pythondaemonthread

① python daemon thread 什么概念

daemon
A boolean value indicating whether this thread is a daemon thread (True) or not (False). This must be set before start() is called, otherwise RuntimeError is raised. Its initial value is inherited from the creating thread; the main thread is not a daemon thread and therefore all threads created in the main thread default to daemon = False.
The entire Python program exits when no alive non-daemon threads are left.
当daemon被设置为True时，如果主线程退出，那么子线程也将跟着退出，
反之，子线程将继续运行，直到正常退出。