Public Comment Number PC-UK0162 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: 6.2.1.6 Title: Complex infinities and NaNs Detailed description: This is seriously incompatible with the spirit of IEEE 754 and LIA-1, in that information can be lost without flagging the fact in any way. Far worse, it REQUIRES complex infinities and NaNs to be converted to finite numbers with no indication of the fact. This is not reasonable. I suggest changing 6.2.1.6 paragraph 2 to say: 1 When a value of complex type both of whose components are finite real numbers is converted to a real type, the imaginary part of the complex value is discarded and the value of the real part is converted according to the conversion rules for the corresponding real type. When a value of complex type either of whose components is an infinity or a NaN is converted to a real type, the result is implementation-defined. And adding the following: Recommended practice If the implementation supports the concept of complex infinities, the result of converting a real infinity to a complex type should be a complex infinity and that of converting a complex infinity to a real type should be a positive infinity. If the implementation supports the concept of complex NaNs, the result of converting a real NaN to a complex type should be a complex NaN and that of converting a complex NaN to a real type should be a NaN. [ Note that conversion WITHOUT raising exceptions is provided by the creal and cimag functions, so this is not a restriction. ]