From owner-sc22wg5@open-std.org Fri Feb 12 16:37:32 2010 Return-Path: X-Original-To: sc22wg5-dom8 Delivered-To: sc22wg5-dom8@www2.open-std.org Received: by www2.open-std.org (Postfix, from userid 521) id CEB50C3BA17; Fri, 12 Feb 2010 16:37:32 +0100 (CET) X-Original-To: sc22wg5@open-std.org Delivered-To: sc22wg5@open-std.org Received: from mail1.cray.com (mail1.cray.com [136.162.62.100]) by www2.open-std.org (Postfix) with ESMTP id EF392C178DA for ; Fri, 12 Feb 2010 16:37:30 +0100 (CET) Received: from beaver.us.cray.com (beaver.us.cray.com [172.30.74.51]) by mail1.cray.com (8.13.6/8.13.3/gw-5323) with ESMTP id o1CFatdr024597 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Fri, 12 Feb 2010 09:36:55 -0600 (CST) Received: from cfexcas01.americas.cray.com (cfexcas-2.us.cray.com [172.30.74.227]) by beaver.us.cray.com (8.13.8/8.13.3/hub-5273) with ESMTP id o1CFagG3024910; Fri, 12 Feb 2010 09:36:53 -0600 Received: from fortran.us.cray.com (172.31.19.200) by cfexcas01.americas.cray.com (172.30.74.226) with Microsoft SMTP Server (TLS) id 8.1.393.1; Fri, 12 Feb 2010 09:27:51 -0600 Message-ID: <4B75737C.7000906@cray.com> Date: Fri, 12 Feb 2010 09:27:56 -0600 From: Bill Long Reply-To: Organization: Cray Inc. User-Agent: Thunderbird 2.0.0.23 (Macintosh/20090812) MIME-Version: 1.0 To: Malcolm Cohen Cc: WG5 Subject: Re: [ukfortran] (SC22WG5.4174) (j3.2006) Urgent: letter ballot on interps References: <20100201122928.54FB8C178E4@www2.open-std.org><20100210005356.4ABF5C3BA23@www2.open-std.org> <20100210185846.34028C178DA@www2.open-std.org> <32C1F39D51964BCAB7EB9BAF77B2F8CC@Marucomputer> In-Reply-To: <32C1F39D51964BCAB7EB9BAF77B2F8CC@Marucomputer> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Cray-VirusStatus: clean Sender: owner-sc22wg5@open-std.org Precedence: bulk Malcolm Cohen wrote: > Bill Long wrote: >> N.M. Maclaren wrote: >>> On Feb 10 2010, Bill Long wrote: >>>> Comment for F03/0039 - HYPOT() >>>> > > No, there is no temptation and no possibility for confusion. > > That is because the Note in question does not exist in F08. We deleted it > specifically because it created more confusion than enlightenment. > Of course, you are right. I was looking a a printed 09-007r1 version at the time. Sorry about that. However, I believe I should have made another comment on this interp stronger. I said -------------- Further, instead of somewhat obscure HYPOT = SQRT(-1.0) why not be clear about the intent and write HYPOT = IEEE_VALUE(X, IEEE_QUIET_NAN) --------------- More than "obscure", the proposed code is not even legal. The SQRT function explicitly requires that a real argument be >= 0, so SQRT(-1.0) has no interpretation in the standard. The expected outcome of trying to compile this example would be a hard error at compile time. Even more reason to go with the alternative, which is not only valid code, but effectively self-documenting, and does exactly what is desired. (That said, I still would prefer no edit at all.) Cheers, Bill -- Bill Long longb@cray.com Fortran Technical Support & voice: 651-605-9024 Bioinformatics Software Development fax: 651-605-9142 Cray Inc./Cray Plaza, Suite 210/380 Jackson St./St. Paul, MN 55101