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=-0.3 required=5.0 tests=BAYES_00, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!mx02.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: What exactly is the licensing situation with GNAT? Date: Sat, 22 Nov 2014 10:21:27 +0100 Organization: cbb software GmbH Message-ID: <1o96lk3d6rgax.ov1mo3wfhfvh.dlg@40tude.net> References: <19fa65d4-72c9-44ab-b44b-4ea0929c18f2@googlegroups.com> <25731193-c0b5-4ab7-87ff-ba8c6a42cdbd@googlegroups.com> <1se4bvo6gaqft.16cfjaiketlz0$.dlg@40tude.net> <13efsbp4ynti1.1qsb6buqa4a60.dlg@40tude.net> <1lxkqa97hflr0.1c0bm39tzl8ty$.dlg@40tude.net> <2k62zlcocx1l$.1cg687ltl85l9.dlg@40tude.net> <1u2gy6fhz9fpr$.vzj1o4ueae0g$.dlg@40tude.net> Reply-To: mailbox@dmitry-kazakov.de NNTP-Posting-Host: wfRpp7ltpEWhI2na6kgpfA.user.speranza.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: 40tude_Dialog/2.0.15.1 X-Notice: Filtered by postfilter v. 0.8.2 Xref: news.eternal-september.org comp.lang.ada:23634 Date: 2014-11-22T10:21:27+01:00 List-Id: On Fri, 21 Nov 2014 16:12:15 -0600, Randy Brukardt wrote: > "Dmitry A. Kazakov" wrote in message > news:1u2gy6fhz9fpr$.vzj1o4ueae0g$.dlg@40tude.net... >> If notification was done per Windows messages mechanism then certainly yes, >> this is a heavy burden. However usually all notification is just pulsing an >> event associated with the socket. Single pulse event is shared by all >> sockets to wake up a thread that then restarts polling sockets status. I >> don't know how much overhead is in signaling an event. It should not be >> much. > > Event? Windows doesn't have anything like that (the only events I know about > are messages). Now (since NT 4.0? (:-)) but I am not sure) it does: http://msdn.microsoft.com/en-us/library/windows/desktop/ms682396%28v=vs.85%29.aspx > Windows does have some sort of Mutex (forget what they're > called), but I've never paid any attention to them because they are useless > within the Janus/Ada universe. It has two of them. A full-blown mutex (can be system-wide) and a light-weight critical section (local to the process). Full mutex is an expensive thing. Critical section is very fast. > That's because the whole point of a mutex is > to block a thread until something sets the mutex, but that would block the > entire Janus/Ada program. I suppose you could poll one, but you can poll the > socket (or whatever) directly so there's no benefit to having a mutex. Yes -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de