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: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: About protected objects: entries with barriers depending on external data = bad practice ? Date: Sun, 12 Nov 2017 08:32:11 +0100 Organization: Aioe.org NNTP Server Message-ID: References: NNTP-Posting-Host: MajGvm9MbNtGBKE7r8NgYA.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 X-Notice: Filtered by postfilter v. 0.8.2 Content-Language: en-US Xref: feeder.eternal-september.org comp.lang.ada:48834 Date: 2017-11-12T08:32:11+01:00 List-Id: On 2017-11-12 06:23, reinert wrote: > Assume a protected entry with a barrier depending on external data - > and it is waiting for its barrier to become true. It must be > laborious to check the barrier depending on something "far-far away"? > How is this checking done in practice? The entry waits for other > entries, procedures or functions and when they arrive, it may start > before them? Or something more efficient? Barrier is evaluated only when required to. E.g. in the case of a protected object after you leave an object's procedure or entry. Updates from outside are most likely ignored. > Letting barriers depend on external data = asking for trouble? Well, most of the time. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de