Unidentify

Unidentify can be used by a transaction scheduler to reverse the effects of the Identify service. Unidentify terminates all APPC services for the transaction scheduler and its subordinate address spaces. Unidentify causes APPC/MVS to shut down the LU or LUs assigned to the transaction scheduler that issued Unidentify. The caller does not have to wait for this to occur. Once the Unidentify request is accepted, APPC/MVS returns control to the caller and assumes responsibility for taking down the LU or LUs. After APPC/MVS returns control, a transaction scheduler may invoke the IXCLEAVE macro to undo the effects of its invocation of Join_Sysappc_Group.

Unidentify automatically disconnects address spaces currently connected to the issuing transaction scheduler. New conversations (that is, inbound or outbound Allocate requests) for the scheduler are rejected. The outcome of existing conversations for the scheduler depends on the type of Unidentify call. (Existing conversations are those for which one LU has successfully sent and its partner LU has successfully received the Allocate request.)

After an Unidentify, the LU is placed in pending state to await another Identify request. A transaction scheduler must issue Identify if it is to restart.

Calls to Unidentify must be issued from the address space that issued the Identify.

Environment

Authorization:

Supervisor state or PSW key 0-7

Dispatchable unit mode:

Task mode

Cross memory mode:

PASN = HASN = SASN

AMODE:

31-bit

ASC mode:

Primary

Interrupt status:

Enabled for I/O and external interrupts

Locks:

Unlocked

Control parameters:

All parameters must be addressable by the caller and in the primary address space.

Format

Figure 1. ATBUID1 - Unidentify

CALL ATBUID1 (Unidentify_type,
               Return_code
             );

Parameters

Unidentify_type

Supplied parameter

Type: Integer
Char Set: N/A
Length: 4 bytes

Specifies the type of Unidentify requested, which affects each LU that is identified with this transaction scheduler. Valid values for this parameter are:

Value

Meaning

0

Unidentify_Normal

Calls to ATBUID1 with an Unidentify_type of Normal (or calls to ATBUNID) cause the ACB for each LU to be closed only after all existing conversations are deallocated. Because work for the LU is quiesced, a normal Unidentify is similar to LUDEL processing.

1

Unidentify_Immediate

Calls to ATBUID1 with an Unidentify_type of Immediate cause the ACB of each LU to be closed immediately. All existing conversations fail when a TP issues the next APPC/MVS or CPI-C service call.

Unidentify_Immediate can be used in situations requiring fast termination, such as takeover by a backup scheduler.

Return_code

Returned parameter

Type: Integer
Char Set: N/A
Length: 32 bits

Unidentify might return one of the following decimal values in the return code parameter:

Decimal: Meaning
0: Unidentify was accepted.
16: The Identify_type value passed on ATBUID1 was not valid.
32: The requested service is not supported in the caller's environment. For example, this return code will be given if the caller invokes any of the transaction scheduler services while holding a lock.
34: The requested transaction scheduler service must be invoked from a transaction scheduler address space.
44: APPC/MVS is not active.
48: APPC/MVS services failure.

Characteristics and Restrictions

Transaction schedulers that call the Unidentify service should not have any enabled unlocked task (EUT) functional recovery routines (FRRs) established. For more information about EUT FRRs, see the information on providing recovery in z/OS MVS Programming: Authorized Assembler Services Guide.