struct eventpoll{ .... /*紅黑樹的根節(jié)點，這顆樹中存儲著所有添加到epoll中的需要監(jiān)控的事件*/ struct rb_root rbr; /*雙鏈表中則存放著將要通過epoll_wait返回給用戶的滿足條件的事件*/ struct list_head rdlist; ....};

struct epitem{ struct rb_node rbn;//紅黑樹節(jié)點 struct list_head rdllink;//雙向鏈表節(jié)點 struct epoll_filefd ffd; //事件句柄信息 struct eventpoll *ep; //指向其所屬的eventpoll對象 struct epoll_event event; //期待發(fā)生的事件類型}

typedef union epoll_data { void *ptr; int fd; __uint32_t u32; __uint64_t u64; } epoll_data_t; struct epoll_event { __uint32_t events; /* Epoll events */ epoll_data_t data; /* User data variable */ }; 

struct epoll_event ev;//設置與要處理的事件相關的文件描述符ev.data.fd=listenfd;//設置要處理的事件類型ev.events=EPOLLIN|EPOLLET;//注冊epoll事件epoll_ctl(epfd,EPOLL_CTL_ADD,listenfd,&ev);

/** file epollTest.c*/#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <errno.h> #include <sys/socket.h> #include <netdb.h> #include <fcntl.h> #include <sys/epoll.h> #include <string.h> #define MAXEVENTS 64 //函數: //功能:創(chuàng)建和綁定一個TCP socket //參數:端口 //返回值:創(chuàng)建的socket static int create_and_bind (char *port) {  struct addrinfo hints;  struct addrinfo *result, *rp;  int s, sfd;  memset (&hints, 0, sizeof (struct addrinfo));  hints.ai_family = AF_UNSPEC;  /* Return IPv4 and IPv6 choices */  hints.ai_socktype = SOCK_STREAM; /* We want a TCP socket */  hints.ai_flags = AI_PASSIVE;  /* All interfaces */  s = getaddrinfo (NULL, port, &hints, &result);  if (s != 0)  {   fprintf (stderr, "getaddrinfo: %s/n", gai_strerror (s));   return -1;  }  for (rp = result; rp != NULL; rp = rp->ai_next)  {   sfd = socket (rp->ai_family, rp->ai_socktype, rp->ai_protocol);   if (sfd == -1)   continue;   s = bind (sfd, rp->ai_addr, rp->ai_addrlen);   if (s == 0)   {    /* We managed to bind successfully! */    break;   }   close (sfd);  }  if (rp == NULL)  {   fprintf (stderr, "Could not bind/n");   return -1;  }  freeaddrinfo (result);  return sfd; } //函數 //功能:設置socket為非阻塞的 static int make_socket_non_blocking (int sfd) {  int flags, s;  //得到文件狀態(tài)標志  flags = fcntl (sfd, F_GETFL, 0);  if (flags == -1)  {   perror ("fcntl");   return -1;  }  //設置文件狀態(tài)標志  flags |= O_NONBLOCK;  s = fcntl (sfd, F_SETFL, flags);  if (s == -1)  {   perror ("fcntl");   return -1;  }  return 0; } //端口由參數argv[1]指定 int main (int argc, char *argv[]) {  int sfd, s;  int efd;  struct epoll_event event;  struct epoll_event *events;  if (argc != 2)  {   fprintf (stderr, "Usage: %s [port]/n", argv[0]);   exit (EXIT_FAILURE);  }  sfd = create_and_bind (argv[1]);  if (sfd == -1)  abort ();  s = make_socket_non_blocking (sfd);  if (s == -1)  abort ();  s = listen (sfd, SOMAXCONN);  if (s == -1)  {   perror ("listen");   abort ();  }  //除了參數size被忽略外,此函數和epoll_create完全相同  efd = epoll_create1 (0);  if (efd == -1)  {   perror ("epoll_create");   abort ();  }  event.data.fd = sfd;  event.events = EPOLLIN | EPOLLET;//讀入,邊緣觸發(fā)方式  s = epoll_ctl (efd, EPOLL_CTL_ADD, sfd, &event);  if (s == -1)  {   perror ("epoll_ctl");   abort ();  }  /* Buffer where events are returned */  events = calloc (MAXEVENTS, sizeof event);  /* The event loop */  while (1)  {   int n, i;   n = epoll_wait (efd, events, MAXEVENTS, -1);   for (i = 0; i < n; i++)   {    if ((events[i].events & EPOLLERR) ||     (events[i].events & EPOLLHUP) ||     (!(events[i].events & EPOLLIN)))    {     /* An error has occured on this fd, or the socket is not      ready for reading (why were we notified then?) */     fprintf (stderr, "epoll error/n");     close (events[i].data.fd);     continue;    }    else if (sfd == events[i].data.fd)    {     /* We have a notification on the listening socket, which      means one or more incoming connections. */     while (1)     {      struct sockaddr in_addr;      socklen_t in_len;      int infd;      char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];      in_len = sizeof in_addr;      infd = accept (sfd, &in_addr, &in_len);      if (infd == -1)      {       if ((errno == EAGAIN) ||        (errno == EWOULDBLOCK))       {        /* We have processed all incoming         connections. */        break;       }       else       {        perror ("accept");        break;       }      }          //將地址轉化為主機名或者服務名      s = getnameinfo (&in_addr, in_len,          hbuf, sizeof hbuf,          sbuf, sizeof sbuf,          NI_NUMERICHOST | NI_NUMERICSERV);//flag參數:以數字名返回          //主機地址和服務地址      if (s == 0)      {       printf("Accepted connection on descriptor %d "         "(host=%s, port=%s)/n", infd, hbuf, sbuf);      }      /* Make the incoming socket non-blocking and add it to the       list of fds to monitor. */      s = make_socket_non_blocking (infd);      if (s == -1)      abort ();      event.data.fd = infd;      event.events = EPOLLIN | EPOLLET;      s = epoll_ctl (efd, EPOLL_CTL_ADD, infd, &event);      if (s == -1)      {       perror ("epoll_ctl");       abort ();      }     }     continue;    }    else    {     /* We have data on the fd waiting to be read. Read and      display it. We must read whatever data is available      completely, as we are running in edge-triggered mode      and won't get a notification again for the same      data. */     int done = 0;     while (1)     {      ssize_t count;      char buf[512];      count = read (events[i].data.fd, buf, sizeof(buf));      if (count == -1)      {       /* If errno == EAGAIN, that means we have read all        data. So go back to the main loop. */       if (errno != EAGAIN)       {        perror ("read");        done = 1;       }       break;      }      else if (count == 0)      {       /* End of file. The remote has closed the        connection. */       done = 1;       break;      }      /* Write the buffer to standard output */      s = write (1, buf, count);      if (s == -1)      {       perror ("write");       abort ();      }     }     if (done)     {      printf ("Closed connection on descriptor %d/n",        events[i].data.fd);      /* Closing the descriptor will make epoll remove it       from the set of descriptors which are monitored. */      close (events[i].data.fd);     }    }   }  }  free (events);  close (sfd);  return EXIT_SUCCESS; }