START

The CICS START statement is used to initiate a new transaction asynchronously in a CICS region. Unlike normal transaction flow where a program executes sequentially, START schedules a new transaction to execute in parallel or at a later time.

This command is particularly useful for:

Triggering background processing without delaying the current transaction.
Scheduling transactions to execute at a future time.
Passing data from one transaction to another asynchronously.

Syntax -

EXEC CICS START
     TRANSID('transaction-id')
     [INTERVAL(hhmmss)]
	 [TIME(hhmmss)]
	 [AFTER HOURS(hh) | MINUTES(mm) | SECONDS(ss)]
     [AT HOURS(hh) | MINUTES(mm) | SECONDS(ss)]
     [FROM(data-area)]
     [LENGTH(data-length)]
     [TERMID('terminal-id')]
     [SYSID('system-id')]
     [RTRANSID('transaction-id')]
	 [RTERMID('terminal-id')]
     [RESP(response-field)]
     [RESP2(response-field2)]
     END-EXEC.

TRANSID('transaction-id') - Specifies the transaction ID to be started.
TERMID('terminal-id') - Optional. Specifies the terminal where the transaction should run.
FROM(data-area) - Optional. Specifies a data area (COMMAREA) to pass data to the new transaction.
LENGTH(data-length) - Optional. Defines the length of the COMMAREA.
AT(time) - Schedules the transaction to start at a specific time (HHMMSS format).
AFTER(time) - Optiional. Delays execution by a specified number of minutes.
RTRANSID('transaction-id') - Optional. Specifies the transaction ID to be returned.
SYSID(system-name) - Specifies the system name to which the request is directed.
RESP(response-variable) - Optional. It captures the response code of the START operation and used to check if the command executed successfully or encountered an error.
RESP2(response2-variable) - Optional. It captures the response2 code of the START operation when the error occured.

Short Examples -

Scenario - Starting a Transaction Immediately

...
DATA DIVISION.
WORKING-STORAGE SECTION.
01 WS-TRANS-ID   PIC X(4)  VALUE 'TRN1'. 
01 WS-RESP        PIC S9(4) COMP.

PROCEDURE DIVISION.

    EXEC CICS START
         TRANSID(WS-TRANS-ID)
         RESP(WS-RESP)
         END-EXEC.

    IF WS-RESP = DFHRESP(NORMAL) THEN
       ...
	ELSE
		...
	END-IF.
		 
	...

The transaction ID TRN1 is specified. START initiates the transaction asynchronously. The response code (RESP) is checked to confirm that the operation was successful. The original transaction continues executing without waiting for TRN1 to complete.

Error Conditions -

Eror Condition	RESP	RESP2	Reason
INVREQ	16	4	The value specified in HOURS, for AFTER or AT options, or the hh value specified for INTERVAL, is out of range.
	16	5	The value specified in MINUTES, for AFTER or AT options, or the mm value specified for INTERVAL, is out of range.
	16	6	The value specified in SECONDS, for AFTER or AT options, or the ss value specified for INTERVAL, is out of range.
	16	17	The transaction that has been started by the START operation is not shutdown-enabled, and the CICS region is in the process of shutting down.
IOERR	17		Occurs in any of the following situations: An input/output error occurred during a START operation. A START operation attempts to write to a temporary storage queue when the DFHTEMP data set is full. A START operation uses a REQID name that exists. This condition occurs only when the FROM option is also used.
LENGERR	22		Occurs if LENGTH is not greater than zero.
NOTAUTH	70	7	A resource security check fails on TRANSID (name).
NOTAUTH	70	9	A surrogate user security check fails on USERID (name).
SYSIDERR	53	1	The dynamic routing program rejected the START request.
TERMIDERR	11		Occurs if the terminal identifier in a START command is not defined to CICS.
TRANSIDERR	28		Occurs if the transaction identifier specified in a START command is not defined to CICS.