Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763971AbXF1MK2 (ORCPT ); Thu, 28 Jun 2007 08:10:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759308AbXF1MKT (ORCPT ); Thu, 28 Jun 2007 08:10:19 -0400 Received: from mx1.redhat.com ([66.187.233.31]:43400 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759045AbXF1MKR (ORCPT ); Thu, 28 Jun 2007 08:10:17 -0400 Date: Thu, 28 Jun 2007 08:08:03 -0400 From: Jakub Jelinek To: Kyle Moffett Cc: Matthew Wilcox , Adrian Bunk , LKML Kernel , David Woodhouse , david@lang.hm, Andi Kleen , linux-arch@vger.kernel.org Subject: Re: Userspace compiler support of "long long" Message-ID: <20070628120803.GI7012@devserv.devel.redhat.com> Reply-To: Jakub Jelinek References: <467b0bf2.Xfs7T8Ys4nY9ZNLW%Joerg.Schilling@fokus.fraunhofer.de> <1182483527.10524.31.camel@shinybook.infradead.org> <20070622150038.GN23017@stusta.de> <20070627154046.GN1094@stusta.de> <468287a8.spBb6PdAZ4QV0j2Y%Joerg.Schilling@fokus.fraunhofer.de> <20070627173240.GR1094@stusta.de> <20070628035754.GB22063@parisc-linux.org> <6B8385EC-8CD4-4E8B-94EF-293A02A62189@mac.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6B8385EC-8CD4-4E8B-94EF-293A02A62189@mac.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1744 Lines: 40 On Thu, Jun 28, 2007 at 07:53:51AM -0400, Kyle Moffett wrote: > On Jun 27, 2007, at 23:57:54, Matthew Wilcox wrote: > >On Wed, Jun 27, 2007 at 06:30:52PM -0400, Kyle Moffett wrote: > >>Then all 64-bit archs have: > >>typedef signed long __s64; > >>typedef unsigned long __u64; > >> > >>While all 32-bit archs have: > >>typedef signed long long __s64; > >>typedef unsigned long long __u64; > > > >include/asm-parisc/types.h:typedef unsigned long long __u64; > > > >For both 32 and 64-bit. > > > >include/asm-sh64/types.h:typedef unsigned long long __u64; > >include/asm-x86_64/types.h:typedef unsigned long long __u64; > > > >So that's three architectures that violate your first assertion. > > Oh, ok, that makes it even easier to say this with certainty: > Changing the other 64-bit archs to use "long long" for their 64-bit > numbers will not cause additional warnings. I'm also almost certain > there are no architectures which use "long long" for 128-bit > integers. (Moreover, I can't find hardly anything which does 128-bit > integers at all). unsigned long and unsigned long long have the same size, precision and alignment on all LP64 arches, that's true. But they have different ranks and more importantly they mangle differently in C++. So, whether some user exposed type uses unsigned long or unsigned long long is part of the ABI, whether that's size_t, uintptr_t, uint64_t, u_int64_t or any other type, you can't change it without breaking the ABI. Jakub - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/