socket学习笔记——select与epoll函数的使用（linux)

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include <unistd.h>
 5 #include <arpa/inet.h>
 6 #include <sys/socket.h>
 7 #include <sys/time.h>
 8 #include <sys/socket.h>
 9 
10 #define BUF_SIZE 100
11 void error_handling(char* message);
12 
13 int main(int argc,char* argv[])
14 {
15     int serv_sock,clnt_sock;
16     struct sockaddr_in serv_addr,clnt_addr;
17     struct timeval timeout;
18     fd_set reads,cp_reads;
19     socklen_t adr_sz;
20     int fd_max,str_len,fd_num,i;
21     char buf[BUF_SIZE];
22 
23     if(argc != 2)
24     {
25         printf("usage: %s <port>\n",argv[0]);
26         exit(1);
27     }
28 
29     serv_sock = socket(PF_INET,SOCK_STREAM,0);
30     memset(&serv_addr,0,sizeof(serv_addr));
31     serv_addr.sin_family = AF_INET;
32     serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
33     serv_addr.sin_port = htons(atoi(argv[1]));
34 
35     if(bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr)) == -1)
36         error_handling("bind error");
37     if(listen(serv_sock,5) == -1)
38         error_handling("listen error");
39   
40     FD_ZERO(&reads);
41     FD_SET(serv_sock,&reads);
42     fd_max = serv_sock;
43     while(1)
44     {
45         cp_reads = reads;
46         timeout.tv_sec = 5;
47 
48         if((fd_num = select(fd_max+1,&cp_reads,0,0,&timeout)) == -1)
49             break;
50         if(fd_num == 0)
51             continue;
52 
53         for(i = 0;i < fd_max+1;i++)
54         {
55             if(FD_ISSET(i,&cp_reads))
56             {
57                 if(i == serv_sock)
58                 {
59                     adr_sz = sizeof(clnt_addr);
60                     clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_addr,&adr_sz);
61                     FD_SET(clnt_sock,&reads);
62                     if(fd_max < clnt_sock)
63                         fd_max = clnt_sock;
64                     printf("connected client:%d \n",clnt_sock);
65                 }
66                 else
67                 {
68                     str_len = read(i,buf,BUF_SIZE);
69                     if(str_len == 0)
70                     {
71                         FD_CLR(i,&reads);
72                         close(i);
73                         printf("closed client: %d\n",i);
74                     }
75                     else
76                         write(i,buf,str_len);
77                 }
78             }
79         }
80     }
81     close(serv_sock);
82     return 0;
83 }
84 
85 void error_handling(char* message)
86 {
87     fputs(message,stderr);
88     fputc(‘\n‘,stderr);
89     exit(1);
90 }

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include <unistd.h>
 5 #include <arpa/inet.h>
 6 #include <sys/socket.h>
 7 #include <sys/epoll.h>
 8 
 9 #define BUF_SIZE 100
10 #define EPOLL_SIZE 50
11 void error_handling(char* message);
12 int main(int argc,char* argv[])
13 {
14     struct sockaddr_in serv_addr,clnt_addr;
15     int serv_sock,clnt_sock;
16     socklen_t adr_sz;
17     int str_len,i;
18     char buf[BUF_SIZE];
19     
20     struct epoll_event *ep_events;
21     struct epoll_event event;
22     int epfd,event_cnt;
23 
24     if(argc != 2)
25     {
26         printf("usage:%s <port>\n",argv[0]);
27         exit(1);
28     }
29 
30     serv_sock = socket(PF_INET,SOCK_STREAM,0);
31     serv_addr.sin_family = AF_INET;
32     serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
33     serv_addr.sin_port = htons(atoi(argv[1]));
34 
35     if(bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr)) == -1)
36         error_handling("bind error");
37     if(listen(serv_sock,5) == -1)
38         error_handling("listen error");
39 
40     epfd = epoll_create(EPOLL_SIZE);
41     ep_events = malloc(sizeof(struct epoll_event)*EPOLL_SIZE);
42 
43     event.events = EPOLLIN;
44     event.data.fd = serv_sock;
45     epoll_ctl(epfd,EPOLL_CTL_ADD,serv_sock,&event);
46 
47     while(1)
48     {
49         event_cnt = epoll_wait(epfd,ep_events,EPOLL_SIZE,-1);
50         if(event_cnt == -1)
51         {
52             puts("epoll_wait error");
53             break;
54         }
55         for(i = 0;i < event_cnt;i++)
56         {
57             if(ep_events[i].data.fd == serv_sock)
58             {
59                 adr_sz = sizeof(clnt_addr);
60                 clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_addr,&adr_sz);
61                 event.events = EPOLLIN;
62                 event.data.fd = clnt_sock;
63                 epoll_ctl(epfd,EPOLL_CTL_ADD,clnt_sock,&event);
64                 printf("connected client:%d\n",clnt_sock);
65             }
66             else
67             {
68                 str_len = read(ep_events[i].data.fd,buf,BUF_SIZE);
69                 if(str_len == 0)
70                 {
71                     epoll_ctl(epfd,EPOLL_CTL_DEL,ep_events[i].data.fd,NULL);
72                     close(ep_events[i].data.fd);
73                     printf("closed client:%d\n",ep_events[i].data.fd);
74                 }
75                 else
76                     write(ep_events[i].data.fd,buf,str_len);
77             }
78         }
79     }
80     close(serv_sock);
81     close(epfd);
82     return 0;
83 }
84 
85 void error_handling(char* message)
86 {
87     fputs(message,stderr);
88     fputc(‘\n‘,stderr);
89     exit(1);
90 }