Channel-exit programs for messaging channels
This collection of topics contains information about IBM MQ channel-exit programs for messaging channels.
Message channel agents (MCAs) can also call data-conversion exits. For more information about writing data-conversion exits, see Writing data-conversion exits.
Some of this information also applies to exits on MQI channels, which connect IBM MQ MQI clients to queue managers. For more information, see Channel-exit programs for MQI channels.
Channel-exit programs are called at defined places in the processing carried out by MCA programs.
Some of these user-exit programs work in complementary pairs. For example, if a user-exit program is called by the sending MCA to encrypt the messages for transmission, the complementary process must be functioning at the receiving end to reverse the process.
Table 1 shows the types of channel exit that are available for each channel type.
| Channel Type | Message exit | Message- retry exit | Receive exit | Security exit | Send exit | Auto- definition exit |
|---|---|---|---|---|---|---|
| Sender channel | Yes | Yes | Yes | Yes | ||
| Server channel | Yes | Yes | Yes | Yes | ||
| Cluster- sender channel | Yes | Yes | Yes | Yes | Yes | |
| Receiver channel | Yes | Yes | Yes | Yes | Yes | Yes |
| Requester channel | Yes | Yes | Yes | Yes | Yes | |
| Cluster- receiver channel | Yes | Yes | Yes | Yes | Yes | Yes |
| Client- connection channel | Yes | Yes | Yes | |||
| Server- connection channel | Yes | Yes | Yes | Yes |
- On z/OS®, the auto-definition exit applies to cluster-sender and cluster-receiver channels only.
If you are going to run channel exits on a client, we cannot use the MQSERVER environment variable. Instead, create and reference a client channel definition table (CCDT) as described in Client channel definition table.