BUG: Deadlock in multithreaded process if you use Declare statements for APIs in Visual Basic ActiveX .dll files or .ocx files

This article was previously published under Q312218
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If a multithreaded process hosts in-process Visual Basic ActiveX components (.dll or .ocx files), the multithreaded process may experience a deadlock or may stop responding (hang).

Examples of multithreaded processes include:
  • Microsoft COM+ (Dllhost.exe)
  • Microsoft Internet Information Server (Inetinfo.exe)
  • Microsoft Transaction Server (Mtx.exe)
There are many causes for a deadlock in a multithreaded process. One possible cause is the use of Visual Basic 6.0 ActiveX components with Declare statements for application programming interfaces (APIs).
To work around this problem, remove the Declare statements in the ActiveX .dll or .ocx projects, and use a type library to declare those APIs instead.For additional information about how to create and use a type library, click the following article number to view the article in the Microsoft Knowledge Base:
189133 How to make C DLL more accessible to VB with a type library
Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.
in-proc hang DLL OCX IIS MTS multi-threaded

Article ID: 312218 - Last Review: 10/24/2013 08:27:59 - Revision: 4.0

  • Microsoft Visual Basic 6.0 Enterprise Edition
  • kbnosurvey kbarchive kbbug kbnofix KB312218