fatal error: 'Python.h' file not found while installing opencv

Question

I am trying to get opencv 3.1 installed for Python on my Mac OS X 10.10.5 I'm following the steps as outlined here - http://www.pyimagesearch.com/2015/06/15/install-opencv-3-0-and-python-2-7-on-osx/

When I actually try installing opencv after all the setup, I get the following error:

.../opencv/modules/python/src2/cv2.cpp:6:10: fatal error: 
  'Python.h' file not found
 #include <Python.h>
          ^

I looked around StackOverflow and found that most people facing this issue are using Anaconda, which is not my case. It would be great if someone could point me in the right direction to get this fixed.

Thanks,

Did all of it - XCode command line, Brew, python, virtualenv. Also set PATH in bash_profile. Am I missing something? — Sumanth, Mar 03 '16 at 17:22
You need to set C_INCLUDE_PATH try this -> https://stackoverflow.com/a/47956013/4502723 — Aayush Gautam, Dec 23 '17 at 21:10

score 25 · Answer 1 · answered Mar 13 '17 at 23:31

25

If Python.h is not found while making one of the *.cpp files, set the following ENV variable

export CPLUS_INCLUDE_PATH=/System/Library/Frameworks/Python.framework/Headers

Please check the existence of the path in your system and make sure that Python.h is there.

answered Mar 13 '17 at 23:31

Sergey Sargsyan

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`export C_INCLUDE_PATH=/System/Library/Frameworks/Python.framework/Versions/2.7/Headers/` worked for me – Jeff Bezos Nov 10 '22 at 15:55
A couple of useful notes here for when I invariably hit this again: 1. Setting the `PYTHON_DEFAULT_EXECUTABLE` to the version of python of interest is useful 2. Similarly it may be helpful to set, `PYTHONPATH`, `PYTHON_INCLUDE_DIR` to that python's include dirs 3. Use `CPLUS_INCLUDE_PATH` + `C_INCLUDE_PATH` in each case separating multiple dirs with `:` on macos (not sure about other os's) if you need to include other headers such as `numpy`. Finally, don't forget to `-v` the install command to get build output. – toofarsideways Mar 11 '23 at 18:15

score 15 · Answer 2 · answered Mar 03 '16 at 17:18

15

I'm using El Capitan but I don't think there should be much difference in the path to the Python header. I find mine at:

/System/Library/Frameworks/Python.framework/Headers/Python.h

You could try and run:

export C_INCLUDE_PATH=/System/Library/Frameworks/Python.framework/Headers

then try the remaining steps.

answered Mar 03 '16 at 17:18

polarise

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CPLUS_INCLUDE_PATH is used in the accepted answer, though neither worked for me – user1689987 Sep 24 '22 at 00:24
MacOS — `C_INCLUDE_PATH` works, `CPLUS...` — doesn't – Constantine Kurbatov Oct 27 '22 at 00:11
`C_INCLUDE_PATH` was the one that worked for me, `CPLUS_INCLUDE_PATH` didn't. For reference, on an M1 Mac trying to build the wheel for Greenlet. – anden-akkio May 04 '23 at 18:09

score 8 · Answer 3 · edited Oct 22 '22 at 19:19

This question seems to be regarding the default Python2 integrated into the macOS, for which the Python.h header file is in the address:

/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7/Python.h

the Python version might change depending on the macOS version you are using though. However, if you have installed Python3 using Hombrew, as probably you should then you might find the header file in a path like:

/usr/local/Cellar/python/3.7.6_1/Frameworks/Python.framework/Versions/3.7/include/python3.7m/Python.h

depending on the version of Python3 your brew has installed for you. Again there are many other possibilities to get Python on mac (e.g., anaconda, intel python, pypy,... you name it). The best way to find the path to a specific Python.h is to search your entire device with:

sudo find / -iname "Python.h"

Then you can run the command

export C_INCLUDE_PATH="<path/to/the/specific/header/folder>"

in your bash terminal, or add it to the ~/.bash_profile to have it there permanently.

You may wanna also check the MakeFile (or other tooling the software uses e.g., cmake...) to see what versions of Python.h it is expecting and in what locations. it is expecting it.

