]> git.cameronkatri.com Git - mandoc.git/blob - mandoc.1
Let -h imply -c (that is, not use the pager).
[mandoc.git] / mandoc.1
1 .\" $Id: mandoc.1,v 1.122 2014/11/11 02:43:41 schwarze Exp $
2 .\"
3 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
4 .\" Copyright (c) 2012, 2014 Ingo Schwarze <schwarze@openbsd.org>
5 .\"
6 .\" Permission to use, copy, modify, and distribute this software for any
7 .\" purpose with or without fee is hereby granted, provided that the above
8 .\" copyright notice and this permission notice appear in all copies.
9 .\"
10 .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 .\"
18 .Dd $Mdocdate: November 11 2014 $
19 .Dt MANDOC 1
20 .Os
21 .Sh NAME
22 .Nm mandoc
23 .Nd format and display UNIX manuals
24 .Sh SYNOPSIS
25 .Nm mandoc
26 .Op Fl acfhklV
27 .Sm off
28 .Op Fl I Cm os Li = Ar name
29 .Sm on
30 .Op Fl K Ns Ar encoding
31 .Op Fl m Ns Ar format
32 .Op Fl O Ns Ar option
33 .Op Fl T Ns Ar output
34 .Op Fl W Ns Ar level
35 .Op Ar
36 .Sh DESCRIPTION
37 The
38 .Nm
39 utility formats
40 .Ux
41 manual pages for display.
42 .Pp
43 By default,
44 .Nm
45 reads
46 .Xr mdoc 7
47 or
48 .Xr man 7
49 text from stdin, implying
50 .Fl m Ns Cm andoc ,
51 and produces
52 .Fl T Ns Cm ascii
53 output.
54 .Pp
55 The options are as follows:
56 .Bl -tag -width Ds
57 .It Fl a
58 If the standard output is a terminal device and
59 .Fl c
60 is not specified, use
61 .Xr more 1
62 to paginate the output, just like
63 .Xr man 1
64 would.
65 .It Fl c
66 Copy the formatted manual pages to the standard output without using
67 .Xr more 1
68 to paginate them.
69 This is the default.
70 It can be specified to override
71 .Fl a .
72 .It Fl f
73 A synonym for
74 .Xr whatis 1 .
75 This overrides any earlier
76 .Fl k
77 and
78 .Fl l
79 options.
80 .Sm off
81 .It Fl I Cm os Li = Ar name
82 .Sm on
83 Override the default operating system
84 .Ar name
85 for the
86 .Xr mdoc 7
87 .Sq \&Os
88 macro.
89 .It Fl h
90 Display only the SYNOPSIS lines.
91 Implies
92 .Fl c .
93 .It Fl K Ns Ar encoding
94 Specify the input encoding.
95 The supported
96 .Ar encoding
97 arguments are
98 .Cm us-ascii ,
99 .Cm iso-8859-1 ,
100 and
101 .Cm utf-8 .
102 If not specified, autodetection uses the first match:
103 .Bl -tag -width iso-8859-1
104 .It Cm utf-8
105 if the first three bytes of the input file
106 are the UTF-8 byte order mark (BOM, 0xefbbbf)
107 .It Ar encoding
108 if the first or second line of the input file matches the
109 .Sy emacs
110 mode line format
111 .Pp
112 .D1 .\e" -*- Oo ...; Oc coding: Ar encoding ; No -*-
113 .It Cm utf-8
114 if the first non-ASCII byte in the file introduces a valid UTF-8 sequence
115 .It Cm iso-8859-1
116 otherwise
117 .El
118 .It Fl k
119 A synonym for
120 .Xr apropos 1 .
121 This overrides any earlier
122 .Fl f
123 and
124 .Fl l
125 options.
126 .It Fl l
127 A synonym for
128 .Fl a .
129 Also reverts any earlier
130 .Fl f
131 and
132 .Fl k
133 options.
134 .It Fl m Ns Ar format
135 Input format.
136 See
137 .Sx Input Formats
138 for available formats.
139 Defaults to
140 .Fl m Ns Cm andoc .
141 .It Fl O Ns Ar option
142 Comma-separated output options.
143 .It Fl T Ns Ar output
144 Output format.
145 See
146 .Sx Output Formats
147 for available formats.
148 Defaults to
149 .Fl T Ns Cm ascii .
150 .It Fl V
151 Print version and exit.
152 .It Fl W Ns Ar level
153 Specify the minimum message
154 .Ar level
155 to be reported on the standard error output and to affect the exit status.
156 The
157 .Ar level
158 can be
159 .Cm warning ,
160 .Cm error ,
161 or
162 .Cm fatal .
163 The default is
164 .Fl W Ns Cm fatal ;
165 .Fl W Ns Cm all
166 is an alias for
167 .Fl W Ns Cm warning .
168 See
169 .Sx EXIT STATUS
170 and
171 .Sx DIAGNOSTICS
172 for details.
173 .Pp
174 The special option
175 .Fl W Ns Cm stop
176 tells
177 .Nm
178 to exit after parsing a file that causes warnings or errors of at least
179 the requested level.
180 No formatted output will be produced from that file.
181 If both a
182 .Ar level
183 and
184 .Cm stop
185 are requested, they can be joined with a comma, for example
186 .Fl W Ns Cm error , Ns Cm stop .
187 .It Ar file
188 Read input from zero or more files.
189 If unspecified, reads from stdin.
190 If multiple files are specified,
191 .Nm
192 will halt with the first failed parse.
193 .El
194 .Pp
195 In
196 .Fl f
197 and
198 .Fl k
199 mode,
200 .Nm
201 also supports the options
202 .Fl CMmOSsw
203 described in the
204 .Xr apropos 1
205 manual.
206 .Ss Input Formats
207 The
208 .Nm
209 utility accepts
210 .Xr mdoc 7
211 and
212 .Xr man 7
213 input with
214 .Fl m Ns Cm doc
215 and
216 .Fl m Ns Cm an ,
217 respectively.
218 The
219 .Xr mdoc 7
220 format is
221 .Em strongly
222 recommended;
223 .Xr man 7
224 should only be used for legacy manuals.
225 .Pp
226 A third option,
227 .Fl m Ns Cm andoc ,
228 which is also the default, determines encoding on-the-fly: if the first
229 non-comment macro is
230 .Sq \&Dd
231 or
232 .Sq \&Dt ,
233 the
234 .Xr mdoc 7
235 parser is used; otherwise, the
236 .Xr man 7
237 parser is used.
