{
{   The purpose of this request is to find a file description sub-record
{ within an info record and return a pointer to it.
{
{       PFP$FIND_FILE_DESCRIPTION (P_INFO_RECORD, P_FILE_DESCRIPTION, STATUS)
{
{ P_INFO_RECORD: (input) This parameter specifies the info record in which
{       the file description sub-record is to be found.
{
{ P_FILE_DESCRIPTION: (output) This parameter returns a pointer to the desired
{       file description.
{
{ STATUS: (output) This parameter returns the request status.
{
{        CONDITIONS: pfe$unknown_file_description
{                    pfe$bad_info_record_format
{
