网上找到的一个函数，侦查判断服务器与客户端通信中断，看的不怎么明白，请大家不吝赐教

BOOL CClientSocket::HasConnectionDropped( void )
{
    BOOL bConnDropped = FALSE;
    INT iRet = 0;
    BOOL bOK = TRUE;
    
    struct timeval timeout = { 0, 0 };
    fd_set readSocketSet;
    
    FD_ZERO( &readSocketSet );
    FD_SET( m_hSocket, &readSocketSet );
    
    iRet = ::select( 0, &readSocketSet, NULL, NULL, &timeout );
    bOK = (iRet > 0);
    
    if(bOK)
    {
        bOK = FD_ISSET( m_hSocket, &readSocketSet );
    }
    
    if( bOK )
    {
        CHAR szBuffer[1] = "";
        iRet = ::recv( m_hSocket, szBuffer, 1, MSG_PEEK );
        bOK = ( iRet > 0 );
        if( !bOK )
        {
            INT iError = ::WSAGetLastError();
            bConnDropped = ( ( iError == WSAENETRESET ) ||
                           (iError == WSAECONNABORTED ) ||
                           (  iError == WSAECONNRESET ) ||
                           (      iError == WSAEINVAL ) ||
                           ( iRet == 0 ) ); //Graceful disconnect from other side.
        }
    }
    return( bConnDropped );
}