OUIDLS ( entys, ids, nids, ifail )
==================================

  Output identifiers of list of entities

    Can be called from the GO.

Receives:
  KI_tag_list_entity       *entys          --- entities whose ids are required

Returns:
  KI_tag_list_int          *ids            --- ids of specified entities
  KI_int_nitems            *nids           --- number of entries in 'ids'
  KI_cod_error             *ifail          --- error code


Description:
  Returns list of identifiers ('ids') corresponding to the given list of
  entities ('entys'), such that the nth entry in 'ids' gives the identifier
  for the nth entry in 'entys'. 'nids' gives the length of list 'ids' (which
  is also the length of list 'entys').

  The entities given in 'entys' need not all belong to the same part. The
  identifiers for any entities which are not attached to a part will be
  returned as zero.

  See OUIDEN for explanation about identifiers.