From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756727Ab3K0PqH (ORCPT ); Wed, 27 Nov 2013 10:46:07 -0500 Received: from mail-bk0-f54.google.com ([209.85.214.54]:62719 "EHLO mail-bk0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751749Ab3K0PqF (ORCPT ); Wed, 27 Nov 2013 10:46:05 -0500 Date: Wed, 27 Nov 2013 16:46:00 +0100 From: Ingo Molnar To: Peter Zijlstra Cc: Steven Rostedt , Juri Lelli , tglx@linutronix.de, mingo@redhat.com, oleg@redhat.com, fweisbec@gmail.com, darren@dvhart.com, johan.eker@ericsson.com, p.faure@akatech.ch, linux-kernel@vger.kernel.org, claudio@evidence.eu.com, michael@amarulasolutions.com, fchecconi@gmail.com, tommaso.cucinotta@sssup.it, nicola.manica@disi.unitn.it, luca.abeni@unitn.it, dhaval.giani@gmail.com, hgu1972@gmail.com, paulmck@linux.vnet.ibm.com, raistlin@linux.it, insop.song@gmail.com, liming.wang@windriver.com, jkacur@redhat.com, harald.gustafsson@ericsson.com, vincent.guittot@linaro.org, bruce.ashfield@windriver.com Subject: Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks. Message-ID: <20131127154600.GC26095@gmail.com> References: <1383831828-15501-1-git-send-email-juri.lelli@gmail.com> <1383831828-15501-9-git-send-email-juri.lelli@gmail.com> <20131120163318.10253e43@gandalf.local.home> <5295F711.5010708@gmail.com> <20131127091647.4e16ce53@gandalf.local.home> <20131127142649.GC13532@twins.programming.kicks-ass.net> <20131127143435.GD25043@gmail.com> <20131127145837.GE16796@laptop.programming.kicks-ass.net> <20131127153519.GA26095@gmail.com> <20131127154015.GG789@laptop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20131127154015.GG789@laptop.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Peter Zijlstra wrote: > On Wed, Nov 27, 2013 at 04:35:19PM +0100, Ingo Molnar wrote: > > So why does GCC then behave like this: > > I think because its a much saner behaviour; also it might still be the > spec actually says this, its a somewhat opaque text. > > Anyway, yes GCC seems to behave as we 'expect' it to; I just can't find > the language spec actually guaranteeing this. So from C99 standard §6.7.8 (Initialization)/21: "If there are fewer initializers in a brace-enclosed list than there are elements or members of an aggregate, or fewer characters in a string literal used to initialize an array of known size than there are elements in the array, the remainder of the aggregate shall be initialized implicitly the same as objects that have static storage duration." static initialization == zeroing in this case. Thanks, Ingo