how to get/set window size and position

[Mikko Rantalainen <mira st jyu fi>]

I want to save all window positions and sizes of my application when user
exits. How do I get window sizes and positions (when I have pointers of
type GtkWindow only). Also how do I set position of GtkWindow?

With gtk_window_set_position I cannot set window to e.g. +10+25 and I
cannot find any documentation about gtk_window_set_geometry_hints so I
don't know if I should use that.

-- Mikko Rantalainen