socket超时设置

//连接超时
    //--------------------------------------------------------------------------
    //设置为非阻塞方式连接
    unsigned long ul = 1;
    int ret = ioctlsocket(m_sSocket, FIONBIO, (unsigned long*)&ul);
    if(ret == SOCKET_ERROR)
    {
        err = WSAGetLastError();
  closesocket(m_sSocket);
  m_sSocket = NULL;
  return FALSE;
    }

 struct         timeval timeout ;  // 超时结构
    fd_set         r;                     

    FD_ZERO(&r);
    FD_SET(m_sSocket, &r);
    timeout.tv_sec = iTimeout;   // 连接超时设置
    timeout.tv_usec =0;

    connect(m_sSocket,(LPSOCKADDR)&server,sizeof(SOCKADDR));
    ret = select(0, 0, &r, 0, &timeout); 
    if ( ret <= 0 )
    {
  err = WSAGetLastError();
  closesocket(m_sSocket);
  m_sSocket = NULL;
  return FALSE;
    }

 //设回阻塞模式
    ul = 0 ;
    ret = ioctlsocket(m_sSocket, FIONBIO, (unsigned long*)&ul);
    //--------------------------------------------------------------------------

//接收超时
    //-------------------------------------------
    //接收超时设置
    struct         timeval outtime ;  // 超时结构

    FD_SET fdr = {1, m_sSocket};
    outtime.tv_sec = timeout;  
    outtime.tv_usec =0;
    int nSelectRet;
    //------------------------------------------------------------
    //网络只认单字节串，而EVC里多字节;发送的UNICODE串转换成单字节串
    UINT nLen = len * 2;
    char *pByte = new char[nLen+1];
    memset(pByte, 0, nLen+1);
    WideCharToMultiByte(CP_ACP, NULL, buf, wcslen(buf),pByte, nLen, NULL, NULL);
    int nRet;

    nSelectRet=::select(0, &fdr, NULL, NULL, &outtime); //检查可读状态
    if(SOCKET_ERROR==nSelectRet)
    {
 err = WSAGetLastError();
 closesocket(m_sSocket);
 m_sSocket = NULL;
 return -1;
    }
    if(nSelectRet==0) //超时发生，无可读数据
    {
 AfxMessageBox(L"接收超时");
 err = WSAGetLastError();
 closesocket(m_sSocket);
 m_sSocket = NULL;
 return -1;
    }
    else
    {
 //接收数据
 nRet = recv(m_sSocket, pByte, nLen, 0);
 if(nRet == SOCKET_ERROR)
 {
  err = WSAGetLastError();
 }
    }

    //-------------------------------------------

    MultiByteToWideChar(CP_ACP, NULL, pByte, nLen, buf, len);
    delete [] pByte;
    pByte = NULL;
 
    //---------------------------------------------------------------------