Definition of _ALIGNBYTES

Marcel Moolenaar marcel at xcllnt.net
Sat Jul 29 20:10:30 UTC 2006


All,

In /usr/include/sys/param.h (or src/sys/powerpc/include/param.h),
_ALIGNBYTES is defined as (sizeof(int) - 1), or 3. It is supposed
to represent the mask used by ALIGN() to yield an alignment
suitable for all types. The alignment of the double, long long,
and long double types is 8, which would imply that _ALIGNBYTES
should be 7. All platforms, except i386, have this "right".

I don't know how vital this definition is, but I do know that
increasing it yields an ABI breakage (I noticed that ssh(1)
stopped working). The ABI breakage is not severe enough that
you cannot increase and decrease it without being able to do a
buildworld.

My question: should we bump it up while powerpc is still tier 2?

-- 
  Marcel Moolenaar         USPA: A-39004          marcel at xcllnt.net




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