bpo-31540: Allow passing multiprocessing context to ProcessPoolExecutor (#3682)

1 files changed, 8 insertions, 1 deletions

diff --git a/Doc/library/concurrent.futures.rst b/Doc/library/concurrent.futures.rst
index d85576b8be..30556fbb34 100644
--- a/Doc/library/concurrent.futures.rst
+++ b/Doc/library/concurrent.futures.rst
@@ -191,13 +191,16 @@ that :class:`ProcessPoolExecutor` will not work in the interactive interpreter.
 Calling :class:`Executor` or :class:`Future` methods from a callable submitted
 to a :class:`ProcessPoolExecutor` will result in deadlock.
 
-.. class:: ProcessPoolExecutor(max_workers=None)
+.. class:: ProcessPoolExecutor(max_workers=None, mp_context=None)
 
    An :class:`Executor` subclass that executes calls asynchronously using a pool
    of at most *max_workers* processes.  If *max_workers* is ``None`` or not
    given, it will default to the number of processors on the machine.
    If *max_workers* is lower or equal to ``0``, then a :exc:`ValueError`
    will be raised.
+   *mp_context* can be a multiprocessing context or None. It will be used to
+   launch the workers. If *mp_context* is ``None`` or not given, the default
+   multiprocessing context is used.
 
    .. versionchanged:: 3.3
       When one of the worker processes terminates abruptly, a
@@ -205,6 +208,10 @@ to a :class:`ProcessPoolExecutor` will result in deadlock.
       was undefined but operations on the executor or its futures would often
       freeze or deadlock.
 
+   .. versionchanged:: 3.7
+      The *mp_context* argument was added to allow users to control the
+      start_method for worker processes created by the pool.
+
 
 .. _processpoolexecutor-example: