWindow::my_func);
    watcher.setFuture(future);
}

void MainWindow::on_pushButton_2_clicked() //pause button
{
    future.pause();
    return;
}

void MainWindow::my_func()
{
    qDebug()<< "time-consuming code start";
    for (int i = 0; i < 8000; i++)
    {
        for (int j = 1; j< 1000; j++)
        {
            sum = sum * i / j;
            QApplication::processEvents();

        }
    }
    qDebug()<< "time-consuming code end";
}

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When I press pause button my_func() still continues, thread is not paused. what am I doing wrong, how to pause execution of my_func ?
Thanks in advance.

[Santosh Reddy]

You cannot stop the thread.

Qt Doc Say's

Note that the QFuture returned by QtConcurrent::run() does not support canceling, pausing, or progress reporting. The QFuture returned can only be used to query for the running/finished status and the return value of the function.

[anda_skoa]

And better not use a member function in a UI class, you could be tempted to do UI stuff in it and that would not be OK with a secondary thread.
Also remove the QApplication:rocessEvent(), the worker thread should not do that either.

Cheers,
_