fli:pointerp
(fli:pointerp object)
True when object is a foreign pointer: what fli:allocate-foreign-object and fli:make-pointer answer, and every pointer objc:invoke or a callback receives. Not an ffi: pointer. 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. See the macOS GUI guide.
CL-USER> (fli:pointerp (objc:invoke (objc:data "abc") "bytes"))
T