+language supports authoring of manual pages for the
+.Xr man 1
+utility by allowing semantic annotations of words, phrases,
+page sections and complete manual pages.
+Such annotations are used by formatting tools to achieve a uniform
+presentation across all manuals written in
+.Nm ,
+and to support hyperlinking if supported by the output medium.
+.Pp
+This reference document describes the structure of manual pages
+and the syntax and usage of the
+.Nm
+language.
+The reference implementation of a parsing and formatting tool is
+.Xr mandoc 1 ;
+the
+.Sx COMPATIBILITY
+section describes compatibility with other implementations.
+.Pp
+In an
+.Nm
+document, lines beginning with the control character
+.Sq \&.
+are called
+.Dq macro lines .
+The first word is the macro name.
+It consists of two or three letters.
+Most macro names begin with a capital letter.
+For a list of available macros, see
+.Sx MACRO OVERVIEW .
+The words following the macro name are arguments to the macro, optionally
+including the names of other, callable macros; see
+.Sx MACRO SYNTAX
+for details.
+.Pp
+Lines not beginning with the control character are called
+.Dq text lines .
+They provide free-form text to be printed; the formatting of the text
+depends on the respective processing context:
+.Bd -literal -offset indent
+\&.Sh Macro lines change control state.
+Text lines are interpreted within the current state.
+.Ed
+.Pp
+Many aspects of the basic syntax of the
+.Nm
+language are based on the
+.Xr roff 7
+language; see the
+.Em LANGUAGE SYNTAX
+and
+.Em MACRO SYNTAX
+sections in the
+.Xr roff 7
+manual for details, in particular regarding
+comments, escape sequences, whitespace, and quoting.
+However, using
+.Xr roff 7
+requests in
+.Nm
+documents is discouraged;
+.Xr mandoc 1
+supports some of them merely for backward compatibility.
+.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, and 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 CONTEXT
+\&.\e\(dq For section 9 functions only.
+\&.\e\(dq .Sh IMPLEMENTATION NOTES
+\&.\e\(dq Not used in OpenBSD.
+\&.\e\(dq .Sh RETURN VALUES
+\&.\e\(dq For sections 2, 3, and 9 function return values only.
+\&.\e\(dq .Sh ENVIRONMENT
+\&.\e\(dq For sections 1, 6, 7, and 8 only.
+\&.\e\(dq .Sh FILES
+\&.\e\(dq .Sh EXIT STATUS
+\&.\e\(dq For sections 1, 6, and 8 only.
+\&.\e\(dq .Sh EXAMPLES
+\&.\e\(dq .Sh DIAGNOSTICS
+\&.\e\(dq For sections 1, 4, 6, 7, 8, and 9 printf/stderr messages only.
+\&.\e\(dq .Sh ERRORS
+\&.\e\(dq For sections 2, 3, 4, and 9 errno settings 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
+.Sx \&Fn ) ,
+they are separated by a vertical space, unless in the case of
+.Sx \&Fo ,
+.Sx \&Fn ,
+and
+.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
+List the options in alphabetical order,
+uppercase before lowercase for each letter and
+with no regard to whether an option takes an argument.
+Put digits in ascending order before all letter options.
+.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 CONTEXT
+This section lists the contexts in which functions can be called in section 9.
+The contexts are autoconf, process, or interrupt.
+.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 messages.
+In section 4 and 9 manuals, these are usually messages printed by the
+kernel to the console and to the kernel log.
+In section 1, 6, 7, and 8, these are usually messages printed by
+userland programs to the standard error output.
+.Pp
+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
+.Xr errno 2
+settings in sections 2, 3, 4, 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 (ignoring case).
+.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 OVERVIEW
+This overview is sorted such that macros of similar purpose are listed
+together, to help find the best macro for any given purpose.
+Deprecated macros are not included in the overview, but can be found below
+in the alphabetical
+.Sx MACRO REFERENCE .
