lter.html#synopsis"><CODE>output_filter</CODE></A> help users define new Filter types; the template <A href="../classes/filter.html#multichar_filter"><CODE>multichar_filter</CODE></A> and its specializations <A HREF="../classes/filter.html#synopsis"><CODE>multichar_input_filter</CODE></A> and <A HREF="../classes/filter.html#synopsis"><CODE>multichar_output_filter</CODE></A> help users define new multichar Filter types. There are also wide-character versions of these templates, <A href="../classes/device.htm