ssage returns.</dd></dl>
<dl class="section warning"><dt>Warning</dt><dd>If you re-use message handler code between subscriptions with and without timeouts, keep in mind that the message passed in the message handler may be <code>NULL</code>.</dd></dl>
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramname">sub</td><td>the location where to store the pointer to the newly created <a class="el" href="group__types_group.html#ga87158ec63b4f90f69e20451624ea01d8" title="I