Enqueue domain functions, The enqueue function – IBM SC33-1683-02 User Manual

Page 350

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Notes:

1. For more detail, refer to the explanation of RESPONSE and REASON in

“General form of an XPI call” on page 286.

2. ‘NOT_OPEN’ means that the CICS dump data set is closed.

3. ‘OPEN_ERROR’ means that an error occurred while a CICS dump data set was

being opened.

4. ‘PARTIAL’ means that the transaction dump resulting from this request is

incomplete.

Enqueue domain functions

There are two XPI enqueue domain functions. These are the DFHNQEDX macro
calls ENQUEUE and DEQUEUE.

The ENQUEUE function

The ENQUEUE functions is provided on the DFHNQEDX macro call. It allows you
to enqueue on a named resource.

ENQUEUE

DFHNQEDX [CALL,]

[CLEAR,

[IN,

FUNCTION(ENQUEUE),

ENQUEUE_NAME1(address,length),

[ENQUEUE_NAME2(address,length),]

MAX_LIFETIME(DISPATCHER_TASK),

[WAIT(YES|NO),]

[PURGEABLE(YES|NO),]

[OUT,

ENQUEUE_TOKEN,

DUPLICATE_REQUEST,

RESPONSE (name1 | *),

REASON(name1 | *)]

DUPLICATE_REQUEST

indicates that the requesting dispatcher task already owns the resource being
enqueued.

ENQUEUE_NAME1(address,length)

specifies the high-order part of name to be enqueued.

ENQUEUE_NAME2(address,length)

specifies the low-order part, if any, of name to be enqueued.

ENQUEUE_TOKEN

enables a subsequent DEQUEUE request to identify the resource by a token
rather than enqueue name, allowing the NQ domain to locate the enqueue
control block directly, and hence more efficiently.

MAX_LIFETIME(DISPATCHER_TASK)

MAX_LIFETIME(DISPATCHER_TASK) is required and specifies that all XPI
enqueues are owned by the requesting dispatcher task.

If you use the ENQUEUE XPI call to ensure that your global user exit progams
are threadsafe, you are recommended to free (dequeue) resources during the
invocation of the global user exit program in which they were enqueued.

dump control functions

318

CICS TS for OS/390: CICS Customization Guide

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