-.\" $Id: mandoc.1,v 1.258 2022/04/28 16:21:09 schwarze Exp $
+.\" $Id: mandoc.1,v 1.262 2022/07/03 14:36:00 schwarze Exp $
.\"
.\" Copyright (c) 2012, 2014-2022 Ingo Schwarze <schwarze@openbsd.org>
.\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
-.Dd $Mdocdate: April 28 2022 $
+.Dd $Mdocdate: July 3 2022 $
.Dt MANDOC 1
.Os
.Sh NAME
Output produced by
.Fl T Cm html
conforms to HTML5 using optional self-closing tags.
-Default styles use only CSS1.
Equations rendered from
.Xr eqn 7
blocks use MathML.
.Pq mdoc
A new sentence starts in the middle of a text line.
Start it on a new input line to help formatters produce correct spacing.
-.It Sy "invalid escape sequence"
+.It Sy "invalid escape sequence argument"
.Pq roff
-An escape sequence has an invalid opening argument delimiter, lacks the
-closing argument delimiter, the argument is of an invalid form, or it is
-a character escape sequence with an invalid name.
-If the argument is incomplete,
-.Ic \e*
-and
-.Ic \en
-expand to an empty string,
-.Ic \eB
-to the digit
-.Sq 0 ,
-and
-.Ic \ew
-to the length of the incomplete argument.
-All other invalid escape sequences are ignored.
+The argument of an escape sequence is of an invalid form.
+Invalid escape sequences are ignored.
.It Sy "undefined escape, printing literally"
.Pq roff
In an escape sequence, the first character
.El
The excess arguments are ignored.
.El
+.Ss "Errors related to escape sequences"
+.Bl -ohang
+.It Sy "incomplete escape sequence"
+.Pq roff
+The end of the input line is encountered
+while parsing the argument of an escape sequence.
+In this case,
+.Ic \e*
+and
+.Ic \en
+expand to an empty string,
+.Ic \eB
+to the digit
+.Sq 0 ,
+and
+.Ic \ew
+to the length of the incomplete argument.
+All other incomplete escape sequences are ignored.
+.It Sy "invalid special character"
+.Pq roff
+A special character escape sequence is invalid,
+for example a Unicode sequence pointing to a surrogate
+or beyond the Unicode range, a \e[char...] escape sequence
+representing a control character or pointing beyond the
+.Vt unsigned char
+range, or an invalid variable-length form
+of a single-byte character escape sequence, for example writing
+.Qq \e[e]
+or
+.Qq \e[~]
+instead of
+.Qq \ee
+or
+.Qq \e~ ,
+respectively.
+The escape sequence is ignored.
+.It Sy "unknown special character"
+.Pq roff
+The name given in a special character escape sequence is not known to
+.Nm .
+The escape sequence is ignored.
+.It Sy "invalid escape argument delimiter"
+.Pq roff
+An escape sequence that expects a numerical argument
+attempts to employ one of the characters
+.Qq " %&()*+-./0123456789:<=>"
+as an argument delimiter.
+The escape sequence is ignored including the invalid opening delimiter
+and the rest of the argument may appear as output text.
+While various characters can be used as argument delimiters,
+using the apostrophe-quote character
+.Pq Sq \(aq
+is recommended for readability and robustness.
+.El
.Ss Unsupported features
.Bl -ohang
.It Sy "input too large"