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version 1.19, 2009/03/27 14:56:15 version 1.208, 2011/09/02 19:37:35
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 .\" $Id$  .\"     $Id$
 .\"  .\"
 .\" Copyright (c) 2009 Kristaps Dzonsons <kristaps@openbsd.org>  .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
   .\" Copyright (c) 2010 Ingo Schwarze <schwarze@openbsd.org>
 .\"  .\"
 .\" Permission to use, copy, modify, and distribute this software for any  .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the  .\" purpose with or without fee is hereby granted, provided that the above
 .\" above copyright notice and this permission notice appear in all  .\" copyright notice and this permission notice appear in all copies.
 .\" copies.  
 .\"  .\"
 .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL  .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 .\" WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED  .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 .\" WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE  .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 .\" AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL  .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 .\" DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR  .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 .\" PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER  .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR  .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\" PERFORMANCE OF THIS SOFTWARE.  .\"
 .\"  
 .Dd $Mdocdate$  .Dd $Mdocdate$
 .Dt mdoc 7  .Dt MDOC 7
 .Os  .Os
 .\" SECTION  
 .Sh NAME  .Sh NAME
 .Nm mdoc  .Nm mdoc
 .Nd mdoc language reference  .Nd mdoc language reference
 .\" SECTION  
 .Sh DESCRIPTION  .Sh DESCRIPTION
 The  The
 .Nm mdoc  .Nm mdoc
 language is used to format  language is used to format
 .Bx  .Bx
 .Ux  .Ux
 manuals.  In this reference document, we describe the syntax, ontology  manuals.
 and structure of the  This reference document describes its syntax, structure, and
   usage.
   The reference implementation for
 .Nm  .Nm
 language.  formatting is
 .\" PARAGRAPH  .Xr mandoc 1 ;
   the
   .Sx COMPATIBILITY
   section describes compatibility with other implementations.
 .Pp  .Pp
 An  An
 .Nm  .Nm
 document follows simple rules:  lines beginning with the control  document follows simple rules: lines beginning with the control
 character  character
 .Sq \.  .Sq \&.
 are parsed for macros.  Other lines are interpreted within the scope of  are parsed for macros.
 prior macros:  Lines not beginning with the control character are
 .Bd -literal -offset XXX  interpreted within the scope of prior macros:
   .Bd -literal -offset indent
 \&.Sh Macro lines change control state.  \&.Sh Macro lines change control state.
 Other lines are interpreted within the current state.  Text lines are interpreted within the current state.
 .Ed  .Ed
 .\" SECTION  .Sh LANGUAGE SYNTAX
 .Sh INPUT ENCODING  
 .Nm  .Nm
 documents may contain only graphable 7-bit ASCII characters, the space  documents may contain only graphable 7-bit ASCII characters, the space
   character, and, in certain circumstances, the tab character.
   The back-space character
   .Sq \e
   indicates the start of an escape sequence for
   .Sx Comments ,
   .Sx Predefined Strings ,
   and
   .Sx Special Characters .
   .Ss Comments
   Text following an escaped double-quote
   .Sq \e\(dq ,
   whether in a macro or text line, is ignored to the end of
   line.
   A macro line beginning with a control character and comment escape
   .Sq \&.\e\(dq
   is also ignored.
   Furthermore,
   macro lines with only a control character and optional trailing
   whitespace are
   stripped from input.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.\e\(dq This is a comment line.
   \&.\e\(dq The next line is ignored:
   \&.
   \&.Em Emphasis \e\(dq This is also a comment.
   .Ed
   .Ss Special Characters
   Special characters are used to encode special glyphs and are rendered
   differently across output media.
   They may occur in both macro and text lines.
   Sequences begin with the escape character
   .Sq \e
   followed by either an open-parenthesis
   .Sq \&(
   for two-character sequences; an open-bracket
   .Sq \&[
   for n-character sequences (terminated at a close-bracket
   .Sq \&] ) ;
   or a single one character sequence.
   .Pp
   Examples:
   .Bl -tag -width Ds -offset indent -compact
   .It Li \e(em
   Two-letter em dash escape.
   .It Li \ee
   One-letter backslash escape.
   .El
   .Pp
   See
   .Xr mandoc_char 7
   for a complete list.
   .Ss Text Decoration
   Terms may be text-decorated using the
   .Sq \ef
   escape followed by an indicator: B (bold), I (italic), R (regular), or P
   (revert to previous mode).
   A numerical representation 3, 2, or 1 (bold, italic, and regular,
   respectively) may be used instead.
   If a macro opens a font scope after calling
   .Sq \ef ,
   such as with
   .Sx \&Bf ,
   the
   .Sq \ef
   mode will be restored upon exiting the
   .Sx \&Bf
   scope.
   .Pp
   Examples:
   .Bl -tag -width Ds -offset indent -compact
   .It Li \efBbold\efR
   Write in bold, then switch to regular font mode.
   .It Li \efIitalic\efP
   Write in italic, then return to previous font mode.
   .El
   .Pp
   Text decoration is
   .Em not
   recommended for
   .Nm ,
   which encourages semantic annotation.
   .Ss Predefined Strings
   Predefined strings, like
   .Sx Special Characters ,
   mark special output glyphs.
   Predefined strings are escaped with the slash-asterisk,
   .Sq \e* :
   single-character
   .Sq \e*X ,
   two-character
   .Sq \e*(XX ,
   and N-character
   .Sq \e*[N] .
   .Pp
   Examples:
   .Bl -tag -width Ds -offset indent -compact
   .It Li \e*(Am
   Two-letter ampersand predefined string.
   .It Li \e*q
   One-letter double-quote predefined string.
   .El
   .Pp
   These strings are set using
   .Xr roff 7 ,
   although
   .Nm
   consists of several pre-set escapes listed in
   .Xr mandoc_char 7 .
   .Ss Whitespace
   Whitespace consists of the space character.
   In text lines, whitespace is preserved within a line.
   In macro lines, whitespace delimits arguments and is discarded.
   .Pp
   Unescaped trailing spaces are stripped from text line input unless in a
   literal context.
   In general, trailing whitespace on any input line is discouraged for
   reasons of portability.
   In the rare case that a blank character is needed at the end of an
   input line, it may be forced by
   .Sq \e\ \e& .
   .Pp
   In general, space characters can be rendered as literal
   characters by using non-breaking space escapes or
   .Sx Quotation .
   .Pp
   Blank text lines, which may include whitespace, are only permitted
   within literal contexts.
   If the first character of a text line is a space, that line is printed
   with a leading newline.
   .Ss Quotation
   Macro arguments may be quoted with double-quotes to so that the
   enclosed text is one literal term.
   Quoted text, even if whitespace or if it would cause a macro invocation
   when unquoted, is considered literal text.
   .Pp
   A quoted argument begins with a double-quote preceded by whitespace.
   The next double-quote not pairwise adjacent to another double-quote
   terminates the literal, regardless of surrounding whitespace.
   .Pp
   Examples:
   .Bl -tag -width Ds -offset indent -compact
   .It Li .Fn strlen \(dqconst char *s\(dq
   Group arguments
   .Qq const char *s
   into one function argument.
   If unspecified,
   .Qq const ,
   .Qq char ,
   and
   .Qq *s
   would be considered separate arguments.
   .Pq See Sx \&Fn .
   .It Li .Op \(dqFl a\(dq
   Consider
   .Qq \&Fl a
   as literal text instead of a flag macro.
   .Pq Aee Sx \&Op , \&Fl .
   .El
   .Ss Scaling Widths
   Many macros support scaled widths for their arguments.
   The syntax for a scaled width is
   .Sq Li [+-]?[0-9]*.[0-9]*[:unit:] ,
   where a decimal must be preceded or proceeded by at least one digit.
   Negative numbers, while accepted, are truncated to zero.
   .Pp
   The following scaling units are accepted:
   .Pp
   .Bl -tag -width Ds -offset indent -compact
   .It c
   centimetre
   .It i
   inch
   .It P
   pica (~1/6 inch)
   .It p
   point (~1/72 inch)
   .It f
   synonym for
   .Sq u
   .It v
   default vertical span
   .It m
   width of rendered
   .Sq m
   .Pq em
 character  character
 .Sq \  ,  .It n
 and, in certain circumstances, the tab character  width of rendered
 .Sq \et .  .Sq n
 All manuals must have  .Pq en
 .Sq \en  character
 line termination.  .It u
   default horizontal span
   .It M
   mini-em (~1/100 em)
   .El
 .Pp  .Pp
 The only time a blank line is acceptable is within  Using anything other than
 the context of  .Sq m ,
 .Sq \&.Bd \-literal  .Sq n ,
   .Sq u ,
 or  or
 .Sq \&.Bd \-unfilled .  .Sq v
   is necessarily non-portable across output media.
   See
   .Sx COMPATIBILITY .
 .Pp  .Pp
 Tab characters  Examples:
 .Pq \et  .Bl -tag -width Ds -offset indent -compact
 are only acceptable when delimiting  .It Li \&.Bl -tag -width 2i
 .Sq \&.Bl \-column  two-inch tagged list indentation
 and in  .Pq see Sx \&Bl
 .Sq \&.Bd \-literal  .It Li \&.sp 2v
   two vertical spaces
   .Pq see Sx \&sp
   .El
   .Ss Sentence Spacing
   Sentences should terminate at the end of an input line.
   By doing this, a formatter will be able to apply the proper amount of
   spacing after the end of sentence (unescaped) period, exclamation mark,
   or question mark followed by zero or more non-sentence closing
   delimiters
   .Po
   .Sq \&) ,
   .Sq \&] ,
   .Sq \&' ,
   .Sq \&"
   .Pc .
   .Pp
   The proper spacing is also intelligently preserved if a sentence ends at
   the boundary of a macro line.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   Do not end sentences mid-line like this.  Instead,
   end a sentence like this.
   A macro would end like this:
   \&.Xr mandoc 1 \&.
   .Ed
   .Sh MANUAL STRUCTURE
   A well-formed
   .Nm
   document consists of a document prologue followed by one or more
   sections.
   .Pp
   The prologue, which consists of the
   .Sx \&Dd ,
   .Sx \&Dt ,
   and
   .Sx \&Os
   macros in that order, is required for every document.
   .Pp
   The first section (sections are denoted by
   .Sx \&Sh )
   must be the NAME section, consisting of at least one
   .Sx \&Nm
   followed by
   .Sx \&Nd .
   .Pp
   Following that, convention dictates specifying at least the
   .Em SYNOPSIS
   and
   .Em DESCRIPTION
   sections, although this varies between manual sections.
   .Pp
   The following is a well-formed skeleton
   .Nm
   file for a utility
   .Qq progname :
   .Bd -literal -offset indent
   \&.Dd $\&Mdocdate$
   \&.Dt PROGNAME section
   \&.Os
   \&.Sh NAME
   \&.Nm progname
   \&.Nd one line about what it does
   \&.\e\(dq .Sh LIBRARY
   \&.\e\(dq For sections 2, 3, & 9 only.
   \&.\e\(dq Not used in OpenBSD.
   \&.Sh SYNOPSIS
   \&.Nm progname
   \&.Op Fl options
   \&.Ar
   \&.Sh DESCRIPTION
   The
   \&.Nm
   utility processes files ...
   \&.\e\(dq .Sh IMPLEMENTATION NOTES
   \&.\e\(dq Not used in OpenBSD.
   \&.\e\(dq .Sh RETURN VALUES
   \&.\e\(dq For sections 2, 3, & 9 only.
   \&.\e\(dq .Sh ENVIRONMENT
   \&.\e\(dq For sections 1, 6, 7, & 8 only.
   \&.\e\(dq .Sh FILES
   \&.\e\(dq .Sh EXIT STATUS
   \&.\e\(dq For sections 1, 6, & 8 only.
   \&.\e\(dq .Sh EXAMPLES
   \&.\e\(dq .Sh DIAGNOSTICS
   \&.\e\(dq For sections 1, 4, 6, 7, & 8 only.
   \&.\e\(dq .Sh ERRORS
   \&.\e\(dq For sections 2, 3, & 9 only.
   \&.\e\(dq .Sh SEE ALSO
   \&.\e\(dq .Xr foobar 1
   \&.\e\(dq .Sh STANDARDS
   \&.\e\(dq .Sh HISTORY
   \&.\e\(dq .Sh AUTHORS
   \&.\e\(dq .Sh CAVEATS
   \&.\e\(dq .Sh BUGS
   \&.\e\(dq .Sh SECURITY CONSIDERATIONS
   \&.\e\(dq Not used in OpenBSD.
   .Ed
   .Pp
   The sections in an
   .Nm
   document are conventionally ordered as they appear above.
   Sections should be composed as follows:
   .Bl -ohang -offset Ds
   .It Em NAME
   The name(s) and a one line description of the documented material.
   The syntax for this as follows:
   .Bd -literal -offset indent
   \&.Nm name0 ,
   \&.Nm name1 ,
   \&.Nm name2
   \&.Nd a one line description
   .Ed
   .Pp
   Multiple
   .Sq \&Nm
   names should be separated by commas.
   .Pp
   The
   .Sx \&Nm
   macro(s) must precede the
   .Sx \&Nd
   macro.
   .Pp
   See
   .Sx \&Nm
   and
   .Sx \&Nd .
   .It Em LIBRARY
   The name of the library containing the documented material, which is
   assumed to be a function in a section 2, 3, or 9 manual.
   The syntax for this is as follows:
   .Bd -literal -offset indent
   \&.Lb libarm
   .Ed
   .Pp
   See
   .Sx \&Lb .
   .It Em SYNOPSIS
   Documents the utility invocation syntax, function call syntax, or device
   configuration.
