RESUME TPIPE/receive protocol
IMS Connect clients use the RESUME TPIPE protocol to retrieve commit-then-send (CM0) output or synchronous callout requests from a tpipe hold queue in IMS.
Synchronous callout requests are issued by IMS application programs running in an IMS dependent region. Callout requests are for data or services from a provider that is external to the IMS installation. In a callout scenario, the IMS application is the client and the external provider is the server.
Asynchronous output from IMS can include response messages from an IMS transaction and asynchronous callout messages.
For user-written IMS Connect client application programs, the RESUME TPIPE call is coded by specifying the following field values in the IRM prefix:
- IRM_F4
- R character value (IRM_F4_RESUMET).
- IRM_F5
- Hexadecimal value that specifies the retrieval option for the RESUME TPIPE call. The retrieval option specifies how many messages a single RESUME TPIPE call can retrieve and how long the IMS Connect client waits for additional messages when no messages remain on the tpipe hold queue.
- IRM_F6
- A value of X'80' (IRM_F6_NWSE) specifies that the RESUME TPIPE call can retrieve synchronous or asynchronous callout requests that contain the *NETSID* and *NETUID* distributed network security information segments.
- IRM_TIMER
- The timeout value for the RESUME TPIPE call. The value of IRM_TIMER determines how long the client waits for new messages if no output is currently on the tpipe hold queue.
When retrieving synchronous callout messages, in addition to the above fields, you must also specify the following fields to set the IRM architecture level (IRM_ARCH3) and specify whether the IMS Connect client can retrieve synchronous callout message only, or asynchronous output as well:
- IRM_ARCH
- X'03' (IRM_ARCH3). IRM_ARCH3 is required when retrieving synchronous callout messages.
- IRM_F0
- One of the following values must be specified when retrieving
synchronous callout messages:
- X'80' (IRM_F0_SYNONLY). When IRM_F0_SYNONLY is specified, only synchronous callout messages are returned to the IMS Connect client.
- X'40' (IRM_F0_SYNASYN). When IRM_F0_SYNASYN is specified, both synchronous callout messages and asynchronous output are returned to the IMS Connect client.