MQCBCT_* (MQCBC constants Callback type)
| MQCBCT_START_CALL | 1 | X'00000001' |
| MQCBCT_STOP_CALL | 2 | X'00000002' |
| MQCBCT_REGISTER_CALL | 3 | X'00000003' |
| MQCBCT_DEREGISTER_CALL | 4 | X'00000004' |
| MQCBCT_EVENT_CALL | 5 | X'00000005' |
| MQCBCT_MSG_REMOVED | 6 | X'00000006' |
| MQCBCT_MSG_NOT_REMOVED | 7 | X'00000007' |