Public Comment Number PC-UK0137

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: <nmm1@cam.ac.uk>
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: 7.7

Title: Allow infinities and NaNs for each precision


Detailed description:

A major flaw in paragraphs 4 and 5 is that there is no way of specifying an
infinity or a NaN for double or long double, unless float supports them.
While this is the common case, C9X does not require it and it is not
reasonable to do so.  I can see no good reason not to have three symbols
for each, exactly as for HUGE_VAL.  I suggest changing 'float' to 'double'
in paragraph 4 and adding the following:

    The macros

        INFINITY_F
        INFINITY_L

    are respectively float and long double analogs of INFINITY.

and changing 'float' to 'double' in paragraph 5 and adding the following:

    The macros

        NAN_F
        NAN_L

    are respectively float and long double analogs of NAN.