Chapter 9. Writing A Node Error Program - IBM SC34-6814-04 Customization Manual

Chapter 9. Writing a node error program

Considerations common to all user-replaceable programs
Note that the comments contained in Chapter 5, "General notes about
user-replaceable programs," on page 435 apply to this chapter.
This chapter contains information about the node error program (NEP) of CICS
Transaction Server for z/OS, Version 3 Release 2. Node error programs, not
terminal error programs, must be used for terminals and logical units supported via
the ACF/VTAM interface.
The chapter is divided into the following sections:
1. "Background to CICS-VTAM error handling" on page 480 is an overview. If you
2. "When an abnormal condition occurs" on page 486 describes the CICS
3. "The sample node error program" on page 496 describes the CICS-supplied
4. "Writing your own node error program" on page 505 discusses the factors you
5. "Using the node error program with XRF or persistent sessions" on page 510.
Note:
© Copyright IBM Corp. 1977, 2011
are not familiar with the node error program, you should read this section. If you
are familiar with NEPs, you may be able to go straight to the detailed
information in the following sections, and look at the subjects that particularly
interest you.
components that are invoked when an abnormal condition is detected from a
VTAM logical unit.
sample NEP.
need to consider when writing your own node error program.
1. Like the terminal error program for non-VTAM devices, the node error
program for VTAM-attached terminals is available in three forms:
a. The default node error program
b. The CICS-supplied sample node error program
c. User-written versions.
All three types are discussed in the following sections.
2. In this chapter, "VTAM 3270" refers to a non-SNA 3270 connected
through VTAM, and "3270 compatibility mode" refers to an SNA 3270
connected through VTAM.
3. If you code an EXEC CICS HANDLE CONDITION TERMERR command
in your application program, it is sometimes possible for the application
program to handle exceptional cases, rather than using a node error
program. The 'TERMERR' condition is driven if the node abnormal
condition program (DFHZNAC) actions an ABTASK ('ATNI' abend). Note
that 'TERMERR' is application-related, and is not an alternative to the
node error program, which must be used for session-related problems.
Dealing with errors in the application program is particularly useful in an
intersystem communication (ISC) environment. For further information,
refer to ISC and IPIC intercommunications facilities, in the CICS
Intercommunication Guide.
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