cpython-lru_cache-weakref: Doc/lib/libqueue.tex annotate

annotate Doc/lib/libqueue.tex @ 37198:bed3f52f0dc6 legacy-trunk

SF Patch #1455676: Simplify using Queues with daemon consumer threads Adds join() and task_done() methods to track when all enqueued tasks have been gotten and fully processed by daemon consumer threads.

author	Raymond Hettinger <python@rcn.com>
date	Fri, 24 Mar 2006 20:43:29 +0000
parents	73016bd01a71
children	06145fbc7ab9

rev	line source
37198 bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	1
8918 acfffe14628e New section header style. Fred Drake <fdrake@acm.org> parents: 8716 diff changeset	2 \section{\module{Queue} ---
15142 563dee598d3a Fixed lots of small nits caught by Ka-Ping Yee <ping@lfw.org>. Fred Drake <fdrake@acm.org> parents: 12223 diff changeset	3 A synchronized queue class}
563dee598d3a Fixed lots of small nits caught by Ka-Ping Yee <ping@lfw.org>. Fred Drake <fdrake@acm.org> parents: 12223 diff changeset	4
8716 760dcf197048 Adjusted to use the new module synopsis support macros. Fred Drake <fdrake@acm.org> parents: 7877 diff changeset	5 \declaremodule{standard}{Queue}
8918 acfffe14628e New section header style. Fred Drake <fdrake@acm.org> parents: 8716 diff changeset	6 \modulesynopsis{A synchronized queue class.}
8716 760dcf197048 Adjusted to use the new module synopsis support macros. Fred Drake <fdrake@acm.org> parents: 7877 diff changeset	7
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	8
7634 3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	9 The \module{Queue} module implements a multi-producer, multi-consumer
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	10 FIFO queue. It is especially useful in threads programming when
e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	11 information must be exchanged safely between multiple threads. The
7634 3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	12 \class{Queue} class in this module implements all the required locking
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	13 semantics. It depends on the availability of thread support in
e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	14 Python.
e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	15
7634 3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	16 The \module{Queue} module defines the following class and exception:
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	17
e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	18
7634 3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	19 \begin{classdesc}{Queue}{maxsize}
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	20 Constructor for the class. \var{maxsize} is an integer that sets the
e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	21 upperbound limit on the number of items that can be placed in the
e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	22 queue. Insertion will block once this size has been reached, until
e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	23 queue items are consumed. If \var{maxsize} is less than or equal to
e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	24 zero, the queue size is infinite.
7634 3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	25 \end{classdesc}
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	26
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	27 \begin{excdesc}{Empty}
10121 b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	28 Exception raised when non-blocking \method{get()} (or
b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	29 \method{get_nowait()}) is called on a \class{Queue} object which is
32624 73016bd01a71 Bug #788520: Queue class has logic error when non-blocking Tim Peters <tim.peters@gmail.com> parents: 31436 diff changeset	30 empty.
10121 b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	31 \end{excdesc}
b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	32
b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	33 \begin{excdesc}{Full}
b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	34 Exception raised when non-blocking \method{put()} (or
12223 e82e82b3b9ad Merged changes from the 1.5.2p2 release. Fred Drake <fdrake@acm.org> parents: 10121 diff changeset	35 \method{put_nowait()}) is called on a \class{Queue} object which is
32624 73016bd01a71 Bug #788520: Queue class has logic error when non-blocking Tim Peters <tim.peters@gmail.com> parents: 31436 diff changeset	36 full.
7634 3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	37 \end{excdesc}
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	38
7634 3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	39 \subsection{Queue Objects}
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	40 \label{QueueObjects}
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	41
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	42 Class \class{Queue} implements queue objects and has the methods
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	43 described below. This class can be derived from in order to implement
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	44 other queue organizations (e.g. stack) but the inheritable interface
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	45 is not described here. See the source code for details. The public
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	46 methods are:
3d1590b5e3dd Logical markup. Fred Drake <fdrake@acm.org> parents: 7277 diff changeset	47
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	48 \begin{methoddesc}{qsize}{}
10121 b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	49 Return the approximate size of the queue. Because of multithreading
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	50 semantics, this number is not reliable.
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	51 \end{methoddesc}
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	52
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	53 \begin{methoddesc}{empty}{}
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	54 Return \code{True} if the queue is empty, \code{False} otherwise.
32624 73016bd01a71 Bug #788520: Queue class has logic error when non-blocking Tim Peters <tim.peters@gmail.com> parents: 31436 diff changeset	55 Because of multithreading semantics, this is not reliable.
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	56 \end{methoddesc}
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	57
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	58 \begin{methoddesc}{full}{}
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	59 Return \code{True} if the queue is full, \code{False} otherwise.
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	60 Because of multithreading semantics, this is not reliable.
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	61 \end{methoddesc}
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	62
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	63 \begin{methoddesc}{put}{item\optional{, block\optional{, timeout}}}
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	64 Put \var{item} into the queue. If optional args \var{block} is true
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	65 and \var{timeout} is None (the default), block if necessary until a
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	66 free slot is available. If \var{timeout} is a positive number, it
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	67 blocks at most \var{timeout} seconds and raises the \exception{Full}
