$FIFOBLK – Manage blocking of a FIFO queue

z/OS JES2 Macros

$FIFOBLK – Manage blocking of a FIFO queue

z/OS JES2 Macros
SA32-0996-00

Use the $FIFOBLK macro to render a queue as not accepting new work (blocking) or to set a queue as now accepting new work (releasing). Blocking is not allowed if the queue is not empty.

Format description


>>-+--------+--$FIFOBLK--QUEUE--=--quehead_addr--quetail_addr--->
   '-symbol-'                                                   

>--,ACTION--=--+-release-+-------------------------------------><
               '-block---'

QUEUE=: Specifies the address of the queue head and tail. The head and tail of the queue must reside in consecutive fullword fields. This parameter is required.
ACTION=: RELEASE or BLOCK. The action can also be specified as a value of 0 (Release) or as a non-zero value (Block). This parameter is required.

Environment

Any.

Registers on entry

R0 - R15:: N/A

Registers on exit

R0 - R13:: Unchanged
R14: Destroyed
R15:: Return code

Return codes

The following return codes (in decimal) are returned in register 15.

Return Code: Meaning
0: Queue was empty before blocking.
4: Queue was not empty, and there is no change made.

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