[Python-checkins] cpython: Remove outdated statements about threading and imports.
antoine.pitrou
python-checkins at python.org
Fri May 18 13:59:33 CEST 2012
http://hg.python.org/cpython/rev/565734c9b66d
changeset: 77020:565734c9b66d
parent: 77018:364289cc7891
user: Antoine Pitrou <solipsis at pitrou.net>
date: Fri May 18 13:57:04 2012 +0200
summary:
Remove outdated statements about threading and imports.
files:
Doc/library/multiprocessing.rst | 4 +--
Doc/library/threading.rst | 23 ---------------------
2 files changed, 1 insertions(+), 26 deletions(-)
diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -120,9 +120,7 @@
print(q.get()) # prints "[42, None, 'hello']"
p.join()
- Queues are thread and process safe, but note that they must never
- be instantiated as a side effect of importing a module: this can lead
- to a deadlock! (see :ref:`threaded-imports`)
+ Queues are thread and process safe.
**Pipes**
diff --git a/Doc/library/threading.rst b/Doc/library/threading.rst
--- a/Doc/library/threading.rst
+++ b/Doc/library/threading.rst
@@ -996,27 +996,3 @@
Currently, :class:`Lock`, :class:`RLock`, :class:`Condition`,
:class:`Semaphore`, and :class:`BoundedSemaphore` objects may be used as
:keyword:`with` statement context managers.
-
-
-.. _threaded-imports:
-
-Importing in threaded code
---------------------------
-
-While the import machinery is thread-safe, there are two key restrictions on
-threaded imports due to inherent limitations in the way that thread-safety is
-provided:
-
-* Firstly, other than in the main module, an import should not have the
- side effect of spawning a new thread and then waiting for that thread in
- any way. Failing to abide by this restriction can lead to a deadlock if
- the spawned thread directly or indirectly attempts to import a module.
-* Secondly, all import attempts must be completed before the interpreter
- starts shutting itself down. This can be most easily achieved by only
- performing imports from non-daemon threads created through the threading
- module. Daemon threads and threads created directly with the thread
- module will require some other form of synchronization to ensure they do
- not attempt imports after system shutdown has commenced. Failure to
- abide by this restriction will lead to intermittent exceptions and
- crashes during interpreter shutdown (as the late imports attempt to
- access machinery which is no longer in a valid state).
--
Repository URL: http://hg.python.org/cpython
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