A local UAP uses MQPUT to send an MQA message to the queue file in the local system. When MQPUT terminates normally, the message is placed in the local queue file, and the UAP performs its next process. The local queue manager containing the queue file then sends the MQA message to the queue manager in a remote system. The MQA message is placed in the remote queue file for processing by a remote UAP. If you want to communicate interactively, you can define MQPUT to wait for the response from the remote UAP.

Use MQGET to get MQA messages. The timing for receiving MQA messages depends upon whether the message-getting UAP is operating, as described below:

• A local UAP when operating can receive messages from the queue manager by executing MQGET.
• A local UAP that is not operating cannot directly receive messages. The arrival of a message, however, will activate the trigger facility in the queue manager. The Trigger facility then sends notification, called a trigger event, to the trigger monitor application. The trigger monitor application receives the information and decides when to activate the UAP. The user should make sure that the trigger monitor application is active whenever OpenTP1 is active. The user can specify the timing of the activation in the trigger monitor application program.

OpenTP1 can perform MQA message queuing as a transaction. After the UAP updates data, sends the MQA message to the queue manager, and the transaction is committed, the MQA message is placed in the queue file. If the transaction is rolled back, the MQA message in the queue file can be invalidated. For details of transaction, see 3.1 Transaction Control.