[转]Linux下Python与C++混合编程

转自：http://www.cnblogs.com/tevic/p/3645197.html 

最近在作一个CUDA的项目,记录下学习心得.

系统

Linux 3.11.0-19-generic #33-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,不然下面模块不能正常导入
    PyRun_SimpleString("import sys"); PyRun_SimpleString("sys.path.append('./')"); //引入模块
    PyRun_SimpleString("print('----------PyImport_ImportModule')"); PyObject *pModule = PyImport_ImportModule("TestModule"); //获取模块字典属性
    PyRun_SimpleString("print('----------PyModule_GetDict')"); PyObject *pDict = PyModule_GetDict(pModule); //直接获取模块中的函数
    PyRun_SimpleString("print('----------PyObject_GetAttrString')"); 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
    PyRun_SimpleString("print('----------Py_BuildValue')"); PyObject *pArg = Py_BuildValue("(s)", "Hello Charity"); PyRun_SimpleString("print('----------PyEval_CallObject')"); //调用直接得到的函数，并传递参数
 PyEval_CallObject(pFunc, pArg); //从字典属性中获取函数
    PyRun_SimpleString("print('----------PyDict_GetItemString Add function')"); 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，并获得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); //经过字典属性获取模块中的类
    PyRun_SimpleString("print('----------PyDict_GetItemString test class')"); PyObject *pClass = PyDict_GetItemString(pDict, "Test"); //实例化获取的类
    PyRun_SimpleString("print('----------PyInstanceMethod_New test class')"); PyObject *pInstance = PyInstanceMethod_New(pClass); //调用类的方法
    PyRun_SimpleString("print('----------PyObject_CallMethod SayHello')"); result = PyObject_CallMethod(pInstance, "SayHello", "(Os)", pInstance, "Charity"); //输出返回值
    char* name=NULL; PyRun_SimpleString("print('----------PyArg_Parse')"); 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/python3.5 pythonwithcpp.cpp -L/usr/lib/python3.5/config-3.5m-x86_64-linux-gnu -lpython3.5

运行结果:

root@ubuntu:/work/src/cython/cppcallpy# ./a.out
----------Python Start
----------PyImport_ImportModule
----------PyModule_GetDict
----------PyObject_GetAttrString
----------Py_BuildValue
----------PyEval_CallObject
Hello World
Hello Charity
----------PyDict_GetItemString Add function
a= 1
b= 2
a+b=3
----------PyDict_GetItemString test class
----------PyInstanceMethod_New test class
----------PyObject_CallMethod SayHello
Hello, Charity
----------PyArg_Parse
Charity
Python End

Python调用C++

C++代码:

1 //用C++必须在函数前加extern "C"
2 extern "C" int Add(int a,int b)
3 {
4     return a+b;
5 }

编译:

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

Python代码:

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

运行:

1 python PythonCallCpp.py

运行结果:

2