Issue 27747: Broken example in the queue module documentation (original) (raw)

Issue27747

Created on 2016-08-12 14:01 by Paulo Gabriel Poiati, last changed 2022-04-11 14:58 by admin. This issue is now closed.

Messages (3)
msg272540 - (view)	Author: Paulo Gabriel Poiati (Paulo Gabriel Poiati)	Date: 2016-08-12 14:01
I believe the code example at https://docs.python.org/3.6/library/queue.html is broken. The break condition in the worker loop (when the queued value is None) must call the `task_done` before breaking, otherwise the code blocks indefinitely in the `queue.join()` statement.
msg272542 - (view)	Author: R. David Murray (r.david.murray) *	Date: 2016-08-12 14:42
The example looks correct to me. Have you tested it and seen it hang? The q.join() is done, and returns once all the puts have been processed. *Then* None is put for each worker, which terminates the worker thread. There's no q.join() to block at that point.
msg272547 - (view)	Author: Paulo Gabriel Poiati (Paulo Gabriel Poiati)	Date: 2016-08-12 17:24
You are absolutely right David. I was calling join after putting `None` in the queue. Sorry, I'm closing this.