PHP xml_get_current_byte_index() Function

xml_get_current_byte_index(parser)

<?php
//invalid xml file
$xmlfile = 'test.xml';

$xmlparser = xml_parser_create();

// open a file and read data
$fp = fopen($xmlfile, 'r');
while ($xmldata = fread($fp, 4096))
  {
  // parse the data chunk
  if (!xml_parse($xmlparser,$xmldata,feof($fp)))
    {
    die( print "ERROR: "
    . xml_error_string(xml_get_error_code($xmlparser))
    . "<br />"
    . "Line: "
    . xml_get_current_line_number($xmlparser)
    . "<br />"
    . "Column: "
    . xml_get_current_column_number($xmlparser)
    . "<br />"
    . "Byte Index: "
    . xml_get_current_byte_index($xmlparser)
    . "<br />");
    }
  }

xml_parser_free($xmlparser);
?>

ERROR: Mismatched tag
Line: 5
Column: 41
Byte Index: 72