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From: Jan Andres <jandres@gmx.net>
Newsgroups: comp.lang.ada
Subject: Re: Type safety on wikipedia
Date: Sat, 28 Jan 2006 01:48:27 +0000 (UTC)
Organization: home.jan
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Date: 2006-01-28T01:48:27+00:00
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On 2006-01-27, Martin Krischik <krischik@users.sourceforge.net> wrote:
> with Ada.Text_Io;
>
> procedure Access_Test is
>     type Int_Access is access Integer;
>     procedure Deallocate is new Unchecked_Deallocation ....
>
>    P : Int_Access := new Integer;
>    Q : Int_Access := P;
> begin
>     Deallocate (P);
>     Ada.Text_Io.Put_Line(Integer'Image(Q.All));
>  end Access_Test;

Hmm, but aren't all the restrictions on the scope of access values
actually there in order to guarantee type safety, as long as no unsafe
constructs like 'Unchecked_Access are used? Or is
Unchecked_Deallocation itself considered to be such an unsafe construct?
If so, is there any "safe" alternative in Ada that we can use if we
don't have GC?

Of course you could simply avoid such constructs as quoted above but
the downside is that the language will not actually enforce this.

Regards
-- 
Jan Andres <jandres@gmx.net>