220 33851 <188dc31c-df5e-4fe1-ad85-847d3d732880@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Niall Douglas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: string_view for fstream::open() Date: Fri, 11 Aug 2017 15:29:22 -0700 (PDT) Lines: 65 Approved: news@gmane.org Message-ID: <188dc31c-df5e-4fe1-ad85-847d3d732880@isocpp.org> References: <3456831.gsseCm4DuK@tjmaciei-mobl1> <6240d6af-a518-4788-a56f-b7d0c8976dc4@isocpp.org> <01739e89-fc83-428b-94d5-e4e06927cc80@isocpp.org> <25b20004-c1b3-4844-b957-ef57e043b533@isocpp.org> <15b49197-b38b-47be-aefb-0786af7635f2@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_2478_1398369499.1502490562918" X-Trace: blaine.gmane.org 1502490572 20676 195.159.176.226 (11 Aug 2017 22:29:32 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 11 Aug 2017 22:29:32 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDGKFT5YZADRBQ67XDGAKGQETITSXKA@isocpp.org Sat Aug 12 00:29:23 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-it0-f71.google.com ([209.85.214.71]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dgIQg-0004Wn-F1 for gclcip-std-proposals@m.gmane.org; Sat, 12 Aug 2017 00:29:18 +0200 Original-Received: by mail-it0-f71.google.com with SMTP id 77sf55422870itj.4 for ; Fri, 11 Aug 2017 15:29:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; 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; bh=VmXUFXJCFSE1eDZ2qjMmvgpWDDBLm1y+pOc+tXKiiL4=; b=0H6aITp+aEeC3fERfpGXUi+aiwdVSS6fcfG0V9YhG1pKyVlg4tAYO4oXY3lrKq3J80 pC0HPWmSNnEqQGloa5LE9sWR0mMnclUlWzLLvLrTl8oVEVaUdPLnO3ihgGbP1TCEtXb4 V3eWxgDewmIdtnZZkmqQyq3qjS2VMmHCxAm0rpm9xzgnwe+HTFN08140PVc0kjS8PdJ2 pcnccAm5gFWNXVWp81yh13bZa9pNixXRmCx6NApK7jfWSE49LsPPPY6VMAtPvSewTycG PCm8aOMjhPIhDluwdQpum52CY1BVjRFsJ3rOIxgleIs7AQAv0gcyGIc79XzTT8GusRuz 4wug== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; 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; bh=VmXUFXJCFSE1eDZ2qjMmvgpWDDBLm1y+pOc+tXKiiL4=; b=JW5MiQwbk+j5YzfXRQecAIDaaoGhuuPGXkTbqgyjLJ0ph2y/OQ+cwwEm+mmoDAKl30 yx4mVIL4Sd9BOniqzcKj/xTuAcp9SEq1tXZtA1SyXaZmsoKtHOxiEG0a+s95XoQRtaCX o4yD9522OiZrxJceObzed+m0r68aJZfIyxRzB2hiDpU3TUyJViAgWFxe/lsRxldUy8HL Fz5cKjsawoTFFvFMmK2TY3jsVBBYnzAtAhKCageA6tVxHHkDrV6gKLufWt9CC5nOQJFC cdwAfzKPoU+eID3O/ilVGDIjpnfvduR6MfZEC7yTdbH0rqrhV/0+WTPXk3ljL6OM5gp1 NIjw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; 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:x-spam-checked-in-group:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=VmXUFXJCFSE1eDZ2qjMmvgpWDDBLm1y+pOc+tXKiiL4=; b=hgiFs9j8i0ghyJvinjS50mciEKGkmoueIUqHZ/wa2pPfVbcVWq90OYZqwcaD0Uuil0 0/wusdzRY4Q5NCaxCqJECT1S3TK1TQt/aS8weQ8rDxs+LS1KwZmvKF2AZUn3pmhI4C+e U8Vg7LIDSq9N/OOKmDFhs/VHvO1lMTWnzWnyze5wBSr7WEuvVTnQ7odlsS0gBKoWGuCf 3bpxfQEXPa0nxKus2PkYSOlMopH1BoNkfGDxYL/mgdt8LlZIgZC8ssAYfXfltppnf9yu sGUBdZ154aIwpVqjMEb2mBCKdH27Sp1agMSgnFfFsbLx5Q/xdzzjUF3ZYapZrcDrZ7MF nFZQ== X-Gm-Message-State: AHYfb5jBIv9pWkWiv1oS7ChNdjrV1kpFo3BhUIWoIDHz+EdI4OwhqcwM JnHYWLbubKeTXOys X-Received: by 10.36.1.136 with SMTP id 130mr127936itk.3.1502490564606; Fri, 11 Aug 2017 15:29:24 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.36.51.142 with SMTP id k136ls419642itk.7.gmail; Fri, 11 Aug 2017 15:29:23 -0700 (PDT) X-Received: by 10.31.160.13 with SMTP id j13mr109122vke.25.1502490563438; Fri, 11 Aug 2017 15:29:23 -0700 (PDT) In-Reply-To: <15b49197-b38b-47be-aefb-0786af7635f2@isocpp.org> X-Original-Sender: nialldouglas14@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:33851 Archived-At: ------=_Part_2478_1398369499.1502490562918 Content-Type: multipart/alternative; boundary="----=_Part_2479_1598270752.1502490562918" ------=_Part_2479_1598270752.1502490562918 Content-Type: text/plain; charset="UTF-8" > > > Or we can just have a single `filesystem::path` type, which you can get > views of with existing types. I prefer that option. > As already covered in great detail by now, if fed a string_view then one is mandated to memcpy the lot so it can be zero terminated before sending it to the file path consuming syscall. As much as open() is not a fast syscall, copying 32Kb needlessly makes a statistically noticeable difference. path_view eliminates that problem. Niall -- 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/isocpp.org/d/msgid/std-proposals/188dc31c-df5e-4fe1-ad85-847d3d732880%40isocpp.org. ------=_Part_2479_1598270752.1502490562918 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Or we can just have a single `filesystem::path` type, which yo= u can get views of with existing types. I prefer that option.

As already covered in great detail by now, i= f fed a string_view then one is mandated to memcpy the lot so it can be zer= o terminated before sending it to the file path consuming syscall.

As much as open() is not a fast syscall, copying 32Kb need= lessly makes a statistically noticeable difference. path_view eliminates th= at problem.

Niall
=C2=A0

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