python调用C++，传递结构体与结构体指针，以及嵌套结构体

#include<iostream>using namespace std;//该文件名称：cpptest.cpp//终端下编译指令：//g++ -o cpptest.so -shared -fPIC cpptest.cppstruct sub_struct{    char* test_char;    int test_int;};struct struct_def {    char* stru_string;    int stru_int;    char stru_arr_num[4];    sub_struct son_struct;};extern "C"{//在extern “C”中的函数才能被外部调用    int test(struct_def  struct_mystruct,struct_def* struct_test_p) {        //输出结构体指针的数据        cout<<"输出结构体中的char*字符:";        cout << struct_mystruct.stru_string << endl;        cout<<"输出结构体中的int型：";        cout << struct_mystruct.stru_int <<endl;        cout <<"输出结构体中的字符数组:";        for(int x = 0;x< 4;x++){cout << struct_mystruct.stru_arr_num[x]<<"   ";}        cout<< endl;        cout<<"输出子结构体中的char*型：";        cout << struct_mystruct.son_struct.test_char<<endl;        cout<<"输出子结构体中的int型：";        cout<<struct_mystruct.son_struct.test_int<<endl;        //输出结构体指针的数据        cout<<endl;        cout<<endl;         cout<<"输出结构体指针中的char*字符:";        cout << struct_test_p->stru_string << endl;        cout<<"输出结构体指针中的int型：";        cout << struct_test_p->stru_int <<endl;        cout <<"输出结构体指针中的字符数组:";        for(int x = 0;x< 4;x++){cout << struct_test_p->stru_arr_num[x]<<"   ";}        cout<< endl;        cout<<"输出子结构体指针中的字符串：";        cout<<struct_test_p->son_struct.test_char;        cout << endl;        cout<<"输出子结构体指针中的int型：";        cout<<struct_test_p->son_struct.test_int<<endl;    }}##python 文件##文件名  pytest.pyimport ctypesmylib = ctypes.cdll.LoadLibrary("cpptest.so")class sub_struct(ctypes.Structure):    _fields_ = [        ("test_char_p",ctypes.c_char_p),        ("test_int",ctypes.c_int)    ]class struct_def(ctypes.Structure):    _fields_ = [        ("stru_string",ctypes.c_char_p),        ("stru_int", ctypes.c_int),        ("stru_arr_num", ctypes.c_char*4),        ("son_struct", sub_struct)    ]struct_mystruct = struct_def()struct_mystruct.stru_string = b"string in the struct"struct_mystruct.stru_int = 99struct_mystruct.stru_arr_num = b"ABCD"struct_mystruct.son_struct.test_char_p =b"sub struct of the string"struct_mystruct.son_struct.test_int = 10mylib.test(struct_mystruct,ctypes.byref(struct_mystruct))