Description:
------------
XPath, selecting attribute returns SimpleXMLElement, which's children() method returns NULL.

Probably it's a documentation issue. It says

"Returns a SimpleXMLElement element, whether the node has children or not."


Test script:
---------------
<?php
$s = '<rootNode><childNode attr="attrval" attr2="attr2val">nodeContents</childNode></rootNode>';
$xml = new SimpleXMLElement($s);
$xpathres = $xml->xpath('childNode/@attr');
$xres = array_shift($xpathres);
$xres = array_shift($xml->xpath('childNode/@attr'));
echo '$xres->children() result: ';
var_dump($xres->children());
echo 'typecast result: ';
var_dump((string) $xres);


Expected result:
----------------
$xres->children() result: object(SimpleXMLElement)#2 (0) {
}
typecast result: string(7) "attrval"

Actual result:
--------------
$xres->children() result: NULL
typecast result: string(7) "attrval"