xref: /openbsd-src/share/man/man7/mdoc.7 (revision 4c1e55dc91edd6e69ccc60ce855900fbc12cf34f)
1.\"	$OpenBSD: mdoc.7,v 1.93 2012/06/20 22:00:23 jmc Exp $
2.\"
3.\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
4.\" Copyright (c) 2010, 2011 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: June 20 2012 $
19.Dt MDOC 7
20.Os
21.Sh NAME
22.Nm mdoc
23.Nd semantic markup language for formatting manual pages
24.Sh DESCRIPTION
25The
26.Nm mdoc
27language supports authoring of manual pages for the
28.Xr man 1
29utility by allowing semantic annotations of words, phrases,
30page sections and complete manual pages.
31Such annotations are used by formatting tools to achieve a uniform
32presentation across all manuals written in
33.Nm ,
34and to support hyperlinking if supported by the output medium.
35.Pp
36This reference document describes the structure of manual pages
37and the syntax and usage of the
38.Nm
39language.
40The reference implementation of a parsing and formatting tool is
41.Xr mandoc 1 ;
42the
43.Sx COMPATIBILITY
44section describes compatibility with other implementations.
45.Pp
46In an
47.Nm
48document, lines beginning with the control character
49.Sq \&.
50are called
51.Dq macro lines .
52The first word is the macro name.
53It consists of two or three letters.
54Most macro names begin with a capital letter.
55For a list of available macros, see
56.Sx MACRO OVERVIEW .
57The words following the macro name are arguments to the macro, optionally
58including the names of other, callable macros; see
59.Sx MACRO SYNTAX
60for details.
61.Pp
62Lines not beginning with the control character are called
63.Dq text lines .
64They provide free-form text to be printed; the formatting of the text
65depends on the respective processing context:
66.Bd -literal -offset indent
67\&.Sh Macro lines change control state.
68Text lines are interpreted within the current state.
69.Ed
70.Pp
71Many aspects of the basic syntax of the
72.Nm
73language are based on the
74.Xr roff 7
75language; see the
76.Em LANGUAGE SYNTAX
77and
78.Em MACRO SYNTAX
79sections in the
80.Xr roff 7
81manual for details, in particular regarding
82comments, escape sequences, whitespace, and quoting.
83However, using
84.Xr roff 7
85requests in
86.Nm
87documents is discouraged;
88.Xr mandoc 1
89supports some of them merely for backward compatibility.
90.Sh MANUAL STRUCTURE
91A well-formed
92.Nm
93document consists of a document prologue followed by one or more
94sections.
95.Pp
96The prologue, which consists of the
97.Sx \&Dd ,
98.Sx \&Dt ,
99and
100.Sx \&Os
101macros in that order, is required for every document.
102.Pp
103The first section (sections are denoted by
104.Sx \&Sh )
105must be the NAME section, consisting of at least one
106.Sx \&Nm
107followed by
108.Sx \&Nd .
109.Pp
110Following that, convention dictates specifying at least the
111.Em SYNOPSIS
112and
113.Em DESCRIPTION
114sections, although this varies between manual sections.
115.Pp
116The following is a well-formed skeleton
117.Nm
118file for a utility
119.Qq progname :
120.Bd -literal -offset indent
121\&.Dd $\&Mdocdate$
122\&.Dt PROGNAME section
123\&.Os
124\&.Sh NAME
125\&.Nm progname
126\&.Nd one line about what it does
127\&.\e\(dq .Sh LIBRARY
128\&.\e\(dq For sections 2, 3, & 9 only.
129\&.\e\(dq Not used in OpenBSD.
130\&.Sh SYNOPSIS
131\&.Nm progname
132\&.Op Fl options
133\&.Ar
134\&.Sh DESCRIPTION
135The
136\&.Nm
137utility processes files ...
138\&.\e\(dq .Sh IMPLEMENTATION NOTES
139\&.\e\(dq Not used in OpenBSD.
140\&.\e\(dq .Sh RETURN VALUES
141\&.\e\(dq For sections 2, 3, & 9 only.
142\&.\e\(dq .Sh ENVIRONMENT
143\&.\e\(dq For sections 1, 6, 7, & 8 only.
144\&.\e\(dq .Sh FILES
145\&.\e\(dq .Sh EXIT STATUS
146\&.\e\(dq For sections 1, 6, & 8 only.
147\&.\e\(dq .Sh EXAMPLES
148\&.\e\(dq .Sh DIAGNOSTICS
149\&.\e\(dq For sections 1, 4, 6, 7, & 8 only.
150\&.\e\(dq .Sh ERRORS
151\&.\e\(dq For sections 2, 3, & 9 only.
152\&.\e\(dq .Sh SEE ALSO
153\&.\e\(dq .Xr foobar 1
154\&.\e\(dq .Sh STANDARDS
155\&.\e\(dq .Sh HISTORY
156\&.\e\(dq .Sh AUTHORS
157\&.\e\(dq .Sh CAVEATS
158\&.\e\(dq .Sh BUGS
159\&.\e\(dq .Sh SECURITY CONSIDERATIONS
160\&.\e\(dq Not used in OpenBSD.
161.Ed
162.Pp
163The sections in an
164.Nm
165document are conventionally ordered as they appear above.
166Sections should be composed as follows:
167.Bl -ohang -offset Ds
168.It Em NAME
169The name(s) and a one line description of the documented material.
170The syntax for this as follows:
171.Bd -literal -offset indent
172\&.Nm name0 ,
173\&.Nm name1 ,
174\&.Nm name2
175\&.Nd a one line description
176.Ed
177.Pp
178Multiple
179.Sq \&Nm
180names should be separated by commas.
181.Pp
182The
183.Sx \&Nm
184macro(s) must precede the
185.Sx \&Nd
186macro.
187.Pp
188See
189.Sx \&Nm
190and
191.Sx \&Nd .
192.It Em LIBRARY
193The name of the library containing the documented material, which is
194assumed to be a function in a section 2, 3, or 9 manual.
195The syntax for this is as follows:
196.Bd -literal -offset indent
197\&.Lb libarm
198.Ed
199.Pp
200See
201.Sx \&Lb .
202.It Em SYNOPSIS
203Documents the utility invocation syntax, function call syntax, or device
204configuration.
205.Pp
206For the first, utilities (sections 1, 6, and 8), this is
207generally structured as follows:
208.Bd -literal -offset indent
209\&.Nm bar
210\&.Op Fl v
211\&.Op Fl o Ar file
212\&.Op Ar
213\&.Nm foo
214\&.Op Fl v
215\&.Op Fl o Ar file
216\&.Op Ar
217.Ed
218.Pp
219Commands should be ordered alphabetically.
220.Pp
221For the second, function calls (sections 2, 3, 9):
222.Bd -literal -offset indent
223\&.In header.h
224\&.Vt extern const char *global;
225\&.Ft "char *"
226\&.Fn foo "const char *src"
227\&.Ft "char *"
228\&.Fn bar "const char *src"
229.Ed
230.Pp
231Ordering of
232.Sx \&In ,
233.Sx \&Vt ,
234.Sx \&Fn ,
235and
236.Sx \&Fo
237macros should follow C header-file conventions.
238.Pp
239And for the third, configurations (section 4):
240.Bd -literal -offset indent
241\&.Cd \(dqit* at isa? port 0x2e\(dq
242\&.Cd \(dqit* at isa? port 0x4e\(dq
243.Ed
244.Pp
245Manuals not in these sections generally don't need a
246.Em SYNOPSIS .
247.Pp
248Some macros are displayed differently in the
249.Em SYNOPSIS
250section, particularly
251.Sx \&Nm ,
252.Sx \&Cd ,
253.Sx \&Fd ,
254.Sx \&Fn ,
255.Sx \&Fo ,
256.Sx \&In ,
257.Sx \&Vt ,
258and
259.Sx \&Ft .
260All of these macros are output on their own line.
261If two such dissimilar macros are pairwise invoked (except for
262.Sx \&Ft
263before
264.Sx \&Fo
265or
266.Sx \&Fn ) ,
267they are separated by a vertical space, unless in the case of
268.Sx \&Fo ,
269.Sx \&Fn ,
270and
271.Sx \&Ft ,
272which are always separated by vertical space.
273.Pp
274When text and macros following an
275.Sx \&Nm
276macro starting an input line span multiple output lines,
277all output lines but the first will be indented to align
278with the text immediately following the
279.Sx \&Nm
280macro, up to the next
281.Sx \&Nm ,
282.Sx \&Sh ,
283or
284.Sx \&Ss
285macro or the end of an enclosing block, whichever comes first.
286.It Em DESCRIPTION
287This begins with an expansion of the brief, one line description in
288.Em NAME :
289.Bd -literal -offset indent
290The
291\&.Nm
292utility does this, that, and the other.
293.Ed
294.Pp
295It usually follows with a breakdown of the options (if documenting a
296command), such as:
297.Bd -literal -offset indent
298The arguments are as follows:
299\&.Bl \-tag \-width Ds
300\&.It Fl v
301Print verbose information.
302\&.El
303.Ed
304.Pp
305Manuals not documenting a command won't include the above fragment.
306.Pp
307Since the
308.Em DESCRIPTION
309section usually contains most of the text of a manual, longer manuals
310often use the
311.Sx \&Ss
312macro to form subsections.
313In very long manuals, the
314.Em DESCRIPTION
315may be split into multiple sections, each started by an
316.Sx \&Sh
317macro followed by a non-standard section name, and each having
318several subsections, like in the present
319.Nm
320manual.
321.It Em IMPLEMENTATION NOTES
322Implementation-specific notes should be kept here.
323This is useful when implementing standard functions that may have side
324effects or notable algorithmic implications.
325.It Em RETURN VALUES
326This section documents the
327return values of functions in sections 2, 3, and 9.
328.Pp
329See
330.Sx \&Rv .
331.It Em ENVIRONMENT
332Lists the environment variables used by the utility,
333and explains the syntax and semantics of their values.
334The
335.Xr environ 7
336manual provides examples of typical content and formatting.
337.Pp
338See
339.Sx \&Ev .
340.It Em FILES
341Documents files used.
342It's helpful to document both the file name and a short description of how
343the file is used (created, modified, etc.).
344.Pp
345See
346.Sx \&Pa .
347.It Em EXIT STATUS
348This section documents the
349command exit status for section 1, 6, and 8 utilities.
350Historically, this information was described in
351.Em DIAGNOSTICS ,
352a practise that is now discouraged.
353.Pp
354See
355.Sx \&Ex .
356.It Em EXAMPLES
357Example usages.
358This often contains snippets of well-formed, well-tested invocations.
359Make sure that examples work properly!
360.It Em DIAGNOSTICS
361Documents error conditions.
362This is most useful in section 4 manuals.
363Historically, this section was used in place of
364.Em EXIT STATUS
365for manuals in sections 1, 6, and 8; however, this practise is
366discouraged.
367.Pp
368See
369.Sx \&Bl
370.Fl diag .
371.It Em ERRORS
372Documents error handling in sections 2, 3, and 9.
373.Pp
374See
375.Sx \&Er .
376.It Em SEE ALSO
377References other manuals with related topics.
378This section should exist for most manuals.
379Cross-references should conventionally be ordered first by section, then
380alphabetically.
381.Pp
382References to other documentation concerning the topic of the manual page,
383for example authoritative books or journal articles, may also be
384provided in this section.
385.Pp
386See
387.Sx \&Rs
388and
389.Sx \&Xr .
390.It Em STANDARDS
391References any standards implemented or used.
392If not adhering to any standards, the
393.Em HISTORY
394section should be used instead.
395.Pp
396See
397.Sx \&St .
398.It Em HISTORY
399A brief history of the subject, including where it was first implemented,
400and when it was ported to or reimplemented for the operating system at hand.
401.It Em AUTHORS
402Credits to the person or persons who wrote the code and/or documentation.
403Authors should generally be noted by both name and email address.
404.Pp
405See
406.Sx \&An .
407.It Em CAVEATS
408Common misuses and misunderstandings should be explained
409in this section.
410.It Em BUGS
411Known bugs, limitations, and work-arounds should be described
412in this section.
413.It Em SECURITY CONSIDERATIONS
414Documents any security precautions that operators should consider.
415.El
416.Sh MACRO OVERVIEW
417This overview is sorted such that macros of similar purpose are listed
418together, to help find the best macro for any given purpose.
419Deprecated macros are not included in the overview, but can be found below
420in the alphabetical
421.Sx MACRO REFERENCE .
