Messages in this thread | | | Subject | Re: [PATCH] [RFC] #define __BYTE_ORDER | From | Joakim Tjernlund <> | Date | Wed, 24 Mar 2010 22:45:53 +0100 |
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geert.uytterhoeven@gmail.com wrote on 2010/03/24 19:37:36: > > On Wed, Mar 24, 2010 at 19:21, Andrew Morton <akpm@linux-foundation.org> wrote: > > On Wed, 17 Mar 2010 19:10:55 +0100 > > Joakim Tjernlund <Joakim.Tjernlund@transmode.se> wrote: > > > >> Linux does not define __BYTE_ORDER in its endian header files > >> which makes some header files bend backwards to get at the > >> current endian. Lets #define __BYTE_ORDER in big_endian.h/litte_endian.h > >> to make it easier for header files that are used in user space too. > > > > I don't get it. Why not nuke __BYTE_ORDER altogether and do `#ifdef > > __LITTLE_ENDIAN' and `#ifdef __BIG_ENDIAN' everywhere? > > Because in userspace the convention is that > 1. _both_ __LITTLE_ENDIAN and __BIG_ENDIAN are defined, > 2. you have to test for e.g. __BYTE_ORDER == __BIG_ENDIAN.
Precisely, I see that i forgot to mention that in the commit msg.
It is actually worse that that, gcc will only define one of __LITTLE_ENDIAN/__BIG_ENDIAN so you might be tricked that using just the __LITTLE_ENDIAN/__BIG_ENDIAN defines works. Then you add some include file such as stdlib.h and it all breaks because now both __LITTLE_ENDIAN and __BIG_ENDIAN are defined.
Jocke
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