Thread termination on DLL unload

I am trying to write a DLL plugin for third party software. In a plug-in, I create a thread in an init function that is called by the hosting program. However, there is no shutdown procedure where I can terminate the thread correctly. I tried this code:

DLL_EXPORT void InitFunction() // is called by the host application
{
    myThread = std::move(std::thread{myThreadFunction});
}
bool WINAPI DllMain( HINSTANCE hDll, DWORD fdwReason, LPVOID lpvReserved )
{
    switch (fdwReason)
    {
    case DLL_PROCESS_ATTACH:
    {
        DisableThreadLibraryCalls(hDll);
    }   break;
    case DLL_PROCESS_DETACH:
    {
        IsRunning.store(false); // tell the thread it time to terminate;
        if(myThread.joinable())
            myThread.join();
    }break;
    case DLL_THREAD_ATTACH:
        break;
    case DLL_THREAD_DETACH:
        break;
    }
    return true;
}

      

        
        
        
      

    

I know this won't work because windows will call DllMain when the thread ends, but DllMain is still running and hence there will be a dead end. I tried to use DisableThreadLibraryCalls()

in different places in the Dll but that didn't work either. So how can I terminate the threads in my DLL correctly?