Re: [boost] Optimized portable isnan, isfinite, fpclassify etc

From: John Maddock (john_at_[hidden])
Date: 2006-10-12 11:21:01

Johan Råde wrote:
> 3. Your <limits> header is a bit funny.
> numeric_limits<T>::quiet_NaN() returns a NaN with the signbit set.
> This triggered the assertion.

You need to allow for the possibility that the sign bit is set anyway.

> (Does it matter? Maybe. According to C99, positive NaN should be
> written to text files as "nan" or "+nan"  and negative NaN as "-nan".
> And this will probably be part of C++0x as well.)

C++ doesn't guarentee any particular format for printing NaN's or Infinities 
:-(

John.