220 4736 article Path: news.gmane.org!not-for-mail From: Lawrence Crowl Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: lock free traits for functions Date: Wed, 29 May 2013 15:18:48 -0700 Lines: 97 Approved: news@gmane.org Message-ID: References: <4ed4041c-a458-4fc8-ae3d-7534d5d261c2@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 X-Trace: ger.gmane.org 1369865931 5293 80.91.229.3 (29 May 2013 22:18:51 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 29 May 2013 22:18:51 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCY3D77DYUDBBSX5TGGQKGQEL2H5PAA@isocpp.org Thu May 30 00:18:53 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qa0-f72.google.com ([209.85.216.72]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Uhohn-0005mk-IG for gclcip-std-proposals@m.gmane.org; Thu, 30 May 2013 00:18:51 +0200 Original-Received: by mail-qa0-f72.google.com with SMTP id bs12sf5921526qab.3 for ; Wed, 29 May 2013 15:18:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlers.com; s=googlers; h=x-beenthere:mime-version:in-reply-to:references:date:message-id :subject:from:to:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:x-google-group-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=6nTtvdd9osOuRLdU7WHHGFMmg9MPYf0Wwskqc7S8C1o=; b=DMp3xgNmXe/k7WOwVrwW1C904a3aNQh6htWZDNrw6IS9dDgqJqQWe6+HSRhc0FntHo YoXw7Ri97cHlLTJG43IEfLwLFN5UjT4xChmJzCERYN2SYYmDFyar1H83gPjE2yvi+hYc T4DiXtOjbsuiw5QGeEplqRvPrs0UyNFpdG7pU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-beenthere:mime-version:in-reply-to:references:date:message-id :subject:from:to:x-gm-message-state:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-google-group-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=6nTtvdd9osOuRLdU7WHHGFMmg9MPYf0Wwskqc7S8C1o=; b=nC1Klgdy/WSmrs/To1zezlsJI92CcZ9f19oovuTT3VAfAMwhimFiYlfq8f6HeU5Yzr MKU3NFWgBYScTqGoIUZBSOYJ6sQgRFgpt0Rp/hKK/chWmWAfZsrm+YhGwdmMU6sqaBRB 6Jcfd2FA21znDzel1kH3Viu6kcNBaeK2RmZ8+9WhF4nOHjb69EcxWNK8gTcfVl9yUp+g xHXd2MSGkOoGLRNK2yZhy514S9lKw8fnJgA9Y3EQuVfKGtS6VxAstWrJ5GQAJdlTIh9g z560ZDhYSzd2lIGkzUWt6Hu6fM1P/jDL3cXH9EyDwHIIqG5+B93j4MaerKKtB4UxHEhK Ulfg== X-Received: by 10.224.53.198 with SMTP id n6mr2679748qag.2.1369865930627; Wed, 29 May 2013 15:18:50 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.49.5.8 with SMTP id o8ls115932qeo.24.gmail; Wed, 29 May 2013 15:18:49 -0700 (PDT) X-Received: by 10.49.28.35 with SMTP id y3mr5321130qeg.7.1369865929595; Wed, 29 May 2013 15:18:49 -0700 (PDT) Original-Received: from mail-qc0-x231.google.com (mail-qc0-x231.google.com [2607:f8b0:400d:c01::231]) by mx.google.com with ESMTPS id e17si13740432qct.127.2013.05.29.15.18.48 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 29 May 2013 15:18:48 -0700 (PDT) Received-SPF: pass (google.com: domain of crowl@google.com designates 2607:f8b0:400d:c01::231 as permitted sender) client-ip=2607:f8b0:400d:c01::231; Original-Received: by mail-qc0-f177.google.com with SMTP id e1so4989778qcy.8 for ; Wed, 29 May 2013 15:18:48 -0700 (PDT) X-Received: by 10.49.34.130 with SMTP id z2mr5291595qei.25.1369865928315; Wed, 29 May 2013 15:18:48 -0700 (PDT) Original-Received: by 10.229.1.196 with HTTP; Wed, 29 May 2013 15:18:48 -0700 (PDT) In-Reply-To: X-Gm-Message-State: ALoCoQkXg1s5rcFRQOAyYTKeVUFuMqyNqcTDSWu9LL57bcw0zlarMxkJOWHB2uUo4/HbtjF/rbkT3tI7g0x5TaDWEek0AzHx10rnp6DjjfrD6iy1ilTRRpH9U1Li84nMtTm4ochB5+ny1kz180wfCVV6mtS9sxT+vvbSGp9wa9UyoZbMt44aaFh2brpe4//DPT93hhHeVHje X-Original-Sender: crowl@googlers.