この例は、簡単な libxml エラーハンドラを構築する方法を示すものです。
    
<?php
libxml_use_internal_errors(true);
$xmlstr = <<< XML
<?xml version='1.0' standalone='yes'?>
<movies>
 <movie>
  <titles>PHP: Behind the Parser</title>
 </movie>
</movies>
XML;
$doc = simplexml_load_string($xmlstr);
$xml = explode("\n", $xmlstr);
if ($doc === false) {
    $errors = libxml_get_errors();
    foreach ($errors as $error) {
        echo display_xml_error($error, $xml);
    }
    libxml_clear_errors();
}
function display_xml_error($error, $xml)
{
    $return  = $xml[$error->line - 1] . "\n";
    $return .= str_repeat('-', $error->column) . "^\n";
    switch ($error->level) {
        case LIBXML_ERR_WARNING:
            $return .= "Warning $error->code: ";
            break;
         case LIBXML_ERR_ERROR:
            $return .= "Error $error->code: ";
            break;
        case LIBXML_ERR_FATAL:
            $return .= "Fatal Error $error->code: ";
            break;
    }
    $return .= trim($error->message) .
               "\n  Line: $error->line" .
               "\n  Column: $error->column";
    if ($error->file) {
        $return .= "\n  File: $error->file";
    }
    return "$return\n\n--------------------------------------------\n\n";
}
?>
     
    
<titles>PHP: Behind the Parser</title>
----------------------------------------------^
Fatal Error 76: Opening and ending tag mismatch: titles line 4 and title
  Line: 4
  Column: 46
--------------------------------------------