220 18339 article Path: news.gmane.org!not-for-mail From: David Krauss Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Use cases for dyn_array Date: Tue, 02 Jun 2015 01:33:09 +0800 Lines: 110 Approved: news@gmane.org Message-ID: References: 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=_F2B9B983-B131-4BAA-96B1-410AC3130190" X-Trace: ger.gmane.org 1433180025 10389 80.91.229.3 (1 Jun 2015 17:33:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 1 Jun 2015 17:33:45 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBAABB3NOWKVQKGQEHEB63TA@isocpp.org Mon Jun 01 19:33:36 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ig0-f200.google.com ([209.85.213.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YzTag-00062w-SK for gclcip-std-proposals@m.gmane.org; Mon, 01 Jun 2015 19:33:35 +0200 Original-Received: by igbjd9 with SMTP id jd9sf166878508igb.2 for ; Mon, 01 Jun 2015 10:33:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:content-type:message-id:mime-version :subject:date:references:to:in-reply-to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=0q0AttMRfyg9rBA+lspJthgK+utmJI2TnlCxo9ka+s8=; b=HOy/ZH0BfZsozz0N9husfzJwfhJ6IbpVBg+gCag1ZCUqNJ4DcIgAc1zegJCiQ+LKbH 2K8olhklGInxDOWcS5KjcHd7rS6UirhlClxzu2W2caVt5bW8rHoxKuHwpcUIhHZImPq/ gjjxNndLdsfF59tBra8y3XZRztXFuJ0xaeAKjv1hgJlABhLGTDd4At+zQRtV62MLozKp w/KZl0ru+ol0D3Uo92QJyUJ83VGb7dzJgiil5jhV1b3Z8ZTmVX9m4qvGWoUoZ7nGSecf ws8v4jwu7cXN48ZkW0t5nb/2MtFwFftwJVOAHbWFSpuQRQPbwzxNudHlIq9vCBt3t8FT NHcA== X-Gm-Message-State: ALoCoQmCr8W7T8odxH6WucGFqpva9jfNmX3+Kqzxt6AKPO85Mk/SKxvLvymylTUM6dne8ct65DDb X-Received: by 10.182.16.163 with SMTP id h3mr30492751obd.14.1433180014060; Mon, 01 Jun 2015 10:33:34 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.87.68 with SMTP id v4ls122303igz.14.gmail; Mon, 01 Jun 2015 10:33:33 -0700 (PDT) X-Received: by 10.70.138.38 with SMTP id qn6mr41764986pdb.119.1433180013332; Mon, 01 Jun 2015 10:33:33 -0700 (PDT) Original-Received: from nk11p04mm-asmtp002.mac.com (nk11p04mm-asmtpout002.mac.com. [17.158.236.237]) by mx.google.com with ESMTPS id 7si22426656pdg.139.2015.06.01.10.33.33 for (version=TLSv1.2 cipher=AES128-GCM-SHA256 bits=128/128); Mon, 01 Jun 2015 10:33:33 -0700 (PDT) Received-SPF: pass (google.com: domain of potswa@mac.com designates 17.158.236.237 as permitted sender) client-ip=17.158.236.237; Original-Received: from [172.20.10.2] (unknown [121.54.54.152]) by nk11p04mm-asmtp002.mac.com (Oracle Communications Messaging Server 7.0.5.35.0 64bit (built Dec 4 2014)) with ESMTPSA id <0NPA00CX40RA0230@nk11p04mm-asmtp002.mac.com> for std-proposals@isocpp.org; Mon, 01 Jun 2015 17:33:16 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.14.151,1.0.33,0.0.0000 definitions=2015-06-01_07:2015-05-29,2015-06-01,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=1 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1412110000 definitions=main-1506010221 In-reply-to: X-Mailer: Apple Mail (2.2098) X-Original-Sender: potswa@mac.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of potswa@mac.com designates 17.158.236.237 as permitted sender) smtp.mail=potswa@mac.com; dmarc=pass (p=NONE dis=NONE) header.from=mac.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:18339 Archived-At: --Apple-Mail=_F2B9B983-B131-4BAA-96B1-410AC3130190 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 > On 2015=E2=80=9306=E2=80=9302, at 1:20 AM, Matthew Fioravante wrote: >=20 > unique_ptr has some limitations: >=20 > 1) It doesn't store the size of the block, so you need to either keep tra= ck of it separately or write a wrapper type, which is essentially what I'm = talking about. > 2) It only allows you to construct the objects with the default construct= or, which can be very limiting, especially for non-copy/non-move types. Both of these can be solved using a custom allocator. I've wondered about the omission of std::allocate_unique. Has it ever come = up? There would need to be a generic allocator-to-deleter adapter, which should= be generally useful and not too difficult. The general case would need to = store an element count, because that is expected by allocator::deallocate. = This could be publicly accessible. --=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=_F2B9B983-B131-4BAA-96B1-410AC3130190 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=UTF-8
On 2015=E2=80=9306= =E2=80=9302, at 1:20 AM, Matthew Fioravante <fmatthew5876@gmail.com> wrote:

unique_ptr<T[]> h= as some limitations:

1) It doesn't store the size of the block, so you nee= d to either keep track of it separately or write a wrapper type, which is e= ssentially what I'm talking about.
= 2) It only allows you to construct the objects with the default construct= or, which can be very limiting, especially for non-copy/non-move types.

B= oth of these can be solved using a custom allocator.
<= br class=3D"">
I've wondered about the omission of std::allocate_unique. Has it ever com= e up?

There would= need to be a generic allocator-to-deleter adapter, which should be general= ly useful and not too difficult. The general case would need to store an el= ement count, because that is expected by = allocator::deallocate. This could be publicly accessible.

--

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