BufferLength (MQLONG)
This field is the length in bytes of the message buffer that has been passed to this function.
The buffer can be larger than both the MaxMsgLength value defined for the consumer and the ReturnedLength value in the MQGMO.The actual message length is supplied in DataLength field.
The application can use the entire buffer for its own purposes for the duration of the callback function.
This is an input field to the message consumer function; it is not relevant to an exception handler function.
Parent topic: Fields for MQCBC