From owner-sc22wg5@open-std.org Mon Dec 6 14:41:48 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 60428C3BA1C; Mon, 6 Dec 2010 14:41:48 +0100 (CET) X-Original-To: sc22wg5@open-std.org Delivered-To: sc22wg5@open-std.org Received: from smtp.cims.nyu.edu (SMTP.CIMS.NYU.EDU [128.122.49.100]) by www2.open-std.org (Postfix) with ESMTP id BFEF7C178E4 for ; Mon, 6 Dec 2010 14:41:46 +0100 (CET) Received: from [192.168.1.2] (pool-108-27-16-195.nycmny.fios.verizon.net [108.27.16.195]) (authenticated bits=0) by smtp.cims.nyu.edu (8.14.3/8.13.8) with ESMTP id oB6Dfimt008455 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 6 Dec 2010 08:41:45 -0500 (EST) Message-ID: <4CFCE81A.8090408@courant.nyu.edu> Date: Mon, 06 Dec 2010 08:41:46 -0500 From: Aleksandar Donev User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.12) Gecko/20101027 Thunderbird/3.1.6 MIME-Version: 1.0 To: SC22WG5 Subject: Re: (j3.2006) (SC22WG5.4368) [ukfortran] WG5 informal ballot re Interop. TR References: <20101108175805.5B97EC178E5@www2.open-std.org> <20101206103130.1AE8AC178E3@www2.open-std.org> In-Reply-To: <20101206103130.1AE8AC178E3@www2.open-std.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-sc22wg5@open-std.org Precedence: bulk On 12/6/2010 5:31 AM, Malcolm Cohen wrote: > Inclusion of the type field in the descriptor > should probably be reconsidered. I in principle agree but I also deel that going around in circles and never converging should be avoided. > A reasonable alternative would be to > forbid passing TYPE(*) actuals to TYPE(*) dummies. This is too drastic. We want to disallow TYPE(*) assumed-shape or explicit-shape dummies (that is, ones that do not carry a descriptor) to be passed as actuals for TYPE(*) dummies. That way, we ensure that type information is always present. One can still write wrappers in Fortran that have TYPE(*) dummies, but they will always be assumed rank. C routines on the other hand can avoid descriptors, but can also rely on having type information. Does this seem acceptable? > If we go for the "forbid" route, I hope > that we can pass CLASS(*) actuals to TYPE(*) dummies - and that if this > ends up in a C descriptor that the descriptor fields "type" (if we keep > that) and "elem_size" (and "length" if we get that) are set > appropriately. In fact I think we can do that anyway as the TR stands. Yes, CLASS(*) or in fact any polymorphic thingo that already carries a hidden type descriptor could be allowed as an actual argument corresponding to a TYPE(*) dummy. But we need to decide this and put it in writing in the TR. Best, Aleks -- Aleksandar Donev, Assistant Professor of Mathematics Courant Institute of Mathematical Sciences Office: 909 Warren Weaver Hall, New York University E-mail: donev@courant.nyu.edu Phone: (212) 992-7315; Fax: (212) 995-4121 Mailing address: 251 Mercer St, New York, NY 10012 Web: http://cims.nyu.edu/~donev