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=-0.3 required=5.0 tests=BAYES_00, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,7d3cb5920e882220 X-Google-Attributes: gid103376,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit X-FeedAbuse: http://nntpfeed.proxad.net/abuse.pl feeded by 88.191.71.11 Path: g2news1.google.com!news4.google.com!feeder1-2.proxad.net!proxad.net!feeder2-2.proxad.net!nntpfeed.proxad.net!news.netfinity.fr!news.f.de.plusline.net!news-fra1.dfn.de!npeer.de.kpn-eurorings.net!npeer-ng1.kpn.DE!newsfeed.arcor.de!newsspool2.arcor-online.net!news.arcor.de.POSTED!not-for-mail From: "Dmitry A. Kazakov" Subject: Re: Contracted exceptions for Ada Newsgroups: comp.lang.ada User-Agent: 40tude_Dialog/2.0.15.1 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Reply-To: mailbox@dmitry-kazakov.de Organization: cbb software GmbH References: <5947aa62-2547-4fbb-bc46-1111b4a0dcc9@x69g2000hsx.googlegroups.com> <7m9wkymyi5h7.1235e72is9mp9.dlg@40tude.net> <1355376.ahPdGlRDJW@linux1.krischik.com> <1bvj0n3ana6zj.1b1q7na2q2i0a.dlg@40tude.net> <19324822.xTIGfPqStl@linux1.krischik.com> Date: Mon, 10 Dec 2007 09:20:41 +0100 Message-ID: <1ve9sjh3medyv.9gvfdybadnr6.dlg@40tude.net> NNTP-Posting-Date: 10 Dec 2007 09:12:58 CET NNTP-Posting-Host: eb7bce3f.newsspool1.arcor-online.net X-Trace: DXC=Z9Kbe]oJgdSaoembcbF;DQic==]BZ:af^4Fo<]lROoRQ4nDHegD_]RU3XPK2=CTE`[DNcfSJ;bb[UFCTGGVUmh?TLK[5LiR>kgREh:eP1i_VV] X-Complaints-To: usenet-abuse@arcor.de Xref: g2news1.google.com comp.lang.ada:18847 Date: 2007-12-10T09:12:58+01:00 List-Id: On Sun, 09 Dec 2007 20:04:44 +0100, Martin Krischik wrote: > Dmitry A. Kazakov wrote: > >> On Sun, 09 Dec 2007 16:11:13 +0100, Martin Krischik wrote: >> >>> Dmitry A. Kazakov wrote: >>> >>>> (Maybe a wild guess, but this could save Ariane V. A program assumed >>>> Constraint_Error exception free was recompiled for the hardware where >>>> that was not the case.) >>> >>> My understanding is that the system was brought down by an unexpected >>> hardware exception - i.E. one which the CPU's floating point unit >>> generated. >> >> Yes, and that would be detected by the compiler: >> >> function Integer (X : Float) return Integer; >> >> which was contracted as exception-free on one platform will not be on >> another. So the compiler would reject either its implementation that >> raises Constraint_Error or else its use contracted as >> Constraint_Error-free. So the idea. >> >> (Contracted exceptions would mean a damn LOT of work for the compiler >> vendors.) > > I forgot to mention mentioned that they used pragma Suppress to speed thing > up (the old 'pedia article mentioned that). With pragma Suppress in place > the HW-exception was never converted into an Ada-exception. > > Even the best exception handling won't help if you switch it off :-( . See, but you could not switch off the language! (:-)) -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de