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From: Matthew Heaney <matthew_heaney@acm.org>
Subject: Re: Ada 83 Pointers question
Date: 1999/01/21
Message-ID: <m3u2xk4jtt.fsf@mheaney.ni.net>#1/1
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References: <36A658CA.97438B6@cacd.rockwell.com>
 <36A741BA.E500BC6D@spam.innocon.com>
NNTP-Posting-Date: Thu, 21 Jan 1999 09:25:56 PDT
Newsgroups: comp.lang.ada
Date: 1999-01-21T00:00:00+00:00
List-Id: <comp.lang.ada>

Jeff Carter <spam.carter.not@spam.innocon.com> writes:

> It is perfectly legal Ada 83 to instantiate Unchecked_Conversion to
> convert from System.Address to an access type.

That's being _very_ generous...

> If the result designates the value you want it to, then this should
> work fine for you. However, such an approach is entirely compiler
> dependent. This may not bother you, since you are maintaining the
> compiler.

The issue is whether or not pointers to unconstrained arrays use a dope
vector or not, and whether the pointer points to the dope vector, or to
the array itself.

In general, if you convert from System.Address to an access type, you
better know what you are doing!