I asked Jeremy Pack for permission to report his answers to my questions that I sent him through his personal website; here it is : Unfortunately, some of the C++11 stuff did not go the way I needed it to.
The linking guarantees it provides are not strong enough to provide for consistent shared library behavior across platforms. Many tasks that work just fine with certain compiler/platform combinations break horrifically on others. One example is being able to call the constructor in one shared library and the destructor in another shared library for an object, which only works on certain platforms.
This and other serious issues can cause bizarre bugs for users whose code looks perfectly natural. Resolving these issues would result in a very complicated and inelegant API, and a complete rewrite of the library. I won't have time to do any of this work for quite some time, as I am currently a full-time software engineer and part-time student. I'm sorry for the bad news!
Jeremy
I wonder if even with those problems it would be possible to write a cross-platform library to do only the shared-library loading/unloading and function call. A minimal subset of the current boost.extension. Joël Lamotte