TT> though sometimes it is
useful on its own. 

<p>
The <tt>DFSVisitor</tt> supplied by the user determines what
actions are taken at each event-point within the algorithm.

<p>
The <tt>ColorMap</tt> is used by the algorithm to keep track
of which vertices have been visited.

<p>The second variant can be used, for example, to find all marked vertices
reachable from a start vertex by a path which does not contain any another
marked vertices.


<P>

<h3>Where Defined:</h3>

<a href="../../../boost/graph/depth