Embedding Python in C - Cross-platform Development

Embedding Python code into C Linux vs Windows techniques.

Sometimes it's handy to spawn a Python shell from within C programs, or to manipulate Python objects easily from there. Here is a way to embed Python code into C code and have it compile into a native binary (or as a library). The only requirements or course are a working Python 2.x or 3.x installation.

Cross-platform Python Embedding tutorial

Create a test file, embed.c

#include <Python.h>



int main(int argc, char *argv[])

{

    Py_SetProgramName(argv[0]);  /* optional but recommended */

    Py_Initialize();

    PyRun_SimpleString("from time import time,ctime\n"

        "print('Today is', ctime(time()))\n");

    Py_Finalize();

    return 0;

}

Compile & test on Linux x86_64

gcc embed.c $(python-config --cflags --libs) -o embed

./embed

('Today is', 'Tue Jan 27 09:30:30 2015')

Compile & test on Windows64 (or wine). Get our python.exe-config

mingw64-env

$CC embed.c $(wine python C:\\Python27\\python.exe-config --cflags --libs) -o embed.exe

./embed.exe

('Today is', 'Tue Jan 27 09:30:30 2015')

on fail

Cannot find python.exe-config? We made that up to fool Makefiles that embed Python (and make them work with cross-compiling). Name it python.exe-config and put it somewhere in wine's PYTHONPATH. Now such Makefiles should start working.

#!C:\\Python27\python.exe

import sys, subprocess



class ww(object):

    def __init__(self, argv):

        try:

            argv[1]

        except IndexError:

            pass

        else:

            try:

                p=subprocess.check_output(["winepath","c:\\Python27"]).strip()

                q = '/usr/x86_64-w64-mingw32/sys-root/mingw'

            except OSError:

                p = '/c/Python27'

        for x in argv:

            if x == '--includes':

                sys.stdout.write('-I'+p+'/include')

            # change this

            if x == '--prefix' or x == '--exec-prefix':

                sys.stdout.write(' '+p+'/usr')

            if x == '--cflags':

                sys.stdout.write(' -I'+p+'/include -I'+q+'/include -D_WIN32_WINNT=0x0501 -DWINVER=0x0501 -DG_OS_WIN32')

            if x == '--libs':

                sys.stdout.write(' -lpthread -mthreads -lm -lpython27 -L'+p+'/libs -L'+q+'/libs')

            if x == '--ldflags':

                sys.stdout.write(' -lpthread -mthreads -lm -lpython27 -L'+p+'/Python27/libs -L'+q+'/libs -Xlinker -export-dynamic')



if __name__ == "__main__":

    app = ww(sys.argv)

Incompatible libpython27?

ld: skipping incompatible libpython27.a when searching for -lpython27

python27.lib: error adding symbols: File in wrong format

Rebuild Python 2.7's linkable library to a usable format.

cd ~/.wine/drive_c

gendef windows/system32/python27.dll

/usr/bin/x86_64-w64-mingw32-dlltool -D python27.dll -d python27.def -l libpython27.a

References

Link to Python with MinGW

Embed Python into a Windows application