How to set selected filter on QFileDialog?

Like this:

QString selfilter = tr("JPEG (*.jpg *.jpeg)");
QString fileName = QFileDialog::getOpenFileName(
        this,
        title,
        directory,
        tr("All files (*.*);;JPEG (*.jpg *.jpeg);;TIFF (*.tif)" ),
        &selfilter 
);

The docs are a bit vague about this, so I found this out via guessing.