238 .Pp
239 If multiple
240 files are specified with
241 .Fl m Ns Cm andoc ,
242 each has its file-type determined this way.
243 If multiple files are
244 specified and
245 .Fl m Ns Cm doc
246 or
247 .Fl m Ns Cm an
248 is specified, then this format is used exclusively.
249 .Ss Output Formats
250 The
251 .Nm
252 utility accepts the following
253 .Fl T
254 arguments, which correspond to output modes:
255 .Bl -tag -width "-Tlocale"
256 .It Fl T Ns Cm ascii
257 Produce 7-bit ASCII output.
258 This is the default.
259 See
260 .Sx ASCII Output .
261 .It Fl T Ns Cm html
262 Produce HTML5, CSS1, and MathML output.
263 See
264 .Sx HTML Output .
265 .It Fl T Ns Cm lint
266 Parse only: produce no output.
267 Implies
268 .Fl W Ns Cm warning .
269 .It Fl T Ns Cm locale
270 Encode output using the current locale.
271 See
272 .Sx Locale Output .
273 .It Fl T Ns Cm man
274 Produce
275 .Xr man 7
276 format output.
277 See
278 .Sx Man Output .
279 .It Fl T Ns Cm pdf
280 Produce PDF output.
281 See
282 .Sx PDF Output .
283 .It Fl T Ns Cm ps
284 Produce PostScript output.
285 See
286 .Sx PostScript Output .
287 .It Fl T Ns Cm tree
288 Produce an indented parse tree.
289 .It Fl T Ns Cm utf8
290 Encode output in the UTF\-8 multi-byte format.
291 See
292 .Sx UTF\-8 Output .
293 .It Fl T Ns Cm xhtml
294 This is a synonym for
295 .Fl T Ns Cm html .
296 .El
297 .Pp
298 If multiple input files are specified, these will be processed by the
299 corresponding filter in-order.
300 .Ss ASCII Output
301 Output produced by
302 .Fl T Ns Cm ascii ,
303 which is the default, is rendered in standard 7-bit ASCII documented in
304 .Xr ascii 7 .
305 .Pp
306 Font styles are applied by using back-spaced encoding such that an
307 underlined character
308 .Sq c
309 is rendered as
310 .Sq _ Ns \e[bs] Ns c ,
311 where
312 .Sq \e[bs]
313 is the back-space character number 8.
314 Emboldened characters are rendered as
315 .Sq c Ns \e[bs] Ns c .
316 .Pp
317 The special characters documented in
318 .Xr mandoc_char 7
319 are rendered best-effort in an ASCII equivalent.
320 If no equivalent is found,
321 .Sq \&?
322 is used instead.
323 .Pp
324 Output width is limited to 78 visible columns unless literal input lines
325 exceed this limit.
326 .Pp
327 The following
328 .Fl O
329 arguments are accepted:
330 .Bl -tag -width Ds
331 .It Cm indent Ns = Ns Ar indent
332 The left margin for normal text is set to
333 .Ar indent
334 blank characters instead of the default of five for
335 .Xr mdoc 7
336 and seven for
337 .Xr man 7 .
338 Increasing this is not recommended; it may result in degraded formatting,
339 for example overfull lines or ugly line breaks.
340 .It Cm width Ns = Ns Ar width
341 The output width is set to
342 .Ar width ,
343 which will normalise to \(>=60.
344 .El
345 .Ss HTML Output
346 Output produced by
347 .Fl T Ns Cm html
348 conforms to HTML5 using optional self-closing tags.
349 Default styles use only CSS1.
350 Equations rendered from
351 .Xr eqn 7
352 blocks use MathML.
353 .Pp
354 The
355 .Pa example.style.css
356 file documents style-sheet classes available for customising output.
357 If a style-sheet is not specified with
358 .Fl O Ns Ar style ,
359 .Fl T Ns Cm html
360 defaults to simple output (via an embedded style-sheet)
361 readable in any graphical or text-based web
362 browser.
363 .Pp
364 Special characters are rendered in decimal-encoded UTF\-8.
365 .Pp
366 The following
367 .Fl O
368 arguments are accepted:
369 .Bl -tag -width Ds
370 .It Cm fragment
371 Omit the
372 .Aq !DOCTYPE
373 declaration and the
374 .Aq html ,
375 .Aq head ,
376 and
377 .Aq body
378 elements and only emit the subtree below the
379 .Aq body
380 element.
381 The
382 .Cm style
383 argument will be ignored.
384 This is useful when embedding manual content within existing documents.
385 .It Cm includes Ns = Ns Ar fmt
386 The string
387 .Ar fmt ,
388 for example,
389 .Ar ../src/%I.html ,
390 is used as a template for linked header files (usually via the
391 .Sq \&In
392 macro).
393 Instances of
394 .Sq \&%I
395 are replaced with the include filename.
396 The default is not to present a
397 hyperlink.
398 .It Cm man Ns = Ns Ar fmt
399 The string
400 .Ar fmt ,
401 for example,
402 .Ar ../html%S/%N.%S.html ,
403 is used as a template for linked manuals (usually via the
404 .Sq \&Xr
405 macro).
406 Instances of
407 .Sq \&%N
408 and
409 .Sq %S
410 are replaced with the linked manual's name and section, respectively.
411 If no section is included, section 1 is assumed.
412 The default is not to
413 present a hyperlink.
414 .It Cm style Ns = Ns Ar style.css
415 The file
416 .Ar style.css
417 is used for an external style-sheet.
418 This must be a valid absolute or
419 relative URI.
420 .El
421 .Ss Locale Output
422 Locale-depending output encoding is triggered with
423 .Fl T Ns Cm locale .
424 This option is not available on all systems: systems without locale
425 support, or those whose internal representation is not natively UCS-4,
426 will fall back to
427 .Fl T Ns Cm ascii .
428 See
429 .Sx ASCII Output
430 for font style specification and available command-line arguments.
431 .Ss Man Output
432 Translate input format into
433 .Xr man 7
434 output format.
435 This is useful for distributing manual sources to legacy systems
436 lacking
437 .Xr mdoc 7
438 formatters.
439 .Pp
440 If
441 .Xr mdoc 7
442 is passed as input, it is translated into
443 .Xr man 7 .
444 If the input format is
445 .Xr man 7 ,
446 the input is copied to the output, expanding any
447 .Xr roff 7
448 .Sq so
449 requests.
450 The parser is also run, and as usual, the
451 .Fl W
452 level controls which
453 .Sx DIAGNOSTICS
454 are displayed before copying the input to the output.
455 .Ss PDF Output
456 PDF-1.1 output may be generated by
457 .Fl T Ns Cm pdf .
