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!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail From: "J-P. Rosen" Newsgroups: comp.lang.ada Subject: Re: Finalization of library level tasks Date: Wed, 18 Apr 2018 13:33:48 +0200 Organization: Adalog Message-ID: References: <702e2422-a93f-4200-9749-5122c3d0f899@googlegroups.com> <04f19a56-7fab-416e-8ec0-b9a73e239e90@googlegroups.com> NNTP-Posting-Host: vtydEJu0RziDZHka7ZZ6bg.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Complaints-To: abuse@aioe.org User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 Openpgp: preference=signencrypt X-Notice: Filtered by postfilter v. 0.8.3 Content-Language: fr Xref: reader02.eternal-september.org comp.lang.ada:51581 Date: 2018-04-18T13:33:48+02:00 List-Id: Le 18/04/2018 à 11:58, Dmitry A. Kazakov a écrit : > can be emulated using Callable on the helper task: > >    task Helper is >       entry Never; >    end Helper; > >    task body Helper is >    begin >       select >          accept Never; >       or terminate; >       end select; >    end Helper; > >    task body Worker_Task is >    begin >       while Helper'Callable loop >          ... -- Do something >       end loop; >    end Worker_Task; > > When Helper and Worker_Task have same master then Worker_Task can break > finalization deadlock by looking at the Helper. Won't work. Please read 9.3(6/1): the open terminate_alternative is selected if and only if the following conditions are satisfied: - The task depends on some completed master; and - Each task that depends on the master considered is either already terminated or similarly blocked at a select_statement with an open terminate_alternative. Since Worker_Task and Helper depend on the same master, and Worker_Task is still busy, Helper won't select the terminate alternative, and will be still Callable. -- J-P. Rosen Adalog 2 rue du Docteur Lombard, 92441 Issy-les-Moulineaux CEDEX Tel: +33 1 45 29 21 52, Fax: +33 1 45 29 25 00 http://www.adalog.fr