[Boost-users] [boost][serialization] How to implement serialization classes in two DLLs

From: jf332-3 (mviala.acticm_at_[hidden])
Date: 2006-01-29 05:21:50

Hi,

After few hour on the subject, I’m would like to have some explanations &
recommendations one the boost serialization library. To explain, my problem, you
will find hereafter a VC++ 7.1 project that demonstrates it. 

Problem Description 
We have involved in a large project with for example two DLLs libraries: LibA
and LibB. These libraries define & implement one class each other, let’s say
libA::A and libB::B. These two classes can be serialized through boost
serialization engine. 

The interfaces for the two classes are the same:

----------------------
struct LIBA_API A 
{
  std::vector<double> my_vector ;

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

  BOOST_SERIALIZATION_SPLIT_MEMBER()
};

  LIBA_API 
    void save(const libA::A* pObj, std::ostream& os) ;
  LIBA_API 
    void load(libA::A* &pObj, std::istream& is) ;
}; // Namespace libA
----------------------

The two free functions save() and load() are defined to be able to serialize the
class libA::A (respectively the class libB::B). 

When, we try to use these interfaces in an EXE application:

----------------------
#include <LibA/A.h>
#include <LibB/B.h>

#include <boost/filesystem/path.hpp>
#include <boost/filesystem/fstream.hpp>

#pragma comment(lib, "liba_d.lib")
#pragma comment(lib, "libb_d.lib")

int
main(int argc, char* argv[])
{
  libA::A a;
  libA::save(&a, boost::filesystem::ofstream("a.xml"));

  libB::B b;
  libB::save(&b, boost::filesystem::ofstream("b.xml")); // -> Assert in debug mode

  return 0;
}
----------------------

The figure hereafter describes the relationships between LibA, LibB and EXE.
                      ------------                         ------------
                      | LibA      |                        |  LibB    |
                      ------------                         ------------
                                   \                       /
                                    \                     /                    
                                  
                                        Exe Application

We have to face to an assert in debug mode generate by the file
boost::serialization::extended_type_info.cpp, line#71. This assert happens
during the instance serialization of class libB:B. 

Recently, there are some posts on this subject, but I would like to known how I
can deal with this assert? Is it possible to avoid it by a code organisation? 

To have a concrete answer, I have joined my complete VC++7.1 project. 

Thanks in advance for your help.

Development Platform
WindowsXP 
VC++ 7.1
Boost 1.33.1

Marc Viala
mailto:mviala_at_[hidden]