Re: [Boost-users] Serialization of template classes via base

From: Andreas Huber (ahd6974-spamgroupstrap_at_[hidden])
Date: 2005-09-08 10:47:59

Robert Ramey <ramey <at> rrsd.com> writes:
> Hmm - I the referenced email referred to shared_ptr.  Your case is covered 
> in the documenation.  Reference/Serializable/Pointers.

I think it is not. AFAICT what Bruno needs, is a way to *automatically* 
register all instantiations of a given template. As I have recently discovered 
I would have the same need when I want to add serialization to 
boost::statechart::state_machine<>.

>From the documentation it seems that what the serialization library currently 
supports is a way to register a type at *namespace* scope. That is, if I have 
a template ...

class A {};

template< class T >
class B
{
};

... I need to *manually* register all instantiations of B, e.g. as follows:

BOOST_CLASS_EXPORT_GUID( B< int > );
BOOST_CLASS_EXPORT_GUID( B< char > );
BOOST_CLASS_EXPORT_GUID( B< double > );
BOOST_CLASS_EXPORT_GUID( B< float > );

For a library containing B's definition, sometimes you can get away with 
requiring users to manually register all instantiations but often even the 
users cannot know all instantiations because B is an implementation detail of 
the library.

IIRC, registration within load/save (with register_type<>) is not an option, 
as that would be too late.

-- 
Andreas Huber 
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