wo separate sequences, <CODE>close</CODE> delegates to a member function <CODE>close</CODE> taking <CODE>openmode</CODE> and stream buffer parameters.
    <LI CLASS="square">Otherwise, <CODE>close</CODE> delegates to a member function <CODE>close</CODE> taking a single stream buffer parameter, but only if its <CODE>openmode</CODE> parameter is consistent with the mode of <CODE>T</CODE>. 
</UL>

<P>The last condition prevents a Filter controlling a single sequence from being closed twice in succession.</P>

