From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758065Ab2CVXDj (ORCPT ); Thu, 22 Mar 2012 19:03:39 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33212 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756364Ab2CVXDi (ORCPT ); Thu, 22 Mar 2012 19:03:38 -0400 Date: Thu, 22 Mar 2012 16:03:36 -0700 From: Andrew Morton To: Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= Cc: Lucas De Marchi , linux-kernel@vger.kernel.org, Greg KH Subject: Re: [PATCH] telephony/ixj: Fix warning about sequence points Message-Id: <20120322160336.66e9a88b.akpm@linux-foundation.org> In-Reply-To: <1332154664-10968-1-git-send-email-uwe@kleine-koenig.org> References: <1332154664-10968-1-git-send-email-uwe@kleine-koenig.org> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 19 Mar 2012 11:57:44 +0100 Uwe Kleine-K__nig wrote: > In the statement > > j->caplist[j->caps].handle = j->caps++; > > there is no sequence point between the usage of j->caps on the LHS of the > assignment and the incrementation on its RHS. So it's not defined in Standard C > if j->caps is already incremented when used on the LHS even though the postfix > ++ operator is used. To properly fix that the incrementation has to be done in > a seperate expression. > > This fixes: > drivers/telephony/ixj.c: In function ___add_caps___: > drivers/telephony/ixj.c:5930:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:5950:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:5954:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:5965:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:5976:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:5988:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:5998:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6003:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6008:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6013:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6019:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6026:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6031:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6036:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6041:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6049:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6057:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6065:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > drivers/telephony/ixj.c:6071:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point] > > Signed-off-by: Uwe Kleine-K__nig > --- > drivers/telephony/ixj.c | 57 +++++++++++++++++++++++++++++++--------------- fyi, ixj.c has been moved into staging/, with a view to removing it altogether. It will be sad to see it go - it has stood as a great example of what not to do ;) And no, I don't now how to find out if anyone is using it either.