Python3: ImportError: No module named '_ctypes' when using Value from module multiprocessing

htc_m8 picture htc_m8 · Nov 19, 2014 · Viewed 169.8k times · Source

I am using Ubuntu and have installed Python 2.7.5 and 3.4.0. In Python 2.7.5 I am able to successfully assign a variable x = Value('i', 2), but not in 3.4.0. I am getting:

Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   File "/usr/local/lib/python3.4/multiprocessing/context.py", line 132, in Value
      from .sharedctypes import Value
   File "/usr/local/lib/python3.4/multiprocessing/sharedctypes.py", line 10, in <
module>
   import ctypes
   File "/usr/local/lib/python3.4/ctypes/__init__.py", line 7, in <module>
      from _ctypes import Union, Structure, Array
ImportError: No module named '_ctypes'

I just updated to 3.3.2 through installing the source of 3.4.0. It installed in /usr/local/lib/python3.4.

Did I update to Python 3.4 correctly?

One thing I noticed that Python 3.4 is installed in usr/local/lib, while Python 3.3.2 is still installed in usr/lib, so it was not overwritten.

Answer

dotbit picture dotbit · Dec 31, 2017

Installing libffi-dev and re-installing python3.7 fixed the problem for me.

to cleanly build py 3.7 libffi-dev is required or else later stuff will fail

If using RHEL/Fedora:

yum install libffi-devel

or

sudo dnf install libffi-devel

If using Debian/Ubuntu:

sudo apt-get install libffi-dev