select IO 模型探索

 WSADATA wsData;
 if(WSAStartup(MAKEWORD(2,2), &wsData))
 {
  TRACE("初始化失敗");

 }

 SOCKET serSock=socket(AF_INET, SOCK_STREAM, 0);
 if(serSock == SOCKET_ERROR)
 {

  TRACE("建立socket失敗");   
  WSACleanup();   
 }

 SOCKADDR_IN addr;
 addr.sin_family=AF_INET;
 addr.sin_port=htons(5005);
 addr.sin_addr.S_un.S_addr=inet_addr("127.0.0.1");

 if(bind(serSock, (SOCKADDR *)&addr, sizeof(addr)) == SOCKET_ERROR)
 {
  TRACE("建立socket失敗");
  WSACleanup();   
 }

 if(listen(serSock, 5) == SOCKET_ERROR)
 {
  TRACE("socket監聽失敗");   
  WSACleanup();       
 }

 SOCKET cliSock;
 SOCKADDR_IN cliAddr;

 int len = sizeof(cliAddr);
 char buf[MAXBULEN];
 g_bready =true;

 fd_set fd_read;
 FD_ZERO(&fd_read); 

 timeval tv;
 tv.tv_sec = 2;
 tv.tv_usec = 0;
 int res;
 while(1)
 {  
  FD_SET(serSock, &fd_read);  //將監聽通訊端加入到可讀模型中
  //g_iTotalCli += 1;

//添加鏈路檢測，將斷鏈的 socket刪除掉

 

  for(int i = 0; i < g_iTotalCli; i++ )
  {
   FD_SET(g_cliSocketArr[i], &fd_read);
  }
      
     res = select(NULL, &fd_read, NULL, NULL, &tv);
  TRACE("調用了select,傳回值 %d \n", res);
  if(res = 0)
  {
   continue;  //逾時繼續
  }
       
  if(FD_ISSET(serSock, &fd_read))
  {
   TRACE("有新的串連到來! \n");
   cliSock = accept(serSock, (SOCKADDR *)&cliAddr, &len);
   g_cliSocketArr[g_iTotalCli++] = cliSock; //接受串連 
  }

        for(int i = 0; i< g_iTotalCli; i++)
  {
   if(FD_ISSET(g_cliSocketArr[i], &fd_read))
   {
    memset(buf, 0, MAXBULEN);
    int recvRes = recv(g_cliSocketArr[i], buf, MAXBULEN, 0 );
    if(recvRes == 0 ||(res == SOCKET_ERROR && WSAGetLastError() == WSAECONNRESET))
    {
     TRACE("socket closed !\n");
     closesocket(g_cliSocketArr[i]);
     if (i < g_iTotalCli - 1)   
     {  
      g_cliSocketArr[i--] = g_cliSocketArr[--g_iTotalCli];  
     } 
    }
    else
    {
     buf[recvRes] = '\0';
     TRACE("接受到的訊息: %s\n", buf);
    }
   }
  }
 }
 return 0;