(* Simple hello-world OCaml GTK program for Lablgtk. 
   You can compile it like this:

        ocamlfind ocamlc -g -package lablgtk2 -linkpkg gtkhello.ml -o gtkhello

   or substitute `ocamlopt` for `ocamlc` for a native executable.

   You may previously need to run

       sudo apt-get install ocaml-findlib liblablgtk2-ocaml-dev

   *)

(* http://osdir.com/ml/lang.ocaml.lib.gtk/2004-08/msg00007.html
explains that, unless you include `lablgtk.cma` in your link line
before this code, and also fail to do `GtkMain.Main.init ()`, it will
first warn:

    (process:10432): Gtk-WARNING **: Screen for GtkWindow not set; you must always set
    a screen for a GtkWindow before using the window

and then segfault.  None of the examples in
/usr/share/doc/liblablgtk2-ocaml-doc/examples/ invoke
`GtkMain.Main.init`, so presumably you have to link them with
`lablgtk.cma`?  But it doesn’t solve the problem to add `lablgtk.cma`
to the compilation command above; the generated executable still
segfaults.

  *)
let _ = GtkMain.Main.init () in
let w = GWindow.window ~width:200 ~height:150 ~title:"hello, world" () in
let _ = w#connect#destroy ~callback:GMain.quit in
let _ = w#show () in
GMain.main()