使用bufferevent进行libevent服务端和客户端的开发

#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>

#include <stdio.h>
#include <string.h>

#include <event.h>
#include <event2/listener.h>
#include <event2/bufferevent.h>
#include <event2/thread.h>

using namespace std;

void listener_cb(evconnlistener *listener, evutil_socket_t fd,
         sockaddr *sock, int socklen, void *arg);

void socket_read_cb(bufferevent *bev, void *arg);

void socket_event_cb(bufferevent *bev, short events, void *arg);

int main(int argc, char **argv) {

    sockaddr_in sin;
    memset(&sin, 0, sizeof(sockaddr_in));
    sin.sin_family = AF_INET;
    sin.sin_port = htons(8899);

    event_base *base = event_base_new();
    evconnlistener *listener
        = evconnlistener_new_bind(base,
                      listener_cb, base,
                      LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE,
                      10, (sockaddr*)&sin, sizeof(sockaddr_in));

    event_base_dispatch(base);

    evconnlistener_free(listener);
    event_base_free(base);

}

void listener_cb(evconnlistener *listener, evutil_socket_t fd,
        sockaddr *sock, int socklen, void *arg) {

    printf("accept a client %d
", fd);
    event_base *base = (event_base *) arg;

    bufferevent *bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);

    bufferevent_setcb(bev, socket_read_cb, NULL, socket_event_cb, NULL);
    bufferevent_enable(bev, EV_READ | EV_PERSIST);

}


void socket_read_cb(bufferevent *bev, void *arg) {
    char msg[4096];
    size_t len = bufferevent_read(bev, msg, sizeof(msg) - 1);

    msg[len] = '