The variable exit doesn't work

Hi,All

i have create a exit type variable and assign to a query as filter.

and in CMOD add code to program: EXIT_SAPLRRS0_001

But the exit doesn't work , i set break-point but it doesn't stop at all.

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CASE I_VNAM.

WHEN 'ZFISYEAREXIT1'.

READ TABLE I_T_VAR_RANGE INTO L_S_VAR_RANGE WITH KEY VNAM = 'ZFISYEAREXIT1'.

IF SY-SUBRC = 0.

CLEAR L_S_RANGE.

L_S_RANGE-LOW = sy-datum(4). "low value, for example, 2007

L_S_RANGE-HIGH = sy-datum(4). "high value = input

L_S_RANGE-SIGN = 'I'.

L_S_RANGE-OPT = 'BT'.

APPEND L_S_RANGE TO E_T_RANGE.

ENDIF.

ENDCASE.