import threading
from threading import Thread
from threading import Lock
number=0
lock=Lock()
def work3():
    global number
    for i in range(1000000):
        lock.acquire()#添加锁
        number+=1
        lock.release()#释放锁
    print(number)
def work4():
    global number
    for i in range(1000000):
        lock.acquire(blocking=True)#添加锁
        number+=1
        lock.release()#释放锁
    print(number)
if __name__ == '__main__':
    t3=Thread(target=work3)
    t4=Thread(target=work4)
    t3.start()
    t4.start()
    t3.join()
    t4.join()#如果这里不加join 输出的number 可能不是最终结果
    print(number)