NAME
	CxMsgData -- obtain a pointer to a commodity message's data area. (V36)

   SYNOPSIS
	data = CxMsgData(cxm);
	D0		 A0

	APTR CxMsgData(struct CxMsg *);

   FUNCTION
	Most commodity messages contain meaningful data such as an InputEvent
	structure. This function returns a pointer to this data.

	You may get a commodity message from a synchronous (custom object) or
	asynchronous (sender object) source. In the second case, 'data' is
	not valid after you have replied to the message.

   INPUTS
	cxm - the commodity message to get the data pointer from (may be NULL)

   RESULTS
	data - a pointer to the message's data, or NULL if 'cxm' is NULL.
	       The meaning of the data varies depending on which kind of
	       object is being inspected.

   BUGS
	Until V38, passing a NULL 'cxm' parameter would cause low-memory
	access and unpredictable results.

	Until V40, whenever the data pointer is a (struct InputEvent), the
	ie_EventAddress field of these structures was not reliable whenever
	the message was generated by a sender object.

   SEE ALSO
	cx_lib/CxSender(), cx_lib/CxCustom()