I am using Boost 1.32.0 with Borland C++ Builder 6 and attempting to
serialize an object via a pointer to a base class but I am getting a
runtime exception of "unregistered void cast".
Having read the page in the documentation on Runtime Casting, I thought
I should be able to use boost::serialization::void_cast_register(0,0); to associate the base and derived classes, but I can't
get it to work. If I use the alternate method (to serialize the base
class and provide a do-nothing serialize method in the base class) then
it works fine. Any ideas what's wrong?
The program below demonstrates the problem. Class A uses the serialize
base class method and that's ok while class B uses the
void_cast_register method and an exception is thrown when it's
serialized:
-----
#include <iostream>
#include
#include
#include
#include
#include
#if defined(_DEBUG)
# pragma link "libboost_serialization-bcb-mt-d-1_32.lib"
#else
# pragma link "libboost_serialization-bcb-mt-1_32.lib"
#endif
class Base_c
{
public:
virtual void SomeMethod() = 0;
private:
friend class boost::serialization::access;
template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{}
};
BOOST_IS_ABSTRACT(Base_c)
class A : public Base_c
{
public:
A() : m_Id("A"){};
void SomeMethod(){};
private:
friend class boost::serialization::access;
template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{
/* boost::serialization::void_cast_register(0,0); */
ar & boost::serialization::make_nvp("Base",
boost::serialization::base_object(*this));
ar & BOOST_SERIALIZATION_NVP(m_Id);
}
std::string const m_Id;
};
BOOST_CLASS_EXPORT(A);
class B : public Base_c
{
public:
B() : m_Id("B"){};
void SomeMethod(){};
private:
friend class boost::serialization::access;
template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{
boost::serialization::void_cast_register(0,0);
/* ar & boost::serialization::make_nvp("Base",
boost::serialization::base_object(*this)); */
ar & BOOST_SERIALIZATION_NVP(m_Id);
}
std::string const m_Id;
};
BOOST_CLASS_EXPORT(B)
main(int, char**)
{
boost::filesystem::ofstream
OfStream(boost::filesystem::path("D:\\Temp\\SerialisationText.xml",
boost::filesystem::native));
boost::archive::xml_oarchive Archive(OfStream);
try
{
Base_c *pBase, *pBase2;
pBase = new A();
pBase2 = new B();
Archive & boost::serialization::make_nvp("AByBasePointer", pBase);
std::cout << "Serialised A ok\n";
Archive & boost::serialization::make_nvp("BByBasePointer", pBase2);
std::cout << "Serialised B ok\n";
}
catch (std::exception& E)
{
std::cout << "Exception: " << E.what();
}
}
-----
The output is:
Serialised A ok
Exception: unregistered void cast
