CLONE(5)                                                 CLONE(5)

          clone - duplicate a fid

          Tclone  tag[2] fid[2] newfid[2]
          Rclone  tag[2] fid[2]

          The clone request carries as arguments an existing fid and a
          proposed newfid (which must not be in use) that the client
          wishes to associate with the same file as fid. The fid must
          be valid in the current session and must not have been
          opened for I/O by an open or create message.  After a suc-
          cessful clone and before any subsequent messages, fid and
          newfid are indistinguishable.

          A clone message is generated by any system call that evalu-
          ates a path name and by a read of a union directory.