question about multiprocessing

[Gabriel Genellina]

En Sun, 20 Jun 2010 09:43:09 -0300, hywhy <hywhy at live.com> escribió:

> from multiprocessing.managers import BaseManager
> import Queue
>
> class CrawlerManager(BaseManager):
>     pass
>
> downloader_queue = Queue.Queue()
> downloader_queue.put('hello')
>
> CrawlerManager.register('get_downloader_queue', callable=lambda:
> downloader_queue)
>
> mgr = CrawlerManager()
> mgr.start()
>
> q = mgr.get_downloader_queue()
>
>
>
> error:
>
> pickle.PicklingError: Can't pickle <function <lambda> at 0x00C02F70>:  
> it's
> not found as __parents_main__.<lambda>

Multiprocessing uses pickle to transfer data between processes. You can't  
pickle a lambda expression - functions must have a name and be available  
at the outermost module level. (See "Programming guidelines" in the  
multiprocessing documentation, and the pickle module)
But you can't share a Queue object - use the multiprocessing one (see  
"Exchanging data between processes").

-- 
Gabriel Genellina