TWAPIP — and application routing failure

For programming information about the EXEC CICS ISSUE PASS command, see ISSUE PASS. The ISSUE PASS command in turn invokes the z/OS Communications Server macro CLSDST with OPTCD=PASS, and, in addition, if NOTIFY has been specified on the CLSDSTP system initialization parameter, with PARMS=(THRDPTY=NOTIFY). CICS is then notified of the outcome of any CLSDST request.

This notification results in an informative message being issued, and causes DFHZNAC to invoke your NEP, whether the CLSDST request has failed or succeeded. The NEP can discover that a CLSDST OPTCD=PASS request is in progress by examining field TWAPFLG for the pass-in-progress indicator, TWAPIP. The success or failure of the CLSDST OPTCD=PASS request can be determined by examining the error code at TWAEC.

If the pass operation fails, DFHZNAC sets up a default set of recovery actions that can be modified by your NEP. A possible recovery, when, for example, the target application program is not active, would be to reestablish the session with the initial application using a SIMLOGON request and for CICS to send its “good morning” message to the terminal. The default action is to leave the session disconnected and to make it NOCREATE.

If CLSDSTP=NONOTIFY has been specified, and autoinstall is being used, CICS takes no action, even if the ISSUE PASS fails.

If persistent sessions support is active, autoinstall terminals are deleted after the AIRDELAY, so any expected NEP processing as a result of CLSDSTP=NOTIFY being coded does not take place.