422.Ss Document preamble and NAME section macros
423.Bl -column "Brq, Bro, Brc" description
424.It Sx \&Dd Ta document date: Cm $\&Mdocdate$ | Ar month day , year
425.It Sx \&Dt Ta document title: Ar TITLE section Op Ar volume | arch
426.It Sx \&Os Ta operating system version: Op Ar system Op Ar version
427.It Sx \&Nm Ta document name (one argument)
428.It Sx \&Nd Ta document description (one line)
429.El
430.Ss Sections and cross references
431.Bl -column "Brq, Bro, Brc" description
432.It Sx \&Sh Ta section header (one line)
433.It Sx \&Ss Ta subsection header (one line)
434.It Sx \&Sx Ta internal cross reference to a section or subsection
435.It Sx \&Xr Ta cross reference to another manual page: Ar name section
436.It Sx \&Pp , \&Lp Ta start a text paragraph (no arguments)
437.El
438.Ss Displays and lists
439.Bl -column "Brq, Bro, Brc" description
440.It Sx \&Bd , \&Ed Ta display block:
441.Fl Ar type
442.Op Fl offset Ar width
443.Op Fl compact
444.It Sx \&D1 Ta indented display (one line)
445.It Sx \&Dl Ta indented literal display (one line)
446.It Sx \&Bl , \&El Ta list block:
447.Fl Ar type
448.Op Fl width Ar val
449.Op Fl offset Ar val
450.Op Fl compact
451.It Sx \&It Ta list item (syntax depends on Fl Ar type )
452.It Sx \&Ta Ta table cell separator in Sx \&Bl Fl column No lists
453.It Sx \&Rs , \&%* , \&Re Ta bibliographic block (references)
454.El
455.Ss Spacing control
456.Bl -column "Brq, Bro, Brc" description
457.It Sx \&Pf Ta prefix, no following horizontal space (one argument)
458.It Sx \&Ns Ta roman font, no preceding horizontal space (no arguments)
459.It Sx \&Ap Ta apostrophe without surrounding whitespace (no arguments)
460.It Sx \&Sm Ta switch horizontal spacing mode: Cm on | off
461.It Sx \&Bk , \&Ek Ta keep block: Fl words
462.It Sx \&br Ta force output line break in text mode (no arguments)
463.It Sx \&sp Ta force vertical space: Op Ar height
464.El
465.Ss Semantic markup for command line utilities:
466.Bl -column "Brq, Bro, Brc" description
467.It Sx \&Nm Ta start a SYNOPSIS block with the name of a utility
468.It Sx \&Fl Ta command line options (flags) (>=0 arguments)
469.It Sx \&Cm Ta command modifier (>0 arguments)
470.It Sx \&Ar Ta command arguments (>=0 arguments)
471.It Sx \&Op , \&Oo , \&Oc Ta optional syntax elements (enclosure)
472.It Sx \&Ic Ta internal or interactive command (>0 arguments)
473.It Sx \&Ev Ta environmental variable (>0 arguments)
474.It Sx \&Pa Ta file system path (>=0 arguments)
475.El
476.Ss Semantic markup for function libraries:
477.Bl -column "Brq, Bro, Brc" description
478.It Sx \&Lb Ta function library (one argument)
479.It Sx \&In Ta include file (one argument)
480.It Sx \&Ft Ta function type (>0 arguments)
481.It Sx \&Fo , \&Fc Ta function block: Ar funcname
482.It Sx \&Fn Ta function name:
483.Op Ar functype
484.Ar funcname
485.Oo
486.Op Ar argtype
487.Ar argname
488.Oc
489.It Sx \&Fa Ta function argument (>0 arguments)
490.It Sx \&Vt Ta variable type (>0 arguments)
491.It Sx \&Va Ta variable name (>0 arguments)
492.It Sx \&Dv Ta defined variable or preprocessor constant (>0 arguments)
493.It Sx \&Er Ta error constant (>0 arguments)
494.It Sx \&Ev Ta environmental variable (>0 arguments)
495.El
496.Ss Various semantic markup:
497.Bl -column "Brq, Bro, Brc" description
498.It Sx \&An Ta author name (>0 arguments)
499.It Sx \&Lk Ta hyperlink: Ar uri Op Ar name
500.It Sx \&Mt Ta Do mailto Dc hyperlink: Ar address
501.It Sx \&Cd Ta kernel configuration declaration (>0 arguments)
502.It Sx \&Ad Ta memory address (>0 arguments)
503.It Sx \&Ms Ta mathematical symbol (>0 arguments)
504.It Sx \&Tn Ta tradename (>0 arguments)
505.El
506.Ss Physical markup
507.Bl -column "Brq, Bro, Brc" description
508.It Sx \&Em Ta italic font or underline (emphasis) (>0 arguments)
509.It Sx \&Sy Ta boldface font (symbolic) (>0 arguments)
510.It Sx \&Li Ta typewriter font (literal) (>0 arguments)
511.It Sx \&No Ta return to roman font (normal) (no arguments)
512.It Sx \&Bf , \&Ef Ta font block:
513.Op Fl Ar type | Cm \&Em | \&Li | \&Sy
514.El
515.Ss Physical enclosures
516.Bl -column "Brq, Bro, Brc" description
517.It Sx \&Dq , \&Do , \&Dc Ta enclose in typographic double quotes: Dq text
518.It Sx \&Qq , \&Qo , \&Qc Ta enclose in typewriter double quotes: Qq text
519.It Sx \&Sq , \&So , \&Sc Ta enclose in single quotes: Sq text
520.It Sx \&Ql Ta single-quoted literal text: Ql text
521.It Sx \&Pq , \&Po , \&Pc Ta enclose in parentheses: Pq text
522.It Sx \&Bq , \&Bo , \&Bc Ta enclose in square brackets: Bq text
523.It Sx \&Brq , \&Bro , \&Brc Ta enclose in curly braces: Brq text
524.It Sx \&Aq , \&Ao , \&Ac Ta enclose in angle brackets: Aq text
525.It Sx \&Eo , \&Ec Ta generic enclosure
526.El
527.Ss Text production
528.Bl -column "Brq, Bro, Brc" description
529.It Sx \&Ex Fl std Ta standard command exit values: Op Ar utility ...
530.It Sx \&Rv Fl std Ta standard function return values: Op Ar function ...
531.It Sx \&St Ta reference to a standards document (one argument)
532.It Sx \&Ux Ta Ux
533.It Sx \&At Ta At
534.It Sx \&Bx Ta Bx
535.It Sx \&Bsx Ta Bsx
536.It Sx \&Nx Ta Nx
537.It Sx \&Fx Ta Fx
538.It Sx \&Ox Ta Ox
539.It Sx \&Dx Ta Dx
540.El
541.Sh MACRO REFERENCE
542This section is a canonical reference of all macros, arranged
543alphabetically.
544For the scoping of individual macros, see
545.Sx MACRO SYNTAX .
546.Ss \&%A
547Author name of an
548.Sx \&Rs
549block.
550Multiple authors should each be accorded their own
551.Sx \%%A
552line.
553Author names should be ordered with full or abbreviated forename(s)
554first, then full surname.
555.Ss \&%B
556Book title of an
557.Sx \&Rs
558block.
559This macro may also be used in a non-bibliographic context when
560referring to book titles.
561.Ss \&%C
562Publication city or location of an
563.Sx \&Rs
564block.
565.Ss \&%D
566Publication date of an
567.Sx \&Rs
568block.
569Recommended formats of arguments are
570.Ar month day , year
571or just
572.Ar year .
573.Ss \&%I
574Publisher or issuer name of an
575.Sx \&Rs
576block.
577.Ss \&%J
578Journal name of an
579.Sx \&Rs
580block.
581.Ss \&%N
582Issue number (usually for journals) of an
583.Sx \&Rs
584block.
585.Ss \&%O
586Optional information of an
587.Sx \&Rs
588block.
589.Ss \&%P
590Book or journal page number of an
591.Sx \&Rs
592block.
593.Ss \&%Q
594Institutional author (school, government, etc.) of an
595.Sx \&Rs
596block.
597Multiple institutional authors should each be accorded their own
598.Sx \&%Q
599line.
600.Ss \&%R
601Technical report name of an
602.Sx \&Rs
603block.
604.Ss \&%T
605Article title of an
606.Sx \&Rs
607block.
608This macro may also be used in a non-bibliographical context when
609referring to article titles.
610.Ss \&%U
611URI of reference document.
612.Ss \&%V
613Volume number of an
614.Sx \&Rs
615block.
616.Ss \&Ac
617Close an
618.Sx \&Ao
619block.
620Does not have any tail arguments.
621.Ss \&Ad
622Memory address.
623Do not use this for postal addresses.
624.Pp
625Examples:
626.Dl \&.Ad [0,$]
627.Dl \&.Ad 0x00000000
628.Ss \&An
629Author name.
630Can be used both for the authors of the program, function, or driver
631documented in the manual, or for the authors of the manual itself.
632Requires either the name of an author or one of the following arguments:
633.Pp
634.Bl -tag -width "-nosplitX" -offset indent -compact
635.It Fl split
636Start a new output line before each subsequent invocation of
637.Sx \&An .
638.It Fl nosplit
639The opposite of
640.Fl split .
641.El
642.Pp
643The default is
644.Fl nosplit .
645The effect of selecting either of the
646.Fl split
647modes ends at the beginning of the
648.Em AUTHORS
649section.
650In the
651.Em AUTHORS
652section, the default is
653.Fl nosplit
654for the first author listing and
655.Fl split
656for all other author listings.
657.Pp
658Examples:
659.Dl \&.An -nosplit
660.Dl \&.An Kristaps Dzonsons \&Aq kristaps@bsd.lv
661.Ss \&Ao
662Begin a block enclosed by angle brackets.
663Does not have any head arguments.
664.Pp
665Examples:
666.Dl \&.Fl -key= \&Ns \&Ao \&Ar val \&Ac
667.Pp
668See also
669.Sx \&Aq .
670.Ss \&Ap
671Inserts an apostrophe without any surrounding whitespace.
672This is generally used as a grammatical device when referring to the verb
673form of a function.
674.Pp
675Examples:
676.Dl \&.Fn execve \&Ap d
677.Ss \&Aq
678Encloses its arguments in angle brackets.
679.Pp
680Examples:
681.Dl \&.Fl -key= \&Ns \&Aq \&Ar val
682.Pp
683.Em Remarks :
684this macro is often abused for rendering URIs, which should instead use
685.Sx \&Lk
686or
687.Sx \&Mt ,
688or to note pre-processor
689.Dq Li #include
690statements, which should use
691.Sx \&In .
692.Pp
693See also
694.Sx \&Ao .
695.Ss \&Ar
696Command arguments.
697If an argument is not provided, the string
698.Dq file ...\&
699is used as a default.
700.Pp
701Examples:
702.Dl ".Fl o Ar file"
703.Dl ".Ar"
704.Dl ".Ar arg1 , arg2 ."
705.Pp
706The arguments to the
707.Sx \&Ar
708macro are names and placeholders for command arguments;
709for fixed strings to be passed verbatim as arguments, use
710.Sx \&Fl
711or
712.Sx \&Cm .
713.Ss \&At
714Formats an AT&T version.
715Accepts one optional argument:
716.Pp
717.Bl -tag -width "v[1-7] | 32vX" -offset indent -compact
718.It Cm v[1-7] | 32v
719A version of
720.At .
721.It Cm III
722.At III .
723.It Cm V[.[1-4]]?
724A version of
725.At V .
726.El
727.Pp
728Note that these arguments do not begin with a hyphen.
729.Pp
730Examples:
731.Dl \&.At
732.Dl \&.At III
733.Dl \&.At V.1
734.Pp
735See also
736.Sx \&Bsx ,
737.Sx \&Bx ,
738.Sx \&Dx ,
739.Sx \&Fx ,
740.Sx \&Nx ,
741.Sx \&Ox ,
742and
743.Sx \&Ux .
744.Ss \&Bc
745Close a
746.Sx \&Bo
747block.
748Does not have any tail arguments.
749.Ss \&Bd
750Begin a display block.
751Its syntax is as follows:
752.Bd -ragged -offset indent
753.Pf \. Sx \&Bd
754.Fl Ns Ar type
755.Op Fl offset Ar width
756.Op Fl compact
757.Ed
758.Pp
759Display blocks are used to select a different indentation and
760justification than the one used by the surrounding text.
761They may contain both macro lines and text lines.
762By default, a display block is preceded by a vertical space.
763.Pp
764The
765.Ar type
766must be one of the following:
767.Bl -tag -width 13n -offset indent
768.It Fl centered
769Produce one output line from each input line, and centre-justify each line.
770Using this display type is not recommended; many
771.Nm
772implementations render it poorly.
773.It Fl filled
774Change the positions of line breaks to fill each line, and left- and
775right-justify the resulting block.
776.It Fl literal
777Produce one output line from each input line,
778and do not justify the block at all.
779Preserve white space as it appears in the input.
