I'm sure I've done something dumb, but I have the following in a typical custom module, in the .module file, and cannot get it to fire. Yes, I've cleared cache, and no, it's not what I *really* want to do in the hook...I just put the exit there to see it fire, since it wasn't doing anything else I asked it to.
/** * Implements hook_menu_alter() */ function mymodule_menu_alter(&$items) { exit; }