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author | Antoine Pitrou <solipsis@pitrou.net> | 2012-05-18 11:57:04 (GMT) |
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committer | Antoine Pitrou <solipsis@pitrou.net> | 2012-05-18 11:57:04 (GMT) |
commit | fc6acccbafc82aa91d69b0b86b2a3a36e4f93d23 (patch) | |
tree | 16841d1f67e6484cccf976fb2ea420cfe364aad6 /Doc/library | |
parent | 79341e7865db69ec4f056c7d274aec06bf58a16f (diff) | |
download | cpython-fc6acccbafc82aa91d69b0b86b2a3a36e4f93d23.zip cpython-fc6acccbafc82aa91d69b0b86b2a3a36e4f93d23.tar.gz cpython-fc6acccbafc82aa91d69b0b86b2a3a36e4f93d23.tar.bz2 |
Remove outdated statements about threading and imports.
Diffstat (limited to 'Doc/library')
-rw-r--r-- | Doc/library/multiprocessing.rst | 4 | ||||
-rw-r--r-- | Doc/library/threading.rst | 24 |
2 files changed, 1 insertions, 27 deletions
diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst index 320e492..722f00c 100644 --- a/Doc/library/multiprocessing.rst +++ b/Doc/library/multiprocessing.rst @@ -120,9 +120,7 @@ processes: 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 index 613f304..eaba38b 100644 --- a/Doc/library/threading.rst +++ b/Doc/library/threading.rst @@ -996,27 +996,3 @@ is equivalent to:: 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). |