Python进程锁的下面两种用法为什么在Windows系统中执行结果不一样？？？？急！！！

第一段代码
import multiprocessing
import time
lock = multiprocessing.Lock()
def fun():
    lock.acquire()
    for i in range(3):
        time.sleep(0.5)
        print(i)
    lock.release()
    return None
if __name__ == '__main__':
    p1 = multiprocessing.Process(target=fun, args=())
    p2 = multiprocessing.Process(target=fun, args=())
    p1.start()
    p2.start()
执行结果
0
0
1
1
2
2
第二段代码
import multiprocessing
import time
lock = multiprocessing.Lock()
def fun(lock):
    lock.acquire()
    for i in range(3):
        time.sleep(0.5)
        print(i)
    lock.release()
    return None
if __name__ == '__main__':
    p1 = multiprocessing.Process(target=fun, args=(lock,))
    p2 = multiprocessing.Process(target=fun, args=(lock,))
    p1.start()
    p2.start()
第二段代码执行结果
0
1
2
0
1
2