Re: CVS commit: src/sys/sys

[Lourival Vieira Neto <lneto%netbsd.org@localhost>]

On Thu, Jul 17, 2014 at 3:14 PM, Marc Balmer <marc%msys.ch@localhost> wrote:
>
> Am 17.07.2014 um 16:55 schrieb Taylor R Campbell 
> <riastradh%NetBSD.org@localhost>:
>
>> Module Name:  src
>> Committed By: riastradh
>> Date:         Thu Jul 17 14:55:32 UTC 2014
>>
>> Modified Files:
>>       src/sys/sys: systm.h
>>
>> Log Message:
>> Expand null macros to `do {} while (0)', not to nothing.
>>
>>
>
> Not that I object, but out of curiosity, what is this good for, or, why is 
> this need/a good thing?
>
>> Index: src/sys/sys/systm.h
>> diff -u src/sys/sys/systm.h:1.263 src/sys/sys/systm.h:1.264
>> --- src/sys/sys/systm.h:1.263 Thu Apr  3 15:22:57 2014
>> +++ src/sys/sys/systm.h       Thu Jul 17 14:55:32 2014
>> @@ -1,4 +1,4 @@
>> -/*   $NetBSD: systm.h,v 1.263 2014/04/03 15:22:57 christos Exp $     */
>> +/*   $NetBSD: systm.h,v 1.264 2014/07/17 14:55:32 riastradh Exp $    */
>>
>> /*-
>>  * Copyright (c) 1982, 1988, 1991, 1993
>> @@ -527,7 +527,7 @@ void assert_sleepable(void);
>> #if defined(DEBUG)
>> #define       ASSERT_SLEEPABLE()      assert_sleepable()
>> #else /* defined(DEBUG) */
>> -#define      ASSERT_SLEEPABLE()      /* nothing */
>> +#define      ASSERT_SLEEPABLE()      do {} while (0)
>> #endif /* defined(DEBUG) */
>>
>> vaddr_t calc_cache_size(vsize_t , int, int);
>>

Wouldn't be '((void)0)' better?
Regards,
-- 
Lourival Vieira Neto