BUG: AV Running VB-Built Component in Multi-Threaded Environment
Article ID: 186273
Article Last Modified on 3/3/2005
APPLIES TO
- Microsoft Visual Basic 5.0 Professional Edition
- Microsoft Visual Basic 5.0 Enterprise Edition
- Microsoft Visual Studio 97 Service Pack 3
- Microsoft Visual Studio 97 Service Pack 1
- Microsoft Visual Studio 97 Service Pack 2
- Microsoft Visual Studio 97 Service Pack 3
This article was previously published under Q186273
SYMPTOMS
When running an apartment model ActiveX DLL that is created in Visual Basic in a multithreaded environment such as Microsoft Internet Information
Server (IIS) or Microsoft Transaction Server (MTS), COM+, Internet Explorer, ActiveX EXEs, and so on, the DLL fails
periodically with an access violation (AV).
RESOLUTION
The following steps may be used to change the DLL to avoid the problem.
This may not resolve the issue in all cases.
Step-by-Step Example
- Add a class module to the project.
- Set the name of the class to clsEmpty.
- Set the Instancing property of the class to 2-PublicNotCreatable.
- In Project Properties, set the Start Up Object to Sub Main.
- Add a BAS module, or put the following in an existing BAS module in the project:
Public gEmpty As clsEmpty
Public Sub main()
Set gEmpty = New clsEmpty
End Sub
- Save the project and recompile.
STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.
REFERENCES
For additional information on errors when using an ActiveX DLL created in Visual Basic 5.0 that contains a For... Each loop that iterates through a Visual Basic collection, click the article number below
to view the article in the Microsoft Knowledge Base:
183164 FIX: For..Each Loop in ActiveX Component Causes Errors
For additional information on threading issues with DLLs created in Visual Basic 6.0, click the article number below
to view the article in the Microsoft Knowledge Base:
264957 PRB: Visual Basic DLL Has Memory Leaks and Crashes in COM+ If 'Retain In Memory' Is Not Set
Additional query words: MTS IIS crash gpf ipf
Keywords: kbbug kbtophit kbpending KB186273