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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,9ae4660d46953150 X-Google-Attributes: gid103376,public From: Michael Pickett Subject: Re: Enhancement needed (was strange record size ?) Date: 2000/09/13 Message-ID: #1/1 X-Deja-AN: 669782289 X-NNTP-Posting-Host: norvu.demon.co.uk:158.152.205.227 Sender: Michael Pickett References: <0$9CsHAKbiv5Ewg1@ntlworld.com> <39beb5c7.17576629@news.demon.co.uk> X-Complaints-To: abuse@demon.net X-Trace: news.demon.co.uk 968964306 nnrp-07:26537 NO-IDENT norvu.demon.co.uk:158.152.205.227 Organization: Norvu MIME-Version: 1.0 Newsgroups: comp.lang.ada Date: 2000-09-13T00:00:00+00:00 List-Id: In article <39beb5c7.17576629@news.demon.co.uk>, John McCabe writes >Michael Pickett wrote: > ><..snip..> > >>...Robert may have misunderstood my intentions... > >Given my experience of Robert's interpretations, I think that your >hypothesis is likely to be entirely correct! One has to take the rough with the smooth. :-) > >>* Implementation Advice is a useful mechanism for persuading an >>implementor to adopt (or avoid) a particular approach where it would be >>inappropriate to introduce a normative clause. (Unfortunately, the >>Standard does not provide any background on what qualifies a clause to >>be a recommendation rather than a requirement.) > >I may be missing the point here, but I believe IA are guidelines as to >the way a compiler would be expected to do things, but none of these >are requirements. The RM however does identify Implementation >Requirements sections. I am inclined to share your beliefs. The point is, I think, that code that relies on Implementation Requirements is portable, at least to the extent that that is practical, but code that relies on Implementation Advice is only portable to the extent that all compilers under consideration follow that advice. Relying on Implementation Advice being followed is a calculated risk. Relying on Implementation Advice NOT being followed, as appeared to be the case at the start of this exchange, is an even greater risk, even though there may be compilers in this category. My concern in following up this posting was that there may be examples of where only by assuming that Implementation Advice has been taken (and so by taking a calculated risk) is some particular useful effect achievable. I don't know that there are any such examples, - I hope there aren't any - but if there are, I hope someone will bring them forward rather than simply live with the risk. -- --Michael--