From -3522381644747761859 X-Google-Thread: 7894ca11fe,2030f7dfcae4edfc X-Google-Attributes: gid7894ca11fe,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Received: by 10.180.73.173 with SMTP id m13mr3121527wiv.4.1350352564457; Mon, 15 Oct 2012 18:56:04 -0700 (PDT) MIME-Version: 1.0 Path: q11ni134324890wiw.1!nntp.google.com!feeder1.cambriumusenet.nl!94.232.116.12.MISMATCH!feed.xsnews.nl!border-2.ams.xsnews.nl!xlned.com!feeder3.xlned.com!feeder3.cambriumusenet.nl!feed.tweaknews.nl!216.196.110.142.MISMATCH!border3.nntp.ams.giganews.com!border1.nntp.ams.giganews.com!nntp.giganews.com!news.panservice.it!feeder.erje.net!news.albasani.net!.POSTED!not-for-mail From: =3D?ISO-8859-1?Q?Daniel_Kr=3DFCgler?=3D Newsgroups: comp.std.c++ Subject: Re: What's a "side effect" Date: Mon, 8 Oct 2012 09:11:55 -0700 (PDT) Organization: A noiseless patient Spider Lines: 42 Sender: std-cpp-request@vandevoorde.com Approved: austern@google.com Message-ID: References: <506de288$0$71204$742ec2ed@news.sonic.net> NNTP-Posting-Host: 8WGHjMh66F+vQugWNNV1JlweYf3UwFXFIRbYE5Yng+w= X-Trace: news.albasani.net lnqIy0oH6aZCdo+TWT97M68EI55vX9lG3n+oOq4kyno6iw0gMAN+7EI4Hr81REqhdcdcef2KXeUWQPdk+udu8g== X-Complaints-To: abuse@albasani.net NNTP-Posting-Date: Mon, 8 Oct 2012 16:11:59 +0000 (UTC) X-Mailer: Perl5 Mail::Internet v2.05 X-Submission-Address: std-cpp-submit@vandevoorde.com Cancel-Lock: sha1:INR+x5kdHr0o8h/Ty4n8RZsygHc= X-Original-Date: Mon, 08 Oct 2012 07:27:01 +0200 Bytes: 2962 Content-Type: text/plain; charset=ISO-8859-1; format=flowed [2nd attempt after three days] On 2012-10-05 10:35, Andy Lutomirski wrote: > > I'm trying to userstand the memory model. [intro.multithread] mentions > lots of things like: > > A release sequence ... is a maximal contiguous sub-sequence of side effects > > I know what a /visible/ side effect is (see #13), but that doesn't tell > me what a side effect is in the first place. I assume that a "side > effect" is just a write (e.g. "a = b" has a side effect of modifying a= ), > but AFAICS the N3376 has no language to support that assumption. I think that the current wording defines what a /side effect/ is. This is specified in [intro.execution] p12: "Accessing an object designated by a volatile glvalue (3.10), modifying an object, calling a library I/O function, or calling a function that does any of those operations are all /side effects/, which are changes in the state of the execution environment. Evaluation of an expression (or a sub-expression) in general includes both value computations (including determining the identity of an object for glvalue evaluation and fetching a value previously assigned to an object for prvalue evaluation) and initiation of side effects. When a call to a library I/O function returns or an access to a volatile object is evaluated the side effect is considered complete, even though some external actions implied by the call (such as the I/O itself) or by the volatile access may not have completed yet." HTH & Greetings from Bremen, Daniel Kr=FCgler -- [ comp.std.c++ is moderated. To submit articles, try posting with your ] [ newsreader. If that fails, use mailto:std-cpp-submit@vandevoorde.com ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ]