OUUFEN ( tag, ufdval, ifail )
=============================

  Return user field of entity

    Can be called from the GO.

Receives:
  KI_tag                   *tag            --- tag whose user field
                                           --- is required

Returns:
  KI_int_ufdval             ufdval[]       --- user-field value -
                                           --- array length is the user-field
                                           --- size set by STAMOD
  KI_cod_error             *ifail          --- error code

Specific errors:
  KI_not_a_tag              'tag' is not valid
  KI_no_user_fields         user fields are not in use

Description:
  The user-field value for 'tag' is returned in array 'ufdval'.

  If the user field has not been set explicitly by calling SEUFEN,
  each element of array 'ufdval' will be zero.