"boost_regex.syntax.basic_extended.h3"></a>
        <span class="phrase"><a name="boost_regex.syntax.basic_extended.anchors"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.anchors">Anchors:</a>
      </h5>
<p>
        A '^' character shall match the start of a line when used as the first character
        of an expression, or the first character of a sub-expression.
      </p>
<p>
        A '$' character shall match the end of a line when used as the last character
  