From owner-sc22wg5@open-std.org Sat Jul 26 00:38:28 2008 Return-Path: X-Original-To: sc22wg5-dom6 Delivered-To: sc22wg5-dom6@open-std.org Received: by open-std.org (Postfix, from userid 521) id 2DED1DE4B9; Sat, 26 Jul 2008 00:38:28 +0200 (CET DST) X-Original-To: sc22wg5@open-std.org Delivered-To: sc22wg5@open-std.org Received: from mail1.cray.com (mail1.cray.com [136.162.0.111]) by open-std.org (Postfix) with ESMTP id 80BCB60EE7 for ; Sat, 26 Jul 2008 00:38:14 +0200 (CET DST) 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 m6PMbj2s012752 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 25 Jul 2008 17:37:46 -0500 (CDT) Received: from CFEXFE01.us.cray.com (cfexfe01.us.cray.com [172.30.74.93]) by beaver.us.cray.com (8.13.8/8.13.3/hub-5273) with ESMTP id m6PMbix8030321; Fri, 25 Jul 2008 17:37:44 -0500 Received: from mh-dhcp-172-31-20-57.us.cray.com ([172.31.20.57]) by CFEXFE01.us.cray.com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.3959); Fri, 25 Jul 2008 17:37:44 -0500 Message-ID: <488A55C0.5000906@cray.com> Date: Fri, 25 Jul 2008 17:37:52 -0500 From: Bill Long Reply-To: longb@cray.com Organization: Cray Inc. User-Agent: Thunderbird 2.0.0.9 (Macintosh/20071031) MIME-Version: 1.0 To: Jim Xia CC: sc22wg5 Subject: Re: (j3.2006) (SC22WG5.3591) Assumed-type and Assumed-rank extensions for C Interop TR. References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 25 Jul 2008 22:37:44.0508 (UTC) FILETIME=[0E30AFC0:01C8EEA7] X-Cray-VirusStatus: clean Sender: owner-sc22wg5@open-std.org Precedence: bulk Jim Xia wrote: > > Bill Long wrote on 07/25/2008 02:38:50 PM: > > > > The basic problem is Fortran side can not use this type directly. If > > > the procedure is defined in Fortran for C, then how can a Fortran > > > programmer "map" this dummy argument to real Fortran data type. > > > > In what way does C_F_POINTER fail to solve this problem? It was > > explicitly designed to be used on the Fortran side to give a Fortran > > type, type parameters, and shape to a block of memory pointed to by a C > > address. > > > > Read what's written in C_F_POINTER on page 394 > > > (1) If the value of CPTR is the C address of an interoperable data > entity, FPTR shall be a data pointer with type and type parameters > interoperable with the type of the entity. In this case, FPTR > becomes pointer associated with the target of CPTR. If FPTR is > an array, its shape is specified by SHAPE and each lower bound > Option 1 is the one we want to apply. If the wording of the draft is such that these conditions are not met, then fixes are needed. > > > In any case, it is asking for the pointer association. I don't see > how TYPE(*) can fit in here yet. > The FPTR argument was declared integer,pointer,dimension(:), so it is clearly a pointer. The effect of executing c_f_pointer is to cause that pointer to be associated with the target of CPTR, which in this case is the buffer that was declared type(*). C_F_POINTER does not ask for pointer association, it causes pointer association. Cheers, Bill > > Cheers, > > Jim Xia > > RL Fortran Compiler Test > IBM Toronto Lab at 8200 Warden Ave, Markham, On, L6G 1C7 > Phone (905) 413-3444 Tie-line 313-3444 > email: jimxia@ca.ibm.com > D2/YF7/8200 /MKM -- Bill Long longb@cray.com Fortran Technical Support & voice: 651-605-9024 Bioinformatics Software Development fax: 651-605-9142 Cray Inc., 1340 Mendota Heights Rd., Mendota Heights, MN, 55120