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  29 <h2><span class="refentrytitle">Class optional_last_value&lt;void&gt;</span></h2>
  30 <p>boost::signals2::optional_last_value&lt;void&gt; &#8212; Evaluate an InputIterator sequence.</p>
  31 </div>
  32 <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
  33 <div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../../signals2/reference.html#header.boost.signals2.optional_last_value_hpp" title="Header &lt;boost/signals2/optional_last_value.hpp&gt;">boost/signals2/optional_last_value.hpp</a>&gt;
  34
  35 </span>
  36 <span class="keyword">class</span> <a class="link" href="optional_last_idp719737328.html" title="Class optional_last_value&lt;void&gt;">optional_last_value</a><span class="special">&lt;</span><span class="keyword">void</span><span class="special">&gt;</span> <span class="special">{</span>
  37 <span class="keyword">public</span><span class="special">:</span>
  38   <span class="comment">// types</span>
  39   <span class="keyword">typedef</span> <span class="keyword">void</span> <a name="boost.signals2.optional_last_idp719737328.result_type"></a><span class="identifier">result_type</span><span class="special">;</span>
  40
  41   <span class="comment">// <a class="link" href="optional_last_idp719737328.html#idp719744736-bb">invocation</a></span>
  42   <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <a class="link" href="../../InputIterator.html" title="Concept InputIterator">InputIterator</a><span class="special">&gt;</span>
  43     <span class="identifier">result_type</span> <a class="link" href="optional_last_idp719737328.html#idp719745296-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="identifier">InputIterator</span><span class="special">,</span> <span class="identifier">InputIterator</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  44 <span class="special">}</span><span class="special">;</span></pre></div>
  45 <div class="refsect1">
  46 <a name="idp522997216"></a><h2>Description</h2>
  47 <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
  48             to cope with the fact that there is no such thing as an
  49             <code class="computeroutput">optional&lt;void&gt;</code>, which
  50             <a class="link" href="optional_last_value.html" title="Class template optional_last_value">optional_last_value</a> would otherwise try to
  51             use as its <code class="computeroutput">result_type</code>.  This specialization
  52             instead sets the <code class="computeroutput">result_type</code> to be <code class="computeroutput">void</code>.
  53           </p>
  54 <div class="refsect2">
  55 <a name="idp523002992"></a><h3>
  56 <a name="idp719744736-bb"></a><code class="computeroutput">optional_last_value</code> invocation</h3>
  57 <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
  58 <pre class="literallayout"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <a class="link" href="../../InputIterator.html" title="Concept InputIterator">InputIterator</a><span class="special">&gt;</span>
  59   <span class="identifier">result_type</span> <a name="idp719745296-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="identifier">InputIterator</span> first<span class="special">,</span> <span class="identifier">InputIterator</span> last<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
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  61 <colgroup>
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  63 <col>
  64 </colgroup>
  65 <tbody><tr>
  66 <td><p><span class="term">Effects:</span></p></td>
  67 <td><p>Attempts to dereference every iterator in the sequence <code class="computeroutput">[first, last)</code>.
  68               </p></td>
  69 </tr></tbody>
  70 </table></div>
  71 </li></ol></div>
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  77 <td align="right"><div class="copyright-footer">Copyright &#169; 2001-2004 Douglas Gregor<br>Copyright &#169; 2007-2009 Frank Mori Hess<p>Distributed under the Boost
  78     Software License, Version 1.0. (See accompanying file
  79     <code class="filename">LICENSE_1_0.txt</code> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</p>
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