Single message control

When using the single message control option (by setting field IRM_F5 to IRM_F5_ONE), the client can receive only a single message.

If there are no messages in the IMS OTMA Asynchronous Queue for the client ID when the request is made, no message will be returned and a time out will occur. Using the single message control option will force the following sequence of events to occur:

  1. Client issues CONNECT function.
    1. Following the CONNECT function, if the socket type is persistent socket, one or more transactions can be sent and the responses received before RESUME TPIPE call processing.
    2. If the socket type is a transaction socket, the RESUME TPIPE call must be issued after the CONNECT function.
  2. Client issues RESUME TPIPE call with the correct IRM settings.
  3. Client issues RECEIVE function to receive the Asynchronous output.
  4. Client sends ACK or NAK to IMS Connect.
    1. The ACK or NAK can be sent with a user-specified numeric timeout value.

      Or

    2. Specify NOWAIT for the timeout value.
  5. If a numeric timeout value is specified, the client must issue a RECEIVE function to receive the timeout notification. If the NOWAIT option is specified, no timeout notification is sent. Therefore, the client must not issue a RECEIVE function if NOWAIT is specified.
  6. IMS Connect disconnects the Socket from the Host end if the socket connection is a transaction socket. If the socket connection is a persistent socket, IMS Connect does not disconnect the socket.
  7. Client must issue a DISCONNECT function if the socket connection is a transaction socket. If the socket is a persistent socket, the client can either DISCONNECT the socket or choose to send in a new request such as SENDONLY, SEND of transaction code and data, or issue another RESUME TPIPE call.

If the client responds with a NAK rather than an ACK, the message that has been NAKed will be put back on the OTMA Asynchronous Hold Queue, and can be re-retrieved later. IMS Connect will continue to process as described in events five through seven when a NAK is sent to IMS Connect by the Client.