Re: [Boost-users] [serialization] Implementation in mutliple DLLs

Subject: Re: [Boost-users] [serialization] Implementation in mutliple DLLs
From: Guy Prémont (guy.premont_at_[hidden])
Date: 2010-09-09 10:28:58

Thanks for the inputs.

I did get a bit farther, but I forgot to mention an important fact: i am
using my archive classes, based on the existing boost::archive classes.
Therefore, they also must be exported/imported. I think it is the main issue
that is preventing the linking of the DLLs, because of undefined symbols
notably boost::archive::detail::basic_oserializer and basic_iserializer.

I can see why, because defining an archive class uses a mix of template
classes and standard classes that need to be exported/imported. Some are
implemented in boost_serialization.dll which complicates the issue further.

Guy

> 
> Guy Premont wrote:
> > Hi,
> >
> > I've done research on the list and could not find any pointer about
> my
> > problem so here it is.
> >
> > I'm using windows, boost 1.40, and  vc9, i am not using polymorphic
> > archives, and i'm using member function serialization.
> >
> > In a big project, separated in different modules, I want to spread
> > serialization also into different DLLs. Typically, i have a base
> class
> > Base, implemented in Base.dll and the serialization is in
> > BasePersistence.dll. The serialization member functions are marked
> > with ddlexport or dllimport, explicit template instantiation is done
> > to force inclusion in the dll. So far everything is working.
> >
> > Now I have a class Derived, derived from Base, implemented in
> > Derived.dll. If i have only one serialization library that handle all
> > classes, it works fine, but I want the serialization to be split with
> > the same module as the implemention. So, I want the serialization of
> > class Derived to be in DerivedPersistence.dll. It compiles but fails
> > to link, There are a lot of undefined symbols, most are in
> > boost::serialization::archive namespace.
> >
> > Is there a special BOOST_DLL flag to use? It seems like the
> > DerivedPersistence.dll does not find in BasePersistence.dll the
> > functions it should find.
> >
> > Is it at all possible to spread the serialization code into multiple
> > dependent DLLs? Just having something to hint at a possible solution
> > would be a big help.
> 
> In recent versions of the library, the whole issue of spreading
> serialization implemenation across DLL s has recieved a lot of
> attention.
> 
> It's a stick subject.
> 
> First you should read the latest version of the documentation.
> Look at the latest explanation on EXPORT macros.
> 
> Second, Look at the demo's and tests in the latest package.
> These specifically include cases of having Derived in a separate
> DLL than the base class and it's its interface.  Examples of
> a "plug-in" are shows so that one could write his whole
> application around the base class interface and plugin
> a derived class implementation (including serialization) at
> some subsequent time - without rebuilding the main app!
> 
> There are still some pending issues though.  The library
> code has to ability to detect violations of ODR at runtime
> but this has been suppressed because too many applications
> have violations.  In the future this will be resurrected as
> an optional feature.
> 
> Robert Ramey
> 
> 
> 
> 
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