This topic covers briefly the main CICS® programs that participate in terminal error processing:
CICS controls terminals by using VTAM® (in conjunction with NCP for remote terminals). These communication access methods detect transmission errors between the central processing complex (CPC) and a remote terminal, and automatically invoke error recovery procedures, if specified. These error recovery procedures generally involve:
If the data is not transmitted successfully after the specified number of retries:
For programming information about coding your own NEPs and TEPs, see the CICS Customization Guide and .
You can specify your own processing for VTAM errors in a node error program (NEP). You can use the sample NEP supplied, change the sample, or write your own.
The NEP is entered once for each terminal error; therefore it should be designed to process only one error for each invocation.
In some circumstances, VTAM communication system errors can be passed to an application program. If you issue an EXEC CICS HANDLE command with the TERMERR condition specified, the application program can decide on the action to take in response to the error condition. The TERMERR condition is raised if the DFHZNEP program, if you have one, schedules an ABTASK action (ATNI abend) for a terminal error while the task is attached. It is raised for the current or next terminal control request.
You can specify your own processing for non-VTAM communication errors in a terminal error program (TEP). You can use the sample TEP supplied with CICS (DFHXTEP), change the sample, or write your own.
The TEP is entered once for each terminal error, and therefore should be designed to process only one error for each invocation.
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