Re: [Boost-users] [numeric conversation] behavior on std::numeric_limits<double>::max() + eps with numeric_cast

Subject: Re: [Boost-users] [numeric conversation] behavior on std::numeric_limits<double>::max() + eps with numeric_cast
From: Olaf Peter (ope-devel_at_[hidden])
Date: 2014-06-15 14:15:47

Am 11.06.2014 14:51, schrieb Brandon Kohn:
>
> On 6/11/2014 07:06 AM, Olaf Peter wrote:
>> Am 10.06.2014 18:28, schrieb Brandon Kohn:
>>> I should note that in each of these specializations care must be taken
>>> that bounds are properly checked given the context of the conversion
>>> direction. In my test I essentially converted the fundamental type to an
>>> instance of intrinsic_type (via the template constructor) and then used
>>> that to compare with the bounds of the intrinsic_type<T>. In a real
>>> world example this is possibly nonsense.
>> I thought this is what the checker does already, including test on NaN
>> and Inf. Could you explain this?
>>
> What I mean is that the range checker is checking the whether the values
> in the source instance can be represented in the target instance. So one
> must ensure that for a given conversion (like my_type -> int) a
> range_checker type exists which can perform that check. Your original
> checker did cover the types of checks needed, it just neglected to deal
> with the interfaces on the respective types (source/target.) Apologies
> if I'm stating the obvious.
>
> Let me know if you have any more issues. I'm happy to help.
Thank you!

Is there a way to override the default implementation for e.g. double? 
The attached example fails to compile due to
redefinition of 'struct boost::numeric::numeric_cast_traits<double, double>'

Thanks,
Olaf