Break in Visual Studio on process exit

Question

I'm having some difficulties determining what is causing a process to exit. I have a breakpoint in some shutdown code that I'm debugging, but, after breaking in the debugger at the breakpoint and stepping once, the whole process exits immediately. Every thread reports an exit code of -1 in the output window. There are a large number of threads in the process at that time, and the code base is quite large, making searching for the culprit difficult.

I've tried installing a std::atexit function, but this doesn't get hit. I've also tried overriding SetUnhandledExceptionFilter, in case it is caused by a crash, and it also doesn't get hit. The project has exceptions disabled (#define _HAS_EXCEPTIONS=0), so I cannot call std::set_terminate or std::set_unexpected.

Is there some other way to determine what is causing the process to exit? Some option to break in the debugger when the process is about to terminate?

Answer 1

Run your app with debugger and read the debug output. If the app terminates because C++ exceptions, or SEH, you’ll read it in the output window.

If you’ll see nothing interesting there, it means your app called ExitProcess/ExitThread/exit, or worse, TerminateProcess/TerminateThread/_exit.

You can put breakpoints on these. Set a breakpoint at startup, launch debugger. Ensure you have debug symbols loaded for relevant DLLs, kernel32.dll for ExitProcess and friends, some other DLL for exit, e.g. ucrtbase.dll. Press “New / Function breakpoint” in the Breakpoints window, type e.g. “ExitProcess”, press OK.

Answer 2

You can also try using gflags tool from Windows SDK.

If you’ll find (by reading Windows Logs > Application) the reason was self exit, you can check “Enable dump collection” in gflags, then you’ll be able to load the dump in WinDBG and get the complete call stack telling you who called what.

Unfortunately, the latest version of the tool is broken beyond repair.

But you can install older Windows SDK. You only need “Debugging tools for Windows” from there, no need to install the complete SDK.