To: J3 07-281
From: Bill Long (original from Michael Ingrassia)
Subject: Interp F03/0079
Date: 2007 November 14
The only action taken at meeting #175 was that this interp was
accepted as an interp "to be processed".
NUMBER: F03/0079
TITLE: Value of decimal exponent for a real zero value
KEYWORDS: Data edit descriptors, Numeric editing, decimal exponent,
zero value
DEFECT TYPE: ERRATUM
STATUS: J3 consideration in progress
QUESTION:
In formatted output, what is the value of the
decimal exponent produced for a real zero value
under the D, E, EN, ES, and G edit descriptors?
SUGGESTED ANSWER:
In such a case, the decimal exponent should have
the value zero whether or not a nonzero scale factor
is in effect. Edits are supplied to make this clear.
DISCUSSION:
The Fortran 2003 standard does not specify what the value of the
decimal exponent of a real zero value should be under formatted
output. Every implementation of which Sun is aware uses the value
zero for the decimal exponent unless a nonzero scale factor is in
effect. Different implementations format real zeros differently under
nonzero scale factors, but the difference is mainly in the form of the
mantissa and not the exponent.
The C and C++ standards both explicitly state that the value of the
decimal exponent produced for the real value zero under a format that
includes an exponent is zero. The Fortran standard should also.
EDITS:
[227:15+] At the end of the numbered list in 10.6.1 "Numeric
editing", add:
"(7) On output of a real zero value, the digits in the
exponent field shall all be zero, whether or not
a nonzero scale factor is in effect."
SUBMITTED BY: Michael Ingrassia
HISTORY: 06-125 m175 F03/0079 Submitted
07-XXX m182