python进程池multiprocessing.Pool运行错误：The freeze_support() line can be omitted if the program is not g
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import multiprocessing
import time
def func(msg):
print(‘msg: ‘, msg)
time.sleep(1)
print(’----’)
pool = multiprocessing.Pool(processes=4)
for i in range(10):
msg = ‘hello world %d’ % i
pool.apply_async(func, (msg, ))
pool.close()
pool.join()
上面的代码运行将产生如下错误信息：
RuntimeError:
An attempt has been made to start a new process before the
current process has finished its .
This probably means that you are not using fork to start your
child processes and you have forgotten to use the proper idiom
in the main module:
if __name__ == '__main__':
freeze_support()
...
The "freeze_support()" line can be omitted if the program
is not going to be frozen to produce an executable.
**从错误信息可以看出进程池相关代码应该放在if name == 'main ’下面，代码修改如下：
import multiprocessing
import time
def func(msg):
print(‘msg: ‘, msg)
time.sleep(1)
print(’----’)
if name == ‘main ’:
pool = multiprocessing.Pool(processes=4)
for i in range(10):
msg = ‘hello world %d’ % i
pool.apply_async(func, (msg, ))
pool.close()
pool.join()全部评论 (0)
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