Cmdlang_cmdliner_runner (cmdlang-cmdliner-runner.Cmdlang_cmdliner

val run : 
  ?exn_handler:(exn -> Err.t option) ->
  unit Cmdlang.Command.t ->
  name:string ->
  version:string ->
  unit

This is the standard way that is designed with cmdlang, assuming you are using Err etc.