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: 103376,74b55538385b7366 X-Google-Attributes: gid103376,public From: pascmartin@mail.earthlink.net (Pascal F. Martin) Subject: Re: Ada safety road Was: Which is right ... Date: 1999/06/07 Message-ID: #1/1 X-Deja-AN: 486712566 References: <928083159.436.79@news.remarQ.com> <928174549.336.98@news.remarQ.com> <7iuqkc$ln6$1@nnrp1.deja.com> <928529202.956.79@news.remarQ.com> <928569312.951.42@news.remarQ.com> <7jb1l9$694$1@nnrp1.deja.com> <928703068.617.98@news.remarQ.com> <7jf1ik$8v6$1@nnrp1.deja.com> Content-Type: text/plain; charset=us-ascii X-Trace: cynws01.we.mediaone.net 928773881 24.130.92.251 (Mon, 07 Jun 1999 09:44:41 PDT) Organization: MediaOne-Road Runner, Western Region Mime-Version: 1.0 NNTP-Posting-Date: Mon, 07 Jun 1999 09:44:41 PDT Newsgroups: comp.lang.ada Date: 1999-06-07T00:00:00+00:00 List-Id: In article <7jf1ik$8v6$1@nnrp1.deja.com>, Robert Dewar writes: > In article <928703068.617.98@news.remarQ.com>, > "Vladimir Olensky" wrote: > >> I was just thinking about different aspects of providing some >> general kind of "foolproofness" to program written in Ada in > places where RM >> define program behavior as erroneous. >> I think nobody would like to be on a plane that performed >> erroneous flight >> """' ' ' ^~\_+. >> Anyone would prefer to be accidentally on board of the wrong >> flight instead. > > [...] > > I don't want to be on a plane that executes erroneous code, > but I also don't want the captain to get a message saying > that Constraint_Error was raised at such and such a location :-) I remember that the first Ariane 5 rocket had been lost when an Ada program did hit a runtime check ! The exception was not the cause of the problem (it was a design error), but it made the rocket crash. Sometime, it make sense to ignore errors and continue on. Constraint_Error is for developpers, not for users, and a program cannot be in "debug mode" forevever. -- Pascal F. Martin.