Re: [boost] difference_type size()?

Subject: Re: [boost] difference_type size()?
From: Bo Persson (bop_at_[hidden])
Date: 2011-10-20 11:32:53

Jeffrey Lee Hellrung, Jr. wrote:
> On Wed, Oct 19, 2011 at 12:38 PM, <andrey.semashev_at_[hidden]> wrote:
>
>> On Wednesday, October 19, 2011 12:27:31 Jeffrey Lee Hellrung, Jr.
>> wrote:
>>
> [...]
>
>>>> I think the following would do:
>>>>  typedef typename make_unsigned< difference_type >::type
>>>> size_type;
>>>
>>> I was under the impression that most of the traits in
>>> Boost.TypeTraits of this nature are only defined for builtin
>>> types.
>>
>> See one of my previous replies, difference type should be a signed
>> integer type.
>>
>
> Ah, indeed.  Then I agree make_unsigned would be a legitimate
> solution.
>

This will break if difference_type is a UDT without a make_unsigned 
specialization.

Is that a good idea?

Bo Persson