From owner-sc22wg5@open-std.org Tue Nov 11 09:33:58 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 44A1CC178DC; Tue, 11 Nov 2008 09:33:58 +0100 (CET) X-Original-To: sc22wg5@open-std.org Delivered-To: sc22wg5@open-std.org Received: from ns.nag-j.co.jp (218-42-159-107.cust.bit-drive.ne.jp [218.42.159.107]) by www2.open-std.org (Postfix) with ESMTP id 2185BC178D9 for ; Tue, 11 Nov 2008 09:33:55 +0100 (CET) Received: from 218-42-159-108.cust.bit-drive.ne.jp ([218.42.159.108] helo=[127.0.0.1]) by ns.nag-j.co.jp with esmtp (Exim 4.50) id 1Kzogy-0005CP-9c for sc22wg5@open-std.org; Tue, 11 Nov 2008 17:33:44 +0900 Message-ID: <491943B1.2070904@nag-j.co.jp> Date: Tue, 11 Nov 2008 17:34:57 +0900 From: Malcolm Cohen User-Agent: Thunderbird 3.0a1pre (Windows/2008022014) MIME-Version: 1.0 To: WG5 Subject: Re: (j3.2006) (SC22WG5.3653) [ukfortran] FW: Notes on WG5 coarray papers References: <49137AD3.1070402@lrz.de> <20081110124449.AEBF1C178E0@www2.open-std.org> <20081111030258.C9550C178D9@www2.open-std.org> <49193B79.8030807@lrz.de> In-Reply-To: <49193B79.8030807@lrz.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-sc22wg5@open-std.org Precedence: bulk Hi folks, Reinhold Bader wrote: > > [discussion on restriction I want but cannot get] > > Do you think this is then only a matter of telling users > "don't use volatile (array, derived type) coarrays thusly" or > something which needs fixing in the standard in a more > appropriate manner than suggested by me? > Probably more the latter than the former. I usually prefer to have less ambiguity in my standards. >>> Example 2.4 ("Protected Context") is non-conforming since the cited >>> restriction is violated by the object in question being VOLATILE within >>> the scope of the DO loop. This would apply even if the CASE(1) statements >>> were not present. >>> >>> >> There is no restriction that says a DO index variable cannot have the >> VOLATILE attribute, and the "cited restriction" does not even mention >> VOLATILE. So I cannot agree with your reasoning. (In fact I think the >> example is conforming when used as described in the paper.) >> > > I don't agree with that one. Referring to 08-007r2, we have > > 5.3.19 para1: The VOLATILE attribute specifies that an object may be referenced, > defined, or become undefined, by means not specified by the program, > or by another image without synchronization. > > so if the DO index variable is volatile, it will by virtue of its volatility violate the cited > restriction, won't it? No. It only violates the restriction if it actually *IS* defined etc. This is not a static restriction but a dynamic one. > Or do you consider the program conforming (statistically > conforming?) as long as simply by chance the index isn't stomped on by anyone > else while DO executes? > That is *EXACTLY* what those words mean. Like in the Fortran 90 program snippet INTEGER x(100) EQUIVALENCE(x(50),i) x = 0 DO i=1,10 READ *,j x(j) = i END DO That is not conforming if the user types in a number <1 or >100 (subscript error) or ==50 (updating a DO index error); it is conforming otherwise. Cheers, -- .........................Malcolm Cohen, Nihon NAG, Tokyo.