Provided by: mandoc_1.14.6-3_amd64 bug

NAME

       mdoc — semantic markup language for formatting manual pages

DESCRIPTION

       The  mdoc  language  supports  authoring  of  manual  pages  for  the 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 mdoc, and to support
       hyperlinking if supported by the output medium.

       This reference document describes the structure of manual pages and the syntax  and  usage  of  the  mdoc
       language.    The   reference   implementation  of  a  parsing  and  formatting  tool  is  mandoc(1);  the
       “COMPATIBILITY” section describes compatibility with other implementations.

       In an mdoc document, lines beginning with the control character ‘.’ are called “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 “MACRO OVERVIEW”.  The words following the  macro  name  are
       arguments  to the macro, optionally including the names of other, callable macros; see “MACRO SYNTAX” for
       details.

       Lines not beginning with the control character are called “text lines”.  They provide free-form  text  to
       be printed; the formatting of the text depends on the respective processing context:

             .Sh Macro lines change control state.
             Text lines are interpreted within the current state.

       Many aspects of the basic syntax of the mdoc language are based on the roff(7) language; see the LANGUAGE
       SYNTAX  and  MACRO  SYNTAX  sections in the roff(7) manual for details, in particular regarding comments,
       escape sequences, whitespace, and  quoting.   However,  using  roff(7)  requests  in  mdoc  documents  is
       discouraged; mandoc(1) supports some of them merely for backward compatibility.

MANUAL STRUCTURE

       A well-formed mdoc document consists of a document prologue followed by one or more sections.

       The prologue, which consists of the Dd, Dt, and Os macros in that order, is required for every document.

       The  first  section  (sections are denoted by Sh) must be the NAME section, consisting of at least one Nm
       followed by Nd.

       Following that, convention dictates specifying at least the SYNOPSIS and DESCRIPTION  sections,  although
       this varies between manual sections.

       The following is a well-formed skeleton mdoc file for a utility "progname":

             .Dd $Mdocdate$
             .Dt PROGNAME section
             .Os
             .Sh NAME
             .Nm progname
             .Nd one line about what it does
             .\" .Sh LIBRARY
             .\" For sections 2, 3, and 9 only.
             .\" Not used in OpenBSD.
             .Sh SYNOPSIS
             .Nm progname
             .Op Fl options
             .Ar
             .Sh DESCRIPTION
             The
             .Nm
             utility processes files ...
             .\" .Sh CONTEXT
             .\" For section 9 functions only.
             .\" .Sh IMPLEMENTATION NOTES
             .\" Not used in OpenBSD.
             .\" .Sh RETURN VALUES
             .\" For sections 2, 3, and 9 function return values only.
             .\" .Sh ENVIRONMENT
             .\" For sections 1, 6, 7, and 8 only.
             .\" .Sh FILES
             .\" .Sh EXIT STATUS
             .\" For sections 1, 6, and 8 only.
             .\" .Sh EXAMPLES
             .\" .Sh DIAGNOSTICS
             .\" For sections 1, 4, 6, 7, 8, and 9 printf/stderr messages only.
             .\" .Sh ERRORS
             .\" For sections 2, 3, 4, and 9 errno settings only.
             .\" .Sh SEE ALSO
             .\" .Xr foobar 1
             .\" .Sh STANDARDS
             .\" .Sh HISTORY
             .\" .Sh AUTHORS
             .\" .Sh CAVEATS
             .\" .Sh BUGS
             .\" .Sh SECURITY CONSIDERATIONS
             .\" Not used in OpenBSD.

       The  sections  in  an  mdoc document are conventionally ordered as they appear above.  Sections should be
       composed as follows:

             NAME
             The name(s) and a one line description of the documented material.  The syntax for this as follows:

                   .Nm name0 ,
                   .Nm name1 ,
                   .Nm name2
                   .Nd a one line description

             Multiple ‘Nm’ names should be separated by commas.

             The Nm macro(s) must precede the Nd macro.

             See Nm and Nd.

             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:

                   .Lb libarm

             See Lb.

             SYNOPSIS
             Documents the utility invocation syntax, function call syntax, or device configuration.

             For the first, utilities (sections 1, 6, and 8), this is generally structured as follows:

                   .Nm bar
                   .Op Fl v
                   .Op Fl o Ar file
                   .Op Ar
                   .Nm foo
                   .Op Fl v
                   .Op Fl o Ar file
                   .Op Ar

             Commands should be ordered alphabetically.

             For the second, function calls (sections 2, 3, 9):

                   .In header.h
                   .Vt extern const char *global;
                   .Ft "char *"
                   .Fn foo "const char *src"
                   .Ft "char *"
                   .Fn bar "const char *src"

             Ordering of In, Vt, Fn, and Fo macros should follow C header-file conventions.

             And for the third, configurations (section 4):

                   .Cd "it* at isa? port 0x2e"
                   .Cd "it* at isa? port 0x4e"

             Manuals not in these sections generally don't need a SYNOPSIS.

             Some macros are displayed differently in the SYNOPSIS section, particularly Nm, Cd, Fd, Fn, Fo, In,
             Vt,  and  Ft.  All of these macros are output on their own line.  If two such dissimilar macros are
             pairwise invoked (except for Ft before Fo or Fn), they are separated by a vertical space, unless in
             the case of Fo, Fn, and Ft, which are always separated by vertical space.

             When text and macros following an 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 Nm
             macro, up to the next Nm, Sh, or Ss macro or the end of an enclosing block, whichever comes first.

             DESCRIPTION
             This begins with an expansion of the brief, one line description in NAME:

                   The
                   .Nm
                   utility does this, that, and the other.

             It usually follows with a breakdown of the options (if documenting a command), such as:

                   The options are as follows:
                   .Bl -tag -width Ds
                   .It Fl v
                   Print verbose information.
                   .El

             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.

             Manuals not documenting a command won't include the above fragment.

             Since the DESCRIPTION section usually contains most of the text of a manual, longer  manuals  often
             use  the  Ss  macro  to  form subsections.  In very long manuals, the DESCRIPTION may be split into
             multiple sections, each started by an Sh macro followed by a non-standard section  name,  and  each
             having several subsections, like in the present mdoc manual.

             CONTEXT
             This  section  lists  the contexts in which functions can be called in section 9.  The contexts are
             autoconf, process, or interrupt.

             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.

             RETURN VALUES
             This section documents the return values of functions in sections 2, 3, and 9.

             See Rv.

             ENVIRONMENT
             Lists the environment variables used by the utility, and explains the syntax and semantics of their
             values.  The environ(7) manual provides examples of typical content and formatting.

             See Ev.

             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.).

             See Pa.

             EXIT STATUS
             This section documents the command exit status for section 1, 6, and  8  utilities.   Historically,
             this information was described in DIAGNOSTICS, a practise that is now discouraged.

             See Ex.

             EXAMPLES
             Example  usages.   This often contains snippets of well-formed, well-tested invocations.  Make sure
             that examples work properly!

             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.

             Historically,  this  section  was used in place of EXIT STATUS for manuals in sections 1, 6, and 8;
             however, this practise is discouraged.

             See Bl -diag.

             ERRORS
             Documents errno(2) settings in sections 2, 3, 4, and 9.

