Any-class Object Callbacks

If you add a callback to the MT class with a hook point that begins with *::, such as:

MT->add_callback('*::post_save', 7, $my_plugin, \&code_ref);

then it will be called whenever post_save callbacks are called. “Any-class” callbacks are called after all class-specific callbacks. Note that add_callback must be called on the MT class, not on a subclass of MT::Object.