<html>
    <head>
      <base href="http://llvm.org/bugs/" />
    </head>
    <body><span class="vcard"><a class="email" href="mailto:mclow.lists@gmail.com" title="Marshall Clow (home) <mclow.lists@gmail.com>"> <span class="fn">Marshall Clow (home)</span></a>
</span> changed
              <a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED INVALID - libc++ std::ostrstream leaks memory."
   href="http://llvm.org/bugs/show_bug.cgi?id=22021">bug 22021</a>
        <br>
             <table border="1" cellspacing="0" cellpadding="8">
          <tr>
            <th>What</th>
            <th>Removed</th>
            <th>Added</th>
          </tr>

         <tr>
           <td style="text-align:right;">Status</td>
           <td>NEW
           </td>
           <td>RESOLVED
           </td>
         </tr>

         <tr>
           <td style="text-align:right;">Resolution</td>
           <td>---
           </td>
           <td>INVALID
           </td>
         </tr></table>
      <p>
        <div>
            <b><a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED INVALID - libc++ std::ostrstream leaks memory."
   href="http://llvm.org/bugs/show_bug.cgi?id=22021#c1">Comment # 1</a>
              on <a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED INVALID - libc++ std::ostrstream leaks memory."
   href="http://llvm.org/bugs/show_bug.cgi?id=22021">bug 22021</a>
              from <span class="vcard"><a class="email" href="mailto:mclow.lists@gmail.com" title="Marshall Clow (home) <mclow.lists@gmail.com>"> <span class="fn">Marshall Clow (home)</span></a>
</span></b>
        <pre>This is a "required" memory leak (if you can believe that).

When you call strstreambuf::str() (which ostrstream is derived from), you get a
pointer to its internal buffer, and the stream is "frozen" (see
depr.strstreambuf.members/2 in the standard). Note that in spite of the method
being named "str", it does NOT return a std::string.

When the stream is destructed, the buffer may not be freed if the stream is
"frozen".
(see depr.strstreambuf.cons/8). 

If you rewrite your code thus:

    static std::string MessageComposer( uint32_t index )
    {
    std::ostrstream stm;
    stm << "This is message #" << index << "." << std::endl;
    std::string foo = stm.str();
    stm.freeze(false);
    return foo;
    }

you will see that the "leak" has disappeared.
(Yeah, it's easy to misuse this object. Maybe that's why it is deprecated)</pre>
        </div>
      </p>
      <hr>
      <span>You are receiving this mail because:</span>
      
      <ul>
          <li>You are on the CC list for the bug.</li>
      </ul>
    </body>
</html>