[systemd-devel] [PATCH] architecture: fix building for big-endian PowerPC with gcc

[Lennart Poettering]

On Fri, 11.07.14 15:04, Michael Olbrich (m.olbrich at pengutronix.de) wrote:

> gcc does not define WORDS_BIGENDIAN for big-endian PowerPC. It defines
> __BIG_ENDIAN__ instead. So also check for __BIG_ENDIAN__ to determine if
> the system is big-endian.

Hmm, the sources currently use three different ways to detect endianess:

1) WORDS_BIGENDIAN (which appears to be an autoconf thing actually,
   enabled via AC_C_BIGENDIAN, which we never call currently)
2) __BTYE_ORDER == __BIG_ENDIAN which appears to be be defined in
   endian.h always by glibc
3) __BIG_ENDIAN__ appears to be quite common too? gcc thing?

Also this:

http://sourceforge.net/p/predef/wiki/Endianness/

We should probably stick to one of these things. Probably #2 or #3...

I can't find any normative documentation about these things. Given that
the #2 is at least unconditional part of glibc, I'd say to convert
everything to that. Would that work for you on ppc-be too?

Lennart

-- 
Lennart Poettering, Red Hat