Two things are getting mixed up here.

 

a) The first is not using RTTI.  You've used the test as an example and this seems fine to me.

b) You want to serialize a polymorphic derived class through a pointer to it's base class.  This

is OK too, but requires special care.  The problem is that  C++ compile/link will generally not

include code which is not specifically referred to.  This occurs when compiling (optimizing out

dead code) and linking - skipping modules not referred to.

 

To deal with the second, you have "trick" the compiler/linker to not discard your code.  There

are a couple of ways to do this.

 

a) Somewhere in the main module, refer to the derived type in the library.  An easy way to

do this is to just create one more function in your code which refers to the code in the library.

Well, its not that easy because the C++ optimiser will usually throw away the whole call

if the result isn't used. You can use the "force_include.hpp" to keep this from happening.

b) You can re-package your library as a DLL.  DLLS are different in that the whole DLL

is imported when the application starts up - not just the functions actually referred to.

The "registers" all the "EXPORT"ed functions and things would as advertised.

 

Sorry it has to be this way.  The whole idea of using a library is to automatically

include only that code which the linker detects is actually called.  Loading through

a base class pointer explicitly hides this fact so one has to make special effort

of some sort.  The only other alternative would be to have the linker import ALL the

code in the library which would defeat the reason for having a library in the first place.