DOCUMENT:Q171550  18-JUN-2001  [vbwin]
TITLE   :FIX: Recompiling with SP2 Breaks Binary Compatibility
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:WINDOWS:5.0,97,97sps
OPER/SYS:
KEYWORDS:kbVBp500 kbVS97sp2fix kbGrpDSVB kbvbp500sp3fix

======================================================================
-------------------------------------------------------------------------------
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 
-------------------------------------------------------------------------------

SYMPTOMS
========

After adding functionality to a server application (.EXE, .DLL or .OCX) and
recompiling several times with Microsoft Visual Basic version 5.0 with Visual
Studio Service Pack 2 installed, the following errors may occur:

1. Existing client applications may fail when attempting to create an object
   type from the server.

2. The Object Browser may not display all of the classes of the server or all of
   the members of a particular class of the server.

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 3.

For more information, 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 3, please see the following article in the Microsoft Knowledge
Base:

   Q175450 : INFO: Visual Basic 5.0 Fixes in Visual Studio 97 Service Pack 3

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

NOTE: The problems caused by this bug are difficult to reproduce consistently.

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

1. Make an ActiveX DLL (Knowledge Base article Q173407 contains the specific
   steps). After the first compilation (to create the DLL), copy the DLL and
   rename the copy to <filename>.CMP. This will create a file that will
   not be overwritten by future recompiles. (CMP is shorthand for compatible.)
   Then set the server project properties for version compatibility to Binary
   and refer to the .CMP file.

2. Add new functionality to the server without changing any existing
   functionality. Recompile the server to a new DLL. Make a copy of the DLL with
   the extension .CMP.

3. Change the server project version compatibility file to the new .CMP file.
   Add more functionality and recompile to a new DLL. The problems may not
   appear until the third generation of the DLL has been created.

One workaround for the problem is to recompile the server project to a new DLL
and use the new DLL as the binary compatibility file listed in the project
properties dialog.

Additional query words:

======================================================================
Keywords          : kbVBp500 kbVS97sp2fix kbGrpDSVB kbvbp500sp3fix 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVBA500Search kbVB500 kbZNotKeyword3
Version           : WINDOWS:5.0,97,97sps
Issue type        : kbbug
Solution Type     : kbfix

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.