Chapter 46. Channel-exit calls and data structures

This chapter provides reference information about the special WebSphere MQ calls and data structures used when writing channel exit programs. This is product-sensitive programming interface information. You can write WebSphere MQ user exits in the following programming languages:

You cannot write WebSphere MQ user exits in TAL or Visual Basic. However, a declaration for the MQCD structure is provided in Visual Basic for use on the  MQCONNX  call from an MQ client program.

In a number of cases, parameters are arrays or character strings whose size is not fixed. For these, a lowercase "n" is used to represent a numeric constant. When the declaration for that parameter is coded, the "n" must be replaced by the numeric value required. For further information about the conventions used in these descriptions, see the WebSphere MQ Application Programming Reference book.

The calls are:

• MQ_CHANNEL_EXIT - Channel exit
• MQ_CHANNEL_AUTO_DEF_EXIT - Channel auto-definition exit
• MQ_TRANSPORT_EXIT - Transport retry exit
• MQXWAIT - Wait in exit

The data structures are:

• MQCD - Channel definition
• MQCXP - Channel exit parameter
• MQTXP - Transport exit parameter
• MQXWD - Exit wait descriptor

Note:

Channel exit programs are not supported on DOS or VSE/ESA.