From owner-sc22wg5+sc22wg5-dom8=www.open-std.org@open-std.org Thu Jul 3 12:14:43 2014 Return-Path: X-Original-To: sc22wg5-dom8 Delivered-To: sc22wg5-dom8@www.open-std.org Received: by www.open-std.org (Postfix, from userid 521) id 82CFF3587B1; Thu, 3 Jul 2014 12:14:43 +0200 (CEST) Delivered-To: sc22wg5@open-std.org Received: from ppsw-40.csi.cam.ac.uk (ppsw-40.csi.cam.ac.uk [131.111.8.140]) by www.open-std.org (Postfix) with ESMTP id B62053572C3 for ; Thu, 3 Jul 2014 12:14:38 +0200 (CEST) X-Cam-AntiVirus: no malware found X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/ Received: from hermes-1.csi.cam.ac.uk ([131.111.8.51]:49299) by ppsw-40.csi.cam.ac.uk (smtp.hermes.cam.ac.uk [131.111.8.156]:25) with esmtpa (EXTERNAL:nmm1) id 1X2e2H-0002rN-lQ (Exim 4.82_3-c0e5623) (return-path ); Thu, 03 Jul 2014 11:14:37 +0100 Received: from prayer by hermes-1.csi.cam.ac.uk (hermes.cam.ac.uk) with local (PRAYER:nmm1) id 1X2e2H-0004Iq-LA (Exim 4.72) (return-path ); Thu, 03 Jul 2014 11:14:37 +0100 Received: from [131.111.56.53] by old-webmail.hermes.cam.ac.uk with HTTP (Prayer-1.3.5); 03 Jul 2014 11:14:37 +0100 Date: 03 Jul 2014 11:14:37 +0100 From: "N.M. Maclaren" To: Van.Snyder@jpl.nasa.gov Cc: sc22wg5 Subject: Re: [ukfortran] (SC22WG5.5294) Did we intend to prohibit this? Message-ID: In-Reply-To: <20140702232501.1F2EE35877B@www.open-std.org> References: <20140702232501.1F2EE35877B@www.open-std.org> X-Mailer: Prayer v1.3.5 Mime-Version: 1.0 Content-Type: text/plain; format=flowed; charset=ISO-8859-1 Sender: owner-sc22wg5@open-std.org Precedence: bulk On Jul 3 2014, Van Snyder wrote: >As far as I can tell from looking at 7.1.12, the only function from >IEEE_Arithmetic that's allowed in a constant expression is >IEEE_Selected_Real_Kind. > >Did we intend to prohibit all the others? > >Is there a problem with admitting the inquiry functions, and admitting >the others provided their arguments are constant expressions? One issue that would have to be considered is what requirements we would place on compile- and run-time options to control the modes. IEEE 754 remains a very assembler-level specification, does not map well even to C, and its arithmetic model is seriously incompatible with Fortran's. This is probably resolvable, but isn't just a matter of relaxing the restrictions. I, for one, lack the enthusiasm to tackle this. Regards, Nick.