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,d154e1596a6ac2d9 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news4.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!nx02.iad01.newshosting.com!newshosting.com!newsfeed.icl.net!newsfeed.fjserv.net!news.tele.dk!news.tele.dk!small.news.tele.dk!not-for-mail Date: Mon, 17 Oct 2005 17:57:48 +0200 From: Poul-Erik Andreasen User-Agent: Debian Thunderbird 1.0.2 (X11/20050817) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Newbie: Task parametering References: <4352ef15$0$28225$5a62ac22@per-qv1-newsreader-01.iinet.net.au> <1129510387.675070.134750@g14g2000cwa.googlegroups.com> In-Reply-To: <1129510387.675070.134750@g14g2000cwa.googlegroups.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Message-ID: <4353c9fc$0$163$edfadb0f@dread11.news.tele.dk> Organization: TDC Totalloesninger NNTP-Posting-Host: 80.166.145.174 X-Trace: 1129564668 dread11.news.tele.dk 163 80.166.145.174:44741 X-Complaints-To: abuse@post.tele.dk Xref: g2news1.google.com comp.lang.ada:5747 Date: 2005-10-17T17:57:48+02:00 List-Id: jimmaureenrogers@worldnet.att.net wrote: > Andrew Price wrote: > >>Hello all, >> >>I need to initialise some tasks with a few parameters when I instantiate >>them. After looking at >>http://www.adaic.com/docs/95style/html/sec_6/6-1-3.html it seems the >>best way to do this is using an access type discriminant to pass a >>record to the tasks. >> >>With that in mind, I created this record type; >> >>type Task_Data is >> record >> Name : aliased String(1..8); >> Period : aliased Duration; >> Repetitions : aliased Integer; >> end record; >> >> >>and then in the main part of my program I use it like this; >> >> type Task_Handle is access A_Task; -- used to point to the task >> Another_Task : Task_Handle; >> type Data_Handle is access Task_Data; -- used to point to its data >> Data_For_Task : Data_Handle; >> >>begin -- The main prog will now spawn three of the above tasks >> >> -- Parameterise the first task and then start it. >> Data_For_Task := new Task_Data; >> Data_For_Task.Name := "Task A "; >> Data_For_Task.Period := 0.5; >> Data_For_Task.Repetitions := 5; >> Another_Task := new A_Task(Data_For_Task); >> >>So while this approach works, I can't help but feel that I'm going about >>this in a 'long winded' way (especially coming from a mostly C background). >> >>Is there are neater way of putting the data into the Task_Data records? >>Or is there an better approach to the whole task parameterisation I >>should consider? >> >>Now is probably a good time to add the disclaimer that this is part of a >>lab work exercise for a course I'm currently undertaking at university. > > > There is a little roblem with your approach. > > It does not actually initialize the task. The task begins running > before the values are set. You are likely to encounter a race > condition with your approach. Where do you get that idea. Before any allocation the access_varible only contain null; PEA