Submitter: Fred J. Tydeman (USA)
Submission Date: 2010-06-17
Subject: Clarification to fmod

Consider:

• fmod(INFINITY,NAN)
• fmod(NAN,0.0)

Do they raise the "invalid" floating-point exception? Or, do they return a NaN without raising any floating-point exceptions? The issue applies to F.10.7.1 The fmod functions

fmod(x,y) returns a NaN and raises the "invalid" floating-point exception for x infinite or y zero.

versus F.10 Mathematics, paragraph 11.

Functions with a NaN argument return a NaN result and raise no floating-point exception, except where state otherwise.

Proposed fix to F.10.7.1 The fmod functions:

After "x infinite or y zero", add "and neither is NaN".