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: 103376,108a618b460a8c87 X-Google-Attributes: gid103376,public From: Martin Dowie Subject: Re: Tasking differences Date: 2000/07/12 Message-ID: <396C504F.EF3F332A@baesystems.com>#1/1 X-Deja-AN: 645425687 Content-Transfer-Encoding: 7bit References: <3969B65A.46942054@baesystems.com> <8ke8ao$rs3$1@nnrp1.deja.com> <396AECA4.30B03835@baesystems.com> <8kgk79$khp$1@nnrp1.deja.com> Content-Type: text/plain; charset=us-ascii X-Trace: 12 Jul 2000 12:00:09 GMT, stnp2927.stanmre.gecm.com MIME-Version: 1.0 Newsgroups: comp.lang.ada Date: 2000-07-12T00:00:00+00:00 List-Id: i should have been clearer - yes the output is non-deterministic, but the outcome that wasn't 'expected' was that it hangs when attempting a second 'select ... else' - the non-deterministic output was entirely expected! on removal of timer variables, pragma priorities and most text_io, except from the 'stop' subprogram that is called by the main program, we still see the same 'hanging'/'non-hanging' differences. the best guess so far is that there is a bug in the behaviour of 'select ... else' statements and delays (thanks pete). Robert Dewar wrote: > > In article <396AECA4.30B03835@baesystems.com>, > Martin Dowie wrote: > > sorry, but I can't see why there should be any difference in > *results* of the > > two - if they were so different, why does GNAT produce the > same results for both > > versions? I understand that the scheduling of the 2 tasks can > change given the > > differences, but in this case I don't see why that should > affect the outcome. > > Running code locked instead of unlocked makes a big difference > in the set of possible outcomes, the fact that with one > particular scheduling discipline you see no differences proves > nothing about the possible non-deterministic set of outcomes! > > Sent via Deja.com http://www.deja.com/ > Before you buy. -- The views expressed here are personnal and not those of BAE Systems.