To: J3 07-282r2
From: Bill Long (original from Michael Ingrassia)
Subject: Interp F03/0080 Formatted output of a negative real zero value
Date: 2007 November 14
NUMBER: F03/0080
TITLE: Formatted output of a negative real zero value
KEYWORDS: formatted output, negative zero, IEEE
DEFECT TYPE: ERRATUM
STATUS: J3 consideration in progress
QUESTION:
Suppose a Fortran processor's representation of the real zero
value is signed. When a negative real zero value is written
using formatted output, does the Fortran 2003 standard require
the representation of the zero value in the output field to be
prefixed with a minus sign?
ANSWER:
Yes, the negative sign is required to appear in formatted output
of a negative zero value. In subclause 10.6.1, list item (3) at
[227:3-4] says "The representation of a negative internal value
in the field shall be prefixed with a minus sign." For a
processor that distinguishes between positive and negative zero,
there is no exemption for output at [38:1-6]. For the case of
IEEE reals, the IEEE_IS_NEGATIVE function at [375:25] explicitly
says that -0.0 is "negative".
EDITS:
none.
SUBMITTED BY: Michael Ingrassia
HISTORY: 06-126 m175 F03/0080 Submitted
07-282r1 m182