objc:objc-object-destroyed

(objc:objc-object-destroyed object)

A generic function called when an objc:standard-objc-object's reference count reaches zero, inside its dealloc. The built-in primary method does nothing; an :after method is the counterpart of implementing dealloc. Until then the Lisp object stays alive: make-instance's reference is the program's to objc:release. Not called by the program. Part of the macOS-only objc package -- the interpreter (java -jar, or the rontolisp native binary), a compiled .class / .jar and a --native executable for macOS on Apple silicon, never a .wasm; on a machine without the runtime it signals an error. See the macOS GUI guide.

MY-APP> (defmethod objc-object-destroyed :after ((object my-object))
          (format t "destroyed ~a~%" (slot-value object 'slot1)))
OBJC-OBJECT-DESTROYED
MY-APP> (release (make-instance 'my-object :slot1 :gone))
destroyed GONE
NIL