From: "H. Peter Anvin" <hpa@zytor.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Tom Spink <tspink@gmail.com>,
Vegard Nossum <vegard.nossum@gmail.com>,
Sam Ravnborg <sam@ravnborg.org>,
Steve French <smfrench@gmail.com>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: kernel coding style for if ... else which cross #ifdef
Date: Sat, 24 May 2008 13:43:28 -0700 [thread overview]
Message-ID: <48387DF0.7000600@zytor.com> (raw)
In-Reply-To: <48387CCB.1030801@goop.org>
Jeremy Fitzhardinge wrote:
> Tom Spink wrote:
>> A thought occurred to me that we may be able to used some preprocessor
>> magic and do this:
>>
>> #define config_defined(x) CFGVAL_## x
>>
>> Which means that, if we get Kconfig to produce:
>>
>> #define CFGVAL_CONFIG_FOO 0
>> #define CFGVAL_CONFIG_VALUE_BAR 1
>> #define CFGVAL_CONFIG_VALUE_BAZ_MODULE 1
>>
>> We can use this:
>>
>> if (config_defined(CONFIG_FOO) && some_expr) {
>> panic("Oh no.");
>> }
>
> Well, in that case you could use Willy's magic hack:
>
> #define config_defined(x) (x - 0)
>
> Which isn't a bad alternative to defining a whole pile of new symbols...
>
That can *strongly* be argued with.
In particular, the use of #ifdef is crap to begin with. Using #if even
for the preprocessor makes it possible to trap misspellings.
-hpa
next prev parent reply other threads:[~2008-05-24 20:47 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-23 19:11 kernel coding style for if ... else which cross #ifdef Steve French
2008-05-23 20:42 ` Willy Tarreau
2008-05-23 20:49 ` Adrian Bunk
2008-05-23 21:05 ` Willy Tarreau
2008-05-23 23:03 ` H. Peter Anvin
2008-05-24 5:43 ` Sam Ravnborg
2008-05-24 5:42 ` H. Peter Anvin
2008-05-24 6:42 ` Sam Ravnborg
2008-05-24 10:06 ` Jeremy Fitzhardinge
2008-05-24 10:49 ` Adrian Bunk
2008-05-24 11:27 ` Sam Ravnborg
2008-05-24 14:35 ` Jeremy Fitzhardinge
2008-05-24 14:39 ` Willy Tarreau
2008-05-24 14:41 ` Jeremy Fitzhardinge
2008-05-24 14:46 ` Willy Tarreau
2008-05-24 15:36 ` Sam Ravnborg
2008-05-24 15:45 ` Jeremy Fitzhardinge
2008-05-24 15:57 ` Vegard Nossum
2008-05-24 16:02 ` Jeremy Fitzhardinge
2008-05-24 16:40 ` Tom Spink
2008-05-24 16:42 ` Tom Spink
2008-05-24 20:38 ` Jeremy Fitzhardinge
2008-05-24 20:43 ` H. Peter Anvin [this message]
2008-05-24 20:51 ` Jeremy Fitzhardinge
2008-05-24 20:54 ` H. Peter Anvin
2008-05-24 21:15 ` Jeremy Fitzhardinge
2008-05-25 23:57 ` Adrian Bunk
2008-05-26 0:27 ` H. Peter Anvin
2008-05-24 18:12 ` H. Peter Anvin
2008-05-24 18:12 ` H. Peter Anvin
2008-05-24 18:51 ` Sam Ravnborg
2008-05-24 18:08 ` H. Peter Anvin
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