[Boost-users] How to add a type to is_arithmetic

Hi, Suppose I define a class fixed_point as class fixed_point{ ....some operations are defined here private: int _integer_part; unsigned _fractional_part } I want is_arithmetic<fixed_point>::type to be true_ Of cause, I can partially specialize the template class as template <> struct is_arithmetic<fixed_point> { ... blah blah }; If I use the above approach, shall I put it into the namespace boost or not? Also, I'm wondering if there is any generic way to do this? Thanks, Peng