From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 67317 invoked by alias); 12 Jan 2018 17:56:03 -0000 Mailing-List: contact libstdc++-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libstdc++-owner@gcc.gnu.org Received: (qmail 66752 invoked by uid 89); 12 Jan 2018 17:56:03 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS,URIBL_RED autolearn=ham version=3.3.2 spammy= X-Spam-User: qpsmtpd, 2 recipients X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 12 Jan 2018 17:56:02 +0000 Received: from nat-ies.mentorg.com ([192.94.31.2] helo=svr-ies-mbx-01.mgc.mentorg.com) by relay1.mentorg.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-SHA384:256) id 1ea3Ye-000424-4D from joseph_myers@mentor.com ; Fri, 12 Jan 2018 09:56:00 -0800 Received: from digraph.polyomino.org.uk (137.202.0.87) by svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) with Microsoft SMTP Server (TLS) id 15.0.1320.4; Fri, 12 Jan 2018 17:55:56 +0000 Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.86_2) (envelope-from ) id 1ea3YZ-00038r-TL; Fri, 12 Jan 2018 17:55:56 +0000 Date: Fri, 12 Jan 2018 17:56:00 -0000 From: Joseph Myers To: Torvald Riegel CC: Mike Crowe , Jonathan Wakely , , Subject: Re: [PATCH 2/5] libstdc++ futex: Use FUTEX_CLOCK_REALTIME for wait In-Reply-To: <1515763080.4439.129.camel@redhat.com> Message-ID: References: <20180107205532.13138-1-mac@mcrowe.com> <20180107205532.13138-3-mac@mcrowe.com> <20180109135053.GB5527@redhat.com> <20180109175419.aamg44vdbizhdoka@mcrowe.com> <1515763080.4439.129.camel@redhat.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-ClientProxiedBy: svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) To svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) X-SW-Source: 2018-01/txt/msg00063.txt.bz2 On Fri, 12 Jan 2018, Torvald Riegel wrote: > Another option might be to require a minimum glibc version on Linux, and > build libstdc++ for that. That would yield a minimum kernel version as > well, and we may can make use of other things in return such as syscall > wrappers. A minimum glibc version of course only applies when libstdc++ is being built with glibc - it can also be built with other C libraries using the Linux kernel (and some - at least uClibc - define __GLIBC__ to pretend to be some old glibc version). One thing to note regarding minimum glibc (or kernel) versions is it can be useful to use new GCC to build binaries to run on older systems - which means building new GCC as a cross compiler with a sysroot with an old glibc version in it. So the relevant question for establishing a minimum glibc or kernel version is not what systems people are using to develop GCC, but what systems they might want to deploy binaries built with current GCC onto. -- Joseph S. Myers joseph@codesourcery.com