Linux下Python与C++混合编程

最近在做一个CUDA的项目,记录下学习心得.

系统

Linux 3.11.--generic #-Ubuntu x86_64 GNU/Linux

C++调用Python

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)", , );

     //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 ;
 }

编译:

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

运行结果:

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

Python调用C++

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:

 python PythonCallCpp.py

运行结果: