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From: bobduff@world.std.com (Robert A Duff)
Subject: Re: limited/non-limited in Ada95
Date: 1997/10/21
Message-ID: <EIFE35.377@world.std.com>#1/1
X-Deja-AN: 284936063
References: <3442C2A3.3781@bix.com> <ufhgaghueo.fsf@synquiry.com>
 <3449390f.142507@SantaClara01.news.InterNex.Net>
 <mheaney-ya023680001810971645020001@news.ni.net>
Organization: The World Public Access UNIX, Brookline, MA
Newsgroups: comp.lang.ada
Date: 1997-10-21T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <mheaney-ya023680001810971645020001@news.ni.net>,
Matthew Heaney <mheaney@ni.net> wrote:
>declare
>   D : aliased DT;
>   O : T (D'Unchecked_Access);
>begin
>
>Will that do what you want?

The problem is that as soon as you use 'Unchecked_Access, you lose the
nice properties of access discriminants for preventing dangling
references.  Given the above, somebody might assign "Global := O;",
creating a dangling ref, whereas that won't happen if it were an access
discrim.

- Bob