Hi Folks, Python-dev seemed to be the most appropriate email alias for this, though please do point me somewhere else if this is not appropriate. We are using a custom arm64 based distro built using yocto and as such we are currently using python 3.5.6. We are hitting a failure in a python3 test case qemu running under QEMU that we would like to try to resolve if possible: root@10:/usr/lib/python3.5# python3 --version Python 3.5.6 root@10:/usr/lib/python3.5# python3 ctypes/test/test_structures.py .................F....s..... ====================================================================== FAIL: test_pass_by_value (__main__.StructureTestCase) ---------------------------------------------------------------------- Traceback (most recent call last): File "ctypes/test/test_structures.py", line 419, in test_pass_by_value self.assertEqual(s.first, 0xdeadbeef) AssertionError: 195948557 != 3735928559 ---------------------------------------------------------------------- Ran 28 tests in 0.457s FAILED (failures=1, skipped=1) root@10:/usr/lib/python3.5# From searching the web I came across this bug which appears to match what we are seeing: https://bugs.python.org/issue29804 ("test_ctypes test_pass_by_value fails on arm64 (aarch64) architecture"). However it looks like this fix is already in 3.5.6 so this isn't it. Next set of searching led me here: https://bugs.python.org/issue30353 and thus this patch: https://github.com/python/cpython/commit/9ba3aa4d02a110d1a1ea464a8aff3be7dd9... So I applied this patch but we end up with this now: root@10:~# cd /usr/lib/python3.5/ root@10:/usr/lib/python3.5# python3 ctypes/test/test_structures.py Traceback (most recent call last): File "ctypes/test/test_structures.py", line 2, in <module> from ctypes import * File "/usr/lib/python3.5/ctypes/__init__.py", line 7, in <module> from _ctypes import Union, Structure, Array ImportError: No module named '_ctypes' root@10:/usr/lib/python3.5# Can anyone help point me in the right direction with this failure we are seeing? We are stuck with python 3.5.6 for now due to the version of yocto we are using, though I'm concerned since this seems to be a fairly fundamental issue which is being exposed by this testcase. Do let me know if you require any more information from me. Many Thanks, Peter.