Re: [boost] [math] potentian bug: iround throws, given double( numeric_limits<int>::min() )

Subject: Re: [boost] [math] potentian bug: iround throws, given double( numeric_limits<int>::min() )
From: John Maddock (boost.regex_at_[hidden])
Date: 2011-10-20 07:27:04

> A thought came to my mind... Theoretically, is it possible for the 
> following
> conditions to be true?
> static_cast<float>( std::numeric_limits<int>::min() ) <
> std::numeric_limits<int>::min()
> static_cast<double>( std::numeric_limits<int>::min() ) <
> std::numeric_limits<int>::min()
> static_cast<long double>( std::numeric_limits<int>::min() ) <
> std::numeric_limits<int>::min()
> static_cast<float>( std::numeric_limits<int>::max() ) >
> std::numeric_limits<int>::max()
> static_cast<double>( std::numeric_limits<int>::max() ) >
> std::numeric_limits<int>::max()
> static_cast<long double>( std::numeric_limits<int>::max() ) >
> std::numeric_limits<int>::max()
> After all, casting to floating-point may loose precision... I have no
> knowledge in this area, so it may be just a silly thought.

Ah, yes: when I fixed this bug I had to disable some of new the tests for 
type float because of that very issue: an integer type converted to type 
float may actually be outside the range of an integer due to rounding during 
the conversion.

John.