Connecting to and disconnecting from a queue manager

To use WebSphere® MQ programming services, a program must have a connection to a queue manager. Use this information to learn how to connect to and disconnect from a queue manager.

The way that this connection is made depends on the platform and the environment in which the program is operating:
z/OS® batch, WebSphere MQ for IBM® i, WebSphere MQ on UNIX systems, WebSphere MQ on Linux® systems, and WebSphere MQ for Windows
Programs that run in these environments can use the MQCONN MQI call to connect to, and the MQDISC call to disconnect from, a queue manager. Alternatively, programs can use the MQCONNX call.

z/OS batch programs can connect, consecutively or concurrently, to multiple queue managers on the same TCB.

IMS
The IMS control region is connected to one or more queue managers when it starts. This connection is controlled by IMS commands. However, writers of message queuing IMS programs must use the MQCONN MQI call to specify the queue manager to which they want to connect. They can use the MQDISC call to disconnect from that queue manager.

Following an IMS call that establishes a syncpoint, and before processing a message for another user, the IMS adapter ensures that the application closes handles and disconnects from the queue manager.

IMS programs can connect, consecutively or concurrently, to multiple queue managers on the same TCB.

CICS® Transaction Server for z/OS and CICS for MVS/ESA
CICS programs do not need to do any work to connect to a queue manager because the CICS system itself is connected. This connection is typically made automatically at initialization, but you can also use the CKQC transaction, which is supplied with WebSphere MQ for z/OS.

CICS tasks can connect only to the queue manager to which the CICS region, itself, is connected.

Note: CICS programs can also use the MQI connect and disconnect calls (MQCONN and MQDISC). You might want to do this so that you can port these applications to non-CICS environments with a minimum of recoding. However, these calls always complete successfully in a CICS environment. This means that the return code might not reflect the true state of the connection to the queue manager.
TXSeries® for Windows and Open Systems
These programs do not need to do any work to connect to a queue manager because the CICS system itself is connected. Therefore, only one connection at a time is supported. CICS applications must issue an MQCONN call to obtain a connection handle, and an MQDISC call before they exit.
Use the following links to find out more about connecting and disconnecting from a queue manager: