READQ TD

The READQ TD command takes records off a transient data queue, one at a time, in order. It is the "receive" side: triggered print tasks and message processors live on this command.

Syntax and options

• QUEUE or QNAME - the symbolic destination name of the TD queue.
• INTO - the data area where CICS puts the record.
• LENGTH - a field that CICS sets to the actual length of the record read.
• There is no ITEM and no NEXT option: TD reads are always sequential, always the next record.

Destructive reads and QZERO

• Each READQ TD removes the record from the queue. Once read, it cannot be read again by any task.
• When the queue is empty, CICS raises the QZERO condition instead of returning data.
• A triggered task should loop READQ TD until QZERO, then end. QZERO also resets trigger processing so the next trigger can fire.
• Use the ASSIGN QNAME command to learn which queue started the task, so one program can serve many queues.

Reading extrapartition queues

• An extrapartition queue must be opened for input before reading.
• Reads return records in the order they were written to the data set.
• End of data set also surfaces as QZERO, so the same loop-until-QZERO pattern works.

Example:-