Serialization v1.33.0 and Serializing derived classes through base class
I'm having a newbie issue with serialization on a derived class with a virtual function. I'm using the 1.33.0 build on VS 7.1. I've shrunken my code to a micro-version of what I tried to do. Here I have two classes, A and B, where B is a subclass of A. They share a virtual function (ie B overrides dumpFunc in A). I've registered B with BOOST_CLASS_EXPORT(B). I've turned on RTTI in VS 7.1 (/GR or whatever). Still, I get a run time assert error in the boost library telling me that the derived/base relationship wasn't registered. Here's the code. I'll try to spell out the error below. #include <string> #include <fstream> #include <boost/archive/tmpdir.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/serialization/export.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/utility.hpp> #include <boost/serialization/vector.hpp> class A; class B; class A { friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & m_className; }; std::string m_className; public: A() { m_className = "ClassA\n"; }; virtual void dumpFunc() {}; }; class B : public A { friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & m_classNameB; }; std::string m_classNameB; public: B() { m_classNameB = "ClassB\n"; }; virtual void dumpFunc() {}; }; BOOST_CLASS_EXPORT(B) void main() { std::vector<A *> vecA; B *b=new B(); vecA.push_back(b); std::ofstream ofs("saveFile.sav"); boost::archive::text_oarchive oa(ofs); oa & vecA; delete b; } The following is a stack trace of where it hits the assert. The key thing to note is that save_pointer_type bails out after deciding that class B was not registered. I'm hoping that this is a rookie error but I just can't see it. Thanks. kernel32.dll!7c81eb33() kernel32.dll!7c81eb33() junkProject.exe!_CxxThrowException(void * pExceptionObject=0x0012de10, const _s__ThrowInfo * pThrowInfo=0x004f8400) + 0x39 C++
junkProject.exe!boost::throw_exception<boost::archive::archive_exception>(const boost::archive::archive_exception & e={...}) Line 40 C++ junkProject.exe!boost::archive::detail::save_pointer_type<boost::archive::text_oarchive,A *>::polymorphic<A>::save(boost::archive::text_oarchive & ar={...}, const A & t={...}, const boost::archive::detail::basic_pointer_oserializer * bpos_ptr=0x00504544) Line 410 + 0x34 C++ junkProject.exe!boost::archive::detail::save_pointer_type<boost::archive::text_oarchive,A *>::save<A>(boost::archive::text_oarchive & ar={...}, const A & t={...}, const boost::archive::detail::basic_pointer_oserializer * bpos_ptr=0x00504544) Line 438 + 0x11 C++ junkProject.exe!boost::archive::detail::save_pointer_type<boost::archive::text_oarchive,A *>::invoke(boost::archive::text_oarchive & ar={...}, A * const t=0x00323bb0) Line 466 + 0x11 C++ junkProject.exe!boost::archive::save<boost::archive::text_oarchive,A *>(boost::archive::text_oarchive & ar={...}, A * const & t=0x00323bb0) Line 535 + 0xf C++ junkProject.exe!boost::archive::basic_text_oarchive<boost::archive::text_oarchive>::save_override<A * const>() Line 78 + 0x15 C++ junkProject.exe!boost::archive::detail::interface_oarchive<boost::archive::text_oarchive>::operator<<<A * const>() Line 86 C++ junkProject.exe!boost::serialization::nvp<A * const>::save<boost::archive::text_oarchive>() Line 78 C++ junkProject.exe!boost::serialization::access::member_save<boost::archive::text_oarchive,boost::serialization::nvp<A * const> const >() Line 94 C++ junkProject.exe!boost::serialization::detail::member_saver<boost::archive::text_oarchive,boost::serialization::nvp<A * const> >::invoke(boost::archive::text_oarchive & ar={...}, const boost::serialization::nvp<A * const> & t={...}, const unsigned int file_version=0) Line 43 + 0x11 C++ junkProject.exe!boost::serialization::split_member<boost::archive::text_oarchive,boost::serialization::nvp<A * const> >(boost::archive::text_oarchive & ar={...}, boost::serialization::nvp<A * const> & t={...}, const unsigned int file_version=0) Line 69 + 0x11 C++ junkProject.exe!boost::serialization::nvp<A * const>::serialize<boost::archive::text_oarchive>() Line 87 + 0x34 C++ junkProject.exe!boost::serialization::access::serialize<boost::archive::text_oarchive,boost::serialization::nvp<A * const> >() Line 110 C++ junkProject.exe!boost::serialization::serialize<boost::archive::text_oarchive,boost::serialization::nvp<A * const> >(boost::archive::text_oarchive & ar={...