Writing IPCS CLISTs

When writing CLISTs that contain TSO/E commands, you must consider the environment in which the CLIST will run when designing the CLIST. This is especially important when designing CLISTs that contain both TSO/E commands and IPCS subcommands.

When you invoke a CLIST from the IPCS dialog, the CLIST can use IPCS subcommands to place information in ISPF function pool dialog variables and can use the ISPEXEC subcommand to request dialog services that use the dialog variables. If TSO/E Release 2 is not installed, ISPF has no knowledge of any CLIST variables used in a CLIST initiated through this panel. Therefore, such CLISTs cannot reference ISPF variables.

Given this flexibility, the functions that can be used in a CLIST are dependent on the environment from which you invoke the CLIST. Before you write the CLIST, decide what environment you will typically invoke the CLIST from. Then review Table 1 for restrictions.

Table 1. Considerations for Designing and Invoking IPCS CLISTs
CLIST Contains:	Invoke as Follows:
IPCS subcommands	In IPCS line mode, batch mode, or through the IPCS dialog
TSO/E commands	In IPCS line mode, batch mode, or through the IPCS dialog with or without the TSO subcommand: Invoke the CLIST with the TSO subcommand if either of the following are true: The CLIST contains a combination of TSO/E authorized commands and functions such as SYSOUTTRAP, and you are invoking the CLIST while in the IPCS dialog One or more TSO/E commands in the CLIST have the same names as IPCS subcommands Invoke the CLIST without the TSO subcommand if the items listed in step 1 are not true.
A combination of IPCS subcommands and TSO/E commands	From IPCS line or batch mode, or through the IPCS dialog, there are three possible ways of invoking such a CLIST: Use the TSO subcommand. If invoked in this way, the IPCS subcommands in the CLIST must be invoked by using the BLSGSCMD dialog program. Invoke the CLIST without using the TSO subcommand. By invoking the CLIST in this way, you do not have to use the BLSGSCMD dialog program to invoke the IPCS subcommands within the CLIST. You can only invoke the CLIST in this way if the CLIST does not contain either of the following: TSO/E commands that have the same names as IPCS subcommands. A combination of TSO/E authorized commands and functions such as SYSOUTTRAP. This rule applies only when you invoke the CLIST from the IPCS dialog. Invoke the CLIST without using the TSO subcommand to invoke the CLIST, but instead using the TSO subcommand within the CLIST to prefix any TSO/E commands. By using this method, you do not have to use the BLSGSCMD dialog program to invoke the IPCS subcommands.
ISPF commands	Invoke the CLIST from the IPCS dialog or through batch mode IPCS if ISPF is active in batch. Do not use the TSO subcommand to invoke the CLIST from the IPCS dialog. The TSO subcommand prevents the CLIST from using ISPF functions.

See z/OS MVS IPCS Customization for the BLSGSCMD dialog program.