From owner-sc22wg5@open-std.org Wed Dec 3 21:34:32 2008 Return-Path: X-Original-To: sc22wg5-dom7 Delivered-To: sc22wg5-dom7@www2.open-std.org Received: by www2.open-std.org (Postfix, from userid 521) id 27BC1C56CF8; Wed, 3 Dec 2008 21:34:32 +0100 (CET) X-Original-To: sc22wg5@open-std.org Delivered-To: sc22wg5@open-std.org Received: from ppsw-0.csi.cam.ac.uk (ppsw-0.csi.cam.ac.uk [131.111.8.130]) by www2.open-std.org (Postfix) with ESMTP id 6C7D8C4596D for ; Wed, 3 Dec 2008 21:34:30 +0100 (CET) X-Cam-AntiVirus: no malware found X-Cam-SpamDetails: not scanned X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/ Received: from hermes-1.csi.cam.ac.uk ([131.111.8.51]:34993) by ppsw-0.csi.cam.ac.uk (smtp.hermes.cam.ac.uk [131.111.8.150]:25) with esmtpa (EXTERNAL:nmm1) id 1L7yQY-0004KP-0o (Exim 4.70) for sc22wg5@open-std.org (return-path ); Wed, 03 Dec 2008 20:34:30 +0000 Received: from prayer by hermes-1.csi.cam.ac.uk (hermes.cam.ac.uk) with local (PRAYER:nmm1) id 1L7yQY-0006US-7f (Exim 4.67) for sc22wg5@open-std.org (return-path ); Wed, 03 Dec 2008 20:34:30 +0000 Received: from [83.67.89.123] by webmail.hermes.cam.ac.uk with HTTP (Prayer-1.3.1); 03 Dec 2008 20:34:30 +0000 Date: 03 Dec 2008 20:34:30 +0000 From: "N.M. Maclaren" To: sc22wg5 Subject: Re: [ukfortran] (SC22WG5.3715) (j3.2006) Atomic stuff Message-ID: In-Reply-To: <20081203183634.42E63C178DC@www2.open-std.org> References: <20081203025222.12F4BC178E0@www2.open-std.org> <20081203174656.5AF23C4596D@www2.open-std.org> <20081203181454.82657C4596D@www2.open-std.org> <20081203183634.42E63C178DC@www2.open-std.org> X-Mailer: Prayer v1.3.1 Mime-Version: 1.0 Content-Type: text/plain; format=flowed; charset=ISO-8859-1 Sender: owner-sc22wg5@open-std.org Precedence: bulk On Dec 3 2008, Jim Xia wrote: > >Nick, I don't see how that note (5.42) covers my example. Sorry - written in too much haste. It doesn't, if ATOMIC_INTEGER_KIND takes the same space as two INTEGER(KIND=2) variables. > Then it is clobbered by constraint C589, C590, C591 and 4.5.2.3. That does it, though. >Atomic loads and stores on mis-aligned variables are nearly impossible on >many hardwares (The solution to fix up the mis-alignment by either >hardware or OS causes the operation become non-atomic, let along the >performance hit). Yes, but I think that those constraints already exclude it. Regards, Nick Maclaren, University of Cambridge Computing Service, New Museums Site, Pembroke Street, Cambridge CB2 3QH, England. Email: nmm1@cam.ac.uk Tel.: +44 1223 334761 Fax: +44 1223 334679