{
{   The purpose  of this request is to translate a permanent file root locator
{ into a pointer.  This pointer can then be used to reference the pf root.   A
{ base  pointer  (p_vol_set_table)  is  also  provided  from which the segment
{ number is taken.
{
{       STP$BUILD_PF_ROOT_POINTER (PF_ROOT_LOCATOR, P_VOL_SET_TABLE,
{         P_PF_ROOT)
{
{ PF_ROOT_LOCATOR:  (input)  This  parameter specifies the permanent file root
{       locator.   This  must  previously  have  been   constructed   by   the
{       stp$build_pf_root_locator request.
{
{ P_VOL_SET_TABLE:  (input) This parameter specifies the pointer to the volume
{       set table from which the pf_root_locator was obtained.  This parameter
{       is used to get the segment number for the pointer.
{
{ P_PF_ROOT: (output) This parameter returns the pointer to the permanent file
{       root.  This pointer may be returned as NIL, if a NIL pointer was  used
{       to build the locator.
{
