a>
      and <a class="link" href="boost_contract/tutorial.html#boost_contract.tutorial.non_member_functions" title="Non-Member Functions">Non-Member
      Functions</a>):
    </p>
<p>
</p>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">contract</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>

<span class