220 13020 article Path: news.gmane.org!not-for-mail From: Vittorio Romeo Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Compile-time static `std::integral_counter` Date: Fri, 19 Sep 2014 10:40:55 -0700 (PDT) Lines: 111 Approved: news@gmane.org Message-ID: References: <9a0bde7b-2f0a-4a5b-92a4-88d5e8df7ea9@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_2799_368633182.1411148455858" X-Trace: ger.gmane.org 1411148466 13930 80.91.229.3 (19 Sep 2014 17:41:06 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 19 Sep 2014 17:41:06 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCO3NDEYZQHRBKOV6GQAKGQEDT67DRI@isocpp.org Fri Sep 19 19:41:00 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oi0-f69.google.com ([209.85.218.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XV2B0-0004zh-Pq for gclcip-std-proposals@m.gmane.org; Fri, 19 Sep 2014 19:40:59 +0200 Original-Received: by mail-oi0-f69.google.com with SMTP id u20sf14383310oif.0 for ; Fri, 19 Sep 2014 10:40:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=IQV5l1HjG09e4pHFiHdGASlCo/GeebAGCSKu1747q9Q=; b=QHzO3zwsiMSs3NCWLk2Io/ml9tTYg/HFP6IL2uAObFjLBfVL8rtOamA2HUl24uytcS sxMNh3C0v14VAub5cCBYTot4AC1wsa7g/cEWMnBK43YQYGUGihB57a+X2wl25L6Pj3hM GH9V6h4Pom8fUQZzwXFvqlDmV7t7B0YuoBDcjP9ezRTVYcBdA7evH7agNOrDm/86WzJx es7YWddarsmhnFV49HVwNbdwkPWS1k8NUrIt0d0dTnsDJx1IjVGkmKf4F+J9vIFd1JGH nlFHeF/S2GTQZehyPoTedV9va3tJBdjhXbVN6rs+HJ/CNwo3skc2VbYkHJASFrBkCd1f QvJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:x-original-sender:reply-to:precedence :mailing-list:list-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=IQV5l1HjG09e4pHFiHdGASlCo/GeebAGCSKu1747q9Q=; b=DQ+uMpk4Cr1cXqh00Y9QZTeeL1Pk8RYzVoTO0HVDkND1aXe4yiyhDIsAfeRXvdBsZ4 +gAudEL6KNaIzFL1zKMfEE+HlGziUfCc2/BDyOqVFy924JD/34JfB474y+ELVlyjcxtg BH/WMF3pYJ5uRwrG1lN84ExFF64jqIdesL+9kQ+fpqUFnrWNJK7/wXro5rvEW0E+aRqJ KGopHwmBSmYha85eBEA+6B3ZLln+jGA3HgVT4ZTkM1gmQxfHxyJatL8BzYciyuuwKU6y C0KGRBllrArgQWZOKp2G6l0krV0hGKmQqSor3lFqze4A7uomYk4pcqwowcvSrDtbh9sh ZcFA== X-Gm-Message-State: ALoCoQnC4MrwpCT08wCVvWQBcZHyJfRbHKBW/ul6vlgbff+z064c4nFr0ISysLlaHEHQGzPJ88HY X-Received: by 10.182.22.201 with SMTP id g9mr2099354obf.18.1411148457717; Fri, 19 Sep 2014 10:40:57 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.101.207 with SMTP id u73ls818847qge.34.gmail; Fri, 19 Sep 2014 10:40:56 -0700 (PDT) X-Received: by 10.140.30.246 with SMTP id d109mr47805qgd.7.1411148456967; Fri, 19 Sep 2014 10:40:56 -0700 (PDT) In-Reply-To: X-Original-Sender: vittorio.romeo.vee@gmail.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:13020 Archived-At: ------=_Part_2799_368633182.1411148455858 Content-Type: text/plain; charset=UTF-8 On Friday, 19 September 2014 19:13:48 UTC+2, inkwizyt...@gmail.com wrote: > > Why don't move this types to one typedef? > typedef any_variadic_template typeColection; > template > constexpr int f() { return type_pos_in_param::value; } > > You can query this type anywhere you want. > This requires creating and maintaining a list of types... which it's (should be) unnecessary and it's very cumbersome for the user of my libraries. --- On Friday, 19 September 2014 19:23:22 UTC+2, David Krauss wrote: > > I see some discussion of the ODR in this thread. Any counter usage with > linkage does need to be placed in the header file and repeated exactly the > same in each TU. Avoid sharing a counter between headers unless those > headers are all-or-nothing. > Can you elaborate more on this? What I am currently doing is putting the workaround code in an header file (header-only library) and using inline in every function. Is that not guaranteed to return expected values in different TUs? (values that never repeat, I mean) -- --- 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/. ------=_Part_2799_368633182.1411148455858 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Friday, 19 September 2014 19:13:48 UTC= +2, inkwizyt...@gmail.com wrote:
Why don't move this types to one typedef?
typedef any_variadic_template<A,=  B, C, D> typeColection;
template<= ;typename T>
constexpr int f() { return type_pos_in_param<T, typeColection>::value; <= span style=3D"color: rgb(102, 102, 0);">}

You can query= this type anywhere you want.

= This requires creating and maintaining a list of types... which it's (shoul= d be) unnecessary and it's very cumbersome for the user of my libraries.

---

On Friday, 19 Septembe= r 2014 19:23:22 UTC+2, David Krauss wrote:
I see some discussion of the ODR in this thread. Any counter usage = with linkage does need to be placed in the header file and repeated exactly= the same in each TU. Avoid sharing a counter between headers unless those = headers are all-or-nothing.

<= /div>
Can you elaborate more on this? What I am currently doing is putt= ing the workaround code in an header file (header-only library) and using i= nline in every function. Is that not guaranteed to return expected values i= n different TUs? (values that never repeat, I mean)

--

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