Re: I do not understand this error...

[John Smith <yoursurrogategod@gmail.com>]

Hello Dmitry,

What is Gtk.Missed?  That does not seem to exist according to the docs:
http://docs.adacore.com/gtkada-docs/gtkada_rm/gtkada_rm/

On Sunday, February 7, 2016 at 3:23:59 AM UTC-5, Dmitry A. Kazakov wrote:
> On 2016-02-07 01:34, John Smith wrote:
> > The the following example is wrong:
> > http://rosettacode.org/wiki/Hello_world/Graphical#Ada
> >
> > If so, then how would you fix this?
> >
> > On Saturday, February 6, 2016 at 6:47:49 PM UTC-5, Jeffrey R. Carter wrote:
> >> On 02/06/2016 03:55 PM, John Smith wrote:
> >>>
> >>> gtk_test.adb:16:04: instantiation error at gtk-handlers.ads:1039
> >>> gtk_test.adb:16:04: subprogram must not be deeper than access type
> >>> gtk_test.adb:17:04: instantiation error at gtk-handlers.ads:437
> >>> gtk_test.adb:17:04: subprogram must not be deeper than access type
> >>
> >> This an accessibility check. It means that it's possible for an
> >> access-to-subprogram value to be copied into a variable which has longer life
> >> than the subprogram. This is not allowed by the language.
> 
> Generic packages from Gtk.Handlers cannot be instantiated in the main 
> procedure, due to accessibility check, as Jeffrey wrote.
> 
> To resolve this move instantiations Handlers and Return_Handles into a 
> separate [library level] package and use this package in the main procedure.
> 
> In GtkAda contributions there are pre-instantiated handlers to deal with 
> gtk program exit. A working example will look like:
> --------------------------------------------
> with Gtk.Label;   use Gtk.Label;
> with Gtk.Window;  use Gtk.Window;
> 
> with Gtk.Main;
> with Gtk.Missed;
> 
> procedure gtk_test is
>     Window : Gtk_Window;
>     Label  : Gtk_Label;
>   begin
>     Gtk.Main.Init;
>     Gtk.Window.Gtk_New (Window);
>     Window.On_Delete_Event (Gtk.Missed.Delete_Event_Handler'Access);
>     Window.On_Destroy (Gtk.Missed.Destroy_Handler'Access);
>     Gtk_New (Label, "Goodbye, World!");
>     Window.Add (Label);
>     Window.Show_All;
>     Gtk.Main.Main;
> end gtk_test;
> -----------------------------------------------
> http://www.dmitry-kazakov.de/ada/gtkada_contributions.htm
> 
> -- 
> Regards,
> Dmitry A. Kazakov
> http://www.dmitry-kazakov.de