220 8346 <320a5135-1841-4fae-9dca-e0b3c582db85@isocpp.org> article Path: news.gmane.org!not-for-mail From: fmatthew5876@gmail.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Proposal: Default swap operation Date: Wed, 1 Jan 2014 18:33:13 -0800 (PST) Lines: 151 Approved: news@gmane.org Message-ID: <320a5135-1841-4fae-9dca-e0b3c582db85@isocpp.org> References: <25282740.R0qdXlWiI6@tjmaciei-mobl2> <52C46F6D.7080303@gmail.com> <4890722.aJTBCHXWVh@tjmaciei-mobl2> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_636_28550004.1388629993893" X-Trace: ger.gmane.org 1388629998 3482 80.91.229.3 (2 Jan 2014 02:33:18 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 2 Jan 2014 02:33:18 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDELF54RTIGRB2U7SOLAKGQE5LOTLTY@isocpp.org Thu Jan 02 03:33:24 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oa0-f69.google.com ([209.85.219.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VyY62-0000d1-89 for gclcip-std-proposals@m.gmane.org; Thu, 02 Jan 2014 03:33:18 +0100 Original-Received: by mail-oa0-f69.google.com with SMTP id h16sf69762117oag.8 for ; Wed, 01 Jan 2014 18:33:15 -0800 (PST) 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=80hQKRf6APDjmKgutylS1GczYayoRVv4+XyiIa64Uh0=; b=Ct9TvKEkBG4hJwnqr1hoxAQ5N4U2Nr3wNurgq1gwS0IgEjwd/qYKHqznhFR+rHEvsH LEdXiwGTdQNfjhyLhjEqkUplRhcO3RUBuzQTJl8yTPH3krYVI5H9JpCc+0St9rPInLjN tEY6xGnhMQpbhGZliWAvrALkY6dslTeBhUj7dL9WRVPyWU941HqyDC6tN8aLJxRjhH9Q MKbh8TFs1MHFLVLlkJqZa1GOaimKzkmX7f5NU7YvCDsPLnUq1ucdA+ta4Kxi1A4Mz0Jf L92S+QmkYVyqVm5zrcDtzKbJ2+rbZt7o9J0wAFEBBwQo0uXHc22SAfydNx9/kKLL8Gyh 24ug== 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=80hQKRf6APDjmKgutylS1GczYayoRVv4+XyiIa64Uh0=; b=E1jFk1NLzdS7vHV658YtLtJoYRdtoAYMsQBvCme0sNdlgSn1WGSsbzmz5hPcdefOEk yVU2SrLblmvipUnoZSTggDGfqK0LUfZOzTZ0kH+7M8GU/WXDHg42y2AJ0JTjjgXoxjpr Ii1T/+CLnTtGoYw7iL6AKv7SC3pGFTlHEKjRfPYTZAe3i2AmjgEsBxptkIxluffwNGsx hlcN/H509hR/gajcoXtuw6cZXrOYMHoSwhxSEkI3tYEGg+vPE26jvgFWEHYKU0Q/uKO4 Kx8S9gxDT8CwPMXe5O7uNQDP94EsTn8Ju6YFWBbZaLILCqYiDz65OdEAvJbFb1/1EtNE FvTg== X-Gm-Message-State: ALoCoQlXmO+GfAvzQtphQxpPkO6Lb8j+PeHZzDXe2+NMflt+h3yhL+Z+SDs2Sp88y72r11CSOwfy X-Received: by 10.43.161.202 with SMTP id mh10mr8688804icc.23.1388629995012; Wed, 01 Jan 2014 18:33:15 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.49.4.138 with SMTP id k10ls4195048qek.13.gmail; Wed, 01 Jan 2014 18:33:14 -0800 (PST) X-Received: by 10.49.35.11 with SMTP id d11mr628qej.8.1388629994476; Wed, 01 Jan 2014 18:33:14 -0800 (PST) In-Reply-To: X-Original-Sender: fmatthew5876@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:8346 Archived-At: ------=_Part_636_28550004.1388629993893 Content-Type: text/plain; charset=ISO-8859-1 On Wednesday, January 1, 2014 8:23:01 PM UTC-5, Howard Hinnant wrote: > > On Jan 1, 2014, at 8:00 PM, Thiago Macieira > > wrote: > > > On quarta-feira, 1 de janeiro de 2014 14:41:33, Matthew Woehlke wrote: > >>> And quite frankly I don't see the benefit. This destructor can't be > from > >>> other translation units under the conditions you described. > >> > >> Yes. This would need to be changed for the idea to be useful. So there > >> is still something that could be changed here; specifying that '= > >> default' should make the definition accessible to other translation > >> units the same as if a user definition had been provided. (If it is not > >> possible to change the behavior of '= default', then I would propose '= > >> extern default' instead to explicitly specify that a symbol should be > >> emitted.) > > > > This part of the discussion was probably wrong on my part. > > > >>> This destructor cannot be trivial either under your condition: if all > of > >>> them were trivial, then you could have left the declaration in the > >>> header. > >> Right. If '= default' appears in the .cpp and not in the .h, the > >> compiler shall (be free to) assume that it is non-trivial. Because in > >> practice, if you need it in the .cpp and not the .h it is likely > >> (always?) because it is non-trivial anyway. > > > > But this one is still right. This may be allowed, but I don't see the > point in > > doing it this way, since the code produced will be exactly the same. > > > > You may disagree with me here, but whenever two syntaxes produce the > exactly > > same thing with no overhead and no difference in readability, I'd choose > the > > older syntax. > > Is it me, or does the subject of this thread seem completely unrelated to > the subject line in the mail (for the vast majority of posts in this > thread)? > > It has. Everyone, can we get back on topic with the idea of a defaulted swap operator? > Howard > > -- --- 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_636_28550004.1388629993893 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable


