[Boost-users] Serialization: shared_ptr documentation

From: Malte Clasen (news_at_[hidden])
Date: 2004-11-26 00:28:58

Hi,

the serialization docs about shared_ptr state that you have to call 
void_cast_register to use shared_ptr:

----------
This indicates that we're not quite done. [...] In this case we need 
only the latter function so we can replace the base object serialization 
with:

// register the relationship between each derived class
// its polymorphic base
void_cast_register<
     boost::detail::sp_counted_base,
     boost::detail::sp_counted_base_impl<P, D>
 >();
----------
(http://boost.org/libs/serialization/doc/shared_ptr.html)

There are two issues with this:

a) The actual void_cast_register declaration has its parameters in the 
reverse order:

----------
template<class Derived, class Base>
inline BOOST_DLLEXPORT const void *  void_cast_register(
     const Derived * /* dnull = NULL */,
     const Base * /* bnull = NULL */
) BOOST_USED;
----------
(void_cast.hpp)

b) It doesn't seem to work either way, although there are different 
exceptions in both cases. The demo_shared_ptr.cpp doesn't even call it, 
instead the following is used:

----------
oa.register_type(
             static_cast<
                 boost::detail::sp_counted_base_impl<
                     B *, boost::checked_deleter<B>
                 > *
             >(NULL)
----------
(demo_shared_ptr.cpp)

This one actually works, the use counter is properly updated. So I guess 
the documentation is outdated, isn't it?

Malte