QProgressDialog, bug in Qt 4.8.0 or something else ?

Anticross

I'm using Qt 4.8.0 under Windows OS and I have the division by zero error when set value to 1:
@void QProgressDialog::setValue(int progress)
{
Q_D(QProgressDialog);
if (progress == d->bar->value()
|| (d->bar->value() == -1 && progress == d->bar->maximum()))
return;

d->bar->setValue(progress);

if (d->shown_once) {
    if (isModal())
        QApplication::processEvents();
} else {
    if (progress == 0) {
        d->starttime.start();
        d->forceTimer->start(d->showTime);
        return;
    } else {
        bool need_show;
        int elapsed = d->starttime.elapsed();
        if (elapsed >= d->showTime) {
            need_show = true;
        } else {
            if (elapsed > minWaitTime) {
                int estimate;
                int totalSteps = maximum() - minimum();
                int myprogress = progress - minimum();
                if ((totalSteps - myprogress) >= INT_MAX / elapsed)
                    estimate = (totalSteps - myprogress) / myprogress * elapsed;
                else
                    estimate = elapsed * (totalSteps - myprogress) / myprogress;
                need_show = estimate >= d->showTime;
            } else {
                need_show = false;
            }
        }
        if (need_show) {
            int w = qMax(isVisible() ? width() : 0, sizeHint().width());
            int h = qMax(isVisible() ? height() : 0, sizeHint().height());
            resize(w, h);
            show();
            d->shown_once = true;
        }
    }@

right here @estimate = elapsed * (totalSteps - myprogress) / myprogress;@ I have @myprogress = 0;@ As I see @int myprogress = progress - minimum();@ Where minimum() returns 1 and progress is 1. So when I'm switch to Qt 4.7.4 there is no error using QProgressDialog. So maybe it's a bug in 4.8.0 version.

lgeyer

Related to "http://developer.qt.nokia.com/forums/viewthread/8993":http://developer.qt.nokia.com/forums/viewthread/8993.

Feel free to file a "bugreport":http://developer.qt.nokia.com/doc/qt-4.8/bughowto.html. This behaviour should be fixed.

goetz

The source code of qprogressdialog.cpp did not change between Qt 4.7.4 and 4.8.0.

Anticross

I only show the place where I have error using qt 4.8.0. There is no error using 4.7.4 so I can't know exactly what the reason.

Anticross

Here is my code where I use QProgressDialog:
@ QProgressDialog progress(tr("Save configuration to station"), tr("Abort"), 0, 0, parent);
progress.setWindowModality(Qt::WindowModal);

int offset = 0;
int fullSize = model.getBukDataSize();

if (transfer.startCommit() == false) {
    isAborted = true;
    hasErrors = true;
} else {
    progress.setRange(1, fullSize+1);
    progress.setValue(1);

    int nWrong = 0;

    while (offset < fullSize) {
        qApp->processEvents();

        if (progress.wasCanceled()) {
            isAborted = true;
            break;
        }

        int size = fullSize - offset;
        if (size > packsize)
            size = packsize;

        if (size != transfer.storeCommit(model.getBukData(), offset, size)) {
            if (nWrong > 10) {
                isAborted = true;
                hasErrors = true;
                break;
            }
            nWrong++;
            continue;
        }

        offset += size;
        progress.setValue(offset);
    }
}@

Anticross

So it seemed like I've got a crash when setting value to "1" : @progress.setValue(1);@ I tried to set value to zero before it, as here:http://developer.qt.nokia.com/forums/viewthread/8993 But it has no effect. One more thing: when I make some delay before calling setValue by putting sleep for 10 msecs, all working good.