{------------------------------------------------------------------------------}
{   The purpose of this request is to update the status of all previously
{ initiated MMP$READ and MMP$WRITE requests that have completed but have not
{ yet had the user I/O status block updated with the completion information.
{ This request will be substantially faster than MMP$CHECK_IO_STATUS from both
{ the system and user perspective, because of the use of timestamps to control
{ whether to scan active I/O requests for completions and because the user does
{ not need to specify certain I/O status variables to be checked.
{   The user may specify that the calling task wait a specified amount of time
{ if no I/O requests have completed.
{   This procedure can only be called from ring 6 or below.
{
{   MMP$CHECK_IO_COMPLETIONS (TIMESTAMP, WAIT_TIME, STATUS)
{
{   TIMESTAMP: (input)  This parameter specifies a 'FREE RUNNING CLOCK'
{     value.  If the request specifies a WAIT_TIME and any I/O request has
{     completed since the value of the TIMESTAMP, the wait will be inhibited
{     and control will be returned to the user.
{
{   WAIT_TIME: (input)  This parameter specifies the maximum amount of time the
{     task should wait for an I/O completion.  If the value of this parameter
{     is zero, control will be returned to the user immediately.
{     The wait time is specified in milliseconds.
{
{   STATUS: (output)  This parameter specifies the request status.  Possible
{     error codes are:
{       mme$no_io_active (attempt to wait for I/O, but no I/O active).
{------------------------------------------------------------------------------}
