::string() <span class="keyword">const</span>;</div><div class="line"><a name="l00247"></a><span class="lineno">  247</span>&#160;</div><div class="line"><a name="l00248"></a><span class="lineno">  248</span>&#160;    <span class="comment">// Does object contain valid point?</span></div><div class="line"><a name="l00249"></a><span class="lineno">  249</span>&#160;    <span class="keywordtype">bool</span> isValid() <span class="keyword">const</span>;</div><div class="line"><a name="l00250"></a><span class="l