Why does WaitForSingleObject work incorrectly in DLL_PROCESS_DETACH?

Question

C++ / C#

I am writing a DLL.
I call the 1st function, inside it I create a thread:

hThread = CreateThread(NULL, 0, MyThreadFunction, ...);

I want to end the thread, I call the 2nd function:

StopMyThread(hThread); //моя фукнция
WaitForSingleObject(hThread, INFINITE);
CloseHandle(hThread);

Everything works correctly.
Now I want to close the thread if the program that is using the dll calls FreeLibrary. To do this, I process DLL_PROCESS_DETACH in dllmain. I am writing the same code as for the 2nd function, but hangs on WaitForSingleObject(hThread, INFINITE).
Why is this happening?

Answer 1

When DLLMain is called, the system critical section is called, which is also used in functions such as: WaitForSingleObject and others. Replaced WaitForSingleObject with a self-written one - it all worked!

Answer 2

From the DllMain help :

Because DLL notifications are serialized, entry-point functions should not attempt to communicate with other threads or processes. Deadlocks may occur as a result.

Answer 3

You have the same as here