   .Pp
   For the first, utilities (sections 1, 6, and 8), this is
   generally structured as follows:
   .Bd -literal -offset indent
   \&.Nm bar
   \&.Op Fl v
   \&.Op Fl o Ar file
   \&.Op Ar
   \&.Nm foo
   \&.Op Fl v
   \&.Op Fl o Ar file
   \&.Op Ar
   .Ed
   .Pp
   Commands should be ordered alphabetically.
   .Pp
   For the second, function calls (sections 2, 3, 9):
   .Bd -literal -offset indent
   \&.In header.h
   \&.Vt extern const char *global;
   \&.Ft "char *"
   \&.Fn foo "const char *src"
   \&.Ft "char *"
   \&.Fn bar "const char *src"
   .Ed
   .Pp
   Ordering of
   .Sx \&In ,
   .Sx \&Vt ,
   .Sx \&Fn ,
   and
   .Sx \&Fo
   macros should follow C header-file conventions.
   .Pp
   And for the third, configurations (section 4):
   .Bd -literal -offset indent
   \&.Cd \(dqit* at isa? port 0x2e\(dq
   \&.Cd \(dqit* at isa? port 0x4e\(dq
   .Ed
   .Pp
   Manuals not in these sections generally don't need a
   .Em SYNOPSIS .
   .Pp
   Some macros are displayed differently in the
   .Em SYNOPSIS
   section, particularly
   .Sx \&Nm ,
   .Sx \&Cd ,
   .Sx \&Fd ,
   .Sx \&Fn ,
   .Sx \&Fo ,
   .Sx \&In ,
   .Sx \&Vt ,
   and
   .Sx \&Ft .
   All of these macros are output on their own line.
   If two such dissimilar macros are pairwise invoked (except for
   .Sx \&Ft
   before
   .Sx \&Fo
 or  or
 .Sq \&.Bd \-unfilled  .Sx \&Fn ) ,
 contexts.  they are separated by a vertical space, unless in the case of
 .\" SUB-SECTION  .Sx \&Fo ,
 .Ss Reserved Characters  .Sx \&Fn ,
 Within a macro line, the following characters are reserved:  and
 .Bl -tag -width 12n -offset XXXX -compact  .Sx \&Ft ,
   which are always separated by vertical space.
   .Pp
   When text and macros following an
   .Sx \&Nm
   macro starting an input line span multiple output lines,
   all output lines but the first will be indented to align
   with the text immediately following the
   .Sx \&Nm
   macro, up to the next
   .Sx \&Nm ,
   .Sx \&Sh ,
   or
   .Sx \&Ss
   macro or the end of an enclosing block, whichever comes first.
   .It Em DESCRIPTION
   This begins with an expansion of the brief, one line description in
   .Em NAME :
   .Bd -literal -offset indent
   The
   \&.Nm
   utility does this, that, and the other.
   .Ed
   .Pp
   It usually follows with a breakdown of the options (if documenting a
   command), such as:
   .Bd -literal -offset indent
   The arguments are as follows:
   \&.Bl \-tag \-width Ds
   \&.It Fl v
   Print verbose information.
   \&.El
   .Ed
   .Pp
   Manuals not documenting a command won't include the above fragment.
   .Pp
   Since the
   .Em DESCRIPTION
   section usually contains most of the text of a manual, longer manuals
   often use the
   .Sx \&Ss
   macro to form subsections.
   In very long manuals, the
   .Em DESCRIPTION
   may be split into multiple sections, each started by an
   .Sx \&Sh
   macro followed by a non-standard section name, and each having
   several subsections, like in the present
   .Nm
   manual.
   .It Em IMPLEMENTATION NOTES
   Implementation-specific notes should be kept here.
   This is useful when implementing standard functions that may have side
   effects or notable algorithmic implications.
   .It Em RETURN VALUES
   This section documents the
   return values of functions in sections 2, 3, and 9.
   .Pp
   See
   .Sx \&Rv .
   .It Em ENVIRONMENT
   Lists the environment variables used by the utility,
   and explains the syntax and semantics of their values.
   The
   .Xr environ 7
   manual provides examples of typical content and formatting.
   .Pp
   See
   .Sx \&Ev .
   .It Em FILES
   Documents files used.
   It's helpful to document both the file name and a short description of how
   the file is used (created, modified, etc.).
   .Pp
   See
   .Sx \&Pa .
   .It Em EXIT STATUS
   This section documents the
   command exit status for section 1, 6, and 8 utilities.
   Historically, this information was described in
   .Em DIAGNOSTICS ,
   a practise that is now discouraged.
   .Pp
   See
   .Sx \&Ex .
   .It Em EXAMPLES
   Example usages.
   This often contains snippets of well-formed, well-tested invocations.
   Make sure that examples work properly!
   .It Em DIAGNOSTICS
   Documents error conditions.
   This is most useful in section 4 manuals.
   Historically, this section was used in place of
   .Em EXIT STATUS
   for manuals in sections 1, 6, and 8; however, this practise is
   discouraged.
   .Pp
   See
   .Sx \&Bl
   .Fl diag .
   .It Em ERRORS
   Documents error handling in sections 2, 3, and 9.
   .Pp
   See
   .Sx \&Er .
   .It Em SEE ALSO
   References other manuals with related topics.
   This section should exist for most manuals.
   Cross-references should conventionally be ordered first by section, then
   alphabetically.
   .Pp
   References to other documentation concerning the topic of the manual page,
   for example authoritative books or journal articles, may also be
   provided in this section.
   .Pp
   See
   .Sx \&Rs
   and
   .Sx \&Xr .
   .It Em STANDARDS
   References any standards implemented or used.
   If not adhering to any standards, the
   .Em HISTORY
   section should be used instead.
   .Pp
   See
   .Sx \&St .
   .It Em HISTORY
   A brief history of the subject, including where it was first implemented,
   and when it was ported to or reimplemented for the operating system at hand.
   .It Em AUTHORS
   Credits to the person or persons who wrote the code and/or documentation.
   Authors should generally be noted by both name and email address.
   .Pp
   See
   .Sx \&An .
   .It Em CAVEATS
   Common misuses and misunderstandings should be explained
   in this section.
   .It Em BUGS
   Known bugs, limitations, and work-arounds should be described
   in this section.
   .It Em SECURITY CONSIDERATIONS
   Documents any security precautions that operators should consider.
   .El
   .Sh MACRO SYNTAX
   Macros are one to three three characters in length and begin with a
   control character,
   .Sq \&. ,
   at the beginning of the line.
   An arbitrary amount of whitespace may sit between the control character
   and the macro name.
   Thus, the following are equivalent:
   .Bd -literal -offset indent
   \&.Pp
   \&.\ \ \ \&Pp
   .Ed
   .Pp
   The syntax of a macro depends on its classification.
   In this section,
   .Sq \-arg
   refers to macro arguments, which may be followed by zero or more
   .Sq parm
   parameters;
   .Sq \&Yo
   opens the scope of a macro; and if specified,
   .Sq \&Yc
   closes it out.
   .Pp
   The
   .Em Callable
   column indicates that the macro may also be called by passing its name
   as an argument to another macro.
   For example,
   .Sq \&.Op \&Fl O \&Ar file
   produces
   .Sq Op Fl O Ar file .
   To prevent a macro call and render the macro name literally,
   escape it by prepending a zero-width space,
   .Sq \e& .
   For example,
   .Sq \&Op \e&Fl O
   produces
   .Sq Op \&Fl O .
   If a macro is not callable but its name appears as an argument
   to another macro, it is interpreted as opaque text.
   For example,
   .Sq \&.Fl \&Sh
   produces
   .Sq Fl \&Sh .
   .Pp
   The
   .Em Parsed
   column indicates whether the macro may call other macros by receiving
   their names as arguments.
   If a macro is not parsed but the name of another macro appears
   as an argument, it is interpreted as opaque text.
   .Pp
   The
   .Em Scope
   column, if applicable, describes closure rules.
   .Ss Block full-explicit
   Multi-line scope closed by an explicit closing macro.
   All macros contains bodies; only
   .Sx \&Bf
   and
   .Pq optionally
   .Sx \&Bl
   contain a head.
   .Bd -literal -offset indent
   \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
   \(lBbody...\(rB
   \&.Yc
   .Ed
   .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXX" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
   .It Sx \&Bd  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ed
   .It Sx \&Bf  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ef
   .It Sx \&Bk  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ek
   .It Sx \&Bl  Ta    \&No     Ta    \&No     Ta    closed by Sx \&El
   .It Sx \&Ed  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bd
   .It Sx \&Ef  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bf
   .It Sx \&Ek  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bk
   .It Sx \&El  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bl
   .El
   .Ss Block full-implicit
   Multi-line scope closed by end-of-file or implicitly by another macro.
   All macros have bodies; some
   .Po
   .Sx \&It Fl bullet ,
   .Fl hyphen ,
   .Fl dash ,
   .Fl enum ,
   .Fl item
   .Pc
   don't have heads; only one
   .Po
   .Sx \&It
   in
   .Sx \&Bl Fl column
   .Pc
   has multiple heads.
   .Bd -literal -offset indent
   \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead... \(lBTa head...\(rB\(rB
   \(lBbody...\(rB
   .Ed
   .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXXXXXXXXX" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
   .It Sx \&It Ta \&No Ta Yes  Ta closed by Sx \&It , Sx \&El
   .It Sx \&Nd Ta \&No Ta \&No Ta closed by Sx \&Sh
   .It Sx \&Nm Ta \&No Ta Yes  Ta closed by Sx \&Nm , Sx \&Sh , Sx \&Ss
   .It Sx \&Sh Ta \&No Ta Yes  Ta closed by Sx \&Sh
   .It Sx \&Ss Ta \&No Ta Yes  Ta closed by Sx \&Sh , Sx \&Ss
   .El
   .Pp
   Note that the
   .Sx \&Nm
   macro is a
   .Sx Block full-implicit
   macro only when invoked as the first macro
   in a
   .Em SYNOPSIS
   section line, else it is
   .Sx In-line .
   .Ss Block partial-explicit
   Like block full-explicit, but also with single-line scope.
   Each has at least a body and, in limited circumstances, a head
   .Po
   .Sx \&Fo ,
   .Sx \&Eo
   .Pc
   and/or tail
   .Pq Sx \&Ec .
   .Bd -literal -offset indent
   \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
   \(lBbody...\(rB
   \&.Yc \(lBtail...\(rB
   
   \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB \
   \(lBbody...\(rB \&Yc \(lBtail...\(rB
   .Ed
   .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXX" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
   .It Sx \&Ac  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Ao
   .It Sx \&Ao  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Ac
   .It Sx \&Bc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Bo
   .It Sx \&Bo  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Bc
   .It Sx \&Brc Ta    Yes      Ta    Yes      Ta    opened by Sx \&Bro
   .It Sx \&Bro Ta    Yes      Ta    Yes      Ta    closed by Sx \&Brc
   .It Sx \&Dc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Do
   .It Sx \&Do  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Dc
   .It Sx \&Ec  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Eo
   .It Sx \&Eo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Ec
   .It Sx \&Fc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Fo
   .It Sx \&Fo  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Fc
   .It Sx \&Oc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Oo
   .It Sx \&Oo  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Oc
   .It Sx \&Pc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Po
   .It Sx \&Po  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Pc
   .It Sx \&Qc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Oo
   .It Sx \&Qo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Oc
   .It Sx \&Re  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Rs
   .It Sx \&Rs  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Re
   .It Sx \&Sc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&So
   .It Sx \&So  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Sc
   .It Sx \&Xc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Xo
   .It Sx \&Xo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Xc
   .El
   .Ss Block partial-implicit
   Like block full-implicit, but with single-line scope closed by the
   end of the line.
   .Bd -literal -offset indent
   \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBbody...\(rB \(lBres...\(rB
   .Ed
   .Bl -column "MacroX" "CallableX" "ParsedX" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed
   .It Sx \&Aq  Ta    Yes      Ta    Yes
   .It Sx \&Bq  Ta    Yes      Ta    Yes
   .It Sx \&Brq Ta    Yes      Ta    Yes
   .It Sx \&D1  Ta    \&No     Ta    \&Yes
   .It Sx \&Dl  Ta    \&No     Ta    Yes
   .It Sx \&Dq  Ta    Yes      Ta    Yes
   .It Sx \&Op  Ta    Yes      Ta    Yes
   .It Sx \&Pq  Ta    Yes      Ta    Yes
   .It Sx \&Ql  Ta    Yes      Ta    Yes
   .It Sx \&Qq  Ta    Yes      Ta    Yes
   .It Sx \&Sq  Ta    Yes      Ta    Yes
   .It Sx \&Vt  Ta    Yes      Ta    Yes
   .El
   .Pp
   Note that the
   .Sx \&Vt
   macro is a
   .Sx Block partial-implicit
   only when invoked as the first macro
   in a
   .Em SYNOPSIS
   section line, else it is
   .Sx In-line .
   .Ss Special block macro
   The
   .Sx \&Ta
   macro can only be used below
   .Sx \&It
   in
   .Sx \&Bl Fl column
   lists.
   It delimits blocks representing table cells;
   these blocks have bodies, but no heads.
   .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXX" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
   .It Sx \&Ta  Ta    Yes      Ta    Yes    Ta closed by Sx \&Ta , Sx \&It
   .El
   .Ss In-line
   Closed by the end of the line, fixed argument lengths,
   and/or subsequent macros.
   In-line macros have only text children.
   If a number (or inequality) of arguments is
   .Pq n ,
   then the macro accepts an arbitrary number of arguments.
   .Bd -literal -offset indent
   \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB \(lBres...\(rB
   
   \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB Yc...
