Function SystemHasAnotherMouseHook

source/hook.cpp:4226–4239

bool SystemHasAnotherMouseHook()
{
	if (sMouseMutex)
		CloseHandle(sMouseMutex); // But don't set it to NULL because we need its value below as a flag.
	HANDLE mutex = CreateMutex(NULL, FALSE, MOUSE_MUTEX_NAME); // Create() vs. Open() has enough access to open the mutex if it exists.
	DWORD last_error = GetLastError();
	// Don't check g_MouseHook because in the case of aChangeIsTemporary, it might be NULL even though
	// we want a handle to the mutex maintained here.
	if (sMouseMutex) // It was open originally, so update the handle the the newly opened one.
		sMouseMutex = mutex;
	else if (mutex) // Keep it closed because the system tracks how many handles there are, deleting the mutex when zero.
		CloseHandle(mutex);  // This facilitates other instances of the program getting the proper last_error value.
	return last_error == ERROR_ALREADY_EXISTS;
}