ENLOTY ( loop, lptype, ifail )
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  Enquire loop type

Receives:
  KI_tag_loop              *loop           --- loop

Returns:
  KI_cod_enlo              *lptype         --- type-code of loop,
                                           --- from range ENLO00
  KI_cod_error             *ifail          --- failure indicator


Description:
  The type of loop is returned as one of the following codes:

      ENLOHO  ---  hole loop
      ENLOPE  ---  peripheral loop
      ENLONA  ---  not applicable

  ENLONA is returned in cases where the distinction between peripheral loops
  and holes does not make sense, for example the end loops of a cylindrical or
  toroidal tube.