<?php
$xml = new SimpleXMLElement('<tag></tag>');
echo 'An empty SimpleXMLElement is '.(bool) $xml;
echo "\n";
$xml = new SimpleXMLElement('<tag>data</tag>');
echo 'A SimpleXMLElement with data is '.(bool) $xml;
echo "\n";
$obj = new stdClass();
echo 'An empty stdClass is '.(bool) $obj;