Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!news.dougwise.org!nntpfeed.proxad.net!proxad.net!feeder1-1.proxad.net!198.186.194.247.MISMATCH!news-out.readnews.com!transit3.readnews.com!postnews.google.com!g3g2000prf.googlegroups.com!not-for-mail From: lewbloch Newsgroups: comp.lang.java.programmer,comp.lang.c Subject: Re: Arithmetic overflow checking Date: Wed, 13 Jul 2011 12:16:22 -0700 (PDT) Organization: http://groups.google.com Lines: 65 Message-ID: References: <36bp17tf79bhbd6hovf9srhmcs1jh1c040@4ax.com> <693db00d-83be-4830-a1fc-262d9d34d672@z15g2000pre.googlegroups.com> <9d33ce51-1f6a-4782-8098-a051456532ca@m6g2000prh.googlegroups.com> <8vlr17d90u9cb63hf64hhstaoamdgsb5je@4ax.com> NNTP-Posting-Host: 172.19.63.131 Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: posting.google.com 1310584582 10758 127.0.0.1 (13 Jul 2011 19:16:22 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Wed, 13 Jul 2011 19:16:22 +0000 (UTC) Complaints-To: groups-abuse@google.com Injection-Info: g3g2000prf.googlegroups.com; posting-host=172.19.63.131; posting-account=CP-lKQoAAAAGtB5diOuGlDQk0jIwmH0T User-Agent: G2/1.0 X-Google-Web-Client: true X-Google-Header-Order: ASELCHRU X-HTTP-UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.41 Safari/535.1,gzip(gfe) Xref: x330-a1.tempe.blueboxinc.net comp.lang.java.programmer:6169 comp.lang.c:8249 On Jul 13, 10:38=A0am, Gene Wirchenko wrote: > On Tue, 12 Jul 2011 16:09:04 -0700 (PDT), lewbloch > > > > > > > > > > wrote: > >Gene Wirchenko wrote: > >> lewbloch wrote: > >>> Martin Gregorie wrote: > > >> [snip] > > >>>> [1] The instrument causing the problem was an unmodified Ariane 4 SR= I > >>>> which raised an out-of-limits exception when the normal Ariane 5 > >>>> trajectory exceeded a permitted Ariane 4 horizontal velocity limit. = =A0 > > >> =A0 =A0 =A0...the Ariane 5 having more powerful engines. > > >>> In other words, this was a case where there *was* an out-of-range > >>> exception, thus it makes the exact opposite point to the one Gene > >>> presumably wanted to support. > > >> =A0 =A0 =A0The data I read was that the exception was not handled. =A0= IIRC, > >> debugging got interpreted as navigational data. > >Precisely. =A0There was an exception, and it was not handled. =A0Having > >the exception was not enough. > > =A0 =A0 =A0No surprise there. =A0Most of us understand that exceptions ha= ve to > be handled as well as thrown. > Apparently it was a surprise to the Ariane 5 folks. But you brought up the case history in the first place. What was the point if not that exceptions need to be handled? Isn't the problem with the rocket exactly that exceptions weren't handled, despite your attempt to palm that off as obvious? Or are you just shifting ground now that your apparent original point turns out not to be supported by the Ariane failure? It certainly was not that overflow exceptions are good all by themselves, since that didn't help the rocket in question. The lesson I derive is that nothing is too simple, trivial or obvious to overlook. Whether it's metric vs. English system of length that makes one miss Mars, or failure to handle an exception that makes a rocket blow up, despite that *obviously* one must use consistent units, and *obviously* one must handle exceptions when thrown, we still need to be diligent about such "obvious" matters. So put aside your pseudo-condescension and let's learn the lessons these case histories teach us. -- Lew