Date: Tue, 16 Sep 2003 11:31:37 +0100
To: lablgtk at kaba.or.jp
Subject: Memory handling bug: cannot access fields in a combo box belonging to a dialog which has been destroyed
Message-ID: <20030916103137.GA25181 at redhat.com>
Mime-Version: 1.0
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From: Richard Jones <rich at annexia.org>


The following program demonstrates a bug (I think) in the memory
handling of lablgtk2 (tested against lablgtk2-20030828 on Linux and
Windows).

The program creates a dialog containing a combo box, then destroys the
dialog, and tries to retrieve the text from the combo box.

This fails with the following Gtk error:

Fatal error: exception Glib.Critical("GLib-GObject", "file gobject.c: line 1319 (g_object_ref): assertion `G_IS_OBJECT (object)' failed")

and the program aborts.

The entry widget in the combo box shouldn't, of course, be deleted
until all references held by the program have been destroyed.

Rich.

----------------------------------------------------------------------
(* Test reading strings from a combo box in a dialog which has been destroyed.
 * By Richard W.M. Jones <rich@annexia.org>
 * $Id: dialogdestroy.ml,v 1.1 2003/09/16 10:26:03 rich Exp $
 *
 * Compile with:
 * ocamlopt -w s -I +lablgtk2 lablgtk.cmxa gtkInit.cmx dialogdestroy.ml \
 *   -o dialogdestroy
 *)

let () =
  let dialog = GWindow.dialog () in
  dialog#connect#destroy ~callback:GMain.Main.quit;
  dialog#set_position `CENTER;

  let entry = GEdit.combo ~value_in_list:true ~allow_empty:false
		~popdown_strings: ["option1"; "option2"; "option3"]
		~packing:dialog#vbox#pack () in

  let ok_button = GButton.button ~label:"Test"
		    ~packing:dialog#action_area#add () in
  ok_button#connect#clicked ~callback:dialog#destroy;

  dialog#show ();
  GMain.Main.main ();

  (* Dialog has been destroyed here. Try to get the text from the combo. *)
  let text = entry#entry#text in
  prerr_endline ("text is: " ^ text)
----------------------------------------------------------------------

-- 
Richard Jones. http://www.annexia.org/ http://freshmeat.net/users/rwmj
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