#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();

 }