signature MLTON_GC =
   sig
      val collect: unit -> unit
      val pack: unit -> unit
      val setMessages: bool -> unit
      val setSummary: bool -> unit
      val unpack: unit -> unit
   end

• collect ()
  causes a garbage collection to occur.

• pack ()
  shrinks the heap as much as possible so that other processes can use available RAM.

• setMessages b
  controls whether diagnostic messages are printed at the beginning and end of each garbage collection. It is the same as the gc-messages runtime system option.

• setSummary b
  controls whether a summary of garbage collection statistics is printed upon termination of the program. It is the same as the gc-summary runtime system option.

• unpack ()
  resizes a packed heap to the size desired by the runtime.