-
Windows 系统中，在 Visual Studio 中新建一个动态链接库项目，本文将其命名为
lib4py，然后新建lib4py.h和lib4py.cpp两个文件。 - Linux 系统中，新建一个文件夹然后在文件夹中新建如上的两个文件。
动态链接库部分
lib4py.h 文件
#ifdef LIB4PY_EXPORTS
#define LIB4PY_API __declspec(dllexport)
#else
#define LIB4PY_API __declspec(dllimport)
#endif
extern "C"
{
struct LIB4PY_API Person {
char *name;
int age;
double *scores;
int n_subjects;
};
struct LIB4PY_API Matrix {
double **mat;
int row;
int col;
};
LIB4PY_API void print_info(Person *p);
LIB4PY_API void print_mat(double **mat, int row, int col);
LIB4PY_API Matrix* gen_mat(double **mat, int row, int col);
LIB4PY_API void print_matrix(Matrix* m);
LIB4PY_API void print_arr(double* arr, int n);
}
lib4py.cpp 文件
#include "lib4py.h"
#include <iostream>
#include <cstdlib>
using namespace std;
LIB4PY_API void print_info(Person *p) {
cout << "Name: " << p->name << "\n" << "Age: " << p->age << "\n" << "scores: ";
for (int i = 0; i < p->n_subjects; ++i)
cout << p->scores[i] << " ";
cout << endl;
}
LIB4PY_API void print_mat(double **mat, int row, int col) {
for (int i = 0; i < row; ++i) {
for (int j = 0; j < col; ++j)
cout << mat[i][j] << " ";
cout << endl;
}
}
LIB4PY_API Matrix* gen_mat(double **mat, int row, int col) {
Matrix *m = (Matrix *)malloc(sizeof(Matrix));
m->row = row;
m->col = col;
m->mat = mat;
return m;
}
LIB4PY_API void print_matrix(Matrix* m) {
for (int i = 0; i < m->row; ++i) {
for (int j = 0; j < m->col; ++j)
cout << m->mat[i][j] << " ";
cout << endl;
}
}
LIB4PY_API void print_arr(double* arr, int n) {
for (int i = 0; i < n; ++i)
cout << arr[i] << " ";
cout << endl;
}
- 在 Windows 系统中，直接编译后生成
lib4py.dll。 - 在 Linux 系统中，输入
命令生成g++ lib4py.cpp lib4py.h -fPIC -shared -o lib4py.solib4py.so文件。
然后在同文件夹下建立如下 Python 文件
Python 部分
from ctypes import *
import sys
# 加载动态链接库
if sys.platform == 'win32':
_dll = CDLL("lib4py.dll")
else:
_dll = CDLL("lib4py.so")
# 设置C函数的返回值类型和参数类型（如果类型是基本类型则不用调用该函数）
def fillprototype(f, restype, argtypes):
f.restype = restype
f.argtypes = argtypes
# 测试结构体
class Person(Structure):
_fields_ = [("name", c_char_p),
("age", c_int),
("scores", POINTER(c_double)),
("n_subjects", c_int)]
class Matrix(Structure):
_fields_ = [("mat", POINTER(POINTER(c_double))),
("row", c_int),
("col", c_int)]
def __str__(self):
return f"<Matrix row: {self.row}, col: {self.col}>"
# 一维数组
scores = (c_double * 5)(1, 2, 3, 4, 5)
print('Test array:')
_dll.print_arr(scores, 5)
print('Test 2-D array:')
arr1 = (c_double * 5)(1, 2, 3, 4, 5)
arr2 = (c_double * 5)(1, 2, 3, 4, 5)
# 二维数组
mat = (POINTER(c_double) * 2)(arr1, arr2)
_dll.print_mat(mat, 2, 5)
print('Test struct as args:')
p = Person(c_char_p(b"Liu"), 20, scores, 5)
_dll.print_info(byref(p))
matrix = Matrix(mat, 2, 5)
_dll.print_matrix(byref(matrix))
print('Test struct as return value:')
fillprototype(_dll.gen_mat, POINTER(Matrix), [POINTER(POINTER(c_double)), c_int, c_int])
matrix_p = _dll.gen_mat(mat, 2, 5)
print(matrix_p.contents)
输出
Test array:
1 2 3 4 5
Test 2-D array:
1 2 3 4 5
1 2 3 4 5
Test struct as args:
Name: Liu
Age: 20
scores: 1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
Test struct as return value:
<Matrix row: 2, col: 5>
