[转]Linux下Python与C++混合编程

Posted 2020-10-23 XY

最近在做一个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:

 1 #!/usr/bin/python
 2 #Filename:TestModule.py
 3 def Hello(s):
 4     print "Hello World"
 5     print s
 6 
 7 def Add(a, b):
 8     print ‘a=‘, a
 9     print ‘b=‘, b
10     return a + b
11 
12 class Test:
13     def __init__(self):
14         print "Init"
15     def SayHello(self, name):
16         print "Hello,", name
17         return name

C++代码:

 1 #include<iostream>
 2 #include<Python.h>
 3 using namespace std;
 4 int main(int argc, char* argv[])
 5 {
 6     //初始化python
 7     Py_Initialize();
 8 
 9     //直接运行python代码
10     PyRun_SimpleString("print ‘Python Start‘");
11 
12     //引入当前路径,否则下面模块不能正常导入
13     PyRun_SimpleString("import sys");  
14     PyRun_SimpleString("sys.path.append(‘./‘)");  
15 
16     //引入模块
17     PyObject *pModule = PyImport_ImportModule("TestModule");
18     //获取模块字典属性
19     PyObject *pDict = PyModule_GetDict(pModule);
20 
21     //直接获取模块中的函数
22     PyObject *pFunc = PyObject_GetAttrString(pModule, "Hello");
23 
24     //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
25     PyObject *pArg = Py_BuildValue("(s)", "Hello Charity");
26 
27     //调用直接获得的函数，并传递参数
28     PyEval_CallObject(pFunc, pArg);
29 
30     //从字典属性中获取函数
31     pFunc = PyDict_GetItemString(pDict, "Add");
32     //参数类型转换，传递两个整型参数
33     pArg = Py_BuildValue("(i, i)", 1, 2);
34 
35     //调用函数，并得到python类型的返回值
36     PyObject *result = PyEval_CallObject(pFunc, pArg);
37     //c用来保存c/c++类型的返回值
38     int c;
39     //将python类型的返回值转换为c/c++类型
40     PyArg_Parse(result, "i", &c);
41     //输出返回值
42     printf("a+b=%d\n", c);
43 
44     //通过字典属性获取模块中的类
45     PyObject *pClass = PyDict_GetItemString(pDict, "Test");
46 
47     //实例化获取的类
48     PyObject *pInstance = PyInstance_New(pClass, NULL, NULL);
49     //调用类的方法
50     result = PyObject_CallMethod(pInstance, "SayHello", "(s)", "Charity");
51     //输出返回值
52     char* name=NULL;
53     PyArg_Parse(result, "s", &name);
54     printf("%s\n", name);
55 
56     PyRun_SimpleString("print ‘Python End‘");
57 
58     //释放python
59     Py_Finalize();
60     getchar();
61     return 0;
62 }

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

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