__restrict__ vs __restrict ?
Tim Kientzle
kientzle at acm.org
Fri Jan 16 20:03:08 PST 2004
Ruslan Ermilov wrote:
> On Fri, Jan 16, 2004 at 05:23:01PM -0800, Tim Kientzle wrote:
>
>>Question: Does anyone know the difference between
>>__restrict and __restrict__?
>
> __restrict__ is the gcc(1)-only feature.
> __restrict is defined in <sys/cdefs.h>, it's the FreeBSD feature.
A-ha! That's the part I had missed. After a few experiments
with gcc -dM -E, I've convinced myself that this is just another
GCC bug. Basically, -std=c99 -ansi seems to be a very bad compination,
as -std=c99 defines __STDC_VERSION__ to be 199901L and -ansi then
turns off compiler support for c99 features. Ugh.
>>Should we be using the latter in our system headers?
>
> No, we should be using the __restrict as coded. But I wonder why
> we can't just use "restrict"...
Because that would really mess up any user program that used
'restrict' as a variable or function name. I think the
current approach is the best.
Thanks for the clarification. I'll go crawl back under
my nice, comfortable rock now.
Tim
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