umber of invocations of <span class="emphasis"><em>f(x)</em></span> to make
              while searching for the root. On exit, this is updated to the actual
              number of invocations performed.
            </p></dd>
</dl>
</div>
<p>
        The final <a class="link" href="../../policy.html" title="Chapter&#160;18.&#160;Policies: Controlling Precision, Error Handling etc">Policy</a> argument is optional and can
        be used to control the behaviour of the function: how it handles errors,
     