Respond to a custom menu update.
This hook is used to notify modules that a custom menu has been updated. Contributed modules may use the information to perform actions based on the information entered into the menu system.
$menu: An array representing a custom menu:
function hook_menu_update($menu) {
// For example, we track available menus in a variable.
$my_menus = variable_get('my_module_menus', array());
$my_menus[$menu['menu_name']] = $menu['menu_name'];
variable_set('my_module_menus', $my_menus);
}