def ipc_set(shmid_ds)
      unless Shmid_ds === shmid_ds
	raise ArgumentError,
	  "argument to ipc_set must be a Shmid_ds"
      end
      check_result(shmctl(@shmid, IPC_SET, shmid_ds))
    end
def ipc_set(shmid_ds)
      unless Shmid_ds === shmid_ds
	raise ArgumentError,
	  "argument to ipc_set must be a Shmid_ds"
      end
      check_result(shmctl(@shmid, IPC_SET, shmid_ds))
    end
Set the Shmid_ds object. See shmctl(2).