(j3.2006) exception message on termination

[Daniel C Chen]

XLF compiler has an option to report fp exceptions including underflow and
inexact.  It is default OFF.

Daniel

XL Fortran Development - IBM Toronto Software Lab
Phone: 905-413-3056
Tie: 969-3056
Email: cdchen at ca.ibm.com
http://www.ibm.com/software/awdtools/fortran/xlfortran



From:	Robert Corbett <robert.corbett at oracle.com>
To:	fortran standards email list for J3
            <j3 at mailman.j3-fortran.org>,
Date:	06/12/2013 04:06
Subject:	Re: (j3.2006) exception message on termination
Sent by:	j3-bounces at mailman.j3-fortran.org



Thinking back on it, most of the complaints we received were about
underflow
also.  Underflow is usually harmless in codes such as root finders and
quadrature routines.  On the under hand, underflow can cause silent bad
results
in some matrix computations.

Robert Corbett



On 06/12/13 00:38, Malcolm Cohen wrote:
> The only complaint we got was for reporting underflow, so we added an
option to
> suppress that one.
>
> We never report inexact.  I agree it is completely pointless to report
inexact,
> in my opinion it was an oversight not to make than an exception to the
reporting
> rule.
>
> Cheers,
>
> -----Original Message-----
> From: Robert Corbett
> Date: ?? 25?6?12? 12:59
> To: j3
> Subject: (j3.2006) exception message on termination
>
> Can we delete the second and third sentences of paragraph 2 in Clause 8.4
in the
> upcoming revision?  They state
>
>        If an exception (14) is signaling on that image,
>        the processor shall issue a warning indicating
>        which exceptions are signaling; this warning
>        shall be on the unit identified by the named
>        constant ERROR_UNIT (13.8.2.8).  It is recommended
>        that the stop code is made available by formatted
>        output to the same unit.
>
> Sun FORTRAN 77 produced such output.  It was a constant source of
complaints
> from users.  As bad as Sun FORTRAN 77 was in this regard, it did not
report
> inexact exceptions, as is required by the text of the standard.
>
> Robert Corbett
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