The Python extension module posix_ipc gives Python access
to POSIX inter-process semaphores, shared memory and message queues on
systems that support the POSIX Realtime Extensions a.k.a. POSIX 1003.1b-1993.
This includes nearly all flavors of Unix, and perhaps Windows + Cygwin or WSL.
It allows Python applications to perform IPC with non-Python programs. If
you want to IPC between Python programs, you're better off using the
multiprocessing module.
As of November 2022, the code and documentation are hosted at GitHub:
https://github.com/osvenskan/posix_ipc/
You can download installable wheels from PyPI.