Summary
There are different ways to extend Python with C + +:
- Swig
- With Boost.Python, you can choose to use Py + + preprocessing
- Use python.
Before the advent of python, Boost.Python was the best way to write C + + extension modules.
Boost.Python is integrated in Boost C++ Libraries. To install on Ubuntu system;
$ sudo apt-get install libboost-python-dev $ sudo apt-get install python-dev
quick get start
hellomodule.cpp
#include <iostream> using namespace std; void say_hello(const char* name) { cout << "Hello " << name << "!\n"; } #include <boost/python/module.hpp> #include <boost/python/def.hpp> using namespace boost::python; BOOST_PYTHON_MODULE(hello) { def("say_hello", say_hello); }
setup.py
#!/usr/bin/env python # Technical support qq group: 144081101 591302926 567351477 nail free group: 21745728 from distutils.core import setup from distutils.extension import Extension setup(name="PackageName", ext_modules=[ Extension("hello", ["hellomodule.cpp"], libraries = ["boost_python"]) ])
Compile:
python2.7 setup.py build running build running build_ext building 'hello' extension creating build/temp.linux-x86_64-2.7 x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -Wdate-time -D_FORTIFY_SOURCE=2 -g -fdebug-prefix-map=/build/python2.7-nbjU53/python2.7-2.7.15~rc1=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -I/usr/include/python2.7 -c hellomodule.cpp -o build/temp.linux-x86_64-2.7/hellomodule.o cc1plus: warning: command line option '-Wstrict-prototypes' is valid for C/ObjC but not for C++ creating build/lib.linux-x86_64-2.7 x86_64-linux-gnu-g++ -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-Bsymbolic-functions -Wl,-z,relro -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -Wdate-time -D_FORTIFY_SOURCE=2 -g -fdebug-prefix-map=/build/python2.7-nbjU53/python2.7-2.7.15~rc1=. -fstack-protector-strong -Wformat -Werror=format-security -Wl,-Bsymbolic-functions -Wl,-z,relro -Wdate-time -D_FORTIFY_SOURCE=2 -g -fdebug-prefix-map=/build/python2.7-nbjU53/python2.7-2.7.15~rc1=. -fstack-protector-strong -Wformat -Werror=format-security build/temp.linux-x86_64-2.7/hellomodule.o -lboost_python -o build/lib.linux-x86_64-2.7/hello.so
Implementation:
$ python2.7 Python 2.7.15rc1 (default, Apr 15 2018, 21:51:34) [GCC 7.3.0] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import hello >>> hello.say_hello("World") Hello World!
What about Python 3?
$ python3 Python 3.6.5 |Anaconda, Inc.| (default, Apr 29 2018, 16:14:56) [GCC 7.2.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import hello Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: /usr/lib/x86_64-linux-gnu/libboost_python-py27.so.1.65.1: undefined symbol: PyClass_Type
setup.py
#!/usr/bin/env python from distutils.core import setup from distutils.extension import Extension setup(name="PackageName", ext_modules=[ Extension("hello", ["hellomodule.cpp"], libraries = ["boost_python"]) ])
Compile:
$ python3 setup.py build running build running build_ext building 'hello' extension creating build creating build/temp.linux-x86_64-3.6 gcc -pthread -B /usr/local/anaconda/compiler_compat -Wl,--sysroot=/ -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/usr/local/anaconda/include/python3.6m -c hellomodule.cpp -o build/temp.linux-x86_64-3.6/hellomodule.o cc1plus: warning: command line option '-Wstrict-prototypes' is valid for C/ObjC but not for C++ creating build/lib.linux-x86_64-3.6 g++ -pthread -shared -B /usr/local/anaconda/compiler_compat -L/usr/local/anaconda/lib -Wl,-rpath=/usr/local/anaconda/lib -Wl,--no-as-needed -Wl,--sysroot=/ build/temp.linux-x86_64-3.6/hellomodule.o -lboost_python3-py36 -o build/lib.linux-x86_64-3.6/hello.cpython-36m-x86_64-linux-gnu.so
Implementation:
$ python3 Python 3.6.5 |Anaconda, Inc.| (default, Apr 29 2018, 16:14:56) [GCC 7.2.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import hello >>> hello.say_hello("World") Hello World!
How to know which python so to use?
$ ll /usr/lib/x86_64-linux-gnu/libboost_python*.so lrwxrwxrwx 1 root root 31 3 Month 618:21 /usr/lib/x86_64-linux-gnu/libboost_python3-py36.so -> libboost_python3-py36.so.1.65.1 lrwxrwxrwx 1 root root 24 3 Month 618:21 /usr/lib/x86_64-linux-gnu/libboost_python3.so -> libboost_python3-py36.so lrwxrwxrwx 1 root root 30 3 Month 618:21 /usr/lib/x86_64-linux-gnu/libboost_python-py27.so -> libboost_python-py27.so.1.65.1 lrwxrwxrwx 1 root root 24 3 Month 618:21 /usr/lib/x86_64-linux-gnu/libboost_python-py36.so -> libboost_python3-py