OS.Utype !'a result = ('a, [ `Unix of Unix.error ]) resultval pp_error : Format.formatter -> [ `Unix of Unix.error ] -> unitval open_error : 'a result -> ('a, [> `Unix of Unix.error ]) resultval error_to_msg : 'a result -> ('a, [> Rresult.R.msg ]) resultval call : ('a -> 'b) -> 'a -> 'b resultval mkdir : Fpath.t -> Unix.file_perm -> unit resultval stat : Fpath.t -> Unix.stats resultval lstat : Fpath.t -> Unix.stats result