FIX: Ref to NPV / IRR / MIRR Gives Undefined Functions Error

The information in this article applies to:

- Professional Edition of Microsoft Visual Basic programming system

  for Windows, version 3.0

SYMPTOMS

If you try to run an application that contains a reference to the NPV, IRR, or MIRR financial function, Visual Basic for Windows generates this error:

   Reference to undefined Function or Array

CAUSE

Visual Basic does not recognized these as Visual Basic functions because they were incorrectly referenced in the financial DLL file (MSAFINX.DLL) that ships with Visual Basic version 3.0.

WORKAROUND

To workaround the problem, declare the NPVC, IRRC, and MIRRC functions located in MSAFINX.DLL and alias them as NPV, IRR, and MIRR respectively. The code provided in the More Information section below demonstrates how to declare and call these functions.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This problem has been corrected in Visual Basic version 4.0.

MORE INFORMATION

The following example shows how to use the NPV function. It is based on the example shown in the Visual Basic Help menu, but it also includes the declarations for the NPV, IRR, and MIRR financial functions. Without the declarations for these functions, the example will fail, giving a "Reference to undefined Function or Array" error.

Steps to Work Around the Problem

1. Start Visual Basic or from the File menu, choose New Project (ALT, F, N) if Visual Basic is already running. Form1 is created by default.

2. Add the following code to the General section of Form1:

      ' Enter each Declare statement on one, single line:
      Declare Function MIRRC Lib "MSAFINx.DLL" (values#, ByVal cvalues%,
         ByVal finance#, ByVal reinvest#) As Double
      Declare Function NPVC Lib "MSAFINx.DLL" (ByVal Rate1#, values#,
         ByVal cvalues%) As Double
      Declare Function IRRC Lib "MSAFINx.DLL" (values#, ByVal cvalues%,
         ByVal Guess#) As Double
   
      Function IRR (values() As Double, ByVal Guess As Double) As Double
   
         On Error GoTo IrrErr
         iArgMin% = LBound(values)
         cArg% = UBound(values) - iArgMin%
         IRR = IRRC#(values(iArgMin%), cArg%, Guess)
         Exit Function
   

      MsgBox (Str$(Err))
      Exit Function

   End Function

   ' Enter the following Function statement on one, single line:
   Function MIRR (values() As Double, ByVal finance As Double,
      ByVal reinvest As Double) As Double

      On Error GoTo MirrErr
      iArgMin% = LBound(values)
      cArg% = UBound(values) - iArgMin%
      MIRR = MIRRC#(values(iArgMin%), cArg%, finance, reinvest)
      Exit Function

      MsgBox (Str$(Err))
      Exit Function

   End Function

   Function NPV (ByVal Rate1 As Double, values() As Double) As Double

      On Error GoTo NpvErr
      iArgMin% = LBound(values)
      cArg% = UBound(values) - iArgMin%
      NPV = NPVC#(Rate1, values(iArgMin%), cArg%)
      Exit Function

      MsgBox (Str$(Err))
      Exit Function

   End Function

   Sub Form_Click ()
      Static Values(5) As Double  ' Set up array.
      Fmt = "###,##0.00"  ' Define money format.
      Guess = .1  ' Guess starts at 10%.
      RetRate = .0625 ' Set fixed internal rate.
      Values(0) = -70000  ' Business start-up costs.
      ' Positive cash flows reflecting income for four successive years.
      Values(1) = 22000: Values(2) = 25000
      Values(3) = 28000: Values(4) = 31000
      NetPVal = NPV(RetRate, Values())    ' Calculate net present value.
      Msg = "The net present value of these cash flows is "
      Msg = Msg & Format(NetPVal, Fmt) & "."
      MsgBox Msg  ' Display net present value.
   End Sub