   
   \&.Yo \(lB\-arg \(lBval...\(rB\(rB arg0 arg1 argN
   .Ed
   .Bl -column "MacroX" "CallableX" "ParsedX" "Arguments" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Arguments
   .It Sx \&%A  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%B  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%C  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%D  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%I  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%J  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%N  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%O  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%P  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%Q  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%R  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%T  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%U  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%V  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&Ad  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&An  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Ap  Ta    Yes      Ta    Yes      Ta    0
   .It Sx \&Ar  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&At  Ta    Yes      Ta    Yes      Ta    1
   .It Sx \&Bsx Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Bt  Ta    \&No     Ta    \&No     Ta    0
   .It Sx \&Bx  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Cd  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Cm  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Db  Ta    \&No     Ta    \&No     Ta    1
   .It Sx \&Dd  Ta    \&No     Ta    \&No     Ta    n
   .It Sx \&Dt  Ta    \&No     Ta    \&No     Ta    n
   .It Sx \&Dv  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Dx  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Em  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&En  Ta    \&No     Ta    \&No     Ta    0
   .It Sx \&Er  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Es  Ta    \&No     Ta    \&No     Ta    0
   .It Sx \&Ev  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Ex  Ta    \&No     Ta    \&No     Ta    n
   .It Sx \&Fa  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Fd  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&Fl  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Fn  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Fr  Ta    \&No     Ta    \&No     Ta    n
   .It Sx \&Ft  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Fx  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Hf  Ta    \&No     Ta    \&No     Ta    n
   .It Sx \&Ic  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&In  Ta    \&No     Ta    \&No     Ta    1
   .It Sx \&Lb  Ta    \&No     Ta    \&No     Ta    1
   .It Sx \&Li  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Lk  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Lp  Ta    \&No     Ta    \&No     Ta    0
   .It Sx \&Ms  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Mt  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Nm  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&No  Ta    Yes      Ta    Yes      Ta    0
   .It Sx \&Ns  Ta    Yes      Ta    Yes      Ta    0
   .It Sx \&Nx  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Os  Ta    \&No     Ta    \&No     Ta    n
   .It Sx \&Ot  Ta    \&No     Ta    \&No     Ta    n
   .It Sx \&Ox  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Pa  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Pf  Ta    Yes      Ta    Yes      Ta    1
   .It Sx \&Pp  Ta    \&No     Ta    \&No     Ta    0
   .It Sx \&Rv  Ta    \&No     Ta    \&No     Ta    n
   .It Sx \&Sm  Ta    \&No     Ta    \&No     Ta    1
   .It Sx \&St  Ta    \&No     Ta    Yes      Ta    1
   .It Sx \&Sx  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Sy  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Tn  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Ud  Ta    \&No     Ta    \&No     Ta    0
   .It Sx \&Ux  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Va  Ta    Yes      Ta    Yes      Ta    n
   .It Sx \&Vt  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&Xr  Ta    Yes      Ta    Yes      Ta    >0
   .It Sx \&br  Ta    \&No     Ta    \&No     Ta    0
   .It Sx \&sp  Ta    \&No     Ta    \&No     Ta    1
   .El
   .Ss Delimiters
   When a macro argument consists of one single input character
   considered as a delimiter, the argument gets special handling.
   This does not apply when delimiters appear in arguments containing
   more than one character.
   Consequently, to prevent special handling and just handle it
   like any other argument, a delimiter can be escaped by prepending
   a zero-width space
   .Pq Sq \e& .
   In text lines, delimiters never need escaping, but may be used
   as normal punctuation.
   .Pp
   For many macros, when the leading arguments are opening delimiters,
   these delimiters are put before the macro scope,
   and when the trailing arguments are closing delimiters,
   these delimiters are put after the macro scope.
   For example,
   .Pp
   .D1 Pf \. \&Aq "( [ word ] ) ."
   .Pp
   renders as:
   .Pp
   .D1 Aq ( [ word ] ) .
   .Pp
   Opening delimiters are:
   .Pp
   .Bl -tag -width Ds -offset indent -compact
   .It \&(
   left parenthesis
   .It \&[
   left bracket
   .El
   .Pp
   Closing delimiters are:
   .Pp
   .Bl -tag -width Ds -offset indent -compact
 .It \&.  .It \&.
 .Pq period  period
 .It \&,  .It \&,
 .Pq comma  comma
 .It \&:  .It \&:
 .Pq colon  colon
 .It \&;  .It \&;
 .Pq semicolon  semicolon
 .It \&(  
 .Pq left-parenthesis  
 .It \&)  .It \&)
 .Pq right-parenthesis  right parenthesis
 .It \&[  
 .Pq left-bracket  
 .It \&]  .It \&]
 .Pq right-bracket  right bracket
 .It \&?  .It \&?
 .Pq question  question mark
 .It \&!  .It \&!
 .Pq exclamation  exclamation mark
 .El  .El
 .\" PARAGRAPH  
 .Pp  .Pp
 Use of reserved characters is described in  Note that even a period preceded by a backslash
 .Sx Closure .  .Pq Sq \e.\&
 For general non-reserved use, characters must either be escaped with a  gets this special handling; use
 non-breaking space  .Sq \e&.
 .Pq Sq \e&  to prevent that.
 or, if applicable, an appropriate escape-sequence used.  
 .\" SUB-SECTION  
 .Ss Special Characters  
 Special character sequences begin with the escape character  
 .Sq \e  
 followed by either an open-parenthesis  
 .Sq \&(  
 for two-character sequences; an open-bracket  
 .Sq \&[  
 for n-character sequences (terminated at a close-bracket  
 .Sq \&] ) ;  
 or a single one-character sequence.  
 .Pp  .Pp
 Characters may alternatively be escaped by a slash-asterisk,  Many in-line macros interrupt their scope when they encounter
 .Sq \e* ,  delimiters, and resume their scope when more arguments follow that
 with the same combinations as described above.  This form is deprecated.  are not delimiters.
 .\" SECTION  For example,
 .Sh STRUCTURE  .Pp
 Macros are classified in an ontology described by their scope rules.  .D1 Pf \. \&Fl "a ( b | c \e*(Ba d ) e"
 Some macros are allowed to deviate from their classifications to  .Pp
 preserve backward-compatibility with old macro combinations still found  renders as:
 in the manual corpus.  These are specifically noted on a per-macro  .Pp
 basis.  .D1 Fl a ( b | c \*(Ba d ) e
 .\" SUB-SECTION  .Pp
 .Ss Scope  This applies to both opening and closing delimiters,
 .Bl -inset  and also to the middle delimiter:
 .\" LIST-ITEM  .Pp
 .It Em Block  .Bl -tag -width Ds -offset indent -compact
 macros enclose other block macros, in-line macros or text, and  .It \&|
 may span multiple lines.  vertical bar
 .Bl -inset -offset XXXX  
 .\" LIST-ITEM  
 .It Em Full-block  
 macros always span multiple lines.  They consist of zero or  
 more  
 .Qq heads ,  
 subsequent macros or text on the same line following invocation; an  
 optional  
 .Qq body ,  
 which spans subsequent lines of text or macros; and an optional  
 .Qq tail ,  
 macros or text on the same line following closure.  
 .\" LIST-ITEM  
 .It Em Partial-block  
 macros may span multiple lines.  They consists of a optional  
 .Qq head ,  
 text immediately following invocation; always a  
 .Qq body ,  
 text or macros following the head on the same and subsequent lines; and  
 optionally a  
 .Qq tail ,  
 text immediately following closure.  
 .\" LIST-ITEM  
 .It Em In-line  
 macros may only enclose text and span at most a single line.  
 .El  .El
   .Pp
   As a special case, the predefined string \e*(Ba is handled and rendered
   in the same way as a plain
   .Sq \&|
   character.
   Using this predefined string is not recommended in new manuals.
   .Sh REFERENCE
   This section is a canonical reference of all macros, arranged
   alphabetically.
   For the scoping of individual macros, see
   .Sx MACRO SYNTAX .
   .Ss \&%A
   Author name of an
   .Sx \&Rs
   block.
   Multiple authors should each be accorded their own
   .Sx \%%A
   line.
   Author names should be ordered with full or abbreviated forename(s)
   first, then full surname.
   .Ss \&%B
   Book title of an
   .Sx \&Rs
   block.
   This macro may also be used in a non-bibliographic context when
   referring to book titles.
   .Ss \&%C
   Publication city or location of an
   .Sx \&Rs
   block.
   .Ss \&%D
   Publication date of an
   .Sx \&Rs
   block.
   Recommended formats of arguments are
   .Ar month day , year
   or just
   .Ar year .
   .Ss \&%I
   Publisher or issuer name of an
   .Sx \&Rs
   block.
   .Ss \&%J
   Journal name of an
   .Sx \&Rs
   block.
   .Ss \&%N
   Issue number (usually for journals) of an
   .Sx \&Rs
   block.
   .Ss \&%O
   Optional information of an
   .Sx \&Rs
   block.
   .Ss \&%P
   Book or journal page number of an
   .Sx \&Rs
   block.
   .Ss \&%Q
   Institutional author (school, government, etc.) of an
   .Sx \&Rs
   block.
   Multiple institutional authors should each be accorded their own
   .Sx \&%Q
   line.
   .Ss \&%R
   Technical report name of an
   .Sx \&Rs
   block.
   .Ss \&%T
   Article title of an
   .Sx \&Rs
   block.
   This macro may also be used in a non-bibliographical context when
   referring to article titles.
   .Ss \&%U
   URI of reference document.
   .Ss \&%V
   Volume number of an
   .Sx \&Rs
   block.
   .Ss \&Ac
   Close an
   .Sx \&Ao
   block.
   Does not have any tail arguments.
   .Ss \&Ad
   Memory address.
   Do not use this for postal addresses.
   .Pp
   Examples:
   .Dl \&.Ad [0,$]
   .Dl \&.Ad 0x00000000
   .Ss \&An
   Author name.
   Can be used both for the authors of the program, function, or driver
   documented in the manual, or for the authors of the manual itself.
   Requires either the name of an author or one of the following arguments:
   .Pp
   .Bl -tag -width "-nosplitX" -offset indent -compact
   .It Fl split
   Start a new output line before each subsequent invocation of
   .Sx \&An .
   .It Fl nosplit
   The opposite of
   .Fl split .
 .El  .El
 .\" SUB-SECTION  
 .Ss Closure  
 Closure of a macro's scope depends first on its classification, then  
 on whether it's parsable.  In this table,  
 .Sq BFE  
 refers to block full-explicit and so on.  
 .\" PARAGRAPH  
 .Pp  .Pp
 .Bl -tag -width 12n -offset XXXX -compact  The default is
 .It BPE , BFE  .Fl nosplit .
 corresponding explicit closure macro  The effect of selecting either of the
 .It BFI  .Fl split
 end-of-file or a corresponding implicit closure macro  modes ends at the beginning of the
 .It BPI  .Em AUTHORS
 end-of-line (body may be closed by >0 space-separated  section.
 .Sx Reserved Characters ,  In the
 although block scope will still be open)  .Em AUTHORS
 .It INL  section, the default is
 end-of-line  .Fl nosplit
   for the first author listing and
   .Fl split
   for all other author listings.
   .Pp
   Examples:
   .Dl \&.An -nosplit
   .Dl \&.An Kristaps Dzonsons \&Aq kristaps@bsd.lv
   .Ss \&Ao
   Begin a block enclosed by angle brackets.
   Does not have any head arguments.
   .Pp
   Examples:
   .Dl \&.Fl -key= \&Ns \&Ao \&Ar val \&Ac
   .Pp
   See also
   .Sx \&Aq .
   .Ss \&Ap
   Inserts an apostrophe without any surrounding whitespace.
   This is generally used as a grammatical device when referring to the verb
   form of a function.
   .Pp
   Examples:
   .Dl \&.Fn execve \&Ap d
   .Ss \&Aq
   Encloses its arguments in angle brackets.
   .Pp
   Examples:
   .Dl \&.Fl -key= \&Ns \&Aq \&Ar val
   .Pp
   .Em Remarks :
   this macro is often abused for rendering URIs, which should instead use
   .Sx \&Lk
   or
   .Sx \&Mt ,
   or to note pre-processor
   .Dq Li #include
   statements, which should use
   .Sx \&In .
   .Pp
   See also
   .Sx \&Ao .
   .Ss \&Ar
   Command arguments.
   If an argument is not provided, the string
   .Dq file ...\&
   is used as a default.
   .Pp
   Examples:
   .Dl ".Fl o Ar file"
   .Dl ".Ar"
   .Dl ".Ar arg1 , arg2 ."
   .Pp
   The arguments to the
   .Sx \&Ar
   macro are names and placeholders for command arguments;
   for fixed strings to be passed verbatim as arguments, use
   .Sx \&Fl
   or
   .Sx \&Cm .
   .Ss \&At
   Formats an AT&T version.
   Accepts one optional argument:
   .Pp
   .Bl -tag -width "v[1-7] | 32vX" -offset indent -compact
   .It Cm v[1-7] | 32v
   A version of
   .At .
   .It Cm III
   .At III .
   .It Cm V[.[1-4]]?
   A version of
   .At V .
 .El  .El
 .\" PARAGRAPH  
 .Pp  .Pp
 If a macro (block or in-line) is parsable, it may also be closed out by  Note that these arguments do not begin with a hyphen.
 one of the following scenarios (unless specifically noted otherwise):  
 .\" PARAGRAPH  
 .Pp  .Pp
 .Bl -dash -offset XXXX -compact  Examples:
 .It  .Dl \&.At
 a sequence of >0 space-separated  .Dl \&.At III
 .Sx Reserved Characters ,  .Dl \&.At V.1
   .Pp
   See also
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .Ss \&Bc
   Close a
   .Sx \&Bo
   block.
   Does not have any tail arguments.
   .Ss \&Bd
   Begin a display block.
   Its syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Bd
   .Fl Ns Ar type
   .Op Fl offset Ar width
   .Op Fl compact
   .Ed
   .Pp
   Display blocks are used to select a different indentation and
   justification than the one used by the surrounding text.