458 See
459 .Sx PostScript Output
460 for
461 .Fl O
462 arguments and defaults.
463 .Ss PostScript Output
464 PostScript
465 .Qq Adobe-3.0
466 Level-2 pages may be generated by
467 .Fl T Ns Cm ps .
468 Output pages default to letter sized and are rendered in the Times font
469 family, 11-point.
470 Margins are calculated as 1/9 the page length and width.
471 Line-height is 1.4m.
472 .Pp
473 Special characters are rendered as in
474 .Sx ASCII Output .
475 .Pp
476 The following
477 .Fl O
478 arguments are accepted:
479 .Bl -tag -width Ds
480 .It Cm paper Ns = Ns Ar name
481 The paper size
482 .Ar name
483 may be one of
484 .Ar a3 ,
485 .Ar a4 ,
486 .Ar a5 ,
487 .Ar legal ,
488 or
489 .Ar letter .
490 You may also manually specify dimensions as
491 .Ar NNxNN ,
492 width by height in millimetres.
493 If an unknown value is encountered,
494 .Ar letter
495 is used.
496 .El
497 .Ss UTF\-8 Output
498 Use
499 .Fl T Ns Cm utf8
500 to force a UTF\-8 locale.
501 See
502 .Sx Locale Output
503 for details and options.
504 .Sh ENVIRONMENT
505 .Bl -tag -width MANPAGER
506 .It Ev MANPAGER
507 Any non-empty value of the environment variable
508 .Ev MANPAGER
509 will be used instead of the standard pagination program,
510 .Xr more 1 .
511 .It Ev PAGER
512 Specifies the pagination program to use when
513 .Ev MANPAGER
514 is not defined.
515 If neither PAGER nor MANPAGER is defined,
516 .Pa /usr/bin/more Fl s
517 will be used.
518 .El
519 .Sh EXIT STATUS
520 The
521 .Nm
522 utility exits with one of the following values, controlled by the message
523 .Ar level
524 associated with the
525 .Fl W
526 option:
527 .Pp
528 .Bl -tag -width Ds -compact
529 .It 0
530 No warnings or errors occurred, or those that did were ignored because
531 they were lower than the requested
532 .Ar level .
533 .It 2
534 At least one warning occurred, but no error, and
535 .Fl W Ns Cm warning
536 was specified.
537 .It 3
538 At least one parsing error occurred, but no fatal error, and
539 .Fl W Ns Cm error
540 or
541 .Fl W Ns Cm warning
542 was specified.
543 .It 4
544 A fatal parsing error occurred.
545 .It 5
546 Invalid command line arguments were specified.
547 No input files have been read.
548 .It 6
549 An operating system error occurred, for example memory exhaustion or an
550 error accessing input files.
551 Such errors cause
552 .Nm
553 to exit at once, possibly in the middle of parsing or formatting a file.
554 .El
555 .Pp
556 Note that selecting
557 .Fl T Ns Cm lint
558 output mode implies
559 .Fl W Ns Cm warning .
560 .Sh EXAMPLES
561 To page manuals to the terminal:
562 .Pp
563 .Dl $ mandoc \-Wall,stop mandoc.1 2\*(Gt&1 | less
564 .Dl $ mandoc mandoc.1 mdoc.3 mdoc.7 | less
565 .Pp
566 To produce HTML manuals with
567 .Ar style.css
568 as the style-sheet:
569 .Pp
570 .Dl $ mandoc \-Thtml -Ostyle=style.css mdoc.7 \*(Gt mdoc.7.html
571 .Pp
572 To check over a large set of manuals:
573 .Pp
574 .Dl $ mandoc \-Tlint `find /usr/src -name \e*\e.[1-9]`
575 .Pp
576 To produce a series of PostScript manuals for A4 paper:
577 .Pp
578 .Dl $ mandoc \-Tps \-Opaper=a4 mdoc.7 man.7 \*(Gt manuals.ps
579 .Pp
580 Convert a modern
581 .Xr mdoc 7
582 manual to the older
583 .Xr man 7
584 format, for use on systems lacking an
585 .Xr mdoc 7
586 parser:
587 .Pp
588 .Dl $ mandoc \-Tman foo.mdoc \*(Gt foo.man
589 .Sh DIAGNOSTICS
590 Messages displayed by
591 .Nm
592 follow this format:
593 .Pp
594 .D1 Nm Ns : Ar file : Ns Ar line : Ns Ar column : level : message : macro args
595 .Pp
596 Line and column numbers start at 1.
597 Both are omitted for messages referring to an input file as a whole.
598 Macro names and arguments are omitted where meaningless.
599 Fatal messages about invalid command line arguments
600 or operating system errors, for example when memory is exhausted,
601 may also omit the
602 .Ar file
603 and
604 .Ar level
605 fields.
606 .Pp
607 Message levels have the following meanings:
608 .Bl -tag -width "warning"
609 .It Cm syserr
610 Opening or reading an input file failed, so the parser cannot
611 even be started and no output is produced from that input file.
612 .It Cm fatal
613 The parser is unable to parse a given input file at all.
614 No formatted output is produced from that input file.
615 .It Cm error
616 An input file contains syntax that cannot be safely interpreted,
617 either because it is invalid or because
618 .Nm
619 does not implement it yet.
620 By discarding part of the input or inserting missing tokens,
621 the parser is able to continue, and the error does not prevent
622 generation of formatted output, but typically, preparing that
623 output involves information loss, broken document structure
624 or unintended formatting.
625 .It Cm warning
626 An input file uses obsolete, discouraged or non-portable syntax.
627 All the same, the meaning of the input is unambiguous and a correct
628 rendering can be produced.
629 Documents causing warnings may render poorly when using other
630 formatting tools instead of
631 .Nm .
632 .El
633 .Pp
634 Messages of the
635 .Cm warning
636 and
637 .Cm error
638 levels are hidden unless their level, or a lower level, is requested using a
639 .Fl W
640 option or
641 .Fl T Ns Cm lint
642 output mode.
643 .Ss Warnings related to the document prologue
644 .Bl -ohang
645 .It Sy "missing manual title, using UNTITLED"
646 .Pq mdoc
647 A
648 .Ic \&Dt
649 macro has no arguments, or there is no
650 .Ic \&Dt
651 macro before the first non-prologue macro.
652 .It Sy "missing manual title, using \(dq\(dq"
653 .Pq man
654 There is no
655 .Ic \&TH
656 macro, or it has no arguments.
