Subject: Re: [boost] [UUID] PODness Revisited
From: David Abrahams (dave_at_[hidden])
Date: 2008-12-26 02:35:55
on Thu Dec 25 2008, Adam Merz <adammerz-AT-hotmail.com> wrote:
> Vladimir Batov writes:
>> 1. Boost.MPI efficiency does not seem to rely on PODness. Rather it seem to
>> be due to serialization (or rather ability to bypass it).
> This isn't technically correct, I think; in MPI's case (though not
> Interprocess'), the type must be serializable regardless, but the ideal
> efficiency scenario comes from specializing both boost::mpi::is_mpi_datatype
> and boost::serialization::is_bitwise_serializable. Note that the documentation
> for these traits ( and , respectively) both specifically mention POD
> types -- this is no coincidence.
>  http://www.boost.org/doc/libs/1_37_0/doc/html/boost/mpi/is_mpi_datatype.html
>  http://www.boost.org/doc/libs/1_37_0/libs/serialization/doc/traits.html
Vladimir is technically correct in fact. It just so happens that PODs
are *guaranteed* to satisfy both the necessary qualifications. In
practice, many non-PODs will also do that, but of course that's not
guaranteed to be true, portably, for most non-POD types.
-- Dave Abrahams BoostPro Computing http://www.boostpro.com
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