8221;</a> for details.
The <code class="literal">ref</code> and <code class="literal">cref</code> functions are
general purpose utility functions in Boost, and hence defined directly
in the <code class="literal">boost</code> namespace.

</p>
</li>
<li class="listitem"><p>
Array types cannot be copied, they are thus stored as const reference by default.
</p></li>
<li class="listitem">
<p> 
For some expressions it makes more sense to store the arguments as references. 

For example, the obvious intention of t