client端:

#include <event2/event.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <event2/bufferevent.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <event2/listener.h>
#include <event2/dns.h>
#include <stdlib.h>
#include <event2/util.h>

//read write callback
void readcb(struct bufferevent *bev, void *ctx){
  char buf[64];
  size_t ret = bufferevent_read(bev, buf, sizeof(buf));
  buf[ret] = '\0';
  printf("client recf:%s\n", buf);

}

//event callback
void eventcb(struct bufferevent *bev, short what, void *ctx){
  if(what & BEV_EVENT_CONNECTED){
    printf("connect okay\n");  
  }
  else if(what & BEV_EVENT_ERROR){
    struct event_base* base = ctx;
    int err = bufferevent_socket_get_dns_error(bev);
    if(err){
      printf("DNS error:%s\n", evutil_gai_strerror(err));
    }
    printf("closing\n");
    bufferevent_free(bev);
    event_base_loopexit(base, NULL);
  }
}

//terminal read callback
void termicb(evutil_socket_t fd, short what, void* ptr){
  char buf[64] = {0};
  int len = read(fd, buf, sizeof(buf));
  buf[len] = '\0';
  printf("in termicb\n");
  struct bufferevent* bev = ptr;
  bufferevent_write(bev, buf, len);
}
int main(int artc, char** argv){

  struct event_base* base;
  base = event_base_new();
 
  struct evdns_base* dns_base;
  dns_base = evdns_base_new(base, 1);

  struct bufferevent* bev;
  bev = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);

  int port = atoi(argv[2]);
  bufferevent_setcb(bev, readcb, NULL, eventcb, base);
  bufferevent_enable(bev, EV_READ);
  bufferevent_socket_connect_hostname(bev, dns_base, AF_INET, argv[1], port);

  struct event* ev = event_new(base, STDIN_FILENO, EV_READ | EV_PERSIST, termicb, bev);
  event_add(ev, NULL);
  event_base_dispatch(base);
  event_base_free(base);
}