Issuing a SETLOGON macroinstruction

An LU 6.2 program must issue the SETLOGON OPTCD=START macroinstruction before VTAM® can activate any sessions managed by VTAM. Session activation can be initiated, but not completed, until the SETLOGON is issued. Therefore, session activations that are initiated as a result of APPCCMD CONTROL=CNOS, CONTROL=ALLOC, or CONTROL=PREALLOC macroinstructions are queued until the SETLOGON is issued. The APPCCMD does not complete while the activation is queued.

Table 1 summarizes how SETLOGON OPTCD=START affects session initiation.

Table 1. Impact of SETLOGON on session establishment
Application's Capability	Before SETLOGON OPTCD=START	After SETLOGON OPTCD=START
For the establishment of sessions initiated by VTAM to satisfy conversation requests.	All CINITs are queued.	CINITs either: Schedule the LOGON exit. If a LOGON exit has not been provided, then they are accepted by VTAM for the application program if the application has specified APPC=YES and this is an LU 6.2 session.

The SETLOGON macroinstruction is also used to control other characteristics of an application program. Two types of the SETLOGON macroinstruction, OPTCD=PERSIST and OPTCD=NPERSIST, permit the persistent LU-LU session function to be dynamically enabled and disabled. The PERSIST option enables VTAM to retain modes and any associated sessions when an application program fails. The NPERSIST option disables that capability. In addition, a timer can be specified with the PERSIST option to control the maximum amount of time that can elapse between a failure and a recovery.

The SETLOGON macroinstruction with OPTCD=GNAMEADD and OPTCD=GNAMEDEL may be used in a sysplex environment to allow an application to support a generic resource name. For more information about the generic resources function, refer to z/OS Communications Server: SNA Network Implementation Guide.

Refer to z/OS Communications Server: SNA Programming for detailed information on the SETLOGON macroinstruction.