How get a pointer to the parent widget

[franco.amato]

Hi to all,
in my application I have this widget structure:

QmainWindow -> CentralWidget -> QWidget

The QMainWindow contains a central widget, and this one contains 2 QWidget.
I would call directly a method of QMainWindow from one of the QWidget is possible?
I saw the QWidget::parentWidget() but I don't think it returns a pointer of the QMainWindow.
I would know if it's possible or if I need to pass a pointer into the ctor.

Best Regards,
Franco