Module Core_kernel__.Unique_id
module type Id = Core_kernel__.Unique_id_intf.Idmodule Int : functor () Id with type t = private Core_kernel__.Import.intAn abstract unique identifier based on ordinary OCaml integers. Be careful, this may easily overflow on 32-bit platforms!
Int63is a safer choice for portability.
module Int63 : functor () Id with type t = private Core_kernel.Int63.tAn abstract unique identifier based on 63 bit integers.