Problems with pip install numpy – RuntimeError: Broken toolchain: cannot link a simple C program

If you don’t want to use sudo (so permissions and things like that are preserved when using venv), you can add the ARCHFLAGS declaration to your .bash_profile, and run as normal. This worked for me with Mavericks and Xcode 5.1 using with venv:

In ~/.bash_profile:

export ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future

Then, just run the command:

pip install –upgrade numpy

The problem is that you are unable to compile.

First, make sure that you have accepted the new Terms and Conditions with Xcode. To do this, just open up xCode and accept.

Then, try installing gcc with

brew install gcc

Finally, try to install Numpy with

pip install numpy

Hope this helps.

I simply had to open XCode and accept the agreement and let it install the tools. I then went back to PyCharm and installed numpy again with no issues.

In some cases after OS X upgrades XCode, XCode will require the user (with administrative privileges) to accept a new license. Until the license is accepted, clang and gcc will issue an error when attempting to compile and link code. Or at least python packages.

If you launch XCode and accept the license, the errors no longer appear.

At least, this was the case for me.

This means it can’t find your C compiler.
Try installing the gcc compiler if linking other compiler fails.

For fedora users that are having a similar problem try installing these packeges:

(if not using python3 use python-devel and pip instead of pip3)

sudo dnf install python3-devel
sudo dnf install make automake gcc gcc-c++ gcc-gfortran
sudo dnf install redhat-rpm-config
sudo dnf install subversion

then try

sudo pip3 install numpy

If you are running a linux distribution, you may need a C compiler, especially if you see telltale log lines like sh: gcc: command not found. You can follow the instructions here, which I’ve summarized below:

• Fedora, Red Hat, CentOS, or Scientific Linux

  # yum groupinstall 'Development Tools'

• Debian or Ubuntu Linux

  $ sudo apt-get update
$ sudo apt-get install build-essential manpages-dev

Then you can try rerunning:

sudo pip install numpy

On Fedora 22 this was resolved by updating pip itself:
sudo pip install --upgrade pip

For Docker (Alpine) and Python 3.x this worked for me:

RUN apk update
RUN apk add make automake gcc g++ subversion python3-dev

In my case this happened during a docker build. The problem was that the base image wasn’t fixed to a specific python version and numpy couldn’t compile with the new one.

FROM python:3-slim  # BAD

After I changed it to the following it worked:

FROM python:3.8-slim  # GOOD

Remember to fix your versions! 🙂

I solved this by using Conda instead of pip in my Dockerfile:
FROM continuumio/miniconda3:latest

Old thread, by my problem was that I didn’t have Xcode installed. The following solved it.

xcode-select --install

The Error:

RuntimeError: Broken toolchain: cannot link a simple C program

Means it either can’t find your C compiler or encountered problems linking a simple C program.

Demo docker walkthrough, to get Python2/pip to puke that error:

Keeping this demo confined inside a read-only docker image helps us be fearless in issuing OS-wrecking root level commands and start fresh every time:

#download a read only docker image that doesn't have gcc installed:
docker pull frolvlad/alpine-python2

#check the version of pip and python:
docker run --rm frolvlad/alpine-python2 pip --version
#pip 20.3.4 from /usr/lib/python2.7/site-packages/pip (python 

Try to pip install numpy, you can’t because pip needs gcc:

docker run --rm frolvlad/alpine-python2 pip install --user numpy
#...
#RuntimeError: Broken toolchain: cannot link a simple C program

gcc clearly not installed:

docker run --rm frolvlad/alpine-python2 which gcc
#empty output, gcc is not installed

So install it, now the binary /usr/bin/gcc exists:

docker run --rm frolvlad/alpine-python2 sh -c "apk update && apk add make automake gcc g++ subversion python2-dev && which gcc"
#/usr/bin/gcc

Apologies for stacking terminal commands but this is a read only image so everything has to be redone every time:

Now pip can use gcc and install numpy for python2:

docker run --rm frolvlad/alpine-python2 sh -c "apk update && apk add make automake gcc g++ subversion python2-dev && pip install numpy && python -c 'import numpy as np; print(np.__name__, np.__version__)'"
# ...
#Successfully installed numpy-1.16.6
#('numpy', '1.16.6')

We’re in a good place so freeze the docker image and rename it.

docker images
#choose the most recent container id: 751420a548c1:latest and rename it:
docker commit 751420a548c1:latest frolvlad/alpine-python2_numpy

Now you have a new read only docker image with python2, pip and updated 1.16.6 numpy, ready to run your legacy python2 software like it’s 2005:

docker run --rm frolvlad/alpine-python2_numpy python -c 'import numpy as np; print(np.__name__, np.__version__)'
#('numpy', '1.16.6')

Or to make the above commands simpler and sequential:

Use the -it flag on docker run which means open an interactive terminal from the docker image:

$ docker run -it frolvlad/alpine-python2_numpy sh
/ > python2 -c 'import numpy as np; print(np.__version__)'
1.16.6
/ > which gcc
/usr/bin/gcc
/ > python2 -c 'import numpy as np; print(np.zeros(3))'
[0. 0. 0.]
/ > echo "headward free now to rise"; exit;

As python2 packages fall further into ancient history, pip will have to be configured to point at your a private python2 package repository url.