Re: [Boost-users] [serialization] export.hpp changes from 1.37 to 1.38

Subject: Re: [Boost-users] [serialization] export.hpp changes from 1.37 to 1.38
From: Chard (boost_at_[hidden])
Date: 2009-02-13 19:06:06

Oops, ignore this here, reposted to the dev group, where it was intended..

"Chard" <boost_at_hazlewoods.eu> wrote in message 
news:gn51a8$j87$1_at_ger.gmane.org...
> The BOOST_CLASS_EXPORT.. macros have been moved into a detail namespace
> (1.38) from a (public) anonymous namespace (1.37).
>
> I'm guessing that the reasoning for this was in order to avoid many
> definitions of the class singletons.  However, this appears to have 
> enforced
> that all of the guids (for all archive types) now have to reside in a 
> single
> compilation unit.
>
> The attached code illustrates the limitation; this compiles under 1.37 but
> results in duplicate symbol definitions in 1.38 (with MSVC7.1).  It worked
> with 1.37 because the anonymous namespace ensured no symbol clashes, but 
> now
> the symbols are all in the same namespace.
>
> The example shows a case where two archive types (xml and binary) might be
> in use.  The obvious solution to this (simple) case would be to just use a
> single compilation unit, which brings in the guids for both binary and 
> xml.
> However, turning a blind eye to the 'untidiness', this fix does not help
> with the project we're working on.
>
> In our project, there is not just a simple type being serialized; there 
> are
> a lot more classes and a bit of mpl thrown in.  This actually resulted in
> breaching the COFF symbol limit (approx. 65k) with MSVC7.1, so we were
> forced to split the serialization.  In fact, we had to split both the save
> and load parts of the binary serialization.
>
> Our current workaround is to use the archive.register_type<...> method, 
> and
> ignore the export macros, but this does mean ensuring all types are 
> covered
> (as described in the documentation).
>
>

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