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Q171549: FIX: Cached Class Factorys Get Released by Illegal Thread

Article: Q171549
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:5.0,97
Operating System(s): 
Keyword(s): kbVBp500 kbVS97sp2fix kbGrpDSVBDB kbvbp500sp3fix
Last Modified: 18-JUN-2001

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The information in this article applies to:

- 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
========

Cached Class Factorys can get released by illegal thread.

CAUSE
=====

The repository maintains a cache of class factorys. If a class factory has not
been accessed for a short period of time, the reference to the class factory
will get released. However, the reference is released from a different thread
than the one that initially obtained the reference.

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

The behavior above violates the apartment-threading model, and can cause a
crash.

This behavior is evident when a repository object is implemented in Visual Basic.
This only occurs in Visual Basic where a class is defined as the class that is
the implementation of the generic repository class. This behavior occurs when
the ClassID for the Visual Basic class matches the repository classdef's
ClassID. It crashes when the client creates an instance before the cache is
released. When the engine releases the class factory cache, the crash occurs.

Additional query words:

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

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