@Section
   @Title { "@SetUnderlineColour" and "@SetUnderlineColor" }
   @Tag { underline_colour }
@Begin
@PP
The @@SetUnderlineColour and @@SetUnderlineColor symbols,
setunderlinecolour.sym @Index { @@SetUnderlineColour symbol }
setunderlinecolor.sym @Index { @@SetUnderlineColor symbol }
which have identical effect, ensure that any underlining in
the right parameter is done in the colour specified by their
left parameter.  The left parameter is a colour as for
@@SetColour in Section {@NumberOf colour}.
@PP
To actually get underlining, you have to use the @@Underline
symbol (Section {@NumberOf underline}).
@PP
Note that the @@SetColour symbol from Section {@NumberOf colour}
includes the effect of @@SetUnderlineColour, so in the usual
case where underlining is to be in the same colour as the text
being underlined, there is no need to use @@SetUnderlineColour.
@End @Section