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-Thread: 103376,db4f13247a2521f X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!proxad.net!usenet-fr.net!news.enst.fr!not-for-mail From: Jerome Hugues Newsgroups: comp.lang.ada Subject: Re: Intended use of package Ada.Task_Attributes Date: Thu, 5 May 2005 15:33:09 +0000 (UTC) Organization: ENST, France Message-ID: References: <9g3jomw1nprv$.1oustugm8nxot$.dlg@40tude.net> NNTP-Posting-Host: merlin.enst.fr X-Trace: avanie.enst.fr 1115307189 96774 137.194.160.24 (5 May 2005 15:33:09 GMT) X-Complaints-To: usenet@enst.fr NNTP-Posting-Date: Thu, 5 May 2005 15:33:09 +0000 (UTC) User-Agent: slrn/0.9.7.3 (SunOS) Xref: g2news1.google.com comp.lang.ada:10933 Date: 2005-05-05T15:33:09+00:00 List-Id: In article , Steve wrote: > "Jerome Hugues" wrote in message > news:slrnd7k1ct.4m8.hugues@merlin.enst.fr... >> In article <9g3jomw1nprv$.1oustugm8nxot$.dlg@40tude.net>, Dmitry A. >> Kazakov wrote: >>>> implementing implementation-defined task attributes / properties? >>>> >>>> What constitutes a "good use" of this package? >>> >>> Basically the task ID is anything you need. You can then create a hash >>> table to keep pointers to the task specific data global in your system. >>> This will require dynamic handling of the table and also checking if the >>> table contains task data and creating them if necessary. Task_Attributes >>> provides an alternative which might appear more usable in an embedded or >>> real-time system: statically allocated data, faster data access (no hash >>> table search needed) etc. >> >> Except that it is explicitely forbidden by the Ravenscar profile :( >> >> see http://www.adaic.com/standards/rm-amend/html/RM-D-13-1.html >> > > Did I miss something? > > Who said anything about the requirement of following the Ravenscar profile? > > I thought the Ravenscar profiler was a tool that restricted certain > operations that are difficult to prove are safe for safety critical > applications. Which is a small subset of Ada applications. Sorry, I went a bit fast when reacting to Dmitry argument. Given that the Ravenscar profile is a subset of Ada, dedicated to real-time applications, I think it is interesting to think about why it was discarded. If you read the implementation notes of GNAT (for GNU/Linux, see a-tasatt.adb), you'll understand why it is not something one should allow for any real-time system, unless your tool vendor provide strong guarantee for your target. So, I'm not sure it is someone one would consider for any real-time system, be it Ravenscar-compliant or not. -- Jerome