             See Er.

             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).

             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.

             See Rs and Xr.

             STANDARDS
             References any standards implemented or used.  If  not  adhering  to  any  standards,  the  HISTORY
             section should be used instead.

             See St.

             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.

             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.

             See An.

             CAVEATS
             Common misuses and misunderstandings should be explained in this section.

             BUGS
             Known bugs, limitations, and work-arounds should be described in this section.

             SECURITY CONSIDERATIONS
             Documents any security precautions that operators should consider.

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 “MACRO REFERENCE”.

   Document preamble and NAME section macros
       Dd               document date: $Mdocdate$ | month day, year
       Dt               document title: TITLE section [arch]
       Os               operating system version: [system [version]]
       Nm               document name (one argument)
       Nd               document description (one line)

   Sections and cross references
       Sh               section header (one line)
       Ss               subsection header (one line)
       Sx               internal cross reference to a section or subsection
       Xr               cross reference to another manual page: name section
       Tg               tag the definition of a term (<= 1 arguments)
       Pp               start a text paragraph (no arguments)

   Displays and lists
       Bd, Ed           display block: -type [-offset width] [-compact]
       D1               indented display (one line)
       Dl               indented literal display (one line)
       Ql               in-line literal display: ‘text’
       Bl, El           list block: -type [-width val] [-offset val] [-compact]
       It               list item (syntax depends on -type)
       Ta               table cell separator in Bl -column lists
       Rs, %*, Re       bibliographic block (references)

   Spacing control
       Pf               prefix, no following horizontal space (one argument)
       Ns               roman font, no preceding horizontal space (no arguments)
       Ap               apostrophe without surrounding whitespace (no arguments)
       Sm               switch horizontal spacing mode: [on | off]
       Bk, Ek           keep block: -words

   Semantic markup for command line utilities
       Nm               start a SYNOPSIS block with the name of a utility
       Fl               command line options (flags) (>=0 arguments)
       Cm               command modifier (>0 arguments)
       Ar               command arguments (>=0 arguments)
       Op, Oo, Oc       optional syntax elements (enclosure)
       Ic               internal or interactive command (>0 arguments)
       Ev               environmental variable (>0 arguments)
       Pa               file system path (>=0 arguments)

   Semantic markup for function libraries
       Lb               function library (one argument)
       In               include file (one argument)
       Fd               other preprocessor directive (>0 arguments)
       Ft               function type (>0 arguments)
       Fo, Fc           function block: funcname
       Fn               function name: funcname [argument ...]
       Fa               function argument (>0 arguments)
       Vt               variable type (>0 arguments)
       Va               variable name (>0 arguments)
       Dv               defined variable or preprocessor constant (>0 arguments)
       Er               error constant (>0 arguments)
       Ev               environmental variable (>0 arguments)

   Various semantic markup
       An               author name (>0 arguments)
       Lk               hyperlink: uri [display_name]
       Mt               “mailto” hyperlink: localpart@domain
       Cd               kernel configuration declaration (>0 arguments)
       Ad               memory address (>0 arguments)
       Ms               mathematical symbol (>0 arguments)

   Physical markup
       Em               italic font or underline (emphasis) (>0 arguments)
       Sy               boldface font (symbolic) (>0 arguments)
       No               return to roman font (normal) (>0 arguments)
       Bf, Ef           font block: -type | Em | Li | Sy

   Physical enclosures
       Dq, Do, Dc       enclose in typographic double quotes: “text”
       Qq, Qo, Qc       enclose in typewriter double quotes: "text"
       Sq, So, Sc       enclose in single quotes: ‘text’
       Pq, Po, Pc       enclose in parentheses: (text)
       Bq, Bo, Bc       enclose in square brackets: [text]
       Brq, Bro, Brc    enclose in curly braces: {text}
       Aq, Ao, Ac       enclose in angle brackets: ⟨text⟩
       Eo, Ec           generic enclosure

   Text production
       Ex -std          standard command exit values: [utility ...]
       Rv -std          standard function return values: [function ...]
       St               reference to a standards document (one argument)
       At               AT&T UNIX
       Bx               BSD
       Bsx              BSD/OS
       Nx               NetBSD
       Fx               FreeBSD
       Ox               OpenBSD
       Dx               DragonFly

MACRO REFERENCE

       This  section  is  a  canonical  reference  of  all  macros, arranged alphabetically.  For the scoping of
       individual macros, see “MACRO SYNTAX”.

       %A first_name ... last_name
            Author name of an Rs block.  Multiple authors should each be accorded their  own  %A  line.   Author
            names should be ordered with full or abbreviated forename(s) first, then full surname.

       %B title
            Book  title  of  an  Rs  block.   This  macro  may  also be used in a non-bibliographic context when
            referring to book titles.

       %C location
            Publication city or location of an Rs block.

       %D [month day,] year
            Publication date of an Rs block.  Provide the full English name of the month and all four digits  of
            the year.

       %I name
            Publisher or issuer name of an Rs block.

       %J name
            Journal name of an Rs block.

       %N number
            Issue number (usually for journals) of an Rs block.

       %O line
            Optional information of an Rs block.

       %P number
            Book  or  journal  page  number of an Rs block.  Conventionally, the argument starts with ‘p.’ for a
            single page or ‘pp.’ for a range of pages, for example:

                  .%P pp. 42\(en47

       %Q name
            Institutional author (school, government, etc.) of an  Rs  block.   Multiple  institutional  authors
            should each be accorded their own %Q line.

       %R name
            Technical report name of an Rs block.

       %T title
            Article  title  of  an  Rs block.  This macro may also be used in a non-bibliographical context when
            referring to article titles.

       %U protocol://path
            URI of reference document.

       %V number
            Volume number of an Rs block.

       Ac   Close an Ao block.  Does not have any tail arguments.

       Ad address
            Memory address.  Do not use this for postal addresses.

            Examples:
                  .Ad [0,$]
                  .Ad 0x00000000

       An -split | -nosplit | first_name ... last_name
            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:

                  -split     Start a new output line before each subsequent invocation of An.
                  -nosplit   The opposite of -split.

            The  default  is -nosplit.  The effect of selecting either of the -split modes ends at the beginning
            of the AUTHORS section.  In the AUTHORS section, the  default  is  -nosplit  for  the  first  author
            listing and -split for all other author listings.

            Examples:
                  .An -nosplit
                  .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv

       Ao block
            Begin  a  block enclosed by angle brackets.  Does not have any head arguments.  This macro is almost
            never useful.  See Aq for more details.

       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.

            Examples:
                  .Fn execve Ap d

       Aq line
            Enclose  the  rest  of  the  input line in angle brackets.  The only important use case is for email
            addresses.  See Mt for an example.

            Occasionally, it is used for names of characters and keys, for example:

                  Press the
                  .Aq escape
                  key to ...

            For URIs, use Lk instead, and In for “#include” directives.  Never wrap Ar in Aq.

            Since Aq usually renders with non-ASCII characters in non-ASCII output modes, do not  use  it  where
            the  ASCII  characters  ‘<’  and ‘>’ are required as syntax elements.  Instead, use these characters
            directly in such cases, combining them with the macros Pf, Ns, or Eo as needed.

