><span class="special">(</span><span class="identifier">my_expression</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span><span class="special">::</span><span class="identifier">extended</span><span class="special">);</span>
<span class="comment">// e2 a case insensitive POSIX-Extended expression:</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span> <span clas