Channel-exit programs for MQI channels

Three types of channel exit are available to the IBM MQ MQI client environment on UNIX, Linux , and Windows.

These are:

  • Send exit
  • Receive exit
  • Security exit

These exits are available at both the client and the server end of the channel. Exits are not available to our application if you are using the MQSERVER environment variable. Channel exits are explained in Channel exit programs for messaging channels.

The send and receive exits work together. There are several possible ways in which we can use them:

  • Splitting and reassembling a message
  • Compressing and decompressing data in a message (this functionality is provided as part of IBM MQ, but you might want to use a different compression technique)
  • Encrypting and decrypting user data (this functionality is provided as part of IBM MQ, but you might want to use a different encryption technique)
  • Journaling each message sent and received

We can use the security exit to ensure that the IBM MQ client and server are correctly identified, and to control access.

If send or receive exits on the server-connection side of the channel instance need to perform MQI calls on the connection with which they are associated, they use the connection handle provided in the MQCXP Hconn field. You must be aware that client-connection send and receive exits cannot make MQI calls.