socket学习笔记——select函数的使用（windows)

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <winsock2.h>

 #define BUF_SIZE 1024
 void error_handling(char* message);

 int main(int argc, char* argv[])
 {
     WSADATA wsadata;
     SOCKET hServSock, hClntSock;
     SOCKADDR_IN servAddr, clntAddr;
     TIMEVAL timeout;
     fd_set reads, cp_reads;

     int adr_sz;
     int str_len, i,fd_num;
     char buf[BUF_SIZE];

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

     hServSock = socket(PF_INET, SOCK_STREAM, );
     memset(&servAddr, , sizeof(servAddr));
     servAddr.sin_family = AF_INET;
     servAddr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
     servAddr.sin_port = htons(atoi(argv[]));

     if (bind(hServSock, (SOCKADDR*)&servAddr, sizeof(servAddr)) == SOCKET_ERROR)
         error_handling("bind error");
     if (listen(hServSock, ) == SOCKET_ERROR)
         error_handling("listen error");

     FD_ZERO(&reads);
     FD_SET(hServSock, &reads);

     while ()
     {
         cp_reads = reads;
         timeout.tv_sec = ;

         if ((fd_num = select(, &cp_reads, , , &timeout)) == SOCKET_ERROR)
             break;
         if (fd_num == )
             continue;

         for (i = ;i < reads.fd_count;i++)
         {
             if (FD_ISSET(reads.fd_array[i], &cp_reads))
             {
                 if (reads.fd_array[i] == hServSock)
                 {
                     adr_sz = sizeof(clntAddr);
                     hClntSock = accept(hServSock, (SOCKADDR*)&servAddr, &adr_sz);
                     FD_SET(hClntSock, &reads);
                     printf("connected client:%d\n", hClntSock);
                 }
                 else
                 {
                     str_len = recv(reads.fd_array[i], buf, BUF_SIZE - , );
                     if (str_len == )
                     {
                         FD_CLR(reads.fd_array[i], &reads);
                         closesocket(cp_reads.fd_array[i]);
                         printf("closed client:%d\n", cp_reads.fd_array[i]);
                     }
                     else
                         send(reads.fd_array[i], buf, str_len, );
                 }
             }
         }
     }
     closesocket(hServSock);
     WSACleanup();
     return ;
 }

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