`sig
type t
exception Range_error
exception Label_error
val compare : Cf_tai64.t -> Cf_tai64.t -> int
val now : unit -> Cf_tai64.t
val first : Cf_tai64.t
val last : Cf_tai64.t
val to_unix_time : Cf_tai64.t -> float
val of_unix_time : float -> Cf_tai64.t
val to_label : Cf_tai64.t -> string
val of_label : string -> Cf_tai64.t
val add : Cf_tai64.t -> int -> Cf_tai64.t
val add_int32 : Cf_tai64.t -> int32 -> Cf_tai64.t
val add_int64 : Cf_tai64.t -> int64 -> Cf_tai64.t
val sub : Cf_tai64.t -> Cf_tai64.t -> int64
val epoch : Cf_tai64.t
val mjd_epoch : Cf_tai64.t
val leapsec_add : Cf_tai64.t -> bool -> Cf_tai64.t
val leapsec_sub : Cf_tai64.t -> bool * Cf_tai64.t
end`