Re: [boost] [numeric_cast] request for boost::numeric_downcast

Subject: Re: [boost] [numeric_cast] request for boost::numeric_downcast
From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2008-11-14 08:57:32

Kim Barrett skrev:
> At 2:41 AM -0500 11/11/08, David Abrahams wrote:
>> boost::polymorphic_downcast is meant to be used where you think you
>> really know what derived type you've got, and you want an assertion to
>> reinforce your reasoning with a runtime check.  I suppose you can have a
>> similar situation for numeric types (e.g. "I know this long int should
>> fit in a short int").
>>
>> How about boost::checked_cast, or boost::checked_narrowing_cast or
>> boost::narrow_cast?
> 
> Is this any different from boost::numeric_cast with an asserting rather
> than throwing overflow handler, plus boost/numeric/conversion paying
> attention to BOOST_NO_EXCEPTIONS, possibly by using boost::throw_exception?

It depends. I can't remember how the overflow handler mechanism works, 
but we need to be able to have both types of casts in the same program.

-Thorsten