client.php

$token = 'xxx';
$domainname = 'http://moodle.localhost';

/// FUNCTION NAME
$functionname = 'local_coursearchive_get_courses_to_update';


$serverurl = $domainname . '/webservice/xmlrpc/server.php'. '?wstoken=' . $token;

$post = '<?xml version="1.0" encoding="iso-8859-1"?><methodCall><methodName>local_coursearchive_get_courses_to_update</methodName></methodCall>';

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL,            $serverurl );
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1 );
curl_setopt($ch, CURLOPT_POST,           1 );
curl_setopt($ch, CURLOPT_POSTFIELDS,     $post );
curl_setopt($ch, CURLOPT_HTTPHEADER,     array('Content-Type: text/xml; charset=utf-8'));

$result=curl_exec ($ch);
print_r($result);