Hi, I'm trying to use typedef typename boost::mpl::if_ to choose between two structures, both with identical function names, so I can choose which function to call based on the template parameter type. The code works fine on Visual Studio 2005. But in MinGW/MSys it returns: RPC3_Boost.h:203: error: template argument 2 is invalid RPC3_Boost.h:203: error: template argument 3 is invalid RPC3_Boost.h:203: error: ISO C++ forbids declaration of `type' with no type This is with boost_1_35_0. I've cut out as much code as I can: struct ReadBitstream { static void apply(RakNet::BitStream &bitStream, RakNet::BitStream* t) {/* ... */} }; template <typename T> struct ReadPtr { static inline void apply(RakNet::BitStream &bitStream, const char *&t) {applyStr(bitStream, (char *&) t);} }; template< typename T > struct DoRead { typedef typename boost::mpl::if_< boost::is_convertible, typename ReadBitstream, typename ReadPtr<T> >::type type; }; To call the function, I use: DoRead< boost::remove_pointer<T>::type >::type::apply(* (args.bitStream),&t); Thanks in advance for any help. The whole file is here if you need to see more code: https://raknetjenkinsso.svn.sourceforge.net/svnroot/raknetjenkinsso/trunk/De...