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=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,dd6622a305422ade X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-09-10 05:13:05 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed1.earthlink.net!newsfeed.earthlink.net!newsmaster1.prod.itd.earthlink.net!newsread2.prod.itd.earthlink.net.POSTED!not-for-mail Message-ID: <3B9CA250.88DB9DF1@earthlink.net> From: "Marc A. Criley" Organization: Quadrus Corporation X-Mailer: Mozilla 4.73 [en] (X11; U; Linux 2.2.14-5.0 i686) X-Accept-Language: en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Suggestion for Ada 0X - "Complete" Record Rep Clauses References: <87sndvsiqm.fsf@deneb.enyo.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Mon, 10 Sep 2001 12:13:35 GMT NNTP-Posting-Host: 158.252.123.33 X-Complaints-To: abuse@earthlink.net X-Trace: newsread2.prod.itd.earthlink.net 1000124015 158.252.123.33 (Mon, 10 Sep 2001 05:13:35 PDT) NNTP-Posting-Date: Mon, 10 Sep 2001 05:13:35 PDT X-Received-Date: Mon, 10 Sep 2001 05:09:53 PDT (newsmaster1.prod.itd.earthlink.net) Xref: archiver1.google.com comp.lang.ada:12980 Date: 2001-09-10T12:13:35+00:00 List-Id: Florian Weimer wrote: > > "Chris Miller" writes: > > > Record representation clauses (LRM13.5.1) allow the locations for the > > components of a record to be specified, but there is no way to ensure that > > the location for each and every field is specified. If you do not specify > > the location for a component then the compiler can put it anywhere. This is > > generally not what is wanted, if a rep clause is used then typically the > > location of all fields will need to be specified. > > Specifying the representation only partially could be used in some > contexts, for example to rearrange some components so that they appear > in a single cache line. We found that records having "partial rep specs" could have the non-specified components layed out using quite different approaches by different compilers (porting from Alsys Ada 83 to GNAT Ada 95). There's nothing wrong with that, it simply reinforces the notion that one has to know what they're doing and be aware of potential pitfalls when porting. Marc A. Criley Senior Staff Engineer Quadrus Corporation www.quadruscorp.com