220 34038 article Path: news.gmane.org!.POSTED!not-for-mail From: Patrice Roy Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: std::vector::expand_uninitialized Date: Mon, 21 Aug 2017 21:19:43 -0400 Lines: 98 Approved: news@gmane.org Message-ID: References: <405bc3a4-4fbf-41af-b213-b24894ba2f6e@isocpp.org> <0304ee31-d873-25a5-1ff9-3364e76dff67@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="001a114c71f8f034dc05574d6319" X-Trace: blaine.gmane.org 1503364788 31444 195.159.176.226 (22 Aug 2017 01:19:48 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 22 Aug 2017 01:19:48 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDSZXMHWZIKBBMEN53GAKGQE4T56UQI@isocpp.org Tue Aug 22 03:19:41 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw0-f200.google.com ([209.85.161.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1djxr1-0007fP-K2 for gclcip-std-proposals@m.gmane.org; Tue, 22 Aug 2017 03:19:39 +0200 Original-Received: by mail-yw0-f200.google.com with SMTP id q72sf132899043ywg.15 for ; Mon, 21 Aug 2017 18:19:46 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1503364786; cv=pass; d=google.com; s=arc-20160816; b=NH5JUolDIoj31qf8TShDQ34i7hL7WZVlQ48GxJwSQh0hwaxkxFd1Ug8/1TZgkHjHVV ytLTjiumOo0me8kDkjXkdbfCo8kcE0WDiyUby839WDKGnIZRcKho1omEi1cS+4yvI8ma aS/aRl5Gwda1M2Trbks9qs2WPpVbepX/x4YDE5PYgUYpef1r4jF4y370p6ogcG+Ldvl9 LzUdaSgmYzD7CoHlhLxeDdEkwcaV+UlRWB+fx+rvLzjwSY0dyU0FfSoqCn80vsaEuWu/ Inak6emBlNxxz0y2XiJ2aBoNtf0KD0ELfjJ1nF4SSxdFncAR62P//kUJVYXeTyfgMGbG nKEQ== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post :list-id:mailing-list:precedence:reply-to:to:subject:message-id:date :from:references:in-reply-to:mime-version:arc-authentication-results :arc-message-signature:dkim-signature:arc-authentication-results; bh=sLFAUUqXnRm1vRWe2fFnA3IOdCypnFZvJxtDF0aWzFI=; b=L0d6b2c1u4T0DNlXK4T4n9QA/OEfBjQRweS9QrdUBR4eWPEnMuR6oMKDxHKoYomftE HT2WhmmtSlMIL3zjvUxQFR/nWaVihOU2gA1Q+TQ7XXpKo+YvYhraWu0HvYd2hRw+n5W9 vKPtoUMIlfHutCRMkN7hTBlyuDFRGOVZ7lgZbYeAwr544iYLvyElR4dKWwl0G+uc/dD0 rdckY+qdeHZU8IYJfM2DTaxPBIJNjSe/jmJj50D8IGoADunGRsXBp5uClIyiAKQGGotm kmg1dSpK+LauPkwIrn1Q11bTI9kJVCKo9yqNzd52+gvyPU5jNbSuimWpiRtQK+hpETQy IBDA== ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=oCokBRN/; spf=pass (google.com: domain of patricer@gmail.com designates 2607:f8b0:4002:c05::236 as permitted sender) smtp.mailfrom=patricer@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject: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=sLFAUUqXnRm1vRWe2fFnA3IOdCypnFZvJxtDF0aWzFI=; b=hq6T4LMs3dKpshUgOljXSXEVEBX2jK9naE2t9q1PXdA9MipkyZ+g2Z0PWSPwaXfaS1 RuovyqMvjJ76218D6GMtcbrDx11JBEmNrEbL91uteZC5m8mBGsclof2KAsPYPs0weQQq DEsM/6JjgTapyLAsTkHZYsTGjejOYssTiL2GVEOrmnQeF40mcAPp1puGNlR2fZEIUnf2 3JIqWAnE/K1aL13bxgZch+rjJvro6OkzQT9x7m02r62lLG6tQi1lwbSYGYvKRjKae1YC i5CPaY7aYDfwa0bfNk2gJD/TURD5QLH8DmZTJx0IQfSUkH51Jj9aMA87Km1kAgB7tdUG Gj6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject: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=sLFAUUqXnRm1vRWe2fFnA3IOdCypnFZvJxtDF0aWzFI=; b=tJq5CH0lxpw60s7NtkPue/EVahk6HZYVhOH7SB8J2AbWHrYpPyBjwJCNjuPNDjiJ1E /HrHKqC8oetakYHf8cXd2zK6M/okwWmhf1xmNfytSxazRPB/OeI9iAY+MJ+Wf6zXl2nr HZfPzQa5/mYcnw/dq0uuZBpD0kmoJuKqZvkJBXWRBsRKiOt0Ib9xBvBi1/AlU9zPU/7m d9P2uBOVCvWOZ2MRYpiVWcuBTYeSapE//FdZdQAD78s9MNB8fAZhfimzjXVFt+7aMKii sP/TjfWKpCjIQawU4hu9pzRp2nzsvOKSdB87dcEv8wdtj603XT822EgqupTnpQR1DFh0 k1Rw== X-Gm-Message-State: AHYfb5i2JunpXycvOuNb7Lv73kmNXGP+AZM+/2R+K0crJInwm2a4kK29 3ELzIl9NcZKWwELg X-Received: by 10.129.163.71 with SMTP id a68mr13908751ywh.95.1503364786073; Mon, 21 Aug 2017 18:19:46 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.36.192.65 with SMTP id u62ls6538003itf.2.gmail; Mon, 21 Aug 2017 18:19:44 -0700 (PDT) X-Received: by 10.37.45.94 with SMTP id s30mr16653431ybe.321.1503364784756; Mon, 21 Aug 2017 18:19:44 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1503364784; cv=none; d=google.com; s=arc-20160816; b=gCnzZ+FF8Bt6j0ZdLXknCXDkskrxvo2GOYLaHknlP+ulpttl56LdcJNC+0cHOGRbRm knDsOViTqejdZ0c2NQZtMDgm6ZU/EX4F1XXNwiIwCEZ9SPRu9qw6IQ2y75WVE7Oal+JK ogVpo9uLzf83qEKWrcLUWR4ZTCT1ov2PFUnoev6fRYL70DhTJX/E3oy3WzrlDg6iO0eA 4GxEXmjF2Ea94PybADKzcKocshtllISXs17Wd7fkUjDi/8PsWk7p9vFqBk+KYJrZJiMB 1IZU1roigMAuCRiv1MAq6VdBWYt9gwNJGkFwa/BwCilTnyBw8n9hEF7PE4Y7uC9HihSd 