GTTGLI ( list, startx, ntags, tags, ifail )
===========================================

  Get values from a list of tags

    Can be called from the GO.

Receives:
  KI_tag_list_<tag>        *list           --- list from which to extract tags
  KI_int_index             *startx         --- position in list from which first
                                           --- tag is to be extracted
  KI_int_nitems            *ntags          --- number of tags to extract
                                           --- from list

Returns:
  KI_tag                    tags[ntags]    --- values extracted from list
  KI_cod_error             *ifail          --- failure indicator

Specific errors:
  KI_list_too_short         'startx' + 'ntags' - 1 is more than list length
  KI_bad_index              'startx' not in range 1 to list length + 1

Description:
  The given values are extracted from the list. The first value is taken from
  the 'startx' position, the second from 'startx' + 1 and so on. The first
  element in the list is number 1.

  GTTGLI does not do any checks on the validity of the tags extracted.