ACC95: DateDiff, DateAdd, or DatePart Causes IPF in VBA232.DLL (169156)

SYMPTOMS

When you pass an uninitialized string variable to the interval argument of the DateAdd(), DatePart(), or DateDiff() functions in Microsoft Access 7.0, you receive the following error message:

MSACCESS caused an invalid page fault in module VBA232.DLL

RESOLUTION

Always pass a valid interval value to the DateAdd(), DatePart(), and DateDiff() functions. To be sure you pass a valid interval value, you can test for the value of the variable before you invoke the function, as in the following example:

   Sub IntervalTest()
      Dim x as String
      If x <> "" Then
         Debug.Print DateAdd(x,1,Date)
      Else
         MsgBox "The interval argument is invalid."
      End If
   End Sub

Another way to prevent the page fault error is to initialize the variable as a zero-length string as soon as you declare it. For example:

   Sub IntervalTest()
      Dim x as String
      x = ""
      ' Add other code here that sets the value of x
      Debug.Print DateAdd(x,1,Date)
   End Sub

Then, if you do not set the value of the variable to a valid interval before you pass it to the DateAdd(), DatePart(), or DateDiff() function, you receive the following error, but Microsoft Access does not terminate:

   Run-time error '5':
   Invalid procedure call

MORE INFORMATION

Steps to Reproduce Problem

WARNING: Following these steps will cause a page fault on your computer. Make sure you save and close any open work on your computer before following these steps.

Start Microsoft Access 7.0 and open the sample database Northwind.mdb.

Create a module and type the following procedure:

      Sub Test()
         Dim x as String
         Debug.Print DateAdd(x,1,Date)
      End Sub

To test this procedure, type the following line in the Debug window, and then press ENTER.

Test

Note that you receive the error message.

NOTE: You may receive an "Out of Stack Space" run-time error, instead of a page fault, the first time you run this procedure. However, subsequent execution of the procedure results in a page fault error.