Thanks for your reply. I have considered another option that might be easier for us if it works: One of the options described in the documentation about compiling the unit test framework is "Including sources directly into test module project". This would normally lead to the same problems as the "include" option, however, we could include the Boost.Test sources into a separate shared library that we build using our own build system. Both our dynamically loaded library and our main application would link against this shared library to make sure the Boost.Test symbols are defined exactly once. The benefit would be that we could use our own build system instead of treating Boost.Test as an external library. This would make things a lot easier for us because we have to support many platforms. Do you think this would work? Or are there some other things to keep in mind or problems when building Boost.Test as a shared library that was not built in the standard way (i.e. using bjam on each platform)? Best regards, Florian Winter