Public Comment Number PC-UK0133 ISO/IEC CD 9899 (SC22N2620) Public Comment =========================================== Date: 1998-02-25 Author: N.M Maclaren Author Affiliation: Self Postal Address: University of Cambridge, Computer Laboratory, New Museums Site, Pembroke Street, Cambridge CB3 3QG, United Kingdom E-mail Address: Telephone Number: +44 1223 334761 Fax Number: +44 1223 334679 Number of individual comments: 1 Comment 1. Category: Normative change to existing feature retaining the original intent Committee Draft subsection: 7.6.3.2 Title: fesetround is often unimplementable Detailed description: Many existing C implementations and even more numerical libraries have the property that they rely on the rounding mode they are called with being the one they were built for. To use a different rounding mode, the user must link with a separate library. The standard should permit an implementation to reject a change if the change is impossible, as distinct from when it does not support that mode at all. I suggest that paragraph 3 be reworded as: 3 The fsetround function returns a nonzero value if and only if the requested rounding direction has been established. It shall return zero if the direction does not match a rounding direction macro or in other implementation-defined circumstances.