Exception in thread QueueFeederThread (most likely raised during interpreter shutdown)

[Ziliang Chen]

On Thursday, February 21, 2013 2:20:41 AM UTC+8, MRAB wrote:
> On 2013-02-20 08:26, Ziliang Chen wrote: > Hi Guys, > I am using the multiprocessing module. The following code snippet occasionally throws the "Exception in thread QueueFeederThread (most likely raised during interpreter shutdown)" exception. > > I searched google for the cause, someone says there are some issues with the multiprocessing.Queue (need do some sleep at where the queue is used). > > Could you please shed your light here, what is wrong, how can I use the multiprocess correctly ? > > Thanks very much ! > > The python version is 2.6 and on Win7 x64 OS. > > ------------------ > from multiprocessing import Process,Queue > > def listTest(q): > print q.get() > > def queueTest(): > q = Queue() > q.put([1,2,3,4,5,6]) > p = Process(target=listTest,args=(q,)) > p.start() > p.join() > > if __name__=='__main__': > queueTest() > > Exception in thread QueueFeederThread (most likely raised during interpreter shutdown): > I think it may be a race condition. When I tried it, sometimes it failed, sometimes it didn't. It seemed to be better behaved when I put a small sleep at the end to delay the main process exiting.

Thanks, MRAB!
Yeah, I saw such kind of workaround after googling.
But seriously, why is there a race condition here ? Is there any misuse of queue here ?