            See also Ao.

       Ar [placeholder ...]
            Command arguments.  If an argument is not provided, the string “file ...” is used as a default.

            Examples:
                  .Fl o Ar file
                  .Ar
                  .Ar arg1 , arg2 .

            The arguments to the Ar macro are names and placeholders for command arguments; for fixed strings to
            be passed verbatim as arguments, use Fl or Cm.

       At [version]
            Formats an AT&T UNIX version.  Accepts one optional argument:

                  v[1-7] | 32v   A version of AT&T UNIX.
                  III            AT&T System III UNIX.
                  V | V.[1-4]    A version of AT&T System V UNIX.

            Note that these arguments do not begin with a hyphen.

            Examples:
                  .At
                  .At III
                  .At V.1

            See also Bsx, Bx, Dx, Fx, Nx, and Ox.

       Bc   Close a Bo block.  Does not have any tail arguments.

       Bd -type [-offset width] [-compact]
            Begin a display block.  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.

            The type must be one of the following:

                  -centered      Produce one output line from each input line,  and  center-justify  each  line.
                                 Using this display type is not recommended; many mdoc implementations render it
                                 poorly.

                  -filled        Change  the  positions  of  line breaks to fill each line, and left- and right-
                                 justify the resulting block.

                  -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.

                  -ragged        Change the positions of line breaks to fill each  line,  and  left-justify  the
                                 resulting block.

                  -unfilled      The  same  as  -literal, but using the same font as for normal text, which is a
                                 variable width font if supported by the output device.

            The type must be provided first.  Additional arguments may follow:

                  -offset width  Indent the display by the width, which may be one of the following:

                                 One of the pre-defined strings indent, the width of a standard indentation (six
                                 constant width characters);  indent-two,  twice  indent;  left,  which  has  no
                                 effect;  right,  which  justifies  to the right margin; or center, which aligns
                                 around an imagined center axis.

                                 A macro invocation, which selects  a  predefined  width  associated  with  that
                                 macro.  The most popular is the imaginary macro Ds, which resolves to 6n.

                                 A scaling width as described in roff(7).

                                 An arbitrary string, which indents by the length of this string.

                                 When the argument is missing, -offset is ignored.

                  -compact       Do not assert vertical space before the display.

            Examples:

                  .Bd -literal -offset indent -compact
                     Hello       world.
                  .Ed

            See also D1 and Dl.

       Bf -emphasis | -literal | -symbolic | Em | Li | Sy
            Change  the  font mode for a scoped block of text.  The -emphasis and Em argument are equivalent, as
            are -symbolic and Sy, and -literal and Li.  Without an argument, this macro does nothing.  The  font
            mode continues until broken by a new font mode in a nested scope or Ef is encountered.

            See also Li, Ef, Em, and Sy.

       Bk -words
            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 -words argument is required; additional arguments are ignored.

            The following example will not break within each Op macro line:

                  .Bk -words
                  .Op Fl f Ar flags
                  .Op Fl o Ar output
                  .Ek

            Be careful in using over-long lines within a keep block!  Doing so will clobber the right margin.

       Bl -type [-width val] [-offset val] [-compact] [col ...]
            Begin a list.  Lists consist of items specified using the It macro, containing a head or a  body  or
            both.

            The  list  type  is  mandatory and must be specified first.  The -width and -offset arguments accept
            macro names as described for Bd -offset, scaling widths as described in roff(7), or use  the  length
            of  the  given  string.  The -offset is a global indentation for the whole list, affecting both item
            heads and bodies.  For those list types supporting it, the -width argument  requests  an  additional
            indentation  of item bodies, to be added to the -offset.  Unless the -compact argument is specified,
            list entries are separated by vertical space.

            A list must specify one of the following list types:

                  -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 -width argument.

                  -column       A  columnated  list.   The  -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 -column list is not an It macro line,  It  contexts  spanning  one
                                input  line  each  are  implied  until an It macro line is encountered, at which
                                point items start being interpreted as described in the It documentation.

                  -dash         Like -bullet, except that dashes are used in place of bullets.

                  -diag         Like -inset, except that item heads are not parsed for macro invocations.   Most
                                often used in the DIAGNOSTICS section with error constants in the item heads.

                  -enum         A  numbered  list.   No  item  heads  can be specified.  Formatted like -bullet,
                                except that cardinal numbers are used in place of bullets, starting at 1.

                  -hang         Like -tag, except that the first lines of item  bodies  are  not  indented,  but
                                follow the item heads like in -inset lists.

                  -hyphen       Synonym for -dash.

                  -inset        Item  bodies  follow  items  heads  on  the  same  line, using normal inter-word
                                spacing.  Bodies are not indented, and the -width argument is ignored.

                  -item         No item heads can be specified, and none are printed.  Bodies are not  indented,
                                and the -width argument is ignored.

                  -ohang        Item  bodies  start  on the line following item heads and are not indented.  The
                                -width argument is ignored.

                  -tag          Item bodies are indented according to the -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.

            Lists may be nested within lists and displays.  Nesting of  -column  and  -enum  lists  may  not  be
            portable.

            See also El and It.

       Bo block
            Begin a block enclosed by square brackets.  Does not have any head arguments.

            Examples:
                  .Bo 1 ,
                  .Dv BUFSIZ Bc

            See also Bq.

       Bq line
            Encloses its arguments in square brackets.

            Examples:
                  .Bq 1, Dv BUFSIZ

            Remarks:  this  macro  is  sometimes  abused to emulate optional arguments for commands; the correct
            macros to use for this purpose are Op, Oo, and Oc.

            See also Bo.

       Brc  Close a Bro block.  Does not have any tail arguments.

       Bro block
            Begin a block enclosed by curly braces.  Does not have any head arguments.

            Examples:
                  .Bro 1 , ... ,
                  .Va n Brc

            See also Brq.

       Brq line
            Encloses its arguments in curly braces.

            Examples:
                  .Brq 1, ..., Va n

            See also Bro.

       Bsx [version]
            Format the BSD/OS version provided as an argument, or a default value if no argument is provided.

            Examples:
                  .Bsx 1.0
                  .Bsx

            See also At, Bx, Dx, Fx, Nx, and Ox.

       Bt   Supported only for compatibility, do not use this in new manuals.   Prints  “is  currently  in  beta
            test.”

       Bx [version [variant]]
            Format the BSD version provided as an argument, or a default value if no argument is provided.

            Examples:
                  .Bx 4.3 Tahoe
                  .Bx 4.4
                  .Bx

            See also At, Bsx, Dx, Fx, Nx, and Ox.

       Cd line
            Kernel  configuration  declaration.   This  denotes strings accepted by config(8).  It is most often
            used in section 4 manual pages.

            Examples:
                  .Cd device le0 at scode?

            Remarks: this macro is commonly abused by using quoted  literals  to  retain  whitespace  and  align
            consecutive Cd declarations.  This practise is discouraged.

       Cm keyword ...
            Command modifiers.  Typically used for fixed strings passed as arguments to interactive commands, to
            commands in interpreted scripts, or to configuration file directives, unless Fl is more appropriate.

