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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Finalization of static package variables
Date: Fri, 11 May 2007 14:26:37 -0400
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2007-05-11T14:26:37-04:00
List-Id: <comp.lang.ada>

Manuel Collado <m.collado@lml.ls.fi.upm.es> writes:

> But an access variable can refer to a static variable. Is the following
> Ada95 code schema legal?

It is erroneous, which is the Ada term for "wrong, and will cause
totally unpredictable behavior at run time."  Most likely,
you will corrupt the heap data structures if you try to free
objects that are not heap allocated.

Note that if you erase the "Dispose", then Edit will be finalized when
program is done.

>...What about Ada200x (or just Ada, if you want)?

Same answer.

> It seems to work in GNAT-3.15p (it lets finalize 'Edit'), but ...
>
> -------------------------------------------------
> package body View_Editor is
>
>    Edit: aliased Dialog_Type :=
>       Dialog (420, 350, "Conversion Rates", 'Q', Main_Font);
>
> [...snipped...]
>
>    procedure Editor_Destroy is
>       type Dialog_Access is access all Dialog_Type;
>       procedure Dispose is
>          new Ada.Unchecked_Deallocation (
>          Object => Dialog_Type,
>          Name   => Dialog_Access );
>       Pointer: Dialog_Access := Edit'access;
>    begin
>       Dispose (Pointer);
>    end Editor_Destroy;
>
> end View_Editor;

- Bob