'_posixshmem' has no attribute 'shm_open'

[sunnyguan]

I am encountering some issues when using shared memory:

$ cat test.py
from multiprocessing.shared_memory import SharedMemory
a = SharedMemory("a", create=True, size=1)
a.unlink()

$ /usr/bin/python3 test.py

$ graalpy test.py
Traceback (most recent call last):
  File <...>, line 2, in <module>
    a = SharedMemory("a", create=True, size=1)
  File "/home/ubuntu/.local/graalpy-24.2.1-linux-amd64/lib/python3.11/multiprocessing/shared_memory.py", line 104, in __init__
    self._fd = _posixshmem.shm_open(
AttributeError: module '_posixshmem' has no attribute 'shm_open'

It is indeed missing when looking at dir(_posixshmem), but it exists for CPython.

$ graalpy
>>> import _posixshmem; dir(_posixshmem)
['__doc__', '__loader__', '__name__', '__package__', '__spec__', 'shm_unlink']

Will this be supported in the future?

[msimacek]

Currently, the module is just a skeleton to let things import, but we didn't have time to actually implement it. We don't have any concrete plans for implementing it, since we haven't really encountered anything using it. What is your use case?

[sunnyguan]

I see, I can try to work around it for now then, not a major use case.

[ztawfick-ux]

Currently, the module is just a skeleton to let things import, but we didn't have time to actually implement it. We don't have any concrete plans for implementing it, since we haven't really encountered anything using it. What is your use case?

I am also interested in the functionality that comes with shm_open. I am migrating a codebase from cpython to graalpy, and it uses shared memory for ipc. Ideally, I would like modify the code as little as possible. Is this something that I can easily contribute or will it be more involved?