657 .It Sy "lower case character in document title"
658 .Pq mdoc , man
659 The title is still used as given in the
660 .Ic \&Dt
661 or
662 .Ic \&TH
663 macro.
664 .It Sy "missing manual section, using \(dq\(dq"
665 .Pq mdoc , man
666 A
667 .Ic \&Dt
668 or
669 .Ic \&TH
670 macro lacks the mandatory section argument.
671 .It Sy "unknown manual section"
672 .Pq mdoc
673 The section number in a
674 .Ic \&Dt
675 line is invalid, but still used.
676 .It Sy "unknown manual volume or arch"
677 .Pq mdoc
678 The volume name in a
679 .Ic \&Dt
680 line is invalid, but still used.
681 The manual is assumed to be architecture-independent.
682 .It Sy "missing date, using today's date"
683 .Pq mdoc, man
684 The document was parsed as
685 .Xr mdoc 7
686 and it has no
687 .Ic \&Dd
688 macro, or the
689 .Ic \&Dd
690 macro has no arguments or only empty arguments;
691 or the document was parsed as
692 .Xr man 7
693 and it has no
694 .Ic \&TH
695 macro, or the
696 .Ic \&TH
697 macro has less than three arguments or its third argument is empty.
698 .It Sy "cannot parse date, using it verbatim"
699 .Pq mdoc , man
700 The date given in a
701 .Ic \&Dd
702 or
703 .Ic \&TH
704 macro does not follow the conventional format.
705 .It Sy "missing Os macro, using \(dq\(dq"
706 .Pq mdoc
707 The default or current system is not shown in this case.
708 .It Sy "duplicate prologue macro"
709 .Pq mdoc
710 One of the prologue macros occurs more than once.
711 The last instance overrides all previous ones.
712 .It Sy "late prologue macro"
713 .Pq mdoc
714 A
715 .Ic \&Dd
716 or
717 .Ic \&Os
718 macro occurs after some non-prologue macro, but still takes effect.
719 .It Sy "skipping late title macro"
720 .Pq mdoc
721 The
722 .Ic \&Dt
723 macro can only occur before the first non-prologue macro
724 because traditional formatters write the page header
725 before parsing the document body.
726 Even though this technical restriction does not apply to
727 .Nm ,
728 traditional semantics is preserved.
729 The late macro is discarded including its arguments.
730 .It Sy "prologue macros out of order"
731 .Pq mdoc
732 The prologue macros are not given in the conventional order
733 .Ic \&Dd ,
734 .Ic \&Dt ,
735 .Ic \&Os .
736 All three macros are used even when given in another order.
737 .El
738 .Ss Warnings regarding document structure
739 .Bl -ohang
740 .It Sy ".so is fragile, better use ln(1)"
741 .Pq roff
742 Including files only works when the parser program runs with the correct
743 current working directory.
744 .It Sy "no document body"
745 .Pq mdoc , man
746 The document body contains neither text nor macros.
747 An empty document is shown, consisting only of a header and a footer line.
748 .It Sy "content before first section header"
749 .Pq mdoc , man
750 Some macros or text precede the first
751 .Ic \&Sh
752 or
753 .Ic \&SH
754 section header.
755 The offending macros and text are parsed and added to the top level
756 of the syntax tree, outside any section block.
757 .It Sy "first section is not NAME"
758 .Pq mdoc
759 The argument of the first
760 .Ic \&Sh
761 macro is not
762 .Sq NAME .
763 This may confuse
764 .Xr makewhatis 8
765 and
766 .Xr apropos 1 .
767 .It Sy "bad NAME section contents"
768 .Pq mdoc
769 The last node in the NAME section is not an
770 .Ic \&Nd
771 macro, or any preceding macro is not
772 .Ic \&Nm ,
773 or the NAME section is completely empty.
774 This may confuse
775 .Xr makewhatis 8
776 and
777 .Xr apropos 1 .
778 .It Sy "sections out of conventional order"
779 .Pq mdoc
780 A standard section occurs after another section it usually precedes.
781 All section titles are used as given,
782 and the order of sections is not changed.
783 .It Sy "duplicate section title"
784 .Pq mdoc
785 The same standard section title occurs more than once.
786 .It Sy "unexpected section"
787 .Pq mdoc
788 A standard section header occurs in a section of the manual
789 where it normally isn't useful.
790 .It Sy "unusual Xr order"
791 .Pq mdoc
792 In the SEE ALSO section, an
793 .Ic \&Xr
794 macro with a lower section number follows one with a higher number,
795 or two
796 .Ic \&Xr
797 macros refering to the same section are out of alphabetical order.
798 .It Sy "unusual Xr punctuation"
799 .Pq mdoc
800 In the SEE ALSO section, punctuation between two
801 .Ic \&Xr
802 macros differs from a single comma, or there is trailing punctuation
803 after the last
804 .Ic \&Xr
805 macro.
806 .It Sy "AUTHORS section without An macro"
807 .Pq mdoc
808 An AUTHORS sections contains no
809 .Ic \&An
810 macros, or only empty ones.
811 Probably, there are author names lacking markup.
812 .El
813 .Ss "Warnings related to macros and nesting"
814 .Bl -ohang
815 .It Sy "obsolete macro"
816 .Pq mdoc
817 See the
818 .Xr mdoc 7
819 manual for replacements.
820 .It Sy "skipping paragraph macro"
821 In
822 .Xr mdoc 7
823 documents, this happens
824 .Bl -dash -compact
825 .It
826 at the beginning and end of sections and subsections
827 .It
828 right before non-compact lists and displays
829 .It
830 at the end of items in non-column, non-compact lists
831 .It
832 and for multiple consecutive paragraph macros.
833 .El
834 In
835 .Xr man 7
836 documents, it happens
837 .Bl -dash -compact
838 .It
839 for empty
840 .Ic \&P ,
841 .Ic \&PP ,
842 and
843 .Ic \&LP
844 macros
845 .It
846 for
847 .Ic \&IP
848 macros having neither head nor body arguments
849 .It
850 for
851 .Ic \&br
852 or
853 .Ic \&sp
854 right after
855 .Ic \&SH
856 or
857 .Ic \&SS
858 .El
859 .It Sy "moving paragraph macro out of list"
860 .Pq mdoc
861 A list item in a
862 .Ic \&Bl
863 list contains a trailing paragraph macro.
864 The paragraph macro is moved after the end of the list.
865 .It Sy "skipping no-space macro"
866 .Pq mdoc
867 An input line begins with an
868 .Ic \&Ns
869 macro.
