Option Explicit
Private Declare Function GetTickCount Lib "kernel32" () As Long

Dim oApp As Object 'The Excel Application object

Private Sub AddinInstance_OnAddInsUpdate(custom() As Variant)
  Exit Sub
End Sub

Private Sub AddinInstance_OnConnection(ByVal Application As Object, ByVal ConnectMode As AddInDesignerObjects.ext_ConnectMode, ByVal AddInInst As Object, custom() As Variant)
  Set oApp = Application
End Sub

Private Sub AddinInstance_OnDisconnection(ByVal RemoveMode As AddInDesignerObjects.ext_DisconnectMode, custom() As Variant)
  Set oApp = Nothing
End Sub

Private Sub AddinInstance_OnStartupComplete(custom() As Variant)
  Exit Sub
End Sub

Public Function TickCount() As Long
  '----------------------------------------------------------------------
  '** A volatile function that is called each time the sheet is calculated.
  '  Call with =TICKCOUNT().
  '----------------------------------------------------------------------
  oApp.Volatile
  TickCount = GetTickCount
End Function

Public Function Add1(Num1 As Variant, Num2 As Variant) As Variant
  '----------------------------------------------------------------------
  '** A function with two required arguments.
  '  Can be called with formulas such as =Add1(1,3) or =Add1(A1,A2).
  '----------------------------------------------------------------------
  On Error Resume Next
  Add1 = "The sum of " & Num1 & " and " & Num2 & " is " & _
    CDbl(Num1) + CDbl(Num2)
  If Err <> 0 Then Add1 = CVErr(2036) 'xlErrNum = 2036
End Function

Public Function Add2(Num1 As Variant, Num2 As Variant, Optional Num3 As Variant) As Variant
  '----------------------------------------------------------------------
  '** A function with two required arguments and a third optional argument.
  '  Can be called with formulas such as =Add2(1,2), =Add2(A1,A2,A3).
  '----------------------------------------------------------------------
  Dim Sum As Double, sMsg As String
  On Error GoTo Handler
  Sum = CDbl(Num1) + CDbl(Num2)
  If IsMissing(Num3) Then
    sMsg = "The sum of " & Num1 & " and " & Num2 & " is "
  Else
    Sum = Sum + CDbl(Num3)
    sMsg = "The sum of " & Num1 & ", " & Num2 & " and " & Num3 & " is "
  End If
  Add2 = sMsg & Sum
  Exit Function
Handler:
  Add2 = CVErr(2036) 'xlErrNum = 2036
End Function

Public Function Add3(ParamArray Nums()) As Variant
  '----------------------------------------------------------------------
  '** Demonstrates a function with a variable number of arguments.
  '  Can be called with formulas like =Add3(1), =Add3(1,2,3,4),
  '  or =Add3(A1,A2).
  '----------------------------------------------------------------------
  Dim Sum As Double, i As Integer
  On Error GoTo Handler
  For i = 0 To UBound(Nums)
    Sum = Sum + CDbl(Nums(i))
  Next
  Add3 = "The sum is " & Sum
  Exit Function
Handler:
  Add3 = CVErr(2036) 'xlErrNum = 2036
End Function

Public Function ReturnArray(nRows As Long, nCols As Long) As Variant
  '----------------------------------------------------------------------
  '** Demonstrates how to return an array of values (for use in Excel
  '  "array formulas").
  '  Can be called with a formula such as =ReturnArray(1,3).
  '----------------------------------------------------------------------
  On Error GoTo Handler
  ReDim a(0 To nRows, 0 To nCols) As Variant
  Dim r As Long, c As Long
  For r = 0 To nRows - 1
    For c = 0 To nCols - 1
      a(r, c) = "r" & r + 1 & "c" & c + 1
    Next c
  Next r
  ReturnArray = a
  Exit Function
Handler:
  ReturnArray = CVErr(2015) 'xlErrValue = 2015
End Function

Public Function GetArray(Nums As Variant) As Variant
  '----------------------------------------------------------------------
  '** Demonstrates how to use an array(or range of multiple cells) as
  '  a function argument.
  '  Can be called with formulas such as =GetArray(A1:B5), GetArray(A1),
  '  or GetArray({1,2,3;4,5,6}).
  '----------------------------------------------------------------------
  Dim Sum As Double, v As Variant
  On Error GoTo Handler
  If IsArray(Nums) Then
    For Each v In Nums
      Sum = Sum + CDbl(v)
    Next
  Else
    Sum = CDbl(Nums)
  End If
  GetArray = "The sum is " & Sum
  Exit Function
Handler:
  GetArray = CVErr(2036) 'xlErrNum = 2036
End Function