{
{   The purpose of this procedure is to determine if a set is active.  This is
{ done by searching the active set table keyed by unique set name.  If the set
{ is  found  in the active set table, the active set table index and a copy of
{ the active set table entry is returned.
{
{       STP$SEARCH_AST_BY_UNIQUE_SET (UNIQUE_SET_KEY, FOUND_AST_ENTRY,
{         FOUND_AST_INDEX, SET_KEY_FOUND)
{
{ UNIQUE_SET_KEY: (input) This parameter specifies the set to search for.
{
{ FOUND_AST_ENTRY:  (output) If set_key_found this parameter returns a copy of
{       the active set table entry for the set.
{
{ FOUND_AST_INDEX: (output) If set_key_found then this parameter  returns  the
{       index into the active set table for the set.
{
{ SET_KEY_FOUND:  (output) This parameter returns whether the set was found in
{       the active set table.
{
