NAME
        CloseDevice - terminates access to the narrator device


   SYNOPSIS
        CloseDevice(IORequest)
                       A1

   FUNCTION
        close invalidates the io_unit and io_device fields in the
        iorequest block, preventing subsequent io until another
        opendevice.  closedevice also reduces the open count.  if
        the count goes to 0 and the expunge bit is set, the device
        is expunged.  If the open count goes to zero and the delayed
        expunge bit is not set, CloseDevice sets the expunge bit.


   INPUTS
        A valid iorequest block with its io_message structure, and
        io_Device and io_Unit fields properly initialized.  These
        fields are initialized by opendevice.


   RESULTS
        CloseDevice invalidates the unit and device pointers in the
        iorequest block.


   SEE ALSO