   They may contain both macro lines and text lines.
   By default, a display block is preceded by a vertical space.
   .Pp
   The
   .Ar type
   must be one of the following:
   .Bl -tag -width 13n -offset indent
   .It Fl centered
   Produce one output line from each input line, and centre-justify each line.
   Using this display type is not recommended; many
   .Nm
   implementations render it poorly.
   .It Fl filled
   Change the positions of line breaks to fill each line, and left- and
   right-justify the resulting block.
   .It Fl literal
   Produce one output line from each input line,
   and do not justify the block at all.
   Preserve white space as it appears in the input.
   Always use a constant-width font.
   Use this for displaying source code.
   .It Fl ragged
   Change the positions of line breaks to fill each line, and left-justify
   the resulting block.
   .It Fl unfilled
   The same as
   .Fl literal ,
   but using the same font as for normal text, which is a variable width font
   if supported by the output device.
   .El
   .Pp
   The
   .Ar type
   must be provided first.
   Additional arguments may follow:
   .Bl -tag -width 13n -offset indent
   .It Fl offset Ar width
   Indent the display by the
   .Ar width ,
   which may be one of the following:
   .Bl -item
 .It  .It
 another macro,  One of the pre-defined strings
   .Cm indent ,
   the width of a standard indentation (six constant width characters);
   .Cm indent-two ,
   twice
   .Cm indent ;
   .Cm left ,
   which has no effect;
   .Cm right ,
   which justifies to the right margin; or
   .Cm center ,
   which aligns around an imagined centre axis.
 .It  .It
 end-of-line, or  A macro invocation, which selects a predefined width
   associated with that macro.
   The most popular is the imaginary macro
   .Ar \&Ds ,
   which resolves to
   .Sy 6n .
 .It  .It
 completion of a set number of arguments.  A width using the syntax described in
   .Sx Scaling Widths .
   .It
   An arbitrary string, which indents by the length of this string.
 .El  .El
 .\" PARAGRAPH  
 .Pp  .Pp
 If >0 space-separated  When the argument is missing,
 .Sx Reserved Characters  .Fl offset
 are followed by non-reserved characters, the behaviour differs per  is ignored.
 macro.  In general, scope of the macro is closed and re-opened:  .It Fl compact
 subsequent tokens are interpreted as if the scope had just been opened.  Do not assert vertical space before the display.
 In other circumstances, scope is simply closed out.  .El
 .\" SECTION  
 .Sh SYNTAX  
 Macros are two or three characters in length.  The syntax of macro  
 invocation depends on its classification.  
 .Qq \-arg  
 refers to the macro arguments (which may contain zero or more values).  
 In these illustrations,  
 .Sq \&.Yo  
 opens the scope of a macro, and if specified,  
 .Sq \&.Yc  
 closes it out (closure may be implicit at end-of-line or end-of-file).  
 .\" PARAGRAPH  
 .Pp  .Pp
 Block full-explicit (may contain head, body, tail).  Examples:
 .Bd -literal -offset XXXX  .Bd -literal -offset indent
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBhead...\(rB  \&.Bd \-literal \-offset indent \-compact
 \(lBbody...\(rB     Hello       world.
 \&.Yc \(lBtail...\(rB  \&.Ed
 .Ed  .Ed
 .\" PARAGRAPH  
 .Pp  .Pp
 Block full-implicit (may contain zero or more heads, body, no tail).  See also
 .Bd -literal -offset XXXX  .Sx \&D1
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBhead... \(lBTa head...\(rB\(rB  and
 \(lBbody...\(rB  .Sx \&Dl .
 \&.Yc  .Ss \&Bf
   Change the font mode for a scoped block of text.
   Its syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Bf
   .Oo
   .Fl emphasis | literal | symbolic |
   .Cm \&Em | \&Li | \&Sy
   .Oc
 .Ed  .Ed
 .\" PARAGRAPH  
 .Pp  .Pp
 Block partial-explicit (may contain head, multi-line body, tail).  The
 .Bd -literal -offset XXXX  .Fl emphasis
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBhead...\(rB  and
 \(lBbody...\(rB  .Cm \&Em
 \&.Yc \(lBtail...\(rB  argument are equivalent, as are
   .Fl symbolic
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBhead...\(rB \  and
 \(lBbody...\(rB \&Yc \(lBtail...\(rB  .Cm \&Sy ,
   and
   .Fl literal
   and
   .Cm \&Li .
   Without an argument, this macro does nothing.
   The font mode continues until broken by a new font mode in a nested
   scope or
   .Sx \&Ef
   is encountered.
   .Pp
   See also
   .Sx \&Li ,
   .Sx \&Ef ,
   .Sx \&Em ,
   and
   .Sx \&Sy .
   .Ss \&Bk
   For each macro, keep its output together on the same output line,
   until the end of the macro or the end of the input line is reached,
   whichever comes first.
   Line breaks in text lines are unaffected.
   The syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Bk Fl words
   .Pp
   The
   .Fl words
   argument is required; additional arguments are ignored.
   .Pp
   The following example will not break within each
   .Sx \&Op
   macro line:
   .Bd -literal -offset indent
   \&.Bk \-words
   \&.Op Fl f Ar flags
   \&.Op Fl o Ar output
   \&.Ek
 .Ed  .Ed
 .\" PARAGRAPH  
 .Pp  .Pp
 Block partial-implicit (no head, body, no tail).  Note that the body  Be careful in using over-long lines within a keep block!
 section may be followed by zero or more  Doing so will clobber the right margin.
 .Sx Reserved Words .  .Ss \&Bl
 These are in the block scope, but not in the body scope.  Begin a list.
 .Bd -literal -offset XXXX  Lists consist of items specified using the
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBbody...\(rB \(lBreserved...\(rB  .Sx \&It
   macro, containing a head or a body or both.
   The list syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Bl
   .Fl Ns Ar type
   .Op Fl width Ar val
   .Op Fl offset Ar val
   .Op Fl compact
   .Op HEAD ...
 .Ed  .Ed
 .\" PARAGRAPH  
 .Pp  .Pp
 In-lines have \(>=0 scoped arguments.  The list
 .Bd -literal -offset XXX  .Ar type
 \&.Yy \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB  is mandatory and must be specified first.
   The
 \&.Yy \(lB\-arg \(lBval...\(rB\(rB arg0 arg1 argN  .Fl width
   and
   .Fl offset
   arguments accept
   .Sx Scaling Widths
   or use the length of the given string.
   The
   .Fl offset
   is a global indentation for the whole list, affecting both item heads
   and bodies.
   For those list types supporting it, the
   .Fl width
   argument requests an additional indentation of item bodies,
   to be added to the
   .Fl offset .
   Unless the
   .Fl compact
   argument is specified, list entries are separated by vertical space.
   .Pp
   A list must specify one of the following list types:
   .Bl -tag -width 12n -offset indent
   .It Fl bullet
   No item heads can be specified, but a bullet will be printed at the head
   of each item.
   Item bodies start on the same output line as the bullet
   and are indented according to the
   .Fl width
   argument.
   .It Fl column
   A columnated list.
   The
   .Fl width
   argument has no effect; instead, each argument specifies the width
   of one column, using either the
   .Sx Scaling Widths
   syntax or the string length of the argument.
   If the first line of the body of a
   .Fl column
   list is not an
   .Sx \&It
   macro line,
   .Sx \&It
   contexts spanning one input line each are implied until an
   .Sx \&It
   macro line is encountered, at which point items start being interpreted as
   described in the
   .Sx \&It
   documentation.
   .It Fl dash
   Like
   .Fl bullet ,
   except that dashes are used in place of bullets.
   .It Fl diag
   Like
   .Fl inset ,
   except that item heads are not parsed for macro invocations.
   Most often used in the
   .Em DIAGNOSTICS
   section with error constants in the item heads.
   .It Fl enum
   A numbered list.
   No item heads can be specified.
   Formatted like
   .Fl bullet ,
   except that cardinal numbers are used in place of bullets,
   starting at 1.
   .It Fl hang
   Like
   .Fl tag ,
   except that the first lines of item bodies are not indented, but follow
   the item heads like in
   .Fl inset
   lists.
   .It Fl hyphen
   Synonym for
   .Fl dash .
   .It Fl inset
   Item bodies follow items heads on the same line, using normal inter-word
   spacing.
   Bodies are not indented, and the
   .Fl width
   argument is ignored.
   .It Fl item
   No item heads can be specified, and none are printed.
   Bodies are not indented, and the
   .Fl width
   argument is ignored.
   .It Fl ohang
   Item bodies start on the line following item heads and are not indented.
   The
   .Fl width
   argument is ignored.
   .It Fl tag
   Item bodies are indented according to the
   .Fl width
   argument.
   When an item head fits inside the indentation, the item body follows
   this head on the same output line.
   Otherwise, the body starts on the output line following the head.
   .El
   .Pp
   Lists may be nested within lists and displays.
   Nesting of
   .Fl column
   and
   .Fl enum
   lists may not be portable.
   .Pp
   See also
   .Sx \&El
   and
   .Sx \&It .
   .Ss \&Bo
   Begin a block enclosed by square brackets.
   Does not have any head arguments.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Bo 1 ,
   \&.Dv BUFSIZ \&Bc
 .Ed  .Ed
 .\"  .Pp
 .Sh MACROS  See also
 This section contains a complete list of all  .Sx \&Bq .
   .Ss \&Bq
   Encloses its arguments in square brackets.
   .Pp
   Examples:
   .Dl \&.Bq 1 , \&Dv BUFSIZ
   .Pp
   .Em Remarks :
   this macro is sometimes abused to emulate optional arguments for
   commands; the correct macros to use for this purpose are
   .Sx \&Op ,
   .Sx \&Oo ,
   and
   .Sx \&Oc .
   .Pp
   See also
   .Sx \&Bo .
   .Ss \&Brc
   Close a
   .Sx \&Bro
   block.
   Does not have any tail arguments.
   .Ss \&Bro
   Begin a block enclosed by curly braces.
   Does not have any head arguments.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Bro 1 , ... ,
   \&.Va n \&Brc
   .Ed
   .Pp
   See also
   .Sx \&Brq .
   .Ss \&Brq
   Encloses its arguments in curly braces.
   .Pp
   Examples:
   .Dl \&.Brq 1 , ... , \&Va n
   .Pp
   See also
   .Sx \&Bro .
   .Ss \&Bsx
   Format the BSD/OS version provided as an argument, or a default value if
   no argument is provided.
   .Pp
   Examples:
   .Dl \&.Bsx 1.0
   .Dl \&.Bsx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .Ss \&Bt
   Prints
   .Dq is currently in beta test.
   .Ss \&Bx
   Format the BSD version provided as an argument, or a default value if no
   argument is provided.
   .Pp
   Examples:
   .Dl \&.Bx 4.3 Tahoe
   .Dl \&.Bx 4.4
   .Dl \&.Bx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .Ss \&Cd
   Kernel configuration declaration.
   This denotes strings accepted by
   .Xr config 8 .
   It is most often used in section 4 manual pages.
   .Pp
   Examples:
   .Dl \&.Cd device le0 at scode?
   .Pp
   .Em Remarks :
   this macro is commonly abused by using quoted literals to retain
   whitespace and align consecutive
   .Sx \&Cd
   declarations.
   This practise is discouraged.
   .Ss \&Cm
   Command modifiers.
   Typically used for fixed strings passed as arguments, unless
   .Sx \&Fl
   is more appropriate.
   Also useful when specifying configuration options or keys.
   .Pp
   Examples:
   .Dl ".Nm mt Fl f Ar device Cm rewind"
   .Dl ".Nm ps Fl o Cm pid , Ns Cm command"
   .Dl ".Nm dd Cm if= Ns Ar file1 Cm of= Ns Ar file2"
   .Dl ".Cm IdentityFile Pa ~/.ssh/id_rsa"
   .Dl ".Cm LogLevel Dv DEBUG"
   .Ss \&D1
   One-line indented display.
   This is formatted by the default rules and is useful for simple indented
   statements.
   It is followed by a newline.
   .Pp
   Examples:
   .Dl \&.D1 \&Fl abcdefgh
   .Pp
   See also
   .Sx \&Bd
   and
   .Sx \&Dl .
   .Ss \&Db
   Switch debugging mode.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Db Cm on | off
   .Pp
   This macro is ignored by
   .Xr mandoc 1 .
   .Ss \&Dc
   Close a
   .Sx \&Do
   block.
   Does not have any tail arguments.
   .Ss \&Dd
   Document date.
   This is the mandatory first macro of any
 .Nm  .Nm
 macros, arranged ontologically.  A  manual.
 .Qq callable  Its syntax is as follows:
 macro is invoked subsequent to the initial macro-line macro.  A  
 .Qq parsable  
 macro may be followed by further (ostensibly callable) macros.  
 .\" SUB-SECTION  
 .Ss Block full-implicit  
 The head of these macros follows invocation; the body is the content of  
 subsequent lines prior to closure.  None of these macros have tails;  
 some  
 .Po  
 .Sq \&.It \-bullet ,  
 .Sq \-hyphen ,  
 .Sq \-dash ,  
 .Sq \-enum ,  
 .Sq \-item  
 .Pc  
 don't have heads.  
 .Pp  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" "Closing" -compact -offset XXXX  .D1 Pf \. Sx \&Dd Ar month day , year
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Closing  
 .It \&.Sh    Ta    \&No    Ta    \&No    Ta    \&.Sh  
 .It \&.Ss    Ta    \&No    Ta    \&No    Ta    \&.Sh, \&.Ss  
 .It \&.It    Ta    \&No    Ta    Yes     Ta    \&.It, \&.El  
 .El  
 .\" SUB-SECTION  
 .Ss Block full-explicit  
 None of these macros are callable or parsed.  The last column indicates  
 the explicit scope rules.  All contains bodies, some may contain heads  
 .Pq So \&Bf Sc .  
