CMake can not find PythonLibs

I am trying to build inria Graphite on my ubuntu which is running in a VirtualBox simulator, I follow the instructions, and install the python-dev packages, but when I run cmake , still got an error:

CMake Error at /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:108          (message):
Could NOT find PythonLibs (missing: PYTHON_LIBRARIES PYTHON_INCLUDE_DIRS)
(Required is at least version "3.2")
Call Stack (most recent call first):
 /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:315     (_FPHSA_FAILURE_MESSAGE)
 /usr/share/cmake-2.8/Modules/FindPythonLibs.cmake:208 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
 src/packages/OGF/gel_python3/CMakeLists.txt:11 (FIND_PACKAGE)

I checked the /usr/lib/ and find

tintin@tintin-VirtualBox:/usr/lib$ find . -name "libpython*"
./x86_64-linux-gnu/libpython3.4m.so.1.0
./x86_64-linux-gnu/libpython2.7.so.1.0
./x86_64-linux-gnu/libpython3.4m.a
./x86_64-linux-gnu/libpython2.7.a
./x86_64-linux-gnu/libpython3.4m.so
./x86_64-linux-gnu/libpython2.7.so
./x86_64-linux-gnu/libpython2.7.so.1
./x86_64-linux-gnu/libpython3.4m.so.1

so why cmake can not find the PythonLibs, or how should I deal with this?


Installing python-dev actually fixed this for me:

sudo apt-get install python-dev

Got the hint here: https://github.com/Valloric/YouCompleteMe/issues/484


The problem seems to be that Ubuntu 14.04 installs Python 3.4 by default and the CMake version from Ubuntu (2.8) only searches up to Python 3.3. A workaround is to add set(Python_ADDITIONAL_VERSIONS 3.4) before the find_package statement. Note that I filed a bug about this issue.

Since CMake 3.0, CMake searches up to Python 3.4, so installing that version manually should also fix the problem.


For me the issue was a bad cache

rm CMakeCache.txt

Removed the cache with the old 2.7 version and allowed it to find 3.2 in my case.

The cmake I used is

find_package(PythonInterp 3.2 REQUIRED)
find_package(PythonLibs 3.2 REQUIRED)
message(STATUS "PYTHON_LIBRARIES = ${PYTHON_LIBRARIES}")
message(STATUS "PYTHON_EXECUTABLE = ${PYTHON_EXECUTABLE}")
message(STATUS "PYTHON_INCLUDE_DIRS = ${PYTHON_INCLUDE_DIRS}")
...
include_directories(${PYTHON_INCLUDE_DIRS})

I recently had a similar issue with Ubuntu 14.04 64-bit; apparently, CMake does not look into architecture dependent install folders by default:

CMake constructs a set of possible installation prefixes for the package. Under
each prefix several directories are searched for a configuration file. The tables
below show the directories searched.

[...]

  <prefix>/(lib/<arch>|lib|share)/cmake/<name>*/          (U)
  <prefix>/(lib/<arch>|lib|share)/<name>*/                (U)
  <prefix>/(lib/<arch>|lib|share)/<name>*/(cmake|CMake)/  (U)

[...]

In all cases the <name> is treated as case-insensitive and corresponds to any of
the names specified (<package> or names given by NAMES). Paths with lib/<arch>
are enabled if CMAKE_LIBRARY_ARCHITECTURE is set.

(from CMake 2.8.12 online documentation of the find_package command)

A solution consists in setting this CMAKE_LIBRARY_ARCHITECTURE in the project root CMakeLists.txt file (in your case that would be editing src/packages/OGF/gel_python3/CMakeLists.txt) before calling find_package for PythonLibs; for instance:

cmake_minimum_required(VERSION 2.8)
project(project_name)

# Check the architecture and set CMAKE_LIBRARY_ARCHITECTURE accordingly
if(UNIX)
  if(CMAKE_SIZEOF_VOID_P EQUAL 8)
    set(CMAKE_LIBRARY_ARCHITECTURE "x86_64-linux-gnu")
  endif()
endif()

find_package(PythonInterp 3.2 REQUIRED)
find_package(PythonLibs 3.2 REQUIRED)

# Rest of your file

That worked in my case.