It returns an error string from the XML parser
Example
<?php
$xmlparser = xml_parser_create();
$fp = fopen(‘test.xml’, ‘r’);
while ($xmldata = fread($fp, 4096)){
if (!xml_parse($xmlparser,$xmldata,feof($fp)))
echo xml_error_string(xml_get_error_code($xmlparser));
}
print_r($xmldata);
xml_parser_free($xmlparser);
?>