{
{   The purpose  of  this  procedure is to obtain the permanent file root from
{ the active set table.  The set must previously  have  been  located  in  the
{ active  set table.  A permanent file root (SEQ (*)) must be supplied to this
{ routine.
{
{       STP$OBTAIN_AST_PF_ROOT (AST_INDEX, PF_ROOT, STATUS)
{
{ AST_INDEX: (input) This parameter specifies the set for which the  permanent
{       file root is to be obtained.
{
{ PF_ROOT:  (input,  output) This parameter specifies a container in which the
{       permanent file root as stored  in  the  active  set  table  is  to  be
{       returned in.
{
{ STATUS: (output) This parameter returns the request status.
{
{       CONDITIONS: ste$incorrect_root_size
{                   ste$pf_root_not_stored
{
{       IDENTIFIER: stc$set_management_id
{
