Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932066AbXFRO1h (ORCPT ); Mon, 18 Jun 2007 10:27:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762004AbXFRO1a (ORCPT ); Mon, 18 Jun 2007 10:27:30 -0400 Received: from shawidc-mo1.cg.shawcable.net ([24.71.223.10]:29242 "EHLO pd2mo2so.prod.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750763AbXFRO13 (ORCPT ); Mon, 18 Jun 2007 10:27:29 -0400 Date: Mon, 18 Jun 2007 08:27:15 -0600 From: Robert Hancock Subject: Re: [patch] use __asm__ and __volatile__ in i386/arm/s390 byteorder.h In-reply-to: To: David Woodhouse Cc: Arnd Bergmann , Arjan van de Ven , Mike Frysinger , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, rmk@arm.linux.org.uk Message-id: <46769643.7010106@shaw.ca> MIME-version: 1.0 Content-type: text/plain; charset=UTF-8; format=flowed Content-transfer-encoding: 8BIT References: User-Agent: Thunderbird 2.0.0.4 (Windows/20070604) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1658 Lines: 34 David Woodhouse wrote: > On Mon, 2007-06-18 at 01:24 +0200, Arnd Bergmann wrote: >> On Monday 18 June 2007, Arjan van de Ven wrote: >>> On Sun, 2007-06-17 at 18:33 -0400, Mike Frysinger wrote: >>>> This changes asm() to __asm__() and volatile to __volatile__ so that these >>>> headers can be used with gcc's -std=c99. >>> hmm but the kernel doesn't use -std=c99... >> The byteorder headers are exported to user space through >> include/asm-generic/Kbuild.asm, and they are used by a number >> of other exported headers, so they should work with any >> gcc flags that a user might want to use. > > Even those headers which are exported are _still_ kernel headers¹. The > 'caveat emptor' principle still applies to them, and we don't have to be > _that_ anal about it. GNU extensions (and proper C types, for that > matter) should be acceptable, surely? If we expect userspace apps to include them, then I would vote for no, not for anything outside of #ifdef __KERNEL__ in exported headers. Keep in mind also that C++ apps may need to include these as well and those extensions don't always play well in C++ mode. (Last instance I ran into was the ioctl argument checking macros _IOR, _IOW, etc. that create non-compiling code if you use them in a C++ program.) -- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from hancockr@nospamshaw.ca Home Page: http://www.roberthancock.com/ - 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/