Multiprocessing queue in py2.7
Frank Miles
fpm at u.washington.edu
Tue Mar 28 16:16:48 EDT 2017
On Tue, 28 Mar 2017 15:38:38 -0400, Terry Reedy wrote:
> On 3/28/2017 2:51 PM, Frank Miles wrote:
>> I tried running a bit of example code from the py2.7 docs
>> (16.6.1.2. Exchanging objects between processes)
>> only to have it fail. The code is simply:
>> # ------------
>> from multiprocessing import Process, Queue
>>
>> def f(q):
>> q.put([42, None, 'hello'])
>>
>> if __name__ == '__main__':
>> q = Queue()
>> p = Process(target=f, args=(q,))
>> p.start()
>> print q.get() # prints "[42, None, 'hello']"
>> p.join()
>> # ---------------
>
> Cut and pasted, this runs as specified on 2.7.13 on Win 10
>
>> But what happens is f() fails:
>>
>> Traceback (most recent call last):
>> File "/usr/lib/python2.7/multiprocessing/process.py", line 258, in _bootstrap
>> self.run()
>> File "/usr/lib/python2.7/multiprocessing/process.py", line 114, in run
>> self._target(*self._args, **self._kwargs)
>> File "x.py", line 4, in f
>> q.put([42, None, "Hello"])
>> AttributeError: 'int' object has no attribute 'put'
>
> This says that the arg bound to q in f is an int rather than a Queue.
> Are you sure that you posted the code that you ran?
>
>> This is on a Debian jessie host, though eventually it needs to
>> run on a raspberry pi 3 {and uses other library code that needs
>> py2.7}.
>>
>> Thanks in advance for those marvelous clues!
Argghh! I missed one stupid typo. Somehow had a '1' instead of the 'q' in the Process(..)
line.
My bad. Sorry for the noise, and thanks!!
-F
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