test_threading.py 文件源码

def test_is_alive_after_fork(self):
        # Try hard to trigger #18418: is_alive() could sometimes be True on
        # threads that vanished after a fork.
        old_interval = sys.getcheckinterval()

        # Make the bug more likely to manifest.
        sys.setcheckinterval(10)

        try:
            for i in range(20):
                t = threading.Thread(target=lambda: None)
                t.start()
                pid = os.fork()
                if pid == 0:
                    os._exit(1 if t.is_alive() else 0)
                else:
                    t.join()
                    pid, status = os.waitpid(pid, 0)
                    self.assertEqual(0, status)
        finally:
            sys.setcheckinterval(old_interval)