Re: [boost] Boost.config limits_test testcase and qnan checks.

Subject: Re: [boost] Boost.config limits_test testcase and qnan checks.
From: Thomas Klimpel (Thomas.Klimpel_at_[hidden])
Date: 2012-07-13 14:07:45

Matthew Markland wrote:
> default it runs at a higher optimization level then other compilers.  Gcc will fail
> this portion of the test if you compile with optimization on and -ffast-math.
> 
> My question is whether it is valid to test the qnan behavior when a platform
> does not claim compliance?

I wonder how you measure "claim compliance"? I once had a long debug session with gcc-4.5.2 before I found out that the builtin "is_nan" was returning wrong results. Isn't compiling the code that uses "is_nan" without warning also some sort of "compliance claim"? I know you are probably referring to "numeric_limits<double>::is_iec559", but on which floating point functionality can I still rely as a programmer if (is_iec559 == false)?

Regards,
Thomas