Ubuntu下Python与C/C++混合编程(详细教程)

谁践踏了优雅 2022-12-28 15:29 267阅读 0赞

说明:测试环境为ubuntu18.04,使用语言Python3,C++. 由于python中无法定义(short)类型,或者(int)类型,所以使用Python调用C++的方法,在C++中计算,然后用Python调用.

## 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)", 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

--------------------

## Python调用C++ ##

C++代码:

#include<iostream>
    
    // //用C++必须在函数前加extern "C"
    //  extern "C" int Add(int a,int b)
    // {
    //      return a+b;
    // }
    
    
    //用C++必须在函数前加extern "C"
     extern "C" int data_type(int a,int b)
    {
         
         return (short)((a << 8)| b);
    }

编译:

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

Python代码:

#!/bin/python3
    #Filename:PythonCallCpp.py
    from ctypes import *
    import os
    # libPythonTest = cdll.LoadLibrary('./LibPythonTest.so')
    # print(libPythonTest.Add(1,1))
    
    libPythonTest = cdll.LoadLibrary('./LibPythonTest.so')
    print(libPythonTest.data_type(0xFD,0x78))

运行:

python PythonCallCpp.py

运行结果:

-648

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**注意： 上述方法在Python3中仍然适用.**

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