@ShravyaBoggarapu sorry but this post is from long time ago. I think you should look into CMake `FindPython`. For example [here](https://cmake.org/cmake/help/v3.12/module/FindPython.html). — Foad S. Farimani, Jul 13 '20 at 09:55

Feuda · Answer 4 · 2017-07-19T06:16:39.463

7

Run

brew install python

or

brew upgrade python

after doing this, everything(vim in my case) you want to install will be success.

edited Jul 19 '17 at 06:16

answered Jul 19 '17 at 06:10

Feuda

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This was the clue I needed. I had python 3.8 installed outside brew for some reason. Installing with brew and using that as the base for my virtualenv fixed my woes – Jonas D Nov 04 '22 at 15:26

score 3 · Answer 5 · answered Mar 27 '17 at 13:17

I had the same problem on OSX, fixed by setting the CPLUS_INCLUDE_PATH environment variable. Was also building in an anaconda environment which might have complicated things.

export CPLUS_INCLUDE_PATH=~/anaconda/envs/py27/include/python2.7

cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=~/anaconda/envs/py27/share \
    -D PYTHON2_PACKAGES_PATH=~/anaconda/envs/py27/lib/python2.7/site-packages \
    -D PYTHON2_LIBRARY=~/anaconda/envs/py27/bin/python \
    -D PYTHON_EXECUTABLE=~/anaconda/envs/py27/bin/python \
    -D PYTHON2_INCLUDE_DIR=~/anaconda/envs/py27/include/python2.7 \
    -D INSTALL_C_EXAMPLES=ON -D INSTALL_PYTHON_EXAMPLES=ON \
    -D BUILD_EXAMPLES=ON \
    -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules ..

Thank you, it works also in my case where my virtual env is provided with pyenv — Asmoox, Jan 06 '22 at 20:53

score 3 · Answer 6 · answered Sep 24 '22 at 13:52

3

I solved this problem on mac os 12.2.1 like this: export CPPFLAGS="-I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7" and then pip install ...

answered Sep 24 '22 at 13:52

leach

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I spent a few hours on this error, but this answer solved it for me! – Saransh Oct 21 '22 at 19:17
I would have thought an active `venv` would include or link to the needed python header files but didn't. Those were found in `/usr/local/Cellar/python@3.8/3.8.6/Frameworks/Python.framework/Versions/3.8/include/python3.8` instead. – eliangius Nov 19 '22 at 16:30
1

Thanks, that solved it for me! For those using `pyenv` you can get the location of your headers via `pyenv prefix` + append the remaining path. In my case I had to set `export CPPFLAGS="-I$HOME/.pyenv/versions/3.9.16/include/python3.9"`. – Stan Jan 13 '23 at 13:03

score 1 · Answer 7 · answered Jul 26 '16 at 22:54

First, you have to check and make sure you have installed the python using brew and you are using the system python lib binary. That's was mentioned in the blog.

Second, the python version in the cmake command must match what brew has installed for you. You should double check that.

score 0 · Answer 8 · answered Nov 15 '16 at 17:46

0

Yes, revise the paths used in the cmake command. They must exist in your filesystem. In my case, I have installed python 3.5 and the original documentation uses python 3.4.

answered Nov 15 '16 at 17:46

VICENTE GONZALEZ RUIZ

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score 0 · Answer 9 · answered Jun 13 '17 at 21:47

My approach was different, but it's basically what Jonathan Lau mentioned.

I used pyenv and conda and changed my python lib path which caused the problem. To solve it, here's what I did

Commented out PATH setting for pyenv in .bashrc
Restart terminal and brew install whatever you need (vim in my case)
Change .bashrc back

score 0 · Answer 10 · answered Jun 05 '18 at 19:21

0

I fixed my problem by installing python2.7, apparently it was compiling using python 3.4. So I did the following:

brew install python@2
brew link python@2

answered Jun 05 '18 at 19:21

Younes Nj

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score 0 · Answer 11 · answered May 04 '23 at 14:50

In my case (I tried to install ruamel.yaml.clib via requirements file) the failed command was:

clang -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -iwithsysroot/System/Library/Frameworks/System.framework/PrivateHeaders -iwithsysroot/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.9/Headers -arch arm64 -arch x86_64 -Werror=implicit-function-declaration -Wno-error=unreachable-code -I/Users/<MY_USER>/git/<SOME_PATH>/venv/include -I/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.9/Headers -c _ruamel_yaml.c -o build/temp.macosx-10.9-universal2-cpython-39/_ruamel_yaml.o

And it failed at:

      _ruamel_yaml.c:6:10: fatal error: 'Python.h' file not found

So looking at the command I've figured I need to install Xcode. Not the xcode-select but the Xcode application from the AppStore: https://apps.apple.com/us/app/xcode/id497799835?mt=12

fatal error: 'Python.h' file not found while installing opencv

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