PROGRAM Rufexample
!
! This program demonstrates the calls necessary for recovery unit journaling.
! It is meant as an example of use in BASIC, it does not implement complete 
! error checking.
!
    EXTERNAL INTEGER FUNCTION SYS$START_RU, SYS$END_RU

!
!   Record structure used for the checking and savings account.
!

    MAP (checking_account) STRING	checking_account_number = 9%, &
		   INTEGER	checking_account_balance, &
		   STRING	fill = 5%

    MAP (savings_account) STRING	savings_account_number = 9%, &
		  INTEGER	savings_account_balance, &
		  STRING	filler = 5%

!
! Open the checking and savings account files.
!
    OPEN "RUF$CHECKING.DAT" FOR INPUT AS FILE 1%, &
		   ORGANIZATION INDEXED, &
		   MAP checking_account

    OPEN "RUF$SAVINGS.DAT" FOR INPUT AS FILE 2%, &
		   ORGANIZATION INDEXED, &
		   MAP savings_account
!
! Recovery unit to initialize savings and checking account files. 
! Note that any I/O errors in this recovery unit will be ignored.
! The checking and savings account will be initialized to $100
! for account "000001234".
!
    Sys_stat% = SYS$START_RU (Recovery_unit_handle BY REF)

    IF ((Sys_stat% and 1% ) = 0%) THEN
	PRINT " Cannot start initialization recovery unit "
	CALL LIB$SIGNAL (Sys_stat%,0,0)
    END IF
!
!   Put $100 dollars in the checking account of "000001234"
!
    checking_account_number = "000001234"
    checking_account_balance= 100%

    WHEN ERROR IN
	 PUT #1
    USE
	 PRINT "Checking account already exists "
    END WHEN
!
!   Put $100 dollars in the savings account of "000001234"
!
    Savings_account_number = "000001234"
    Savings_account_balance= 100%

    WHEN ERROR IN 
	 PUT #2
    USE
	 PRINT "Savings account already exists "
    END WHEN
!
!   End the recovery unit to initialize the checking and savings account
!
    Sys_stat% = SYS$END_RU (Recovery_unit_handle BY REF)

    IF (Sys_stat% and 1% ) = 0% THEN
	PRINT " Cannot end initialization recovery unit "
	CALL LIB$SIGNAL (Sys_stat%, 0, 0)
    END IF

!
! Transfer $10.00 from checking to savings using a recovery unit.
! Note that the recovery unit is aborted if any I/O errors are 
! encountered.
!
    Sys_stat% = SYS$START_RU (Recovery_unit_handle BY REF)

    IF (Sys_stat% and 1% ) = 0% THEN
	PRINT " Cannot start transfer recovery unit "
	CALL LIB$STOP (Sys_stat%)
    END IF
!
! Read the checking account record for "000001234".  Abort recovery unit
! if the operation is not successful.
!
    WHEN ERROR IN 
         GET #1, KEY #0% EQ Checking_account_number
    USE
	 PRINT "Could not find checking account "
	 CALL SYS$ABORT_RU (Recovery_unit_handle BY REF)
    END WHEN
!
! Subtract $10 from the checking account balance.
!
    Checking_account_balance = Checking_account_balance - 10%
!
! Update the checking account file reflecting the new balance.  Abort the 
! recovery unit if the update is not successful.
!
    WHEN ERROR IN 
	 UPDATE #1
    USE
	 PRINT " Cannot update checking account "
	 CALL SYS$ABORT_RU (Recovery_unit_handle BY REF)
    END WHEN


    PRINT 'Pausing for 5 seconds.'
    CALL LIB$WAIT (5)
!
! Read the savings account record for "000001234". Abort recovery unit 
! if the operation is not successful.
!
    WHEN ERROR IN 
         GET #2, KEY #0% EQ Savings_account_number
    USE
	 PRINT " Could not find savings account "
	 CALL SYS$ABORT_RU (Recovery_unit_handle BY REF)
    END WHEN
!
! Add $10 to the savings account.
!
    Savings_account_balance = Savings_account_balance + 10%
!
! Update the savings account file reflecting the new balance.  Abort the 
! recovery unit if the update is not successful.
!
    WHEN ERROR IN 
	UPDATE #2
    USE
	 PRINT " Cannot update savings account "
	 CALL SYS$ABORT_RU (Recovery_unit_handle BY REF)
    END WHEN
!
! End the recovery unit.
!
    Sys_stat% = SYS$END_RU (Recovery_unit_handle BY REF)
    IF (Sys_stat% and 1% ) = 0% THEN
	PRINT " Cannot end transfer recovery unit "
	CALL LIB$STOP (Sys_stat%)
    END IF
!
! Display the new balances.
!
    PRINT "The new checking account balance is $", checking_account_balance
    PRINT "The new savings account balance is $", Savings_account_balance
!
! Close the checking and savings account files.
!
    CLOSE #1
    CLOSE #2

END PROGRAM