Hi, I'm working around some issues in MPL with the evc4 (eMbedded Visual C++ 4) compiler. The compiler behaves just as a msvc6 one and includes files from "boost\mpl\aux_\preprocessed\msvc60\". In or_impl.hpp (and the same problem in and_impl.hpp) there is a defined for a templated "struct or_impl" and a specialisation for or_impl<false>::result_ after the struct. In evc4 the specialisation must be inside the class. The ..\msvc70\or.hpp implementation does this right for evc4. Now my question is how I should port the preprocessed sourcecode for evc4? Creating preprocessed files for evc4 somehow? Using the msvc70 files, given that it would work? Not using preprocessed files? I'm not familiar with this Boost library, I'm just porting it (as it gets used by many other libraries). bye Michael