8pfA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=to:subject:message-id:date:from:references:in-reply-to:mime-version :dkim-signature:arc-authentication-results; bh=MAqjXB+eAhYcVzWwFTebtCsECFrOfbJGn7dtUuFpzN4=; b=T8/lmHyCpPDGPYNAh6RoA+QM0FUfKTeZ7xDGA68JJIYk5AE3jo0bxDtMkJjRU7TctE 6S1Ph7x1d/oKKzmczLzEjb1IUTXCZT6AFXqyiRplSGS3Kc4c3VzpNh4/6192r0nAavzO j5TsZEPPTsxQ+mWY8QGDNME71zXZflwKp6MXGdbz7/pcTS0g0Kb1BEkm9DPfEfnPfpYN 5wGDW1HKsvCfePeOxhBU8xDnOfeDaSVzjznv/VNOOeg6+PzCVxQYyJ5G9torqYkXiiQd nz6eO3TtsE0IPrcitnJ60T+x+g1NBL1CALVQ/LVV/uQTJfRKBMNiCyPJQWKjYc+2C2pK zDvg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=oCokBRN/; spf=pass (google.com: domain of patricer@gmail.com designates 2607:f8b0:4002:c05::236 as permitted sender) smtp.mailfrom=patricer@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.com Original-Received: from mail-yw0-x236.google.com (mail-yw0-x236.google.com. [2607:f8b0:4002:c05::236]) by mx.google.com with ESMTPS id o12si3515588ywi.677.2017.08.21.18.19.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 21 Aug 2017 18:19:44 -0700 (PDT) Received-SPF: pass (google.com: domain of patricer@gmail.com designates 2607:f8b0:4002:c05::236 as permitted sender) client-ip=2607:f8b0:4002:c05::236; Original-Received: by mail-yw0-x236.google.com with SMTP id s143so100511947ywg.1 for ; Mon, 21 Aug 2017 18:19:44 -0700 (PDT) X-Received: by 10.37.58.130 with SMTP id h124mr631659yba.281.1503364784336; Mon, 21 Aug 2017 18:19:44 -0700 (PDT) Original-Received: by 10.37.195.193 with HTTP; Mon, 21 Aug 2017 18:19:43 -0700 (PDT) In-Reply-To: <0304ee31-d873-25a5-1ff9-3364e76dff67@gmail.com> X-Original-Sender: patricer@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=oCokBRN/; spf=pass (google.com: domain of patricer@gmail.com designates 2607:f8b0:4002:c05::236 as permitted sender) smtp.mailfrom=patricer@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=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:34038 Archived-At: --001a114c71f8f034dc05574d6319 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable +1. Really looks like a reserve() use-case to me. 2017-08-21 4:29 GMT-04:00 Jonathan M=C3=BCller : > On 20.08.2017 22:22, Ryan Nicholl wrote: > >> My motivating example consists of a serialization routine. Ideally, the >> serialization routine would expand the vector uninitialized and then wri= te >> the data in. This can't be done however, because the resize function wri= tes >> 0s to the data thanks to the default allocator's construct method. >> > > Could you clarify why reserve + push_back() doesn't work here? > > -- > 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. > To view this discussion on the web visit https://groups.google.com/a/is > ocpp.org/d/msgid/std-proposals/0304ee31-d873-25a5-1ff9- > 3364e76dff67%40gmail.com. > --=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. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/CAKiZDp151PprK6Q_Gajnyh0URotphRK98M154jjPQEjAUOk= X4Q%40mail.gmail.com. --001a114c71f8f034dc05574d6319 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
+1. Really looks like a reserve() use-case to me.

2017-08-21 4:29 = GMT-04:00 Jonathan M=C3=BCller <jonathanmueller.dev@gmail.com<= /a>>:
On 20.08= ..2017 22:22, Ryan Nicholl wrote:
My motivating example consists of a serialization routine. Ideally, the ser= ialization routine would expand the vector uninitialized and then write the= data in. This can't be done however, because the resize function write= s 0s to the data thanks to the default allocator's construct method.

Could you clarify why reserve + push_back() doesn't work here?

--
You received this message because you are subscribed to the Google Groups &= quot;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.
To view this discussion on the web visit https://groups.google.com= /a/isocpp.org/d/msgid/std-proposals/0304ee31-d873-25a5-1ff9-= 3364e76dff67%40gmail.com.

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+unsubscribe@isocpp.org.
To post to this group, send email to std-proposals@isocpp.org.
To view this discussion on the web visit htt= ps://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAKiZDp151PprK6Q_= Gajnyh0URotphRK98M154jjPQEjAUOkX4Q%40mail.gmail.com.
--001a114c71f8f034dc05574d6319-- .