objc:invoke-with-error

(objc:invoke-with-error class-or-object-pointer method &rest args)

Sends method -- a string or the list form objc:invoke takes, whose name ends in error: or Error: (startAndReturnError:) -- with args followed by an NSError ** it supplies itself. When the result says the call failed (nil, NO or zero) and the method wrote an error, signals objc:ns-error, which holds that NSError; otherwise answers what objc:invoke answers. A method whose name ends in neither is refused. Not in LispWorks, which has no NSError helper. 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> (handler-case (invoke-with-error (invoke "NSFileManager" "defaultManager")
                                         "attributesOfItemAtPath:error:" "/no/such/file")
          (ns-error (e) (list (ns-error-domain e) (ns-error-code e))))
("NSCocoaErrorDomain" 260)
MY-APP> (null (invoke-with-error (invoke "NSFileManager" "defaultManager")
                                 "attributesOfItemAtPath:error:" "/"))
NIL