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=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,c2dda499a002ec3c X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-04-11 04:53:07 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news.tele.dk!small.news.tele.dk!128.39.3.168!uninett.no!dax.net!juliett.dax.net!not-for-mail Newsgroups: comp.lang.ada Subject: Re: rendez-vous underlying mechanism References: <3CA2A827.11140295@adaworks.com> From: Ole-Hjalmar Kristensen Message-ID: <7vr8lmiha5.fsf@vlinux.voxelvision.no> User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.1 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 11 Apr 2002 11:52:35 GMT NNTP-Posting-Host: 193.216.12.150 X-Complaints-To: abuse@tele2.no X-Trace: juliett.dax.net 1018525955 193.216.12.150 (Thu, 11 Apr 2002 13:52:35 MET DST) NNTP-Posting-Date: Thu, 11 Apr 2002 13:52:35 MET DST Organization: Tele2 Norway AS Public Access Xref: archiver1.google.com comp.lang.ada:22354 Date: 2002-04-11T11:52:35+00:00 List-Id: "Pat Rogers" writes: > "Kevin Cline" wrote in message > news:ba162549.0204100919.7cfc14dc@posting.google.com... > > "Pat Rogers" wrote in message > news:... > > > > > I was certainly surprised > > > > when I attempted to create a separate task for I/O but found that > > > > all tasks blocked anyway because they were mapped to a single Unix thread. > > > > On that implementation Ada multi-tasking was uselsss for solving > > > > problems routinely handled with Posix threads. > > > > > > Agreed; an undesirable implementation if the option of mapping tasks to > Pthreads > > > was not available, but that's my point -- that was a given implementation > that I > > > don't believe is not the norm today. > > > > It doesn't matter much whether it's the norm. If the language standard > > doesn't guarantee any useful semantics then programs that use the > > Ada tasking model for the aforementioned purpose are not portable > > across compilers. > > If you expect a language standard -- any language standard -- to specify such a > mapping to an operating system implementation you will remain "surprised". Agreed, but it would be reasonable to see a language standard specify that blocking a task would not block the entire program. It's a pity it's not covered in the Ada standard.