Module Module1
Sub Main()
Dim a As Integer, b As Integer, c As Integer
Console.WriteLine("{0} {1} {2}", a, b, c)
subTest(a, b, c)
Console.WriteLine("{0} {1} {2}", a, b, c)
End Sub
Sub subTest(ByRef x As Integer, ByRef y As Integer, ByRef z As Integer)
x = 4
y = 87
z = 999
End Sub
End Module
' run:
'
' 0 0 0
' 4 87 999