FIX: Problems with Asynchronous Break on Multiprocessor Machines

• Microsoft Visual C++, 32-bit Editions, versions 5.0, 6.0

SYMPTOMS

Debugging a multithreaded application on a multiprocessor machine may show that at some point the asynchronous break fails after a breakpoint is encountered more than once. The CPU usage shows 100 percent busy for all processors in the application that is being debugged. However, this application is not running any useful code and you can not break into it.

In some cases, you may find that the debugger does not break at a breakpoint.

CAUSE

This occurs because of the way that a breakpoint is marked and resumed in a multithreaded application, which affects thread resume operations in a multiprocessor machine.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.This bug was corrected in Visual Studio 6.0 Service Pack 3. For more information about Visual Studio service packs, please see the following articles in the Microsoft Knowledge Base:

Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

Q194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed

Additional query words:

Keywords : kbservicepack kbDebug kbVC500bug kbVC600bug kbVS600sp2 kbVS600SP1 kbVS600sp3fix
Version : winnt:5.0,6.0
Platform : winnt
Issue type : kbbug