[boost] call_traits

Why doesn't the following compile? I get the error "foo: function does not take 1 arguments" on VC8. #include <boost/call_traits.hpp> template < typename P1 > void foo ( typename ::boost::call_traits < P1 >::param_type p1 ) { } int main ( ) { foo ( 42 ); // error here return 0; } (Background info: I would like to use this technique to generate optimized forwarding functions that do not know anything about the function being forwarded to. Overloads taking any number of params would be generated with the boost preprocessor library.) -Jason