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=unavailable autolearn_force=no version=3.4.4 Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!news.stack.nl!reality.xs3.de!news.jacob-sparre.dk!loke.jacob-sparre.dk!pnx.dk!.POSTED!not-for-mail From: "Randy Brukardt" Newsgroups: comp.lang.ada Subject: Re: Termination of tasks waiting on a protected queue Date: Mon, 19 May 2014 16:49:29 -0500 Organization: Jacob Sparre Andersen Research & Innovation Message-ID: References: <3ab5fcf0-d2a8-4c82-ab51-02b829aebcaa@googlegroups.com> NNTP-Posting-Host: static-69-95-181-76.mad.choiceone.net X-Trace: loke.gir.dk 1400536171 4307 69.95.181.76 (19 May 2014 21:49:31 GMT) X-Complaints-To: news@jacob-sparre.dk NNTP-Posting-Date: Mon, 19 May 2014 21:49:31 +0000 (UTC) X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.5931 X-RFC2646: Format=Flowed; Original X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 Xref: news.eternal-september.org comp.lang.ada:19905 Date: 2014-05-19T16:49:29-05:00 List-Id: wrote in message news:3ab5fcf0-d2a8-4c82-ab51-02b829aebcaa@googlegroups.com... > It has always seemed strange that Ada doesn't seem to have a way to block > on > multiple entries, in line with posix select() or waitformultipleobjects. > I'd be happy > with even just a function that can wait on an array of suspension objects. There was such a proposal for Ada 9x. After much discussion, a report was commissioned from the three user-implementor teams. All three reported that the operation would be much more expensive to implement than it appears on the surface. In particular, the people with hard real-time deadlines could not use any imaginable implementation of the feature -- which would have made it useless to the #1 constituency. The idea was dropped and never has been raised since. I've totally forgotten why that was, but if you (or someone else) could dig up the reports, you could find out why it doesn't work in Ada. (I certainly have a printed copy in a dusty box somewhere, but I'm not motivated to go spelunking for it.) [I wrote one of those three reports, but I have no idea where the original, digital version of our report is. It's definitely not on my current computer. If I could have found it, I could have told you the title of our report, which might have helped you dig it up.] Randy.