Qt - как создать окно во весь экан ?

void QWidget::showFullScreen () [slot]

Shows the widget in full-screen mode. Calling this function only affects top-level widgets. To return from full-screen mode, call showNormal(). Full-screen mode works fine under Windows, but has certain problems under X. These problems are due to limitations of the ICCCM protocol that specifies the communication between X11 clients and the window manager. ICCCM simply does not understand the concept of non-decorated full-screen windows. Therefore, the best we can do is to !!!request a !!!borderless !!!window and !!!place and !!!resize it to fill the entire screen. Depending on the window manager, this may or may not work. The borderless window is requested using MOTIF hints, which are at least partially supported by virtually all modern window managers. An alternative would be to bypass the window manager entirely and create a window with the !!!WX11BypassWM flag. This has other severe problems though, like totally broken keyboard focus and very strange effects on desktop changes or when the user raises other windows. Future X11 window managers that follow modern post-ICCCM specifications may support full-screen mode properly.

спасибо !!!