Lookup the topic/example Application.Caller in the help files

"Koye Li" wrote:

Let say we have defined an UDF fuction foo(a,b) that takes 2 cell references
as its arguments :

public function foo(byval a, byval b)

and on the worksheet, we have

=foo(B1,C1)

Whenever B1 or C1 changes, foo() gets triggered and is called by Excel. Is
there anyway within foo() to tell which argument originated the call?