How to get a window position?

[jca <jca mail phm vcu edu>]

  I have a window that hides and then reappears.  I want it to reappear
in the same place the user left it before it was hidden.

  I can put the window wherever I want with gtk_window_set_position...
but how do I query the window's position in the first place before it
hides?  There's no gtk_window_get_position.

  Thanks,
  jca