Re: User level Macros for Endianess

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"iweiny" == iweiny  [off-list ref] writes:

iweiny> What Macros should I be using to key off of for this?  I have
iweiny> looked through /usr/include/endian.h and
iweiny> /usr/include/bits/endian.h.  BYTE_ORDER (without the leading
iweiny> underscores) is only defined if __USE_BSD is defined.  BOTH
iweiny> __BIG_ENDIAN and __LITTLE_ENDIAN are defined as are BIG_ENDIAN
iweiny> and LITTLE_ENDIAN.  I'm so confused?

#include <asm/byteorder.h>

then use __le32_to_cpu and friends (see
/usr/include/linux/byteorder/generic.h)

I'm not sure if that's the Proper Way(TM) to do it from user land
though.

Jesper

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On 12 Jan 2000, Jesper Skov wrote:

#include <asm/byteorder.h>

then use __le32_to_cpu and friends (see
/usr/include/linux/byteorder/generic.h)

I'm not sure if that's the Proper Way(TM) to do it from user land
though.

No, it's very different between application and kernel code (unfortunately
since this forced me to write 2 very different vme.h include files for VME
systems, it's not only a simple cp). Under Linux, asm/byteorder.h is the
right way to get the correct macros, and either LITTLE_ENDIAN or
BIG_ENDIAN is defined.

From userland both are defined and then BYTE_ORDER is set to one of these

(strange architecture might even have a byte order which is neither like
the PDP) so the check is #if __BYTE_ORDER==__BIG_ENDIAN ...

	Gabriel.


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