Description:
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When using the documentation for xml_parse_into_struct to test xml read from a file, the function appears to unsuccessfully parse the data.

The xml file is valid xml, is being read properly and can be dumped by it's fread variable $data.  I can copy and paste the xml into the $data variable and the function will work properly.

The xml_error_string(xml_get_error_code($parser)) is "Empty Document" which is incorrect.

Reproduce code:
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$xml_file = 'someXMLfile.xml';
$filehandler = fopen($xml_file, 'r');
$data = fread($filehandler, filesize($xml_file));
fclose($filehandler);

$parser = xml_parser_create();
xml_parse_into_struct($parser, $data, $vals, $index);
xml_parser_free($parser);

echo "Index array\n";
print_r($index);
echo "\nVals array\n";
print_r($vals);

Expected result:
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Similar results to the documentation for the xml_parse_into_struct() function via print_r().

Actual result:
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Index array Array ( ) Vals array Array ( )