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| -rw-r--r-- | Doc/library/multiprocessing.rst | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst index 426291c..bc615b8 100644 --- a/Doc/library/multiprocessing.rst +++ b/Doc/library/multiprocessing.rst @@ -254,6 +254,7 @@ processes: p.join() Queues are thread and process safe. + Any object put into a :mod:`~multiprocessing` queue will be serialized. **Pipes** @@ -281,6 +282,8 @@ processes: of corruption from processes using different ends of the pipe at the same time. + The :meth:`~Connection.send` method serializes the the object and + :meth:`~Connection.recv` re-creates the object. Synchronization between processes ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -745,6 +748,11 @@ If you use :class:`JoinableQueue` then you **must** call semaphore used to count the number of unfinished tasks may eventually overflow, raising an exception. +One difference from other Python queue implementations, is that :mod:`multiprocessing` +queues serializes all objects that are put into them using :mod:`pickle`. +The object return by the get method is a re-created object that does not share memory +with the original object. + Note that one can also create a shared queue by using a manager object -- see :ref:`multiprocessing-managers`. @@ -811,6 +819,8 @@ For an example of the usage of queues for interprocess communication see used for receiving messages and ``conn2`` can only be used for sending messages. + The :meth:`~multiprocessing.Connection.send` method serializes the the object using + :mod:`pickle` and the :meth:`~multiprocessing.Connection.recv` re-creates the object. .. class:: Queue([maxsize]) |