[Cfp-interest] Meeting minutes for 2013/04/11 C FP Study Group

Fri Apr 12 08:21:56 PDT 2013

I left in a private note (the *'d part) in the notes I sent out yesterday. 
Please ignore that line since I'll elaborate here:

I have four alternatives I'd like to propose in order of preference for 
the quantexpdN and quantexpdNx functions:

1) For the common (and likely only) cases where int is large enough, leave 
it as is. i.e. We explicitly list the "too large for int" case as 
unspecified what the implementation does.

2) Use a _DecimalN return type.
int quantexpdN(_DecimalN x); -> _DecimalN quantexpdN (_DecimalN x);
The _DecimalN return value would be a canonical value. The hope is that 
larger N values will give larger ranges in the return value automatically 
and there is no need to introduce new types.

3) Have the implementation define a macro for extended types if the 
exponent is out of range of an int with the value of a function name that 
can handle the larger types (and no macro defined for ones that fit in 
int):
Ex. __DECIMAL1024_HAS_LARGE_QUANTUM_EXPONENT quantexpd1024_returns_long

4) Use int_leastN_t types where the implementation has to define new 
int_leastN_t types.
This has the drawback of having to potentially introduce new int types (ex 
For _Decimal128 since not all implementations have 128 bit integer types).

Regards,

Rajan Bhakta
z/OS XL C/C++ Compiler Technical Architect
ISO C Standards Representative for Canada
C Compiler Development
Contact: rbhakta at ca.ibm.com, Rajan Bhakta/Toronto/IBM
Telephone: (905) 413-3995

From:
Rajan Bhakta/Toronto/IBM at IBMCA
To:
CFP <cfp-interest at ucbtest.org>, 
Date:
04/11/2013 03:07 PM
Subject:
[Cfp-interest] Meeting minutes for 2013/04/11 C FP Study Group
Sent by:
cfp-interest-bounces at oakapple.net

Attendees: Fred, Jim, Marius, Ian, David 

Old action items: 
  Jim to post spreadsheet: Done 
  Jim to check if a new WG14 document number is needed: Yes. Done 
  Ian and Rajan to review intro: Good as it is. Done 
  Jim to describe more changes: Done 

Next meeting: May 16th, 2013 

New action items: 
  AI: Jim to check with David to go back to old conference number 
  AI: Jim to send out an email to see if 12:30-2:30 pm EST (30 minutes 
earlier than the original time) is OK for time - Consensus to do this on 
the call so no email needed. 
  AI: Jim to send new words for Part 1 comment 17. 
  AI: Jim to send new words for Part 1 comment 25. 
  AI: Everyone to review Part 2 to make sure it is ready for full official 
WG14 review 

Discussion: 
  Fred: Have we resolved how we are working as a subgroup of WG14? Two 
wikis for example. 
  Jim: Not going very well since he is still doing double posting. Awkward 
situation. 
  Rajan: Is Secure C doing this? They seem to be doing their own on the 
side without too much WG14 impact. 
  Fred: Prefer keeping this separate 

Part 1 comments: 
  Jim: Proposed new text is what the comment submitter posted. John Benito 
suggested we add a column for our response. 
  Comment from Willem Walker: Change all "Suggested changes to C11" to 
"Changes to C11" in our document. Consensus is to make the change. 
  Comment from Joeseph Myers regarding Table 2 and wchar functions and 
atof. Consensus is to make the change. 
  Spreadsheet comments and consensus: 
    1-2: Make the changes 
    3: Remove first line only 
    4: No main doc changes 
    5: Remove the second instance. 
    6: Fred: Reorder the 5 section for all 3 documents. 
      Accept changes. 
    7: Accept changes. 
    8 (wprintf, wscanf): Accept changes. 
    9: Discussion about how to format. Decided on round dark bullets and 
no punctuation. 
    10: Accept changes. Change line number to 24 in the comment. 
    11 (log function typeface): Accept changes. 
    12: Accept changes. 
    13: Accept changes. 
    14: Accept changes. 
    15: Accept changes. 
    16: Accept changes. 
    17 (llogb): Need to reword this. AI for Jim to do. 
    18: Accept changes. 
    19: Accept changes. 
    20: Accept changes. 
    21: Accept changes. 
    22 (real floating): Rajan: math.h so shouldn't have complex. Jim: 
Consistent with others if we do not accept complex. Accept changes. 
    23: Accept changes. 
    24 (four macros vs three): Accept changes. 
    25: David: Need a way to find out if it is signalling without 
signalling. 
      Jim: Wide evaluation is the issue. 
      David: Should only apply to variables, not expressions. 
      Jim: Works for variables and expressions generally. 
      David: Add a reference to F.3. 
      Fred: How about F.3#5? 
      Jim: The standard never references paragraph numbers. 
      AI: Jim to show the words of the F.3 reference being a footnote. 
    26: Accept changes. 
    27 (imput): Accept changes. 
    28: Accept changes. Add parenthesis for clarity as well. 
    29: Accept changes. 
    30: Accept changes. 
    31 (old): Accept changes. 
    32: Accept changes. 
    33: Accept changes except the line 25 change. Also remove the bold and 
typeface of "and" on line 11. 

Part 2 review: 
  Jim: I want to make this follow Part 1 by one WG14 meeting. This means 
we can have a WG14 review in May or June for this. 
  Example 3 on page 29: Output is in "e" format now. 
  Jim: A number of other editorial changes made. 

Part 3: 
  This Spring 2013 meeting will be the first time the full WG14 will see 
Part 3. 
  This means we need Part 4 draft for early September to get into the 
October mailing. 
  The changes to the type system is risky so needs to be looked at 
closely. 
  Issue: quantexpd* functions may have the exponent > INT_MAX so the 
return type would not work (overflow) 
  *I can send a note suggesting _DecimalN as the return type 
  Type generic should be looked at still. 

Regards,

Rajan Bhakta
z/OS XL C/C++ Compiler Technical Architect
ISO C Standards Representative for Canada
C Compiler Development
Contact: rbhakta at ca.ibm.com, Rajan Bhakta/Toronto/IBM
Telephone: (905) 413-3995_______________________________________________
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