            Examples:
                  .Nm mt Fl f Ar device Cm rewind
                  .Nm ps Fl o Cm pid , Ns Cm command
                  .Nm dd Cm if= Ns Ar file1 Cm of= Ns Ar file2
                  .Ic set Fl o Cm vi
                  .Ic lookup Cm file bind
                  .Ic permit Ar identity Op Cm as Ar target

       D1 line
            One-line indented display.  This is formatted by the default rules and is useful for simple indented
            statements.  It is followed by a newline.

            Examples:
                  .D1 Fl abcdefgh

            See also Bd and Dl.

       Db   This  macro  is obsolete.  No replacement is needed.  It is ignored by mandoc(1) and groff including
            its arguments.  It was formerly used to toggle a debugging mode.

       Dc   Close a Do block.  Does not have any tail arguments.

       Dd $Mdocdate$ | month day, year
            Document date for display in the page footer, by convention the date of the last  change.   This  is
            the mandatory first macro of any mdoc manual.

            The  month  is  the  full English month name, the day is an integer number, and the year is the full
            four-digit year.

            Other arguments are not portable; the mandoc(1) utility handles them as follows:
               -   To have the date automatically filled in by the OpenBSD version of cvs(1), the special string
                   “$Mdocdate$” can be given as an argument.
               -   The traditional, purely numeric man(7) format yearmonthday is accepted, too.
               -   If a date string cannot be parsed, it is used verbatim.
               -   If no date string is given, the current date is used.

            Examples:
                  .Dd $Mdocdate$
                  .Dd $Mdocdate: July 2 2018$
                  .Dd July 2, 2018

            See also Dt and Os.

       Dl line
            One-line indented display.  This is formatted as  literal  text  and  is  useful  for  commands  and
            invocations.  It is followed by a newline.

            Examples:
                  .Dl % mandoc mdoc.7 \(ba less

            See also Ql, Bd -literal, and D1.

       Do block
            Begin a block enclosed by double quotes.  Does not have any head arguments.

            Examples:
                  .Do
                  April is the cruellest month
                  .Dc
                  \(em T.S. Eliot

            See also Dq.

       Dq line
            Encloses its arguments in “typographic” double-quotes.

            Examples:
                  .Dq April is the cruellest month
                  \(em T.S. Eliot

            See also Qq, Sq, and Do.

       Dt TITLE section [arch]
            Document title for display in the page header.  This is the mandatory second macro of any mdoc file.

            Its arguments are as follows:

              TITLE    The  document's  title  (name),  defaulting  to  “UNTITLED” if unspecified.  To achieve a
                       uniform appearance of page header lines, it should by convention be all caps.

              section  The manual section.  This may be one  of  1  (General  Commands),  2  (System  Calls),  3
                       (Library  Functions), 3p (Perl Library), 4 (Device Drivers), 5 (File Formats), 6 (Games),
                       7 (Miscellaneous Information), 8 (System Manager's  Manual),  or  9  (Kernel  Developer's
                       Manual).   It should correspond to the manual's filename suffix and defaults to the empty
                       string if unspecified.

              arch     This specifies the machine architecture a manual page applies  to,  where  relevant,  for
                       example  alpha,  amd64,  i386,  or  sparc64.   The  list of valid architectures varies by
                       operating system.

            Examples:
                  .Dt FOO 1
                  .Dt FOO 9 i386

            See also Dd and Os.

       Dv identifier ...
            Defined variables such as preprocessor constants, constant symbols, enumeration values, and so on.

            Examples:
                  .Dv NULL
                  .Dv BUFSIZ
                  .Dv STDOUT_FILENO

            See also Er and Ev for special-purpose constants, Va  for  variable  symbols,  and  Fd  for  listing
            preprocessor variable definitions in the SYNOPSIS.

       Dx [version]
            Format the DragonFly version provided as an argument, or a default value if no argument is provided.

            Examples:
                  .Dx 2.4.1
                  .Dx

            See also At, Bsx, Bx, Fx, Nx, and Ox.

       Ec [closing_delimiter]
            Close a scope started by Eo.

            The  closing_delimiter  argument  is  used  as the enclosure tail, for example, specifying \(rq will
            emulate Dc.

       Ed   End a display context started by Bd.

       Ef   End a font mode context started by Bf.

       Ek   End a keep context started by Bk.

       El   End a list context started by Bl.  See also It.

       Em word ...
            Request an italic font.  If the output device does not provide that, underline.

            This is most often used for stress emphasis (not to be confused with importance, see  Sy).   In  the
            rare cases where none of the semantic markup macros fit, it can also be used for technical terms and
            placeholders, except that for syntax elements, Sy and Ar are preferred, respectively.

            Examples:
                  Selected lines are those
                  .Em not
                  matching any of the specified patterns.
                  Some of the functions use a
                  .Em hold space
                  to save the pattern space for subsequent retrieval.

            See also No, Ql, and Sy.

       En word ...
            This macro is obsolete.  Use Eo or any of the other enclosure macros.

            It encloses its argument in the delimiters specified by the last Es macro.

       Eo [opening_delimiter]
            An  arbitrary enclosure.  The opening_delimiter argument is used as the enclosure head, for example,
            specifying \(lq will emulate Do.

       Er identifier ...
            Error constants for definitions of the errno libc global variable.   This  is  most  often  used  in
            section 2 and 3 manual pages.

            Examples:
                  .Er EPERM
                  .Er ENOENT

            See also Dv for general constants.

       Es opening_delimiter closing_delimiter
            This macro is obsolete.  Use Eo or any of the other enclosure macros.

            It takes two arguments, defining the delimiters to be used by subsequent En macros.

       Ev identifier ...
            Environmental variables such as those specified in environ(7).

            Examples:
                  .Ev DISPLAY
                  .Ev PATH

            See also Dv for general constants.

       Ex -std [utility ...]
            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.

            If  utility is not specified, the document's name set by Nm is used.  Multiple utility arguments are
            treated as separate utilities.

            See also Rv.

       Fa argument ...
            Function argument or parameter.  Each argument may be  a  name  and  a  type  (recommended  for  the
            SYNOPSIS  section),  a  name  alone  (for  function  invocations),  or  a  type  alone (for function
            prototypes).  If both a type and a name are given or if the type consists  of  multiple  words,  all
            words belonging to the same function argument have to be given in a single argument to the Fa macro.

            This macro is also used to specify the field name of a structure.

            Most  often,  the  Fa  macro  is  used  in the SYNOPSIS within Fo blocks 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 Fa, the last argument will also have a trailing
            comma.

            Examples:
                  .Fa "const char *p"
                  .Fa "int a" "int b" "int c"
                  .Fa "char *" size_t

            See also Fo.

       Fc   End a function context started by Fo.

       Fd #directive [argument ...]
            Preprocessor directive, in particular for listing it in the SYNOPSIS.   Historically,  it  was  also
            used to document include files.  The latter usage has been deprecated in favour of In.

            Examples:
                  .Fd #define sa_handler __sigaction_u.__sa_handler
                  .Fd #define SIO_MAXNFDS
                  .Fd #ifdef FS_DEBUG
                  .Ft void
                  .Fn dbg_open "const char *"
                  .Fd #endif

            See also “MANUAL STRUCTURE”, In, and Dv.