+.Ss Document preamble and NAME section macros
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&Dd Ta document date: Cm $\&Mdocdate$ | Ar month day , year
+.It Sx \&Dt Ta document title: Ar TITLE section Op Ar arch
+.It Sx \&Os Ta operating system version: Op Ar system Op Ar version
+.It Sx \&Nm Ta document name (one argument)
+.It Sx \&Nd Ta document description (one line)
+.El
+.Ss Sections and cross references
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&Sh Ta section header (one line)
+.It Sx \&Ss Ta subsection header (one line)
+.It Sx \&Sx Ta internal cross reference to a section or subsection
+.It Sx \&Xr Ta cross reference to another manual page: Ar name section
+.It Sx \&Pp , \&Lp Ta start a text paragraph (no arguments)
+.El
+.Ss Displays and lists
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&Bd , \&Ed Ta display block:
+.Fl Ar type
+.Op Fl offset Ar width
+.Op Fl compact
+.It Sx \&D1 Ta indented display (one line)
+.It Sx \&Dl Ta indented literal display (one line)
+.It Sx \&Ql Ta in-line literal display: Ql text
+.It Sx \&Bl , \&El Ta list block:
+.Fl Ar type
+.Op Fl width Ar val
+.Op Fl offset Ar val
+.Op Fl compact
+.It Sx \&It Ta list item (syntax depends on Fl Ar type )
+.It Sx \&Ta Ta table cell separator in Sx \&Bl Fl column No lists
+.It Sx \&Rs , \&%* , \&Re Ta bibliographic block (references)
+.El
+.Ss Spacing control
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&Pf Ta prefix, no following horizontal space (one argument)
+.It Sx \&Ns Ta roman font, no preceding horizontal space (no arguments)
+.It Sx \&Ap Ta apostrophe without surrounding whitespace (no arguments)
+.It Sx \&Sm Ta switch horizontal spacing mode: Op Cm on | off
+.It Sx \&Bk , \&Ek Ta keep block: Fl words
+.El
+.Ss Semantic markup for command line utilities
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&Nm Ta start a SYNOPSIS block with the name of a utility
+.It Sx \&Fl Ta command line options (flags) (>=0 arguments)
+.It Sx \&Cm Ta command modifier (>0 arguments)
+.It Sx \&Ar Ta command arguments (>=0 arguments)
+.It Sx \&Op , \&Oo , \&Oc Ta optional syntax elements (enclosure)
+.It Sx \&Ic Ta internal or interactive command (>0 arguments)
+.It Sx \&Ev Ta environmental variable (>0 arguments)
+.It Sx \&Pa Ta file system path (>=0 arguments)
+.El
+.Ss Semantic markup for function libraries
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&Lb Ta function library (one argument)
+.It Sx \&In Ta include file (one argument)
+.It Sx \&Fd Ta other preprocessor directive (>0 arguments)
+.It Sx \&Ft Ta function type (>0 arguments)
+.It Sx \&Fo , \&Fc Ta function block: Ar funcname
+.It Sx \&Fn Ta function name:
+.Op Ar functype
+.Ar funcname
+.Oo
+.Op Ar argtype
+.Ar argname
+.Oc
+.It Sx \&Fa Ta function argument (>0 arguments)
+.It Sx \&Vt Ta variable type (>0 arguments)
+.It Sx \&Va Ta variable name (>0 arguments)
+.It Sx \&Dv Ta defined variable or preprocessor constant (>0 arguments)
+.It Sx \&Er Ta error constant (>0 arguments)
+.It Sx \&Ev Ta environmental variable (>0 arguments)
+.El
+.Ss Various semantic markup
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&An Ta author name (>0 arguments)
+.It Sx \&Lk Ta hyperlink: Ar uri Op Ar name
+.It Sx \&Mt Ta Do mailto Dc hyperlink: Ar address
+.It Sx \&Cd Ta kernel configuration declaration (>0 arguments)
+.It Sx \&Ad Ta memory address (>0 arguments)
+.It Sx \&Ms Ta mathematical symbol (>0 arguments)
+.El
+.Ss Physical markup
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&Em Ta italic font or underline (emphasis) (>0 arguments)
+.It Sx \&Sy Ta boldface font (symbolic) (>0 arguments)
+.It Sx \&Li Ta typewriter font (literal) (>0 arguments)
+.It Sx \&No Ta return to roman font (normal) (no arguments)
+.It Sx \&Bf , \&Ef Ta font block:
+.Op Fl Ar type | Cm \&Em | \&Li | \&Sy
+.El
+.Ss Physical enclosures
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&Dq , \&Do , \&Dc Ta enclose in typographic double quotes: Dq text
+.It Sx \&Qq , \&Qo , \&Qc Ta enclose in typewriter double quotes: Qq text
+.It Sx \&Sq , \&So , \&Sc Ta enclose in single quotes: Sq text
+.It Sx \&Pq , \&Po , \&Pc Ta enclose in parentheses: Pq text
+.It Sx \&Bq , \&Bo , \&Bc Ta enclose in square brackets: Bq text
+.It Sx \&Brq , \&Bro , \&Brc Ta enclose in curly braces: Brq text
+.It Sx \&Aq , \&Ao , \&Ac Ta enclose in angle brackets: Aq text
+.It Sx \&Eo , \&Ec Ta generic enclosure
+.El
+.Ss Text production
+.Bl -column "Brq, Bro, Brc" description
+.It Sx \&Ex Fl std Ta standard command exit values: Op Ar utility ...
