linux epoll 简单demo
一个简单的epoll demo ,同时接受多个客户端连接,并把接收到的字符串转化为大写字母返回给客户端
1 #include<stdio.h>
2 #include<arpa/inet.h>
3 #include<sys/epoll.h>
4 #include<unistd.h>
5 #include<ctype.h>
6 #define MAXLEN 1024
7 #define SERV_PORT 8000
8 #define MAX_OPEN_FD 1024
9
10 int main(int argc,char *argv[])
11 {
12 int listenfd,connfd,efd,ret;
13 char buf[MAXLEN];
14 struct sockaddr_in cliaddr,servaddr;
15 socklen_t clilen = sizeof(cliaddr);
16 struct epoll_event tep,ep[MAX_OPEN_FD];
17
18 listenfd = socket(AF_INET,SOCK_STREAM,0);
19
20 servaddr.sin_family = AF_INET;
21 servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
22 servaddr.sin_port = htons(SERV_PORT);
23 bind(listenfd,(struct sockaddr*)&servaddr,sizeof(servaddr));
24 listen(listenfd,20);
25 // 创建一个epoll fd
26 efd = epoll_create(MAX_OPEN_FD);
27 tep.events = EPOLLIN;tep.data.fd = listenfd;
28 // 把监听socket 先添加到efd中
29 ret = epoll_ctl(efd,EPOLL_CTL_ADD,listenfd,&tep);
30 // 循环等待
31 for (;;)
32 {
33 // 返回已就绪的epoll_event,-1表示阻塞,没有就绪的epoll_event,将一直等待
34 size_t nready = epoll_wait(efd,ep,MAX_OPEN_FD,-1);
35 for (int i = 0; i < nready; ++i)
36 {
37 // 如果是新的连接,需要把新的socket添加到efd中
38 if (ep[i].data.fd == listenfd )
39 {
40 connfd = accept(listenfd,(struct sockaddr*)&cliaddr,&clilen);
41 tep.events = EPOLLIN;
42 tep.data.fd = connfd;
43 ret = epoll_ctl(efd,EPOLL_CTL_ADD,connfd,&tep);
44 }
45 // 否则,读取数据
46 else
47 {
48 connfd = ep[i].data.fd;
49 int bytes = read(connfd,buf,MAXLEN);
50 // 客户端关闭连接
51 if (bytes == 0){
52 ret =epoll_ctl(efd,EPOLL_CTL_DEL,connfd,NULL);
53 close(connfd);
54 printf("client[%d] closed\n", i);
55 }
56 else
57 {
58 for (int j = 0; j < bytes; ++j)
59 {
60 buf[j] = toupper(buf[j]);
61 }
62 // 向客户端发送数据
63 write(connfd,buf,bytes);
64 }
65 }
66 }
67 }
68 return 0;
69 }
