[boost] Re: [serialization] automatic linking and intrusiveserialization support

From: Robert Ramey (ramey_at_[hidden])
Date: 2005-02-08 18:20:41

I've recently checked in changes to the serialization library to support

a) DLLS boost_serialization.dll and boost_wserialization.dll.  These are
counterparts to libboost* respectively.
b) autolink is now supported
c) there is a new member function for loading archives -
reset_object_address to deal with the issues raised by loading collections.

The usage of autolink has created a problem with one of the examples
demo_portable_archive which derives from a class whose implementation is
implemented in the DLL.  MS compilers this needs the keyword
__declspec(dllexport) and since some of code is templated on the most
derived class - there's a problem with templated code using
__declspec(dllexport) while the library code with different template
parameters does not.  My head started to hurt when I thought about it so I
just left it as a failing test for VC compilers.

Now to your question.

fJOAQUIN LOPEZ MU?Z wrote:
> Suppose I'm the user of a class called foo which supports
> serialization through intrusive methods. So, foo.h will look
> like:
>
> // foo.h
>
> #include <boost/serialization/access.hpp>
>
> // other, non serialization-related includes
>
> class foo
> {
>   ...
> };
>
> Now, a programmer uses foo, but does not take advantage of
> its serialization capabilities.
>
> // user.cpp
> #include <foo.h>
>
> // use foo
>
> and a second programmer uses foo *and* serializes it.
>
> //user2.cpp
> #include <foo.h>
> #include <boost/archive/text_oarchive.hpp>
>
> // use foo and its serialization capabilities.
>
>
> So far so good. Boost 1.33 release of Boost.Serialization,
> if I'm not wrong, will include automatic linking, and here comes
> the problem: when doing the upgrade to 1.33, user2 will be
> delighted that he'll no longer need to do the linking stuff by
> himself;

> but user1 will get mysterious "not found" linking errors,
> or worse yet, he'll have Boost.Serialization automagically
> bundled into his final executable, when he never explictly
> dealed with this lib in the program!

I don't believe this is the case. Templated code is not emitted unless
explictly invoked.  If user2 never serializes anything the then the member
serialization template won't be expanded.  This view is supported by the
fact that if serialization isn't used - then no *_iarchive.hpp file is
included so the template argument Archive has no known value so its
impossible for the compiler emit the code.

Robert Ramey