       Fl [word ...]
            Command-line  flag  or  option.   Used  when  listing arguments to command-line utilities.  For each
            argument, prints an ASCII hyphen-minus character ‘-’, immediately followed by the argument.   If  no
            arguments  are provided, a hyphen-minus is printed followed by a space.  If the argument is a macro,
            a hyphen-minus is prefixed to the subsequent macro output.

            Examples:
                  .Nm du Op Fl H | L | P
                  .Nm ls Op Fl 1AaCcdFfgHhikLlmnopqRrSsTtux
                  .Nm route Cm add Fl inet Ar destination gateway
                  .Nm locate.updatedb Op Fl \-fcodes Ns = Ns Ar dbfile
                  .Nm aucat Fl o Fl
                  .Nm kill Fl Ar signal_number

            For GNU-sytle long options, escaping the additional hyphen-minus is not strictly required,  but  may
            be safer with future versions of GNU troff; see mandoc_char(7) for details.

            See also Cm.

       Fn funcname [argument ...]
            A function name.

            Function  arguments  are surrounded in parenthesis and are delimited by commas.  If no arguments are
            specified, blank parenthesis are output.  In the SYNOPSIS section, this macro starts  a  new  output
            line, and a blank line is automatically inserted between function definitions.

            Examples:
                  .Fn "int funcname" "int arg0" "int arg1"
                  .Fn funcname "int arg0"
                  .Fn funcname arg0

                  .Ft functype
                  .Fn funcname

            When  referring  to  a function documented in another manual page, use Xr instead.  See also “MANUAL
            STRUCTURE”, Fo, and Ft.

       Fo funcname
            Begin a function block.  This is a multi-line version of Fn.

            Invocations usually occur in the following context:

                  .Ft functype
                  .Fo funcname
                  .Fa "argtype argname"
                  ...
                  .Fc

            A Fo scope is closed by Fc.

            See also “MANUAL STRUCTURE”, Fa, Fc, and Ft.

       Fr number
            This macro is obsolete.  No replacement markup is needed.

            It was used to show numerical function return values in an italic font.

       Ft functype
            A function type.

            In the SYNOPSIS section, a new output line is started after this macro.

            Examples:
                  .Ft int
                  .Ft functype
                  .Fn funcname

            See also “MANUAL STRUCTURE”, Fn, and Fo.

       Fx [version]
            Format the FreeBSD version provided as an argument, or a default value if no argument is provided.

            Examples:
                  .Fx 7.1
                  .Fx

            See also At, Bsx, Bx, Dx, Nx, and Ox.

       Hf filename
            This macro is not implemented in mandoc(1).  It was used to include the contents of a (header)  file
            literally.

       Ic keyword ...
            Internal or interactive command, or configuration instruction in a configuration file.  See also Cm.

            Examples:
                  .Ic :wq
                  .Ic hash
                  .Ic alias

            Note  that  using  Ql,  Dl, or Bd -literal is preferred for displaying code samples; the Ic macro is
            used when referring to an individual command name.

       In filename
            The name of an include file.  This macro is most often used in section 2, 3, and 9 manual pages.

            When invoked as the first macro on an input line in the SYNOPSIS section, the argument is  displayed
            in  angle  brackets  and preceded by "#include", and a blank line is inserted in front if there is a
            preceding function declaration.  In other sections, it only encloses its argument in angle  brackets
            and causes no line break.

            Examples:
                  .In sys/types.h

            See also “MANUAL STRUCTURE”.

       It [head]
            A list item.  The syntax of this macro depends on the list type.

            Lists of type -hang, -ohang, -inset, and -diag have the following syntax:

                  .It args

            Lists of type -bullet, -dash, -enum, -hyphen and -item have the following syntax:

                  .It

            with  subsequent  lines  interpreted within the scope of the It until either a closing El or another
            It.

            The -tag list has the following syntax:

                  .It [args]

            Subsequent lines are interpreted as with -bullet and family.  The line arguments correspond  to  the
            list's left-hand side; body arguments correspond to the list's contents.

            The -column list is the most complicated.  Its syntax is as follows:

                  .It cell [Ta cell ...]
                  .It cell [<TAB> cell ...]

            The  arguments  consist  of one or more lines of text and macros representing a complete table line.
            Cells within the line are delimited by the special Ta block macro or by literal tab characters.

            Using literal tabs is strongly discouraged because they are very hard to use correctly and mdoc code
            using them is very hard to read.  In particular, a  blank  character  is  syntactically  significant
            before  and  after  the  literal  tab  character.   If a word precedes or follows the tab without an
            intervening blank, that word is never interpreted as a macro call, but always output literally.

            The tab cell delimiter may only be used within the It line itself; on following lines, only  the  Ta
            macro can be used to delimit cells, and portability requires that Ta is called by other macros: some
            parsers do not recognize it when it appears as the first macro on a line.

            Note that quoted strings may span tab-delimited cells on an It line.  For example,

                  .It "col1 , <TAB> col2 ," ;

            will preserve the whitespace before both commas, but not the whitespace before the semicolon.

            See also Bl.

       Lb libname
            Specify a library.

            The  name  parameter  may  be  a  system  library,  such  as z or pam, 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  SYNOPSIS  section  as  described  in
            “MANUAL STRUCTURE”.

            Examples:
                  .Lb libz
                  .Lb libmandoc

       Li word ...
            Request a typewriter (literal) font.  Deprecated because on terminal output devices, this is usually
            indistinguishable from normal text.  For literal displays, use Ql (in-line), Dl (single line), or Bd
            -literal (multi-line) instead.

       Lk uri [display_name]
            Format a hyperlink.

            Examples:
                  .Lk https://bsd.lv "The BSD.lv Project"
                  .Lk https://bsd.lv

            See also Mt.

       Lp   Deprecated synonym for Pp.

       Ms name
            Display a mathematical symbol.

            Examples:
                  .Ms sigma
                  .Ms aleph

       Mt localpart@domain
            Format a “mailto:” hyperlink.

            Examples:
                  .Mt discuss@manpages.bsd.lv
                  .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv

       Nd line
            A  one  line  description  of  the  manual's  content.  This is the mandatory last macro of the NAME
            section and not appropriate for other sections.

            Examples:
                  .Nd mdoc language reference
                  .Nd format and display UNIX manuals

            The Nd macro technically accepts child macros and terminates with a subsequent  Sh  invocation.   Do
            not  assume  this  behaviour:  some whatis(1) database generators are not smart enough to parse more
            than the line arguments and will display macros verbatim.

            See also Nm.

       Nm [name]
            The name of the manual page, or — in particular in section 1, 6, and 8  pages  —  of  an  additional
            command or feature documented in the manual page.  When first invoked, the Nm macro expects a single
            argument, the name of the manual page.  Usually, the first invocation happens in the 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 Nm macro uses “Block full-implicit” semantics when invoked as the
            first macro on an input line  in  the  SYNOPSIS  section;  otherwise,  it  uses  ordinary  “In-line”
            semantics.

            Examples:

                  .Sh SYNOPSIS
                  .Nm cat
                  .Op Fl benstuv
                  .Op Ar

            In  the  SYNOPSIS of section 2, 3 and 9 manual pages, use the Fn macro rather than Nm to mark up the
            name of the manual page.

