{
{ Procedure DUP$OPEN_DISPLAY is the central interface in DEBUG for opening
{ output files.
{
{ DUP$OPEN_DISPLAY (file_name: fst$file_reference;
{      VAR display_control_pointer: ^clt$display_control;
{      VAR status: ost$status)
{
{ file_name - the file to which the users output is destined
{
{ display_control_pointer - a pointer to a record where NOSVE stores information
{      about the file for this instance of open
{
{ status - conventional status variable
{
{ If the filename is that of the current default DEBUG output file, the users
{ display_control_pointer is modified to point to the display_control record
{ owned by this procedure which describes the default DEBUG output file.
{ DUP$OPEN_DISPLAY will return a bad status if an open is unsuccessful.
{
