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Newsgroups: comp.lang.ada
Subject: Re: Issue with GNAT GPL 2009 and GtkAda
References: <4A414EBB.8060204@free.fr>
From: Stephen Leake <stephen_leake@stephe-leake.org>
Date: Wed, 24 Jun 2009 06:15:02 -0400
Message-ID: <uk532lyzd.fsf@stephe-leake.org>
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Date: 2009-06-24T06:15:02-04:00
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Damien Carbonne <damien.carbonne@free.fr> writes:

> When compiling a program I had written to GNAT GPL 2009 on Linux and
> Windows, I met a problem with the usage of Gtk.Tree_Model.Foreach.
>
> I wrote a relatively small program (unfortunately, still quite long)
> that reproduces the problem (attached in the end).

This looks like a compiler bug to me. However, GNAT 6.2.1 on Windows
reports the same access violation.

> I wonder if this is a bug in
>    1) my program,
>    2) GtkAda or
>    3) GNAT GPL 2009.
> What surprises me is that it was quite hard to reproduce this problem.
> Most other examples I wrote with Foreach worked very well.
> I don't know how GNAT handles accessibility rules.

Since the access object being dereferenced is in a package level
variable, it should not be possible to get an access violation.

> I wonder if the problem is not related to the usage of Interfaces ?
> I did not try yet to change the program so that it can work, but other
> examples I wrote were quite similar, except that they did not use
> interfaces. I'll check, but do you have any idea on this issue ?

I don't see why interfaces should affect accessibility. 

If you post a variant that works with GNAT 2009, I can try it with
6.2.1.

I suggest you report this to AdaCore.

-- 
-- Stephe