signature MLTON_RANDOM =
   sig
      val alphaNumChar: unit -> char
      val alphaNumString: int -> string
      val rand: unit -> word
      val seed: unit -> word option
      val srand: word -> unit
      val useed: unit -> word option
   end

• alphaNumChar ()
  returns a random alphanumeric character.

• alphaNumString n
  returns a string of length n of random alphanumeric characters.

• rand ()
  returns the next pseudo-random number.

• seed ()
  returns a random word from /dev/random. Useful as an arg to srand. If /dev/random can not be read from, seed () returns NONE. A call to seed may block until enough random bits are available.

• srand w
  sets the seed used by rand to w.

• useed ()
  returns a random word from /dev/urandom. Useful as an arg to srand. If /dev/urandom can not be read from, useed () returns NONE. A call to useed will never block -- it will instead return lower quality random bits.