Declaring class variables question
<p>What do these var declarations actually do inside of a PHP class:</p>

<pre><code>class VbForumsPageMain extends BxDolPageView {
    var $_oMain;
    var $_oTemplate;
    var $_oConfig;
    var $_oDb;

    function VbForumsPageMain(&amp;$oMain) {
        $this-&gt;_oMain = &amp;$oMain;
        $this-&gt;_oTemplate = $oMain-&gt;_oTemplate;
        $this-&gt;_oConfig = $oMain-&gt;_oConfig;
        $this-&gt;_oDb = $oMain-&gt;_oDb;
        parent::BxDolPageView('vb_forums_main');
    }
}
</code></pre>

<p>Are they neccessary and do they add any extra use to the variables?  I'm not sure whey they're in the class twice.</p>
