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 X-Google-Thread: 103376,fee8802cc3d8334d X-Google-Attributes: gid103376,public From: "Jean-Pierre Rosen" Subject: Re: Ada and Java. different behaviour. casting long to int problem. Date: 1999/06/17 Message-ID: <7kaa6o$nr3$2@wanadoo.fr>#1/1 X-Deja-AN: 490583679 Content-Transfer-Encoding: 8bit References: <7jt2c0$vrb@drn.newsguy.com> <7k57vb$1ipf@drn.newsguy.com> <3766650F.705125B7@pwfl.com> <7k64t7$igo$1@its.hooked.net> <7k689a$ci2@drn.newsguy.com> <3766C842.E1EAB60A@pwfl.com> <3766D1CC.D712895E@itools.symantec.com> <7k8nn5$qcb$1@its.hooked.net> <3767E8A2.EF1A0570@itools.symantec.com> <7k8tv3$3gm@drn.newsguy.com> Content-Type: text/plain; charset="iso-8859-1" X-MimeOLE: Produced By Microsoft MimeOLE V4.72.2120.0 X-Complaints-To: abuse@wanadoo.fr X-Trace: wanadoo.fr 929606680 24419 164.138.50.91 (17 Jun 1999 08:04:40 GMT) Organization: Adalog Mime-Version: 1.0 NNTP-Posting-Date: 17 Jun 1999 08:04:40 GMT Newsgroups: comp.lang.ada Date: 1999-06-17T08:04:40+00:00 List-Id: Hyman Rosen a �crit dans le message ... >Looks like it's time to mention again that an unhandled exception >raised by conversion overflow caused the Ariane 5 rocket to go off >course, resulting in its destruction. > Please read the report. The Ariane 501 failure was caused by the *removal* of a necessary check. Ada then diagnosed correctly the error, and did what the specifications required it to do in this case: it made a memory dump which was interpreted by the flight computer as positionnal data. You can't blame the language for doing exactly what was in the specification; the specifications were wrong. Of course, without overflow checking, you would'nt have triggered the incorrect behaviour required by the specification, but I don't think this can be taken as an argument against overflow checking... --------------------------------------------------------- J-P. Rosen (Rosen.Adalog@wanadoo.fr) Visit Adalog's web site at http://perso.wanadoo.fr/adalog