Session management data area

This function allows an exit to pass a pointer of a model piece of storage (session management data area), with a descriptive header, back to VTAM® on any session-related exit invocation. VTAM copies, maintains, and passes back the storage on each subsequent exit call for that session. Each session can have a session management data area.

The exit can change or update the VTAM copy of the storage when it is passed and, if it does, VTAM maintains the changed copy. The session management data area is freed automatically after initial accounting. Alternatively, if the exit indicates to VTAM that it wants the data area to remain allocated, the data area is held by VTAM until final accounting is completed.

The parameter list for the SME routine includes a session management data address at offset X'4C' for all functions except begin, exit replacement, exit replaced, and end. The parameter list is shown in Table 1.

Table 1. Session management data area parameter list
Dec (Hex) Offset	Size (Bytes)	Description
0 (0)	2	Total length of the variable data including this length field
2 (2)	1	Exit data flags B'1... ....' To be set to 1 by the exit if the data is to be retained until Final Accounting. If it is not set by the exit, the data will be freed after the Initial Accounting call. B'.111 1111' Reserved for future use
3 (3)	*	Variable length data (2037 bytes maximum)

The size of the session-related storage is limited to 2040 (X'7F8') bytes. If this size is exceeded, the storage is not allocated, and a null (0) pointer is passed on subsequent exit invocations for this session.

A pointer to the exit's copy of storage can be passed to VTAM on return from any valid session-related invocation when the parameter list pointer at X'4C' is zero and when the exit is first invoked.

VTAM does not maintain a data area for CLSDST PASS (Initiate Other CD) or Directed Search List (DSRLST) processing.

If succeeding exit calls return different sizes for a particular session or if an exit returns a pointer to different storage, all VTAM storage is freed and a null pointer (0) is passed on subsequent exit invocations for the related session.