[indent=4]
 
uses Gtk
 
class MyWin : Gtk.Window
    mdlg : Gtk.MessageDialog
    const exit_str : string = "Exit ?"
 
    // from a menu item
    def exit_clicked ()
        var e = new Gdk.Event(Gdk.EventType.DELETE)
        this.exit_event(e)
 
    // from Alt-F4 or window toolbar or ...
    def exit_event (E : Gdk.Event) : bool
        var mdlg = new Gtk.MessageDialog (this, Gtk.DialogFlags.DESTROY_WITH_PARENT | Gtk.DialogFlags.MODAL, Gtk.MessageType.QUESTION, Gtk.ButtonsType.YES_NO, this.exit_str)
        if mdlg.run() == Gtk.ResponseType.YES
            Gtk.main_quit()