Re: Data representation formats

ts@datcon.co.uk (Tony Sowter) writes:


> It seems to me that there must be a way of storing information about the
> packing used by the hardware/compiler combination in a handful of bytes
> (RPC systems must have something like this).






Neither ONC nor DCE deal with structure packing at all. In both cases
marshalling/unmarshalling of a structure is done 1 field at a time,
never in block.


Trying to describe structure packing is not obvious. Some compilers
reorder fields, some will align char arrays with an even number of
elements, but not char arrays with an odd number of elements (I have
one specific compiler in mind), etc. Dealing with all the possible
packings across many platform would probably require more logic than
one would care to have, at least as much as each compiler uses for its
optimizations.


I guess one could restrict the support to widely accepted ABI specs
for each platform. Still if the number of supported platforms is
large you are going to deal with quite a lot of logic needed at least
within each server process.


Max P. Grasso
max@osf.org
(617)621-8746
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