in BAPI_Material_saveData Error

I'm facing a problem for uploading the material through bapi BAPI_Material_SaveData.

BAPI_MARC1-PLANT = IT_DATA-WERKS.

BAPI_MARC1-PUR_GROUP = IT_DATA-EKGRP.

"BAPI_MARC1-AVAILCHECK = 'X'.

BAPI_MARCX-PLANT = IT_DATA-WERKS.

BAPI_MARCX-PUR_GROUP = 'X'.

"BAPI_MARCX-AVAILCHECK = 'X'.

is BAPI_MARC-AvailCheck fileld is mandatory or not. ?

Regards,

Masoom Ali