(PHP 5 >= 5.4.0, PHP 7) Changes the default external entity loader

(PHP 5 >= 5.1.0, PHP 7) Clear libxml error buffer

(PHP 5 >= 5.1.0, PHP 7) Disable libxml errors and allow user to fetch error information as needed

(PHP 5, PHP 7) Set the streams context for the next libxml document load or write

(PHP 5 >= 5.1.0, PHP 7) Retrieve array of errors

(PHP 5 >= 5.1.0, PHP 7) Retrieve last error from libxml

(PHP 5 >= 5.2.11, PHP 7) Disable the ability to load external entities