python和c混编_python与C C++混编的四种方式(小结)

混编的含义有两种，

一种是在python里面写C

一种是C里面写python

本文主要是进行简化，方便使用。

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第一种、Python调用C动态链接库(利用ctypes)

pycall.c

/***gcc -o libpycall.so -shared -fPIC pycall.c*/

#include

#include

int foo(int a, int b)

{

printf("you input %d and %d\n", a, b);

return a+b;

}

pycall.py

import ctypes

ll = ctypes.cdll.LoadLibrary

lib = ll("./libpycall.so")

lib.foo(1, 3)

print '***finish***'

运行方法：

gcc -o libpycall.so -shared -fPIC pycall.c

python pycall.py

第2种、Python调用C++(类)动态链接库(利用ctypes)

pycallclass.cpp

#include

using namespace std;

class TestLib

{

public:

void display();

void display(int a);

};

void TestLib::display() {

cout<

}

void TestLib::display(int a) {

cout<

}

extern "C" {

TestLib obj;

void display() {

obj.display();

}

void display_int() {

obj.display(2);

}

}

pycallclass.py

import ctypes

so = ctypes.cdll.LoadLibrary

lib = so("./libpycallclass.so")

print 'display()'

lib.display()

print 'display(100)'

lib.display_int(100)

运行方法：

g++ -o libpycallclass.so -shared -fPIC pycallclass.cpp

python pycallclass.py

第3种、Python调用C和C++可执行程序

main.cpp

#include

using namespace std;

int test()

{

int a = 10, b = 5;

return a+b;

}

int main()

{

cout<

int num = test();

cout<

cout<

}

main.py

import commands

import os

main = "./testmain"

if os.path.exists(main):

rc, out = commands.getstatusoutput(main)

print 'rc = %d, \nout = %s' % (rc, out)

print '*'*10

f = os.popen(main)

data = f.readlines()

f.close()

print data

print '*'*10

os.system(main)

运行方法(只有这种不是生成.so然后让python文件来调用)：

g++ -o testmain main.cpp

python main.py

第4种、扩展Python(C++为Python编写扩展模块)(超级麻烦的一种)

Extest2.c

#include

#include

#include

int fac(int n)

{

if (n < 2) return(1);

return (n)*fac(n-1);

}

char *reverse(char *s)

{

register char t,

*p = s,

*q = (s + (strlen(s) - 1));

while (s && (p < q))

{

t = *p;

*p++ = *q;

*q-- = t;

}

return(s);

}

int test()

{

char s[BUFSIZ];

printf("4! == %d\n", fac(4));

printf("8! == %d\n", fac(8));

printf("12! == %d\n", fac(12));

strcpy(s, "abcdef");

printf("reversing 'abcdef', we get '%s'\n", \

reverse(s));

strcpy(s, "madam");

printf("reversing 'madam', we get '%s'\n", \

reverse(s));

return 0;

}

#include "Python.h"

static PyObject *

Extest_fac(PyObject *self, PyObject *args)

{

int num;

if (!PyArg_ParseTuple(args, "i", &num))

return NULL;

return (PyObject*)Py_BuildValue("i", fac(num));

}

static PyObject *

Extest_doppel(PyObject *self, PyObject *args)

{

char *orig_str;

char *dupe_str;

PyObject* retval;

if (!PyArg_ParseTuple(args, "s", &orig_str))

return NULL;

retval = (PyObject*)Py_BuildValue("ss", orig_str,

dupe_str=reverse(strdup(orig_str)));

free(dupe_str);

return retval;

}

static PyObject *

Extest_test(PyObject *self, PyObject *args)

{

test();

return (PyObject*)Py_BuildValue("");

}

static PyMethodDef

ExtestMethods[] =

{

{ "fac", Extest_fac, METH_VARARGS },

{ "doppel", Extest_doppel, METH_VARARGS },

{ "test", Extest_test, METH_VARARGS },

{ NULL, NULL },

};

void initExtest()

{

Py_InitModule("Extest", ExtestMethods);

}

setup.py

#!/usr/bin/env python

from distutils.core import setup, Extension

MOD = 'Extest'

setup(name=MOD, ext_modules=[Extension(MOD, sources=['Extest2.c'])])

运行方法：

python setup.py build

cd build/lib.Linux-x86_64-2.7

进入python交互模式>>>

import Extest

Extest.test()

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