Hi!
I wrote the code I pasted at the end of the mail to call a
sub from a dll file. Apparently the code looks correct to
me but instead of returning the correct value of z it
gives me only zeros. Does someone of you see any mistake
for example in the use of the call sub? Thank you
Here is the code:

Declare Sub asum Lib "D:\Dll\arr\koedll.dll" (x As Double,
y As Double, z As Double, n As Integer)
Sub koelarr()
'
' koelarr Macro
' Macro written 10/3/2003 by Claudia Dell'Era Try to link
an array
'

'
Dim x() As Double, y() As Double, z() As Double
Dim n As Integer, i As Integer

Worksheets("Sheet2").Activate
n = Cells(2, 4)

ReDim x(1 To n) As Double, y(1 To n) As Double, z(1 To
n) As Double

Worksheets("Sheet2").Activate
For i = 1 To n
x(i) = Cells(i + 1, 1)
Next i

For i = 1 To n
y(i) = Cells(i + 1, 2)
Next i

Call asum(x(1), y(1), z(1), n)

For i = 1 To n
Cells(i + 1, 3) = z(i)
Next i

End Sub