Ubuntu下Python与C/C++混合编程

转载自：
博主：飞越彩虹；
来源：博客园；

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C++调用Python

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Python模块代码:

#!/usr/bin/python
#Filename:TestModule.py
def Hello(s):
    print "Hello World"
    print s

def Add(a, b):
    print 'a=', a
    print 'b=', b
    return a + b

class Test:
    def __init__(self):
        print "Init"
    def SayHello(self, name):
        print "Hello,", name
        return name

C++代码:

#include<iostream>
#include<Python.h>
using namespace std;
int main(int argc, char* argv[])
{
   //初始化python
   Py_Initialize();

   //直接运行python代码
   PyRun_SimpleString("print 'Python Start'");

   //引入当前路径,否则下面模块不能正常导入
   PyRun_SimpleString("import sys");  
   PyRun_SimpleString("sys.path.append('./')");  

   //引入模块
   PyObject *pModule = PyImport_ImportModule("TestModule");
   //获取模块字典属性
   PyObject *pDict = PyModule_GetDict(pModule);

   //直接获取模块中的函数
   PyObject *pFunc = PyObject_GetAttrString(pModule, "Hello");

   //参数类型转换，传递一个字符串。将c/c++类型的字符串转换为python类型，元组中的python类型查看python文档
   PyObject *pArg = Py_BuildValue("(s)", "Hello Charity");

   //调用直接获得的函数，并传递参数
   PyEval_CallObject(pFunc, pArg);

   //从字典属性中获取函数
   pFunc = PyDict_GetItemString(pDict, "Add");
   //参数类型转换，传递两个整型参数
   pArg = Py_BuildValue("(i, i)", 1, 2);

   //调用函数，并得到python类型的返回值
   PyObject *result = PyEval_CallObject(pFunc, pArg);
   //c用来保存c/c++类型的返回值
   int c;
   //将python类型的返回值转换为c/c++类型
   PyArg_Parse(result, "i", &c);
   //输出返回值
   printf("a+b=%d\n", c);

   //通过字典属性获取模块中的类
   PyObject *pClass = PyDict_GetItemString(pDict, "Test");

   //实例化获取的类
   PyObject *pInstance = PyInstance_New(pClass, NULL, NULL);
   //调用类的方法
   result = PyObject_CallMethod(pInstance, "SayHello", "(s)", "Charity");
   //输出返回值
   char* name=NULL;
   PyArg_Parse(result, "s", &name);
   printf("%s\n", name);

   PyRun_SimpleString("print 'Python End'");

   //释放python
   Py_Finalize();
   getchar();
   return 0;
}

编译:

g++ -I/usr/include/python2.7 PythonWithCpp.cpp -lpython2.7

运行结果:

Python Start
Hello World
Hello Charity
a= 1
b= 2
a+b=3
Init
Hello, Charity
Charity
Python End

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Python调用C++

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C++代码:

//用C++必须在函数前加extern "C"
 extern "C" int Add(int a,int b)
{
     return a+b;
}

编译:

g++ -c -fPIC LibPythonTest.cpp
g++ -shared LibPythonTest.o -o LibPythonTest.so

Python代码:

#!/bin/python
#Filename:PythonCallCpp.py
from ctypes import *
import os
libPythonTest = cdll.LoadLibrary('./LibPythonTest.so')
print libPythonTest.Add(1,1)

运行:

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python PythonCallCpp.py

运行结果:

2

注意： python2和python3的版本中print等函数语法可能不同：例如：print “hello”(python2)—>print(“hello”)(python3)

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