recast the interface function to deliver the first
          <span class="emphasis"><em>successful</em></span> result.
        </p>
<p>
          That does beg the question: what if <span class="emphasis"><em>all</em></span> the task functions
          throw an exception? In that case we'd probably better know about it.
        </p>
<p>
          <a name="exception_list"></a>The <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4407.html#parallel.exceptions.synopsis" target="_top">C++
     