singleton example

    public static function Dsingleton(
        $package, $msgCallback = false, $contextCallback = false,
        $throwPEAR_Error = false, $stackClass = 'PEAR_ErrorStack'
    ) {
        if (isset($GLOBALS['_PEAR_ERRORSTACK_SINGLETON'][$package])) {
            return $GLOBALS['_PEAR_ERRORSTACK_SINGLETON'][$package];
        }
        if (!class_exists($stackClass)) {
            if (function_exists('debug_backtrace')) {
                $trace = debug_backtrace();
            }
            PEAR_ErrorStack::staticPush('PEAR_ErrorStack', PEAR_ERRORSTACK_ERR_NONCLASS,