select Demo

 #include <iostream>
 #include <WinSock2.h>

 using namespace std;

 #pragma comment(lib, "ws2_32")

 int main(int argc, char **argv)
 {
     WSADATA wsaData;
     WSAStartup(WINSOCK_VERSION, &wsaData);

     USHORT uPort = ;
     SOCKET sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     if (INVALID_SOCKET == sListen)
     {
         cout << "socket error : " << GetLastError() << endl;
         return ;
     }

     SOCKADDR_IN sin;
     sin.sin_family = AF_INET;
     sin.sin_port = htons(uPort);
     sin.sin_addr.S_un.S_addr = INADDR_ANY;

     if (SOCKET_ERROR == bind(sListen, (PSOCKADDR)&sin, sizeof(sin)))
     {
         cout << "Bind error : " << WSAGetLastError() << endl;
         closesocket(sListen);
         WSACleanup();
         return ;
     }

     if (SOCKET_ERROR == listen(sListen, ))
     {
         cout << "listen error : " << WSAGetLastError() << endl;
         closesocket(sListen);
         WSACleanup();
         return ;
     }

     fd_set fdSocket;
     FD_ZERO(&fdSocket);
     FD_SET(sListen, &fdSocket);

     while (TRUE)
     {
         fd_set fdRead = fdSocket;
         int iRet = select(, &fdRead, NULL, NULL, NULL);
         if (iRet > )
         {
             for (size_t i = ; i < fdSocket.fd_count; i++)
             {
                 if (FD_ISSET(fdSocket.fd_array[i], &fdRead))
                 {
                     if (fdSocket.fd_array[i] == sListen)
                     {
                         if (fdSocket.fd_count < FD_SETSIZE)
                         {
                             SOCKADDR_IN addrRemote;
                             int iAddrLen = sizeof(addrRemote);
                             SOCKET sNew = accept(sListen, (PSOCKADDR)&addrRemote, &iAddrLen);
                             FD_SET(sNew, &fdSocket);
                             cout << "接收到连接（" << inet_ntoa(addrRemote.sin_addr) << "）" << endl;
                         }
                         else
                         {
                             cout << "连接太多!" << endl;
                             continue;
                         }
                     }
                     else
                     {
                         char szText[];
                         int iRecv = recv(fdSocket.fd_array[i], szText, strlen(szText), );
                         if (iRecv > )
                         {
                             szText[iRecv] = '\0';
                             cout << "接收到数据：" << szText << endl;
                         }
                         else
                         {
                             closesocket(fdSocket.fd_array[i]);
                             FD_CLR(fdSocket.fd_array[i], &fdSocket);
                         }
                     }
                 }
             }
         }
         else
         {
             cout << "select error : " << WSAGetLastError() << endl;
             closesocket(sListen);
             WSACleanup();
             break;
         }
     }

     shutdown(sListen, SD_RECEIVE);
     WSACleanup();

     return ;
 }