870 The macro is ignored.
871 .It Sy "blocks badly nested"
872 .Pq mdoc
873 If two blocks intersect, one should completely contain the other.
874 Otherwise, rendered output is likely to look strange in any output
875 format, and rendering in SGML-based output formats is likely to be
876 outright wrong because such languages do not support badly nested
877 blocks at all.
878 Typical examples of badly nested blocks are
879 .Qq Ic \&Ao \&Bo \&Ac \&Bc
880 and
881 .Qq Ic \&Ao \&Bq \&Ac .
882 In these examples,
883 .Ic \&Ac
884 breaks
885 .Ic \&Bo
886 and
887 .Ic \&Bq ,
888 respectively.
889 .It Sy "nested displays are not portable"
890 .Pq mdoc
891 A
892 .Ic \&Bd ,
893 .Ic \&D1 ,
894 or
895 .Ic \&Dl
896 display occurs nested inside another
897 .Ic \&Bd
898 display.
899 This works with
900 .Nm ,
901 but fails with most other implementations.
902 .It Sy "moving content out of list"
903 .Pq mdoc
904 A
905 .Ic \&Bl
906 list block contains text or macros before the first
907 .Ic \&It
908 macro.
909 The offending children are moved before the beginning of the list.
910 .It Sy ".Vt block has child macro"
911 .Pq mdoc
912 The
913 .Ic \&Vt
914 macro supports plain text arguments only.
915 Formatting may be ugly and semantic searching
916 for the affected content might not work.
917 .It Sy "fill mode already enabled, skipping"
918 .Pq man
919 A
920 .Ic \&fi
921 request occurs even though the document is still in fill mode,
922 or already switched back to fill mode.
923 It has no effect.
924 .It Sy "fill mode already disabled, skipping"
925 .Pq man
926 An
927 .Ic \&nf
928 request occurs even though the document already switched to no-fill mode
929 and did not switch back to fill mode yet.
930 It has no effect.
931 .It Sy "line scope broken"
932 .Pq man
933 While parsing the next-line scope of the previous macro,
934 another macro is found that prematurely terminates the previous one.
935 The previous, interrupted macro is deleted from the parse tree.
936 .El
937 .Ss "Warnings related to missing arguments"
938 .Bl -ohang
939 .It Sy "skipping empty request"
940 .Pq roff , eqn
941 The macro name is missing from a macro definition request,
942 or an
943 .Xr eqn 7
944 control statement or operation keyword lacks its required argument.
945 .It Sy "conditional request controls empty scope"
946 .Pq roff
947 A conditional request is only useful if any of the following
948 follows it on the same logical input line:
949 .Bl -dash -compact
950 .It
951 The
952 .Sq \e{
953 keyword to open a multi-line scope.
954 .It
955 A request or macro or some text, resulting in a single-line scope.
956 .It
957 The immediate end of the logical line without any intervening whitespace,
958 resulting in next-line scope.
959 .El
960 Here, a conditional request is followed by trailing whitespace only,
961 and there is no other content on its logical input line.
962 Note that it doesn't matter whether the logical input line is split
963 across multiple physical input lines using
964 .Sq \e
965 line continuation characters.
966 This is one of the rare cases
967 where trailing whitespace is syntactically significant.
968 The conditional request controls a scope containing whitespace only,
969 so it is unlikely to have a significant effect,
970 except that it may control a following
971 .Ic \&el
972 clause.
973 .It Sy "skipping empty macro"
974 .Pq mdoc
975 The indicated macro has no arguments and hence no effect.
976 .It Sy "empty argument, using 0n"
977 .Pq mdoc
978 The required width is missing after
979 .Ic \&Bd
980 or
981 .Ic \&Bl
982 .Fl offset
983 or
984 .Fl width.
985 .It Sy "argument count wrong"
986 .Pq mdoc , man
987 The indicated macro has too few or too many arguments.
988 The syntax tree will contain the wrong number of arguments as given.
989 Formatting behaviour depends on the specific macro in question.
990 Note that the same message may also occur as an ERROR, see below.
991 .It Sy "missing display type, using -ragged"
992 .Pq mdoc
993 The
994 .Ic \&Bd
995 macro is invoked without the required display type.
996 .It Sy "list type is not the first argument"
997 .Pq mdoc
998 In a
999 .Ic \&Bl
1000 macro, at least one other argument precedes the type argument.
1001 The
1002 .Nm
1003 utility copes with any argument order, but some other
1004 .Xr mdoc 7
1005 implementations do not.
1006 .It Sy "missing -width in -tag list, using 8n"
1007 .Pq mdoc
1008 Every
1009 .Ic \&Bl
1010 macro having the
1011 .Fl tag
1012 argument requires
1013 .Fl width ,
1014 too.
1015 .It Sy "missing utility name, using \(dq\(dq"
1016 .Pq mdoc
1017 The
1018 .Ic \&Ex Fl std
1019 macro is called without an argument before
1020 .Ic \&Nm
1021 has first been called with an argument.
1022 .It Sy "empty head in list item"
1023 .Pq mdoc
1024 In a
1025 .Ic \&Bl
1026 .Fl diag ,
1027 .Fl hang ,
1028 .Fl inset ,
1029 .Fl ohang ,
1030 or
1031 .Fl tag
1032 list, an
1033 .Ic \&It
1034 macro lacks the required argument.
1035 The item head is left empty.
1036 .It Sy "empty list item"
1037 .Pq mdoc
1038 In a
1039 .Ic \&Bl
1040 .Fl bullet ,
1041 .Fl dash ,
1042 .Fl enum ,
1043 or
1044 .Fl hyphen
1045 list, an
1046 .Ic \&It
1047 block is empty.
1048 An empty list item is shown.
1049 .It Sy "missing font type"
1050 .Pq mdoc
1051 A
1052 .Ic \&Bf
1053 macro has no argument.
1054 It switches to the default font,
1055 .Cm \efR .
1056 .It Sy "unknown font type"
1057 .Pq mdoc
1058 The
1059 .Ic \&Bf
1060 argument is invalid.
1061 The default font
1062 .Cm \efR
1063 is used instead.
1064 .It Sy "missing -std argument, adding it"
1065 .Pq mdoc
1066 An
1067 .Ic \&Ex
1068 or
1069 .Ic \&Rv
1070 macro lacks the required
1071 .Fl std
1072 argument.
1073 The
1074 .Nm
1075 utility assumes
1076 .Fl std
1077 even when it is not specified, but other implementations may not.
1078 .It Sy "missing eqn box, using \(dq\(dq"
1079 .Pq eqn
1080 A diacritic mark or a binary operator is found,
1081 but there is nothing to the left of it.
