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: 103376,9bc0262607f781e9
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2002-06-08 06:39:18 PST
Path: 
 archiver1.google.com!news2.google.com!news1.google.com!newsfeed.stanford.edu!newsfeeds.belnet.be!newsfeed.belnet.be!news.belnet.be!newsfeed.vmunix.org!blackbush.xlink.net!blackbush.de.kpnqwest.net!rz.uni-karlsruhe.de!schlund.de!news.online.de!not-for-mail
From: "Dr. Michael Paus" <paus@ib-paus.com>
Newsgroups: comp.lang.ada
Subject: Re: Making a package safe for use by multiple tasks
Date: Sat, 08 Jun 2002 15:39:16 +0200
Organization: 1&1 Internet AG
Message-ID: <3D020904.1060308@ib-paus.com>
References: <adq0le$2np$1@nets3.rz.RWTH-Aachen.DE> <3D0122FF.F8BD771A@acm.org>
 <2tu3gu4cncgni43ljvrqenis1a6n296vt7@4ax.com>
NNTP-Posting-Host: p5083007c.dip0.t-ipconnect.de
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
X-Trace: news.online.de 1023543557 4701 80.131.0.124 (8 Jun 2002 13:39:17 GMT)
X-Complaints-To: abuse@online.de
NNTP-Posting-Date: 8 Jun 2002 13:39:17 GMT
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US;
 rv:1.0rc1) Gecko/20020417
X-Accept-Language: en-us, en
Xref: archiver1.google.com comp.lang.ada:25537
Date: 2002-06-08T13:39:17+00:00
List-Id: <comp.lang.ada>

Craig Carey wrote:
> 
> On Fri, 07 Jun 2002 21:16:55 GMT, Jeffrey Carter <jrcarter@acm.org>
> wrote:
> 
> 
>>Using access values like this is dangerous, even without trying to bring
>>tasking into the mix. I strongly recommend that you not use access types
>>for your vector processing. Once you do that, it is simple to make your
>>operations Pure, which makes adding tasking very easy, since you need do
>>nothing else.
> 
> 
> What is the name of the software and/or compiler, for which that problem
> was detected ?. I guess that it is not GNAT 3.14+ in Windows and maybe
> not GNAT in some other OSes.

I don't think that Jeffrey Carter had any compiler problem in mind when
he wrote the above statement. The use of access types is dangerous here
because it is difficult to get the algorithm right and because you
encounter all sorts of problems with recursion and tasking. This has
nothing to do with any specific compiler or OS. Just try to figure out
how to extend the concept used for the "+" operator to the computation
of the cross product of two vectors. Try to figure out what happens with
a nested call of this operator.

I also have not seen any statement in this thread which explains what
you are gaining by this access fiddling.

Michael