Writing a task-related user exit program
The main function of the task-related user exit program is to translate the calling program's parameters into a form acceptable to your non-CICS® resource manager, and then to pass control to the resource manager. This section describes the user exit parameter lists, the schedule flag word used by the exit program to register its need to be invoked by CICS management services, and register-handling in the task-related user exit program. This section also discusses the use of the CICS syncpoint manager and the CICS task manager. It also discusses some factors that you should consider if you plan to use TCBs provided by the CICS open transaction environment (OTE).
About this task
Recursion within a task-related user exit program is possible. The task-related user exit can invoke itself recursively. It can do this, for example, by issuing a DFHRMCAL call to its own entry name (as specified on the EXEC CICS ENABLE command). It can also be entered recursively if it performs an EXEC CICS SYNCPOINT when it is interested in SYNCPOINT invocations.
Task-related user exit programs cannot access channels and containers created by application programs. They can, however, create their own channels and pass them to programs which they call. For information about channels and containers, see Transferring data between programs using channels.
The calling program's parameters are described in Caller parameter lists.
CICS-supplied procedures for TRUEs
When you write a TRUE program, you need to use the DFHEITAL procedure to translate, assemble, and link edit the load modules. The procedure is available as part of the SDFHPROC library. For more information about using the CICS-supplied procedures see, Using the CIS-supplied procedures to install application programs.