fli:define-foreign-function

(fli:define-foreign-function name (arg*) &key result-type module variadic-num-of-fixed)

The part of LispWorks' fli:define-foreign-function the objc package's examples reach for: defines name as a Lisp function calling the C function foreign-name, which any image loaded in the process may define (libSystem, a framework, a module objc:ensure-objc-initialized or :module loaded). name is lisp-name or (lisp-name foreign-name); a foreign name left out is the Lisp name in lower case with each hyphen an underscore. An argument is (arg-name type) or (:constant value type), the types those objc:invoke's list form takes, converted the same way -- a block goes as objc:objc-at-question-mark. :result-type defaults to :int; an object result is owned when the function's name says it creates or copies (dispatch_queue_create, CFStringCreateCopy), and retained otherwise. :variadic-num-of-fixed makes the arguments past that count variadic. The function runs on the calling thread. Part of the macOS-only fli package, beside objc -- 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 a call signals an error. See the macOS GUI guide.

MY-APP> (fli:define-foreign-function (dispatch-queue-create "dispatch_queue_create")
            ((label objc-c-string) (attributes :pointer))
          :result-type objc-object-pointer)
DISPATCH-QUEUE-CREATE
MY-APP> (fli:define-foreign-function (dispatch-async "dispatch_async")
            ((queue objc-object-pointer) (work objc-at-question-mark))
          :result-type :void)
DISPATCH-ASYNC
MY-APP> (defvar *queue* (dispatch-queue-create "com.example.work" nil))
*QUEUE*