[Boost-users] Serialization difficulties

From: Joseph Hosteny (jhosteny_at_[hidden])
Date: 2006-04-28 12:46:13

Hi all,

        I'm a relative newbie at using the serialization libraries, so  
please go easy on me, but I'm having some troubles which I can't seem  
to work out.

        I have a class hierarchy that looks something like this:

A -> B -> C -> D

        There is a corresponding header, and at least one source file, for  
each of the four classes.

        The base class, A, contains only methods, but is not a pure virtual  
class. Class B contains the first set of data members in the chain  
that must be serialized. Classes C and D contain some more methods  
and data. All stores/loads will be handled via pointers to instances  
of class D.

        Now, the header file for class B contains the following:

#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/serialization/access.hpp>
#include <boost/serialization/base_object.hpp>

        Classes B, C and D define the following as public:

friend class boost::serialization::access;
template<class Archive> void serialize(Archive &ar, const unsigned  
int version);

        The serialize methods for classes C and D call the base class  
implementations of these methods via:

ar & boost::serialization::base_object<base_class>(*this);

        Finally, the source files for classes B, C and D contain:

#include <boost/serialization/export.hpp>
BOOST_CLASS_EXPORT(class_name);

        It's not clear to me, though, that I should need the EXPORT macro  
since all loads/stores are done with the most derived class' pointers.

        However, when I run this code, I get an exception at  
oserialization.hpp line 394, which is of type  
archive_exception::unregistered type.

        I've looked through a lot of the documentation, but can't seem to  
find out what I'm doing wrong. I've also tried explicit calls to  
boost::serialization::void_cast_register<base_class, derived_class> 
(), but that didn't seem to work either.

        Since this is being retrofitted to a large design, I tried to  
distill what I was trying to do into a sample project with just empty  
classes with the same hierarchy and boot methods/macros. When I do  
this, everything seems to work fine.

        Does anyone have any suggestions on what I should look for that may  
be screwing things up for me? I can send the sample files I used, but  
since these work, I'm not sure if they will be of much help. Any  
pointers will be greatly appreciated!

Thanks,
Joe