FIX: Invalid Enum Value Causes Incompatible Binary Compatible

Last reviewed: December 18, 1997
Article ID: Q171819

The information in this article applies to:

Microsoft Visual Basic Control Creation, Learning, Professional, and Enterprise Editions for Windows, version 5.0

SYMPTOMS

Incompatibility Warnings may appear when you are trying to make a project with binary compatibility even though no subroutine or function declaration has changed.

CAUSE

If a function declaration contains an optional parameter with a default value in the declaration that does not use a valid enum, Visual Basic will define it as a short, which conflicts with the compiled version which is a long.

RESOLUTION

Install Visual Studio 97 Service Pack 2 or use a valid enumeration in the Function or Subroutine declaration.

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:

   ARTICLE-ID: Q170365
   TITLE     : 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:

   ARTICLE-ID: Q171554
   TITLE     : INFO: Visual Basic 5.0 Fixes in Visual Studio 97
               Service Pack 2

MORE INFORMATION

This will only affect optional default parameters that do not use valid enumerations when setting the parameter to a default value.

Steps to Reproduce Behavior

Start a New ActiveX EXE in Visual Basic 5.0.

In the General Declarations section of Class1, place the following code:

      Public sub foo( Optional x as DrawModeConstants = 1)
      End Sub

Select Project1 properties from the Project menu.
Select the Component Tab and then make sure that the Project Compatibility button is selected. Click OK.
Select Make Project1.exe from the File Menu. Click OK.
Select Project1 Properties from the Project menu.
Select the Component Tab and then make sure that Binary Compatibility is selected with the <path>/project1.exe file you recently created showing in the text box. Click OK.
Select Make Project1.exe from the File Menu. Click OK.

You will now get a dialog box that warns of incompatibilities in the declaration of the version-compatible component. This should not be occurring because you have not modified the subroutine declaration. If you continue and select "Accept," you will get another message that recommends canceling the operation.

As a workaround, if the declaration above used a valid enumeration such as the following, the error would not occur:

   Public Sub foo( Optional x as DrawModeConstanst = vbBlackness)
   End Sub

Keywords          : vb5all VS97FixlistSP3 VS97FixlistSP2 VB5FixlistSP2
Version           : 5.0
Platform          : WINDOWS
Issue type        : kbbug
Solution Type     : kbfix kbservicepack

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Last reviewed: December 18, 1997
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