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	68 exception if no free slot was available within that time.
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	69 Otherwise (\var{block} is false), put an item on the queue if a free
10121 b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	70 slot is immediately available, else raise the \exception{Full}
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	71 exception (\var{timeout} is ignored in that case).
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	72
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	73 \versionadded[the timeout parameter]{2.3}
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	74
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	75 \end{methoddesc}
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	76
10121 b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	77 \begin{methoddesc}{put_nowait}{item}
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	78 Equivalent to \code{put(\var{item}, False)}.
10121 b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	79 \end{methoddesc}
b7d8125c2417 Update documentation to reflect changes to Queue.py by Tim Peters. Guido van Rossum <guido@python.org> parents: 8918 diff changeset	80
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	81 \begin{methoddesc}{get}{\optional{block\optional{, timeout}}}
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	82 Remove and return an item from the queue. If optional args
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	83 \var{block} is true and \var{timeout} is None (the default),
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	84 block if necessary until an item is available. If \var{timeout} is
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	85 a positive number, it blocks at most \var{timeout} seconds and raises
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	86 the \exception{Empty} exception if no item was available within that
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	87 time. Otherwise (\var{block} is false), return an item if one is
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	88 immediately available, else raise the \exception{Empty} exception
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	89 (\var{timeout} is ignored in that case).
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	90
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	91 \versionadded[the timeout parameter]{2.3}
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	92
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	93 \end{methoddesc}
6611 e6b9d21c8e0c libqueue.tex: Documentation for the Queue.py module. Barry Warsaw <barry@python.org> parents: diff changeset	94
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	95 \begin{methoddesc}{get_nowait}{}
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 23997 diff changeset	96 Equivalent to \code{get(False)}.
7768 8f177933c41f Use the new {methoddesc} and {memberdesc} environments as appropriate. Fred Drake <fdrake@acm.org> parents: 7634 diff changeset	97 \end{methoddesc}
37198 bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	98
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	99 Two methods are offered to support tracking whether enqueued tasks have
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	100 been fully processed by daemon consumer threads.
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	101
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	102 \begin{methoddesc}{task_done}{}
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	103 Indicate that a formerly enqueued task is complete. Used by queue consumer
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	104 threads. For each \method{get()} used to fetch a task, a subsequent call to
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	105 \method{task_done()} tells the queue that the processing on the task is complete.
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	106
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	107 If a \method{join()} is currently blocking, it will resume when all items
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	108 have been processed (meaning that a \method{task_done()} call was received
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	109 for every item that had been \method{put()} into the queue).
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	110
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	111 Raises a \exception{ValueError} if called more times than there were items
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	112 placed in the queue.
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	113 \versionadded{2.5}
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	114 \end{methoddesc}
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	115
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	116 \begin{methoddesc}{join}{}
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	117 Blocks until all items in the queue have been gotten and processed.
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	118
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	119 The count of unfinished tasks goes up whenever an item is added to the
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	120 queue. The count goes down whenever a consumer thread calls \method{task_done()}
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	121 to indicate that the item was retrieved and all work on it is complete.
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	122 When the count of unfinished tasks drops to zero, join() unblocks.
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	123 \versionadded{2.5}
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	124 \end{methoddesc}
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	125
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	126 Example of how to wait for enqueued tasks to be completed:
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	127
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	128 \begin{verbatim}
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	129 def worker():
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	130 while True:
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	131 item = q.get()
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	132 do_work(item)
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	133 q.task_done()
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	134
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	135 q = Queue()
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	136 for i in range(num_worker_threads):
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	137 t = Thread(target=worker)
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	138 t.setDaemon(True)
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	139 t.start()
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	140
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	141 for item in source():
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	142 q.put(item)
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	143
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	144 q.join() # block until all tasks are done
bed3f52f0dc6 SF Patch #1455676: Simplify using Queues with daemon consumer threads Raymond Hettinger <python@rcn.com> parents: 32624 diff changeset	145 \end{verbatim}

Mercurial > cpython-lru_cache-weakref

annotate Doc/lib/libqueue.tex @ 37198:bed3f52f0dc6 legacy-trunk