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Date: 9 Sep 93 14:59:06 GMT
From: news.crd.ge.com!e7sa!groleau@uunet.uu.net  (Wes Groleau x1240 C73-8)
Subject: Re: Generic Pointer Type
Message-ID: <CD3DMI.JJA@crdnns.crd.ge.com>
List-Id: <comp.lang.ada>

In article <EMERY.93Sep8133649@goldfinger.mitre.org> emery@goldfinger.mitre.org
 (David Emery) writes:
>There is no guarantee *within the language* that any unchecked
>conversion will have any meaning.  In particular, there are systems
>where you *cannot* convert between arbitrary access types in any
>meaningful sense.  For instance, access to scalar may be the address
>of the object, but access to array may be a structure holding the
>first index, length and address of the first element.  .......

This reminds me of another mistake made by many:  doing an unchecked conversion
between an access type for an object and the address of an object of the same
type.  Even if access types are addresses (they USUALLY are...) the access to
an array is often the address of a structure like the one David mentioned,
while the address of the array is actually the address of the array.