allback provided to <a class="el" href="../../da/d87/fftools__thread__queue_8h.html#a7c344c91be2c77f54a4b23a7fbe03497">tq_alloc()</a> </td></tr>
  </table>
  </dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd><ul>
<li>0 a data item was successfully read; *stream_idx contains a non-negative stream index</li>
<li>AVERROR_EOF When *stream_idx is non-negative, this signals that the sending side has marked the given stream as finished. This will happen at most once for each stream. When *stream_idx is -1