[Solved] Loading a file larger than 5.242.880 bytes insert newline in QPlainTextEdit

  • Below is a scheme I use to load a large file. But when the file exceeds 5,242,880 bytes, an extra new line is inserted. So character 5.242.881 is inserted on the next line.

    I've created a text file with 32767 lines of exactly 160 bytes (including 2 bytes for \r\n, thus 158 characters + \r\n).
    Line 32768 has exactly 80 characters. This file load fine.

    When I add 1 character to line 32768, this character will be displayed on a new line. Obviously not correct.

    Is this a bug in my code or somewhere else?

    @void MainWindow::openFile(QString filePath)
    if (file->open(QFile::ReadOnly))
    QTimer::singleShot(10, this, SLOT(readFilePart()));


    void MainWindow::readFilePart()
    qint64 bytesRead = file->read(buffer, bufsize - 1);
    buffer[bytesRead] = 0;

    qDebug() << "duration:" << startRead.elapsed() << ", bytesRead:" << bytesRead;

    if (bytesRead == bufsize - 1)
    QTimer::singleShot(10, this, SLOT(readFilePart()));
    qDebug() << "rest: {" << buffer << "}";
    QTimer::singleShot(10, this, SLOT(closeFile()));

    void MainWindow::closeFile()

    project files are at:

  • Moderators

    So if you think there is a bug: "File a bug report":https://bugreports.qt-project.org/ . Talking about it here will unfortunately not get it fixed:/

  • Before filing a bug report I want to exclude making a bug myself :)

    [edit]Which I obviously failed to do ;-)[/edit]

  • Moderators

    Well, the best person to find out whether it is a bug or not is the developer that wrote the code. If you file a bug report that person will notice the issue. If you post it to the forum the likelihood of that happening is way lower. And if you send attach a small project that demonstrates, then the time it takes to reproduce the issue should not be too big. It is pretty easy to reject a bug as invalid. It is much harder finding bugs that people talk about somewhere on the internet:)

    Before somebody suggests maintainers or whoever can just copy the issues from here into the bug tracker: That fails as soon as there is a question back to the user that had the problem. So that is not a solution.

  • This line

    inserts a newline after reading 65535 bytes in my example.

    Issue solved. See bugreport.

Log in to reply

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.