===================================================================
RCS file: /cvs/mandoc/mandoc_html.3,v
retrieving revision 1.6
retrieving revision 1.7
diff -u -p -r1.6 -r1.7
--- mandoc/mandoc_html.3	2017/03/13 19:01:38	1.6
+++ mandoc/mandoc_html.3	2017/03/15 11:29:53	1.7
@@ -1,4 +1,4 @@
-.\"	$Id: mandoc_html.3,v 1.6 2017/03/13 19:01:38 schwarze Exp $
+.\"	$Id: mandoc_html.3,v 1.7 2017/03/15 11:29:53 schwarze Exp $
 .\"
 .\" Copyright (c) 2014, 2017 Ingo Schwarze <schwarze@openbsd.org>
 .\"
@@ -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: March 13 2017 $
+.Dd $Mdocdate: March 15 2017 $
 .Dt MANDOC_HTML 3
 .Os
 .Sh NAME
@@ -48,6 +48,14 @@
 .Fa "struct html *h"
 .Fa "const char *word"
 .Fc
+.Ft char *
+.Fo html_make_id
+.Fa "const struct roff_node *n"
+.Fc
+.Ft int
+.Fo html_strlen
+.Fa "const char *cp"
+.Fc
 .Sh DESCRIPTION
 The mandoc HTML formatter is not a formal library.
 However, as it is compiled into more than one program, in particular
@@ -306,8 +314,27 @@ and
 .Fn print_tagq
 functions.
 .Pp
+The function
+.Fn html_make_id
+takes a node containing one or more text children
+and returns a newly allocated string containing the concatenation
+of the child strings, with blanks replaced by underscores.
+If the node
+.Fa n
+contains any non-text child node,
+.Fn html_make_id
+returns
+.Dv NULL
+instead.
+The caller is responsible for freeing the returned string.
+.Pp
+The function
+.Fn html_strlen
+counts the number of characters in
+.Fa cp .
+It is used as a crude estimate of the width needed to display a string.
+.Pp
 The functions
-.Fn html_strlen ,
 .Fn print_eqn ,
 .Fn print_tbl ,
 and