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

Peng Yu wrote:

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::type to be true_

The aim of is_arithmetic is that it returns true only for built-in arithmetic types: in other words it's a type introspection tool. If you specialise it for UDT's you will very likely break other code (for example has_trivial_XXX assumes that all arithmetic types have trivial construct/asign/copy/destroy operations). Probably the correct traits to be specialising (and using to detect "numbers") is std::numeric_limits. HTH, John.