From owner-sc22wg5@open-std.org Tue Dec 9 03:49:15 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 9F2C4C178E5; Tue, 9 Dec 2008 03:49:15 +0100 (CET) X-Original-To: sc22wg5@open-std.org Delivered-To: sc22wg5@open-std.org Received: from sca-es-mail-2.sun.com (sca-es-mail-2.Sun.COM [192.18.43.133]) by www2.open-std.org (Postfix) with ESMTP id 900B9C178D6 for ; Tue, 9 Dec 2008 03:49:13 +0100 (CET) Received: from fe-sfbay-09.sun.com ([192.18.43.129]) by sca-es-mail-2.sun.com (8.13.7+Sun/8.12.9) with ESMTP id mB92n8H6014611 for ; Mon, 8 Dec 2008 18:49:10 -0800 (PST) Received: from conversion-daemon.fe-sfbay-09.sun.com by fe-sfbay-09.sun.com (Sun Java System Messaging Server 6.2-8.04 (built Feb 28 2007)) id <0KBL00E01908B000@fe-sfbay-09.sun.com> (original mail from Robert.Corbett@Sun.COM) for sc22wg5@open-std.org; Mon, 08 Dec 2008 18:49:08 -0800 (PST) Received: from [129.146.84.104] by fe-sfbay-09.sun.com (Sun Java System Messaging Server 6.2-8.04 (built Feb 28 2007)) with ESMTPSA id <0KBL00GRO95VL370@fe-sfbay-09.sun.com>; Mon, 08 Dec 2008 18:49:08 -0800 (PST) Date: Mon, 08 Dec 2008 18:49:07 -0800 From: Robert Corbett Subject: Re: (j3.2006) (SC22WG5.3757) Ballot on the technical content of the TR In-reply-to: <20081208154207.B50ABC178E0@www2.open-std.org> To: fortran standards email list for J3 Cc: WG5 Reply-To: Robert.Corbett@Sun.COM Message-id: <493DDCA3.3050104@sun.com> Organization: Sun Microsystems, Inc. MIME-version: 1.0 Content-type: text/plain; format=flowed; charset=us-ascii Content-transfer-encoding: 7BIT X-Accept-Language: en-us, en References: <20081127193527.EF00DC178D9@www2.open-std.org> <20081208024650.76234C4596C@www2.open-std.org> <20081208154207.B50ABC178E0@www2.open-std.org> User-Agent: Mozilla/5.0 (X11; U; SunOS sun4u; en-US; rv:1.7.13) Gecko/20060509 Sender: owner-sc22wg5@open-std.org Precedence: bulk Craig Rasmussen wrote: > > On Dec 7, 2008, at 7:46 PM, Jim Xia wrote: > >> 2.) Fortran descriptors >> Although Fortran descriptors are used when passing assumed-shape >> arrays, pointer >> arrays and allocatable arrays by many vendors, they are however not >> universally used >> by all vendors. Based on a survey earlier this year (by Craig >> Rasmussen at J3 m183), >> some vendors haven't adopted descriptors for assumed shape arrays, >> pointer arrays >> or allocatable arrays. The requirement in the C-interop TR may pose >> implementation >> difficulties for those vendors. Furthermore allowing updates on >> Fortran descriptors from >> C programs will likely cause safety issues and also be problematic in >> consistency >> check by some vendors. This becomes a sure way to introduce bugs >> difficult to diagnose. > > > I'm not sure what I said about descriptors at J3 m183 but I certainly > didn't intend to give the impression that some vendors don't implement > Fortran descriptors. In fact, EVERY vendor I have been able to test > does. Some vendors don't include the rank as part of the descriptor, > though most do. Perhaps this is what Jim is referring to. > > Regards, > Craig Sun Fortran uses decriptors for assumed-shape arrays, but the descriptors contain only those components required by the Fortran language. The structure used as a descriptor for an assumed-shaped array of rank n has the form: actual origin (an address) extents (n unsigned longs) strides (n signed longs) I am not pleased that the proposal is making other vendors' extensions to the data structures, beyond what is needed for Fortran, part of the Fortran language. Bob Corbett