'Cmake is not able to find Python-libraries

Getting this error:

sudo: unable to resolve host coderw@ll
-- Could NOT find PythonLibs (missing:  PYTHON_LIBRARIES PYTHON_INCLUDE_DIRS) 
CMake Error at /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:108     
(message):
Could NOT find PythonInterp (missing: PYTHON_EXECUTABLE)
Call Stack (most recent call first):
/usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:315  
(_FPHSA_FAILURE_MESSAGE)
/usr/share/cmake-2.8/Modules/FindPythonInterp.cmake:139 
(FIND_PACKAGE_HANDLE_STANDARD_ARGS)
Code/cmake/Modules/FindNumPy.cmake:10 (find_package)
CMakeLists.txt:114 (find_package)



-- Configuring incomplete, errors occurred!
See also "/home/coderwall/Desktop/rdkit/build/CMakeFiles/CMakeOutput.log".
See also "/home/coderwall/Desktop/rdkit/build/CMakeFiles/CMakeError.log".

I have already installed:

sudo apt-get install python-dev

Environment variable are already set as follow:

PYTHON_INCLUDE_DIRS=/usr/include/python2.7 
PYTHON_LIBRARIES=/usr/lib/python2.7/config/libpython2.7.so

Location of python.h : /usr/lib/include/python2.7/python.h

Location of python libs: /usr/lib/python2.7/ How to solve this?

Solution 1:^[1]

You can fix the errors by appending to the cmake command the -DPYTHON_LIBRARY and -DPYTHON_INCLUDE_DIR flags filled with the respective folders.

Thus, the trick is to fill those parameters with the returned information from the python interpreter, which is the most reliable. This may work independently of your python location/version (also for Anaconda users):

$ cmake .. \
-DPYTHON_INCLUDE_DIR=$(python -c "from distutils.sysconfig import get_python_inc; print(get_python_inc())")  \
-DPYTHON_LIBRARY=$(python -c "import distutils.sysconfig as sysconfig; print(sysconfig.get_config_var('LIBDIR'))")

If the version of python that you want to link against cmake is Python3.X and the default python symlink points to Python2.X, python3 -c ... can be used instead of python -c ....

In case that the error persists, you may need to update the cmake to a higher version as stated by @pdpcosta and repeat the process again.

Solution 2:^[2]

For me this is helpful:

# if using python2
apt-get install python-dev

# if using python3
apt-get install python3-dev

Solution 3:^[3]

I hit the same issue,and discovered the error message gives misleading variable names. Try setting the following (singular instead of plural):

PYTHON_INCLUDE_DIR=/usr/include/python2.7 
PYTHON_LIBRARY=/usr/lib/python2.7/config/libpython2.7.so

The (plural) variables you see error messages about are values that the PythonLibs sets up when it is initialised correctly.

Solution 4:^[4]

Even after adding -DPYTHON_INCLUDE_DIR and -DPYTHON_LIBRARY as suggested above, I was still facing the error Could NOT find PythonInterp. What solved it was adding -DPYTHON_EXECUTABLE:FILEPATH= to cmake as suggested in https://github.com/pybind/pybind11/issues/99#issuecomment-182071479:

cmake .. \
-DPYTHON_INCLUDE_DIR=$(python -c "from distutils.sysconfig import get_python_inc; print(get_python_inc())")  \
-DPYTHON_LIBRARY=$(python -c "import distutils.sysconfig as sysconfig; print(sysconfig.get_config_var('LIBDIR'))") \
-DPYTHON_EXECUTABLE:FILEPATH=`which python`

Solution 5:^[5]

I was facing this problem while trying to compile OpenCV 3 on a Xubuntu 14.04 Thrusty Tahr system. With all the dev packages of Python installed, the configuration process was always returning the message:

Could NOT found PythonInterp: /usr/bin/python2.7 (found suitable version "2.7.6", minimum required is "2.7")
Could NOT find PythonLibs (missing: PYTHON_INCLUDE_DIRS) (found suitable exact version "2.7.6")
Found PythonInterp: /usr/bin/python3.4 (found suitable version "3.4", minimum required is "3.4")
Could NOT find PythonLibs (missing: PYTHON_LIBRARIES) (Required is exact version "3.4.0")

The CMake version available on Thrusty Tahr repositories is 2.8. Some posts inspired me to upgrade CMake. I've added a PPA CMake repository which installs CMake version 3.2.

After the upgrade everything ran smoothly and the compilation was successful.

