template<class Arg1, class Arg2, class Result>
struct std::binary_function< Arg1, Arg2 &, Result >
a missing type for passing in things by reference, should be in STL needs to be in std namespace, because it is a specialization of binary_function defined in <functional>
Member Typedef Documentation
template<class Arg1, class Arg2, class Result>
typedef Arg1 std::binary_function< Arg1, Arg2 &, Result >::first_argument_type
template<class Arg1, class Arg2, class Result>
typedef Result std::binary_function< Arg1, Arg2 &, Result >::result_type