780Always use a constant-width font.
781Use this for displaying source code.
782.It Fl ragged
783Change the positions of line breaks to fill each line, and left-justify
784the resulting block.
785.It Fl unfilled
786The same as
787.Fl literal ,
788but using the same font as for normal text, which is a variable width font
789if supported by the output device.
790.El
791.Pp
792The
793.Ar type
794must be provided first.
795Additional arguments may follow:
796.Bl -tag -width 13n -offset indent
797.It Fl offset Ar width
798Indent the display by the
799.Ar width ,
800which may be one of the following:
801.Bl -item
802.It
803One of the pre-defined strings
804.Cm indent ,
805the width of a standard indentation (six constant width characters);
806.Cm indent-two ,
807twice
808.Cm indent ;
809.Cm left ,
810which has no effect;
811.Cm right ,
812which justifies to the right margin; or
813.Cm center ,
814which aligns around an imagined centre axis.
815.It
816A macro invocation, which selects a predefined width
817associated with that macro.
818The most popular is the imaginary macro
819.Ar \&Ds ,
820which resolves to
821.Sy 6n .
822.It
823A scaling width as described in
824.Xr roff 7 .
825.It
826An arbitrary string, which indents by the length of this string.
827.El
828.Pp
829When the argument is missing,
830.Fl offset
831is ignored.
832.It Fl compact
833Do not assert vertical space before the display.
834.El
835.Pp
836Examples:
837.Bd -literal -offset indent
838\&.Bd \-literal \-offset indent \-compact
839   Hello       world.
840\&.Ed
841.Ed
842.Pp
843See also
844.Sx \&D1
845and
846.Sx \&Dl .
847.Ss \&Bf
848Change the font mode for a scoped block of text.
849Its syntax is as follows:
850.Bd -ragged -offset indent
851.Pf \. Sx \&Bf
852.Oo
853.Fl emphasis | literal | symbolic |
854.Cm \&Em | \&Li | \&Sy
855.Oc
856.Ed
857.Pp
858The
859.Fl emphasis
860and
861.Cm \&Em
862argument are equivalent, as are
863.Fl symbolic
864and
865.Cm \&Sy ,
866and
867.Fl literal
868and
869.Cm \&Li .
870Without an argument, this macro does nothing.
871The font mode continues until broken by a new font mode in a nested
872scope or
873.Sx \&Ef
874is encountered.
875.Pp
876See also
877.Sx \&Li ,
878.Sx \&Ef ,
879.Sx \&Em ,
880and
881.Sx \&Sy .
882.Ss \&Bk
883For each macro, keep its output together on the same output line,
884until the end of the macro or the end of the input line is reached,
885whichever comes first.
886Line breaks in text lines are unaffected.
887The syntax is as follows:
888.Pp
889.D1 Pf \. Sx \&Bk Fl words
890.Pp
891The
892.Fl words
893argument is required; additional arguments are ignored.
894.Pp
895The following example will not break within each
896.Sx \&Op
897macro line:
898.Bd -literal -offset indent
899\&.Bk \-words
900\&.Op Fl f Ar flags
901\&.Op Fl o Ar output
902\&.Ek
903.Ed
904.Pp
905Be careful in using over-long lines within a keep block!
906Doing so will clobber the right margin.
907.Ss \&Bl
908Begin a list.
909Lists consist of items specified using the
910.Sx \&It
911macro, containing a head or a body or both.
912The list syntax is as follows:
913.Bd -ragged -offset indent
914.Pf \. Sx \&Bl
915.Fl Ns Ar type
916.Op Fl width Ar val
917.Op Fl offset Ar val
918.Op Fl compact
919.Op HEAD ...
920.Ed
921.Pp
922The list
923.Ar type
924is mandatory and must be specified first.
925The
926.Fl width
927and
928.Fl offset
929arguments accept scaling widths as described in
930.Xr roff 7
931or use the length of the given string.
932The
933.Fl offset
934is a global indentation for the whole list, affecting both item heads
935and bodies.
936For those list types supporting it, the
937.Fl width
938argument requests an additional indentation of item bodies,
939to be added to the
940.Fl offset .
941Unless the
942.Fl compact
943argument is specified, list entries are separated by vertical space.
944.Pp
945A list must specify one of the following list types:
946.Bl -tag -width 12n -offset indent
947.It Fl bullet
948No item heads can be specified, but a bullet will be printed at the head
949of each item.
950Item bodies start on the same output line as the bullet
951and are indented according to the
952.Fl width
953argument.
954.It Fl column
955A columnated list.
956The
957.Fl width
958argument has no effect; instead, each argument specifies the width
959of one column, using either the scaling width syntax described in
960.Xr roff 7
961or the string length of the argument.
962If the first line of the body of a
963.Fl column
964list is not an
965.Sx \&It
966macro line,
967.Sx \&It
968contexts spanning one input line each are implied until an
969.Sx \&It
970macro line is encountered, at which point items start being interpreted as
971described in the
972.Sx \&It
973documentation.
974.It Fl dash
975Like
976.Fl bullet ,
977except that dashes are used in place of bullets.
978.It Fl diag
979Like
980.Fl inset ,
981except that item heads are not parsed for macro invocations.
982Most often used in the
983.Em DIAGNOSTICS
984section with error constants in the item heads.
985.It Fl enum
986A numbered list.
987No item heads can be specified.
988Formatted like
989.Fl bullet ,
990except that cardinal numbers are used in place of bullets,
991starting at 1.
992.It Fl hang
993Like
994.Fl tag ,
995except that the first lines of item bodies are not indented, but follow
996the item heads like in
997.Fl inset
998lists.
999.It Fl hyphen
1000Synonym for
1001.Fl dash .
1002.It Fl inset
1003Item bodies follow items heads on the same line, using normal inter-word
1004spacing.
1005Bodies are not indented, and the
1006.Fl width
1007argument is ignored.
1008.It Fl item
1009No item heads can be specified, and none are printed.
1010Bodies are not indented, and the
1011.Fl width
1012argument is ignored.
1013.It Fl ohang
1014Item bodies start on the line following item heads and are not indented.
1015The
1016.Fl width
1017argument is ignored.
1018.It Fl tag
1019Item bodies are indented according to the
1020.Fl width
1021argument.
1022When an item head fits inside the indentation, the item body follows
1023this head on the same output line.
1024Otherwise, the body starts on the output line following the head.
1025.El
1026.Pp
1027Lists may be nested within lists and displays.
1028Nesting of
1029.Fl column
1030and
1031.Fl enum
1032lists may not be portable.
1033.Pp
1034See also
1035.Sx \&El
1036and
1037.Sx \&It .
1038.Ss \&Bo
1039Begin a block enclosed by square brackets.
1040Does not have any head arguments.
1041.Pp
1042Examples:
1043.Bd -literal -offset indent -compact
1044\&.Bo 1 ,
1045\&.Dv BUFSIZ \&Bc
1046.Ed
1047.Pp
1048See also
1049.Sx \&Bq .
1050.Ss \&Bq
1051Encloses its arguments in square brackets.
1052.Pp
1053Examples:
1054.Dl \&.Bq 1 , \&Dv BUFSIZ
1055.Pp
1056.Em Remarks :
1057this macro is sometimes abused to emulate optional arguments for
1058commands; the correct macros to use for this purpose are
1059.Sx \&Op ,
1060.Sx \&Oo ,
1061and
1062.Sx \&Oc .
1063.Pp
1064See also
1065.Sx \&Bo .
1066.Ss \&Brc
1067Close a
1068.Sx \&Bro
1069block.
1070Does not have any tail arguments.
1071.Ss \&Bro
1072Begin a block enclosed by curly braces.
1073Does not have any head arguments.
1074.Pp
1075Examples:
1076.Bd -literal -offset indent -compact
1077\&.Bro 1 , ... ,
1078\&.Va n \&Brc
1079.Ed
1080.Pp
1081See also
1082.Sx \&Brq .
1083.Ss \&Brq
1084Encloses its arguments in curly braces.
1085.Pp
1086Examples:
1087.Dl \&.Brq 1 , ... , \&Va n
1088.Pp
1089See also
1090.Sx \&Bro .
1091.Ss \&Bsx
1092Format the BSD/OS version provided as an argument, or a default value if
1093no argument is provided.
1094.Pp
1095Examples:
1096.Dl \&.Bsx 1.0
1097.Dl \&.Bsx
1098.Pp
1099See also
1100.Sx \&At ,
1101.Sx \&Bx ,
1102.Sx \&Dx ,
1103.Sx \&Fx ,
1104.Sx \&Nx ,
1105.Sx \&Ox ,
1106and
1107.Sx \&Ux .
1108.Ss \&Bt
1109Prints
1110.Dq is currently in beta test.
1111.Ss \&Bx
1112Format the BSD version provided as an argument, or a default value if no
1113argument is provided.
1114.Pp
1115Examples:
1116.Dl \&.Bx 4.3 Tahoe
1117.Dl \&.Bx 4.4
1118.Dl \&.Bx
1119.Pp
1120See also
1121.Sx \&At ,
1122.Sx \&Bsx ,
1123.Sx \&Dx ,
1124.Sx \&Fx ,
1125.Sx \&Nx ,
1126.Sx \&Ox ,
1127and
1128.Sx \&Ux .
1129.Ss \&Cd
1130Kernel configuration declaration.
1131This denotes strings accepted by
1132.Xr config 8 .
1133It is most often used in section 4 manual pages.
1134.Pp
1135Examples:
1136.Dl \&.Cd device le0 at scode?
1137.Pp
1138.Em Remarks :
1139this macro is commonly abused by using quoted literals to retain
1140whitespace and align consecutive
1141.Sx \&Cd
1142declarations.
1143This practise is discouraged.
1144.Ss \&Cm
1145Command modifiers.
1146Typically used for fixed strings passed as arguments, unless
1147.Sx \&Fl
1148is more appropriate.
1149Also useful when specifying configuration options or keys.
1150.Pp
1151Examples:
1152.Dl ".Nm mt Fl f Ar device Cm rewind"
1153.Dl ".Nm ps Fl o Cm pid , Ns Cm command"
1154.Dl ".Nm dd Cm if= Ns Ar file1 Cm of= Ns Ar file2"
1155.Dl ".Cm IdentityFile Pa ~/.ssh/id_rsa"
1156.Dl ".Cm LogLevel Dv DEBUG"
1157.Ss \&D1
1158One-line indented display.
1159This is formatted by the default rules and is useful for simple indented
1160statements.
1161It is followed by a newline.
1162.Pp
1163Examples:
1164.Dl \&.D1 \&Fl abcdefgh
1165.Pp
1166See also
1167.Sx \&Bd
1168and
1169.Sx \&Dl .
1170.Ss \&Db
1171Switch debugging mode.
1172Its syntax is as follows:
1173.Pp
1174.D1 Pf \. Sx \&Db Cm on | off
1175.Pp
1176This macro is ignored by
1177.Xr mandoc 1 .
1178.Ss \&Dc
1179Close a
1180.Sx \&Do
1181block.
1182Does not have any tail arguments.
1183.Ss \&Dd
1184Document date.
1185This is the mandatory first macro of any
1186.Nm
1187manual.
1188Its syntax is as follows:
1189.Pp
1190.D1 Pf \. Sx \&Dd Ar month day , year
1191.Pp
1192The
1193.Ar month
1194is the full English month name, the
1195.Ar day
1196is an optionally zero-padded numeral, and the
1197.Ar year
1198is the full four-digit year.
1199.Pp
1200Other arguments are not portable; the
1201.Xr mandoc 1
1202utility handles them as follows:
1203.Bl -dash -offset 3n -compact
1204.It
1205To have the date automatically filled in by the
1206.Ox
1207version of
1208.Xr cvs 1 ,
1209the special string
1210.Dq $\&Mdocdate$
1211can be given as an argument.
1212.It
1213A few alternative date formats are accepted as well
1214and converted to the standard form.
1215.It
1216If a date string cannot be parsed, it is used verbatim.
1217.It
1218If no date string is given, the current date is used.
1219.El
1220.Pp
1221Examples:
1222.Dl \&.Dd $\&Mdocdate$
1223.Dl \&.Dd $\&Mdocdate: July 21 2007$
1224.Dl \&.Dd July 21, 2007
1225.Pp
1226See also
1227.Sx \&Dt
1228and
1229.Sx \&Os .
1230.Ss \&Dl
1231One-line intended display.
1232This is formatted as literal text and is useful for commands and
1233invocations.
1234It is followed by a newline.
1235.Pp
1236Examples:
1237.Dl \&.Dl % mandoc mdoc.7 \e(ba less
1238.Pp
1239See also
1240.Sx \&Bd
1241and
1242.Sx \&D1 .
