import time

from threading import Lock,Thread

num = 100

def f1(loc):

    loc.acquire()

    global num

    tmp = num

    tmp -= 1

    time.sleep(0.001)

    num = tmp

    loc.release()

if __name__ == '__main__':

    t_loc = Lock()

    t_list = []

    for i in range(10):

        t = Thread(target=f1,args=(t_loc,))

        t.start()

        t_list.append(t)

    [tt.join() for tt in t_list]

    print("主线程的num:",num)