Obtains the current device position in doubles and modifier state. The position is given in coordinates relative to the upper left corner of window.
pointer gdk.Device to query to.
return location for the X coordinate of device, or NULL.
return location for the Y coordinate of device, or NULL.
return location for the modifier mask, or NULL.
The window underneath device (as with Device.getWindowAtPosition), or NULL if the window is not known to GDK.