Word description Defines an ARM64 variadic callback. The quotation receives the named parameters followed by one borrowed argument cursor. Use the words in alien.varargs to read, copy, or forward its position. All four constructor arguments must be compile-time literals, as for alien-callback.
Notes The C caller determines the anonymous argument types and count. The cursor and its copies expire when the callback exits. Callback execution and error handling follow the ordinary callback rules. A runtime and image built with variadic callback support are required.