>> #define WORDS_BIGENDIAN 1
>Did waf's endian-ness test not detect this properly?
waf's detection worked fine.
The above #define is from config.h on a PowerPC indicating what it did.
---------
> ISTR years ago seeing some C magic, where in a compile time declaration, one
> packs bytes into a struct union with an integer, and then at runtime looks
> at the integer value to determine the endianess on the fly. Downside: it has
> to be tested at runtime, which means the compile time optimizer is less
> likely to remove the unused code paths.
I've seen that sort of code. It wouldn't take me long to make something
similar.
> Is it the case that the C standard or the POSIX standard do not define a
> standard #define that tells the current endianess? That seems like just the
> sort of thing that the standard should do...
Fedora has a /usr/include/endian.h
I don't know if that's part of POSIX. Our code just includes it, no #ifdefs,
so I assume it is.
waf has a builtin.
if ctx.check_endianness() == "big":
ctx.define("WORDS_BIGENDIAN", 1)
-----------
There are 2 places in our code that know about endianness.
Several refclocks check WORDS_BIGENDIAN and do their own thing. It's used
for things like binary ints/floats sent over a serial port.
The packet format on the internet is big endian. There is code that swaps
when necessary in ntpd/ntp_proto.c via libntp/ntp_endian.c We could probably
clean up both areas by using endian.h
Eric: looks like an item for your list.
--
These are my opinions. I hate spam.
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