IDNCEN ( entity, contyp, nentys, ifail )
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  Identify number of connected entities.

    Can be called from the GO.

Receives:
  KI_tag_entity            *entity         --- entity to look in
  KI_cod_ty                *contyp         --- type of desired entities

Returns:
 <KI_int_nitems>           *nentys         --- number of entities found
  KI_cod_error             *ifail          --- failure indicator

Specific errors:
  KI_bad_type_combn         bad type combination
  KI_general_body           general body
  KI_not_a_tag              not an entity

Description:
  IDNCEN is identical to IDCOEN except it only returns the number of connected
  entities.

  The valid combinations of the type 'entity' and 'contyp' can be found by
  examining the table given for the function IDCOEN. In cases where IDCOEN
  may return duplicated items, these will be included in the count; but
  where IDCOEN may return NULTAG this is not counted.

  This function is not supported for general bodies.

  If the given type combination matches a blank cell in the table given with
  IDCOEN, KI_bad_type_combn will be returned in 'ifail'.