From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756196AbYEXOgg (ORCPT ); Sat, 24 May 2008 10:36:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753650AbYEXOg3 (ORCPT ); Sat, 24 May 2008 10:36:29 -0400 Received: from gw.goop.org ([64.81.55.164]:37813 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752499AbYEXOg2 (ORCPT ); Sat, 24 May 2008 10:36:28 -0400 Message-ID: <483827CE.9080200@goop.org> Date: Sat, 24 May 2008 15:35:58 +0100 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Sam Ravnborg CC: "H. Peter Anvin" , Steve French , lkml Subject: Re: kernel coding style for if ... else which cross #ifdef References: <524f69650805231211r315be4e4u5890aa0f914bcb4f@mail.gmail.com> <48374D3F.1080502@zytor.com> <20080524054301.GA3773@uranus.ravnborg.org> <4837AAE2.9090102@zytor.com> <20080524064201.GA4133@uranus.ravnborg.org> <4837E89D.9040008@goop.org> <20080524112704.GA7292@uranus.ravnborg.org> In-Reply-To: <20080524112704.GA7292@uranus.ravnborg.org> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sam Ravnborg wrote: > I assume you wanted to say: > >> #undef CONFIG_FOO >> #define CFG_FOO 1 >> #define CONFIG_FOO_MODULE >> #define CFG_FOO_MODULE 1 >> > Because then the CONFIG_* is not changed > and we do not want to change that. > Yeah, I didn't intend to change the meaning of CONFIG_FOO. > I'm not fully convinced about: > >> #define CFG_FOO 1 >> > But on the other hand it is only in odd > cases we distingush between built-in and module. > So it makes most sense. > I think CONFIG_ and CFG_ should be exact parallels, so if CONFIG_FOO is undefined, CFG_FOO should be 0. >> Not sure what CFG_* should be for string/numeric options. Probably "1" >> if the value is defined, "0" if not, with CONFIG_* being the actual >> value (so a CONFIG_ value of 0 is distinguishable from not defined). >> > For non-boolean/tristate values we simply skip CFG_ values - thats > the most simple approach. I suppose, but it might be useful to know whether a constant is present: if (CFG_THINGY_LIMIT && x > CONFIG_THINGY_LIMIT) {...} (which fails if CONFIG_THINGY_LIMIT is undefined, so I guess it still doesn't work very well). J