1243.Ss \&Do
1244Begin a block enclosed by double quotes.
1245Does not have any head arguments.
1246.Pp
1247Examples:
1248.Bd -literal -offset indent -compact
1249\&.Do
1250April is the cruellest month
1251\&.Dc
1252\e(em T.S. Eliot
1253.Ed
1254.Pp
1255See also
1256.Sx \&Dq .
1257.Ss \&Dq
1258Encloses its arguments in
1259.Dq typographic
1260double-quotes.
1261.Pp
1262Examples:
1263.Bd -literal -offset indent -compact
1264\&.Dq April is the cruellest month
1265\e(em T.S. Eliot
1266.Ed
1267.Pp
1268See also
1269.Sx \&Qq ,
1270.Sx \&Sq ,
1271and
1272.Sx \&Do .
1273.Ss \&Dt
1274Document title.
1275This is the mandatory second macro of any
1276.Nm
1277file.
1278Its syntax is as follows:
1279.Bd -ragged -offset indent
1280.Pf \. Sx \&Dt
1281.Oo
1282.Ar title
1283.Oo
1284.Ar section
1285.Op Ar volume
1286.Op Ar arch
1287.Oc
1288.Oc
1289.Ed
1290.Pp
1291Its arguments are as follows:
1292.Bl -tag -width Ds -offset Ds
1293.It Ar title
1294The document's title (name), defaulting to
1295.Dq UNKNOWN
1296if unspecified.
1297It should be capitalised.
1298.It Ar section
1299The manual section.
1300This may be one of
1301.Ar 1
1302.Pq utilities ,
1303.Ar 2
1304.Pq system calls ,
1305.Ar 3
1306.Pq libraries ,
1307.Ar 3p
1308.Pq Perl libraries ,
1309.Ar 4
1310.Pq devices ,
1311.Ar 5
1312.Pq file formats ,
1313.Ar 6
1314.Pq games ,
1315.Ar 7
1316.Pq miscellaneous ,
1317.Ar 8
1318.Pq system utilities ,
1319.Ar 9
1320.Pq kernel functions ,
1321.Ar X11
1322.Pq X Window System ,
1323.Ar X11R6
1324.Pq X Window System ,
1325.Ar unass
1326.Pq unassociated ,
1327.Ar local
1328.Pq local system ,
1329.Ar draft
1330.Pq draft manual ,
1331or
1332.Ar paper
1333.Pq paper .
1334It should correspond to the manual's filename suffix and defaults to
1335.Dq 1
1336if unspecified.
1337.It Ar volume
1338This overrides the volume inferred from
1339.Ar section .
1340This field is optional, and if specified, must be one of
1341.Ar USD
1342.Pq users' supplementary documents ,
1343.Ar PS1
1344.Pq programmers' supplementary documents ,
1345.Ar AMD
1346.Pq administrators' supplementary documents ,
1347.Ar SMM
1348.Pq system managers' manuals ,
1349.Ar URM
1350.Pq users' reference manuals ,
1351.Ar PRM
1352.Pq programmers' reference manuals ,
1353.Ar KM
1354.Pq kernel manuals ,
1355.Ar IND
1356.Pq master index ,
1357.Ar MMI
1358.Pq master index ,
1359.Ar LOCAL
1360.Pq local manuals ,
1361.Ar LOC
1362.Pq local manuals ,
1363or
1364.Ar CON
1365.Pq contributed manuals .
1366.It Ar arch
1367This specifies the machine architecture a manual page applies to,
1368where relevant.
1369For
1370.Ox ,
1371the following are valid architectures:
1372.Cm alpha ,
1373.Cm amd64 ,
1374.Cm armish ,
1375.Cm aviion ,
1376.Cm beagle ,
1377.Cm hp300 ,
1378.Cm hppa ,
1379.Cm hppa64 ,
1380.Cm i386 ,
1381.Cm ia64 ,
1382.Cm landisk ,
1383.Cm loongson ,
1384.Cm luna88k ,
1385.Cm macppc ,
1386.Cm mips64 ,
1387.Cm mvme68k ,
1388.Cm mvme88k ,
1389.Cm palm ,
1390.Cm sgi ,
1391.Cm socppc ,
1392.Cm solbourne ,
1393.Cm sparc ,
1394.Cm sparc64 ,
1395.Cm vax ,
1396and
1397.Cm zaurus .
1398.El
1399.Pp
1400Examples:
1401.Dl \&.Dt FOO 1
1402.Dl \&.Dt FOO 4 KM
1403.Dl \&.Dt FOO 9 i386
1404.Pp
1405See also
1406.Sx \&Dd
1407and
1408.Sx \&Os .
1409.Ss \&Dv
1410Defined variables such as preprocessor constants, constant symbols,
1411enumeration values, and so on.
1412.Pp
1413Examples:
1414.Dl \&.Dv NULL
1415.Dl \&.Dv BUFSIZ
1416.Dl \&.Dv STDOUT_FILENO
1417.Pp
1418See also
1419.Sx \&Er
1420and
1421.Sx \&Ev
1422for special-purpose constants and
1423.Sx \&Va
1424for variable symbols.
1425.Ss \&Dx
1426Format the DragonFly BSD version provided as an argument, or a default
1427value if no argument is provided.
1428.Pp
1429Examples:
1430.Dl \&.Dx 2.4.1
1431.Dl \&.Dx
1432.Pp
1433See also
1434.Sx \&At ,
1435.Sx \&Bsx ,
1436.Sx \&Bx ,
1437.Sx \&Fx ,
1438.Sx \&Nx ,
1439.Sx \&Ox ,
1440and
1441.Sx \&Ux .
1442.Ss \&Ec
1443Close a scope started by
1444.Sx \&Eo .
1445Its syntax is as follows:
1446.Pp
1447.D1 Pf \. Sx \&Ec Op Ar TERM
1448.Pp
1449The
1450.Ar TERM
1451argument is used as the enclosure tail, for example, specifying \e(rq
1452will emulate
1453.Sx \&Dc .
1454.Ss \&Ed
1455End a display context started by
1456.Sx \&Bd .
1457.Ss \&Ef
1458End a font mode context started by
1459.Sx \&Bf .
1460.Ss \&Ek
1461End a keep context started by
1462.Sx \&Bk .
1463.Ss \&El
1464End a list context started by
1465.Sx \&Bl .
1466.Pp
1467See also
1468.Sx \&Bl
1469and
1470.Sx \&It .
1471.Ss \&Em
1472Denotes text that should be
1473.Em emphasised .
1474Note that this is a presentation term and should not be used for
1475stylistically decorating technical terms.
1476Depending on the output device, this is usually represented
1477using an italic font or underlined characters.
1478.Pp
1479Examples:
1480.Dl \&.Em Warnings!
1481.Dl \&.Em Remarks :
1482.Pp
1483See also
1484.Sx \&Bf ,
1485.Sx \&Li ,
1486.Sx \&No ,
1487and
1488.Sx \&Sy .
1489.Ss \&En
1490This macro is obsolete and not implemented in
1491.Xr mandoc 1 .
1492.Ss \&Eo
1493An arbitrary enclosure.
1494Its syntax is as follows:
1495.Pp
1496.D1 Pf \. Sx \&Eo Op Ar TERM
1497.Pp
1498The
1499.Ar TERM
1500argument is used as the enclosure head, for example, specifying \e(lq
1501will emulate
1502.Sx \&Do .
1503.Ss \&Er
1504Error constants for definitions of the
1505.Va errno
1506libc global variable.
1507This is most often used in section 2 and 3 manual pages.
1508.Pp
1509Examples:
1510.Dl \&.Er EPERM
1511.Dl \&.Er ENOENT
1512.Pp
1513See also
1514.Sx \&Dv
1515for general constants.
1516.Ss \&Es
1517This macro is obsolete and not implemented.
1518.Ss \&Ev
1519Environmental variables such as those specified in
1520.Xr environ 7 .
1521.Pp
1522Examples:
1523.Dl \&.Ev DISPLAY
1524.Dl \&.Ev PATH
1525.Pp
1526See also
1527.Sx \&Dv
1528for general constants.
1529.Ss \&Ex
1530Insert a standard sentence regarding command exit values of 0 on success
1531and >0 on failure.
1532This is most often used in section 1, 6, and 8 manual pages.
1533Its syntax is as follows:
1534.Pp
1535.D1 Pf \. Sx \&Ex Fl std Op Ar utility ...
1536.Pp
1537If
1538.Ar utility
1539is not specified, the document's name set by
1540.Sx \&Nm
1541is used.
1542Multiple
1543.Ar utility
1544arguments are treated as separate utilities.
1545.Pp
1546See also
1547.Sx \&Rv .
1548.Ss \&Fa
1549Function argument.
1550Its syntax is as follows:
1551.Bd -ragged -offset indent
1552.Pf \. Sx \&Fa
1553.Op Cm argtype
1554.Cm argname
1555.Ed
1556.Pp
1557This may be invoked for names with or without the corresponding type.
1558It is also used to specify the field name of a structure.
1559Most often, the
1560.Sx \&Fa
1561macro is used in the
1562.Em SYNOPSIS
1563within
1564.Sx \&Fo
1565section when documenting multi-line function prototypes.
1566If invoked with multiple arguments, the arguments are separated by a
1567comma.
1568Furthermore, if the following macro is another
1569.Sx \&Fa ,
1570the last argument will also have a trailing comma.
1571.Pp
1572Examples:
1573.Dl \&.Fa \(dqconst char *p\(dq
1574.Dl \&.Fa \(dqint a\(dq \(dqint b\(dq \(dqint c\(dq
1575.Dl \&.Fa foo
1576.Pp
1577See also
1578.Sx \&Fo .
1579.Ss \&Fc
1580End a function context started by
1581.Sx \&Fo .
1582.Ss \&Fd
1583Historically used to document include files.
1584This usage has been deprecated in favour of
1585.Sx \&In .
1586Do not use this macro.
1587.Pp
1588See also
1589.Sx MANUAL STRUCTURE
1590and
1591.Sx \&In .
1592.Ss \&Fl
1593Command-line flag or option.
1594Used when listing arguments to command-line utilities.
1595Prints a fixed-width hyphen
1596.Sq \-
1597directly followed by each argument.
1598If no arguments are provided, a hyphen is printed followed by a space.
1599If the argument is a macro, a hyphen is prefixed to the subsequent macro
1600output.
1601.Pp
1602Examples:
1603.Dl ".Fl R Op Fl H | L | P"
1604.Dl ".Op Fl 1AaCcdFfgHhikLlmnopqRrSsTtux"
1605.Dl ".Fl type Cm d Fl name Pa CVS"
1606.Dl ".Fl Ar signal_number"
1607.Dl ".Fl o Fl"
1608.Pp
1609See also
1610.Sx \&Cm .
1611.Ss \&Fn
1612A function name.
1613Its syntax is as follows:
1614.Bd -ragged -offset indent
1615.Pf \. Ns Sx \&Fn
1616.Op Ar functype
1617.Ar funcname
1618.Op Oo Ar argtype Oc Ar argname
1619.Ed
1620.Pp
1621Function arguments are surrounded in parenthesis and
1622are delimited by commas.
1623If no arguments are specified, blank parenthesis are output.
1624In the
1625.Em SYNOPSIS
1626section, this macro starts a new output line,
1627and a blank line is automatically inserted between function definitions.
1628.Pp
1629Examples:
1630.Dl \&.Fn \(dqint funcname\(dq \(dqint arg0\(dq \(dqint arg1\(dq
1631.Dl \&.Fn funcname \(dqint arg0\(dq
1632.Dl \&.Fn funcname arg0
1633.Pp
1634.Bd -literal -offset indent -compact
1635\&.Ft functype
1636\&.Fn funcname
1637.Ed
1638.Pp
1639When referring to a function documented in another manual page, use
1640.Sx \&Xr
1641instead.
1642See also
1643.Sx MANUAL STRUCTURE ,
1644.Sx \&Fo ,
1645and
1646.Sx \&Ft .
1647.Ss \&Fo
1648Begin a function block.
1649This is a multi-line version of
1650.Sx \&Fn .
1651Its syntax is as follows:
1652.Pp
1653.D1 Pf \. Sx \&Fo Ar funcname
1654.Pp
1655Invocations usually occur in the following context:
1656.Bd -ragged -offset indent
1657.Pf \. Sx \&Ft Ar functype
1658.br
1659.Pf \. Sx \&Fo Ar funcname
1660.br
1661.Pf \. Sx \&Fa Oo Ar argtype Oc Ar argname
1662.br
1663\&.\.\.
1664.br
1665.Pf \. Sx \&Fc
1666.Ed
1667.Pp
1668A
1669.Sx \&Fo
1670scope is closed by
1671.Sx \&Fc .