+.It Sx \&Rv Fl std Ta standard function return values: Op Ar function ...
+.It Sx \&St Ta reference to a standards document (one argument)
+.It Sx \&At Ta At
+.It Sx \&Bx Ta Bx
+.It Sx \&Bsx Ta Bsx
+.It Sx \&Nx Ta Nx
+.It Sx \&Fx Ta Fx
+.It Sx \&Ox Ta Ox
+.It Sx \&Dx Ta Dx
+.El
+.Sh MACRO 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
+.Pp
+The default is
+.Fl nosplit .
+The effect of selecting either of the
+.Fl split
+modes ends at the beginning of the
+.Em AUTHORS
+section.
+In the
+.Em AUTHORS
+section, the default is
+.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 \&Mt kristaps@bsd.lv
+.Ss \&Ao
+Begin a block enclosed by angle brackets.
+Does not have any head arguments.
+This macro is almost never useful.
+See
+.Sx \&Aq
+for more details.
+.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.
+The only important use case is for email addresses.
+See
+.Sx \&Mt
+for an example.
+.Pp
+Occasionally, it is used for names of characters and keys, for example:
+.Bd -literal -offset indent
+Press the
+\&.Aq escape
+key to ...
+.Ed
+.Pp
+For URIs, use
+.Sx \&Lk
+instead, and
+.Sx \&In
+for
+.Dq #include
+directives.
+Never wrap
+.Sx \&Ar
+in
+.Sx \&Aq .
+.Pp
+Since
+.Sx \&Aq
+usually renders with non-ASCII characters in non-ASCII output modes,
+do not use it where the ASCII characters
+.Sq <
+and
+.Sq >
+are required as syntax elements.
+Instead, use these characters directly in such cases, combining them
+with the macros
+.Sx \&Pf ,
+.Sx \&Ns ,
+or
+.Sx \&Eo
+as needed.
+.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
+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 | V.[1-4]
+A version of
+.At V .
+.El
+.Pp
+Note that these arguments do not begin with a hyphen.
+.Pp
+Examples:
+.Dl \&.At
+.Dl \&.At III
+.Dl \&.At V.1
+.Pp
+See also
+.Sx \&Bsx ,
+.Sx \&Bx ,
+.Sx \&Dx ,
+.Sx \&Fx ,
+.Sx \&Nx ,
+and
+.Sx \&Ox .
+.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 center-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
+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 center axis.
+.It
+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
+A scaling width as described in
+.Xr roff 7 .
+.It
+An arbitrary string, which indents by the length of this string.
+.El
+.Pp
+When the argument is missing,
+.Fl offset
+is ignored.
+.It Fl compact
+Do not assert vertical space before the display.
+.El
+.Pp
+Examples:
+.Bd -literal -offset indent
+\&.Bd \-literal \-offset indent \-compact
+ Hello world.
+\&.Ed
+.Ed
+.Pp
+See also
+.Sx \&D1
+and
+.Sx \&Dl .
+.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
+.Pp
+The
+.Fl emphasis
+and
+.Cm \&Em
+argument are equivalent, as are
+.Fl symbolic
+and
+.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
+.Pp
+Be careful in using over-long lines within a keep block!
+Doing so will clobber the right margin.
+.Ss \&Bl
+Begin a list.
+Lists consist of items specified using the
+.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
+.Pp
+The list
+.Ar type
+is mandatory and must be specified first.
+The
+.Fl width
+and
+.Fl offset
+arguments accept macro names as described for
+.Sx \&Bd
+.Fl offset ,
+scaling widths as described in
+.Xr roff 7 ,
+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, the string length of each argument
+specifies the width of one column.
+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
+.Pp
+See also
+.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
+.Bsx
+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 ,
+and
+.Sx \&Ox .
+.Ss \&Bt
+Supported only for compatibility, do not use this in new manuals.
+Prints
+.Dq is currently in beta test.
+.Ss \&Bx
+Format the
git.ckatri.com / mandoc.git / blobdiff