Data Queues

The i5/OS(TM) licensed program uses data queues to send data to the server program. The server program also uses data queues for interprocess communications with other iSeries(TM) applications and API calls.

The data queue must exist before your application uses the virtual terminal APIs to open a path to a virtual terminal. See the Control Language (CL) information for details about creating and deleting data queues. See the Open Virtual Terminal Path (QTVOPNVT) API for information on how a server program specifies the name of the data queue to be used.

The i5/OS licensed program communicates special events to the server program using the data queue. The iSeries provides the information about the special events using a data queue entry.

The following events result in data queue entries being sent:

The following table shows the structure of i5/OS data queue entries that are sent to the data queue when an application uses the virtual terminal APIs. All data queue entries have the same format.

Format for i5/OS Data Queue Entries
Name Type Description
Entry Type CHAR(10) Always set by i5/OS to *VRTTRM.
Entry ID CHAR(2) Entry ID associated with entry. Valid values for the 2 characters in this parameter are:
  1. The i5/OS operating system is closing (terminating) the session with the virtual terminal. The server program should perform a close to indicate that the server program is done using the virtual terminal.
  2. An iSeries application has sent data to the virtual terminal. See Read from Virtual Terminal (QTVRDVT) API for information on how to read the data.

    Note: All other values are reserved by the system.
VTHandle CHAR(16) The virtual terminal handle associated with the virtual terminal communications path previously opened by calling the Open Virtual Terminal Path (QTVOPNVT) API. See Open Virtual Terminal Path (QTVOPNVT) API for additional details.

CHAR(52) Reserved
Key CHAR(*) Key value specified when the virtual terminal communications path was opened. See Open Virtual Terminal Path (QTVOPNVT) API for additional details on specifying the key value. The key value can be used for retrieving data queues by key.


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