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From: dewar@cs.nyu.edu (Robert Dewar)
Newsgroups: comp.lang.ada
Subject: Re: C++ to Ada95, help please
Date: 24 Mar 1995 16:24:34 -0500
Organization: Courant Institute of Mathematical Sciences
Message-ID: <3kvdai$kjk@gnat.cs.nyu.edu>
References: <3kjd2m$d3t@jerry.rb.icl.co.uk> <D5tIGu.Cn6@inmet.camb.inmet.com>
 <D5w7z1.8n5@ss3.magec.com>
NNTP-Posting-Host: gnat.cs.nyu.edu
Date: 1995-03-24T16:24:34-05:00
List-Id: <comp.lang.ada>

Why wasn't pragma Unchecked_Union included in Ada 95?

Really two reasons:

First: it simply wasn't thought of until very recently. Mitch Gart started
a conversation on this issue quite recently, and the suggestion of
pragma Unchecked_Union came out of these discussions. I still wouldn't
regard the design as solid enough to even semi-standardize without more
perusal and experience.

Second: there is a limit on how far it is reasonable to go in the definition
of such language interface details. For one thing, an accurate description of
them depends on the semantics of the other language, so it gets quite tricky.

Third (3 of 2 :-) the Unchecked_Union feature is really rather unpleasant
as a full blown language feature, and putting it in the Ada RM would perhaps
give it TOO much status. There is nothing to stop this being used in Ada
programs quite independently of C (except good taste!)