       No word ...
            Normal text.  Closes the scope of any preceding in-line macro.  When used after physical  formatting
            macros like Em or 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.

            Examples:
                  .Em italic , Sy bold , No and roman

                  .Sm off
                  .Cm :C No / Ar pattern No / Ar replacement No /
                  .Sm on

            See also Em, Ql, and Sy.

       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 No macro.

            This has no effect when invoked at the start of a macro line.

            Examples:
                  .Ar name Ns = Ns Ar value
                  .Cm :M Ns Ar pattern
                  .Fl o Ns Ar output

            See also No and Sm.

       Nx [version]
            Format the NetBSD version provided as an argument, or a default value if no argument is provided.

            Examples:
                  .Nx 5.01
                  .Nx

            See also At, Bsx, Bx, Dx, Fx, and Ox.

       Oc   Close multi-line Oo context.

       Oo block
            Multi-line version of Op.

            Examples:
                  .Oo
                  .Op Fl flag Ns Ar value
                  .Oc

       Op line
            Optional part of a command line.  Prints the argument(s) in brackets.  This is most  often  used  in
            the SYNOPSIS section of section 1 and 8 manual pages.

            Examples:
                  .Op Fl a Ar b
                  .Op Ar a | b

            See also Oo.

       Os [system [version]]
            Operating  system  version for display in the page footer.  This is the mandatory third macro of any
            mdoc file.

            The optional system parameter specifies  the  relevant  operating  system  or  environment.   It  is
            suggested  to leave it unspecified, in which case mandoc(1) uses its -Ios argument or, if that isn't
            specified either, sysname and release as returned by uname(3).

            Examples:
                  .Os
                  .Os KTH/CSC/TCS
                  .Os BSD 4.3

            See also Dd and Dt.

       Ot functype
            This macro is obsolete.  Use Ft instead; with mandoc(1), both have the same effect.

            Historical mdoc packages described it as “old function type (FORTRAN)”.

       Ox [version]
            Format the OpenBSD version provided as an argument, or a default value if no argument is provided.

            Examples:
                  .Ox 4.5
                  .Ox

            See also At, Bsx, Bx, Dx, Fx, and Nx.

       Pa name ...
            An absolute or relative file system path, or a file or  directory  name.   If  an  argument  is  not
            provided, the character ‘~’ is used as a default.

            Examples:
                  .Pa /usr/bin/mandoc
                  .Pa /usr/share/man/man7/mdoc.7

            See also Lk.

       Pc   Close parenthesised context opened by Po.

       Pf prefix macro [argument ...]
            Removes the space between its argument and the following macro.  It is equivalent to:

                  No \&prefix Ns macro [argument ...]

            The  prefix  argument  is  not parsed for macro names or delimiters, but used verbatim as if it were
            escaped.

            Examples:
                  .Pf $ Ar variable_name
                  .Pf . Ar macro_name
                  .Pf 0x Ar hex_digits

            See also Ns and Sm.

       Po block
            Multi-line version of Pq.

       Pp   Break a paragraph.  This will assert vertical space between prior and subsequent macros and/or text.

            Paragraph breaks are not needed before or after Sh or Ss macros or  before  displays  (Bd  line)  or
            lists (Bl) unless the -compact flag is given.

       Pq line
            Parenthesised enclosure.

            See also Po.

       Qc   Close quoted context opened by Qo.

       Ql line
            In-line  literal display.  This can be used for complete command invocations and for multi-word code
            examples when an indented display is not desired.

            See also Dl and Bd -literal.

       Qo block
            Multi-line version of Qq.

       Qq line
            Encloses its arguments in "typewriter" double-quotes.  Consider using Dq.

            See also Dq, Sq, and Qo.

       Re   Close an Rs block.  Does not have any tail arguments.

       Rs   Begin a bibliographic (“reference”) block.  Does not have any head arguments.  The block  macro  may
            only  contain  %A, %B, %C, %D, %I, %J, %N, %O, %P, %Q, %R, %T, %U, and %V child macros (at least one
            must be specified).

            Examples:
                  .Rs
                  .%A J. E. Hopcroft
                  .%A J. D. Ullman
                  .%B Introduction to Automata Theory, Languages, and Computation
                  .%I Addison-Wesley
                  .%C Reading, Massachusetts
                  .%D 1979
                  .Re

            If an 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.

       Rv -std [function ...]
            Insert a standard sentence regarding a function call's return value of 0 on success and -1 on error,
            with the errno libc global variable set on error.

            If  function  is  not specified, the document's name set by Nm is used.  Multiple function arguments
            are treated as separate functions.

            See also Ex.

       Sc   Close single-quoted context opened by So.

       Sh TITLE LINE
            Begin a new section.  For a list of conventional manual sections,  see  “MANUAL  STRUCTURE”.   These
            sections should be used unless it's absolutely necessary that custom sections be used.

            Section  names  should be unique so that they may be keyed by Sx.  Although this macro is parsed, it
            should not consist of child node or it may not be linked with Sx.

            See also Pp, Ss, and Sx.

       Sm [on | off]
            Switches the spacing mode for output generated from macros.

            By default, spacing is on.  When switched 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.

            When called without an argument, the  Sm  macro  toggles  the  spacing  mode.   Using  this  is  not
            recommended because it makes the code harder to read.

       So block
            Multi-line version of Sq.

       Sq line
            Encloses its arguments in ‘typewriter’ single-quotes.

            See also Dq, Qq, and So.

       Ss Title line
            Begin  a  new  subsection.   Unlike  with  Sh, there is no convention for the naming of subsections.
            Except  DESCRIPTION,  the  conventional  sections  described  in  “MANUAL  STRUCTURE”  rarely   have
            subsections.

            Sub-section  names should be unique so that they may be keyed by Sx.  Although this macro is parsed,
            it should not consist of child node or it may not be linked with Sx.

            See also Pp, Sh, and Sx.

       St -abbreviation
            Replace an abbreviation for a standard with the full form.  The following standards are  recognised.
            Where multiple lines are given without a blank line in between, they all refer to the same standard,
            and using the first form is recommended.

            C language standards

               -ansiC          ANSI X3.159-1989 (“ANSI C89”)
               -ansiC-89       ANSI X3.159-1989 (“ANSI C89”)
               -isoC           ISO/IEC 9899:1990 (“ISO C90”)
               -isoC-90        ISO/IEC 9899:1990 (“ISO C90”)
                               The original C standard.

               -isoC-amd1      ISO/IEC 9899/AMD1:1995 (“ISO C90, Amendment 1”)

               -isoC-tcor1     ISO/IEC 9899/TCOR1:1994 (“ISO C90, Technical Corrigendum 1”)

               -isoC-tcor2     ISO/IEC 9899/TCOR2:1995 (“ISO C90, Technical Corrigendum 2”)

               -isoC-99        ISO/IEC 9899:1999 (“ISO C99”)
                               The second major version of the C language standard.

               -isoC-2011      ISO/IEC 9899:2011 (“ISO C11”)
                               The third major version of the C language standard.