1082 An empty box is inserted.
1083 .El
1084 .Ss "Warnings related to bad macro arguments"
1085 .Bl -ohang
1086 .It Sy "unterminated quoted argument"
1087 .Pq roff
1088 Macro arguments can be enclosed in double quote characters
1089 such that space characters and macro names contained in the quoted
1090 argument need not be escaped.
1091 The closing quote of the last argument of a macro can be omitted.
1092 However, omitting it is not recommended because it makes the code
1093 harder to read.
1094 .It Sy "duplicate argument"
1095 .Pq mdoc
1096 A
1097 .Ic \&Bd
1098 or
1099 .Ic \&Bl
1100 macro has more than one
1101 .Fl compact ,
1102 more than one
1103 .Fl offset ,
1104 or more than one
1105 .Fl width
1106 argument.
1107 All but the last instances of these arguments are ignored.
1108 .It Sy "skipping duplicate argument"
1109 .Pq mdoc
1110 An
1111 .Ic \&An
1112 macro has more than one
1113 .Fl split
1114 or
1115 .Fl nosplit
1116 argument.
1117 All but the first of these arguments are ignored.
1118 .It Sy "skipping duplicate display type"
1119 .Pq mdoc
1120 A
1121 .Ic \&Bd
1122 macro has more than one type argument; the first one is used.
1123 .It Sy "skipping duplicate list type"
1124 .Pq mdoc
1125 A
1126 .Ic \&Bl
1127 macro has more than one type argument; the first one is used.
1128 .It Sy "skipping -width argument"
1129 .Pq mdoc
1130 A
1131 .Ic \&Bl
1132 .Fl column ,
1133 .Fl diag ,
1134 .Fl ohang ,
1135 .Fl inset ,
1136 or
1137 .Fl item
1138 list has a
1139 .Fl width
1140 argument.
1141 That has no effect.
1142 .It Sy "unknown AT&T UNIX version"
1143 .Pq mdoc
1144 An
1145 .Ic \&At
1146 macro has an invalid argument.
1147 It is used verbatim, with
1148 .Qq "AT&T UNIX "
1149 prefixed to it.
1150 .It Sy "comma in function argument"
1151 .Pq mdoc
1152 An argument of an
1153 .Ic \&Fa
1154 or
1155 .Ic \&Fn
1156 macro contains a comma; it should probably be split into two arguments.
1157 .It Sy "parenthesis in function name"
1158 .Pq mdoc
1159 The first argument of an
1160 .Ic \&Fc
1161 or
1162 .Ic \&Fn
1163 macro contains an opening or closing parenthesis; that's probably wrong,
1164 parentheses are added automatically.
1165 .It Sy "invalid content in Rs block"
1166 .Pq mdoc
1167 An
1168 .Ic \&Rs
1169 block contains plain text or non-% macros.
1170 The bogus content is left in the syntax tree.
1171 Formatting may be poor.
1172 .It Sy "invalid Boolean argument"
1173 .Pq mdoc
1174 An
1175 .Ic \&Sm
1176 macro has an argument other than
1177 .Cm on
1178 or
1179 .Cm off .
1180 The invalid argument is moved out of the macro, which leaves the macro
1181 empty, causing it to toggle the spacing mode.
1182 .It Sy "unknown font, skipping request"
1183 .Pq man , tbl
1184 A
1185 .Xr roff 7
1186 .Ic \&ft
1187 request or a
1188 .Xr tbl 7
1189 .Ic \&f
1190 layout modifier has an unknown
1191 .Ar font
1192 argument.
1193 .El
1194 .Ss "Warnings related to plain text"
1195 .Bl -ohang
1196 .It Sy "blank line in fill mode, using .sp"
1197 .Pq mdoc
1198 The meaning of blank input lines is only well-defined in non-fill mode:
1199 In fill mode, line breaks of text input lines are not supposed to be
1200 significant.
1201 However, for compatibility with groff, blank lines in fill mode
1202 are replaced with
1203 .Ic \&sp
1204 requests.
1205 .It Sy "tab in filled text"
1206 .Pq mdoc , man
1207 The meaning of tab characters is only well-defined in non-fill mode:
1208 In fill mode, whitespace is not supposed to be significant
1209 on text input lines.
1210 As an implementation dependent choice, tab characters on text lines
1211 are passed through to the formatters in any case.
1212 Given that the text before the tab character will be filled,
1213 it is hard to predict which tab stop position the tab will advance to.
1214 .It Sy "whitespace at end of input line"
1215 .Pq mdoc , man , roff
1216 Whitespace at the end of input lines is almost never semantically
1217 significant \(em but in the odd case where it might be, it is
1218 extremely confusing when reviewing and maintaining documents.
1219 .It Sy "bad comment style"
1220 .Pq roff
1221 Comment lines start with a dot, a backslash, and a double-quote character.
1222 The
1223 .Nm
1224 utility treats the line as a comment line even without the backslash,
1225 but leaving out the backslash might not be portable.
1226 .It Sy "invalid escape sequence"
1227 .Pq roff
1228 An escape sequence has an invalid opening argument delimiter, lacks the
1229 closing argument delimiter, or the argument has too few characters.
1230 If the argument is incomplete,
1231 .Ic \e*
1232 and
1233 .Ic \en
1234 expand to an empty string,
1235 .Ic \eB
1236 to the digit
1237 .Sq 0 ,
1238 and
1239 .Ic \ew
1240 to the length of the incomplete argument.
1241 All other invalid escape sequences are ignored.
1242 .It Sy "undefined string, using \(dq\(dq"
1243 .Pq roff
1244 If a string is used without being defined before,
1245 its value is implicitly set to the empty string.
1246 However, defining strings explicitly before use
1247 keeps the code more readable.
1248 .El
1249 .Ss "Errors related to equations"
1250 .Bl -inset -compact
1251 .It "unexpected equation scope closure"
1252 .It "equation scope open on exit"
1253 .It "overlapping equation scopes"
1254 .It "unexpected end of equation"
1255 .El
1256 .Ss "Errors related to tables"
1257 .Bl -inset -compact
1258 .It "bad table syntax"
1259 .It "bad table option"
1260 .It "bad table layout"
1261 .It "no table layout cells specified"
1262 .It "no table data cells specified"
1263 .It "ignore data in cell"
1264 .It "data block still open"
1265 .It "ignoring extra data cells"
1266 .El
1267 .Ss "Errors related to roff, mdoc, and man code"
1268 .Bl -ohang
1269 .It Sy "input stack limit exceeded, infinite loop?"
