[cfp-interest 3414] TC1/SC22/WG14/CFP 2025/03/12 Meeting minutes

[Jerome Coonen]

2025/03/12: 8:00 AM PDT
[Please submit proposed changes to these minutes to Jerome or to the group.
Revision changes appear at the bottom.]

*Attendees*

    Jim Thomas, Rajan Bhakta, Jerome Coonen, Damian McGuckin, Tue Ly,
Maryam Karampour, Joshua Cranmer, David Hough, Fred Tydeman



*Agenda plus new items*

   https://wiki.edg.com/pub/CFP/WebHome/n3516.pdf – These minutes should be
read alongside the agenda, with its many reference links.


*Previous meeting notes*

    https://wiki.edg.com/pub/CFP/WebHome/n3515.pdf


*Study group logistics*

    Next meeting: 16 April 2025, 8:00 AM PDT

    ISO Zoom teleconference

    Please notify the group if this time slot does not work.

    David: Has the server attackers at bay, for now.


*C documents*

    There is a new C2Y draft 3467 Feb 2025.
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3467.pdf

    C23 has been published ISO/IEC 9899, available for purchase.
https://www.iso.org/standard/82075.html

    Jim: Please note the new draft, a fairly  quick update from the
previous version.



*IEEE 754 liaison*

    David & Damian & Jerome: Much discussion but change is slow. A major
topic is the fate of the 16-bit floating type.



*C++ liaison*

    Joshua: Meeting of the numeric subgroup in recent meeting. The move to
deprecate the fp environment still on the table.



*WG14*

    Rajan:All papers but one were accepted. The paper on frexp and type
double double has uncceptable language. WG14 had several ideas but no
specific suggestion.

    Quoting Rajan from chat: These are models outside the C model. Should
be in the library introduction section (7.1.4), "For the functions in
math.h, if the implementation does not follow the model in 5.2.5.3.3, the
results for the functions will be unspecified."

    Jim: Takes new action to offer a proposed fix arrived at in discussion.


    Rajan: SIGFPE -- went with Action 4 in Fred's paper, n3378c:
        https://wiki.edg.com/pub/CFP/WebHome/n3378c.htm.


    Rajan: CFP got a round of applause from WG14. (Story told twice by
popular demand.)


    Rajan: New draft of N3390 coming from Alex Celeste. The issue is
whether the imaginary "I" is a constant or macro.
        https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3390.htm


    Jim & Rajan: WG14 is developing a new process for simple wording
changes to papers pending approval. This should expedite workflow.


    Jim: Is it possible to support the imaginary types as a "pure
extension", that is, not invalidating the implementation

        Rajan: Yes

        Jim: Can the current definitions be preserved? What about the
imaginary suffix?

        Rajan: The imaginary suffix is part of the standard, so the new
interpretation would be a change to the standard.

        Jim & Damian: The crux of of the matter is how to express "1.0i" as
a pure imaginary unit when the standard defines it as a complex value with
a possibly troublesome signed real part.



*TS-4 and TS-5 revisions*

    Jim: Links in the agenda lead to drafts with a banner showing that
final updates are due to be published "soon".


*C23 integration*

    None.


*Carry-over action items from last meeting *

    Damian: complex.h intro, cproj, and editorial suggestions.

        Damian: Might have a paper on the complex.h Intro up next week.
cproj is done.


*Action items from last meeting *

    David: Draft statement on midpoint and interpolation.

        David: Done and forwarded by Rajan to WG14, where it was accepted.


    Ly (spontaneous item): Will the complex library ever match the real
library? E.g. cube root or sinepi?

        Jim: This will be considered for future discussion.

    Jim: Review the comments on TS 5.
         Done, with suggestions accepted by ISO, so they will appear.

    Jerome: Rework the proposal for functions rounding to a narrow type.
Finish by 19 Feb for Rajan to take to WG14 meeting.
        Done and passed.

    Jim: Write a paper proposing editorial changes for imaginary suffix,
emphasizing editorial changes vs. technical changes.

        Done as WG14 paper n3500, due for next meeting.



*Discussion of issues*

   Action item from WG14

        Rajan: N3447 deals with evaluation of constants at compile time,
outside the execution environment.

        Jim: Proposes better wording for the description, which Rajan takes
an action for.


    Midpoint and interpolation functions in C

        Rajan: WG14 is happy with David's reply.


    cproj cleanup

        Jim: All of the other complex functions are defined generally
across the family. But cproj has a definition in terms of type double. An
added sentence makes that difference clearer.

        Jiim: Offers several comments re. the form of the proposal, with
options to prepare in Word, or Google Docs, or elsewhere.

        Fred: Process comment -- I do my proposals in raw html.


    complex.h introduction

        taken as an action item.


    Errors in draft 3435

        Jim: Parenthetical about "infinitary" is not yet removed but Rajan
says it's in the works.

    Imaginary I macro and i suffix issues
        Jim: Rajan has proposed fixes and the change is coming.


*Other issues:*
    WG 14 proposal process
        Jim: Discussed earlier.

    nexttoward exceptions
        Ly: The issue is raising exceptions for 0 or subnormal results.
It's not clear that one or both of ERRNO and the fp exceptions must be
indicated if the result is subnormal or zero. Whether it's raised is
implementation-defined in the standard. Annex F does not have that latitude.
       Ly: In Linux, we don't want to spend the execution time to signal
the exception.. Linux has the newer forms nextup and nextdown but they're
not generally available in programming environments.

*Adjournment*

    9:26 AM PDT

-----------------------------------------------


*Action items to be carried over:*

    None.


*New action items:*

    Jim: Draft a paper with suggestion for frexp and double double to
address the WG14 objections.


    Rajan: Send a note to WG14 about the N3447 issue.


     Damian & Jim: Tune up the cproj proposal suitable for WG14.


    Ly: Send email to CFP about the next____() issues.


*Discussion issues to be carried over:*

    None.

Respectfully submitted.

-Jerome Coonen
 650.996.4738
 jcoonen at gmail.com
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