__builtin_cpow((0,0),(0,0))

[Paolo Carlini]

Robert Dewar wrote:

> Paolo Carlini wrote:
>
>> Actually, sorry, __builtin_cpow returns (nan, nan) (got sidetracked 
>> by a strange issue I'm seeing in the C++ library), even "worse", so 
>> to speak...
>>
>> Paolo.
>
> Well it certainly seems the right result in this case to me. Does the
> standard really require the wrong result here?

You mean (nan, nan) is ok? Why, exactly? Isn't (1,0) more consistent 
with the behavior of real power? (*) The standard is rather vague, in my 
reading, allowing "spurious exceptions" in "special cases", thus 
allowing a plain cexp(c*clog(z)).

Paolo.

(*) This "intuition" is confirmed by a range of independent 
"appliances", like high quality HP calculators or Maple...