Inconsistent behaviour of multiprocessing.shared_memory

Bug report

Bug description:

An example code already exists in the documentation (see from here: The following example demonstrates a practical use of the SharedMemory class with NumPy arrays, accessing the same numpy.ndarray from two distinct Python shells).

The code executes fine as expected and mentioned there until one closes the terminals which report warnings.

When the second terminal is closed: /home/souradeep/miniconda/envs/py39/lib/python3.9/multiprocessing/resource_tracker.py:216: UserWarning: resource_tracker: There appear to be 1 leaked shared_memory objects to clean up at shutdown warnings.warn('resource_tracker: There appear to be %d '

and when the first terminal is closed: /home/souradeep/miniconda/envs/py39/lib/python3.9/multiprocessing/resource_tracker.py:229: UserWarning: resource_tracker: '/trial': [Errno 2] No such file or directory: '/trial'

This can have implications when one tries to use the feature somewhere in an application (see an example).

CPython versions tested on:

3.9

Operating systems tested on:

Linux

Linked PRs

• gh-119126

multiprocessing のドキュメントにある共有メモリの例から始め、multiprocessing/resource_tracker.py を調査します。報告で再現されているシャットダウン時の警告に注目してください。リンクされている PR gh-119126 と、そのテストがあれば確認します。ドキュメント化された例がシャットダウン時に報告された resource-tracker の警告を生成しなくなれば、issue は完了です。