<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/97601>97601</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [libc++] No library support for `char8_t` if compiled without C++20 but with `-fchar8_t`
        </td>
    </tr>

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

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

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

<pre>
    Currently, `_LIBCPP_HAS_NO_CHAR8_T` is always defined if not compiled with `-std=c++20` or above:

https://github.com/llvm/llvm-project/blob/3ab2247d10673419609333a33bca0eca8a56bf3d/libcxx/include/__config#L702-L704

But both Clang and GCC allow `char8_t` in older standards with the `-fchar8_t` flag: https://godbolt.org/z/ePcrqvWsa

Someone specifying `-fchar8_t` presumably is going to use `char8_t` consistently even before C++20, so it makes sense to allow using library facilities for `char8_t`. One problem I can think of is that some names (like `u8string`) aren't reserved in C++17, but someone using `-fchar8_t` should know not to use them. Plus libstdc++ supports it.

</pre>
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