epoll使用的一个小例子,非常实用

    技术2022-05-11  66

    #define MAXLINE 10#define OPEN_MAX 100#define LISTENQ 20#define SERV_PORT 5555#define INFTIM 1000

    //线程池任务队列结构体struct task{  int fd;            //需要读写的文件描述符  struct task *next; //下一个任务};

     

    //用于读写两个的两个方面传递参数struct user_data{  int fd;  unsigned int n_size;  char line[MAXLINE];};

     

    //线程的任务函数void * readtask(void *args);void * writetask(void *args);

     

     

    //声明epoll_event结构体的变量,ev用于注册事件,数组用于回传要处理的事件struct epoll_event ev,events[20];int epfd;pthread_mutex_t mutex;pthread_cond_t cond1;struct task *readhead=NULL,*readtail=NULL,*writehead=NULL;

    void setnonblocking(int sock){     int opts;     opts=fcntl(sock,F_GETFL);     if(opts<0)     {          perror("fcntl(sock,GETFL)");          exit(1);     }     opts = opts|O_NONBLOCK;     if(fcntl(sock,F_SETFL,opts)<0)     {          perror("fcntl(sock,SETFL,opts)");          exit(1);     }    }

    int main(){     int i, maxi, listenfd, connfd, sockfd,nfds;     pthread_t tid1,tid2;     struct task *new_task=NULL;     struct user_data *rdata=NULL;     socklen_t clilen;

         pthread_mutex_init(&mutex,NULL);     pthread_cond_init(&cond1,NULL);

         //初始化用于读线程池的线程     pthread_create(&tid1,NULL,readtask,NULL);     pthread_create(&tid2,NULL,readtask,NULL);

         //生成用于处理accept的epoll专用的文件描述符         epfd=epoll_create(256);     struct sockaddr_in clientaddr;     struct sockaddr_in serveraddr;     listenfd = socket(AF_INET, SOCK_STREAM, 0);     //把socket设置为非阻塞方式     setnonblocking(listenfd);     //设置与要处理的事件相关的文件描述符     ev.data.fd=listenfd;     //设置要处理的事件类型     ev.events=EPOLLIN|EPOLLET;     //注册epoll事件     epoll_ctl(epfd,EPOLL_CTL_ADD,listenfd,&ev);

         bzero(&serveraddr, sizeof(serveraddr));     serveraddr.sin_family = AF_INET;

         char *local_addr="200.200.200.222";     inet_aton(local_addr,&(serveraddr.sin_addr));//htons(SERV_PORT);     serveraddr.sin_port=htons(SERV_PORT);     bind(listenfd,(sockaddr *)&serveraddr, sizeof(serveraddr));     listen(listenfd, LISTENQ);

         maxi = 0;      for ( ; ; ) {          //等待epoll事件的发生          nfds=epoll_wait(epfd,events,20,500);          //处理所发生的所有事件              for(i=0;i<nfds;i++)         {               if(events[i].data.fd==listenfd)               {                    connfd = accept(listenfd,(sockaddr *)&clientaddr, &clilen);                    if(connfd<0){                      perror("connfd<0");                      exit(1);                   }                    setnonblocking(connfd);

                        char *str = inet_ntoa(clientaddr.sin_addr);                    std::cout<<"connec_ from >>"<                     //设置用于读操作的文件描述符                    ev.data.fd=connfd;                    //设置用于注测的读操作事件                 ev.events=EPOLLIN|EPOLLET;                    //注册ev                 epoll_ctl(epfd,EPOLL_CTL_ADD,connfd,&ev);               }            else if(events[i].events&EPOLLIN)            {                    printf("reading!/n");                                     if ( (sockfd = events[i].data.fd) < 0) continue;                    new_task=new task();                    new_task->fd=sockfd;                    new_task->next=NULL;                    //添加新的读任务                    pthread_mutex_lock(&mutex);                    if(readhead==NULL)                    {                      readhead=new_task;                      readtail=new_task;                    }                        else                    {                         readtail->next=new_task;                      readtail=new_task;                    }                       //唤醒所有等待cond1条件的线程                    pthread_cond_broadcast(&cond1);                    pthread_mutex_unlock(&mutex);                }               else if(events[i].events&EPOLLOUT)               {                  rdata=(struct user_data *)events[i].data.ptr;                 sockfd = rdata->fd;                 write(sockfd, rdata->line, rdata->n_size);                 delete rdata;                 //设置用于读操作的文件描述符                 ev.data.fd=sockfd;

                   //设置用于注测的读操作事件               ev.events=EPOLLIN|EPOLLET;                 //修改sockfd上要处理的事件为EPOLIN               epoll_ctl(epfd,EPOLL_CTL_MOD,sockfd,&ev);               }          }     }}

    void * readtask(void *args){   int fd=-1;   unsigned int n;   //用于把读出来的数据传递出去   struct user_data *data = NULL;   while(1){        pthread_mutex_lock(&mutex);        //等待到任务队列不为空        while(readhead==NULL)             pthread_cond_wait(&cond1,&mutex);        fd=readhead->fd;        //从任务队列取出一个读任务        struct task *tmp=readhead;        readhead = readhead->next;        delete tmp;        pthread_mutex_unlock(&mutex);        data = new user_data();        data->fd=fd;        if ( (n = read(fd, data->line, MAXLINE)) < 0) {           if (errno == ECONNRESET) {             close(fd);          } else              std::cout<<"readline error"<            if(data!=NULL)delete data;        } else if (n == 0) {            close(fd);           printf("Client close connect!/n");           if(data!=NULL)delete data;        } else{        data->n_size=n;        //设置需要传递出去的数据        ev.data.ptr=data;        //设置用于注测的写操作事件        ev.events=EPOLLOUT|EPOLLET;        //修改sockfd上要处理的事件为EPOLLOUT        epoll_ctl(epfd,EPOLL_CTL_MOD,fd,&ev);       }   }}

     

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