}, boost::serialization::nvp<A * const> & t={...}, const unsigned int file_version=0) Line 81 + 0x11 C++ junkProject.exe!boost::serialization::serialize_adl<boost::archive::text_oarchive,boost::serialization::nvp<A * const> >(boost::archive::text_oarchive & ar={...}, boost::serialization::nvp<A * const> & t={...}, const unsigned int file_version=0) Line 140 + 0x18 C++ junkProject.exe!boost::archive::detail::save_non_pointer_type<boost::archive::text_oarchive,boost::serialization::nvp<A * const> >::save_only::invoke(boost::archive::text_oarchive & ar={...}, const boost::serialization::nvp<A * const> & t={...}) Line 256 + 0xf C++ junkProject.exe!boost::archive::detail::save_non_pointer_type<boost::archive::text_oarchive,boost::serialization::nvp<A * const> >::invoke(boost::archive::text_oarchive & ar={...}, const boost::serialization::nvp<A * const> & t={...}) Line 321 + 0xd C++ junkProject.exe!boost::archive::save<boost::archive::text_oarchive,boost::serialization::nvp<A * const> >(boost::archive::text_oarchive & ar={...}, const boost::serialization::nvp<A * const> & t={...}) Line 535 + 0xd C++ junkProject.exe!boost::archive::basic_text_oarchive<boost::archive::text_oarchive>::save_override<boost::serialization::nvp<A * const> const >() Line 78 + 0x15 C++ junkProject.exe!boost::archive::detail::interface_oarchive<boost::archive::text_oarchive>::operator<<<boost::serialization::nvp<A * const> const >() Line 86 C++ junkProject.exe!boost::serialization::stl::save_collection<boost::archive::text_oarchive,std::vector<A *,std::allocator<A *> > >(boost::archive::text_oarchive & ar={...}, const std::vector<A *,std::allocator<A *> > & s={...}) Line 44 C++ junkProject.exe!boost::serialization::save<boost::archive::text_oarchive,A *,std::allocator<A *> >(boost::archive::text_oarchive & ar={...}, const std::vector<A *,std::allocator<A *> > & t={...}, const unsigned int __formal=0) Line 49 + 0xd C++ junkProject.exe!boost::serialization::free_saver<boost::archive::text_oarchive,std::vector<A *,std::allocator<A *> > >::invoke(boost::archive::text_oarchive & ar={...}, const std::vector<A *,std::allocator<A *> > & t={...}, const unsigned int file_version=0) Line 45 + 0x18 C++ junkProject.exe!boost::serialization::split_free<boost::archive::text_oarchive,std::vector<A *,std::allocator<A *> > >(boost::archive::text_oarchive & ar={...}, std::vector<A *,std::allocator<A *> > & t={...}, const unsigned int file_version=0) Line 74 + 0x11 C++ junkProject.exe!boost::serialization::serialize<boost::archive::text_oarchive,A *,std::allocator<A *> >(boost::archive::text_oarchive & ar={...}, std::vector<A *,std::allocator<A *> > & t={...}, const unsigned int file_version=0) Line 76 + 0x11 C++ junkProject.exe!boost::serialization::serialize_adl<boost::archive::text_oarchive,std::vector<A *,std::allocator<A *> > >(boost::archive::text_oarchive & ar={...}, std::vector<A *,std::allocator<A *> > & t={...}, const unsigned int file_version=0) Line 140 + 0x18 C++ junkProject.exe!boost::archive::detail::oserializer<boost::archive::text_oarchive,std::vector<A *,std::allocator<A *> >
::save_object_data(boost::archive::detail::basic_oarchive & ar={...}, const void * x=0x0012febc) Line 151 + 0x2b C++
junkProject.exe!boost::archive::detail::basic_oarchive_impl::save_object(boost::archive::detail::basic_oarchive & ar={...}, const void * t=0x0012febc, const boost::archive::detail::basic_oserializer & bos={...}) Line 271 C++ junkProject.exe!boost::archive::detail::basic_oarchive::save_object(const void * x=0x0012febc, const boost::archive::detail::basic_oserializer & bos={...}) Line 412 C++ junkProject.exe!boost::archive::detail::save_non_pointer_type<boost::archive::text_oarchive,std::vector<A *,std::allocator<A *> >
::save_standard::invoke(boost::archive::text_oarchive & ar={...}, const std::vector<A *,std::allocator<A *> > & t={...}) Line 264 C++
