在执行了几次
有人能解释一下为什么会发生这种情况吗?
os.fork()
之后,我想要与子进程进行数据交换。为此,我使用multiprocessing.Queue
实例。当父进程put数据时,子进程get数据是可行的,但反过来则不行。以下是我的示例代码:import os
import multiprocessing as mp
from queue import Empty
if __name__ == '__main__':
n_workers = 5
forward_queue = mp.Queue()
pids_queue = mp.Queue()
for n in range(n_workers):
forward_queue.put(n)
for n in range(n_workers):
child = os.fork()
if child:
pass
else:
my_number = forward_queue.get()
print('pid={} here, my number is {}'.format(os.getpid(), my_number))
pids_queue.put(os.getpid())
os._exit(0) # correct way to exit a fork according to docs
while True:
try:
pid_of_child = pids_queue.get(timeout=5)
except Empty:
print('no more pids')
break
else:
print('one of my children had this pid={}'.format(pid_of_child))
我得到的输出:
pid=19715 here, my number is 0
pid=19716 here, my number is 1
pid=19717 here, my number is 2
pid=19721 here, my number is 3
pid=19718 here, my number is 4
no more pids
the output I would expect:
pid=19715 here, my number is 0
pid=19716 here, my number is 1
pid=19717 here, my number is 2
pid=19721 here, my number is 3
pid=19718 here, my number is 4
one of my children had this pid=19715
one of my children had this pid=19716
one of my children had this pid=19717
one of my children had this pid=19721
one of my children had this pid=19718
no more pids
有人能解释一下为什么会发生这种情况吗?
os.fork()
相比,你可能最好使用multiprocessing.Process()
。 - petremultiprocessing.Process()
,但这个例子中提取出来的完整情况确实需要执行裸的os.fork()
。 - Lester Jack