How to set permissions to a file using QFile::setPermissions()

[g16bit]

thank you for your supply, but your suggest doesnt work to. I have changed my code like this:

QString savefile = QFileDialog::getSaveFileName(this,"Save File", QDir::currentPath(),fillter0) + ".desktop";
    QFile myfile(savefile);
 
    if(!myfile.setPermissions(QFile::ReadOwner|QFile::WriteOwner|QFile::ExeOwner|QFile::ReadGroup|QFile::ExeGroup|QFile::ReadOther|QFile::ExeOther))
    {
        qDebug("Something wrong!");
    }
 
 
    if(!myfile.open(QIODevice::WriteOnly | QIODevice::Text))
        return;
    QTextStream out(&myfile);
    out << preview;
    myfile.close();

QString savefile = QFileDialog::getSaveFileName(this,"Save File", QDir::currentPath(),fillter0) + ".desktop";
    QFile myfile(savefile);

    if(!myfile.setPermissions(QFile::ReadOwner|QFile::WriteOwner|QFile::ExeOwner|QFile::ReadGroup|QFile::ExeGroup|QFile::ReadOther|QFile::ExeOther))
    {
        qDebug("Something wrong!");
    }


    if(!myfile.open(QIODevice::WriteOnly | QIODevice::Text))
        return;
    QTextStream out(&myfile);
    out << preview;
    myfile.close();

To copy to clipboard, switch view to plain text mode 

But it doesnt work. So i guess it is not beacause the ORed statement. Could you please show me how?
I read the Qt help, but couldnt find any thing could help.
Thank you very much.