libevent 学习笔记

#include "event2/listener.h"
#include 
#include 
#include 
#include 
#include 
//回调函数 
void listencallback(struct evconnlistener *a1, evutil_socket_t fd, struct sockaddr *addr, int  socklen,void *arg)
{
     
    printf("callbcak\n");
}
int main(int argc, char *argv[])
{
     

    /*socket bind listen accept*/
    //用 evconnlistener_new_bind一步到位
    /*
      //配置参数
  * struct evconnlistener *evconnlistener_new_bind(struct event_base *base,
    evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
    const struct sockaddr *sa, int socklen);*/
    
    struct event_base *base=event_base_new(); // chuang jian ji he
    if(base==NULL)
    {
     
        perror("base create error");
        exit(1);
    }
    
    //   evconnlistener_cb cb  ----------- 当一个新的连接到达就会调用回调函数
    // void *ptr -----回调函数的参数
    //unsigned flags ------------默认为NULL
    //  LEV_OPT_LEAVE_SOCKETS_BLOCKING  阻塞等待
    //LEV_OPT_CLOSE_ON_FREE  释放监听对象的时候关闭sokcet 
    //  LEV_OPT_REUSEABLE socket 关闭的时候端口可以重复使用 
    //int backlog----监听队列长度
    struct sockaddr_in server;
    memset(&server,0,sizeof(server));
    server.sin_port=ntohs(8888);
    server.sin_addr.s_addr=inet_addr("127.0.0.1");
    server.sin_family=AF_INET;
    //释放监听对象关闭soket |端口重复使用
    //sockt fd 会加到集合base中去 
    struct evconnlistener *evlisten=evconnlistener_new_bind(base,listencallback,
                                                            NULL,LEV_OPT_CLOSE_ON_FREE|LEV_OPT_REUSEABLE,10,(struct sockaddr*)&server,sizeof(server));
    if(evlisten==NULL)
    {
     
        perror("evconnlistener_new_bind error");
        exit(1);
    }
    printf(" accept success\n");
    
    //监听
    event_base_dispatch(base);
    
    // 释放 对象
    evconnlistener_free(evlisten);
    //释放集合
    event_base_free(base);
    
    
    return 0;
}

#include "event2/listener.h"
#include 
#include 
#include 
#include 
#include 
#include "event2/bufferevent.h"
//回调函数

//typedef void (*bufferevent_data_cb)(struct bufferevent *bev, void *ctx);
void write_cb(struct bufferevent *bev, void *ctx)
{
     
    char buf[128];
   fgets(buf,sizeof(buf),stdin);
   int ret=bufferevent_write(bev,buf,strlen(buf));
            if(ret==0)
            {
     
                printf("write success\n");
            }

}

void read_cb(struct bufferevent *bev, void *ctx)  //  @return 0 if successful, or -1 if an error occurred.

{
     
    char buf[128]={
     0};
    int fd=*(int *)ctx;
  size_t ret=bufferevent_read(bev,buf,sizeof(buf));
  if(ret<0)
  {
     
      perror("read error");
      exit(1);
  }else printf("read from %d data: %s",fd,buf);
}
//有异常发生的回调函数
//typedef void (*bufferevent_event_cb)(struct bufferevent *bev, short what, void *ctx);
void event_cb(struct bufferevent *bev, short what, void *ctx)
{
     
    printf("what!!! %x\n",what);
    if(what&BEV_EVENT_EOF)
    {
     
       printf("客户端%d下线\n",*(int *)ctx);
       bufferevent_free(bev);//释放bufferevent 对象
    }else
    {
     
        printf("未知错误\n");
    }

}
void listencallback(struct evconnlistener *evlisten, evutil_socket_t fd, struct sockaddr *addr, int  socklen,void *arg)
{
     
    printf("callbcak\n");
    //针对 异常存在的 sockket创建 bufferevent 对象

/*struct bufferevent *bufferevent_socket_new(struct event_base *base,
 * evutil_socket_t fd, int options);
  */
    struct event_base *base =arg;
//如果bufferevent 对象 被释放 就关闭文件描述符
    // BEV_OPT_CLOSE_ON_FREE  ruguo bufferevent dui xiang bei shifang jiu guan bi wen jian miao shu fu
    //BEV_OPT_THREADSAFE
    //BEV_OPT_DEFER_CALLBACKS
    //BEV_OPT_UNLOCK_CALLBACKS
    struct bufferevent *bufferev=bufferevent_socket_new(base, fd,BEV_OPT_CLOSE_ON_FREE );
    if(bufferev==NULL) {
     
        perror("bufferevent_socket_new error");
        exit(1);
    }

    //bufferevent 设置回调函数
    /*
  void bufferevent_setcb(struct bufferevent *bufev,
    bufferevent_data_cb readcb, ke du
bufferevent_data_cb writecb,  ke xie
    bufferevent_event_cb eventcb, yichang
void *cbarg);chuan canshu
*/
    bufferevent_setcb(bufferev,read_cb,write_cb,event_cb,&fd);

    //使能bufferevent对象
    bufferevent_enable(bufferev,EV_READ|EV_WRITE);


}


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

    /*socket bind listen accept*/
    //用 evconnlistener_new_bind一步到位
    struct event_base *base=event_base_new(); //创建时间集合
    if(base==NULL)
    {
     
        perror("base create error");
        exit(1);
    }

    //   evconnlistener_cb cb  ----------- 当一个新的连接到达就会调用回调函数
    // void *ptr -----回调函数的参数
    //unsigned flags ------------默认为NULL
    //  LEV_OPT_LEAVE_SOCKETS_BLOCKING  阻塞等待
    //LEV_OPT_CLOSE_ON_FREE  释放监听对象的时候关闭sokcet
    //  LEV_OPT_REUSEABLE socket 关闭的时候端口可以重复使用
    //int backlog----监听队列长度
    struct sockaddr_in server;
    memset(&server,0,sizeof(server));
    server.sin_port=ntohs(8888);
    server.sin_addr.s_addr=inet_addr("127.0.0.1");
    server.sin_family=AF_INET;
    //释放监听对象关闭soket |端口重复使用
    //sockt fd 会加到集合base中去
    struct evconnlistener *evlisten=evconnlistener_new_bind(base,listencallback,
                                                            base,LEV_OPT_CLOSE_ON_FREE|LEV_OPT_REUSEABLE,10,(struct sockaddr*)&server,sizeof(server));
    if(evlisten==NULL)
    {
     
        perror("evconnlistener_new_bind error");
        exit(1);
    }

    printf(" accept success\n");

    //监听
    event_base_dispatch(base);

    // 释放 对象
    evconnlistener_free(evlisten);
    //释放集合
    event_base_free(base);


    return 0;
}