├── README.md
├── epoll_client.cpp
├── epoll_server.cpp
└── utility.h


/README.md:
--------------------------------------------------------------------------------
1 | # epoll
2 | 
3 | 相比非阻塞忙轮询这类无差别轮训，linux内核提供了epoll这样更高级的形式
4 | 把需要处理的IO事件添加到epoll内核列表，epoll_wait来监控并提醒用户程序当IO事件发生时
5 | 
6 | 
7 | 此聊天室客户端代码fork两个进程，子进程把用户输入写入到pipe,父进程读pipe发给服务端同时监控服务端的消息并广播
8 | 


--------------------------------------------------------------------------------
/epoll_client.cpp:
--------------------------------------------------------------------------------
https://raw.githubusercontent.com/jwzh222/epoll/f139a3927a86c84d225c1ae0e9aed240d97d5185/epoll_client.cpp


--------------------------------------------------------------------------------
/epoll_server.cpp:
--------------------------------------------------------------------------------
https://raw.githubusercontent.com/jwzh222/epoll/f139a3927a86c84d225c1ae0e9aed240d97d5185/epoll_server.cpp


--------------------------------------------------------------------------------
/utility.h:
--------------------------------------------------------------------------------
  1 | #ifndef UTILITY_H_INCLUDED
  2 | #define UTILITY_H_INCLUDED
  3 | 
  4 | #include <iostream>
  5 | #include <list>
  6 | #include <sys/types.h>
  7 | #include <sys/socket.h>
  8 | #include <netinet/in.h>
  9 | #include <arpa/inet.h>
 10 | #include <sys/epoll.h>
 11 | #include <fcntl.h>
 12 | #include <errno.h>
 13 | #include <unistd.h>
 14 | #include <stdio.h>
 15 | #include <stdlib.h>
 16 | #include <string.h>
 17 | 
 18 | using namespace std;
 19 | 
 20 | // clients_list save all the clients's socket
 21 | list<int> clients_list;
 22 | 
 23 | /**********************   macro defintion **************************/
 24 | // server ip
 25 | #define SERVER_IP "127.0.0.1"
 26 | 
 27 | // server port
 28 | #define SERVER_PORT 8888
 29 | 
 30 | //epoll size
 31 | #define EPOLL_SIZE 5000
 32 | 
 33 | //message buffer size
 34 | #define BUF_SIZE 0xFFFF
 35 | 
 36 | #define SERVER_WELCOME "Welcome you join  to the chat room! Your chat ID is: Client #%d"
 37 | 
 38 | #define SERVER_MESSAGE "ClientID %d say >> %s"
 39 | 
 40 | // exit
 41 | #define EXIT "EXIT"
 42 | 
 43 | #define CAUTION "There is only one int the char room!"
 44 | 
 45 | /**********************   some function **************************/
 46 | /**
 47 |   * @param sockfd: socket descriptor
 48 |   * @return 0
 49 | **/
 50 | int setnonblocking(int sockfd)
 51 | {
 52 |     fcntl(sockfd, F_SETFL, fcntl(sockfd, F_GETFD, 0)| O_NONBLOCK);
 53 |     return 0;
 54 | }
 55 | 
 56 | /**
 57 |   * @param epollfd: epoll handle
 58 |   * @param fd: socket descriptor
 59 |   * @param enable_et : enable_et = true, epoll use ET; otherwise LT
 60 | **/
 61 | void addfd( int epollfd, int fd, bool enable_et )
 62 | {
 63 |     struct epoll_event ev;
 64 |     ev.data.fd = fd;
 65 |     ev.events = EPOLLIN;
 66 |     if( enable_et )
 67 |         ev.events = EPOLLIN | EPOLLET;
 68 |     epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
 69 |     setnonblocking(fd);
 70 |     printf("fd added to epoll!\n\n");
 71 | }
 72 | 
 73 | /**
 74 |   * @param clientfd: socket descriptor
 75 |   * @return : len
 76 | **/
 77 | int sendBroadcastmessage(int clientfd)
 78 | {
 79 |     // buf[BUF_SIZE] receive new chat message
 80 |     // message[BUF_SIZE] save format message
 81 |     char buf[BUF_SIZE], message[BUF_SIZE];
 82 |     bzero(buf, BUF_SIZE);
 83 |     bzero(message, BUF_SIZE);
 84 | 
 85 |     // receive message
 86 |     printf("read from client(clientID = %d)\n", clientfd);
 87 |     int len = recv(clientfd, buf, BUF_SIZE, 0);
 88 | 
 89 |     if(len <= 0)  // len = 0 means the client closed connection
 90 |     {
 91 |         close(clientfd);
 92 |         clients_list.remove(clientfd); //server remove the client
 93 |         printf("ClientID = %d closed.\n now there are %d client in the char room\n", clientfd, (int)clients_list.size());
 94 | 
 95 |     }
 96 |     else  //broadcast message
 97 |     {
 98 |         if(clients_list.size() == 1) { // this means There is only one int the char room
 99 |             send(clientfd, CAUTION, strlen(CAUTION), 0);
100 |             return len;
101 |         }
102 |         // format message to broadcast
103 |         sprintf(message, SERVER_MESSAGE, clientfd, buf);
104 | 
105 |         list<int>::iterator it;
106 |         for(it = clients_list.begin(); it != clients_list.end(); ++it) {
107 |            if(*it != clientfd){
108 |                 if( send(*it, message, BUF_SIZE, 0) < 0 ) { perror("error"); exit(-1);}
109 |            }
110 |         }
111 |     }
112 |     return len;
113 | }
114 | #endif // UTILITY_H_INCLUDED
115 | 


--------------------------------------------------------------------------------