1270 .Pq roff
1271 Explicit recursion limits are implemented for the following features,
1272 in order to prevent infinite loops:
1273 .Bl -dash -compact
1274 .It
1275 expansion of nested escape sequences
1276 including expansion of strings and number registers,
1277 .It
1278 expansion of nested user-defined macros,
1279 .It
1280 and
1281 .Ic \&so
1282 file inclusion.
1283 .El
1284 When a limit is hit, the output is incorrect, typically losing
1285 some content, but the parser can continue.
1286 .It Sy "skipping bad character"
1287 .Pq mdoc , man , roff
1288 The input file contains a byte that is not a printable
1289 .Xr ascii 7
1290 character.
1291 The message mentions the character number.
1292 The offending byte is replaced with a question mark
1293 .Pq Sq \&? .
1294 Consider editing the input file to replace the byte with an ASCII
1295 transliteration of the intended character.
1296 .It Sy "skipping unknown macro"
1297 .Pq mdoc , man , roff
1298 The first identifier on a request or macro line is neither recognized as a
1299 .Xr roff 7
1300 request, nor as a user-defined macro, nor, respectively, as an
1301 .Xr mdoc 7
1302 or
1303 .Xr man 7
1304 macro.
1305 It may be mistyped or unsupported.
1306 The request or macro is discarded including its arguments.
1307 .It Sy "skipping item outside list"
1308 .Pq mdoc , eqn
1309 An
1310 .Ic \&It
1311 macro occurs outside any
1312 .Ic \&Bl
1313 list, or an
1314 .Xr eqn 7
1315 .Ic above
1316 delimiter occurs outside any pile.
1317 It is discarded including its arguments.
1318 .It Sy "skipping column outside column list"
1319 .Pq mdoc
1320 A
1321 .Ic \&Ta
1322 macro occurs outside any
1323 .Ic \&Bl Fl column
1324 block.
1325 It is discarded including its arguments.
1326 .It Sy "skipping end of block that is not open"
1327 .Pq mdoc , man , eqn , tbl , roff
1328 Various syntax elements can only be used to explicitly close blocks
1329 that have previously been opened.
1330 An
1331 .Xr mdoc 7
1332 block closing macro, a
1333 .Xr man 7
1334 .Ic \&RE
1335 or
1336 .Ic \&UE
1337 macro, an
1338 .Xr eqn 7
1339 right delimiter or closing brace, or the end of an equation, table, or
1340 .Xr roff 7
1341 conditional request is encountered but no matching block is open.
1342 The offending request or macro is discarded.
1343 .It Sy "inserting missing end of block"
1344 .Pq mdoc , tbl
1345 Various
1346 .Xr mdoc 7
1347 macros as well as tables require explicit closing by dedicated macros.
1348 A block that doesn't support bad nesting
1349 ends before all of its children are properly closed.
1350 The open child nodes are closed implicitly.
1351 .It Sy "scope open on exit"
1352 .Pq mdoc , man , eqn , tbl , roff
1353 At the end of the document, an explicit
1354 .Xr mdoc 7
1355 block, a
1356 .Xr man 7
1357 next-line scope or
1358 .Ic \&RS
1359 or
1360 .Ic \&UR
1361 block, an equation, table, or
1362 .Xr roff 7
1363 conditional or ignore block is still open.
1364 The open block is closed implicitly.
1365 .It Sy "escaped character not allowed in a name"
1366 .Pq roff
1367 Macro, string and register identifiers consist of printable,
1368 non-whitespace ASCII characters.
1369 Escape sequences and characters and strings expressed in terms of them
1370 cannot form part of a name.
1371 The first argument of an
1372 .Ic \&am ,
1373 .Ic \&as ,
1374 .Ic \&de ,
1375 .Ic \&ds ,
1376 .Ic \&nr ,
1377 or
1378 .Ic \&rr
1379 request, or any argument of an
1380 .Ic \&rm
1381 request, or the name of a request or user defined macro being called,
1382 is terminated by an escape sequence.
1383 In the cases of
1384 .Ic \&as ,
1385 .Ic \&ds ,
1386 and
1387 .Ic \&nr ,
1388 the request has no effect at all.
1389 In the cases of
1390 .Ic \&am ,
1391 .Ic \&de ,
1392 .Ic \&rr ,
1393 and
1394 .Ic \&rm ,
1395 what was parsed up to this point is used as the arguments to the request,
1396 and the rest of the input line is discarded including the escape sequence.
1397 When parsing for a request or a user-defined macro name to be called,
1398 only the escape sequence is discarded.
1399 The characters preceding it are used as the request or macro name,
1400 the characters following it are used as the arguments to the request or macro.
1401 .It Sy "argument count wrong"
1402 .Pq mdoc , man , roff
1403 The indicated request or macro has too few or too many arguments.
1404 The syntax tree will contain the wrong number of arguments as given.
1405 Formatting behaviour depends on the specific request or macro in question.
1406 Note that the same message may also occur as a WARNING, see above.
1407 .It Sy "missing list type, using -item"
1408 .Pq mdoc
1409 A
1410 .Ic \&Bl
1411 macro fails to specify the list type.
1412 .It Sy "missing manual name, using \(dq\(dq"
1413 .Pq mdoc
1414 The first call to
1415 .Ic \&Nm
1416 lacks the required argument.
1417 .It Sy "uname(3) system call failed, using UNKNOWN"
1418 .Pq mdoc
1419 The
1420 .Ic \&Os
1421 macro is called without arguments, and the
1422 .Xr uname 3
1423 system call failed.
1424 As a workaround,
1425 .Nm
1426 can be compiled with
1427 .Sm off
1428 .Fl D Cm OSNAME=\(dq\e\(dq Ar string Cm \e\(dq\(dq .
1429 .Sm on
1430 .It Sy "unknown standard specifier"
1431 .Pq mdoc
1432 An
1433 .Ic \&St
1434 macro has an unknown argument and is discarded.
1435 .It Sy "skipping request without numeric argument"
1436 .Pq roff , eqn
1437 An
1438 .Ic \&it
1439 request or an
1440 .Xr eqn 7
1441 .Ic \&size
1442 or
1443 .Ic \&gsize
1444 statement has a non-numeric or negative argument or no argument at all.