Solution 6:^[6]

Some last version of Ubuntu installs Python 3.4 by default and the CMake version from Ubuntu (2.8) only searches up to Python 3.3.

Try to add set(Python_ADDITIONAL_VERSIONS 3.4) before the find_package statement.

Remember to clean CMakeCache.txt too.

Solution 7:^[7]

This problem can also happen in Windows. Cmake looks into the registry and sometimes python values are not set. For those with similar problem:

http://ericsilva.org/2012/10/11/restoring-your-python-registry-in-windows/

Just create a .reg file to set the necessary keys and edit accordingly to match your setup.

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Python]

[HKEY_CURRENT_USER\Software\Python\Pythoncore]

[HKEY_CURRENT_USER\Software\Python\Pythoncore\2.6]

[HKEY_CURRENT_USER\Software\Python\Pythoncore\2.6\InstallPath]
@="C:\\python26"

[HKEY_CURRENT_USER\Software\Python\Pythoncore\2.6\PythonPath]
@="C:\\python26;C:\\python26\\Lib\\;C:\\python26\\DLLs\\"

[HKEY_CURRENT_USER\Software\Python\Pythoncore\2.7]

[HKEY_CURRENT_USER\Software\Python\Pythoncore\2.7\InstallPath]
@="C:\\python27"

[HKEY_CURRENT_USER\Software\Python\Pythoncore\2.7\PythonPath]
@="C:\\python27;C:\\python27\\Lib\\;C:\\python27\\DLLs\\"

Solution 8:^[8]

Note that if you are using cMake version 3.12 or later, variable PythonInterp and PythonLibs has been changed into Python.

So we use:

find_package(Python ${PY_VERSION} REQUIRED)

instead of:

find_package(PythonInterp ${PY_VERSION} REQUIRED) find_package(PythonLibs ${PY_VERSION} REQUIRED)

see https://cmake.org/cmake/help/v3.12/module/FindPython.html for details.

Solution 9:^[9]

I had upgraded to python3.8 on my system and had an incomplete install. Managed to fix it by installing the rest of the 3.8 packages:

sudo apt-get install python3.8 python3.8-dev python3.8-distutils python3.8-venv

Solution 10:^[10]

Paste this into your CMakeLists.txt:

# find python
execute_process(COMMAND python-config --prefix OUTPUT_VARIABLE PYTHON_SEARCH_PATH)
string(REGEX REPLACE "\n$" "" PYTHON_SEARCH_PATH "${PYTHON_SEARCH_PATH}")
file(GLOB_RECURSE PYTHON_DY_LIBS ${PYTHON_SEARCH_PATH}/lib/libpython*.dylib ${PYTHON_SEARCH_PATH}/lib/libpython*.so)
if (PYTHON_DY_LIBS)
    list(GET PYTHON_DY_LIBS 0 PYTHON_LIBRARY)
    message("-- Find shared libpython: ${PYTHON_LIBRARY}")
else()
    message(WARNING "Cannot find shared libpython, try find_package")
endif()

find_package(PythonInterp)
find_package(PythonLibs ${PYTHON_VERSION_STRING} EXACT)

Solution 11:^[11]

In case that might help, I found a workaround for a similar problem, looking at the cmake doc : https://cmake.org/cmake/help/v3.0/module/FindPythonLibs.html

You must set two env vars for cmake to find coherent versions. Unfortunately this is not a generic solution...

cmake -DPYTHON_LIBRARY=${HOME}/.pyenv/versions/3.8.0/lib/libpython3.8.a -DPYTHON_INCLUDE_DIR=${HOME}/.pyenv/versions/3.8.0/include/python3.8/ cern_root/

Solution 12:^[12]

Maybe below command line works for you if all of above methods didn't work.

sudo apt-get install cython cython3

Solution 13:^[13]

On Ubuntu 20 at least, since Python 2.7 is deprecated, you can:

sudo apt install python2.7-dev

And then PYTHON_INCLUDE_DIR can be set to /usr/include/python2.7

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	Ivan De Paz Centeno
Solution 2	Yong Kin Chong
Solution 3	Iain Haslam
Solution 4	Lane Rettig
Solution 5	pdpcosta
Solution 6	Patrizio Bertoni
Solution 7	xenon
Solution 8	ZhaoGang
Solution 9	Dylan Kerler
Solution 10	Guo Ang
Solution 11	jojo2000
Solution 12	WangYang
Solution 13	mmerle

'Cmake is not able to find Python-libraries

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