Calculate the days, months and years between 2 dates.

FORM compute_2date_diff.
  DATA: lv_date1 LIKE sy-datum,
        lv_date2 LIKE sy-datum,
        lv_month TYPE pea_scrmm,
        lv_days  TYPE pea_scrdd.
*lv_date1 must be greater than lv_date2
  lv_date1 = '20120201'.
  lv_date2 = '20120101'.
  CALL FUNCTION 'HR_HK_DIFF_BT_2_DATES'
    EXPORTING
      date1                         = lv_date1
      date2                         = lv_date2
     OUTPUT_FORMAT                 = '05'
   IMPORTING
*     YEARS                         =
     months                        = lv_month
     days                          = lv_days
   EXCEPTIONS
     invalid_dates_specified       = 1
     OTHERS                        = 2.
  IF sy-subrc <> 0.
    MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
            WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
  ENDIF.

ENDFORM.                    "compute_2date_diff