I am using ubuntu and have installed python 2.7.5 and 3.4.0. For python 2.7.5, I am able to successfully assign a variable x = Value('i', 2) in python 2.7.5, but not 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 python3.4 correctly?
One thing I noticed that python3.4 is installed in usr/local/lib, while python3.3.2 is still installed in usr/lib, so it was not overwritten.
On a fresh Debian image, cloning https://github.com/python/cpython and running:
sudo apt-get update sudo apt-get upgrade sudo apt-get dist-upgrade sudo apt-get install build-essential python-dev python-setuptools python-pip python-smbus sudo apt-get install build-essential libncursesw5-dev libgdbm-dev libc6-dev sudo apt-get install zlib1g-dev libsqlite3-dev tk-dev sudo apt-get install libssl-dev openssl sudo apt-get install libffi-dev
And then
./configure make sudo make altinstall
Got 3.7 installed and working for me.
Thought I'd add the Centos installs:
sudo yum -y install gcc gcc-c++ sudo yum -y install zlib zlib-devel sudo yum -y install libffi-devel
Check python version:
python3 -V
Create virtualenv:
virtualenv -p python3 venv
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
pyenv wiki has the suggestions for various systems to build Python:
https://github.com/pyenv/pyenv/wiki
