From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] trunk r117846: Add macros to allocate temporary Lisp objects with alloca. Date: Tue, 09 Sep 2014 08:10:11 -0700 Organization: UCLA Computer Science Department Message-ID: <540F1853.40509@cs.ucla.edu> References: <540F0BCB.4030506@yandex.ru> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1410275467 21665 80.91.229.3 (9 Sep 2014 15:11:07 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 9 Sep 2014 15:11:07 +0000 (UTC) Cc: Emacs development discussions To: Dmitry Antipov , Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Sep 09 17:11:00 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XRN4F-0006r3-7P for ged-emacs-devel@m.gmane.org; Tue, 09 Sep 2014 17:10:51 +0200 Original-Received: from localhost ([::1]:50297 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XRN4E-0004ia-MJ for ged-emacs-devel@m.gmane.org; Tue, 09 Sep 2014 11:10:50 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:40594) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XRN3u-0004bA-G2 for emacs-devel@gnu.org; Tue, 09 Sep 2014 11:10:37 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XRN3m-0003xV-6j for emacs-devel@gnu.org; Tue, 09 Sep 2014 11:10:30 -0400 Original-Received: from smtp.cs.ucla.edu ([131.179.128.62]:57273) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XRN3m-0003xQ-19 for emacs-devel@gnu.org; Tue, 09 Sep 2014 11:10:22 -0400 Original-Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp.cs.ucla.edu (Postfix) with ESMTP id E2B06A60002; Tue, 9 Sep 2014 08:10:20 -0700 (PDT) X-Virus-Scanned: amavisd-new at smtp.cs.ucla.edu Original-Received: from smtp.cs.ucla.edu ([127.0.0.1]) by localhost (smtp.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 535KctMaOLGu; Tue, 9 Sep 2014 08:10:12 -0700 (PDT) Original-Received: from [192.168.1.9] (pool-71-177-17-123.lsanca.dsl-w.verizon.net [71.177.17.123]) by smtp.cs.ucla.edu (Postfix) with ESMTPSA id 3EF5039E8011; Tue, 9 Sep 2014 08:10:12 -0700 (PDT) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 In-Reply-To: <540F0BCB.4030506@yandex.ru> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 131.179.128.62 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:174118 Archived-At: Dmitry Antipov wrote: > No ideas why alignas (X) is designed in such a way. You'll have to ask the committee. :-) For C11, the C standardization committee decided to allow alignas only when declaring objects; alignas cannot be used in typedefs or in the definitions of structures. Emacs prefers alignas when it works, since alignas is standardized and is more likely to be portable, but for this particular feature (an aligned structure type) Emacs uses a GCC extension instead, since there's no way to do it in the standard. I'll try to review the code carefully soon.