220 18771 article Path: news.gmane.org!not-for-mail From: David Krauss Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: First draft: Non-copyable call wrapper, std::unique_function Date: Thu, 25 Jun 2015 15:51:01 +0800 Lines: 84 Approved: news@gmane.org Message-ID: References: <59ED9069-2650-44E2-B00E-0E56ED37B83D@gmail.com> <4f0124c9-aa8e-4d40-b10e-7b3bee362398@isocpp.org> <5dcf242c-aef0-4d0b-b2f7-45273968cba9@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) Content-Type: multipart/alternative; boundary="Apple-Mail=_A998E045-A328-4515-9406-1FE7D7FE2831" X-Trace: ger.gmane.org 1435218679 4401 80.91.229.3 (25 Jun 2015 07:51:19 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 25 Jun 2015 07:51:19 +0000 (UTC) Cc: std-proposals@isocpp.org To: Arthur O'Dwyer Original-X-From: std-proposals+bncBCW25A7E3QCRB2PFV2WAKGQE4FZQV5A@isocpp.org Thu Jun 25 09:51:10 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ig0-f197.google.com ([209.85.213.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Z81wB-0005Nd-86 for gclcip-std-proposals@m.gmane.org; Thu, 25 Jun 2015 09:51:07 +0200 Original-Received: by igbqq3 with SMTP id qq3sf118196429igb.2 for ; Thu, 25 Jun 2015 00:51:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:content-type:mime-version:subject:from :in-reply-to:date:cc:message-id:references:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=1qBTb8cgT8UTvBDs6OHMRSNq1P7bLXvrhanVkNFYFZs=; b=QIITia9/WyMlVkUEfmh1uVbfE3I2JAQkrvmrFRWc7hkeHU6naIuE9Iq5prbZw6Ci1D 4gIeEjNfahJg1L37gRRdtOglN1h710PgRv+d6mROBaFAeH6qWDHNMv9SK0t4/v9P2g5j kvya0PsKK3kUm464+zWKJn2BxYfvXGBImiRW8mouvanMz024k2duqIiEtxSkz4r076iB cpm8aA0bOvT3eigRkbI10kr1Cdu953CH3ihh09kHp9KUFa9MBTA913GiCwnTiIUIMngp ZcWYuPS9lNS36HlXRjwwQzRcX1M3WXTjvtKt/x5a1yKre7qsRmefgjIVO3imSExgEtt8 JWTw== X-Gm-Message-State: ALoCoQloXN+qC9qENQ18438h+si/kR57A3PaUw04MdnXB78VisfnG47QlDzM07PKqkMQTFA9u6DD X-Received: by 10.182.213.166 with SMTP id nt6mr62337456obc.3.1435218666055; Thu, 25 Jun 2015 00:51:06 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.169.168 with SMTP id f40ls793854ioj.37.gmail; Thu, 25 Jun 2015 00:51:05 -0700 (PDT) X-Received: by 10.70.38.170 with SMTP id h10mr87373108pdk.20.1435218665430; Thu, 25 Jun 2015 00:51:05 -0700 (PDT) Original-Received: from nk11p04mm-asmtp002.mac.com (nk11p04mm-asmtp002.mac.com. [17.158.236.237]) by mx.google.com with ESMTPS id qp11si43815624pdb.211.2015.06.25.00.51.05 for (version=TLSv1.2 cipher=AES128-GCM-SHA256 bits=128/128); Thu, 25 Jun 2015 00:51:05 -0700 (PDT) Received-SPF: pass (google.com: domain of david_work@me.com designates 17.158.236.237 as permitted sender) client-ip=17.158.236.237; Original-Received: from [172.20.10.2] (unknown [121.54.44.90]) by nk11p04mm-asmtp002.mac.com (Oracle Communications Messaging Server 7.0.5.35.0 64bit (built Mar 31 2015)) with ESMTPSA id <0NQH00LDPPT14800@nk11p04mm-asmtp002.mac.com> for std-proposals@isocpp.org; Thu, 25 Jun 2015 07:51:05 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.14.151,1.0.33,0.0.0000 definitions=2015-06-25_03:2015-06-23,2015-06-25,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1412110000 definitions=main-1506250135 In-reply-to: <5dcf242c-aef0-4d0b-b2f7-45273968cba9@isocpp.org> X-Mailer: Apple Mail (2.2098) X-Original-Sender: david_work@me.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of david_work@me.com designates 17.158.236.237 as permitted sender) smtp.mail=david_work@me.com; dmarc=pass (p=NONE dis=NONE) header.from=me.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:18771 Archived-At: --Apple-Mail=_A998E045-A328-4515-9406-1FE7D7FE2831 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 > On 2015=E2=80=9306=E2=80=9325, at 3:03 PM, Arthur O'Dwyer wrote: >=20 > David Krauss, as the author of N4543 (std::unique_function), do = you think it's in any way preferable to N4159 (std::function), a= s in, I see the confusion now. These are orthogonal problems: 1. Can no more than one copy of the target exist? (Solution: unique_functio= n.)=20 2. Can a given copy be called not more than once? (Solution: function.) N4159 already explains this distinction, but the exposition might not be cl= ear enough. More depth is provided by the link at the end of the previous message. Most= of the time, rvalue ref-qualification is going to be a bit obscure (as it = always has been), and unique_function is what you=E2=80=99ll be looking for= .. --=20 ---=20 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 e= mail 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-proposa= ls/. --Apple-Mail=_A998E045-A328-4515-9406-1FE7D7FE2831 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=UTF-8
On 2015=E2=80=9306= =E2=80=9325, at 3:03 PM, Arthur O'Dwyer <arthur.j.odwyer@gmail.com> wrote:

David K= rauss, as the author of N4543 (std::unique_function<R(A...)>), do you think it's in any= way preferable to N4159 (std::function<R(A...)&&>), as in,

I see the confusion no= w. These are orthogonal problems:

1. Ca= n no more than one copy of the target exist? (Solution: unique_function.) 
2. Can a given copy= be called not more than once? (Solution: function<R(A...)&&>.)

=
N4159 already explains this distinction, but the exposition might not = be clear enough.

More depth is provided= by the link at the end of the previous message. Most of the time, rvalue r= ef-qualification is going to be a bit obscure (as it always has been), and = unique_function is what you=E2=80= =99ll be looking for.

--

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Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/<= /a>.
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