gtpi1m3x | System Installation Support Reference |
Standard MQI client support comes with 3 user exits that allow you to
customize the channel interface. These exits are referred to as message
channel agent (MCA) exit routines in the MQSeries publications. These
exits are optional and only called if they have been defined in the MQI
channel directory using the ZMQID DEFINE or ZMQID ALTER command. The
MCA exits are:
- Security
- Normally, security exits work in pairs, one at both the client and server
ends of the channel. This exit is provided to give the customer the
ability to check authorization to start the channel connection. The
security exit is called when the MQI channel is first started.
- Receive
- The receive exit is called after each message segment is received from the
server.
- Send
- The send exit is called just before a message segment is transmitted on
the server.
Programming Considerations
- The interface for the MCA exits are specified in the
cmqxc.h header file. The user exit code will be given
control using the standard ISO-C DLM enter.
- If an irrecoverable error occurs, the MCA user exits can SERRC with
exit. Otherwise, the user exits should always return to the MQI client
support code, only manipulating the data passed in the documented
interface.
- Any fields used in the ECB should be restored to their original values
before returning to the MQI client support code.
- Note:
- For a detailed description on how the MCA exits work, see the MQSeries Distributed Queue Management Guide. For
more information about defining or changing MQI channel definition exit
attributes see the ZMQID DEFINE and ZMQID ALTER command descriptions in TPF Operations.