Re: [Boost-users] Serialization: Problem with registering derivedclasses

Hello,

I took your code and fixed it up to that below and it compile and tests fine.

Note the usage of BOOST_SERIALIZATION_BASE_OBJECT_NVP below which is key. This is explained in the documentation.

thanks a lot for the answer. Now it works correctly, I still "dare" to give a suggestion and ask help again: 1) In the documentation I think that the relevant information about how to serialize properly a derived polymorphic class should stay also in "Pointers to Objects of Derived Classes -> Registration". In that section is not mentioned boost::serialization::base_object nor BOOST_SERIALIZATION_BASE_OBJECT_NVP, and I think it would be helpful to add an explanation in there: in fact the provided example (class base ... class derived_one ... derived_two) does not work out of the box. I think that to the above mentioned section should be added a reference (or directly the content) of the section Serializable Concept->Pointers->Pointers of Derived Objects->Runtime Casting, which explicitly says to call boost::serialization::base_object<base>(*this), so that the relationship between a "base/derived pair is added to the table", and make things working :) 2) Since I do not like to serialize the base object, I do not want to call boost::serialization::base_object in the derived serializing method, but instead I wish to just explicitly register base/derived relationship with: boost::serialization::void_cast_register(); as the section Runtime Casting tells the reader. But it does not work (compilation fails), I still need to add two NULLs parameters to that function, such as: boost::serialization::void_cast_register(NULL, NULL); so the code of derived::base::serialize method of the example should be corrected. By the way in file void_cast_fwd.hpp for the method void_caster::void_cast_register the default arguments to NULL appear to be commented out, I wonder why. 3) What is preferred statement between oa.register_type (static_cast (NULL)); and oa.register_type<Serializable> (); ? I tested that either works fine with VC8, and I guess they work fine with gcc4 too, but i wonder why I see in the examples of Boost the former used in place of the latter form which is commented out. Best regards, Luca Cappa