Can I set a breakpoint in Visual Studio (c++) to break on a thread context switch?

Question

We want to only break in a certain thread. Any idea how to do that? I can't seem to find a way to break on that condition.

I should have been more specific in the text. As the title suggests, I would like to break on the context switch into the thread.

Answer 1

You need to setup a breakpoint filter. Right click on the breakpoint and select the Filter option. It will present a dialog that allows you to filter the breakpoint to specific thread ids, thread names, process ids, process names or even machine names.

If I wanted a breakpoint to only function on thread with id 42 i would use the following filter expression.

ThreadId = 42

Answer 2

I'd be surprised if there were a way to do this in a user-mode debugger.

Imagine: you set a breakpoint for when thread 42 gets switched in. The breakpoint hits. The debugger is activated. Now a different thread is activated, and thread 42 is no longer active!

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I suggest you try Process Monitor from Sysinternals (now part of Microsoft). You can limit it to only capture thread and process events, producing something like the following:

20:43:51.9162409    lsass.exe   440 Thread Create       SUCCESS Thread ID: 5420
20:43:51.9166730    lsass.exe   440 Thread Create       SUCCESS Thread ID: 7916
20:43:53.2990544    svchost.exe 736 Thread Create       SUCCESS Thread ID: 5540
20:43:53.7664146    svchost.exe 736 Thread Create       SUCCESS Thread ID: 7384
20:43:53.7985662    svchost.exe 736 Thread Create       SUCCESS Thread ID: 1888
20:43:54.2444922    wmiprvse.exe    3144    Thread Create       SUCCESS Thread ID: 6300
20:43:54.2466447    svchost.exe 736 Thread Create       SUCCESS Thread ID: 5636
20:43:54.2480367    wmiprvse.exe    3144    Thread Create       SUCCESS Thread ID: 6624
20:43:54.2515443    svchost.exe 736 Thread Create       SUCCESS Thread ID: 7392
20:43:55.5332047    devenv.exe  4640    Thread Exit     SUCCESS Thread ID: 4696, User Time: 0.0000000, Kernel Time: 0.0000000
20:43:55.9179052    Explorer.EXE    3176    Process Create  C:\WINDOWS\system32\verclsid.exe    SUCCESS PID: 3356, Command line: /S /C {2559A1F4-21D7-11D4-BDAF-00C04F60B9F0} /I {000214E6-0000-0000-C000-000000000046} /X 0x401
20:43:55.9179079    verclsid.exe    3356    Process Start       SUCCESS Parent PID: 3176
20:43:55.9179101    verclsid.exe    3356    Thread Create       SUCCESS Thread ID: 7108
20:43:55.9354621    verclsid.exe    3356    Thread Create       SUCCESS Thread ID: 940
20:43:55.9521113    verclsid.exe    3356    Thread Create       SUCCESS Thread ID: 2704
20:43:56.5259637    verclsid.exe    3356    Thread Exit     SUCCESS Thread ID: 2704, User Time: 0.0000000, Kernel Time: 0.0000000

You can do all sorts of other filtering as well, which should allow you to keep the utility running until the problem occurs, even in production.