{
{    The purpose of this request is to close a device file.
{ The SDT entry is invalidated. There is no attempt to free the
{ memory associated with the segment or to destroy the file (if
{ a file exists).
{
{   MMP$CLOSE_DEVICE_FILE (segment_number, status)
{
{ SEGMENT_NUMBER: (input) This parameter specifies the segment number
{         of the segment to be closed.
{
{ STATUS: (output) This parameter specifies the status of the request.
{
