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import ctypes fails with a statically linked interpreter due to dlopen() failure #81241

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import ctypes fails with a statically linked interpreter due to dlopen() failure#81241
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stdlibStandard Library Python modules in the Lib/ directorytopic-ctypestype-bugAn unexpected behavior, bug, or error

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@indygreg
indygreg
mannequin
opened on May 27, 2019
BPO 37060
Nosy @indygreg

Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-05-27.00:02:41.529>
labels = ['ctypes', '3.7']
title = 'import ctypes fails with a statically linked interpreter due to dlopen() failure'
updated_at = <Date 2019-05-27.00:02:41.529>
user = 'https://github.com/indygreg'

bugs.python.org fields:

activity = <Date 2019-05-27.00:02:41.529>
actor = 'indygreg'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['ctypes']
creation = <Date 2019-05-27.00:02:41.529>
creator = 'indygreg'
dependencies = []
files = []
hgrepos = []
issue_num = 37060
keywords = []
message_count = 1.0
messages = ['343588']
nosy_count = 1.0
nosy_names = ['indygreg']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue37060'
versions = ['Python 3.7']

Linked PRs

Activity

  1. indygreg commented on May 27, 2019

    @indygreg
    indygregmannequin
    on May 27, 2019
    MannequinAuthor

    ctypes/__init__.py calls _ctypes.dlopen(None) on Linux as part of code execution during module import. Unfortunately, dlopen() doesn't work if the current executable isn't a dynamic executable.

    Using a fully statically linked Python executable:

    $ ldd python3.7
        not a dynamic executable
    $ python3.7
>>> import _ctypes

>>> _ctypes.dlopen(None)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: Dynamic loading not supported

>>> import ctypes
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/gps/src/python-build-standalone.git/build/python/install/lib/python3.7/ctypes/__init__.py", line 444, in <module>
    pythonapi = PyDLL(None)
  File "/home/gps/src/python-build-standalone.git/build/python/install/lib/python3.7/ctypes/__init__.py", line 356, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: Dynamic loading not supported

    I think it is a bug that import ctypes raises OSError at import time in this environment. I can make a compelling argument that this error should either be suppressed or converted to an ImportError.

    Producing a fully statically linked Python executable is a bit of work and isn't easily accomplished with the existing build system. My "python-build-standalone" project automates the process. A fully statically linked Python executable is available in the zstd compressed archive at https://github.com/indygreg/python-build-standalone/releases/download/20190505/cpython-3.7.3-linux64-musl-20190526T0219.tar.zst under the python/install/bin/python3.7 path. Simply extract that archive and run that binary to reproduce.

  2. indygreg
    added
    3.7 (EOL)end of life
    topic-ctypes
    on May 27, 2019
  3. ezio-melotti
    transferred this issue fromon Apr 10, 2022

  4. voltagex commented on May 27, 2023

    @voltagex
    voltagex
    on May 27, 2023

    @indygreg did you work out a way around this? I note your https://github.com/indygreg/python-build-standalone/blob/main/cpython-unix/patch-ctypes-static-binary.patch, but this does not seem to fix a static build of Python on its own.

  5. serhiy-storchaka
    added this to Ctypes issueson Jan 1, 2024
  6. zanieb
    removed
    3.7 (EOL)end of life
    on Nov 26, 2025

  7. zanieb commented on Nov 26, 2025

    @zanieb
    zanieb
    on Nov 26, 2025
    Contributor

    I think this issue is still relevant on 3.15+

    cpython/Lib/ctypes/__init__.py

    Line 559 in 7f371ed

    pythonapi = PyDLL(None)

  8. picnixz
    added
    type-bugAn unexpected behavior, bug, or error
    stdlibStandard Library Python modules in the Lib/ directory
    on Jan 24, 2026
  9. ZeroIntensity
    added a commit that references this issue on Sep 28, 2026

    gh-81241: Fix importing `ctypes` from statically linked interpreters (G…

    5637f4e

  10. ZeroIntensity commented on Sep 28, 2026

    @ZeroIntensity
    ZeroIntensity
    on Sep 28, 2026
    Member

    Backports are on auto-merge, and the 3.15 backport will be merged separately.

  11. ZeroIntensity
    closed this as completedon Sep 28, 2026
  12. github-project-automation
    moved this to Done in Ctypes issueson Sep 28, 2026
  13. ZeroIntensity
    added 2 commits that reference this issue on Sep 28, 2026

    [3.13] gh-81241: Fix importing `ctypes` from statically linked interp…

    e3d8d3b

    [3.14] gh-81241: Fix importing `ctypes` from statically linked interp…

    24ddd48
  14. serhiy-storchaka
    added a commit that references this issue on Oct 10, 2026

    [3.15] gh-81241: Fix importing `ctypes` from statically linked interp…

    3440ff9
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