From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: Re: [patch] fix void* arithmetic Date: Tue, 29 Aug 2006 17:26:28 -0400 Message-ID: <44F4B104.1000301@garzik.org> References: <1156883088.29858.69.camel@basalt.austin.ibm.com> <1156885583.5190.9.camel@localhost.localdomain> <1156886315.29858.78.camel@basalt.austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1156886315.29858.78.camel@basalt.austin.ibm.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Hollis Blanchard Cc: xen-ppc-devel , xen-devel , Ian Campbell List-Id: xen-devel@lists.xenproject.org Hollis Blanchard wrote: > On Tue, 2006-08-29 at 22:06 +0100, Ian Campbell wrote: >> On Tue, 2006-08-29 at 15:24 -0500, Hollis Blanchard wrote: >>> Hi Ian, I needed the following patch to avoid lots of these warnings: >>> elf.c:238: warning: pointer of type `void *' used in arithmetic >>> >>> Fix void* arithmetic warnings. >>> Signed-off-by: Hollis Blanchard >> Looks like PPC is the only arch using -Wpointer-arith, is there a reason >> for that? > > Is there are reason the other architectures *aren't* using it? > > We have some extra warnings enabled because they've helped us in the > past (such as -Wshadow). Given that we're just playing janitor for > everyone else's code though, I think we're about to abandon that one. Pointer arith is quite valid on void pointers, when using gcc and most other modern compilers. Point of fact, any Linux kernel-related code REQUIRES that void* arith be valid, and not cause warnings. As we see from your patch, all a cast to char* does is complicate the code, for zero gain. Jeff