            POSIX.1 before the Single UNIX Specification

               -p1003.1-88     IEEE Std 1003.1-1988 (“POSIX.1”)
               -p1003.1        IEEE Std 1003.1 (“POSIX.1”)
                               The original POSIX standard, based on ANSI C.

               -p1003.1-90     ISO/IEC 9945-1:1990 (“POSIX.1”)
               -iso9945-1-90   ISO/IEC 9945-1:1990 (“POSIX.1”)
                               The first update of POSIX.1.

               -p1003.1b-93    IEEE Std 1003.1b-1993 (“POSIX.1”)
               -p1003.1b       IEEE Std 1003.1b (“POSIX.1”)
                               Real-time extensions.

               -p1003.1c-95    IEEE Std 1003.1c-1995 (“POSIX.1”)
                               POSIX thread interfaces.

               -p1003.1i-95    IEEE Std 1003.1i-1995 (“POSIX.1”)
                               Technical Corrigendum.

               -p1003.1-96     ISO/IEC 9945-1:1996 (“POSIX.1”)
               -iso9945-1-96   ISO/IEC 9945-1:1996 (“POSIX.1”)
                               Includes POSIX.1-1990, 1b, 1c, and 1i.

            X/Open Portability Guide version 4 and related standards

               -xpg3           X/Open Portability Guide Issue 3 (“XPG3”)
                               An XPG4 precursor, published in 1989.

               -p1003.2        IEEE Std 1003.2 (“POSIX.2”)
               -p1003.2-92     IEEE Std 1003.2-1992 (“POSIX.2”)
               -iso9945-2-93   ISO/IEC 9945-2:1993 (“POSIX.2”)
                               An XCU4 precursor.

               -p1003.2a-92    IEEE Std 1003.2a-1992 (“POSIX.2”)
                               Updates to POSIX.2.

               -xpg4           X/Open Portability Guide Issue 4 (“XPG4”)
                               Based on POSIX.1 and POSIX.2, published in 1992.

            Single UNIX Specification version 1 and related standards

               -susv1          Version 1 of the Single UNIX Specification (“SUSv1”)
               -xpg4.2         X/Open Portability Guide Issue 4, Version 2 (“XPG4.2”)
                               This  standard  was  published  in  1994.   It  was used as the basis for UNIX 95
                               certification.  The following three refer to parts of it.

               -xsh4.2

               -xcurses4.2     X/Open Curses Issue 4, Version 2 (“XCURSES4.2”)

               -p1003.1g-2000  IEEE Std 1003.1g-2000 (“POSIX.1”)
                               Networking APIs, including sockets.

               -svid4          System V Interface Definition, Fourth Edition (“SVID4”),
                               Published in 1995.

            Single UNIX Specification version 2 and related standards

               -susv2          Version 2 of the Single UNIX Specification (“SUSv2”) This Standard was  published
                               in  1997  and  is also called X/Open Portability Guide version 5.  It was used as
                               the basis for UNIX 98 certification.  The following refer to parts of it.

               -xbd5           X/Open Base Definitions Issue 5 (“XBD5”)

               -xsh5           X/Open System Interfaces and Headers Issue 5 (“XSH5”)

               -xcu5           X/Open Commands and Utilities Issue 5 (“XCU5”)

               -xns5           X/Open Networking Services Issue 5 (“XNS5”)
               -xns5.2         X/Open Networking Services Issue 5.2 (“XNS5.2”)

            Single UNIX Specification version 3

               -p1003.1-2001  IEEE Std 1003.1-2001 (“POSIX.1”)
               -susv3         Version 3 of the Single UNIX Specification (“SUSv3”)
                              This standard is based on C99, SUSv2, POSIX.1-1996, 1d, and 1j.  It is also called
                              X/Open Portability Guide version  6.   It  is  used  as  the  basis  for  UNIX  03
                              certification.

               -p1003.1-2004  IEEE Std 1003.1-2004 (“POSIX.1”)
                              The second and last Technical Corrigendum.

            Single UNIX Specification version 4

               -p1003.1-2008   IEEE Std 1003.1-2008 (“POSIX.1”)
               -susv4          Version 4 of the Single UNIX Specification (“SUSv4”)
                               This standard is also called X/Open Portability Guide version 7.

            Other standards

               -ieee754        IEEE Std 754-1985
                               Floating-point arithmetic.

               -iso8601        ISO 8601
                               Representation of dates and times, published in 1988.

               -iso8802-3      ISO/IEC 8802-3:1989
                               Ethernet local area networks.

               -ieee1275-94    IEEE Std 1275-1994 (“Open Firmware”)

       Sx Title line
            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.

            Examples:
                  .Sx MANUAL STRUCTURE

            See also Sh and Ss.

       Sy word ...
            Request a boldface font.

            This is most often used to indicate importance or  seriousness  (not  to  be  confused  with  stress
            emphasis,  see  Em).   When none of the semantic macros fit, it is also adequate for syntax elements
            that have to be given or that appear verbatim.

            Examples:
                  .Sy Warning :
                  If
                  .Sy s
                  appears in the owner permissions, set-user-ID mode is set.
                  This utility replaces the former
                  .Sy dumpdir
                  program.

            See also Em, No, and Ql.

       Ta   Table cell separator in Bl -column lists; can only be used below It.

       Tg [term]
            Announce that the next input line starts a definition of the term.  This macro must appear alone  on
            its  own  input  line.   The  argument defaults to the first argument of the first macro on the next
            line.  The argument may not contain whitespace characters, not even when it is quoted.   This  macro
            is a mandoc(1) extension and is typically ignored by other formatters.

            When  viewing  terminal  output  with  less(1),  the interactive :t command can be used to go to the
            definition of the term as described for the MANPAGER variable in man(1); when producing HTML output,
            a fragment identifier (id attribute) is generated, to be used for deep linking to this place of  the
            document.

            In  most  cases, adding a Tg macro would be redundant because mandoc(1) is able to automatically tag
            most definitions.  This  macro  is  intended  for  cases  where  automatic  tagging  of  a  term  is
            unsatisfactory,  for  example  if  a  definition  is not tagged automatically (false negative) or if
            places are tagged that do not define the term (false positives).  When there  is  at  least  one  Tg
            macro for a term, no other places are automatically marked as definitions of that term.

       Tn word ...
            Supported  only  for  compatibility,  do  not  use  this in new manuals.  Even though the macro name
            (“tradename”) suggests a semantic function, historic usage is inconsistent, mostly  using  it  as  a
            presentation-level macro to request a small caps font.

       Ud   Supported  only  for  compatibility,  do  not  use this in new manuals.  Prints out “currently under
            development.”

       Ux   Supported only for compatibility, do not use this in new manuals.  Prints out “Unix”.

       Va [type] identifier ...
            A variable name.

            Examples:
                  .Va foo
                  .Va const char *bar;

            For function arguments and parameters, use Fa instead.  For declarations of global variables in  the
            SYNOPSIS section, use Vt.

       Vt type [identifier]
            A variable type.

            This  is also used for indicating global variables in the SYNOPSIS section, in which case a variable
            name is also specified.  Note that it accepts “Block partial-implicit” syntax when  invoked  as  the
            first macro on an input line in the SYNOPSIS section, else it accepts ordinary “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.

