diff --git a/includes/module.inc b/includes/module.inc
index 779b668..66c77f5 100644
--- a/includes/module.inc
+++ b/includes/module.inc
@@ -786,10 +786,9 @@ function module_implements_write_cache() {
  * @return
  *   The return value of the hook implementation.
  */
-function module_invoke() {
+function module_invoke($module, $hook) {
   $args = func_get_args();
-  $module = $args[0];
-  $hook = $args[1];
+  // Remove $module and $hook from the arguments.
   unset($args[0], $args[1]);
   if (module_hook($module, $hook)) {
     return call_user_func_array($module . '_' . $hook, $args);
@@ -808,9 +807,9 @@ function module_invoke() {
  *   An array of return values of the hook implementations. If modules return
  *   arrays from their implementations, those are merged into one array.
  */
-function module_invoke_all() {
+function module_invoke_all($hook) {
   $args = func_get_args();
-  $hook = $args[0];
+  // Remove $hook from the arguments.
   unset($args[0]);
   $return = array();
   foreach (module_implements($hook) as $module) {