On Wed, Jun 24, 2026 at 3:17 AM Steve Downey via SG16 <sg16_at_[hidden]>
wrote:

> SG16 Will meet tomorrow at 3:30 PM Zoom link
> https://iso.zoom.us/j/98307328424
>
> Full link on the WG21 Calendar and on Mattermost
>
> Agenda will be cleaning up some queued items:
>
> finishing polling on UTF transcoding
>

Assuming you mean p2728r12

- not having an unchecked mode (which of course should never be the
default) leaves some performance on the table, for simd/ branchless
decoding - especially given how.. comprehensive error checking is in this
proposal.
We should discuss that

- as_utfN allows narrowing conversion. I think we should put a lot more
requirements on that,
namely. Preventing as_utfN over charX_t seems like the minimum, but I'm
also concerned about conversion where the underlying type has a different
sizeof.

- I do not understand the motivation for UTF Tags. It seems to try to make
a deduction guide for to_utf_view work - even if we probably don't need one
(use the adaptor objects),
  and I question the ergonomics of trying to use these tags in practice.

- I am not sure I like the contortions around string literals, but I guess
this can be relaxed later.

- reserve_hint() could be specified to return an implementation-defined
value greater or equal to that of the underlying range


> "$ in identifier", and
>

I don't think there is more we could say here, from an SG16 perspective.
rubber-stamp/ship it


>
>
> wg21: TODO [[
> https://github.com/cplusplus/papers/issues/2690][LWG4541]] Unclear
> behavior for parsing locale-dependent format
> :sg16:
>

Having an example would help.


> wg21: TODO [[
> https://github.com/cplusplus/papers/issues/1895][LWG4087]] Standard
> exception messages have unspecified encoding
> :sg16:
>

If we are going to do that, can we also strike the nonsensical first
sentence of the next remark
"The message may be a null-terminated multibyte string (16.3.3.3.4.3
[multibyte.strings] <https://wg21.link/multibyte.strings>), suitable for
conversion and display as a wstring (27.4 [string.classes]
<https://wg21.link/string.classes>, 28.3.4.2.5 [locale.codecvt]
<https://wg21.link/locale.codecvt>)"


> wg21: TODO [[
> https://github.com/cplusplus/papers/issues/1572][LWG2959]]
> char_traits<char16_t>::eof is a valid UTF-16 code unit
> :sg16:
>

We should ask Louis/STL if they are happy to change int_type, or,
alternatively explain LEWG the only solution is to change int_type, and see
if they care.


>
> which are tagged SG16 input wanted.
>
>
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