Input to the Initialization/Termination Program

Figure 1 and Table 1 show the input that MVSSERV makes available to the initialization/termination programs.

When MVSSERV gets control, it invokes your server initialization/termination programs in problem program state, key 8.

As shown in Figure 1, register 1 points to a two-word area. The first word contains the address of the INITTERM control block; the second word contains the address of the CED (connectivity environment descriptor). Of the two:

INITTERM indicates whether the call is for initialization or termination.
The CED is for MVSSERV use only. (If the program issues the DEFSERV, SENDREQ, or CHSTRACE macros, it must pass the CED address.)

Figure 1. Registers Passed at Initialization

You can use the INITTERM mapping macro to obtain input from the INITTERM control block. For details, see INITTERM Macro. Table 1 shows the INITTERM control block with the initialization input.

Table 1. INITTERM Control Block with Initialization Input
Offset Dec(Hex)	Number of Bytes	Field Name	Contents
0(0)	4	INTINIT¹	Initialization or termination indicator. X'00000000' indicates the call is for initialization. X'00000001' indicates termination.
4(4)	4	INTWALEN²	Work area length. Specify the length of a work area that the program can use at termination time.
8(8)	4	INTWAPTR²	Work area address. Specify the address of a work area that the program can use at termination time.
12(C)	16		Reserved
28(1C)	4	INTENVRN	Address of the TSO/E CPPL (command processor parameter list). The CPPL is for system use only; its address must be in register 1 if a server or initialization/termination program invokes a TSO/E command processor or uses TSO/E services such as SCAN or PARSE. For more information about the CPPL, see z/OS TSO/E Programming Guide.
32(20)	4		Reserved

Notes®:

1: Check for initialization or termination indicator.
2: Specify a work area (optional).