os._exit()用于退出当前进程中的主线程
sys.exit()用于退出当前线程

在另起的进程中使用os._exit()

import os
import threading
import time
from multiprocessing import Process
from threading import Thread


def name():
    thread = threading.current_thread()
    return thread.getName()


def one():
    i = 1
    while True:
        i += 1
        time.sleep(3)
        print("---one---", name())
        if i == 5:
            print("======os._exit======")
            os._exit(0)


def two():
    while True:
        time.sleep(3)
        print("---two---", name())


def process():
    t1 = Thread(target=one, args=())
    t2 = Thread(target=two, args=())
    t1.start()
    t2.start()
    while True:
        time.sleep(3)
        print("---process---", name())


def main():
    p1 = Process(target=process)
    p1.start()
    while True:
        time.sleep(3)
        print("---main---", name())


if __name__ == "__main__":
    main()

执行结果：

当前程序终止在process函数，也就是主函数main()中的p1进程终止，也就是p1进程中的主线程，将会在执行os._exit()后，被终止。但是不会影响主进程中的主线程，比如main()函数会继续执行。

在另起的线程中使用os._exit()

import os
import threading
import time
from threading import Thread


def name():
    thread = threading.current_thread()
    return thread.getName()


def one():
    i = 1
    while True:
        i += 1
        time.sleep(3)
        print("---one---", name())
        if i == 5:
            print("======os._exit======")
            os._exit(0)


def two():
    while True:
        time.sleep(3)
        print("---two---", name())


def process():
    t1 = Thread(target=one, args=())
    t2 = Thread(target=two, args=())
    t1.start()
    t2.start()
    while True:
        time.sleep(3)
        print("---process---", name())


def main():
    p1 = Thread(target=process)
    p1.start()
    while True:
        time.sleep(3)
        print("---main---", name())


if __name__ == "__main__":
    main()

执行结果：

当前程序终止在process函数，也就是主函数main()中的p1线程终止，也就是p1线程中的主线程，将会在执行os._exit()后，被终止，p1线程的主线程是main()中的线程，所以主线程也会结束。

另起进程使用sys.exit()

import sys
import threading
import time
from multiprocessing import Process
from threading import Thread


def name():
    thread = threading.current_thread()
    return thread.getName()


def one():
    i = 1
    while True:
        i += 1
        time.sleep(3)
        print("---one---", name())
        if i == 5:
            print("======sys.exit======")
            sys.exit(0)


def two():
    while True:
        time.sleep(3)
        print("---two---", name())


def process():
    t1 = Thread(target=one, args=())
    t2 = Thread(target=two, args=())
    t1.start()
    t2.start()
    while True:
        time.sleep(3)
        print("---process---", name())


def main():
    p1 = Process(target=process)
    p1.start()
    while True:
        time.sleep(3)
        print("---main---", name())


if __name__ == "__main__":
    main()

执行结果：

执行sys.exit()后，sys.exit()所在的函数线程终止，也就是one()线程终止，但是不会影响其他的子线程和主线程或者其他进程。

另起线程使用sys.exit()

import sys
import threading
import time
from threading import Thread


def name():
    thread = threading.current_thread()
    return thread.getName()


def one():
    i = 1
    while True:
        i += 1
        time.sleep(3)
        print("---one---", name())
        if i == 5:
            print("======sys.exit======")
            sys.exit(0)


def two():
    while True:
        time.sleep(3)
        print("---two---", name())


def process():
    t1 = Thread(target=one, args=())
    t2 = Thread(target=two, args=())
    t1.start()
    t2.start()
    while True:
        time.sleep(3)
        print("---process---", name())


def main():
    p1 = Thread(target=process)
    p1.start()
    while True:
        time.sleep(3)
        print("---main---", name())


if __name__ == "__main__":
    main()

执行结果：

另起线程和另起进程对于sys.exit()来说结果都是一样的，sys.exit()只会对当前的线程进行操作，当前运行是子线程，就会停止子线程，当前运行的是主线程，就会停止主线程。