I have 2 versions of python installed, but cmake is using older version. How do I force cmake to use the newer version?
You may try either of these depending on what you need:
CMake >= 3.12
According to the changelog:
New “FindPython3” and “FindPython2” modules, as well as a new
“FindPython” module, have been added to provide a new way to locate
find_package(Python COMPONENTS Interpreter Development)
This module looks preferably for version 3 of Python. If not found,
version 2 is searched. To manage concurrent versions 3 and 2 of
Python, use FindPython3 and FindPython2 modules rather than this one.
CMake < 3.12
find_package(PythonInterp 2.7 REQUIRED) find_package(PythonLibs 2.7 REQUIRED)
Try to add
It might be a path problem?
Also could specify the path to your python library,use your version that you want:
cmake -DPYTHON_LIBRARIES=/Library/Frameworks/Python.framework/Versions/2.7/lib/libpython2.7.dylib .
I had a similar problem, and resolved it using Paul’s answer as a hint. I needed to use
python2.7 to compile an older library, but
cmake keeps picking up my
python3.2 libraries (and executable).
First, I ran
cmake with default options, then edited the
CMakeCache.txt file which it generated. I did it this way primarily because I didn’t know the proper
-D... incantations to cause
cmake to get the python library and include paths, etc right in the first place.
CmakeCache.txt, I found lines like this
Path to a program
Path to a directory
Path to a library
And replaced every occurrence of
python2.7. I also had to rename the
PYTHON_EXECUTABLE to use
python is a symlink to
python3.2 on my system.
Then I reran
cmake. Because it prefers its cached values to actually looking for the libraries, this should work in all cases. At least, it did in mine.
I use anaconda(python 2.7.8) as well as python 2.7.6.
-DPYTHON_EXECUTABLE:FILEPATH=$ANACONDA_HOME/bin, but version 1.4 found (weird:).
My solution is changing it to PYTHON_EXECUTABLE:
cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -DBUILD_TIFF=ON -DPYTHON_LIBRARY=$ANACONDA_HOME/lib/libpython2.7.so -DPYTHON_INCLUDE_DIR=$ANACONDA_HOME/include/python2.7/ -DPYTHON_EXECUTABLE=$ANACONDA_HOME/bin/python
My use case was a rather large project in which C++ classes were made available to Python scripts via
Boost.Python. After having fought the various quirks of CMake’s Python interpreter and library detection, I finally gave up and rolled my own. My approach is based on a slightly after-edited version of the
python-config script that is sometimes (but not always!) put into a newly created virtual environment (see this SO post on
pyvenv for these issues, but I digress). This script is invoked by a small CMake snippet
pyconfig.cmake. Both are freely available from the GitHub repo cmake-python-config.
Warning: The scripts assume that you have a Python 3 interpreter in your
PATH. Detection of Python 2 is not attempted. The scripts do not attempt to find all installed versions of Python3 either.