(PHP 5)
libxml_set_streams_context — Set the streams context for the next libxml document load or write
$streams_context
   )Sets the streams context for the next libxml document load or write.
No value is returned.
Example #1 A libxml_set_streams_context() example
<?php
$opts = array(
    'http' => array(
        'user_agent' => 'PHP libxml agent',
    )
);
$context = stream_context_create($opts);
libxml_set_streams_context($context);
// request a file through HTTP
$doc = DOMDocument::load('http://www.example.com/file.xml');
?>