<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/80000>80000</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [libc++][shared_mutex] Does we have plan to favor readers over writers?
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          Jolyon0202
      </td>
    </tr>
</table>

<pre>
    libc++'s shared_mutex favor writers over readers, but libstdc++'s shared_mutex favor readers over writers defaultly.

libstdc++‘s shared_mutex use ptread_rwlock_t(PTHREAD_RWLOCK_PREFER_READER_NP  defaultly), and it also support to favor writers over readers.

Official C++ Standard doesn't specify the std::shared_mutex policy. Explanation could be found in original N2406 proposal (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2406.html#shared_mutex_imp) in shared_mutex.

Dose we have plan to favor readers over writers in shared_mutex?
</pre>
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