//创建一个event_base
struct event_base *base = event_base_new();
assert(base != NULL); 

 //创建并绑定一个event
struct event *listen_event;
//参数：event_base, 监听的fd，事件类型及属性，绑定的回调函数，给回调函数的参数
 
listen_event = event_new(base, listener, EV_READ | EV_PERSIST, callback_func, (void*)base);
//参数：event，超时时间(struct timeval *类型的，NULL表示无超时设置)
event_add(listen_event, NULL);

  #include <WinSock2.h>
  #include <stdlib.h>
  #include <stdio.h>
  #include <string.h>
  #include <errno.h>
  #include <event2/event.h>
  #include <event2/bufferevent.h>
  #include<iostream>
  #include<cassert>
  #pragma comment (lib,"ws2_32.lib")
  #include<ws2tcpip.h>
  #define LISTEN_PORT 9999
  #define LIATEN_BACKLOG 32
 using namespace std;
 /*********************************************************************************
 *                   函数声明
 **********************************************************************************/
 //accept回掉函数
 void do_accept_cb(evutil_socket_t listener, short event, void *arg);
 //read 回调函数
 void read_cb(struct bufferevent *bev, void *arg);
 //error回调函数
 void error_cb(struct bufferevent *bev, short event, void *arg);
 //write 回调函数
 void write_cb(struct bufferevent *bev, void *arg);
 /*********************************************************************************
 *                   函数体
 **********************************************************************************/
 //accept回掉函数
 void do_accept_cb(evutil_socket_t listener, short event, void *arg)
 {
   //传入的event_base指针
   struct event_base *base = (struct event_base*)arg;
   //socket描述符
   evutil_socket_t fd;
   //声明地址
   struct sockaddr_in sin;
   //地址长度声明
   socklen_t slen = sizeof(sin);
   //接收客户端
   fd = accept(listener, (struct sockaddr *)&sin, &slen);
   if (fd < 0)
   {
     perror("error accept");
     return;
   }
   printf("ACCEPT: fd = %un", fd);
   ////注册一个bufferevent_socket_new事件
   struct bufferevent *bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
   ////设置回掉函数
   bufferevent_setcb(bev, read_cb, NULL, error_cb, arg);
   ////设置该事件的属性
   bufferevent_enable(bev, EV_READ | EV_WRITE | EV_PERSIST);
 }
 ////read 回调函数
 void read_cb(struct bufferevent *bev, void *arg)
 {
 #define MAX_LINE 256
   char line[MAX_LINE + 1];
   int n;
   //通过传入参数bev找到socket fd
   evutil_socket_t fd = bufferevent_getfd(bev);
   //
   while (n = bufferevent_read(bev, line, MAX_LINE))
   {
     line[n] = '';
     printf("fd=%u, read line: %sn", fd, line);
     //将获取的数据返回给客户端
     bufferevent_write(bev, line, n);
   }
 }
 ////error回调函数
 void error_cb(struct bufferevent *bev, short event, void *arg)
 {
   //通过传入参数bev找到socket fd
   evutil_socket_t fd = bufferevent_getfd(bev);
   //cout << "fd = " << fd << endl;
   if (event & BEV_EVENT_TIMEOUT)
   {
     printf("Timed outn"); //if bufferevent_set_timeouts() called
   }
   else if (event & BEV_EVENT_EOF)
   {
     printf("connection closedn");
   }
   else if (event & BEV_EVENT_ERROR)
   {
     printf("some other errorn");
   }
   bufferevent_free(bev);
 }
 ////write 回调函数
 void write_cb(struct bufferevent *bev, void *arg)
 {
   char str[50];
   //通过传入参数bev找到socket fd
   evutil_socket_t fd = bufferevent_getfd(bev);
   //cin >> str;
   printf("输入数据！");
   scanf_s("%d", &str);
   bufferevent_write(bev, &str, sizeof(str));
 }
 
 int main()
 {
   int ret;
   evutil_socket_t listener;
   WSADATA Ws;
   //Init Windows Socket
   if (WSAStartup(MAKEWORD(2, 2), &Ws) != 0)
   {
     return -1;
   }
   listener = socket(AF_INET, SOCK_STREAM, 0);
   assert(listener > 0);
   evutil_make_listen_socket_reuseable(listener);
   struct sockaddr_in sin;
   sin.sin_family = AF_INET;
   sin.sin_addr.s_addr = 0;
   sin.sin_port = htons(LISTEN_PORT);
   if (bind(listener, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
     perror("bind");
     return 1;
   }
   if (listen(listener, 1000) < 0) {
     perror("listen");
     return 1;
   }
  printf("Listening...n");
   evutil_make_socket_nonblocking(listener);
   struct event_base *base = event_base_new();
   assert(base != NULL);
   struct event *listen_event;
   listen_event = event_new(base, listener, EV_READ | EV_PERSIST, do_accept_cb, (void*)base);
   event_add(listen_event, NULL);
   event_base_dispatch(base);
   printf("The End.");
   return 0;
 }

/******* 客户端程序 client.c ************/
#define _WINSOCK_DEPRECATED_NO_WARNINGS
#define _CRT_SECURE_NO_WARNINGS
#include <stdlib.h> 
#include <stdio.h> 
#include <errno.h> 
#include <string.h>    
#include<winsock2.h>
#include<ws2tcpip.h>
#include<iostream>
 
 #pragma comment (lib,"ws2_32.lib")
 int main(int argc, char *argv[])
 {
   WSADATA Ws;
   //Init Windows Socket
   if (WSAStartup(MAKEWORD(2, 2), &Ws) != 0)
   {
     return 0;
   }
   int sockfd;
   char buffer[1024];
   struct sockaddr_in server_addr;
   struct hostent *host;
   int portnumber, nbytes;
 
   if ((host = gethostbyname("127.0.0.1")) == NULL)
   {
     fprintf(stderr, "Gethostname errorn");
     exit(1);
   }
 
   if ((portnumber = atoi("9999"))<0)
   {
     fprintf(stderr, "Usage:%s hostname portnumberan", argv[0]);
     exit(1);
   }
 
   /* 客户程序开始建立 sockfd描述符 */
   if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
   {
     fprintf(stderr, "Socket Error:%san", strerror(errno));
     exit(1);
   }
 
   /* 客户程序填充服务端的资料    */
   memset(&server_addr,0, sizeof(server_addr));
   server_addr.sin_family = AF_INET;
   server_addr.sin_port = htons(portnumber);
   server_addr.sin_addr = *((struct in_addr *)host->h_addr);
 
   /* 客户程序发起连接请求     */
   if (connect(sockfd, (struct sockaddr *)(&server_addr), sizeof(struct sockaddr)) == -1)
  {
     fprintf(stderr, "Connect Error:%san", strerror(errno));
     exit(1);
   }
 
   while (true)
   {
     char MESSAGE[] = "hello server..n";
     //bufferevent_write(buf_ev,MESSAGE,strlen(MESSAGE)); 
     // 
     if (-1 == (::send(sockfd, MESSAGE, strlen(MESSAGE), 0)))
     {
       printf("the net has a error occured..");
       break;
     }
 
     if ((nbytes = recv(sockfd, buffer, 1024,0)) == -1)
    {
       fprintf(stderr, "read error:%sn", strerror(errno));
       exit(1);
     }
 
     buffer[nbytes] = '';
     printf("I have received:%sn", buffer);
     memset(buffer, 0, 1024);
 
     Sleep(2);
 
   }
   /* 结束通讯   */
   closesocket(sockfd);
   exit(0);
 
   return 0;
 }