gistfile1.php

<?php

function module_invoke() {
  $args = func_get_args();
  $module = $args[0];
  $hook = $args[1];
  unset($args[0], $args[1]);
  $function = $module . '_' . $hook;
  if (module_hook($module, $hook)) {
    // debug here
    if($hook == 'update_index') watchdog("debug", $function);
    return call_user_func_array($function, $args);
  }
}