module GraphicsX11: sig .. end
Additional graphics primitives for the X Windows system.
type string 
val window_id : unit -> window_id
Return the unique identifier of the OCaml graphics window.
   The returned string is an unsigned 32 bits integer
   in decimal form.
val open_subwindow : x:int -> y:int -> width:int -> height:int -> window_id
Create a sub-window of the current OCaml graphics window
   and return its identifier.
val close_subwindow : window_id -> unit
Close the sub-window having the given identifier.