Description:
------------
---
From manual page: http://www.php.net/function.simplexml-load-string
---

The `simplexml_load_string` function returns a SimpleXML object or FALSE. However under certain conditions it may return a SimpleXML object that resolves as FALSE, complicating error handling. Spcifically, this happens when all elements in the document are namespaced, resulting in no publicly visible state in the SimpleXML object.

The documentation should be updated with a warning similar to that for `strpos` that when checking for failure, the output must be compared to FALSE with === instead of simply resolved using PHP's casting rules.

Test script:
---------------
<?php

$xml = <<<XML
<?xml version="1.0" encoding="UTF-8"?>
<ns1:Root xmlns:ns1="http://example.com/custom">
<ns1:Node>There's stuff here</ns1:Node>
</ns1:Root>
XML;

$simplexml = simplexml_load_string($xml);

// This prints "Parse Error".
echo ($simplexml ? 'Valid XML' : 'Parse Error'), PHP_EOL;

// But this prints "There's stuff here", proving that
// the SimpleXML object was created successfully.
echo $simplexml->children('http://example.com/custom')->Node, PHP_EOL;

// The documentation should instruct us to use this instead:
echo ($simplexml !== FALSE ? 'Valid XML' : 'Parse Error'), PHP_EOL;


Expected result:
----------------
Valid XML
There's stuff here
Valid XML

Actual result:
--------------
Parse Error
There's stuff here
Valid XML