Thread safe (?) way to wait for the main thread

gistfile1.cpp

class Thread : public wxThread {
	int Entry() override {
		for (;;) {
			{
				lock_guard<mutex> lock(m_mutex);
				if (!m_window)
					return 0;

				m_window->CallAfter(&Window::ProvideResult);
			}

			lock_guard<mutex> lock(m_mutexCond);
			while (m_window && !m_window->m_result)
				m_cond.wait(m_mutexCond);

			if (!m_window)
				return 0;

			// ... use m_result ...
		}
	}

	mutex m_mutex, m_mutexCond;
	condition m_cond;
	Window* m_window;
};

class Window : public wxWindow {
	~Window() {
		lock_guard<mutex> lock(m_thread->m_mutex);
		m_thread->m_window = nullptr;
		m_thread->m_cond.notify_one();
	}

	void ProvideResult() {
		m_result = true;
		m_thread->m_cond.notify_one();
	}

	Thread* m_thread;
	bool m_result = false;
};