python code to c++ lib or dll - c++

Question

I have some python code that I want to use from C++, I want to build it in lib or dll? how can I do it?
code have dependencies:
import socket
import string
import struct
import sys
and maybe PIL

Answer 1

You can use cython and write thin wrapper to export it to C
Cython lib helloWorld.pyx:
import sys
sys.path.append(".") #yourlib is in current folder
import yourlib #you can import any python module
cdef public void helloWorld():
print "Hello World Cython!"
yourlib.helloWorld("Python")
cdef public int my_sum(int x, int y):
return x*x+y
from libcpp.string cimport string
cdef public string testString( string sx, string sy ):
x = int(sx.c_str())
y = int(sy.c_str())
ret= "%d*%d+%d=%d"%(x,x,y,my_sum(x,y))
cdef char* ret2= ret
return string( ret2 )
Compile with cython (create helloWorld.cpp, helloWorld.h):
cython --cplus helloWorld.pyx
Your code program.cpp:
#include <string>
#include <iostream>
#include "Python.h"
#include "helloWorld.h" // it's cpp header so remove __PYX_EXTERN_C (bug)
int main(int argc, char *argv[]) {
Py_Initialize(); //start python interpreter
inithelloWorld(); //run module helloWorld
helloWorld();
std::cout << testString("6","6") << std::endl; #it's fast!
Py_Finalize();
return 0;
}
Compile and run:
g++ program.cpp helloWorld.cpp -I/usr/include/python2.7/ -lpython2.7
./a.out
Hello World Cython!
Hello World Python!
6*6+6=42
Another way is to use boost::python
Your code program.cpp:
#include <string>
#include <iostream>
#include <boost/python.hpp>
int main(int argc, char *argv[]) {
Py_Initialize();
boost::python::object sys = boost::python::import("sys");
sys.attr("path").attr("append")(".");
boost::python::object main_module = boost::python::import("yourlib");
main_module.attr("helloWorld")("boost_python");
boost::python::object ret= main_module.attr( "my_sum" )( 10, 10 );
std::cout << boost::python::extract<char const*>(ret) << std::endl;
Py_Finalize();
return 0;
}
Compile and run:
g++ program.cpp -I/usr/include/python2.7/ -lpython2.7 -lpython_boost
./a.out
Hello World boost_python!
10*10+10=110

Answer 2

You might want to check how to embed python in another application (http://docs.python.org/extending/embedding.html).