BUG: IDE Crash with Compiled GlobalMultiUse (187983)

MORE INFORMATION

Steps to Reproduce Behavior

1. Start a new ActiveX DLL project and name the project P_DLL1.
2. Name its default module C_DLL1Globals and change its Instancing property to GlobalMultiUse.
3. Add the following code to C_DLL1Globals:

         Public Function DLL1_Function() As String
            DLL1_Function = "Func1"
         End Function
   
   						

4. Add a second new ActiveX DLL project and name the project P_DLL2.
5. Name its default module C_DLL2Globals and change it's Instancing property to GlobalMultiUse.
6. Add the following code to C_DLL2Globals:

         Public Sub DLL2_FunctionWhichCallsDLL1_Function()
            Dim s As String
            s = DLL1_Function
   
         End Sub
   
         Public Property Get PublicObject() As C_PublicObject
            Set PublicObject = M_Globals.PublicObject
         End Property
   
   						

7. Add a second Class Module to P_DLL2. Change the name to C_PublicObject and change its Instancing property to PublicNotCreatable.
8. Add the following code to C_PublicObject:

        Private m_Something As Integer
   
        Private Sub Class_Terminate()
           Dim s As String
           s = DLL1_Function
        End Sub
   
        Public Property Let Something(ByVal vData As Integer)
           m_Something = vData
        End Property
   
   						

9. Add a Standard Module to P_DLL2 and name it M_Globals.
10. To create a reference to P_DLL1, click References on the Project menu and check P_DLL1.
11. Add the following code to M_Globals:

         Private m_PublicObject As C_PublicObject
    
         Public Property Get PublicObject() As C_PublicObject
            If m_PublicObject Is Nothing Then
               Set m_PublicObject = New C_PublicObject
            End If
            Set PublicObject = m_PublicObject
         End Property
    
    						

12. Add a Standard EXE project, and name the project GroupExe.
13. Name the default form frmGroupExe, and add a CommandButton to it.
14. Add the following code to frmGroupExe:

          Private Sub Command1_Click()
             DLL2_FunctionWhichCallsDLL1_Function
          End Sub
    
          Private Sub Form_Load()
             PublicObject.Something = 1
          End Sub
    
    						

15. Save the project files.
16. Compile P_DLL1.dll and remove the P_DLL1 project from the project group by choosing Remove Project from the File menu.
17. Compile P_DLL2.dll and remove the P_DLL2 project from the project group by choosing Remove Project from the File menu.
18. In GroupExe, create a reference to P_DLL2.
19. Save your work.
    
    NOTE: The next step will crash the IDE and you may lose your work if you do not save it at this time.
20. Run GroupExe, click the CommandButton, and then exit GroupExe. Note that the IDE crashes with one of the errors mentioned previously.

This problem occurs during the shut down process. If you were to trace the order in which the classes in the two DLLs shut down, you would see the following order of events:

C_DLL2Globals Terminate
C_DLL1Globals Terminate
C_PublicObject Terminate

The problem occurs when the Terminate event of C_PublicObject tries to call the DLL1_Function, which is in the C_DLL1Globals object. Because the C_DLL1Globals object has closed, the DLL1_Function cannot be called.

To work around this problem, make sure the C_PublicObject Terminate event occurs while the C_DLL1Globals object is still available. To accomplish this task, put code in the Terminate event of C_DLL2Globals that causes the C_PublicObject to terminate. This will force the C_PublicObject Terminate event to fire before the C_DLL1Globals object is closed. Here's the code modifications for the workaround:

Put the following procedure in the M_Globals module of P_DLL2:

   Public Sub ClosePublicObject
      Set m_PublicObject = Nothing
   End Sub
				

Next, add the following code to the C_DLL2Globals class:

   Private Sub Class_Terminate()
      ClosePublicObject
   End Sub
				

Now, when C_DLL2Globals terminates, the ClosePublicObject procedure is run that causes the C_PublicObject object to terminate. The new order of events during shutdown is:

C_DLL2Globals Terminate
C_PublicObject Terminate
C_DLL1Globals Terminate