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

1 Feb 2006

      Hi,

I'm very sorry to post the message hereafter a second time, but I've not
received any reply, maybe I've missed it.

Any workaround or recommendations will be welcome because we are right
now surrounded in our software development. 

Thanks in advance.     

Marc VIALA

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, 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 
#include 

#include 
#include 

#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 application:
                      ------------
------------
                      |       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? Is it possible to comment this assert?

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@acticm.com mailto:mviala@acticm.com