1672.Pp
1673See also
1674.Sx MANUAL STRUCTURE ,
1675.Sx \&Fa ,
1676.Sx \&Fc ,
1677and
1678.Sx \&Ft .
1679.Ss \&Fr
1680This macro is obsolete and not implemented in
1681.Xr mandoc 1 .
1682.Pp
1683It was used to show function return values.
1684The syntax was:
1685.Pp
1686.Dl Pf . Sx \&Fr Ar value
1687.Ss \&Ft
1688A function type.
1689Its syntax is as follows:
1690.Pp
1691.D1 Pf \. Sx \&Ft Ar functype
1692.Pp
1693In the
1694.Em SYNOPSIS
1695section, a new output line is started after this macro.
1696.Pp
1697Examples:
1698.Dl \&.Ft int
1699.Bd -literal -offset indent -compact
1700\&.Ft functype
1701\&.Fn funcname
1702.Ed
1703.Pp
1704See also
1705.Sx MANUAL STRUCTURE ,
1706.Sx \&Fn ,
1707and
1708.Sx \&Fo .
1709.Ss \&Fx
1710Format the
1711.Fx
1712version provided as an argument, or a default value
1713if no argument is provided.
1714.Pp
1715Examples:
1716.Dl \&.Fx 7.1
1717.Dl \&.Fx
1718.Pp
1719See also
1720.Sx \&At ,
1721.Sx \&Bsx ,
1722.Sx \&Bx ,
1723.Sx \&Dx ,
1724.Sx \&Nx ,
1725.Sx \&Ox ,
1726and
1727.Sx \&Ux .
1728.Ss \&Hf
1729This macro is not implemented in
1730.Xr mandoc 1 .
1731.Pp
1732It was used to include the contents of a (header) file literally.
1733The syntax was:
1734.Pp
1735.Dl Pf . Sx \&Hf Ar filename
1736.Ss \&Ic
1737Designate an internal or interactive command.
1738This is similar to
1739.Sx \&Cm
1740but used for instructions rather than values.
1741.Pp
1742Examples:
1743.Dl \&.Ic :wq
1744.Dl \&.Ic hash
1745.Dl \&.Ic alias
1746.Pp
1747Note that using
1748.Sx \&Bd Fl literal
1749or
1750.Sx \&D1
1751is preferred for displaying code; the
1752.Sx \&Ic
1753macro is used when referring to specific instructions.
1754.Ss \&In
1755An
1756.Dq include
1757file.
1758When invoked as the first macro on an input line in the
1759.Em SYNOPSIS
1760section, the argument is displayed in angle brackets
1761and preceded by
1762.Dq #include ,
1763and a blank line is inserted in front if there is a preceding
1764function declaration.
1765This is most often used in section 2, 3, and 9 manual pages.
1766.Pp
1767Examples:
1768.Dl \&.In sys/types.h
1769.Pp
1770See also
1771.Sx MANUAL STRUCTURE .
1772.Ss \&It
1773A list item.
1774The syntax of this macro depends on the list type.
1775.Pp
1776Lists
1777of type
1778.Fl hang ,
1779.Fl ohang ,
1780.Fl inset ,
1781and
1782.Fl diag
1783have the following syntax:
1784.Pp
1785.D1 Pf \. Sx \&It Ar args
1786.Pp
1787Lists of type
1788.Fl bullet ,
1789.Fl dash ,
1790.Fl enum ,
1791.Fl hyphen
1792and
1793.Fl item
1794have the following syntax:
1795.Pp
1796.D1 Pf \. Sx \&It
1797.Pp
1798with subsequent lines interpreted within the scope of the
1799.Sx \&It
1800until either a closing
1801.Sx \&El
1802or another
1803.Sx \&It .
1804.Pp
1805The
1806.Fl tag
1807list has the following syntax:
1808.Pp
1809.D1 Pf \. Sx \&It Op Cm args
1810.Pp
1811Subsequent lines are interpreted as with
1812.Fl bullet
1813and family.
1814The line arguments correspond to the list's left-hand side; body
1815arguments correspond to the list's contents.
1816.Pp
1817The
1818.Fl column
1819list is the most complicated.
1820Its syntax is as follows:
1821.Pp
1822.D1 Pf \. Sx \&It Ar cell Op <TAB> Ar cell ...
1823.D1 Pf \. Sx \&It Ar cell Op Sx \&Ta Ar cell ...
1824.Pp
1825The arguments consist of one or more lines of text and macros
1826representing a complete table line.
1827Cells within the line are delimited by tabs or by the special
1828.Sx \&Ta
1829block macro.
1830The tab cell delimiter may only be used within the
1831.Sx \&It
1832line itself; on following lines, only the
1833.Sx \&Ta
1834macro can be used to delimit cells, and
1835.Sx \&Ta
1836is only recognised as a macro when called by other macros,
1837not as the first macro on a line.
1838.Pp
1839Note that quoted strings may span tab-delimited cells on an
1840.Sx \&It
1841line.
1842For example,
1843.Pp
1844.Dl .It \(dqcol1 ; <TAB> col2 ;\(dq \&;
1845.Pp
1846will preserve the semicolon whitespace except for the last.
1847.Pp
1848See also
1849.Sx \&Bl .
1850.Ss \&Lb
1851Specify a library.
1852The syntax is as follows:
1853.Pp
1854.D1 Pf \. Sx \&Lb Ar library
1855.Pp
1856The
1857.Ar library
1858parameter may be a system library, such as
1859.Cm libz
1860or
1861.Cm libpam ,
1862in which case a small library description is printed next to the linker
1863invocation; or a custom library, in which case the library name is
1864printed in quotes.
1865This is most commonly used in the
1866.Em SYNOPSIS
1867section as described in
1868.Sx MANUAL STRUCTURE .
1869.Pp
1870Examples:
1871.Dl \&.Lb libz
1872.Dl \&.Lb mdoc
1873.Ss \&Li
1874Denotes text that should be in a
1875.Li literal
1876font mode.
1877Note that this is a presentation term and should not be used for
1878stylistically decorating technical terms.
1879.Pp
1880On terminal output devices, this is often indistinguishable from
1881normal text.
1882.Pp
1883See also
1884.Sx \&Bf ,
1885.Sx \&Em ,
1886.Sx \&No ,
1887and
1888.Sx \&Sy .
1889.Ss \&Lk
1890Format a hyperlink.
1891Its syntax is as follows:
1892.Pp
1893.D1 Pf \. Sx \&Lk Ar uri Op Ar name
1894.Pp
1895Examples:
1896.Dl \&.Lk http://bsd.lv \(dqThe BSD.lv Project\(dq
1897.Dl \&.Lk http://bsd.lv
1898.Pp
1899See also
1900.Sx \&Mt .
1901.Ss \&Lp
1902Synonym for
1903.Sx \&Pp .
1904.Ss \&Ms
1905Display a mathematical symbol.
1906Its syntax is as follows:
1907.Pp
1908.D1 Pf \. Sx \&Ms Ar symbol
1909.Pp
1910Examples:
1911.Dl \&.Ms sigma
1912.Dl \&.Ms aleph
1913.Ss \&Mt
1914Format a
1915.Dq mailto:
1916hyperlink.
1917Its syntax is as follows:
1918.Pp
1919.D1 Pf \. Sx \&Mt Ar address
1920.Pp
1921Examples:
1922.Dl \&.Mt discuss@manpages.bsd.lv
1923.Ss \&Nd
1924A one line description of the manual's content.
1925This may only be invoked in the
1926.Em SYNOPSIS
1927section subsequent the
1928.Sx \&Nm
1929macro.
1930.Pp
1931Examples:
1932.Dl Pf . Sx \&Nd mdoc language reference
1933.Dl Pf . Sx \&Nd format and display UNIX manuals
1934.Pp
1935The
1936.Sx \&Nd
1937macro technically accepts child macros and terminates with a subsequent
1938.Sx \&Sh
1939invocation.
1940Do not assume this behaviour: some
1941.Xr whatis 1
1942database generators are not smart enough to parse more than the line
1943arguments and will display macros verbatim.
1944.Pp
1945See also
1946.Sx \&Nm .
1947.Ss \&Nm
1948The name of the manual page, or \(em in particular in section 1, 6,
1949and 8 pages \(em of an additional command or feature documented in
1950the manual page.
1951When first invoked, the
1952.Sx \&Nm
1953macro expects a single argument, the name of the manual page.
1954Usually, the first invocation happens in the
1955.Em NAME
1956section of the page.
1957The specified name will be remembered and used whenever the macro is
1958called again without arguments later in the page.
1959The
1960.Sx \&Nm
1961macro uses
1962.Sx Block full-implicit
1963semantics when invoked as the first macro on an input line in the
1964.Em SYNOPSIS
1965section; otherwise, it uses ordinary
1966.Sx In-line
1967semantics.
1968.Pp
1969Examples:
1970.Bd -literal -offset indent
1971\&.Sh SYNOPSIS
1972\&.Nm cat
1973\&.Op Fl benstuv
1974\&.Op Ar
1975.Ed
1976.Pp
1977In the
1978.Em SYNOPSIS
1979of section 2, 3 and 9 manual pages, use the
1980.Sx \&Fn
1981macro rather than
1982.Sx \&Nm
1983to mark up the name of the manual page.
1984.Ss \&No
1985Normal text.
1986Closes the scope of any preceding in-line macro.
1987When used after physical formatting macros like
1988.Sx \&Em
1989or
1990.Sx \&Sy ,
1991switches back to the standard font face and weight.
1992Can also be used to embed plain text strings in macro lines
1993using semantic annotation macros.
1994.Pp
1995Examples:
1996.Dl ".Em italic , Sy bold , No and roman"
1997.Pp
1998.Bd -literal -offset indent -compact
1999\&.Sm off
2000\&.Cm :C No / Ar pattern No / Ar replacement No /
2001\&.Sm on
2002.Ed
2003.Pp
2004See also
2005.Sx \&Em ,
2006.Sx \&Li ,
2007and
2008.Sx \&Sy .
2009.Ss \&Ns
2010Suppress a space between the output of the preceding macro
2011and the following text or macro.
2012Following invocation, input is interpreted as normal text
2013just like after an
2014.Sx \&No
2015macro.
2016.Pp
2017This has no effect when invoked at the start of a macro line.
2018.Pp
2019Examples:
2020.Dl ".Ar name Ns = Ns Ar value"
2021.Dl ".Cm :M Ns Ar pattern"
2022.Dl ".Fl o Ns Ar output"
2023.Pp
2024See also
2025.Sx \&No
2026and
2027.Sx \&Sm .
2028.Ss \&Nx
2029Format the
2030.Nx
2031version provided as an argument, or a default value if
2032no argument is provided.
2033.Pp
2034Examples:
2035.Dl \&.Nx 5.01
2036.Dl \&.Nx
2037.Pp
2038See also
2039.Sx \&At ,
2040.Sx \&Bsx ,
2041.Sx \&Bx ,
2042.Sx \&Dx ,
2043.Sx \&Fx ,
2044.Sx \&Ox ,
2045and
2046.Sx \&Ux .
2047.Ss \&Oc
2048Close multi-line
2049.Sx \&Oo
2050context.
2051.Ss \&Oo
2052Multi-line version of
2053.Sx \&Op .
2054.Pp
2055Examples:
2056.Bd -literal -offset indent -compact
2057\&.Oo
2058\&.Op Fl flag Ns Ar value
2059\&.Oc
2060.Ed
2061.Ss \&Op
2062Optional part of a command line.
2063Prints the argument(s) in brackets.
2064This is most often used in the
2065.Em SYNOPSIS
2066section of section 1 and 8 manual pages.
2067.Pp
2068Examples:
2069.Dl \&.Op \&Fl a \&Ar b
2070.Dl \&.Op \&Ar a | b
2071.Pp
2072See also
2073.Sx \&Oo .
2074.Ss \&Os
2075Document operating system version.
2076This is the mandatory third macro of
2077any
2078.Nm
2079file.
2080Its syntax is as follows:
2081.Pp
2082.D1 Pf \. Sx \&Os Op Ar system Op Ar version
2083.Pp
2084The optional
2085.Ar system
2086parameter specifies the relevant operating system or environment.
2087Left unspecified, it defaults to the local operating system version.
2088This is the suggested form.
2089.Pp
2090Examples:
2091.Dl \&.Os
2092.Dl \&.Os KTH/CSC/TCS
2093.Dl \&.Os BSD 4.3
2094.Pp
2095See also
2096.Sx \&Dd
2097and
2098.Sx \&Dt .
2099.Ss \&Ot
2100This macro is obsolete and not implemented in
2101.Xr mandoc 1 .
