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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/114260]
 std::formatter<std::chrono::utc_time<std::chrono::days>> formats as the
 previous day
Date: Thu, 07 Mar 2024 23:08:20 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114260

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Yup, I understand why that's the output. I just thought it seemed off that
something rounded to days didn't land at 00:00:00 and convinced myself that=
 it
should be "corrected". But of course utc_time<days> is not a year_month_day,
it's an exact time point, and it happens to not line up with 00:00:00 for t=
he
reason you gave:

(In reply to Howard Hinnant from comment #2)
> Consequently, 2024-03-05 00:00:00 in utc_time is *not* a multiple of 8640=
0s,
> but rather 27s greater than a multiple of 86400s.  And all
> round<days>(udays) does is round the .time_since_epoch() to the nearest
> multiple of 86400s.  Which in utc_time is 27s earlier, or 2024-03-04
> 23:59:33.

So not a bug then. Thanks for talking me out of introducing a bug here!=