Re: [Boost-users] How to make is_arithmetic true for a UDT

Subject: Re: [Boost-users] How to make is_arithmetic true for a UDT
From: John Maddock (boost.regex_at_[hidden])
Date: 2012-07-12 05:31:31

>I am facing the need to get my User Defined Type to return true from
>
>  boost::is_arithmetic

You don't, a UDT is not an arithmetic type (according to the type system 
which is what type_traits honors) it's a class type.

> (This is to meet a check for autoprefixing in Boost.Units)

Looks like there are two places this is used in Units - and both are 
implementation details - for auto-prefixing looks like you need to overload 
autoprefix_norm for your type.  The other use is in 
is_non_narrowing_conversion, which you would [partially-] specialize for 
your type.

Hope that makes sense, John.