 .Pp  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" "closed by XXX" -compact -offset XXXX  The
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  .Ar month
 .It \&.Bd    Ta    \&No    Ta    \&No    Ta    closed by \&.Ed  is the full English month name, the
 .It \&.Ed    Ta    \&No    Ta    \&No    Ta    opened by \&.Bd  .Ar day
 .It \&.Bl    Ta    \&No    Ta    \&No    Ta    closed by \&.El  is an optionally zero-padded numeral, and the
 .It \&.El    Ta    \&No    Ta    \&No    Ta    opened by \&.Bl  .Ar year
 .It \&.Bf    Ta    \&No    Ta    \&No    Ta    closed by \&.Ef  is the full four-digit year.
 .It \&.Ef    Ta    \&No    Ta    \&No    Ta    opened by \&.Bf  .Pp
 .It \&.Bk    Ta    \&No    Ta    \&No    Ta    closed by \&.Ek  Other arguments are not portable; the
 .It \&.Ek    Ta    \&No    Ta    \&No    Ta    opened by \&.Bk  .Xr mandoc 1
   utility handles them as follows:
   .Bl -dash -offset 3n -compact
   .It
   To have the date automatically filled in by the
   .Ox
   version of
   .Xr cvs 1 ,
   the special string
   .Dq $\&Mdocdate$
   can be given as an argument.
   .It
   A few alternative date formats are accepted as well
   and converted to the standard form.
   .It
   If a date string cannot be parsed, it is used verbatim.
   .It
   If no date string is given, the current date is used.
 .El  .El
 .\" SUB-SECTION  
 .Ss Block partial-implicit  
 All of these are callable and parsed for further macros.  Their scopes  
 close at the invocation's end-of-line.  
 .Pp  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" -compact -offset XXXX  Examples:
 .It Em Macro Ta Em Callable Ta Em Parsable  .Dl \&.Dd $\&Mdocdate$
 .It \&.Aq    Ta    Yes   Ta    Yes  .Dl \&.Dd $\&Mdocdate: July 21 2007$
 .It \&.Op    Ta    Yes   Ta    Yes  .Dl \&.Dd July 21, 2007
 .It \&.Bq    Ta    Yes   Ta    Yes  .Pp
 .It \&.Dq    Ta    Yes   Ta    Yes  See also
 .It \&.Pq    Ta    Yes   Ta    Yes  .Sx \&Dt
 .It \&.Qq    Ta    Yes   Ta    Yes  and
 .It \&.Sq    Ta    Yes   Ta    Yes  .Sx \&Os .
 .It \&.Brq   Ta    Yes   Ta    Yes  .Ss \&Dl
 .It \&.D1    Ta    \&No  Ta    \&Yes  One-line intended display.
 .It \&.Dl    Ta    \&No  Ta    Yes  This is formatted as literal text and is useful for commands and
 .It \&.Ql    Ta    Yes   Ta    Yes  invocations.
   It is followed by a newline.
   .Pp
   Examples:
   .Dl \&.Dl % mandoc mdoc.7 \e(ba less
   .Pp
   See also
   .Sx \&Bd
   and
   .Sx \&D1 .
   .Ss \&Do
   Begin a block enclosed by double quotes.
   Does not have any head arguments.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Do
   April is the cruellest month
   \&.Dc
   \e(em T.S. Eliot
   .Ed
   .Pp
   See also
   .Sx \&Dq .
   .Ss \&Dq
   Encloses its arguments in
   .Dq typographic
   double-quotes.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Dq April is the cruellest month
   \e(em T.S. Eliot
   .Ed
   .Pp
   See also
   .Sx \&Qq ,
   .Sx \&Sq ,
   and
   .Sx \&Do .
   .Ss \&Dt
   Document title.
   This is the mandatory second macro of any
   .Nm
   file.
   Its syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Dt
   .Oo
   .Ar title
   .Oo
   .Ar section
   .Op Ar volume | arch
   .Oc
   .Oc
   .Ed
   .Pp
   Its arguments are as follows:
   .Bl -tag -width Ds -offset Ds
   .It Ar title
   The document's title (name), defaulting to
   .Dq UNKNOWN
   if unspecified.
   It should be capitalised.
   .It Ar section
   The manual section.
   This may be one of
   .Ar 1
   .Pq utilities ,
   .Ar 2
   .Pq system calls ,
   .Ar 3
   .Pq libraries ,
   .Ar 3p
   .Pq Perl libraries ,
   .Ar 4
   .Pq devices ,
   .Ar 5
   .Pq file formats ,
   .Ar 6
   .Pq games ,
   .Ar 7
   .Pq miscellaneous ,
   .Ar 8
   .Pq system utilities ,
   .Ar 9
   .Pq kernel functions ,
   .Ar X11
   .Pq X Window System ,
   .Ar X11R6
   .Pq X Window System ,
   .Ar unass
   .Pq unassociated ,
   .Ar local
   .Pq local system ,
   .Ar draft
   .Pq draft manual ,
   or
   .Ar paper
   .Pq paper .
   It should correspond to the manual's filename suffix and defaults to
   .Dq 1
   if unspecified.
   .It Ar volume
   This overrides the volume inferred from
   .Ar section .
   This field is optional, and if specified, must be one of
   .Ar USD
   .Pq users' supplementary documents ,
   .Ar PS1
   .Pq programmers' supplementary documents ,
   .Ar AMD
   .Pq administrators' supplementary documents ,
   .Ar SMM
   .Pq system managers' manuals ,
   .Ar URM
   .Pq users' reference manuals ,
   .Ar PRM
   .Pq programmers' reference manuals ,
   .Ar KM
   .Pq kernel manuals ,
   .Ar IND
   .Pq master index ,
   .Ar MMI
   .Pq master index ,
   .Ar LOCAL
   .Pq local manuals ,
   .Ar LOC
   .Pq local manuals ,
   or
   .Ar CON
   .Pq contributed manuals .
   .It Ar arch
   This specifies a specific relevant architecture.
   If
   .Ar volume
   is not provided, it may be used in its place, else it may be used
   subsequent that.
   It, too, is optional.
   It must be one of
   .Ar alpha ,
   .Ar amd64 ,
   .Ar amiga ,
   .Ar arc ,
   .Ar arm ,
   .Ar armish ,
   .Ar aviion ,
   .Ar hp300 ,
   .Ar hppa ,
   .Ar hppa64 ,
   .Ar i386 ,
   .Ar landisk ,
   .Ar loongson ,
   .Ar luna88k ,
   .Ar mac68k ,
   .Ar macppc ,
   .Ar mips64 ,
   .Ar mvme68k ,
   .Ar mvme88k ,
   .Ar mvmeppc ,
   .Ar pmax ,
   .Ar sgi ,
   .Ar socppc ,
   .Ar sparc ,
   .Ar sparc64 ,
   .Ar sun3 ,
   .Ar vax ,
   or
   .Ar zaurus .
 .El  .El
 .\" PARAGRAPH  
 .Pp  .Pp
   Examples:
   .Dl \&.Dt FOO 1
   .Dl \&.Dt FOO 4 KM
   .Dl \&.Dt FOO 9 i386
   .Pp
   See also
   .Sx \&Dd
   and
   .Sx \&Os .
   .Ss \&Dv
   Defined variables such as preprocessor constants, constant symbols,
   enumeration values, and so on.
   .Pp
   Examples:
   .Dl \&.Dv NULL
   .Dl \&.Dv BUFSIZ
   .Dl \&.Dv STDOUT_FILENO
   .Pp
   See also
   .Sx \&Er
   and
   .Sx \&Ev
   for special-purpose constants and
   .Sx \&Va
   for variable symbols.
   .Ss \&Dx
   Format the DragonFly BSD version provided as an argument, or a default
   value if no argument is provided.
   .Pp
   Examples:
   .Dl \&.Dx 2.4.1
   .Dl \&.Dx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .Ss \&Ec
   Close a scope started by
   .Sx \&Eo .
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Ec Op Ar TERM
   .Pp
 The  The
 .Sq \&.Op  .Ar TERM
 may be broken by  argument is used as the enclosure tail, for example, specifying \e(rq
 .Sq \&.Oc  will emulate
 as in the following example:  .Sx \&Dc .
 .Bd -literal -offset XXXX  .Ss \&Ed
   End a display context started by
   .Sx \&Bd .
   .Ss \&Ef
   End a font mode context started by
   .Sx \&Bf .
   .Ss \&Ek
   End a keep context started by
   .Sx \&Bk .
   .Ss \&El
   End a list context started by
   .Sx \&Bl .
   .Pp
   See also
   .Sx \&Bl
   and
   .Sx \&It .
   .Ss \&Em
   Denotes text that should be
   .Em emphasised .
   Note that this is a presentation term and should not be used for
   stylistically decorating technical terms.
   Depending on the output device, this is usually represented
   using an italic font or underlined characters.
   .Pp
   Examples:
   .Dl \&.Em Warnings!
   .Dl \&.Em Remarks :
   .Pp
   See also
   .Sx \&Bf ,
   .Sx \&Li ,
   .Sx \&No ,
   and
   .Sx \&Sy .
   .Ss \&En
   This macro is obsolete and not implemented in
   .Xr mandoc 1 .
   .Ss \&Eo
   An arbitrary enclosure.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Eo Op Ar TERM
   .Pp
   The
   .Ar TERM
   argument is used as the enclosure head, for example, specifying \e(lq
   will emulate
   .Sx \&Do .
   .Ss \&Er
   Error constants for definitions of the
   .Va errno
   libc global variable.
   This is most often used in section 2 and 3 manual pages.
   .Pp
   Examples:
   .Dl \&.Er EPERM
   .Dl \&.Er ENOENT
   .Pp
   See also
   .Sx \&Dv
   for general constants.
   .Ss \&Es
   This macro is obsolete and not implemented.
   .Ss \&Ev
   Environmental variables such as those specified in
   .Xr environ 7 .
   .Pp
   Examples:
   .Dl \&.Ev DISPLAY
   .Dl \&.Ev PATH
   .Pp
   See also
   .Sx \&Dv
   for general constants.
   .Ss \&Ex
   Insert a standard sentence regarding command exit values of 0 on success
   and >0 on failure.
   This is most often used in section 1, 6, and 8 manual pages.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Ex Fl std Op Ar utility ...
   .Pp
   If
   .Ar utility
   is not specified, the document's name set by
   .Sx \&Nm
   is used.
   Multiple
   .Ar utility
   arguments are treated as separate utilities.
   .Pp
   See also
   .Sx \&Rv .
   .Ss \&Fa
   Function argument.
   Its syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Fa
   .Op Cm argtype
   .Cm argname
   .Ed
   .Pp
   This may be invoked for names with or without the corresponding type.
   It is also used to specify the field name of a structure.
   Most often, the
   .Sx \&Fa
   macro is used in the
   .Em SYNOPSIS
   within
   .Sx \&Fo
   section when documenting multi-line function prototypes.
   If invoked with multiple arguments, the arguments are separated by a
   comma.
   Furthermore, if the following macro is another
   .Sx \&Fa ,
   the last argument will also have a trailing comma.
   .Pp
   Examples:
   .Dl \&.Fa \(dqconst char *p\(dq
   .Dl \&.Fa \(dqint a\(dq \(dqint b\(dq \(dqint c\(dq
   .Dl \&.Fa foo
   .Pp
   See also
   .Sx \&Fo .
   .Ss \&Fc
   End a function context started by
   .Sx \&Fo .
   .Ss \&Fd
   Historically used to document include files.
   This usage has been deprecated in favour of
   .Sx \&In .
   Do not use this macro.
   .Pp
   See also
   .Sx MANUAL STRUCTURE
   and
   .Sx \&In .
   .Ss \&Fl
   Command-line flag or option.
   Used when listing arguments to command-line utilities.
   Prints a fixed-width hyphen
   .Sq \-
   directly followed by each argument.
   If no arguments are provided, a hyphen is printed followed by a space.
   If the argument is a macro, a hyphen is prefixed to the subsequent macro
   output.
   .Pp
   Examples:
   .Dl ".Fl R Op Fl H | L | P"
   .Dl ".Op Fl 1AaCcdFfgHhikLlmnopqRrSsTtux"
   .Dl ".Fl type Cm d Fl name Pa CVS"
   .Dl ".Fl Ar signal_number"
   .Dl ".Fl o Fl"
   .Pp
   See also
   .Sx \&Cm .
   .Ss \&Fn
   A function name.
   Its syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Ns Sx \&Fn
   .Op Ar functype
   .Ar funcname
   .Op Oo Ar argtype Oc Ar argname
   .Ed
   .Pp
   Function arguments are surrounded in parenthesis and
   are delimited by commas.
   If no arguments are specified, blank parenthesis are output.
   In the
   .Em SYNOPSIS
   section, this macro starts a new output line,
   and a blank line is automatically inserted between function definitions.
   .Pp
   Examples:
   .Dl \&.Fn \(dqint funcname\(dq \(dqint arg0\(dq \(dqint arg1\(dq
   .Dl \&.Fn funcname \(dqint arg0\(dq
   .Dl \&.Fn funcname arg0
   .Pp
   .Bd -literal -offset indent -compact
   \&.Ft functype
   \&.Fn funcname
   .Ed
   .Pp
   When referring to a function documented in another manual page, use
   .Sx \&Xr
   instead.
   See also
   .Sx MANUAL STRUCTURE ,
   .Sx \&Fo ,
   and
   .Sx \&Ft .
   .Ss \&Fo
   Begin a function block.
   This is a multi-line version of
   .Sx \&Fn .
