}</span>

<span class="special">}}}</span> <span class="comment">// namespaces</span>
</pre>
<p>
        We'll come back to what can go inside the implementation later, but first
        lets look at the user layer. This consists of two overloads of the function,
        with and without a <a class="link" href="../../policy.html" title="Chapter&#160;19.&#160;Policies: Controlling Precision, Error Handling etc">Policy</a> argument:
      </p>
<pre class="programlisting"><span class="keyword">namespace</span>