'_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.