onst</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="idp162132816"></a><h2>Description</h2>
<p>This specialization of <a class="link" href="optional_last_value.html" title="Class template optional_last_value">signals2::optional_last_value</a> is provided
            to cope with the fact that there is no such thing as an
            <code class="computeroutput">optional&lt;void&gt;</code>, which
            <a clas