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Re: [wg14/wg21 liaison] C and C++ Compatibility Dec Agenda

From: Aaron Ballman <compatibility.sg.chair_at_[hidden]>
Date: Thu, 9 Dec 2021 08:09:05 -0500
Reminder: this meeting will be happening TODAY (not our usual Friday)
in about five hours from now. Hope to see you there (and remember, the
meeting password changed, see below for details)!


On Tue, Nov 30, 2021 at 1:10 PM Aaron Ballman
<compatibility.sg.chair_at_[hidden]> wrote:
> Our next meeting will be on Thur Dec 9, 2021 at 18:00 UTC
> (https://www.timeanddate.com/worldclock/converter.html?iso=20211209T180000&p1=tz_pt&p2=tz_mt&p3=tz_ct&p4=tz_et&p5=1440&p6=tz_cet).
> You can join the meeting at https://iso.zoom.us/j/5513145100
> **NEW PASSWORD: same as the old one, but spelled as a C reserved
> identifier instead of a C++ keyword; contact Aaron Ballman if you have
> questions **
> We will be discussing the following papers:
> WG14 N2808 (http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2808.htm)
> Allow 16-bit ptrdiff_t again
> Proposes changing the current minimum size for ptrdiff_t from 17 bits
> down to 16 bits on both hosted and freestanding implementations. This
> proposal was provisionally adopted for C23 and the author is
> especially interested in feedback about blocking implementation or
> compatibility concerns that WG14 should be aware of before formally
> adopting the feature.
> P2460 (https://wg21.link/P2460R0) Relax requirements on wchar_t to
> match existing practices
> Proposes to remove the constraint as to which encoding is associated
> with wchar_t, as is commonly done in existing practice. The author
> believes this should not have significant impact on cross-language
> compatibility as it is relaxing a constraint, but is interested in
> feedback confirming or refuting that belief.
> P1494R2 (https://wg21.link/p1494r2) Partial program correctness
> This paper proposes restricting "time-travel optimizations" with
> "execution epochs" that have independent guarantees about their
> observable behavior in the absence of undefined behavior. The proposal
> introduces a new library facility (requiring compiler magic) to
> specify the boundaries of these epochs. Examples, some of them of use
> with contracts, are provided. The author is looking for information
> about interest in the direction in the C community (which shares the
> execution model) as well as implementation or compatibility concerns.
> Thanks!
> ~Aaron

Received on 2021-12-09 07:09:22