sig
  val fprintf :
    Pervasives.out_channel -> ('a, Pervasives.out_channel, unit) format -> 'a
  val printf : ('a, Pervasives.out_channel, unit) format -> 'a
  val eprintf : ('a, Pervasives.out_channel, unit) format -> 'a
  val sprintf : ('a, unit, string) format -> 'a
  val bprintf : Buffer.t -> ('a, Buffer.t, unit) format -> 'a
end