On Wednesday, January 1, 2014 8:23:01 PM UTC-5, Ho= ward Hinnant wrote:
On Jan 1, 2= 014, at 8:00 PM, Thiago Macieira <t= hi...@macieira.org> wrote:

> On quarta-feira, 1 de janeiro de 2014 14:41:33, Matthew Woehlke wr= ote:
>>> And quite frankly I don't see the benefit. This destructor= can't be from
>>> other translation units under the conditions you described= ..
>>=20
>> Yes. This would need to be changed for the idea to be useful. = So there
>> is still something that could be changed here; specifying that= '=3D
>> default' should make the definition accessible to other transl= ation
>> units the same as if a user definition had been provided. (If = it is not
>> possible to change the behavior of '=3D default', then I would= propose '=3D
>> extern default' instead to explicitly specify that a symbol sh= ould be
>> emitted.)
>=20
> This part of the discussion was probably wrong on my part.
>=20
>>> This destructor cannot be trivial either under your condit= ion: if all of
>>> them were trivial, then you could have left the declaratio= n in the
>>> header.
>> Right. If '=3D default' appears in the .cpp and not in the .h,= the
>> compiler shall (be free to) assume that it is non-trivial. Bec= ause in
>> practice, if you need it in the .cpp and not the .h it is like= ly
>> (always?) because it is non-trivial anyway.
>=20
> But this one is still right. This may be allowed, but I don't see = the point in=20
> doing it this way, since the code produced will be exactly the sam= e.
>=20
> You may disagree with me here, but whenever two syntaxes produce t= he exactly=20
> same thing with no overhead and no difference in readability, I'd = choose the=20
> older syntax.

Is it me, or does the subject of this thread seem completely unrelated = to the subject line in the mail (for the vast majority of posts in this thr= ead)?


It has. Everyone, can we get back on t= opic with the idea of a defaulted swap operator?
 
Howard

--
 
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