{
{   The purpose of this procedure is to process the monitor request to set
{ or get current segment length.  If the segment is shortened, pages beyond
{ new segment length are freed.
{
{        MMP$MTR_SET_GET_SEGMENT_LENGTH (REQUEST_BLOCK)
{
{ REQUEST_BLOCK: (input,output) This parameter contains the monitor function
{        request block for the set or get segment length monitor function.
{
