Re: Issue with GNAT GPL 2009 and GtkAda

[Stephen Leake <stephen_leake@stephe-leake.org>]

Stephen Leake <stephen_leake@stephe-leake.org> writes:

> 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. 

Another thought: whenever I have trouble with anonymous access types,
I replace them with the corresponding named access type, and the
problem goes away. That may indicate a conmpiler bug, but I've always
had to much to do to find out.

In this case, that means editing the GtkAda sources, which is less
than ideal.

-- 
-- Stephe