Libevent

一個(gè)事件集合struct event_base。

一個(gè)事件 struct event (io事件，定時(shí)器事件，信號(hào)事件)。

#include <stdio.h>
#include <stdlib.h>
#include <event.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <event2/listener.h>

//讀事件回調(diào)
void read_cb(struct bufferevent*bev,void *arg)
{
    int fd = *(int*)arg;
    char buf[128] = 0;
    int ret = bufferevent_read(bev, buf, sizeof(buf));
    if(ret < 0)
    {
        printf("read error\n");
    }
    else
    {
        printf("recv from %d:%s",fd,buf);
    }
}

//其他事件回調(diào)
void event_cb(struct bufferevent*bev,short what,void *arg)
{
    if(what &BEV_EVNET_EOF)
    {
        printf("客戶端下線\n");
        bufferevent_free(bev);      //釋放buffereven對(duì)象
    }
    else
    {
        printf("未知錯(cuò)誤");
    }
}

void listener_cb(struct evconnlistener*listener, evutil_socket_t fd,struct sockaddr*addr,int socklen, void *arg)
{
    printf("接受%d的連接\n"，fd);
    struct event_base *base = arg; //需要從主函數(shù)傳遞過來
    
    //針對(duì)已經(jīng)存在的socket創(chuàng)建bufferevent對(duì)象
    //參數(shù)如下：返回buffer對(duì)象
    struct bufferevent*bev = bufferevent_socket_new(base,   //事件集合
                           fd,      //文件描述符
                           BEV_OPT_CLOSE_ON_FREE //釋放bufferevent對(duì)象則斷開連接
                          );
    
    //給bufferevnet設(shè)置回調(diào)函數(shù)
    bufferevent_setcb(bev,          //buffereven對(duì)象
                      read_cb,      //讀回調(diào)
                      NULL,         //寫回調(diào)
                      event_cb,     //其他回調(diào)
                      (void*)fd;            //參數(shù)
    
    //使能事件類型
    bufferevent_enable(bev,     //buffereven對(duì)象
                       EV_READ      //使能讀
                      )
    
}


int main()
{
    //創(chuàng)建一個(gè)事件集合
    struct event_base *base = event_base_new();
    if(NULL==base)
    {
        exit(1);
    }
    //創(chuàng)建監(jiān)聽對(duì)象
    struct sockaddr_in server_addr;
    memset(&server_addr, 0 ,sizeof(server_addr));
    server_addr.sin_port = 8000;
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    
    //一步完成:創(chuàng)建socket 綁定socket,監(jiān)聽，接受鏈接四部
    //參數(shù)如下：
    struct evconnlistener *listener = evconnlistener_new_bind(base,         //事件集合
                            listener_cb,                    //當(dāng)有鏈接時(shí)調(diào)用的函數(shù)
                            NULL,                           //回調(diào)函數(shù)的參數(shù)
                            LEV_OPT_CLOSE_ON_FREE | LEV_OPT_REUSEABLE,
                            10,                             //監(jiān)聽隊(duì)列的長度
                            (struct sockaddr*)&server_addr, //tcp綁定信息
                            sizeof(server_addr)             //tcp信息的大小
                           );
    if(NULL == listener)
    {
        exit(1);
    }
    //監(jiān)聽集合中的事件
    event_base_dispatch(base);
    
    //釋放兩個(gè)對(duì)象
    evconnlistener_free(listener);      //連接對(duì)象    
    event_base_free(base);              //釋放集合
    
}