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From: Adam Beneschan <adam@irvine.com>
Newsgroups: comp.lang.ada
Subject: Re: Preventing Unchecked_Deallocation?
Date: Mon, 6 Feb 2012 08:05:22 -0800 (PST)
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Date: 2012-02-06T08:05:22-08:00
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On Feb 6, 4:52=A0am, Julian Leyh <jul...@vgai.de> wrote:
> On 5 Feb., 17:42, Simon Belmont <sbelmont...@gmail.com> wrote:
>
> > package ud is
> > =A0 function Get return not null access Integer;
> > end ud;
>
> > package body ud is
> > =A0 type Int_Ptr is access all Integer;
> > =A0 o : Int_Ptr :=3D new Integer'(42);
>
> use o : constant Int_Ptr :=3D ....

Ummm, no.  All that does is prevent the variable "o" from being
modified inside the body of UD.  That means that if Free is an
instance of Unchecked_Deallocation, the body of UD can't call

   Free (o);

but that doesn't prevent

   x :=3D o;       -- where x is a variable
   Free (x);

or

   x :=3D Get;
   Free (x);

And "o" will point to a non-existing object.

                            -- Adam