This is very strange given that boost::switch has been dwnloaded from Vault 1637 times as of now. But just including #include <boost/switch.hpp> Gives a compile error with MSVC 2008 under Vista: 1>boost/switch.hpp(62) : error C2785: 'R boost::switch_detail::forced_return(boost::remove_reference<T>::type *)' and 'void boost::switch_detail::forced_return(const void *)' have different return types 1> boost/switch.hpp(54) : see declaration of 'boost::switch_detail::forced_return' 1> boost/switch.hpp(62) : see declaration of 'boost::switch_detail::forced_return' 1>boost/switch.hpp(62) : error C2912: explicit specialization; 'void boost::switch_detail::forced_return<const void>(const void *)' is not a specialization of a function template 1>boost/switch.hpp(62) : fatal error C1903: unable to recover from previous error(s); stopping compilation I used Linux/gcc till now without problems, but I wonder there is something wrong in my MSVC setup because I would guess not all the 1637 people that have downloaded switch.zip use gcc. Marco