2102.Pp
2103Historical
2104.Xr mdoc 7
2105packages described it as
2106.Dq "old function type (FORTRAN)" .
2107.Ss \&Ox
2108Format the
2109.Ox
2110version provided as an argument, or a default value
2111if no argument is provided.
2112.Pp
2113Examples:
2114.Dl \&.Ox 4.5
2115.Dl \&.Ox
2116.Pp
2117See also
2118.Sx \&At ,
2119.Sx \&Bsx ,
2120.Sx \&Bx ,
2121.Sx \&Dx ,
2122.Sx \&Fx ,
2123.Sx \&Nx ,
2124and
2125.Sx \&Ux .
2126.Ss \&Pa
2127An absolute or relative file system path, or a file or directory name.
2128If an argument is not provided, the character
2129.Sq \(ti
2130is used as a default.
2131.Pp
2132Examples:
2133.Dl \&.Pa /usr/bin/mandoc
2134.Dl \&.Pa /usr/share/man/man7/mdoc.7
2135.Pp
2136See also
2137.Sx \&Lk .
2138.Ss \&Pc
2139Close parenthesised context opened by
2140.Sx \&Po .
2141.Ss \&Pf
2142Removes the space between its argument
2143.Pq Dq prefix
2144and the following macro.
2145Its syntax is as follows:
2146.Pp
2147.D1 .Pf Ar prefix macro arguments ...
2148.Pp
2149This is equivalent to:
2150.Pp
2151.D1 .No Ar prefix No \&Ns Ar macro arguments ...
2152.Pp
2153Examples:
2154.Dl ".Pf $ Ar variable_name"
2155.Dl ".Pf 0x Ar hex_digits"
2156.Pp
2157See also
2158.Sx \&Ns
2159and
2160.Sx \&Sm .
2161.Ss \&Po
2162Multi-line version of
2163.Sx \&Pq .
2164.Ss \&Pp
2165Break a paragraph.
2166This will assert vertical space between prior and subsequent macros
2167and/or text.
2168.Pp
2169Paragraph breaks are not needed before or after
2170.Sx \&Sh
2171or
2172.Sx \&Ss
2173macros or before displays
2174.Pq Sx \&Bd
2175or lists
2176.Pq Sx \&Bl
2177unless the
2178.Fl compact
2179flag is given.
2180.Ss \&Pq
2181Parenthesised enclosure.
2182.Pp
2183See also
2184.Sx \&Po .
2185.Ss \&Qc
2186Close quoted context opened by
2187.Sx \&Qo .
2188.Ss \&Ql
2189Format a single-quoted literal.
2190See also
2191.Sx \&Qq
2192and
2193.Sx \&Sq .
2194.Ss \&Qo
2195Multi-line version of
2196.Sx \&Qq .
2197.Ss \&Qq
2198Encloses its arguments in
2199.Qq typewriter
2200double-quotes.
2201Consider using
2202.Sx \&Dq .
2203.Pp
2204See also
2205.Sx \&Dq ,
2206.Sx \&Sq ,
2207and
2208.Sx \&Qo .
2209.Ss \&Re
2210Close an
2211.Sx \&Rs
2212block.
2213Does not have any tail arguments.
2214.Ss \&Rs
2215Begin a bibliographic
2216.Pq Dq reference
2217block.
2218Does not have any head arguments.
2219The block macro may only contain
2220.Sx \&%A ,
2221.Sx \&%B ,
2222.Sx \&%C ,
2223.Sx \&%D ,
2224.Sx \&%I ,
2225.Sx \&%J ,
2226.Sx \&%N ,
2227.Sx \&%O ,
2228.Sx \&%P ,
2229.Sx \&%Q ,
2230.Sx \&%R ,
2231.Sx \&%T ,
2232.Sx \&%U ,
2233and
2234.Sx \&%V
2235child macros (at least one must be specified).
2236.Pp
2237Examples:
2238.Bd -literal -offset indent -compact
2239\&.Rs
2240\&.%A J. E. Hopcroft
2241\&.%A J. D. Ullman
2242\&.%B Introduction to Automata Theory, Languages, and Computation
2243\&.%I Addison-Wesley
2244\&.%C Reading, Massachusettes
2245\&.%D 1979
2246\&.Re
2247.Ed
2248.Pp
2249If an
2250.Sx \&Rs
2251block is used within a SEE ALSO section, a vertical space is asserted
2252before the rendered output, else the block continues on the current
2253line.
2254.Ss \&Rv
2255Insert a standard sentence regarding a function call's return value of 0
2256on success and \-1 on error, with the
2257.Va errno
2258libc global variable set on error.
2259Its syntax is as follows:
2260.Pp
2261.D1 Pf \. Sx \&Rv Fl std Op Ar function ...
2262.Pp
2263If
2264.Ar function
2265is not specified, the document's name set by
2266.Sx \&Nm
2267is used.
2268Multiple
2269.Ar function
2270arguments are treated as separate functions.
2271.Pp
2272See also
2273.Sx \&Ex .
2274.Ss \&Sc
2275Close single-quoted context opened by
2276.Sx \&So .
2277.Ss \&Sh
2278Begin a new section.
2279For a list of conventional manual sections, see
2280.Sx MANUAL STRUCTURE .
2281These sections should be used unless it's absolutely necessary that
2282custom sections be used.
2283.Pp
2284Section names should be unique so that they may be keyed by
2285.Sx \&Sx .
2286Although this macro is parsed, it should not consist of child node or it
2287may not be linked with
2288.Sx \&Sx .
2289.Pp
2290See also
2291.Sx \&Pp ,
2292.Sx \&Ss ,
2293and
2294.Sx \&Sx .
2295.Ss \&Sm
2296Switches the spacing mode for output generated from macros.
2297Its syntax is as follows:
2298.Pp
2299.D1 Pf \. Sx \&Sm Cm on | off
2300.Pp
2301By default, spacing is
2302.Cm on .
2303When switched
2304.Cm off ,
2305no white space is inserted between macro arguments and between the
2306output generated from adjacent macros, but text lines
2307still get normal spacing between words and sentences.
2308.Ss \&So
2309Multi-line version of
2310.Sx \&Sq .
2311.Ss \&Sq
2312Encloses its arguments in
2313.Sq typewriter
2314single-quotes.
2315.Pp
2316See also
2317.Sx \&Dq ,
2318.Sx \&Qq ,
2319and
2320.Sx \&So .
2321.Ss \&Ss
2322Begin a new subsection.
2323Unlike with
2324.Sx \&Sh ,
2325there is no convention for the naming of subsections.
2326Except
2327.Em DESCRIPTION ,
2328the conventional sections described in
2329.Sx MANUAL STRUCTURE
2330rarely have subsections.
2331.Pp
2332Sub-section names should be unique so that they may be keyed by
2333.Sx \&Sx .
2334Although this macro is parsed, it should not consist of child node or it
2335may not be linked with
2336.Sx \&Sx .
2337.Pp
2338See also
2339.Sx \&Pp ,
2340.Sx \&Sh ,
2341and
2342.Sx \&Sx .
2343.Ss \&St
2344Replace an abbreviation for a standard with the full form.
2345The following standards are recognised:
2346.Pp
2347.Bl -tag -width "-p1003.1g-2000X" -compact
2348.It \-p1003.1-88
2349.St -p1003.1-88
2350.It \-p1003.1-90
2351.St -p1003.1-90
2352.It \-p1003.1-96
2353.St -p1003.1-96
2354.It \-p1003.1-2001
2355.St -p1003.1-2001
2356.It \-p1003.1-2004
2357.St -p1003.1-2004
2358.It \-p1003.1-2008
2359.St -p1003.1-2008
2360.It \-p1003.1
2361.St -p1003.1
2362.It \-p1003.1b
2363.St -p1003.1b
2364.It \-p1003.1b-93
2365.St -p1003.1b-93
2366.It \-p1003.1c-95
2367.St -p1003.1c-95
2368.It \-p1003.1g-2000
2369.St -p1003.1g-2000
2370.It \-p1003.1i-95
2371.St -p1003.1i-95
2372.It \-p1003.2-92
2373.St -p1003.2-92
2374.It \-p1003.2a-92
2375.St -p1003.2a-92
2376.It \-p1387.2-95
2377.St -p1387.2-95
2378.It \-p1003.2
2379.St -p1003.2
2380.It \-p1387.2
2381.St -p1387.2
2382.It \-isoC
2383.St -isoC
2384.It \-isoC-90
2385.St -isoC-90
2386.It \-isoC-amd1
2387.St -isoC-amd1
2388.It \-isoC-tcor1
2389.St -isoC-tcor1
2390.It \-isoC-tcor2
2391.St -isoC-tcor2
2392.It \-isoC-99
2393.St -isoC-99
2394.It \-isoC-2011
2395.St -isoC-2011
2396.It \-iso9945-1-90
2397.St -iso9945-1-90
2398.It \-iso9945-1-96
2399.St -iso9945-1-96
2400.It \-iso9945-2-93
2401.St -iso9945-2-93
2402.It \-ansiC
2403.St -ansiC
2404.It \-ansiC-89
2405.St -ansiC-89
2406.It \-ansiC-99
2407.St -ansiC-99
2408.It \-ieee754
2409.St -ieee754
2410.It \-iso8802-3
2411.St -iso8802-3
2412.It \-iso8601
2413.St -iso8601
2414.It \-ieee1275-94
2415.St -ieee1275-94
2416.It \-xpg3
2417.St -xpg3
2418.It \-xpg4
2419.St -xpg4
2420.It \-xpg4.2
2421.St -xpg4.2
2422.It \-xpg4.3
2423.St -xpg4.3
2424.It \-xbd5
2425.St -xbd5
2426.It \-xcu5
2427.St -xcu5
2428.It \-xsh5
2429.St -xsh5
2430.It \-xns5
2431.St -xns5
2432.It \-xns5.2
2433.St -xns5.2
2434.It \-xns5.2d2.0
2435.St -xns5.2d2.0
2436.It \-xcurses4.2
2437.St -xcurses4.2
2438.It \-susv2
2439.St -susv2
2440.It \-susv3
2441.St -susv3
2442.It \-svid4
2443.St -svid4
2444.El
2445.Ss \&Sx
2446Reference a section or subsection in the same manual page.
2447The referenced section or subsection name must be identical to the
2448enclosed argument, including whitespace.
2449.Pp
2450Examples:
2451.Dl \&.Sx MANUAL STRUCTURE
2452.Pp
2453See also
2454.Sx \&Sh
2455and
2456.Sx \&Ss .
2457.Ss \&Sy
2458Format enclosed arguments in symbolic
2459.Pq Dq boldface .
2460Note that this is a presentation term and should not be used for
2461stylistically decorating technical terms.
2462.Pp
2463See also
2464.Sx \&Bf ,
2465.Sx \&Em ,
2466.Sx \&Li ,
2467and
2468.Sx \&No .
2469.Ss \&Ta
2470Table cell separator in
2471.Sx \&Bl Fl column
2472lists; can only be used below
2473.Sx \&It .
2474.Ss \&Tn
2475Format a tradename.
2476.Pp
2477Since this macro is often implemented to use a small caps font,
2478it has historically been used for acronyms (like ASCII) as well.
2479Such usage is not recommended because it would use the same macro
2480sometimes for semantical annotation, sometimes for physical formatting.
2481.Pp
2482Examples:
2483.Dl \&.Tn IBM
2484.Ss \&Ud
2485Prints out
2486.Dq currently under development.
2487.Ss \&Ux
2488Format the UNIX name.
2489Accepts no argument.
2490.Pp
2491Examples:
2492.Dl \&.Ux
2493.Pp
2494See also
2495.Sx \&At ,
2496.Sx \&Bsx ,
2497.Sx \&Bx ,
2498.Sx \&Dx ,
2499.Sx \&Fx ,
2500.Sx \&Nx ,
2501and
2502.Sx \&Ox .
2503.Ss \&Va
2504A variable name.
2505.Pp
2506Examples:
2507.Dl \&.Va foo
2508.Dl \&.Va const char *bar ;
2509.Ss \&Vt
2510A variable type.
2511This is also used for indicating global variables in the
2512.Em SYNOPSIS
2513section, in which case a variable name is also specified.
2514Note that it accepts
2515.Sx Block partial-implicit
2516syntax when invoked as the first macro on an input line in the
2517.Em SYNOPSIS
2518section, else it accepts ordinary
2519.Sx In-line
2520syntax.
2521In the former case, this macro starts a new output line,
2522and a blank line is inserted in front if there is a preceding
2523function definition or include directive.
2524.Pp
2525Note that this should not be confused with
2526.Sx \&Ft ,
2527which is used for function return types.