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Fo Ar funcname
   .Pp
   Invocations usually occur in the following context:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Ft Ar functype
   .br
   .Pf \. Sx \&Fo Ar funcname
   .br
   .Pf \. Sx \&Fa Oo Ar argtype Oc Ar argname
   .br
   \&.\.\.
   .br
   .Pf \. Sx \&Fc
   .Ed
   .Pp
   A
   .Sx \&Fo
   scope is closed by
   .Sx \&Fc .
   .Pp
   See also
   .Sx MANUAL STRUCTURE ,
   .Sx \&Fa ,
   .Sx \&Fc ,
   and
   .Sx \&Ft .
   .Ss \&Fr
   This macro is obsolete and not implemented in
   .Xr mandoc 1 .
   .Pp
   It was used to show function return values.
   The syntax was:
   .Pp
   .Dl Pf . Sx \&Fr Ar value
   .Ss \&Ft
   A function type.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Ft Ar functype
   .Pp
   In the
   .Em SYNOPSIS
   section, a new output line is started after this macro.
   .Pp
   Examples:
   .Dl \&.Ft int
   .Bd -literal -offset indent -compact
   \&.Ft functype
   \&.Fn funcname
   .Ed
   .Pp
   See also
   .Sx MANUAL STRUCTURE ,
   .Sx \&Fn ,
   and
   .Sx \&Fo .
   .Ss \&Fx
   Format the
   .Fx
   version provided as an argument, or a default value
   if no argument is provided.
   .Pp
   Examples:
   .Dl \&.Fx 7.1
   .Dl \&.Fx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .Ss \&Hf
   This macro is not implemented in
   .Xr mandoc 1 .
   .Pp
   It was used to include the contents of a (header) file literally.
   The syntax was:
   .Pp
   .Dl Pf . Sx \&Hf Ar filename
   .Ss \&Ic
   Designate an internal or interactive command.
   This is similar to
   .Sx \&Cm
   but used for instructions rather than values.
   .Pp
   Examples:
   .Dl \&.Ic :wq
   .Dl \&.Ic hash
   .Dl \&.Ic alias
   .Pp
   Note that using
   .Sx \&Bd Fl literal
   or
   .Sx \&D1
   is preferred for displaying code; the
   .Sx \&Ic
   macro is used when referring to specific instructions.
   .Ss \&In
   An
   .Dq include
   file.
   When invoked as the first macro on an input line in the
   .Em SYNOPSIS
   section, the argument is displayed in angle brackets
   and preceded by
   .Dq #include ,
   and a blank line is inserted in front if there is a preceding
   function declaration.
   This is most often used in section 2, 3, and 9 manual pages.
   .Pp
   Examples:
   .Dl \&.In sys/types.h
   .Pp
   See also
   .Sx MANUAL STRUCTURE .
   .Ss \&It
   A list item.
   The syntax of this macro depends on the list type.
   .Pp
   Lists
   of type
   .Fl hang ,
   .Fl ohang ,
   .Fl inset ,
   and
   .Fl diag
   have the following syntax:
   .Pp
   .D1 Pf \. Sx \&It Ar args
   .Pp
   Lists of type
   .Fl bullet ,
   .Fl dash ,
   .Fl enum ,
   .Fl hyphen
   and
   .Fl item
   have the following syntax:
   .Pp
   .D1 Pf \. Sx \&It
   .Pp
   with subsequent lines interpreted within the scope of the
   .Sx \&It
   until either a closing
   .Sx \&El
   or another
   .Sx \&It .
   .Pp
   The
   .Fl tag
   list has the following syntax:
   .Pp
   .D1 Pf \. Sx \&It Op Cm args
   .Pp
   Subsequent lines are interpreted as with
   .Fl bullet
   and family.
   The line arguments correspond to the list's left-hand side; body
   arguments correspond to the list's contents.
   .Pp
   The
   .Fl column
   list is the most complicated.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&It Ar cell Op <TAB> Ar cell ...
   .D1 Pf \. Sx \&It Ar cell Op Sx \&Ta Ar cell ...
   .Pp
   The arguments consist of one or more lines of text and macros
   representing a complete table line.
   Cells within the line are delimited by tabs or by the special
   .Sx \&Ta
   block macro.
   The tab cell delimiter may only be used within the
   .Sx \&It
   line itself; on following lines, only the
   .Sx \&Ta
   macro can be used to delimit cells, and
   .Sx \&Ta
   is only recognised as a macro when called by other macros,
   not as the first macro on a line.
   .Pp
   Note that quoted strings may span tab-delimited cells on an
   .Sx \&It
   line.
   For example,
   .Pp
   .Dl .It \(dqcol1 ; <TAB> col2 ;\(dq \&;
   .Pp
   will preserve the semicolon whitespace except for the last.
   .Pp
   See also
   .Sx \&Bl .
   .Ss \&Lb
   Specify a library.
   The syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Lb Ar library
   .Pp
   The
   .Ar library
   parameter may be a system library, such as
   .Cm libz
   or
   .Cm libpam ,
   in which case a small library description is printed next to the linker
   invocation; or a custom library, in which case the library name is
   printed in quotes.
   This is most commonly used in the
   .Em SYNOPSIS
   section as described in
   .Sx MANUAL STRUCTURE .
   .Pp
   Examples:
   .Dl \&.Lb libz
   .Dl \&.Lb mdoc
   .Ss \&Li
   Denotes text that should be in a
   .Li literal
   font mode.
   Note that this is a presentation term and should not be used for
   stylistically decorating technical terms.
   .Pp
   On terminal output devices, this is often indistinguishable from
   normal text.
   .Pp
   See also
   .Sx \&Bf ,
   .Sx \&Em ,
   .Sx \&No ,
   and
   .Sx \&Sy .
   .Ss \&Lk
   Format a hyperlink.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Lk Ar uri Op Ar name
   .Pp
   Examples:
   .Dl \&.Lk http://bsd.lv \(dqThe BSD.lv Project\(dq
   .Dl \&.Lk http://bsd.lv
   .Pp
   See also
   .Sx \&Mt .
   .Ss \&Lp
   Synonym for
   .Sx \&Pp .
   .Ss \&Ms
   Display a mathematical symbol.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Ms Ar symbol
   .Pp
   Examples:
   .Dl \&.Ms sigma
   .Dl \&.Ms aleph
   .Ss \&Mt
   Format a
   .Dq mailto:
   hyperlink.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Mt Ar address
   .Pp
   Examples:
   .Dl \&.Mt discuss@manpages.bsd.lv
   .Ss \&Nd
   A one line description of the manual's content.
   This may only be invoked in the
   .Em SYNOPSIS
   section subsequent the
   .Sx \&Nm
   macro.
   .Pp
   Examples:
   .Dl Pf . Sx \&Nd mdoc language reference
   .Dl Pf . Sx \&Nd format and display UNIX manuals
   .Pp
   The
   .Sx \&Nd
   macro technically accepts child macros and terminates with a subsequent
   .Sx \&Sh
   invocation.
   Do not assume this behaviour: some
   .Xr whatis 1
   database generators are not smart enough to parse more than the line
   arguments and will display macros verbatim.
   .Pp
   See also
   .Sx \&Nm .
   .Ss \&Nm
   The name of the manual page, or \(em in particular in section 1, 6,
   and 8 pages \(em of an additional command or feature documented in
   the manual page.
   When first invoked, the
   .Sx \&Nm
   macro expects a single argument, the name of the manual page.
   Usually, the first invocation happens in the
   .Em NAME
   section of the page.
   The specified name will be remembered and used whenever the macro is
   called again without arguments later in the page.
   The
   .Sx \&Nm
   macro uses
   .Sx Block full-implicit
   semantics when invoked as the first macro on an input line in the
   .Em SYNOPSIS
   section; otherwise, it uses ordinary
   .Sx In-line
   semantics.
   .Pp
   Examples:
   .Bd -literal -offset indent
   \&.Sh SYNOPSIS
   \&.Nm cat
   \&.Op Fl benstuv
   \&.Op Ar
   .Ed
   .Pp
   In the
   .Em SYNOPSIS
   of section 2, 3 and 9 manual pages, use the
   .Sx \&Fn
   macro rather than
   .Sx \&Nm
   to mark up the name of the manual page.
   .Ss \&No
   Normal text.
   Closes the scope of any preceding in-line macro.
   When used after physical formatting macros like
   .Sx \&Em
   or
   .Sx \&Sy ,
   switches back to the standard font face and weight.
   Can also be used to embed plain text strings in macro lines
   using semantic annotation macros.
   .Pp
   Examples:
   .Dl ".Em italic , Sy bold , No and roman"
   .Pp
   .Bd -literal -offset indent -compact
   \&.Sm off
   \&.Cm :C No / Ar pattern No / Ar replacement No /
   \&.Sm on
   .Ed
   .Pp
   See also
   .Sx \&Em ,
   .Sx \&Li ,
   and
   .Sx \&Sy .
   .Ss \&Ns
   Suppress a space between the output of the preceding macro
   and the following text or macro.
   Following invocation, input is interpreted as normal text
   just like after an
   .Sx \&No
   macro.
   .Pp
   This has no effect when invoked at the start of a macro line.
   .Pp
   Examples:
   .Dl ".Ar name Ns = Ns Ar value"
   .Dl ".Cm :M Ns Ar pattern"
   .Dl ".Fl o Ns Ar output"
   .Pp
   See also
   .Sx \&No
   and
   .Sx \&Sm .
   .Ss \&Nx
   Format the
   .Nx
   version provided as an argument, or a default value if
   no argument is provided.
   .Pp
   Examples:
   .Dl \&.Nx 5.01
   .Dl \&.Nx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .Ss \&Oc
   Close multi-line
   .Sx \&Oo
   context.
   .Ss \&Oo
   Multi-line version of
   .Sx \&Op .
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
 \&.Oo  \&.Oo
 \&.Op Fl a Oc  \&.Op Fl flag Ns Ar value
   \&.Oc
 .Ed  .Ed
   .Ss \&Op
   Optional part of a command line.
   Prints the argument(s) in brackets.
   This is most often used in the
   .Em SYNOPSIS
   section of section 1 and 8 manual pages.
 .Pp  .Pp
 In the above example, the scope of  Examples:
 .Sq \&.Op  .Dl \&.Op \&Fl a \&Ar b
 is technically broken by  .Dl \&.Op \&Ar a | b
 .Sq \&.Oc ,  
 however, due to the overwhelming existence of this sequence, it's  
 allowed.  
 .\" SUB-SECTION  
 .Ss Block partial-explicit  
 Each of these contains at least a body and, in limited circumstances, a  
 head  
 .Pq So \&.Fo Sc , So \&.Eo Sc  
 and/or tail  
 .Pq So \&.Ec Sc .  
 .Pp  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" "closed by XXXX" -compact -offset XXXX  See also
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  .Sx \&Oo .
 .It \&.Ao    Ta    Yes   Ta    Yes    Ta    closed by \&.Ac  .Ss \&Os
 .It \&.Ac    Ta    Yes   Ta    Yes    Ta    opened by \&.Ao  Document operating system version.
 .It \&.Bc    Ta    Yes   Ta    Yes    Ta    closed by \&.Bo  This is the mandatory third macro of
 .It \&.Bo    Ta    Yes   Ta    Yes    Ta    opened by \&.Bc  any
 .It \&.Pc    Ta    Yes   Ta    Yes    Ta    closed by \&.Po  .Nm
 .It \&.Po    Ta    Yes   Ta    Yes    Ta    opened by \&.Pc  file.
 .It \&.Do    Ta    Yes   Ta    Yes    Ta    closed by \&.Dc  Its syntax is as follows:
 .It \&.Dc    Ta    Yes   Ta    Yes    Ta    opened by \&.Do  
 .It \&.Xo    Ta    Yes   Ta    Yes    Ta    closed by \&.Xc  
 .It \&.Xc    Ta    Yes   Ta    Yes    Ta    opened by \&.Xo  
 .It \&.Bro   Ta    Yes   Ta    Yes    Ta    closed by \&.Brc  
 .It \&.Brc   Ta    Yes   Ta    Yes    Ta    opened by \&.Bro  
 .It \&.Oc    Ta    Yes   Ta    Yes    Ta    closed by \&.Oo  
 .It \&.Oo    Ta    Yes   Ta    Yes    Ta    opened by \&.Oc  
 .It \&.So    Ta    Yes   Ta    Yes    Ta    closed by \&.Sc  
 .It \&.Sc    Ta    Yes   Ta    Yes    Ta    opened by \&.So  
 .It \&.Fc    Ta    Yes   Ta    Yes    Ta    opened by \&.Fo  
 .It \&.Fo    Ta    \&No  Ta    \&No   Ta    closed by \&.Fc  
 .It \&.Ec    Ta    Yes   Ta    Yes    Ta    opened by \&.Eo  
 .It \&.Eo    Ta    Yes   Ta    Yes    Ta    closed by \&.Ec  
 .It \&.Qc    Ta    Yes   Ta    Yes    Ta    opened by \&.Oo  
 .It \&.Qo    Ta    Yes   Ta    Yes    Ta    closed by \&.Oc  
 .It \&.Re    Ta    \&No  Ta    \&No   Ta    opened by \&.Rs  
 .It \&.Rs    Ta    \&No  Ta    \&No   Ta    closed by \&.Re  
 .El  
 .\" SUB-SECTION  
 .Ss In-line  
 In-line macros have only text children.  If a number (or inequality) of  
 arguments is  
 .Pq n ,  
 then the macro accepts an arbitrary number of arguments.  
 .Pp  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" "Arguments" -compact -offset XXXX  .D1 Pf \. Sx \&Os Op Ar system Op Ar version
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Arguments  .Pp
 .It \&.Dd    Ta    \&No  Ta    \&No    Ta    >0  The optional
 .It \&.Dt    Ta    \&No  Ta    \&No    Ta    n  .Ar system
 .It \&.Os    Ta    \&No  Ta    \&No    Ta    n  parameter specifies the relevant operating system or environment.
