How do you Know if the user want's a return value?

[Sam Finch]

Does anyone know if there's a way for findong out from inside a public function in a usercontrol wheather the user wants a return value or not, ie wheather the user has gone

lngMyVariable=MyFunction(MyParam1,MyParam2)

or just

MyFunction MyParam1,MyParam2.

This would be seriously helpful.