(j3.2006) (SC22WG5.4180) [ukfortran] Urgent: letter ballot on interps
Fri Feb 12 10:27:56 EST 2010
Malcolm Cohen wrote:
> Bill Long wrote:
>> N.M. Maclaren wrote:
>>> On Feb 10 2010, Bill Long wrote:
>>>> Comment for F03/0039 - HYPOT()
> No, there is no temptation and no possibility for confusion.
> That is because the Note in question does not exist in F08. We deleted it
> specifically because it created more confusion than enlightenment.
Of course, you are right. I was looking a a printed 09-007r1 version at
the time. Sorry about that.
However, I believe I should have made another comment on this interp
stronger. I said
Further, instead of somewhat obscure
HYPOT = SQRT(-1.0)
why not be clear about the intent and write
HYPOT = IEEE_VALUE(X, IEEE_QUIET_NAN)
More than "obscure", the proposed code is not even legal. The SQRT
function explicitly requires that a real argument be >= 0, so SQRT(-1.0)
has no interpretation in the standard. The expected outcome of trying
to compile this example would be a hard error at compile time. Even
more reason to go with the alternative, which is not only valid code,
but effectively self-documenting, and does exactly what is desired.
(That said, I still would prefer no edit at all.)
Bill Long longb at cray.com
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