python中使用動態庫

首先，建立一個簡單的動態庫
編程產生dll.so:   gcc -fPIC -O2 -shared dll.c -o dll.so
C檔案:dll.c  如下

#include <stdio.h>

struct param {
int a;
int b;
char c;
float f;
int arr[3];
    };

void print0(struct param arg)
{
    printf("in print:\n");
    printf("a: %d\n", arg.a);
    printf("b: %d\n", arg.b);
    printf("c: %c\n", arg.c);
    printf("f: %f\n", arg.f);
    printf("arr: %d  %d  %d\n", arg.arr[0], arg.arr[1], arg.arr[2]);
}

void print2(struct param *arg)
{
    printf("in print2 :\n");
    printf("a: %d\n", arg->a);
    printf("b: %d\n", arg->b);
    printf("c: %c\n", arg->c);
    printf("f: %f\n", arg->f);
    printf("arr: %d  %d  %d\n", arg->arr[0], arg->arr[1], arg->arr[2]);
}

void print3(int a)
{
    printf("in print3:\n");
    printf("a: %d\n", a);
}

python定義傳給動態庫的結構體

from ctypes import *

class ss(Structure):
    _fields_ = [
    ("a", c_int),
    ("b", c_int),
    ("c", c_char),
    ("f", c_float),
    ("arr", c_int*3),  //定義數組
    ]

python 使用dll.so執行個體

#載入動態庫
fileName = "/home/primax/Desktop/Work/Test/python/dll.so"
lib = cdll.LoadLibrary(fileName)
#定義變數
param = ss()
#給結構體賦值
param.a = 1
param.b = 2
param.c = 'a'
param.f = 1.2345
param.arr[0] = 0
param.arr[1] = 1
param.arr[2] = 2

lib.print0(param)
lib.print3(2)
#傳指標 pointer取指標
lib.print2(pointer(param))