socket学习笔记——select函数的使用（windows)

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include <winsock2.h>
 5 
 6 #define BUF_SIZE 1024
 7 void error_handling(char* message);
 8 
 9 int main(int argc, char* argv[])
10 {
11     WSADATA wsadata;
12     SOCKET hServSock, hClntSock;
13     SOCKADDR_IN servAddr, clntAddr;
14     TIMEVAL timeout;
15     fd_set reads, cp_reads;
16 
17     int adr_sz;
18     int str_len, i,fd_num;
19     char buf[BUF_SIZE];
20 
21     if (argc != 2)
22     {
23         printf("usage:%s <port>
",argv[0]);
24         exit(1);
25     }
26     if (WSAStartup(MAKEWORD(2, 2), &wsadata) != 0)
27         error_handling("WSAStartup error");
28 
29     hServSock = socket(PF_INET, SOCK_STREAM, 0);
30     memset(&servAddr, 0, sizeof(servAddr));
31     servAddr.sin_family = AF_INET;
32     servAddr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
33     servAddr.sin_port = htons(atoi(argv[1]));
34 
35     if (bind(hServSock, (SOCKADDR*)&servAddr, sizeof(servAddr)) == SOCKET_ERROR)
36         error_handling("bind error");
37     if (listen(hServSock, 5) == SOCKET_ERROR)
38         error_handling("listen error");
39 
40     FD_ZERO(&reads);
41     FD_SET(hServSock, &reads);
42 
43     while (1)
44     {
45         cp_reads = reads;
46         timeout.tv_sec = 5;
47 
48         if ((fd_num = select(0, &cp_reads, 0, 0, &timeout)) == SOCKET_ERROR)
49             break;
50         if (fd_num == 0)
51             continue;
52 
53         for (i = 0;i < reads.fd_count;i++)
54         {
55             if (FD_ISSET(reads.fd_array[i], &cp_reads))
56             {
57                 if (reads.fd_array[i] == hServSock)
58                 {
59                     adr_sz = sizeof(clntAddr);
60                     hClntSock = accept(hServSock, (SOCKADDR*)&servAddr, &adr_sz);
61                     FD_SET(hClntSock, &reads);
62                     printf("connected client:%d
", hClntSock);
63                 }
64                 else
65                 {
66                     str_len = recv(reads.fd_array[i], buf, BUF_SIZE - 1, 0);
67                     if (str_len == 0)
68                     {
69                         FD_CLR(reads.fd_array[i], &reads);
70                         closesocket(cp_reads.fd_array[i]);
71                         printf("closed client:%d
", cp_reads.fd_array[i]);
72                     }
73                     else
74                         send(reads.fd_array[i], buf, str_len, 0);
75                 }
76             }
77         }
78     }
79     closesocket(hServSock);
80     WSACleanup();
81     return 0;
82 }
83 
84 void error_handling(char* message)
85 {
86     fputs(message, stderr);
87     fputc('
', stderr);
88     exit(1);
89 }