Mailing List Archive: Python: Python

Python3 Multiprocessing

Index | Next | Previous | View Threaded

devyncjohnson at gmail

Aug 9, 2013, 12:30 PM

Post #1 of 5 (23 views)
Permalink

Python3 Multiprocessing

Aloha!

I need a command that will make threads created by
"multiprocessing.Process()" wait for each other to complete. For
instance, I want to do something like this:

job1 = multiprocessing.Process(CMD1())
job2 = multiprocessing.Process(CMD2())

jobs1.start(); jobs2.start()

PY_FUNC()

The command "PY_FUNC()" depends on the end result of the actions of
CMD1() and CMD2(). I need some kind of wait command for the two threads
that will not let the script continue until job1 and job2 are complete.
Is this possible in Python3?

Mahalo,

DevynCJohnson [at] Gmail
--
http://mail.python.org/mailman/listinfo/python-list

python at mrabarnett

Aug 9, 2013, 12:44 PM

Post #2 of 5 (22 views)
Permalink

Re: Python3 Multiprocessing [In reply to]

On 09/08/2013 20:30, Devyn Collier Johnson wrote:
> Aloha!
>
> I need a command that will make threads created by
> "multiprocessing.Process()" wait for each other to complete. For
> instance, I want to do something like this:
>
> job1 = multiprocessing.Process(CMD1())
> job2 = multiprocessing.Process(CMD2())
>
> jobs1.start(); jobs2.start()
>
> PY_FUNC()
>
> The command "PY_FUNC()" depends on the end result of the actions of
> CMD1() and CMD2(). I need some kind of wait command for the two threads
> that will not let the script continue until job1 and job2 are complete.
> Is this possible in Python3?
>
Possibly you mean .join:

jobs1.start()
jobs2.start()

jobs1.join()
jobs2.join()

--
http://mail.python.org/mailman/listinfo/python-list

devyncjohnson at gmail

Aug 9, 2013, 1:43 PM

Post #3 of 5 (22 views)
Permalink

Re: Python3 Multiprocessing [In reply to]

On 08/09/2013 03:44 PM, MRAB wrote:
> On 09/08/2013 20:30, Devyn Collier Johnson wrote:
>> Aloha!
>>
>> I need a command that will make threads created by
>> "multiprocessing.Process()" wait for each other to complete. For
>> instance, I want to do something like this:
>>
>> job1 = multiprocessing.Process(CMD1())
>> job2 = multiprocessing.Process(CMD2())
>>
>> jobs1.start(); jobs2.start()
>>
>> PY_FUNC()
>>
>> The command "PY_FUNC()" depends on the end result of the actions of
>> CMD1() and CMD2(). I need some kind of wait command for the two threads
>> that will not let the script continue until job1 and job2 are complete.
>> Is this possible in Python3?
>>
> Possibly you mean .join:
>
> jobs1.start()
> jobs2.start()
>
> jobs1.join()
> jobs2.join()
>

Thanks MRAB! That is easy. I always (incorrectly) thought the join()
command got two threads and made them one. I did not know it made the
script wait for the threads.

Mahalo,

DevynCJohnson [at] Gmail
--
http://mail.python.org/mailman/listinfo/python-list

ramit.prasad at jpmorgan

Aug 9, 2013, 1:46 PM

Post #4 of 5 (17 views)
Permalink

RE: Python3 Multiprocessing [In reply to]

Devyn Collier Johnson
> On 08/09/2013 03:44 PM, MRAB wrote:
> > On 09/08/2013 20:30, Devyn Collier Johnson wrote:
[snip]
> >>
> > jobs1.join()
> > jobs2.join()
> >
>
> Thanks MRAB! That is easy. I always (incorrectly) thought the join()
> command got two threads and made them one. I did not know it made the
> script wait for the threads.
>

It does join two threads, just not the threads you think! It "joins"
a child thread with the parent thread and not two children thread.

> Mahalo,
>
> DevynCJohnson [at] Gmail
> --

~Ramit

This email is confidential and subject to important disclaimers and conditions including on offers for the purchase or sale of securities, accuracy and completeness of information, viruses, confidentiality, legal privilege, and legal entity disclaimers, available at http://www.jpmorgan.com/pages/disclosures/email.
--
http://mail.python.org/mailman/listinfo/python-list

random832 at fastmail

Aug 9, 2013, 1:54 PM

Post #5 of 5 (22 views)
Permalink

Re: Python3 Multiprocessing [In reply to]

On Fri, Aug 9, 2013, at 16:43, Devyn Collier Johnson wrote:
> Thanks MRAB! That is easy. I always (incorrectly) thought the join()
> command got two threads and made them one. I did not know it made the
> script wait for the threads.

What you're missing is the fact that the main thread [.i.e. the one
running "the script", and that waits for the thread you call the method
on] is, well, a thread. So, you start with two threads [the main thread
and the jobs1 thread, for example], and end up with one [the main
thread]. This is why it's called join.
--
http://mail.python.org/mailman/listinfo/python-list

Index | Next | Previous | View Threaded

Interested in having your list archived? Contact Gossamer Threads