junkProject.exe!boost::archive::detail::save_non_pointer_type<boost::archive::text_oarchive,std::vector<A *,std::allocator<A *> > >::invoke(boost::archive::text_oarchive & ar={...}, const std::vector<A *,std::allocator<A *> > & t={...}) Line 321 + 0xd C++ junkProject.exe!boost::archive::save<boost::archive::text_oarchive,std::vector<A *,std::allocator<A *> > >(boost::archive::text_oarchive & ar={...}, const std::vector<A *,std::allocator<A *> > & t={...}) Line 535 + 0xd C++ junkProject.exe!boost::archive::basic_text_oarchive<boost::archive::text_oarchive>::save_override<std::vector<A *,std::allocator<A *> > const >() Line 78 + 0x15 C++ junkProject.exe!boost::archive::detail::interface_oarchive<boost::archive::text_oarchive>::operator<<<std::vector<A *,std::allocator<A *> > const >() Line 86 C++ junkProject.exe!boost::archive::detail::interface_oarchive<boost::archive::text_oarchive>::operator&<std::vector<A *,std::allocator<A *> > >(std::vector<A *,std::allocator<A *> > & t={...}) Line 97 C++ junkProject.exe!main() Line 65 C++ junkProject.exe!mainCRTStartup() Line 259 + 0x19 C kernel32.dll!7c816d4f() ntdll.dll!7c915b4f() kernel32.dll!7c8399f3() - David
David Parks wrote:
I'm having a newbie issue with serialization on a derived class with a virtual function. I'm using the 1.33.0 build on VS 7.1. I've shrunken my code to a micro-version of what I tried to do. Here I have two classes, A and B, where B is a subclass of A. They share a virtual function (ie B overrides dumpFunc in A). I've registered B with BOOST_CLASS_EXPORT(B). I've turned on RTTI in VS 7.1 (/GR or whatever). Still, I get a run time assert error in the boost library telling me that the derived/base relationship wasn't registered. Here's the code. I'll try to spell out the error below.
class B : public A { friend class boost::serialization::access;
template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & m_classNameB; }; std::string m_classNameB; public: B() { ar & boost::serialization::base_object<A>(*this); //<<<<< inssert this ! m_classNameB = "ClassB\n"; }; virtual void dumpFunc() {}; };
This little detail isn't that obvious - even though it is described in the manual. Normally, derived classes need to call serialization of their parents. This fact is leveraged to "register" the relationship between a derived class and its parent which is used to serialization a derived class from a base class pointer. If this "base_object" isn't used, this relationship has to be made explicitly with "void_cast_register" from and even more obscure lower level. I made this change and verified that your program compiles and runs as you would hope. Robert Ramey
On 12/3/05 10:56 PM, "David Parks" <davidp@cs.berkeley.edu> wrote:
I'm having a newbie issue with serialization on a derived class with a virtual function. I'm using the 1.33.0 build on VS 7.1. I've shrunken my code to a micro-version of what I tried to do. Here I have two classes, A and B, where B is a subclass of A. They share a virtual function (ie B overrides dumpFunc in A). I've registered B with BOOST_CLASS_EXPORT(B). I've turned on RTTI in VS 7.1 (/GR or whatever). Still, I get a run time assert error in the boost library telling me that the derived/base relationship wasn't registered. Here's the code. I'll try to spell out the error below.
Why don't you follow the error's advice and register the derived/base relationship? The registration is not automatic.
#include <string> #include <fstream>
#include <boost/archive/tmpdir.hpp>
#include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/serialization/export.hpp> #include <boost/serialization/base_object.hpp>
You already included the necessary header, but you don't exploit it.
#include <boost/serialization/utility.hpp> #include <boost/serialization/vector.hpp>
class A; class B;
class A { friend class boost::serialization::access;
template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & m_className; }; std::string m_className; public: A() { m_className = "ClassA\n"; }; virtual void dumpFunc() {}; };
class B : public A { friend class boost::serialization::access;
template<class Archive> void serialize(Archive & ar, const unsigned int version) {
// Add this line to acknowledge base classes ar & boost::serialization::base_object<A>(*this);
ar & m_classNameB; }; std::string m_classNameB; public: B() { m_classNameB = "ClassB\n"; }; virtual void dumpFunc() {}; };
BOOST_CLASS_EXPORT(B)
void main() { std::vector<A *> vecA; B *b=new B(); vecA.push_back(b);
std::ofstream ofs("saveFile.sav"); boost::archive::text_oarchive oa(ofs); oa & vecA;
delete b; }
[TRUNCATE stack trace] -- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT hotmail DOT com
participants (2)
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Daryle Walker -
David Parks -
Robert Ramey