===================================================================
RCS file: /cvs/mandoc/mandoc_html.3,v
retrieving revision 1.2
retrieving revision 1.6
diff -u -p -r1.2 -r1.6
--- mandoc/mandoc_html.3	2017/01/17 01:47:51	1.2
+++ mandoc/mandoc_html.3	2017/03/13 19:01:38	1.6
@@ -1,6 +1,6 @@
-.\"	$Id: mandoc_html.3,v 1.2 2017/01/17 01:47:51 schwarze Exp $
+.\"	$Id: mandoc_html.3,v 1.6 2017/03/13 19:01:38 schwarze Exp $
 .\"
-.\" Copyright (c) 2014 Ingo Schwarze <schwarze@openbsd.org>
+.\" Copyright (c) 2014, 2017 Ingo Schwarze <schwarze@openbsd.org>
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: January 17 2017 $
+.Dd $Mdocdate: March 13 2017 $
 .Dt MANDOC_HTML 3
 .Os
 .Sh NAME
@@ -137,15 +137,43 @@ Most attributes require one
 .Va char *
 argument which becomes the value of the attribute.
 The arguments have to be given in the same order as the attribute letters.
+If an argument is
+.Dv NULL ,
+the respective attribute is not written.
 .Bl -tag -width 1n -offset indent
 .It Cm c
 Print a
 .Cm class
 attribute.
+This attribute letter can optionally be followed by the modifier letter
+.Cm T .
+In that case, a
+.Cm title
+attribute with the same value is also printed.
 .It Cm h
 Print a
 .Cm href
 attribute.
+This attribute letter can optionally be followed by a modifier letter.
+If followed by
+.Cm R ,
+it formats the link as a local one by prefixing a
+.Sq #
+character.
+If followed by
+.Cm I ,
+it interpretes the argument as a header file name
+and generates a link using the
+.Xr mandoc 1
+.Fl O Cm includes
+option.
+If followed by
+.Cm M ,
+it takes two arguments instead of one, a manual page name and
+section, and formats them as a link to a manual page using the
+.Xr mandoc 1
+.Fl O Cm man
+option.
 .It Cm i
 Print an
 .Cm id
@@ -155,13 +183,15 @@ Print an arbitrary attribute.
 This format letter requires two
 .Vt char *
 arguments, the attribute name and the value.
+The name must not be
+.Dv NULL .
 .It Cm s
 Print a
 .Cm style
 attribute.
 If present, it must be the last format letter.
 In contrast to the other format letters, this one does not yet
-print the value and does not require an argument.
+print the value and does not take an argument.
 Instead, the rest of the format string consists of pairs of
 argument type letters and style name letters.
 .El
@@ -192,6 +222,13 @@ Requires one
 argument, interpreted as an
 .Xr mdoc 7 Ns -style
 width specifier.
+If the argument is
+.Dv NULL ,
+nothing is printed for this pair.
+.It Cm W
+Similar to
+.Cm w ,
+but makes the width negative by multiplying it with \(mi1.
 .El
 .Pp
 Style name letters decide what to do with the preceding argument:
@@ -231,12 +268,12 @@ requires two
 .Vt char *
 arguments.
 The first is the style name, the second its value.
+The style name must not be
+.Dv NULL .
 .El
 .Pp
 .Fn print_otag
 uses the private function
-.Fn print_attr
-which in turn uses the private function
 .Fn print_encode
 to take care of HTML encoding.
 If required by the element type, it remembers in
@@ -270,28 +307,6 @@ and
 functions.
 .Pp
 The functions
-.Fn bufinit ,
-.Fn bufcat* ,
-and
-.Fn buffmt*
-do not directly produce output but buffer text in the
-.Fa buf
-member of
-.Fa h .
-They are not used internally by
-.Pa html.c
-but intended for use by the language-specific formatters
-to ease preparation of strings for the
-.Fa p
-argument of
-.Fn print_otag
-and for the
-.Fa word
-argument of
-.Fn print_text .
-Consequently, these functions do not do any HTML encoding.
-.Pp
-The functions
 .Fn html_strlen ,
 .Fn print_eqn ,
 .Fn print_tbl ,
@@ -340,5 +355,6 @@ implementation of common mandoc utility functions
 .An -nosplit
 The mandoc HTML formatter was written by
 .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .
-This manual was written by
-.An Ingo Schwarze Aq Mt schwarze@openbsd.org .
+It is maintained by
+.An Ingo Schwarze Aq Mt schwarze@openbsd.org ,
+who also wrote this manual.