Messages in this thread | | | Date | Tue, 19 Aug 2008 23:06:04 +0200 | From | "Frans Meulenbroeks" <> | Subject | Re: inclusion of <endian.h> in a kernel header? ok or not? |
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2008/8/19 Adrian Bunk <bunk@kernel.org>: > On Tue, Aug 19, 2008 at 09:16:56PM +0200, Frans Meulenbroeks wrote: >> Is it ok to #include <endian.h> in a kernel header file. >> This is done in linux/patchkey.h and linux/soundcard.h but other >> places seem to prefer <asm/byteorder.h> >>... > > Look at the two files you mention - they only do it in userspace. > > And considering that these only users in the kernel are in the OSS code > it's most likely not the best solution.
Agree. But as I want to do it right I'd like to know what the best way is. would that be including <asm/byteorder.h> and then have code with #ifdef __LITTLE_ENDIAN #else #endif be the preferred solution?
(I don't want to use the conversion functions just want to get the leftmost short from an uint32_t)
With gcc 4.1.3 (which is the default on my ubuntu 7.10 dev system) a typecast like a_short = *(unsigned short volatile *)&a_long; which would do the trick gives faulty code with -O2 or up.
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