Re: CVS commit: src/sys/sys

[Marc Balmer <marc%msys.ch@localhost>]

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);
>