<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/74727>74727</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [libc++] Should formatting `year{-99}` with `%C` produce `"-1"` or `"-01"`?
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            libc++
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          StephanTLavavej
      </td>
    </tr>
</table>

<pre>
    [N4964](https://isocpp.org/files/papers/N4964.pdf) \[tab:time.format.spec\]:

> Specifier | Replacement
> --- | ---
> `%C` | The year divided by 100 using floored division. If the result is a single decimal digit, it is prefixed with `0`.

https://github.com/llvm/llvm-project/blob/f1200ca7ac88c6ff9aa4fe3b560cf326dc3d4e25/libcxx/test/std/time/time.syn/formatter.year.pass.cpp#L271-L272

For `year{-99}` and `year{-9}`, this test expects `%C='-1'`, but MSVC's STL emits `%C='-01'`. This Standardese isn't exactly a paragon of crystal clarity, but I think this might be a bug in libc++. (Otherwise, it's a bug in MSVC's STL that we'll need to fix.)
</pre>
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