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of crowl@google.com designates 2607:f8b0:400d:c01::231 as permitted sender) smtp.mail=crowl@google.com; dkim=pass header.i=@googlers.com; dmarc=pass (p=QUARANTINE dis=none) d=googlers.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:4736 Archived-At: On 5/29/13, adrien courdavault wrote: > Clearly a static info would be great if possible, that is why i said a > trait > I don't have a clear list in mind, but any "status" function like > future::valid I would like to have this feature > also, It could be interesting on some containers in general or > allocators (like allocators). But this could also be done by choosing > policies (the problem could then be that some policies are not > implemented). I looked at the lockfree lib of boost recently, it is > nice but not so clear to use. > > In general that could be useful for anything which depending on the > implementation should or may be lock free or not. > Also then comes the issue of lock free vs wait free ... > > I don't know really what is best but I really miss a feature that > could be used to say this is ok, this is not. > > Finally the problem with compile time would be for dlls.. maybe having > a way to get this compile time info at runtime would be nice, so it > would work with dll/so too. > > I know this is not really clear It would be helpful if you could write a paper, presenting your examples and including a list of functions for which you really need the answer. > > On 29 May 2013 21:24, Lawrence Crowl wrote: >> On 5/29/13, adrien courdavault wrote: >>> This seams to be a very simplistic request but I think it would be >>> nice to have some traits to know if a function call is lock free >>> or not. It is not usefull for every function, but it could be >>> for the class like thread obviously. Clearly launching a thread >>> is not, but depending on the implementation get_id could be; >>> >>> I say that because in time critical thread you want to know it >>> it is safe to do that. In my case i want to know if I am in the >>> time critical thread, ... problem, if asking for the id of the >>> thread is not lock free I might just have break the rule I wanted >>> to inforce by asking if I was in this thread, what do you think? >> >> We might be able to provide this query definitively for a >> pre-determined set of functions. In general, though, I think we >> would need to be able to answer "don't know". >> >> Do you have a list of other functions for which you must know? >> Do you need a dynamic test, i.e. on a function pointer, or can >> you live with a static test, i.e. on a template argument? >> >> -- >> Lawrence Crowl >> >> -- >> >> --- >> You received this message because you are subscribed to a topic in the >> Google Groups "ISO C++ Standard - Future Proposals" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/a/isocpp.org/d/topic/std-proposals/2iCzaKc2PRE/unsubscribe?hl=en. >> To unsubscribe from this group and all its topics, send an email to >> std-proposals+unsubscribe@isocpp.org. >> To post to this group, send email to std-proposals@isocpp.org. >> Visit this group at >> http://groups.google.com/a/isocpp.org/group/std-proposals/?hl=en. >> >> > > -- > > --- > You received this message because you are subscribed to the Google Groups > "ISO C++ Standard - Future Proposals" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to std-proposals+unsubscribe@isocpp.org. > To post to this group, send email to std-proposals@isocpp.org. > Visit this group at > http://groups.google.com/a/isocpp.org/group/std-proposals/?hl=en. > > > -- Lawrence Crowl -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/?hl=en. .