Re: [Boost-users] Serializing derived class in dll

Subject: Re: [Boost-users] Serializing derived class in dll
From: Robert Ramey (ramey_at_[hidden])
Date: 2009-06-12 18:30:16

Shouldn't there be some "decl" statements in here?

There is a test in the package test_dll_exported...

Perhaps you might check to see that that test works with your setup.

I'm now in the process of adding tests for this functionality
for version 1.40 . Can't promise I'll make the deadline though.

Robert Ramey

Christian Bergstrand wrote:
> I am working on a programwith pluggable classes delivered in DLLs, so
> I have an virtual abstract base class in my EXE and both abstract and
> concrete classes in a hiearchy in my first DLL. I am trying ot
> serialize the derived class instances through a base class pointer. I
> am not able to get it to work after reading the samples in the 
> documentation and
> the most likely looking threads here.
>
> So I broke it down in to a sample EXE/DLL and can still not get it to
> work.
> I am using version 1_38 currently, also tried with 1_36_0
>
> I am getting the exeption on oserializer.hpp:374 where the comment
>            says // note:if this exception is thrown, be sure that
> derived pointer
>            // is either registered or exported.
>
> In my opinion I am exporting my derived class, but I am feeling that
> it is probably going into the wrong instance, since the export code is
> going into the DLL, but I can not find any other recomendation.
>
> So what am I missing ...
>
> ------------------------
> serializedll\base.h
> ------------------------
> #pragma once
>
> class Base
> {
> public:
>    virtual void f() = 0;
> private:
>    friend class boost::serialization::access;
>    template<class Archive>
>    void serialize(Archive & ar, const unsigned int version)
>    {
>    }
> };
> BOOST_SERIALIZATION_ASSUME_ABSTRACT( Base )
>
> ------------------------
> serializedll\serializedll.cpp, in the EXE
> ------------------------
> #include <tchar.h>
> #include <windows.h>
>
> #include <fstream>
>
> #include <boost/archive/text_oarchive.hpp>
> #include <boost/serialization/nvp.hpp>
>
> #include "base.h"
>
>
> int _tmain(int argc, _TCHAR* argv[])
> {
>    typedef Base * ( GetObjFun )();
>    GetObjFun * f = (GetObjFun*)GetProcAddress( LoadLibrary( TEXT(
> "plugin.dll" ) ), "getobj" );
>    Base * obj = f();
>
>    std::ofstream ofs( "c:\\test.xml" );
>    boost::archive::text_oarchive oa(ofs);
>
>    oa << obj;
>
>    return 0;
> }
>
>
> ------------------------
> plugin\plugin.cpp, in the DLL
> ------------------------
> #include <windows.h>
>
> #include <boost/serialization/export.hpp>
> #include <boost/archive/text_oarchive.hpp>
>
> #include "../serializedll/base.h"
>
> BOOL APIENTRY DllMain( HMODULE hModule, DWORD ul_reason_for_call,
> LPVOID lpReserved )
> {
>    return TRUE;
> }
>
> class Derived : public Base
> {
> public:
>    virtual void f()
>    {
>    }
> private:
>    friend class boost::serialization::access;
>    template<class Archive>
>    void serialize(Archive & ar, const unsigned int version)
>    {
>        ar & boost::serialization::base_object< Base >( *this );
>    }
> };
>
> BOOST_CLASS_EXPORT( Derived )
>
> Base * getobj()
> {
>    return new Derived();
> }