-.\" $Id: mandoc.1,v 1.256 2022/04/14 10:10:22 schwarze Exp $
+.\" $Id: mandoc.1,v 1.261 2022/06/22 17:37:59 schwarze Exp $
.\"
-.\" Copyright (c) 2012, 2014-2021 Ingo Schwarze <schwarze@openbsd.org>
+.\" Copyright (c) 2012, 2014-2022 Ingo Schwarze <schwarze@openbsd.org>
.\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" 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 14 2022 $
+.Dd $Mdocdate: June 22 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.
layout modifier has an unknown
.Ar font
argument.
+.It Sy "ignoring distance argument"
+.Pq roff
+In addition to the margin character, an
+.Ic \&mc
+request has a second argument supposed to represent a distance, but the
+.Nm
+implementation of
+.Ic \&mc
+always ignores the second argument.
.It Sy "odd number of characters in request"
.Pq roff
A
.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
.Pq roff
The argument of the escape sequence \e$ is not a digit;
the escape sequence expands to the empty string.
+.It Sy "negative argument, using 0"
+.Pq roff
+A
+.Ic \&shift
+request has a negative argument
+or an argument that is negative due to integer overflow.
+Macro argument numbering remains unchanged.
.It Sy "NOT IMPLEMENTED: Bd -file"
.Pq mdoc
For security reasons, the
request is neither a single ASCII character
nor a single character escape sequence.
The request is ignored including all its arguments.
+.It Sy "skipping unusable escape sequence"
+.Pq roff
+The first argument of an
+.Ic mc
+request is neither a single ASCII character
+nor a single character escape sequence.
+All arguments are ignored and printing of a margin character is disabled.
.It Sy "missing manual name, using \(dq\(dq"
.Pq mdoc
The first call to
.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 charcters 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"