220 14096 <3d0ab5b0-73d9-434a-9ae4-cd47d8275590@isocpp.org> article Path: news.gmane.org!not-for-mail From: Myriachan Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: #pragma once Date: Tue, 21 Oct 2014 12:29:21 -0700 (PDT) Lines: 66 Approved: news@gmane.org Message-ID: <3d0ab5b0-73d9-434a-9ae4-cd47d8275590@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_3360_662072251.1413919761655" X-Trace: ger.gmane.org 1413919777 32373 80.91.229.3 (21 Oct 2014 19:29:37 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 21 Oct 2014 19:29:37 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDKLT4PURQHRBFHITKRAKGQE627WBLQ@isocpp.org Tue Oct 21 21:29:27 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qa0-f71.google.com ([209.85.216.71]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Xgf7V-0002d2-NT for gclcip-std-proposals@m.gmane.org; Tue, 21 Oct 2014 21:29:25 +0200 Original-Received: by mail-qa0-f71.google.com with SMTP id cm18sf4246012qab.2 for ; Tue, 21 Oct 2014 12:29:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id: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=xUX1V7lJ1AfyX7cSbcgBppKjz2CFBDjDZg9QAAs6U/c=; b=qR8zxe4TtVDkXqHTsKU+tcbt3EAWXejT4W0fRL3/25sBdcZ63aLVDvzJc+UvVof/bV LvuUsgrf+dKNB8qxheSZt0AIVU5XBz5t8uUI2E/XGWm4tdcLyBlWZOLkWXCIK0nnW7Yg Q7TAyKwqkV9z3d7p7VKH25WP4FFmowW3Kf/xL+dy4zj6UHdvfAIU3grX1hMHCBo95xX8 eiM95qJpNViQmWzSSmdQHi1cL75RNORMVOEbw3n+Xowmb8sH7tFR30wba32L876wbwKP 4S/11M9Pg8p2lWBZ5/onBy0G0Av1fz+yjrS815xzj+0QGavQZWd1uGvrmU3zUqqTlWzn 3LPQ== 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: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=xUX1V7lJ1AfyX7cSbcgBppKjz2CFBDjDZg9QAAs6U/c=; b=K0ppal5MOan9RD2ZSnJs9bew49/G8v+Mt99MUeh0W+qViL7GJWIxoU9hvL029GvVQk /fkZED54OVY8FP4nqCDoStUW0uRGN2Eq/k5rT/Fb+1PXAJaQIm8ouE0O1h1mjY7pLwtg HKrhKWKO8lJYFplxU7v/+LMzpPzKmXwdqegeVQZJWqIYezYlRA8KihFk99K5yVDINSv9 DgBPIUyc3uDmouQqPngLUba8qAaQkfcn4tXmC1yWoRctvxAthNo0OdekbdZFT03Sy2RQ PkEeRLqZYmlioLPJDeejCTGlbpiMQN+FG+juVXictJRfyWCXbTk0javN7+vSaNPwXI2+ GX9w== X-Gm-Message-State: ALoCoQkLl8z00hgKrpIp1ABFAKFqOjcBq+Zn3t+O7HlEfMxjaYEk+oXtEfq0hesvT6A3/bHUo33V X-Received: by 10.236.36.66 with SMTP id v42mr12961265yha.10.1413919764964; Tue, 21 Oct 2014 12:29:24 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.29.72 with SMTP id d69ls319440iod.53.gmail; Tue, 21 Oct 2014 12:29:23 -0700 (PDT) X-Received: by 10.51.16.65 with SMTP id fu1mr5937igd.10.1413919763731; Tue, 21 Oct 2014 12:29:23 -0700 (PDT) X-Original-Sender: myriachan@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:14096 Archived-At: ------=_Part_3360_662072251.1413919761655 Content-Type: text/plain; charset=UTF-8 I think that #pragma once should be standardized - at least partially/optionally/conditionally-supported. Every major compiler implements it with identical or nearly-identical semantics. Defining what it means for a file to be a repeat is rather simple: On platforms supporting symlinks and hard links, use unique inode numbers (+ device if needed). On other platforms, use the filename. Compilers may assume that files don't change while compiling (i.e. if the filename matches, it can be assumed to be identical). On platforms where there exist special links to the same or parent directory, like "./" or "../" on NT and POSIX, this assumption can be extended to collapse these. By the way, why don't _Pragma and #line support concatenating multiple strings in their respective string parameters? Melissa -- --- 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_3360_662072251.1413919761655 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I think that #pragma once should be standardized - at least partially/opti= onally/conditionally-supported.  Every major compiler implements it wi= th identical or nearly-identical semantics.

Defining what it means f= or a file to be a repeat is rather simple: On platforms supporting symlinks= and hard links, use unique inode numbers (+ device if needed).  On ot= her platforms, use the filename.  Compilers may assume that files don'= t change while compiling (i.e. if the filename matches, it can be assumed t= o be identical).  On platforms where there exist special links to the = same or parent directory, like "./" or "../" on NT and POSIX, this assumpti= on can be extended to collapse these.

By the way, why don't _Pragma and #line support concatenating= multiple strings in their respective string parameters?

Melissa
=

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