[fortran] patch for PR 12839 - incorrect IO of inf

[Bud Davis]

On Wed, 2004-03-24 at 07:38, Paul Brook wrote:
>   
> I think it's probably worth asking on comp.lang.fortran about this.
> 
> Paul

below is the posting to clf:

Some question arose while implemnting this F2003 change to "Fw.d"
output in gfortran. The issues are small, but some help from the
experts on clf would be appreciated.

  
>From page 228 of the (draft) standard:

"For an internal value that is an IEEE infinity, the output field
consists of blanks, if necessary, followed
by a minus sign for negative infinity or an optional plus sign
otherwise, followed by the letters 'Inf ' or
'Infinity', right justified within the field. If w is less than 3, the
field is filled with asterisks; otherwise,
if w is less than 8, 'Inf ' is produced."

Is the following output:

FMT   neg inf  pos inf      nan
F1.0        *        *        *
F2.0       **       **       **
F3.0      ***      ***      NaN
F4.0     -Inf     +Inf      NaN
F5.0     -Inf     +Inf      NaN
F6.0     -Inf     +Inf      NaN
F7.0     -Inf     +Inf      NaN
F8.0     -Inf     +Inf      NaN
F9.0-Infinity+Infinity      NaN


from the following code:

          real nan,neg_inf,pos_inf,zero
          zero = 0.0
          pos_inf =  1.0/zero
          neg_inf = -1.0/zero
          nan = zero/zero
          print*,'FMT   ','neg inf ',' pos inf ','     nan'
          print '(A,8X,F1.0,8X,F1.0,8X,F1.0)','F1.0',neg_inf,pos_inf,nan
          print '(A,7X,F2.0,7X,F2.0,7X,F2.0)','F2.0',neg_inf,pos_inf,nan
          print '(A,6X,F3.0,6X,F3.0,6X,F3.0)','F3.0',neg_inf,pos_inf,nan
          print '(A,5X,F4.0,5X,F4.0,5X,F4.0)','F4.0',neg_inf,pos_inf,nan
          print '(A,4X,F5.0,4X,F5.0,4X,F5.0)','F5.0',neg_inf,pos_inf,nan
          print '(A,3X,F6.0,3X,F6.0,3X,F6.0)','F6.0',neg_inf,pos_inf,nan
          print '(A,2X,F7.0,2X,F7.0,2X,F7.0)','F7.0',neg_inf,pos_inf,nan
          print '(A,1X,F8.0,1X,F8.0,1X,F8.0)','F8.0',neg_inf,pos_inf,nan
          print '(A,F9.0,F9.0,F9.0)','F9.0',neg_inf,pos_inf,nan
          end

standard conforming ?


Specific questions are:

pos inf, F3.x, should it be "***" or "Inf" ?
pos inf, F8.x, should it be "    +Inf" or "Infinity" ?


Reply to the newsgroup or direct, please.  I will gladly read them
all.


thanks,
bud davis
bdavis9659@comcast.net