DOCUMENT:Q171549 18-JUN-2001 [vbwin] TITLE :FIX: Cached Class Factorys Get Released by Illegal Thread PRODUCT :Microsoft Visual Basic for Windows PROD/VER:WINDOWS:5.0,97 OPER/SYS: KEYWORDS:kbVBp500 kbVS97sp2fix kbGrpDSVBDB kbvbp500sp3fix ====================================================================== ------------------------------------------------------------------------------- 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 ------------------------------------------------------------------------------- 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 ============================================================================= 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.