socket学习笔记——select与epoll函数的使用（linux)

select.c

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <arpa/inet.h>
 #include <sys/socket.h>
 #include <sys/time.h>
 #include <sys/socket.h>

 #define BUF_SIZE 100
 void error_handling(char* message);

 int main(int argc,char* argv[])
 {
     int serv_sock,clnt_sock;
     struct sockaddr_in serv_addr,clnt_addr;
     struct timeval timeout;
     fd_set reads,cp_reads;
     socklen_t adr_sz;
     int fd_max,str_len,fd_num,i;
     char buf[BUF_SIZE];

     if(argc != )
     {
         printf("usage: %s <port>\n",argv[]);
         exit();
     }

     serv_sock = socket(PF_INET,SOCK_STREAM,);
     memset(&serv_addr,,sizeof(serv_addr));
     serv_addr.sin_family = AF_INET;
     serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
     serv_addr.sin_port = htons(atoi(argv[]));

     if(bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr)) == -)
         error_handling("bind error");
     if(listen(serv_sock,) == -)
         error_handling("listen error");

     FD_ZERO(&reads);
     FD_SET(serv_sock,&reads);
     fd_max = serv_sock;
     while()
     {
         cp_reads = reads;
         timeout.tv_sec = ;

         if((fd_num = select(fd_max+,&cp_reads,,,&timeout)) == -)
             break;
         if(fd_num == )
             continue;

         for(i = ;i < fd_max+;i++)
         {
             if(FD_ISSET(i,&cp_reads))
             {
                 if(i == serv_sock)
                 {
                     adr_sz = sizeof(clnt_addr);
                     clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_addr,&adr_sz);
                     FD_SET(clnt_sock,&reads);
                     if(fd_max < clnt_sock)
                         fd_max = clnt_sock;
                     printf("connected client:%d \n",clnt_sock);
                 }
                 else
                 {
                     str_len = read(i,buf,BUF_SIZE);
                     if(str_len == )
                     {
                         FD_CLR(i,&reads);
                         close(i);
                         printf("closed client: %d\n",i);
                     }
                     else
                         write(i,buf,str_len);
                 }
             }
         }
     }
     close(serv_sock);
     return ;
 }

 void error_handling(char* message)
 {
     fputs(message,stderr);
     fputc('\n',stderr);
     exit();
 }

epoll.c

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <arpa/inet.h>
 #include <sys/socket.h>
 #include <sys/epoll.h>

 #define BUF_SIZE 100
 #define EPOLL_SIZE 50
 void error_handling(char* message);
 int main(int argc,char* argv[])
 {
     struct sockaddr_in serv_addr,clnt_addr;
     int serv_sock,clnt_sock;
     socklen_t adr_sz;
     int str_len,i;
     char buf[BUF_SIZE];

     struct epoll_event *ep_events;
     struct epoll_event event;
     int epfd,event_cnt;

     if(argc != )
     {
         printf("usage:%s <port>\n",argv[]);
         exit();
     }

     serv_sock = socket(PF_INET,SOCK_STREAM,);
     serv_addr.sin_family = AF_INET;
     serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
     serv_addr.sin_port = htons(atoi(argv[]));

     if(bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr)) == -)
         error_handling("bind error");
     if(listen(serv_sock,) == -)
         error_handling("listen error");

     epfd = epoll_create(EPOLL_SIZE);
     ep_events = malloc(sizeof(struct epoll_event)*EPOLL_SIZE);

     event.events = EPOLLIN;
     event.data.fd = serv_sock;
     epoll_ctl(epfd,EPOLL_CTL_ADD,serv_sock,&event);

     while()
     {
         event_cnt = epoll_wait(epfd,ep_events,EPOLL_SIZE,-);
         if(event_cnt == -)
         {
             puts("epoll_wait error");
             break;
         }
         for(i = ;i < event_cnt;i++)
         {
             if(ep_events[i].data.fd == serv_sock)
             {
                 adr_sz = sizeof(clnt_addr);
                 clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_addr,&adr_sz);
                 event.events = EPOLLIN;
                 event.data.fd = clnt_sock;
                 epoll_ctl(epfd,EPOLL_CTL_ADD,clnt_sock,&event);
                 printf("connected client:%d\n",clnt_sock);
             }
             else
             {
                 str_len = read(ep_events[i].data.fd,buf,BUF_SIZE);
                 if(str_len == )
                 {
                     epoll_ctl(epfd,EPOLL_CTL_DEL,ep_events[i].data.fd,NULL);
                     close(ep_events[i].data.fd);
                     printf("closed client:%d\n",ep_events[i].data.fd);
                 }
                 else
                     write(ep_events[i].data.fd,buf,str_len);
             }
         }
     }
     close(serv_sock);
     close(epfd);
     return ;
 }

 void error_handling(char* message)
 {
     fputs(message,stderr);
     fputc('\n',stderr);
     exit();
 }