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: 103376,4bd6ca8f7a1eb225
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Received: by 10.68.16.106 with SMTP id f10mr5739581pbd.8.1322787521598;
        Thu, 01 Dec 2011 16:58:41 -0800 (PST)
MIME-Version: 1.0
Path: 
 lh20ni54821pbb.0!nntp.google.com!news1.google.com!goblin1!goblin.stu.neva.ru!news.tornevall.net!news.jacob-sparre.dk!pnx.dk!jacob-sparre.dk!ada-dk.org!.POSTED!not-for-mail
From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Class with task destructor
Date: Thu, 1 Dec 2011 18:57:22 -0600
Organization: Jacob Sparre Andersen Research & Innovation
Message-ID: <jb97pk$bvb$1@munin.nbi.dk>
References: <30604696.94.1322013045135.JavaMail.geo-discussion-forums@yqzz20>
 <rub7mpaqj3m0$.edx48uwzhacd.dlg@40tude.net> <m2r50z8az4.fsf@pushface.org>
 <24938373.1788.1322615481874.JavaMail.geo-discussion-forums@yqjo5>
 <c27dbc9a-fa2e-4ecb-a81f-fe5f8915be3d@h42g2000yqd.googlegroups.com>
 <ey516bovprzb$.1tjszfc528chj$.dlg@40tude.net> <jb6i43$58u$1@munin.nbi.dk>
 <jb76qg$348$1@dont-email.me> <wccliqwdku1.fsf@shell01.TheWorld.com>
NNTP-Posting-Host: static-69-95-181-76.mad.choiceone.net
X-Trace: munin.nbi.dk 1322787444 12267 69.95.181.76 (2 Dec 2011 00:57:24 GMT)
X-Complaints-To: news@jacob-sparre.dk
NNTP-Posting-Date: Fri, 2 Dec 2011 00:57:24 +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: news1.google.com comp.lang.ada:19300
Date: 2011-12-01T18:57:22-06:00
List-Id: <comp.lang.ada>

"Robert A Duff" <bobduff@shell01.TheWorld.com> wrote in message 
news:wccliqwdku1.fsf@shell01.TheWorld.com...
> "J-P. Rosen" <rosen@adalog.fr> writes:
>
>> Put an entry (say "Termination_Wait") in the waited task, and never
>> accept it. Call Termination_Wait from the waiting task. When the waiting
>> task receives Tasking_Error, the waited task is terminated (well,
>> completed, but that should be close enough).
>
> I don't think it's close enough.  It is impossible to actually
> free things before the task is really terminated.  The task is
> doing finalization between completion and termination, and that
> could refer to discriminants.  And even if there's no finalization
> present, the task is still using its stack, which had better not
> be freed.

I agree, but I note that J-P's suggestion at least provides a way to delay 
polling until the task is completed. Most tasks don't have complex 
finalization, so they don't have to stay for a long time in the completed 
state. (Although I'd have to go look up the exact details as to when a 
completed task becomes terminated.

I'll note that I became aware of this need to poll for 'Terminated because 
of various bug reports on ACATS tests involving tasks. Several of them had 
to be fixed by adding such polling before checking the results of the test. 
(And a lot of them already had such polling.) It's hard to avoid in Ada as 
it stands.

                                      Randy.