an class="special">)</span><span class="special">,</span> 
       <span class="keyword">const</span> <span class="identifier">group_compare_type</span><span class="special">&amp;</span> compare <span class="special">=</span> <span class="identifier">group_compare_type</span><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span></pre>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign=