"Unhandled exception at 0x000007FEFD5D7C8A (ole32.dll) in myprogram.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF"

Question

I'm trying to use QfileDialog (as a static fct) for the user to select and read a ".txt" file, as follow:

void VisOCMConfig::readNmbTiles()
{
    QString  m_findFile;
    m_findFile = QFileDialog::getOpenFileName(0, tr("Open TextFile"),
                                              QDir::homePath(), tr("Text files (*.txt)"));

    QFile myfile(m_findFile);
    if (!myfile.open(QIODevice::ReadOnly | QIODevice::Text))
        return;
    else 
        while (!myfile.atEnd()) 
        {
            m_scanPos = myfile.readLine();
            m_nmbofLines++;
        }

    myfile.close();
    qDebug() << "Scan Positions: (" << m_scanPos.size() << "): " << m_scanPos;
    m_nmbofScan->setText(QString("#Tiles: %1").arg(m_nmbofLines));
}

Where m_scanPos is a QByteArray initialized in VisOCMConfig.h.

When I run the programm, It works correctly until a break occurs suddenly with the following message:

Unhandled exception at 0x000007FEFD5D7C8A (ole32.dll) in VisOCMConfig.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF

I read on other questions that it might be due to the use of null pointer but i'm still lost about it. Can you identify my mistake?

Answer 1

I've been having the same issue. Try using "DontUseNativeDialog" as a flag. I believe this solves the crash, but then you are left with a non-native dialog.

Answer 2

I have the same problem. Solution is also to use a non-native QFileDialog. Actually it only appears in Debug mode. In Release mode evething is fine.

The same code is working under QT4.8. Somehow it is not when using QT5.6.

Answer 3

Those who downvoted this question (I upvoted it) are more than welcome to downvote also this my answer.

I have the same problem with Qt 5.2.1 - same exception in ole32.dll after using QFileDialog::getOpenFileName() - not immediately but after 10 - 60 seconds. It happens if I continue with application AND ALSO if do nothing after opening file, just wait some time. Using "DontUseNativeDialog" as suggested by @aeson and @guest avoids this problem. I hope this information can help others.

@MartinBonner I think the tag should be changed back to QFileDialog because the problem is clearly related to it

Answer 4

I had the same error - my application crashed in debug mode.

If you examine the call stack when this issue occurs, you notice that the issue is related to the NetworkItemFactory.dll component.

A similar problem is described here: Unhandled exception in marshal.cxx under VS2013

Microsoft fixed this, so the solution is to apply Microsoft's hotfix Windows6.1-KB2718841