Example 1: Check for a record in the file CUSMST that has a key matching the value currently in the field #CUSNUM:
CHECK_FOR IN_FILE(CUSMST) WITH_KEY(#CUSNUM)
IF_STATUS IS_NOT(*EQUALKEY)
ABORT MSGTXT('Customer not found in customer master')
ENDIF
Note how the CHECK_FOR command returns a status of *EQUALKEY or *NOTEQUALKEY, rather than the more commonly used status of *OKAY.
Example 2: Check a nominated tax code against a table of valid tax codes. The first key to the table indicates the tax classification which in this case is always income tax.
CHECK_FOR IN_FILE(TAXTAB) WITH_KEY('INCOME' #TAXCDE)
IF_STATUS IS_NOT(*EQUALKEY)
MESSAGE MSGTXT('Tax code specified not valid for income tax')
ENDIF