From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=unavailable autolearn_force=no version=3.4.4 Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: "J-P. Rosen" Newsgroups: comp.lang.ada Subject: Re: for X'Address use - and Volatile Date: Thu, 1 Sep 2016 10:12:28 +0200 Organization: A noiseless patient Spider Message-ID: References: <7595494c-3398-4fd9-ab4b-80a79383ae33@googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Injection-Date: Thu, 1 Sep 2016 08:12:32 -0000 (UTC) Injection-Info: mx02.eternal-september.org; posting-host="45bffd6a911624777cad79aac3181090"; logging-data="15831"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19ZT7tMJI7htXfjb6qpnzIv" User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 In-Reply-To: Cancel-Lock: sha1:S3Qb0bjU54KbkjkGdNESvI6ECSM= Xref: news.eternal-september.org comp.lang.ada:31671 Date: 2016-09-01T10:12:28+02:00 List-Id: Le 31/08/2016 à 21:36, Randy Brukardt a écrit : >> Consider: >> >X : Integer; >> >Y : Integer; >> >for Y'Address use X'Address; >> > >> >The above is a simple overlay, typically used for under-the-table type >> >conversions. > Ada does not now, nor ever has, officially supported overlays. Such code > might work on a particular implementation, but it's not portable (even to > another version of the same compiler). > > Indeed, address clauses ought to be avoided for all but their intended > purpose (mapping to hardware registers); for other purposes, better > solutions exist (Unchecked_Conversion, Address_to_Access_Conversions, etc.) Shameless plug: and this can be detected in AdaControl: check representation_clauses (overlay); -- J-P. Rosen Adalog 2 rue du Docteur Lombard, 92441 Issy-les-Moulineaux CEDEX Tel: +33 1 45 29 21 52, Fax: +33 1 45 29 25 00 http://www.adalog.fr