2528.Pp
2529Examples:
2530.Dl \&.Vt unsigned char
2531.Dl \&.Vt extern const char * const sys_signame[] \&;
2532.Pp
2533See also
2534.Sx MANUAL STRUCTURE
2535and
2536.Sx \&Va .
2537.Ss \&Xc
2538Close a scope opened by
2539.Sx \&Xo .
2540.Ss \&Xo
2541Extend the header of an
2542.Sx \&It
2543macro or the body of a partial-implicit block macro
2544beyond the end of the input line.
2545This macro originally existed to work around the 9-argument limit
2546of historic
2547.Xr roff 7 .
2548.Ss \&Xr
2549Link to another manual
2550.Pq Qq cross-reference .
2551Its syntax is as follows:
2552.Pp
2553.D1 Pf \. Sx \&Xr Ar name section
2554.Pp
2555The
2556.Ar name
2557and
2558.Ar section
2559are the name and section of the linked manual.
2560If
2561.Ar section
2562is followed by non-punctuation, an
2563.Sx \&Ns
2564is inserted into the token stream.
2565This behaviour is for compatibility with
2566GNU troff.
2567.Pp
2568Examples:
2569.Dl \&.Xr mandoc 1
2570.Dl \&.Xr mandoc 1 \&;
2571.Dl \&.Xr mandoc 1 \&Ns s behaviour
2572.Ss \&br
2573Emits a line-break.
2574This macro should not be used; it is implemented for compatibility with
2575historical manuals.
2576.Pp
2577Consider using
2578.Sx \&Pp
2579in the event of natural paragraph breaks.
2580.Ss \&sp
2581Emits vertical space.
2582This macro should not be used; it is implemented for compatibility with
2583historical manuals.
2584Its syntax is as follows:
2585.Pp
2586.D1 Pf \. Sx \&sp Op Ar height
2587.Pp
2588The
2589.Ar height
2590argument is a scaling width as described in
2591.Xr roff 7 .
2592If unspecified,
2593.Sx \&sp
2594asserts a single vertical space.
2595.Sh MACRO SYNTAX
2596The syntax of a macro depends on its classification.
2597In this section,
2598.Sq \-arg
2599refers to macro arguments, which may be followed by zero or more
2600.Sq parm
2601parameters;
2602.Sq \&Yo
2603opens the scope of a macro; and if specified,
2604.Sq \&Yc
2605closes it out.
2606.Pp
2607The
2608.Em Callable
2609column indicates that the macro may also be called by passing its name
2610as an argument to another macro.
2611For example,
2612.Sq \&.Op \&Fl O \&Ar file
2613produces
2614.Sq Op Fl O Ar file .
2615To prevent a macro call and render the macro name literally,
2616escape it by prepending a zero-width space,
2617.Sq \e& .
2618For example,
2619.Sq \&Op \e&Fl O
2620produces
2621.Sq Op \&Fl O .
2622If a macro is not callable but its name appears as an argument
2623to another macro, it is interpreted as opaque text.
2624For example,
2625.Sq \&.Fl \&Sh
2626produces
2627.Sq Fl \&Sh .
2628.Pp
2629The
2630.Em Parsed
2631column indicates whether the macro may call other macros by receiving
2632their names as arguments.
2633If a macro is not parsed but the name of another macro appears
2634as an argument, it is interpreted as opaque text.
2635.Pp
2636The
2637.Em Scope
2638column, if applicable, describes closure rules.
2639.Ss Block full-explicit
2640Multi-line scope closed by an explicit closing macro.
2641All macros contains bodies; only
2642.Sx \&Bf
2643and
2644.Pq optionally
2645.Sx \&Bl
2646contain a head.
2647.Bd -literal -offset indent
2648\&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
2649\(lBbody...\(rB
2650\&.Yc
2651.Ed
2652.Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXX" -offset indent
2653.It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
2654.It Sx \&Bd  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ed
2655.It Sx \&Bf  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ef
2656.It Sx \&Bk  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ek
2657.It Sx \&Bl  Ta    \&No     Ta    \&No     Ta    closed by Sx \&El
2658.It Sx \&Ed  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bd
2659.It Sx \&Ef  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bf
2660.It Sx \&Ek  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bk
2661.It Sx \&El  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bl
2662.El
2663.Ss Block full-implicit
2664Multi-line scope closed by end-of-file or implicitly by another macro.
2665All macros have bodies; some
2666.Po
2667.Sx \&It Fl bullet ,
2668.Fl hyphen ,
2669.Fl dash ,
2670.Fl enum ,
2671.Fl item
2672.Pc
2673don't have heads; only one
2674.Po
2675.Sx \&It
2676in
2677.Sx \&Bl Fl column
2678.Pc
2679has multiple heads.
2680.Bd -literal -offset indent
2681\&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead... \(lBTa head...\(rB\(rB
2682\(lBbody...\(rB
2683.Ed
2684.Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXXXXXXXXX" -offset indent
2685.It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
2686.It Sx \&It Ta \&No Ta Yes  Ta closed by Sx \&It , Sx \&El
2687.It Sx \&Nd Ta \&No Ta \&No Ta closed by Sx \&Sh
2688.It Sx \&Nm Ta \&No Ta Yes  Ta closed by Sx \&Nm , Sx \&Sh , Sx \&Ss
2689.It Sx \&Sh Ta \&No Ta Yes  Ta closed by Sx \&Sh
2690.It Sx \&Ss Ta \&No Ta Yes  Ta closed by Sx \&Sh , Sx \&Ss
2691.El
2692.Pp
2693Note that the
2694.Sx \&Nm
2695macro is a
2696.Sx Block full-implicit
2697macro only when invoked as the first macro
2698in a
2699.Em SYNOPSIS
2700section line, else it is
2701.Sx In-line .
2702.Ss Block partial-explicit
2703Like block full-explicit, but also with single-line scope.
2704Each has at least a body and, in limited circumstances, a head
2705.Po
2706.Sx \&Fo ,
2707.Sx \&Eo
2708.Pc
2709and/or tail
2710.Pq Sx \&Ec .
2711.Bd -literal -offset indent
2712\&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
2713\(lBbody...\(rB
2714\&.Yc \(lBtail...\(rB
2715
2716\&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB \
2717\(lBbody...\(rB \&Yc \(lBtail...\(rB
2718.Ed
2719.Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXX" -offset indent
2720.It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
2721.It Sx \&Ac  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Ao
2722.It Sx \&Ao  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Ac
2723.It Sx \&Bc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Bo
2724.It Sx \&Bo  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Bc
2725.It Sx \&Brc Ta    Yes      Ta    Yes      Ta    opened by Sx \&Bro
2726.It Sx \&Bro Ta    Yes      Ta    Yes      Ta    closed by Sx \&Brc
2727.It Sx \&Dc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Do
2728.It Sx \&Do  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Dc
2729.It Sx \&Ec  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Eo
2730.It Sx \&Eo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Ec
2731.It Sx \&Fc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Fo
2732.It Sx \&Fo  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Fc
2733.It Sx \&Oc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Oo
2734.It Sx \&Oo  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Oc
2735.It Sx \&Pc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Po
2736.It Sx \&Po  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Pc
2737.It Sx \&Qc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Oo
2738.It Sx \&Qo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Oc
2739.It Sx \&Re  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Rs
2740.It Sx \&Rs  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Re
2741.It Sx \&Sc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&So
2742.It Sx \&So  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Sc
2743.It Sx \&Xc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Xo
2744.It Sx \&Xo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Xc
2745.El
2746.Ss Block partial-implicit
2747Like block full-implicit, but with single-line scope closed by the
2748end of the line.
2749.Bd -literal -offset indent
2750\&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBbody...\(rB \(lBres...\(rB
2751.Ed
2752.Bl -column "MacroX" "CallableX" "ParsedX" -offset indent
2753.It Em Macro Ta Em Callable Ta Em Parsed
2754.It Sx \&Aq  Ta    Yes      Ta    Yes
2755.It Sx \&Bq  Ta    Yes      Ta    Yes
2756.It Sx \&Brq Ta    Yes      Ta    Yes
2757.It Sx \&D1  Ta    \&No     Ta    \&Yes
2758.It Sx \&Dl  Ta    \&No     Ta    Yes
2759.It Sx \&Dq  Ta    Yes      Ta    Yes
2760.It Sx \&Op  Ta    Yes      Ta    Yes
2761.It Sx \&Pq  Ta    Yes      Ta    Yes
2762.It Sx \&Ql  Ta    Yes      Ta    Yes
2763.It Sx \&Qq  Ta    Yes      Ta    Yes
2764.It Sx \&Sq  Ta    Yes      Ta    Yes
2765.It Sx \&Vt  Ta    Yes      Ta    Yes
2766.El
2767.Pp
2768Note that the
2769.Sx \&Vt
2770macro is a
2771.Sx Block partial-implicit
2772only when invoked as the first macro
2773in a
2774.Em SYNOPSIS
2775section line, else it is
2776.Sx In-line .
2777.Ss Special block macro
2778The
2779.Sx \&Ta
2780macro can only be used below
2781.Sx \&It
2782in
2783.Sx \&Bl Fl column
2784lists.
2785It delimits blocks representing table cells;
2786these blocks have bodies, but no heads.
2787.Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXX" -offset indent
2788.It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
2789.It Sx \&Ta  Ta    Yes      Ta    Yes    Ta closed by Sx \&Ta , Sx \&It
2790.El
2791.Ss In-line
2792Closed by the end of the line, fixed argument lengths,
2793and/or subsequent macros.
2794In-line macros have only text children.
2795If a number (or inequality) of arguments is
2796.Pq n ,
2797then the macro accepts an arbitrary number of arguments.
2798.Bd -literal -offset indent
2799\&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB \(lBres...\(rB
2800
2801\&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB Yc...
