2、node-ffi

1）nodejs從c語言讀取數據

factorial.c

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>

#if defined(WIN32) || defined(_WIN32)
#define EXPORT __declspec(dllexport)
#else
#define EXPORT
#endif

typedef 
 
struct
{
    double lon;
    double lat;
}gps_info_t;

gps_info_t* gps;

void get_gps_shm_init(void)
{
    gps = (gps_info_t *)malloc(sizeof(gps_info_t));
}

EXPORT gps_info_t* get_gps_info(void) {
  get_gps_shm_init();
  gps->lon = 55.5;
  gps->lat = 55.5;return gps;
}

factorial.js

var ffi = require(‘../node-ffi-master/‘)
var refStruct = require(‘ref-struct‘);
var refArray = require(‘ref-array‘);
var ref = require(‘ref‘);

//gps date struct
var gps = refStruct({
    ‘lon‘:ref.types.double,
    ‘lat‘:ref.types.double,
});

var gpsStructArrayType = refArray(gps);
var
 
 gps_info = gpsStructArrayType(10);

var libfactorial = ffi.Library(‘./libfactorial‘, {
  ‘get_gps_info‘: [ gpsStructArrayType, [ ‘void‘ ] ],
});

gps_info = libfactorial.get_gps_info(0)

console.log(‘Your output: ‘ + gps_info[0].lon)
console.log(‘Your output: ‘ + gps_info[0].lat)

2）nodejs向c語言寫數據

factorial.c

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>

#if defined(WIN32) || defined(_WIN32)
#define EXPORT __declspec(dllexport)
#else
#define EXPORT
#endif

typedef struct
{
    char *user_name;
    char *passwd;
    char *dev_id;
}user_info_t;

user_info_t* user;

void put_user_info_shm_init(void)
{
    user = (user_info_t *)malloc(sizeof(user_info_t));
    user->user_name = (char*)malloc(32*sizeof(char));
    user->passwd = (char*)malloc(32*sizeof(char));
    user->dev_id = (char*)malloc(32*sizeof(char));
}

EXPORT void put_user_info(user_info_t* user_info) {
  put_user_info_shm_init();
  printf("get userinfo(user_name):%s",user_info->user_name);
  printf("get userinfo(user_name):%s",user_info->passwd);
  printf("get userinfo(user_name):%s",user_info->dev_id);
}

factorial.js

var ffi = require(‘../node-ffi-master/‘)
var refStruct = require(‘ref-struct‘);
var refArray = require(‘ref-array‘);
var ref = require(‘ref‘);

//ui date struct
var user = refStruct({
    ‘user_name‘:‘string‘,
    ‘passwd‘:‘string‘,
    ‘dev_id‘:‘string‘,
});

var userStructArrayType = refArray(user);
var user_info = userStructArrayType(1);

user_info[0].user_name = ‘zdd‘;
user_info[0].passwd = ‘123‘;
user_info[0].dev_id = ‘65535‘;

var libfactorial = ffi.Library(‘./libfactorial‘, {
  ‘put_user_info‘: [ ‘void‘, [ userStructArrayType ] ]
});

libfactorial.put_user_info(user_info)

console.log(‘Your input: ‘ + user_info[0].user_name)
console.log(‘Your input: ‘ + user_info[0].passwd)
console.log(‘Your input: ‘ + user_info[0].dev_id)

nodejs與c語言深度交互