Cleanup session

For certain types of session outages, see Session outage notification (SON) codes on UNBIND. VTAM® sends the application program a CLEANUP request unit.

Arrival of the CLEANUP request unit at an application program causes the program's NSEXIT exit routine to be scheduled (if one exists). Because VTAM has completely terminated the session, the exit routine does not take any action to end the session (that is, it does not issue a CLSDST or TERMSESS macroinstruction). The exit routine can clean up application program control blocks for the session. The exit routine can also attempt to reestablish the session, and the attempt can be successful if the cause of the session outage has been repaired or bypassed, and the desired LU is available. The format of the CLEANUP request unit is shown in Figure 1.

Figure 1. Format of a Cleanup Session request unit

The diagram shows the format of a Cleanup Session request unit.

If a PLU application program does not have an SCIP exit routine or has SONSCIP=NO coded on its APPL definition statement, any UNBIND it receives is converted to a CLEANUP for processing by the NSEXIT exit routine.

When the application program involved in a disrupted session is acting as the PLU and does not have an NSEXIT exit routine, that program's LOSTERM exit routine (if one exists) can be scheduled to report loss of the session. See Session outage notification. An application program acting as an SLU must have an NSEXIT exit routine or else it receives no notification of sessions being cleaned up.

Even if no other action is taken, the NSEXIT exit routine should set registers 0 and 15 to 0 before returning to VTAM.

Table 1. NSEXIT exit routine: Registers upon entry
Reg	Contents
0, 2-13	Unpredictable
1	Address of a parameter list that includes the following: Word 1—address of ACB for application program to which the network services RU is sent Word 2—contents depend on the type of RU: CLEANUP RU - CID of the session NSPE or Notify (control vector hex 3) RU - reserved. Word 3—contents depend on the type of RU: CLEANUP RU - USERFLD data of NIB when the session referred to by the CID is established (using OPNDST or OPNSEC) NSPE - reserved Notify RU - USERFLD field contents of NIB associated with the issued SIMLOGON, REQSESS, or CLSDST OPTCD=PASS. If another exit has already been scheduled reporting this failure, this word can be zero. Words 4, 6—reserved Word 5—address of a VTAM-supplied, read-only RPL that resides in read-only VTAM storage and that cannot be used by RPL-based macroinstructions. Word 7—contents depend on the type of RU: CLEANUP or NSPE RU - reserved NOTIFY RU - address of network identifier parameter list ¹
14	VTAM address that is branched to when NSEXIT exit routine completes processing
15	Address of NSEXIT exit routine
Note: The network identifier parameter list is mapped by the ISTNRIPL DSECT. For more information, see Table 1.