J3/05-111 Date: 4 Jan 2005 To: J3 From: Fred Tydeman Subject: Signbit of NaN NUMBER: F03/0032 TITLE: Sign bit of IEEE NaN KEYWORDS: IEEE-754, NaN, sign bit, negative DEFECT TYPE: Contradiction ??? STATUS: For consideration QUESTION: Do IEEE-754 NaNs have a sign bit? Can they be negative? Does a sign bit imply a value can be either positive or negative? DISCUSSION: Fortran 2003 in 14.10.2 (IEEE_COPY_SIGN) says that NaNs have a sign bit. But, 14.10.10 (IEEE_IS_NEGATIVE) says NaNs are not negative. This appears to be a contradiction between two parts of Fortran 2003. ANSWER: EDITS: All edits refer to 04-007.pdf. SUBMITTED BY: Fred Tydeman HISTORY: J3/05-111 m171 Submitted