2802
2803\&.Yo \(lB\-arg \(lBval...\(rB\(rB arg0 arg1 argN
2804.Ed
2805.Bl -column "MacroX" "CallableX" "ParsedX" "Arguments" -offset indent
2806.It Em Macro Ta Em Callable Ta Em Parsed Ta Em Arguments
2807.It Sx \&%A  Ta    \&No     Ta    \&No     Ta    >0
2808.It Sx \&%B  Ta    \&No     Ta    \&No     Ta    >0
2809.It Sx \&%C  Ta    \&No     Ta    \&No     Ta    >0
2810.It Sx \&%D  Ta    \&No     Ta    \&No     Ta    >0
2811.It Sx \&%I  Ta    \&No     Ta    \&No     Ta    >0
2812.It Sx \&%J  Ta    \&No     Ta    \&No     Ta    >0
2813.It Sx \&%N  Ta    \&No     Ta    \&No     Ta    >0
2814.It Sx \&%O  Ta    \&No     Ta    \&No     Ta    >0
2815.It Sx \&%P  Ta    \&No     Ta    \&No     Ta    >0
2816.It Sx \&%Q  Ta    \&No     Ta    \&No     Ta    >0
2817.It Sx \&%R  Ta    \&No     Ta    \&No     Ta    >0
2818.It Sx \&%T  Ta    \&No     Ta    \&No     Ta    >0
2819.It Sx \&%U  Ta    \&No     Ta    \&No     Ta    >0
2820.It Sx \&%V  Ta    \&No     Ta    \&No     Ta    >0
2821.It Sx \&Ad  Ta    Yes      Ta    Yes      Ta    >0
2822.It Sx \&An  Ta    Yes      Ta    Yes      Ta    >0
2823.It Sx \&Ap  Ta    Yes      Ta    Yes      Ta    0
2824.It Sx \&Ar  Ta    Yes      Ta    Yes      Ta    n
2825.It Sx \&At  Ta    Yes      Ta    Yes      Ta    1
2826.It Sx \&Bsx Ta    Yes      Ta    Yes      Ta    n
2827.It Sx \&Bt  Ta    \&No     Ta    \&No     Ta    0
2828.It Sx \&Bx  Ta    Yes      Ta    Yes      Ta    n
2829.It Sx \&Cd  Ta    Yes      Ta    Yes      Ta    >0
2830.It Sx \&Cm  Ta    Yes      Ta    Yes      Ta    >0
2831.It Sx \&Db  Ta    \&No     Ta    \&No     Ta    1
2832.It Sx \&Dd  Ta    \&No     Ta    \&No     Ta    n
2833.It Sx \&Dt  Ta    \&No     Ta    \&No     Ta    n
2834.It Sx \&Dv  Ta    Yes      Ta    Yes      Ta    >0
2835.It Sx \&Dx  Ta    Yes      Ta    Yes      Ta    n
2836.It Sx \&Em  Ta    Yes      Ta    Yes      Ta    >0
2837.It Sx \&En  Ta    \&No     Ta    \&No     Ta    0
2838.It Sx \&Er  Ta    Yes      Ta    Yes      Ta    >0
2839.It Sx \&Es  Ta    \&No     Ta    \&No     Ta    0
2840.It Sx \&Ev  Ta    Yes      Ta    Yes      Ta    >0
2841.It Sx \&Ex  Ta    \&No     Ta    \&No     Ta    n
2842.It Sx \&Fa  Ta    Yes      Ta    Yes      Ta    >0
2843.It Sx \&Fd  Ta    \&No     Ta    \&No     Ta    >0
2844.It Sx \&Fl  Ta    Yes      Ta    Yes      Ta    n
2845.It Sx \&Fn  Ta    Yes      Ta    Yes      Ta    >0
2846.It Sx \&Fr  Ta    \&No     Ta    \&No     Ta    n
2847.It Sx \&Ft  Ta    Yes      Ta    Yes      Ta    >0
2848.It Sx \&Fx  Ta    Yes      Ta    Yes      Ta    n
2849.It Sx \&Hf  Ta    \&No     Ta    \&No     Ta    n
2850.It Sx \&Ic  Ta    Yes      Ta    Yes      Ta    >0
2851.It Sx \&In  Ta    \&No     Ta    \&No     Ta    1
2852.It Sx \&Lb  Ta    \&No     Ta    \&No     Ta    1
2853.It Sx \&Li  Ta    Yes      Ta    Yes      Ta    >0
2854.It Sx \&Lk  Ta    Yes      Ta    Yes      Ta    >0
2855.It Sx \&Lp  Ta    \&No     Ta    \&No     Ta    0
2856.It Sx \&Ms  Ta    Yes      Ta    Yes      Ta    >0
2857.It Sx \&Mt  Ta    Yes      Ta    Yes      Ta    >0
2858.It Sx \&Nm  Ta    Yes      Ta    Yes      Ta    n
2859.It Sx \&No  Ta    Yes      Ta    Yes      Ta    0
2860.It Sx \&Ns  Ta    Yes      Ta    Yes      Ta    0
2861.It Sx \&Nx  Ta    Yes      Ta    Yes      Ta    n
2862.It Sx \&Os  Ta    \&No     Ta    \&No     Ta    n
2863.It Sx \&Ot  Ta    \&No     Ta    \&No     Ta    n
2864.It Sx \&Ox  Ta    Yes      Ta    Yes      Ta    n
2865.It Sx \&Pa  Ta    Yes      Ta    Yes      Ta    n
2866.It Sx \&Pf  Ta    Yes      Ta    Yes      Ta    1
2867.It Sx \&Pp  Ta    \&No     Ta    \&No     Ta    0
2868.It Sx \&Rv  Ta    \&No     Ta    \&No     Ta    n
2869.It Sx \&Sm  Ta    \&No     Ta    \&No     Ta    1
2870.It Sx \&St  Ta    \&No     Ta    Yes      Ta    1
2871.It Sx \&Sx  Ta    Yes      Ta    Yes      Ta    >0
2872.It Sx \&Sy  Ta    Yes      Ta    Yes      Ta    >0
2873.It Sx \&Tn  Ta    Yes      Ta    Yes      Ta    >0
2874.It Sx \&Ud  Ta    \&No     Ta    \&No     Ta    0
2875.It Sx \&Ux  Ta    Yes      Ta    Yes      Ta    n
2876.It Sx \&Va  Ta    Yes      Ta    Yes      Ta    n
2877.It Sx \&Vt  Ta    Yes      Ta    Yes      Ta    >0
2878.It Sx \&Xr  Ta    Yes      Ta    Yes      Ta    >0
2879.It Sx \&br  Ta    \&No     Ta    \&No     Ta    0
2880.It Sx \&sp  Ta    \&No     Ta    \&No     Ta    1
2881.El
2882.Ss Delimiters
2883When a macro argument consists of one single input character
2884considered as a delimiter, the argument gets special handling.
2885This does not apply when delimiters appear in arguments containing
2886more than one character.
2887Consequently, to prevent special handling and just handle it
2888like any other argument, a delimiter can be escaped by prepending
2889a zero-width space
2890.Pq Sq \e& .
2891In text lines, delimiters never need escaping, but may be used
2892as normal punctuation.
2893.Pp
2894For many macros, when the leading arguments are opening delimiters,
2895these delimiters are put before the macro scope,
2896and when the trailing arguments are closing delimiters,
2897these delimiters are put after the macro scope.
2898For example,
2899.Pp
2900.D1 Pf \. \&Aq "( [ word ] ) ."
2901.Pp
2902renders as:
2903.Pp
2904.D1 Aq ( [ word ] ) .
2905.Pp
2906Opening delimiters are:
2907.Pp
2908.Bl -tag -width Ds -offset indent -compact
2909.It \&(
2910left parenthesis
2911.It \&[
2912left bracket
2913.El
2914.Pp
2915Closing delimiters are:
2916.Pp
2917.Bl -tag -width Ds -offset indent -compact
2918.It \&.
2919period
2920.It \&,
2921comma
2922.It \&:
2923colon
2924.It \&;
2925semicolon
2926.It \&)
2927right parenthesis
2928.It \&]
2929right bracket
2930.It \&?
2931question mark
2932.It \&!
2933exclamation mark
2934.El
2935.Pp
2936Note that even a period preceded by a backslash
2937.Pq Sq \e.\&
2938gets this special handling; use
2939.Sq \e&.
2940to prevent that.
2941.Pp
2942Many in-line macros interrupt their scope when they encounter
2943delimiters, and resume their scope when more arguments follow that
2944are not delimiters.
2945For example,
2946.Pp
2947.D1 Pf \. \&Fl "a ( b | c \e*(Ba d ) e"
2948.Pp
2949renders as:
2950.Pp
2951.D1 Fl a ( b | c \*(Ba d ) e
2952.Pp
2953This applies to both opening and closing delimiters,
2954and also to the middle delimiter:
2955.Pp
2956.Bl -tag -width Ds -offset indent -compact
2957.It \&|
2958vertical bar
2959.El
2960.Pp
2961As a special case, the predefined string \e*(Ba is handled and rendered
2962in the same way as a plain
2963.Sq \&|
2964character.
2965Using this predefined string is not recommended in new manuals.
2966.Ss Font handling
2967In
2968.Nm
2969documents, usage of semantic markup is recommended in order to have
2970proper fonts automatically selected; only when no fitting semantic markup
2971is available, consider falling back to
2972.Sx Physical markup
2973macros.
2974Whenever any
2975.Nm
2976macro switches the
2977.Xr roff 7
2978font mode, it will automatically restore the previous font when exiting
2979its scope.
2980Manually switching the font using the
2981.Xr roff 7
2982.Ql \ef
2983font escape sequences is never required.
2984.Sh COMPATIBILITY
2985This section documents compatibility between mandoc and other other
2986troff implementations, at this time limited to GNU troff
2987.Pq Qq groff .
2988The term
2989.Qq historic groff
2990refers to groff versions before 1.17,
2991which featured a significant update of the
2992.Pa doc.tmac
2993file.
2994.Pp
2995Heirloom troff, the other significant troff implementation accepting
2996\-mdoc, is similar to historic groff.
2997.Pp
2998The following problematic behaviour is found in groff:
2999.ds hist (Historic groff only.)
3000.Pp
3001.Bl -dash -compact
3002.It
3003Display macros
3004.Po
3005.Sx \&Bd ,
3006.Sx \&Dl ,
3007and
3008.Sx \&D1
3009.Pc
3010may not be nested.
3011\*[hist]
3012.It
3013.Sx \&At
3014with unknown arguments produces no output at all.
3015\*[hist]
3016Newer groff and mandoc print
3017.Qq AT&T UNIX
3018and the arguments.
3019.It
3020.Sx \&Bl Fl column
3021does not recognise trailing punctuation characters when they immediately
3022precede tabulator characters, but treats them as normal text and
3023outputs a space before them.
3024.It
3025.Sx \&Bd Fl ragged compact
3026does not start a new line.
3027\*[hist]
3028.It
3029.Sx \&Dd
3030with non-standard arguments behaves very strangely.
3031When there are three arguments, they are printed verbatim.
3032Any other number of arguments is replaced by the current date,
3033but without any arguments the string
3034.Dq Epoch
3035is printed.
3036.It
3037.Sx \&Fl
3038does not print a dash for an empty argument.
3039\*[hist]
3040.It
3041.Sx \&Fn
3042does not start a new line unless invoked as the line macro in the
3043.Em SYNOPSIS
3044section.
3045\*[hist]
3046.It
3047.Sx \&Fo
3048with
3049.Pf non- Sx \&Fa
3050children causes inconsistent spacing between arguments.
3051In mandoc, a single space is always inserted between arguments.
3052.It
3053.Sx \&Ft
3054in the
3055.Em SYNOPSIS
3056causes inconsistent vertical spacing, depending on whether a prior
3057.Sx \&Fn
3058has been invoked.
3059See
3060.Sx \&Ft
3061and
3062.Sx \&Fn
3063for the normalised behaviour in mandoc.
3064.It
3065.Sx \&In
3066ignores additional arguments and is not treated specially in the
3067.Em SYNOPSIS .
3068\*[hist]
3069.It
3070.Sx \&It
3071sometimes requires a
3072.Fl nested
3073flag.
3074\*[hist]
3075In new groff and mandoc, any list may be nested by default and
3076.Fl enum
3077lists will restart the sequence only for the sub-list.
3078.It
3079.Sx \&Li
3080followed by a delimiter is incorrectly used in some manuals
3081instead of properly quoting that character, which sometimes works with
3082historic groff.
3083.It
3084.Sx \&Lk
3085only accepts a single link-name argument; the remainder is misformatted.
3086.It
3087.Sx \&Pa
3088does not format its arguments when used in the FILES section under
3089certain list types.
3090.It
3091.Sx \&Ta
3092can only be called by other macros, but not at the beginning of a line.
3093.It
3094.Sx \&%C
3095is not implemented.
3096.It
3097Historic groff only allows up to eight or nine arguments per macro input
3098line, depending on the exact situation.
3099Providing more arguments causes garbled output.
3100The number of arguments on one input line is not limited with mandoc.
3101.It
3102Historic groff has many un-callable macros.
3103Most of these (excluding some block-level macros) are callable
3104in new groff and mandoc.
3105.It
3106.Sq \(ba
3107(vertical bar) is not fully supported as a delimiter.
3108\*[hist]
3109.It
3110.Sq \ef
3111.Pq font face
3112and
3113.Sq \ef
3114.Pq font family face
3115.Sx Text Decoration
3116escapes behave irregularly when specified within line-macro scopes.
3117.It
3118Negative scaling units return to prior lines.
3119Instead, mandoc truncates them to zero.
3120.El
3121.Pp
3122The following features are unimplemented in mandoc:
3123.Pp
3124.Bl -dash -compact
3125.It
3126.Sx \&Bd
3127.Fl file Ar file .
3128.It
3129.Sx \&Bd
3130.Fl offset Ar center
3131and
3132.Fl offset Ar right .
3133Groff does not implement centred and flush-right rendering either,
3134but produces large indentations.
3135.It
3136The
3137.Sq \eh
3138.Pq horizontal position ,
3139.Sq \ev
3140.Pq vertical position ,
3141.Sq \em
3142.Pq text colour ,
3143.Sq \eM
3144.Pq text filling colour ,
3145.Sq \ez
3146.Pq zero-length character ,
3147.Sq \ew
3148.Pq string length ,
3149.Sq \ek
3150.Pq horizontal position marker ,
3151.Sq \eo
3152.Pq text overstrike ,
3153and
3154.Sq \es
3155.Pq text size
3156escape sequences are all discarded in mandoc.
3157.It
3158The
3159.Sq \ef
3160scaling unit is accepted by mandoc, but rendered as the default unit.
3161.It
3162In quoted literals, groff allows pairwise double-quotes to produce a
3163standalone double-quote in formatted output.
3164This is not supported by mandoc.
3165.El
3166.Sh SEE ALSO
3167.Xr man 1 ,
3168.Xr mandoc 1 ,
3169.Xr eqn 7 ,
3170.Xr man 7 ,
3171.Xr mandoc_char 7 ,
3172.Xr roff 7 ,
3173.Xr tbl 7
3174.Sh HISTORY
3175The
3176.Nm
3177language first appeared as a troff macro package in
3178.Bx 4.4 .
3179It was later significantly updated by Werner Lemberg and Ruslan Ermilov
3180in groff-1.17.
3181The standalone implementation that is part of the
3182.Xr mandoc 1
3183utility written by Kristaps Dzonsons appeared in
3184.Ox 4.6 .
3185.Sh AUTHORS
3186The
3187.Nm
3188reference was written by
3189.An Kristaps Dzonsons ,
3190.Mt kristaps@bsd.lv .
3191