 .It \&.Pp    Ta    \&No  Ta    \&No    Ta    0  Left unspecified, it defaults to the local operating system version.
 .It \&.Ad    Ta    Yes   Ta    Yes     Ta    n  This is the suggested form.
 .It \&.An    Ta    \&No  Ta    Yes     Ta    n  .Pp
 .It \&.Ar    Ta    Yes   Ta    Yes     Ta    n  Examples:
 .It \&.Cd    Ta    Yes   Ta    \&No    Ta    >0  .Dl \&.Os
 .It \&.Cm    Ta    Yes   Ta    Yes     Ta    n  .Dl \&.Os KTH/CSC/TCS
 .It \&.Dv    Ta    Yes   Ta    Yes     Ta    n  .Dl \&.Os BSD 4.3
 .It \&.Er    Ta    Yes   Ta    Yes     Ta    >0  .Pp
 .It \&.Ev    Ta    Yes   Ta    Yes     Ta    n  See also
 .It \&.Ex    Ta    \&No  Ta    \&No    Ta    0  .Sx \&Dd
 .It \&.Fa    Ta    Yes   Ta    Yes     Ta    n  and
 .It \&.Fd    Ta    \&No  Ta    \&No    Ta    >0  .Sx \&Dt .
 .It \&.Fl    Ta    Yes   Ta    Yes     Ta    n  .Ss \&Ot
 .It \&.Fn    Ta    Yes   Ta    Yes     Ta    >0  This macro is obsolete and not implemented in
 .It \&.Ft    Ta    \&No  Ta    Yes     Ta    n  .Xr mandoc 1 .
 .It \&.Ic    Ta    Yes   Ta    Yes     Ta    >0  .Pp
 .It \&.In    Ta    \&No  Ta    \&No    Ta    n  Historical
 .It \&.Li    Ta    Yes   Ta    Yes     Ta    n  .Xr mdoc 7
 .It \&.Nd    Ta    \&No  Ta    \&No    Ta    n  packages described it as
 .It \&.Nm    Ta    Yes   Ta    Yes     Ta    n  .Dq "old function type (FORTRAN)" .
 .It \&.Ot    Ta    \&No  Ta    \&No    Ta    n  .Ss \&Ox
 .It \&.Pa    Ta    Yes   Ta    Yes     Ta    n  Format the
 .It \&.Rv    Ta    \&No  Ta    \&No    Ta    0  .Ox
 .It \&.St    Ta    \&No  Ta    Yes     Ta    1  version provided as an argument, or a default value
 .It \&.Va    Ta    Yes   Ta    Yes     Ta    n  if no argument is provided.
 .It \&.Vt    Ta    Yes   Ta    Yes     Ta    >0  .Pp
 .It \&.Xr    Ta    Yes   Ta    Yes     Ta    >0, <3  Examples:
 .It \&.%A    Ta    \&No  Ta    \&No    Ta    >0  .Dl \&.Ox 4.5
 .It \&.%B    Ta    \&No  Ta    \&No    Ta    >0  .Dl \&.Ox
 .It \&.%C    Ta    \&No  Ta    \&No    Ta    >0  .Pp
 .It \&.%D    Ta    \&No  Ta    \&No    Ta    >0  See also
 .It \&.%I    Ta    \&No  Ta    \&No    Ta    >0  .Sx \&At ,
 .It \&.%J    Ta    \&No  Ta    \&No    Ta    >0  .Sx \&Bsx ,
 .It \&.%N    Ta    \&No  Ta    \&No    Ta    >0  .Sx \&Bx ,
 .It \&.%O    Ta    \&No  Ta    \&No    Ta    >0  .Sx \&Dx ,
 .It \&.%P    Ta    \&No  Ta    \&No    Ta    >0  .Sx \&Fx ,
 .It \&.%R    Ta    \&No  Ta    \&No    Ta    >0  .Sx \&Nx ,
 .It \&.%T    Ta    \&No  Ta    \&No    Ta    >0  and
 .It \&.%V    Ta    \&No  Ta    \&No    Ta    >0  .Sx \&Ux .
 .It \&.At    Ta    Yes   Ta    Yes     Ta    1  .Ss \&Pa
 .It \&.Bsx   Ta    Yes   Ta    Yes     Ta    n  An absolute or relative file system path, or a file or directory name.
 .It \&.Bx    Ta    Yes   Ta    Yes     Ta    n  If an argument is not provided, the character
 .It \&.Db    Ta    \&No  Ta    \&No    Ta    1  .Sq \(ti
 .It \&.Em    Ta    Yes   Ta    Yes     Ta    >0  is used as a default.
 .It \&.Fx    Ta    Yes   Ta    Yes     Ta    n  .Pp
 .It \&.Ms    Ta    \&No  Ta    Yes     Ta    >0  Examples:
 .It \&.No    Ta    Yes   Ta    Yes     Ta    0  .Dl \&.Pa /usr/bin/mandoc
 .It \&.Ns    Ta    Yes   Ta    Yes     Ta    0  .Dl \&.Pa /usr/share/man/man7/mdoc.7
 .It \&.Nx    Ta    Yes   Ta    Yes     Ta    n  .Pp
 .It \&.Ox    Ta    Yes   Ta    Yes     Ta    n  See also
 .It \&.Pf    Ta    \&No  Ta    Yes     Ta    1  .Sx \&Lk .
 .It \&.Sm    Ta    \&No  Ta    \&No    Ta    1  .Ss \&Pc
 .It \&.Sx    Ta    Yes   Ta    Yes     Ta    >0  Close parenthesised context opened by
 .It \&.Sy    Ta    Yes   Ta    Yes     Ta    >0  .Sx \&Po .
 .It \&.Tn    Ta    Yes   Ta    Yes     Ta    >0  .Ss \&Pf
 .It \&.Ux    Ta    Yes   Ta    Yes     Ta    n  Removes the space between its argument
 .It \&.Dx    Ta    Yes   Ta    Yes     Ta    n  .Pq Dq prefix
 .It \&.Bt    Ta    \&No  Ta    \&No    Ta    0  and the following macro.
 .It \&.Hf    Ta    \&No  Ta    \&No    Ta    n  Its syntax is as follows:
 .It \&.Fr    Ta    \&No  Ta    \&No    Ta    n  .Pp
 .It \&.Ud    Ta    \&No  Ta    \&No    Ta    0  .D1 .Pf Ar prefix macro arguments ...
 .It \&.Lb    Ta    \&No  Ta    \&No    Ta    1  .Pp
 .It \&.Ap    Ta    Yes   Ta    Yes     Ta    0  This is equivalent to:
 .It \&.Lp    Ta    \&No  Ta    \&No    Ta    0  .Pp
 .It \&.Lk    Ta    \&No  Ta    Yes     Ta    >0  .D1 .No Ar prefix No \&Ns Ar macro arguments ...
 .It \&.Mt    Ta    \&No  Ta    Yes     Ta    >0  .Pp
 .It \&.Es    Ta    \&No  Ta    \&No    Ta    0  Examples:
 .It \&.En    Ta    \&No  Ta    \&No    Ta    0  .Dl ".Pf $ Ar variable_name"
   .Dl ".Pf 0x Ar hex_digits"
   .Pp
   See also
   .Sx \&Ns
   and
   .Sx \&Sm .
   .Ss \&Po
   Multi-line version of
   .Sx \&Pq .
   .Ss \&Pp
   Break a paragraph.
   This will assert vertical space between prior and subsequent macros
   and/or text.
   .Pp
   Paragraph breaks are not needed before or after
   .Sx \&Sh
   or
   .Sx \&Ss
   macros or before displays
   .Pq Sx \&Bd
   or lists
   .Pq Sx \&Bl
   unless the
   .Fl compact
   flag is given.
   .Ss \&Pq
   Parenthesised enclosure.
   .Pp
   See also
   .Sx \&Po .
   .Ss \&Qc
   Close quoted context opened by
   .Sx \&Qo .
   .Ss \&Ql
   Format a single-quoted literal.
   See also
   .Sx \&Qq
   and
   .Sx \&Sq .
   .Ss \&Qo
   Multi-line version of
   .Sx \&Qq .
   .Ss \&Qq
   Encloses its arguments in
   .Qq typewriter
   double-quotes.
   Consider using
   .Sx \&Dq .
   .Pp
   See also
   .Sx \&Dq ,
   .Sx \&Sq ,
   and
   .Sx \&Qo .
   .Ss \&Re
   Close an
   .Sx \&Rs
   block.
   Does not have any tail arguments.
   .Ss \&Rs
   Begin a bibliographic
   .Pq Dq reference
   block.
   Does not have any head arguments.
   The block macro may only contain
   .Sx \&%A ,
   .Sx \&%B ,
   .Sx \&%C ,
   .Sx \&%D ,
   .Sx \&%I ,
   .Sx \&%J ,
   .Sx \&%N ,
   .Sx \&%O ,
   .Sx \&%P ,
   .Sx \&%Q ,
   .Sx \&%R ,
   .Sx \&%T ,
   .Sx \&%U ,
   and
   .Sx \&%V
   child macros (at least one must be specified).
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Rs
   \&.%A J. E. Hopcroft
   \&.%A J. D. Ullman
   \&.%B Introduction to Automata Theory, Languages, and Computation
   \&.%I Addison-Wesley
   \&.%C Reading, Massachusettes
   \&.%D 1979
   \&.Re
   .Ed
   .Pp
   If an
   .Sx \&Rs
   block is used within a SEE ALSO section, a vertical space is asserted
   before the rendered output, else the block continues on the current
   line.
   .Ss \&Rv
   Insert a standard sentence regarding a function call's return value of 0
   on success and \-1 on error, with the
   .Va errno
   libc global variable set on error.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Rv Fl std Op Ar function ...
   .Pp
   If
   .Ar function
   is not specified, the document's name set by
   .Sx \&Nm
   is used.
   Multiple
   .Ar function
   arguments are treated as separate functions.
   .Pp
   See also
   .Sx \&Ex .
   .Ss \&Sc
   Close single-quoted context opened by
   .Sx \&So .
   .Ss \&Sh
   Begin a new section.
   For a list of conventional manual sections, see
   .Sx MANUAL STRUCTURE .
   These sections should be used unless it's absolutely necessary that
   custom sections be used.
   .Pp
   Section names should be unique so that they may be keyed by
   .Sx \&Sx .
   Although this macro is parsed, it should not consist of child node or it
   may not be linked with
   .Sx \&Sx .
   .Pp
   See also
   .Sx \&Pp ,
   .Sx \&Ss ,
   and
   .Sx \&Sx .
   .Ss \&Sm
   Switches the spacing mode for output generated from macros.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Sm Cm on | off
   .Pp
   By default, spacing is
   .Cm on .
   When switched
   .Cm off ,
   no white space is inserted between macro arguments and between the
   output generated from adjacent macros, but text lines
   still get normal spacing between words and sentences.
   .Ss \&So
   Multi-line version of
   .Sx \&Sq .
   .Ss \&Sq
   Encloses its arguments in
   .Sq typewriter
   single-quotes.
   .Pp
   See also
   .Sx \&Dq ,
   .Sx \&Qq ,
   and
   .Sx \&So .
   .Ss \&Ss
   Begin a new subsection.
   Unlike with
   .Sx \&Sh ,
   there is no convention for the naming of subsections.
   Except
   .Em DESCRIPTION ,
   the conventional sections described in
   .Sx MANUAL STRUCTURE
   rarely have subsections.
   .Pp
   Sub-section names should be unique so that they may be keyed by
   .Sx \&Sx .
   Although this macro is parsed, it should not consist of child node or it
   may not be linked with
   .Sx \&Sx .
   .Pp
   See also
   .Sx \&Pp ,
   .Sx \&Sh ,
   and
   .Sx \&Sx .
   .Ss \&St
   Replace an abbreviation for a standard with the full form.
   The following standards are recognised:
   .Pp
   .Bl -tag -width "-p1003.1g-2000X" -compact
   .It \-p1003.1-88
   .St -p1003.1-88
   .It \-p1003.1-90
   .St -p1003.1-90
   .It \-p1003.1-96
   .St -p1003.1-96
   .It \-p1003.1-2001
   .St -p1003.1-2001
   .It \-p1003.1-2004
   .St -p1003.1-2004
   .It \-p1003.1-2008
   .St -p1003.1-2008
   .It \-p1003.1
   .St -p1003.1
   .It \-p1003.1b
   .St -p1003.1b
   .It \-p1003.1b-93
   .St -p1003.1b-93
   .It \-p1003.1c-95
   .St -p1003.1c-95
   .It \-p1003.1g-2000
   .St -p1003.1g-2000
   .It \-p1003.1i-95
   .St -p1003.1i-95
   .It \-p1003.2-92
   .St -p1003.2-92
   .It \-p1003.2a-92
   .St -p1003.2a-92
   .It \-p1387.2-95
   .St -p1387.2-95
   .It \-p1003.2
   .St -p1003.2
   .It \-p1387.2
   .St -p1387.2
   .It \-isoC
   .St -isoC
   .It \-isoC-90
   .St -isoC-90
   .It \-isoC-amd1
   .St -isoC-amd1
   .It \-isoC-tcor1
   .St -isoC-tcor1
   .It \-isoC-tcor2
   .St -isoC-tcor2
   .It \-isoC-99
   .St -isoC-99
   .It \-iso9945-1-90
   .St -iso9945-1-90
   .It \-iso9945-1-96
   .St -iso9945-1-96
   .It \-iso9945-2-93
   .St -iso9945-2-93
   .It \-ansiC
   .St -ansiC
   .It \-ansiC-89
   .St -ansiC-89
   .It \-ansiC-99
   .St -ansiC-99
   .It \-ieee754
   .St -ieee754
   .It \-iso8802-3
   .St -iso8802-3
   .It \-ieee1275-94
   .St -ieee1275-94
   .It \-xpg3
   .St -xpg3
   .It \-xpg4
   .St -xpg4
   .It \-xpg4.2
   .St -xpg4.2
   .It \-xpg4.3
   .St -xpg4.3
   .It \-xbd5
   .St -xbd5
   .It \-xcu5
   .St -xcu5
   .It \-xsh5
   .St -xsh5
   .It \-xns5
   .St -xns5
   .It \-xns5.2
   .St -xns5.2
   .It \-xns5.2d2.0
   .St -xns5.2d2.0
   .It \-xcurses4.2
   .St -xcurses4.2
   .It \-susv2
   .St -susv2
   .It \-susv3
   .St -susv3
   .It \-svid4
   .St -svid4
 .El  .El
   .Ss \&Sx
   Reference a section or subsection in the same manual page.
