Using Application.Run in VBA
 

VBA Help gives a syntax:

expression.Run(Macro, Arg1, Arg2, ...)

whe
Macro Required Variant for Syntax 1 (not used with Syntax 2). The macro to
run. This can be either a string with the macro name, a Range object
indicating where the function is, or a register ID for a registered DLL
(XLL) function. If a string is used, the string will be evaluated in the
context of the active sheet.

I have not been able to make this work for functions that I write and put in
a DLL. Most likely, my problem
is I don't know exactly what " a register ID for a registered DLL (XLL)
function" means. How
does one "register" a DLL function in the sense used here?


TIA

Ed