(j3.2006) FRACTION: zeros, infinities and NaNs

Robert Corbett Robert.Corbett
Thu Sep 25 21:50:58 EDT 2008


Van Snyder wrote:
> Robert Corbett wrote:
> 
>>Bill Long wrote:
>>
>>  
>>
>>>The changes for FRACTION for f08 are in paper 07-200r1, which includes 
>>>extensive explanation.  These changes were a small part of Interp 
>>>F03/0042 that was filed against f03.
>>>    
>>
>>I considered the possibility that there was an interp that
>>changed the semantics of FRACTION.  I didn't find one.  The
>>text of F03/000042 still proposes that FRACTION(Inf) = Inf.
>>
>>The paper 07-200r1 makes it clear that the change is an
>>incompatible change from Fortran 2003.  The committee's
>>response to one of my comments on CD 1539-1 said that all
>>incompatible changes are listed in Section 1.5.  This one
>>is not listed there.
> 
> Actually the response said we thought we caught them all, and that we 
> would add any that we missed.  The intent is that the list be 
> exhaustive, not that it be a partial list with a caveat that says it's a 
> meaningless subclause because it's only a partial list.

Regardless of intent, the list has not been exhaustive for the
past three editions of the Fortran standard, and I doubt it will
be for the new edition.  The compatibility clause tends to list
the big changes and miss the little changes, although some big
changes have failed to make the list.  Simply saying that the list
is exhaustive does not make it so.

Bob Corbett



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