   The referenced section or subsection name must be identical to the
   enclosed argument, including whitespace.
 .Pp  .Pp
   Examples:
   .Dl \&.Sx MANUAL STRUCTURE
   .Pp
   See also
   .Sx \&Sh
   and
   .Sx \&Ss .
   .Ss \&Sy
   Format enclosed arguments in symbolic
   .Pq Dq boldface .
   Note that this is a presentation term and should not be used for
   stylistically decorating technical terms.
   .Pp
   See also
   .Sx \&Bf ,
   .Sx \&Em ,
   .Sx \&Li ,
   and
   .Sx \&No .
   .Ss \&Ta
   Table cell separator in
   .Sx \&Bl Fl column
   lists; can only be used below
   .Sx \&It .
   .Ss \&Tn
   Format a tradename.
   .Pp
   Since this macro is often implemented to use a small caps font,
   it has historically been used for acronyms (like ASCII) as well.
   Such usage is not recommended because it would use the same macro
   sometimes for semantical annotation, sometimes for physical formatting.
   .Pp
   Examples:
   .Dl \&.Tn IBM
   .Ss \&Ud
   Prints out
   .Dq currently under development.
   .Ss \&Ux
   Format the UNIX name.
   Accepts no argument.
   .Pp
   Examples:
   .Dl \&.Ux
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   and
   .Sx \&Ox .
   .Ss \&Va
   A variable name.
   .Pp
   Examples:
   .Dl \&.Va foo
   .Dl \&.Va const char *bar ;
   .Ss \&Vt
   A variable type.
   This is also used for indicating global variables in the
   .Em SYNOPSIS
   section, in which case a variable name is also specified.
   Note that it accepts
   .Sx Block partial-implicit
   syntax when invoked as the first macro on an input line in the
   .Em SYNOPSIS
   section, else it accepts ordinary
   .Sx In-line
   syntax.
   In the former case, this macro starts a new output line,
   and a blank line is inserted in front if there is a preceding
   function definition or include directive.
   .Pp
   Note that this should not be confused with
   .Sx \&Ft ,
   which is used for function return types.
   .Pp
   Examples:
   .Dl \&.Vt unsigned char
   .Dl \&.Vt extern const char * const sys_signame[] \&;
   .Pp
   See also
   .Sx MANUAL STRUCTURE
   and
   .Sx \&Va .
   .Ss \&Xc
   Close a scope opened by
   .Sx \&Xo .
   .Ss \&Xo
   Extend the header of an
   .Sx \&It
   macro or the body of a partial-implicit block macro
   beyond the end of the input line.
   This macro originally existed to work around the 9-argument limit
   of historic
   .Xr roff 7 .
   .Ss \&Xr
   Link to another manual
   .Pq Qq cross-reference .
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Xr Ar name section
   .Pp
 The  The
 .Sq \&.Ot ,  .Ar name
 .Sq \&.Fr ,  
 .Sq \&.Es  
 and  and
 .Sq \&.En ,  .Ar section
 macros are obsolete.  are the name and section of the linked manual.
 .\" SECTION  If
   .Ar section
   is followed by non-punctuation, an
   .Sx \&Ns
   is inserted into the token stream.
   This behaviour is for compatibility with
   GNU troff.
   .Pp
   Examples:
   .Dl \&.Xr mandoc 1
   .Dl \&.Xr mandoc 1 \&;
   .Dl \&.Xr mandoc 1 \&Ns s behaviour
   .Ss \&br
   Emits a line-break.
   This macro should not be used; it is implemented for compatibility with
   historical manuals.
   .Pp
   Consider using
   .Sx \&Pp
   in the event of natural paragraph breaks.
   .Ss \&sp
   Emits vertical space.
   This macro should not be used; it is implemented for compatibility with
   historical manuals.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&sp Op Ar height
   .Pp
   The
   .Ar height
   argument must be formatted as described in
   .Sx Scaling Widths .
   If unspecified,
   .Sx \&sp
   asserts a single vertical space.
 .Sh COMPATIBILITY  .Sh COMPATIBILITY
 The mdoc language was traditionally a  This section documents compatibility between mandoc and other other
 .Qq roff  troff implementations, at this time limited to GNU troff
 macro package; most existing manuals were written with mdoc syntax  .Pq Qq groff .
 dictated by system-dependent roff installations.  This section documents  The term
 compatibility with these systems.  .Qq historic groff
   refers to groff versions before 1.17,
   which featured a significant update of the
   .Pa doc.tmac
   file.
 .Pp  .Pp
   Heirloom troff, the other significant troff implementation accepting
   \-mdoc, is similar to historic groff.
   .Pp
   The following problematic behaviour is found in groff:
   .ds hist (Historic groff only.)
   .Pp
 .Bl -dash -compact  .Bl -dash -compact
 .\" LIST-ITEM  
 .It  .It
 .Sq \&.Fo  Display macros
   .Po
   .Sx \&Bd ,
   .Sx \&Dl ,
 and  and
 .Sq \&.St  .Sx \&D1
 historically weren't always callable.  Both are now correctly callable.  .Pc
 .\" LIST-ITEM  may not be nested.
   \*[hist]
 .It  .It
 .Sq \&.It \-nested  .Sx \&At
 is assumed for all lists: any list may be nested and  with unknown arguments produces no output at all.
 .Sq \-enum  \*[hist]
 lists will restart the sequence only for the sub-list.  Newer groff and mandoc print
 .\" LIST-ITEM  .Qq AT&T UNIX
   and the arguments.
 .It  .It
 .Sq \&.It \-column  .Sx \&Bl Fl column
 syntax where column widths may be preceeded by other arguments (instead  does not recognise trailing punctuation characters when they immediately
 of proceeded) is not supported.  precede tabulator characters, but treats them as normal text and
 .\" LIST-ITEM  outputs a space before them.
 .It  .It
 The  .Sx \&Bd Fl ragged compact
 .Sq \&.At  does not start a new line.
 macro only accepts a single parameter.  \*[hist]
 .\" LIST-ITEM  
 .It  .It
 The system-name macros (  .Sx \&Dd
 .Ns Sq \&.At ,  with non-standard arguments behaves very strangely.
 .Sq \&.Bsx ,  When there are three arguments, they are printed verbatim.
 .Sq \&.Bx ,  Any other number of arguments is replaced by the current date,
 .Sq \&.Fx ,  but without any arguments the string
 .Sq \&.Nx ,  .Dq Epoch
 .Sq \&.Ox ,  is printed.
   .It
   .Sx \&Fl
   does not print a dash for an empty argument.
   \*[hist]
   .It
   .Sx \&Fn
   does not start a new line unless invoked as the line macro in the
   .Em SYNOPSIS
   section.
   \*[hist]
   .It
   .Sx \&Fo
   with
   .Pf non- Sx \&Fa
   children causes inconsistent spacing between arguments.
   In mandoc, a single space is always inserted between arguments.
   .It
   .Sx \&Ft
   in the
   .Em SYNOPSIS
   causes inconsistent vertical spacing, depending on whether a prior
   .Sx \&Fn
   has been invoked.
   See
   .Sx \&Ft
 and  and
 .Sq \&.Ux )  .Sx \&Fn
 are callable.  for the normalised behaviour in mandoc.
 .\" LIST-ITEM  
 .It  .It
 Some manuals use  .Sx \&In
 .Sq \&.Li  ignores additional arguments and is not treated specially in the
 incorrectly by following it with a reserved character and expecting the  .Em SYNOPSIS .
 delimiter to render.  This is not supported.  \*[hist]
 .\" LIST-ITEM  
 .It  .It
 .Sq \&.Cd  .Sx \&It
 is callable.  sometimes requires a
 .El  .Fl nested
 .\" SECTION  flag.
 .Sh SEE ALSO  \*[hist]
 .Xr mandoc 1 ,  In new groff and mandoc, any list may be nested by default and
 .Xr mandoc_char 7  .Fl enum
 .\" SECTION  lists will restart the sequence only for the sub-list.
 .Sh AUTHORS  
 The  
 .Nm  
 utility was written by  
 .An Kristaps Dzonsons Aq kristaps@openbsd.org .  
 .\" SECTION  
 .Sh CAVEATS  
 There are several ambiguous parts of mdoc.  
 .Pp  
 .Bl -dash -compact  
 .\" LIST-ITEM  
 .It  .It
 .Sq \&.Fa  .Sx \&Li
 should be  followed by a delimiter is incorrectly used in some manuals
 .Sq \&.Va  instead of properly quoting that character, which sometimes works with
 as function arguments are variables.  historic groff.
 .\" LIST-ITEM  
 .It  .It
 .Sq \&.Ft  .Sx \&Lk
 should be  only accepts a single link-name argument; the remainder is misformatted.
 .Sq \&.Vt  
 as function return types are still types.  Furthermore, the  
 .Sq \&.Ft  
 should be removed and  
 .Sq \&.Fo ,  
 which ostensibly follows it, should follow the same convention as  
 .Sq \&.Va .  
 .\" LIST-ITEM  
 .It  .It
 .Sq \&.Va  .Sx \&Pa
 should formalise that only one or two arguments are acceptable: a  does not format its arguments when used in the FILES section under
 variable name and optional, preceeding type.  certain list types.
 .\" LIST-ITEM  
 .It  .It
 .Sq \&.Fd  .Sx \&Ta
 is ambiguous.  It's commonly used to indicate an include file in the  can only be called by other macros, but not at the beginning of a line.
 synopsis section.  
 .Sq \&.In  
 should be used, instead.  
 .\" LIST-ITEM  
 .It  .It
 Only the  .Sx \&%C
 .Sq \-literal  is not implemented.
 argument to  
 .Sq \&.Bd  
 makes sense.  The remaining ones should be removed.  
 .\" LIST-ITEM  
 .It  .It
 The  Historic groff only allows up to eight or nine arguments per macro input
 .Sq \&.Xo  line, depending on the exact situation.
   Providing more arguments causes garbled output.
   The number of arguments on one input line is not limited with mandoc.
   .It
   Historic groff has many un-callable macros.
   Most of these (excluding some block-level macros) are callable
   in new groff and mandoc.
   .It
   .Sq \(ba
   (vertical bar) is not fully supported as a delimiter.
   \*[hist]
   .It
   .Sq \ef
   .Pq font face
 and  and
 .Sq \&.Xc  .Sq \ef
 macros should be deprecated.  .Pq font family face
 .\" LIST-ITEM  .Sx Text Decoration
   escapes behave irregularly when specified within line-macro scopes.
 .It  .It
   Negative scaling units return to prior lines.
   Instead, mandoc truncates them to zero.
   .El
   .Pp
   The following features are unimplemented in mandoc:
   .Pp
   .Bl -dash -compact
   .It
   .Sx \&Bd
   .Fl file Ar file .
   .It
   .Sx \&Bd
   .Fl offset Ar center
   and
   .Fl offset Ar right .
   Groff does not implement centred and flush-right rendering either,
   but produces large indentations.
   .It
 The  The
 .Sq \&.Dt  .Sq \eh
 macro lacks clarity.  It should be absolutely clear which title will  .Pq horizontal position ,
 render when formatting the manual page.  .Sq \ev
 .\" LIST-ITEM  .Pq vertical position ,
   .Sq \em
   .Pq text colour ,
   .Sq \eM
   .Pq text filling colour ,
   .Sq \ez
   .Pq zero-length character ,
   .Sq \ew
   .Pq string length ,
   .Sq \ek
   .Pq horizontal position marker ,
   .Sq \eo
   .Pq text overstrike ,
   and
   .Sq \es
   .Pq text size
   escape sequences are all discarded in mandoc.
 .It  .It
 A  The
 .Sq \&.Lx  .Sq \ef
 should be provided for Linux (\(`a la  scaling unit is accepted by mandoc, but rendered as the default unit.
 .Sq \&.Ox ,  
 .Sq \&.Nx  
 etc.).  
 .\" LIST-ITEM  
 .It  .It
 There's no way to refer to references in  In quoted literals, groff allows pairwise double-quotes to produce a
 .Sq \&.Rs/.Re  standalone double-quote in formatted output.
 blocks.  This is not supported by mandoc.
 .El  .El
   .Sh SEE ALSO
   .Xr man 1 ,
   .Xr mandoc 1 ,
   .Xr eqn 7 ,
   .Xr man 7 ,
   .Xr mandoc_char 7 ,
   .Xr roff 7 ,
   .Xr tbl 7
   .Sh HISTORY
   The
   .Nm
   language first appeared as a troff macro package in
   .Bx 4.4 .
   It was later significantly updated by Werner Lemberg and Ruslan Ermilov
   in groff-1.17.
   The standalone implementation that is part of the
   .Xr mandoc 1
   utility written by Kristaps Dzonsons appeared in
   .Ox 4.6 .
   .Sh AUTHORS
   The
   .Nm
   reference was written by
   .An Kristaps Dzonsons ,
   .Mt kristaps@bsd.lv .
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