守护进程行为多处理多线程

Question

from multiprocessing import Process
from threading import Thread

def main():

    thread1 = myclass(varA)   #subclassed threading.Thread
    thread1.daemon = False
    thread1.start()

    thread2 = Thread(target=myfunc)
    thread2.daemon = False
    thread2.start()

    while True:
        time.sleep(1)


if __name__ == "__main__":

    SUBPROCESS = Process(target=main)
    SUBPROCESS.daemon = False
    SUBPROCESS.start()

除非我在 main() 中添加 while True: sleep，否则为什么脚本会死掉？（thread1 和 thread2 都有永远运行的功能） daemon = False 不应该让它们保持活动状态（子进程和该子进程中的子线程），即使父进程已经结束？

EDIT1（工作代码）（查看方法 A 或方法 B 的注释，注释块运行ning 时的部分之一）：

from multiprocessing import Process
from threading import Thread
import time


varA = "XYZ"

class myclass(Thread):

    def __init__(self, varA):
        Thread.__init__(self)
        self.varA = varA

    def run(self):
        while True:
            print("myClass prints %s" %self.varA)


def myfunc():
    while True:
        print("myfunc prints")



def main():

    thread1 = myclass(varA)   #subclassed threading.Thread
    thread1.daemon = False
    thread1.start()

    thread2 = Thread(target=myfunc)
    thread2.daemon = False
    thread2.start()


if __name__ == "__main__":

    #METHOD A: Running as subprocess = subthreads in that subprocess will die
    SUBPROCESS = Process(target=main)
    SUBPROCESS.daemon = False
    SUBPROCESS.start()


    #METHOD B: Running as main process = subthreads in that subprocess wont die as desired
    thread1 = myclass(varA)   #subclassed threading.Thread
    thread1.daemon = False
    thread1.start()

    thread2 = Thread(target=myfunc)
    thread2.daemon = False
    thread2.start()

Answer 1

这是Python issue 18966；多处理进程在关闭前没有 join 个非守护线程。 Python 3.7.0 中的行为已更改，因此现在处理 join 它们的非守护线程。

守护进程行为多处理多线程

daemon behaviour multiprocessing multithreading

python

python-multiprocessing