Why must butfields sum to a multiple of a byte?

[Andrej Mitrovic]

On 7/30/12, Ali Çehreli <acehreli at yahoo.com> wrote:
> It is inherently unportable because unlike D, bitfields in C and C++
> give too much freedom to the compiler. The compiler can move the fields
> around at will.

I really need to figure out a reliable way to extract this
information, at least for the target platform a library is compiled
on. gccxml gives some information which seems to be somewhat reliable
but according to the authors it's more of a guess than accurate info
(2nd paragraph):
http://www.gccxml.org/pipermail/gccxml/2012-February/001483.html

Still this isn't too shabby, there could be configuration options
where the user could set pack/bitsize/compiler options and similar
stuff which would make a codegenerator more reliable.