Messages in this thread | | | Date | Wed, 27 Jun 2007 17:40:46 +0200 | From | Adrian Bunk <> | Subject | Re: Linux Kernel include files |
| |
On Tue, Jun 26, 2007 at 09:32:39PM -0400, Kyle Moffett wrote: > On Jun 22, 2007, at 11:00:38, Adrian Bunk wrote: >> It would certainly help if Joerg would tell what exactly breaks, but I >> spot one likely problem in include/asm-i386/types.h: >> >> #if defined(__GNUC__) && !defined(__STRICT_ANSI__) >> typedef __signed__ long long __s64; >> typedef unsigned long long __u64; >> #endif >> >> It might make sense to remove the #if and simply require that a C compiler >> under Linux must know about the C99 "long long"? > > Gah, this particular topic and a few other similar header-compatibility > ones show up once a month on LKML; I should probably just make a patch to > fix all the types.h files and be done with it. The proper solution is > this: > > # if __STDC_VERSION__ >= 19901L > typedef signed long long __s64; > typedef unsigned long long __u64; > # elif defined(__GNUC__) > __extension__ typedef signed long long __s64; > __extension__ typedef unsigned long long __u64; > # else > # error "Your compiler doesn't support long long (IOW: It sucks). Please > get a new one"
This part is wrong.
gcc supported "long long" before C99 existed. And Joerg said the Sun cc supported "long long" before gcc did.
> # endif > > That way if you have any kind of vaguely-long-long-compatible compiler then > it will work, and otherwise you'll get a nice useful error message.
No, consider a pre-C99 gcc version that supports "long long".
> It > also makes sure that GCC doesn't spew warnings/errors when in c89-pedantic > mode. The "__extension__" keyword is designed for use in implementation > header files which want to use GCC-isms unconditionally.
That's a good point I missed.
What about:
#if defined(__GNUC__) && __STDC_VERSION__ < 19901L __extension__ typedef signed long long __s64; __extension__ typedef unsigned long long __u64; #else typedef signed long long __s64; typedef unsigned long long __u64; #endif
> Cheers, > Kyle Moffett
cu Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |