[Cfp-interest] draft of meeting notes for 19 April 2012

[David Hough CFP]

19 Apr 2012 CFP Meeting Notes

Attendees: David, Fred, Jim, Rajan, Joel

Action items from 15 March -

 Jim revised part I draft and submitted to WG, based on March meeting discussion.

Next meeting Thursday 10 May.


Issues in draft:

Issue 1: Is requiring freestanding support for part of a header OK?

 New idea for C standard.   No adverse comment yet from WG14
 In document now.
 Consensus no change.

Issue 2: Break F.1 into three paragraphs for clarity.
 Consensus: OK.   No substantive changes.

Issue 3: Better to restrict the format specifiers that strfrom must support?

 Don't need other stuff for simple data transfer.
 Omits many formatting options and "*" precision at run time and ellipsis -
 allowed but not required.    Means specifying subset that programmer can't
 extend to get full function.

 Consensus: add ellipsis to minimum subset, allow implementation by snprintf.
 Not require * precision.
 AI: Jim to write up.

Issue 4: Do we need wide character strfrom?    (hosted only, freestanding 
 doesn't have wide char)

 Rajan: many customers using wide characters.

 First consensus: add wide char support.   
 But: superfluous, other ways of doing this on hosted implementations.
 AI: Jim to remove issue.

Issue 5:  Appropriate for FP spec to specify integer strfrom functions?

 Rajan: no, stick to FP.

 Jim: no code portability issue, only a vague sense of incompleteness,
 not sufficient reason.

 Consensus: remove integer strfrom from draft, superfluous on hosted imps.
 AI: Jim to remove issue.

ISSUE 6: The macro names FP_CEIL, etc. might suggest results will be in floating types.

 Jim: change to different macros to avoid confusion.
 AI: Jim to document a different set of macros.

ISSUE 7: Should the 7.12 specification of llogb require a domain error for finite out-of-range cases?

 C comm will resolve DR that will decide.
 AI: Jim to remove issue.

ISSUE 8: Forward references need to be added throughout.

 Handle when finally finished, but move the issue to beginning of document.
 AI: Jim to move issue to front.

Fred's issues:

1) fsqrt domain error occurs if the argument is less than zero

agreed - wording from C11

AI: Jim to change.

2) snan initializer for thread local storage - same as for static initializer
   7.12#5

Jim: is this already implicit, so we don't need to state?   C11 uses
"initializer of static duration" for static var and thread local.
Also uses "static or thread storage duration".

AI: Fred to find right C11 wording for snan initialization for thread local
storage.

3) canonicalize function: needs footnote that two arguments can point to same
object, in which case canonicalize in place.

 do simple objects ever overlap partially?    can happen in unions.

 AI: Jim to add footnote addressing issue.


What to do next?


Part 2 of spec is to be Decimal.   Different kind of job:
update of existing spec.    Lots of formatting required.
Fred has a proposed document of changes.

Part 3 is interchange and extended.    Should be mostly done already. 

Don't want to inundate WG14 with lots of little updates.

AI: Jim to talk to John Benito to determine best approach to developing
other parts,
interaction with WG14, and posting document for public review.

AI: Jim to investigate moving decimal document into approved template.
All done in Word.    Nobody else volunteered to help.   Jim hopes to hear
from such a volunteer.


Leftover issue raised by Joel:

Jim's note:

http://mailman.oakapple.net/pipermail/cfp-interest/2012-April/000334.html

tgmath and constant rounding mode spec:
How does specification of constant rounding mode affect tgmath functions?
We stated that they are affected.

We've also stated that the functions so affected are those listed in Table 2
whose macro expansion has not been suppressed.    So what happens when macros
are suppressed? 

We are pinning down C11 behavior that wasn't fully defined.

Joel: tgmath might have to reimplement macros instead of rewrapping.

We need to work on this issue next time.

AI: Joel to write up a note.