From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS22989 209.51.188.0/24 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id AF6141F453 for ; Sun, 17 Feb 2019 20:07:03 +0000 (UTC) Received: from localhost ([127.0.0.1]:46066 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gvSiM-0001Yh-JK for normalperson@yhbt.net; Sun, 17 Feb 2019 15:07:02 -0500 Received: from eggs.gnu.org ([209.51.188.92]:45765) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gvSiJ-0001YQ-9P for bug-gnulib@gnu.org; Sun, 17 Feb 2019 15:06:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gvSiI-0008Dr-N1 for bug-gnulib@gnu.org; Sun, 17 Feb 2019 15:06:59 -0500 Received: from zimbra.cs.ucla.edu ([131.179.128.68]:52092) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gvSiI-0008Be-GC; Sun, 17 Feb 2019 15:06:58 -0500 Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id D41D3161365; Sun, 17 Feb 2019 12:06:54 -0800 (PST) Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id cHl5OzSMlCij; Sun, 17 Feb 2019 12:06:54 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 1A747161379; Sun, 17 Feb 2019 12:06:54 -0800 (PST) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id BOnYLXPwKxkc; Sun, 17 Feb 2019 12:06:54 -0800 (PST) Received: from [192.168.1.9] (cpe-23-242-74-103.socal.res.rr.com [23.242.74.103]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id E4DB71612FB; Sun, 17 Feb 2019 12:06:53 -0800 (PST) Subject: Re: Gnulib's alloca.h used even when there is a system header To: Eli Zaretskii References: <83ftsml4bl.fsf@gnu.org> From: Paul Eggert Organization: UCLA Computer Science Department Message-ID: <1c511ef7-ebdc-b34d-e6b0-2f79362ad981@cs.ucla.edu> Date: Sun, 17 Feb 2019 12:06:53 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <83ftsml4bl.fsf@gnu.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 131.179.128.68 X-BeenThere: bug-gnulib@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Gnulib discussion list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: bug-gnulib@gnu.org Errors-To: bug-gnulib-bounces+normalperson=yhbt.net@gnu.org Sender: "bug-gnulib" Eli Zaretskii wrote: > Gnulib decides to > generate its own alloca.h header even though there's a system header > alloca.h (and HAVE_ALLOCA_H is 1 in config.h). Why does it do that? > Isn't that dangerous? e.g., it could conflict with how the system > header defies 'alloca', no? This stuff is rickety, as it's built atop Autoconf's AC_FUNC_ALLOCA and that stuff hasn't changed in at least a decade. In the old days, some alloca implementations were broken and when in doubt it was better to replace the system alloca than to use it. Nowadays I doubt whether it matters much. In any event Autoconf and/or Gnulib patches to be more cautious about replacing alloca.h would be welcome.