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Q171519: FIX: Removing Function Causes Binary Compatibility Error

Article: Q171519
Product(s): Microsoft Visual Basic for Windows
Version(s): 5.0
Operating System(s): 
Keyword(s): kbVBp500 kbVS97sp2fix kbGrpDSVB kbvbp500sp2fix
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Control Creation Edition for Windows, version 5.0 
- Microsoft Visual Basic Learning Edition for Windows, version 5.0 
- Microsoft Visual Basic Professional Edition for Windows, version 5.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 5.0 
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SYMPTOMS
========

If you recompile an ActiveX DLL with binary compatibility after changing the
interface, Visual Basic will not always warn you. However, this action will
result in an incompatible interface.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual Studio 97 Service
Pack 2.

For more information on the Visual Studio 97 Service Pack 2, please see the
following article in the Microsoft Knowledge Base:

  Q170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why

For a list of the Visual Basic 5.0 bugs that were fixed in the Visual Studio 97
Service Pack 2, please see the following article in the Microsoft Knowledge
Base:

  Q171554 INFO: Visual Basic 5.0 Fixes in Visual Studio 97 Service Pack 2

MORE INFORMATION
================

Changing the interface to an ActiveX DLL (such as changing the arguments in a
function or removing a function) should result in Visual Basic warning you of
the change when you try to compile the new DLL. However, this may not happen.

Steps to Reproduce Behavior
---------------------------

1. Start a new ActiveX DLL in Visual Basic 5.0.

2. Cut and paste the following code to the Class1 Class Module:

         Public Enum Test
           Larry
           Curly
           Moe
         End Enum

         Public Sub Test()
           ' This comment is so this sub compiles
         End Sub

3. Under the Project | Project Properties | Component menu, make sure the
  project's version compatibility is set to "Project Compatibility." (It should
  default to this setting.)

4. Compile Project1.DLL.

5. Comment out the Test Sub.

6. Under the Projects | Properties | Component menu, switch the projects version
  compatibility to "Binary Compatibility." Make sure the compatible version
  file is Project1. (This is the default setting.)

7. Compile Project1 again. This time, save the filename as Project2. Visual
  Basic will compile the DLL without any complaints although it should raise a
  'broken compatibility' warning dialog box.

Additional query words:

======================================================================
Keywords          : kbVBp500 kbVS97sp2fix kbGrpDSVB kbvbp500sp2fix 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVBA500Search kbVBA500 kbVB500 kbZNotKeyword3
Version           : 5.0
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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