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      <base href="https://bugs.llvm.org/">
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - local static object not Thread safe on Ubuntu 16 clang 3.7"
   href="https://bugs.llvm.org/show_bug.cgi?id=43632">43632</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>local static object not Thread safe on Ubuntu 16 clang 3.7
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>3.7
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>All Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>elia.mirov@gm.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Hi, 

We are using Clang 3.7 with flag -- -std=c++14
We found an issue with Singleton thread safe.

In our code we implemented “Meyers Singleton” as described in 
<a href="https://www.modernescpp.com/index.php/thread-safe-initialization-of-data">https://www.modernescpp.com/index.php/thread-safe-initialization-of-data</a>
This is thread safe implementation guaranteed by std C++ 11 and has by far
better performance according to
<a href="https://www.modernescpp.com/index.php/thread-safe-initialization-of-a-singleton">https://www.modernescpp.com/index.php/thread-safe-initialization-of-a-singleton</a>

However,  this implementation is not thread safe if using libc++ 11
compilation, as we happen to know now, and we had to add a lock_guard to
overcome this issue.</pre>
        </div>
      </p>


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