代码示例_网络编程_select

select_多路复用

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1.头文件

 1 #pragma once
 2 
 3 #include <stdio.h>
 4 #include <stdlib.h>
 5 #include <sys/types.h>
 6 #include <sys/select.h>
 7 #include <sys/time.h>
 8 #include <sys/socket.h>
 9 #include <strings.h>
10 #include <string.h>
11 #include <arpa/inet.h>
12 
13 #define IP "192.168.2.150"
14 #define PORT 9999
15 #define SIZE 128

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2.client_select

 1 #include "net.h"
 2 
 3 int main(void)
 4 {
 5     //1.创建套接字
 6     int fd = socket(AF_INET,SOCK_STREAM,0);
 7     if(fd<0){
 8         perror("socket failed");
 9         exit(1);
10     }
11 
12 
13     //2.初始服务器地址
14     struct sockaddr_in cli;
15     cli.sin_family = AF_INET;
16     cli.sin_port = htons(PORT);
17     cli.sin_addr.s_addr=inet_addr(IP);
18 
19 
20     //3.发起连接请求
21     if(  connect(fd,(struct sockaddr*)&cli,sizeof(cli))<0  ){
22         perror("connect failed");
23         exit(1);
24     }
25 
26 
27     //4.写
28     char buf[SIZE];
29     while(1){
30     bzero(buf,SIZE);
31     printf("please input:\t");
32     fgets(buf,SIZE,stdin);
33     write(fd,buf,strlen(buf));
34         if(!strncmp(buf,"quit",4))
35         break;
36     }
37 
38 
39     //5.关闭
40     close(fd);
41 
42 
43     return 0 ;
44 }

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3.server_select

  1 #include "net.h"
  2 
  3 int main(void)
  4 {
  5     char buf[SIZE];
  6     int  newfd = -1;
  7 
  8     //1.创建套接字
  9     int fd = socket(AF_INET,SOCK_STREAM,0);
 10     if(fd<0){
 11         perror("socket failed");
 12         exit(1);
 13     }
 14 
 15 
 16     //2.初始本地地址
 17     struct sockaddr_in ser;
 18     ser.sin_family = AF_INET;
 19     ser.sin_port = htons(PORT);
 20     ser.sin_addr.s_addr=htonl(INADDR_ANY);
 21 
 22 
 23     //3.绑定
 24     if(  bind(fd,(struct sockaddr*)&ser,sizeof(ser))<0  ){
 25         perror("bind failed");
 26         exit(1);
 27     }
 28 
 29     //4.监听
 30     if(  listen(fd,5)<0  ){
 31         perror("listen failed");
 32         exit(1);
 33     }
 34 
 35     int len = sizeof(ser);
 36     
 37     
 38     //5.多路复用
 39     fd_set read_fds;    //定义读集合
 40     FD_ZERO(&read_fds); //清空读集合
 41     int maxfd = fd;        //最大描述符
 42 
 43 
 44     //6.加入监听处理 读集合
 45     while(1){
 46     FD_SET(0,&read_fds);  //将标准输入加入读集合
 47     FD_SET(fd,&read_fds); //将fd加入读集合
 48     maxfd = fd;           //表示最大读集合
 49     if(maxfd < newfd){
 50         FD_SET(newfd,&read_fds);
 51         maxfd = newfd;
 52     }
 53 
 54     int ret = select(maxfd+1,&read_fds,NULL,NULL,NULL);
 55     if(ret<0){
 56         perror("select failed");
 57         exit(1);
 58     }
 59     else if(ret==0){
 60         perror("time out");
 61         break;
 62     }
 63     else{
 64         //6.1 判断输入端是否有相应
 65         if(FD_ISSET(0,&read_fds)){
 66             bzero(buf,SIZE);
 67             fgets(buf,SIZE,stdin);
 68             printf("shell :%s",buf);
 69         }
 70         //6.2判断客户端是否有相应
 71         if(FD_ISSET(fd,&read_fds)){
 72             //接收
 73             newfd=accept(fd,(struct sockaddr*)&ser,&len);
 74             if(newfd<0){
 75                 perror("accept failed");
 76                 exit(1);
 77             }
 78             printf("client connect succsee :  ip=%s   port=%d  用户上线啦 ^.^ ...\n",inet_ntoa(ser.sin_addr),ntohs(ser.sin_port));
 79         }
 80         //6.3判断客户端是否有数据
 81         if(FD_ISSET(newfd,&read_fds)){
 82             bzero(buf,SIZE);    // 读之前清理一下，要不然内存可能有残余保留！！
 83             int val=read(newfd,buf,SIZE);
 84             if(val<0){
 85                 perror("read failed");
 86                 exit(1);
 87             }
 88             else if(val==0){
 89                 FD_CLR(newfd,&read_fds);
 90                 close(newfd);
 91                 newfd=-1;
 92             }
 93             else{
 94                 printf("client info :\nip=%s  port=%d\ndata=%s\n",inet_ntoa(ser.sin_addr),ntohs(ser.sin_port),buf);
 95                 if(!strncmp(buf,"quit",4))
 96                     printf("client info :\nip=%s  port=%d  用户下线啦 ^.^ ...\n",inet_ntoa(ser.sin_addr),ntohs(ser.sin_port));
 97             }
 98         }    
 99     }
100     }
101 
102     
103     return 0 ;
104 }

 测试：

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 success  ！