"special">,</span> 
                     <span class="identifier">DefaultT</span> <span class="keyword">const</span> <span class="special">&amp;</span> def_val<span class="special">)</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="idp92500096"></a><h2>Description</h2>
<p>The function extracts an attribute value from the view. The user has to explicitly specify the type or set of possible types of the attribute value to be extracted.</p>
<div class="note"><table border="0" su