1445 The invalid request or statement is ignored.
1446 .It Sy "skipping all arguments"
1447 .Pq mdoc , man , eqn , roff
1448 An
1449 .Xr mdoc 7
1450 .Ic \&Bt ,
1451 .Ic \&Ed ,
1452 .Ic \&Ef ,
1453 .Ic \&Ek ,
1454 .Ic \&El ,
1455 .Ic \&Re ,
1456 or
1457 .Ic \&Ud
1458 macro, an
1459 .Ic \&It
1460 macro in a list that don't support item heads, a
1461 .Xr man 7
1462 .Ic \&LP ,
1463 .Ic \&P ,
1464 or
1465 .Ic \&PP
1466 macro, an
1467 .Xr eqn 7
1468 .Ic \&EQ
1469 or
1470 .Ic \&EN
1471 macro, or a
1472 .Xr roff 7
1473 .Sq \&..
1474 block closing request is invoked with at least one argument.
1475 All arguments are ignored.
1476 .It Sy "skipping excess arguments"
1477 .Pq mdoc , roff
1478 The
1479 .Ic \&Bf
1480 macro is invoked with more than one argument, or a request of the
1481 .Ic \&de
1482 family is invoked with more than two arguments.
1483 The excess arguments are ignored.
1484 .El
1485 .Ss FATAL errors
1486 .Bl -ohang
1487 .It Sy "input too large"
1488 .Pq mdoc , man
1489 Currently,
1490 .Nm
1491 cannot handle input files larger than its arbitrary size limit
1492 of 2^31 bytes (2 Gigabytes).
1493 Since useful manuals are always small, this is not a problem in practice.
1494 Parsing is aborted as soon as the condition is detected.
1495 .It Sy "NOT IMPLEMENTED: Bd -file"
1496 .Pq mdoc
1497 For security reasons, the
1498 .Ic \&Bd
1499 macro does not support the
1500 .Fl file
1501 argument.
1502 By requesting the inclusion of a sensitive file, a malicious document
1503 might otherwise trick a privileged user into inadvertently displaying
1504 the file on the screen, revealing the file content to bystanders.
1505 The parser exits immediately.
1506 .It Sy "NOT IMPLEMENTED: .so with absolute path or \(dq..\(dq"
1507 .Pq roff
1508 For security reasons,
1509 .Nm
1510 allows
1511 .Ic \&so
1512 file inclusion requests only with relative paths
1513 and only without ascending to any parent directory.
1514 By requesting the inclusion of a sensitive file, a malicious document
1515 might otherwise trick a privileged user into inadvertently displaying
1516 the file on the screen, revealing the file content to bystanders.
1517 The parser exits immediately.
1518 .It Sy ".so request failed"
1519 .Pq roff
1520 Servicing a
1521 .Ic \&so
1522 request requires reading an external file.
1523 While trying to do so, an
1524 .Xr open 2 ,
1525 .Xr stat 2 ,
1526 or
1527 .Xr read 2
1528 system call failed.
1529 The parser exits immediately.
1530 Before showing this message,
1531 .Nm
1532 always shows another message explaining why the system call failed.
1533 .El
1534 .Sh COMPATIBILITY
1535 This section summarises
1536 .Nm
1537 compatibility with GNU troff.
1538 Each input and output format is separately noted.
1539 .Ss ASCII Compatibility
1540 .Bl -bullet -compact
1541 .It
1542 Unrenderable unicode codepoints specified with
1543 .Sq \e[uNNNN]
1544 escapes are printed as
1545 .Sq \&?
1546 in mandoc.
1547 In GNU troff, these raise an error.
1548 .It
1549 The
1550 .Sq \&Bd \-literal
1551 and
1552 .Sq \&Bd \-unfilled
1553 macros of
1554 .Xr mdoc 7
1555 in
1556 .Fl T Ns Cm ascii
1557 are synonyms, as are \-filled and \-ragged.
1558 .It
1559 In historic GNU troff, the
1560 .Sq \&Pa
1561 .Xr mdoc 7
1562 macro does not underline when scoped under an
1563 .Sq \&It
1564 in the FILES section.
1565 This behaves correctly in
1566 .Nm .
1567 .It
1568 A list or display following the
1569 .Sq \&Ss
1570 .Xr mdoc 7
1571 macro in
1572 .Fl T Ns Cm ascii
1573 does not assert a prior vertical break, just as it doesn't with
1574 .Sq \&Sh .
1575 .It
1576 The
1577 .Sq \&na
1578 .Xr man 7
1579 macro in
1580 .Fl T Ns Cm ascii
1581 has no effect.
1582 .It
1583 Words aren't hyphenated.
1584 .El
1585 .Ss HTML Compatibility
1586 .Bl -bullet -compact
1587 .It
1588 The
1589 .Sq \efP
1590 escape will revert the font to the previous
1591 .Sq \ef
1592 escape, not to the last rendered decoration, which is now dictated by
1593 CSS instead of hard-coded.
1594 It also will not span past the current scope,
1595 for the same reason.
1596 Note that in
1597 .Sx ASCII Output
1598 mode, this will work fine.
1599 .It
1600 The
1601 .Xr mdoc 7
1602 .Sq \&Bl \-hang
1603 and
1604 .Sq \&Bl \-tag
1605 list types render similarly (no break following overreached left-hand
1606 side) due to the expressive constraints of HTML.
1607 .It
1608 The
1609 .Xr man 7
1610 .Sq IP
1611 and
1612 .Sq TP
1613 lists render similarly.
1614 .El
1615 .Sh SEE ALSO
1616 .Xr eqn 7 ,
1617 .Xr man 7 ,
1618 .Xr mandoc_char 7 ,
1619 .Xr mdoc 7 ,
1620 .Xr roff 7 ,
1621 .Xr tbl 7
1622 .Sh AUTHORS
1623 The
1624 .Nm
1625 utility was written by
1626 .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .
1627 .Sh CAVEATS
1628 In
1629 .Fl T Ns Cm html
1630 and
1631 .Fl T Ns Cm xhtml ,
1632 the maximum size of an element attribute is determined by
1633 .Dv BUFSIZ ,
1634 which is usually 1024 bytes.
1635 Be aware of this when setting long link
1636 formats such as
1637 .Fl O Ns Cm style Ns = Ns Ar really/long/link .
1638 .Pp
1639 Nesting elements within next-line element scopes of
1640 .Fl m Ns Cm an ,
1641 such as
1642 .Sq br
1643 within an empty
1644 .Sq B ,
1645 will confuse
1646 .Fl T Ns Cm html
1647 and
1648 .Fl T Ns Cm xhtml
1649 and cause them to forget the formatting of the prior next-line scope.
1650 .Pp
1651 The
1652 .Sq \(aq
1653 control character is an alias for the standard macro control character
1654 and does not emit a line-break as stipulated in GNU troff.