C++调用Python

python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
    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')");
    //调用直接获得的函数，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
    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：
(依据自己系统python路径修改）

g++ $(/usr/bin/python3.5-config --cflags) pythonwithcpp.cpp $(/usr/bin/python3.5-config --ldflags)) -lpython3.5

---

编译2：
若是使用anaconda中的python解释器：

g++ $(/home/hove/anaconda3/envs/evo/bin/python3.8-config --cflags) pythonwithcpp.cpp -o b.out $(/home/hove/anaconda3/envs/evo/bin/python3.8-config  --ldflags) -lpython3.8

同时导入anaconda的动态库：

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/hove/anaconda3/envs/evo/lib

运行结果：

 ./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

参考：

1. https://docs.python.org/3/extending/embedding.html
2. https://www.cnblogs.com/xuyuan77/p/8419442.html
3. https://stackoverflow.com/questions/43333207/python-error-while-loading-shared-libraries-libpython3-4m-so-1-0-cannot-open
4. 官方文档：https://docs.python.org/3/c-api/index.html