            Examples:
                  .Vt unsigned char
                  .Vt extern const char * const sys_signame[] ;

            For  parameters  in  function  prototypes,  use  Fa  instead,  for function return types Ft, and for
            variable names outside the SYNOPSIS section Va, even when including a type with the name.  See  also
            “MANUAL STRUCTURE”.

       Xc   Close a scope opened by Xo.

       Xo block
            Extend the header of an 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 roff(7).

       Xr name section
            Link to another manual ("cross-reference").

            Cross reference the name and section number of another man page.

            Examples:
                  .Xr mandoc 1
                  .Xr mandoc 1 ;
                  .Xr mandoc 1 Ns s behaviour

MACRO SYNTAX

       The  syntax of a macro depends on its classification.  In this section, ‘-arg’ refers to macro arguments,
       which may be followed by zero or more ‘parm’ parameters;  ‘Yo’  opens  the  scope  of  a  macro;  and  if
       specified, ‘Yc’ closes it out.

       The  Callable  column  indicates  that the macro may also be called by passing its name as an argument to
       another macro.  For example, ‘.Op Fl O Ar file’ produces ‘[-O file]’.  To prevent a macro call and render
       the macro name literally, escape it by prepending a zero-width space, ‘\&’.  For  example,  ‘Op  \&Fl  O’
       produces  ‘[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, ‘.Fl Sh’ produces ‘-Sh’.

       The 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.

       The Scope column, if applicable, describes closure rules.

   Block full-explicit
       Multi-line scope closed by  an  explicit  closing  macro.   All  macros  contains  bodies;  only  Bf  and
       (optionally) Bl contain a head.

             .Yo [-arg [parm...]] [head...]
             [body...]
             .Yc

             Macro     Callable     Parsed     Scope
             Bd        No           No         closed by Ed
             Bf        No           No         closed by Ef
             Bk        No           No         closed by Ek
             Bl        No           No         closed by El
             Ed        No           No         opened by Bd
             Ef        No           No         opened by Bf
             Ek        No           No         opened by Bk
             El        No           No         opened by Bl

   Block full-implicit
       Multi-line  scope closed by end-of-file or implicitly by another macro.  All macros have bodies; some (It
       -bullet, -hyphen, -dash, -enum, -item) don't have heads; only one (It in Bl -column) has multiple heads.

             .Yo [-arg [parm...]] [head... [Ta head...]]
             [body...]

             Macro     Callable     Parsed     Scope
             It        No           Yes        closed by It, El
             Nd        No           No         closed by Sh
             Nm        No           Yes        closed by Nm, Sh, Ss
             Sh        No           Yes        closed by Sh
             Ss        No           Yes        closed by Sh, Ss

       Note that the Nm macro is a “Block full-implicit” macro only  when  invoked  as  the  first  macro  in  a
       SYNOPSIS section line, else it is “In-line”.

   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 (Fo, Eo) and/or tail (Ec).

             .Yo [-arg [parm...]] [head...]
             [body...]
             .Yc [tail...]

             .Yo [-arg [parm...]] [head...] [body...] Yc [tail...]

             Macro     Callable     Parsed     Scope
             Ac        Yes          Yes        opened by Ao
             Ao        Yes          Yes        closed by Ac
             Bc        Yes          Yes        closed by Bo
             Bo        Yes          Yes        opened by Bc
             Brc       Yes          Yes        opened by Bro
             Bro       Yes          Yes        closed by Brc
             Dc        Yes          Yes        opened by Do
             Do        Yes          Yes        closed by Dc
             Ec        Yes          Yes        opened by Eo
             Eo        Yes          Yes        closed by Ec
             Fc        Yes          Yes        opened by Fo
             Fo        No           No         closed by Fc
             Oc        Yes          Yes        closed by Oo
             Oo        Yes          Yes        opened by Oc
             Pc        Yes          Yes        closed by Po
             Po        Yes          Yes        opened by Pc
             Qc        Yes          Yes        opened by Oo
             Qo        Yes          Yes        closed by Oc
             Re        No           No         opened by Rs
             Rs        No           No         closed by Re
             Sc        Yes          Yes        opened by So
             So        Yes          Yes        closed by Sc
             Xc        Yes          Yes        opened by Xo
             Xo        Yes          Yes        closed by Xc

   Block partial-implicit
       Like block full-implicit, but with single-line scope closed by the end of the line.

             .Yo [-arg [val...]] [body...] [res...]

             Macro     Callable     Parsed
             Aq        Yes          Yes
             Bq        Yes          Yes
             Brq       Yes          Yes
             D1        No           Yes
             Dl        No           Yes
             Dq        Yes          Yes
             En        Yes          Yes
             Op        Yes          Yes
             Pq        Yes          Yes
             Ql        Yes          Yes
             Qq        Yes          Yes
             Sq        Yes          Yes
             Vt        Yes          Yes

       Note that the Vt macro is a “Block partial-implicit” only when invoked as the first macro in  a  SYNOPSIS
       section line, else it is “In-line”.

   Special block macro
       The Ta macro can only be used below It in Bl -column lists.  It delimits blocks representing table cells;
       these blocks have bodies, but no heads.

             Macro     Callable     Parsed     Scope
             Ta        Yes          Yes        closed by Ta, It

   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 (n), then the macro accepts an arbitrary
       number of arguments.

             .Yo [-arg [val...]] [args...] [res...]

             .Yo [-arg [val...]] [args...] Yc...

             .Yo [-arg [val...]] arg0 arg1 argN

             Macro     Callable     Parsed     Arguments
             %A        No           No         >0
             %B        No           No         >0
             %C        No           No         >0
             %D        No           No         >0
             %I        No           No         >0
             %J        No           No         >0
             %N        No           No         >0
             %O        No           No         >0
             %P        No           No         >0
             %Q        No           No         >0
             %R        No           No         >0
             %T        No           No         >0
             %U        No           No         >0
             %V        No           No         >0
             Ad        Yes          Yes        >0
             An        Yes          Yes        >0
             Ap        Yes          Yes        0
             Ar        Yes          Yes        n
             At        Yes          Yes        1
             Bsx       Yes          Yes        n
             Bt        No           No         0
             Bx        Yes          Yes        n
             Cd        Yes          Yes        >0
             Cm        Yes          Yes        >0
             Db        No           No         1
             Dd        No           No         n
             Dt        No           No         n
             Dv        Yes          Yes        >0
             Dx        Yes          Yes        n
             Em        Yes          Yes        >0
             Er        Yes          Yes        >0
             Es        Yes          Yes        2
             Ev        Yes          Yes        >0
             Ex        No           No         n
             Fa        Yes          Yes        >0
             Fd        No           No         >0
             Fl        Yes          Yes        n
             Fn        Yes          Yes        >0
             Fr        Yes          Yes        >0
             Ft        Yes          Yes        >0
             Fx        Yes          Yes        n
             Hf        No           No         n
             Ic        Yes          Yes        >0
             In        No           No         1
             Lb        No           No         1
             Li        Yes          Yes        >0
             Lk        Yes          Yes        >0
             Lp        No           No         0
             Ms        Yes          Yes        >0
             Mt        Yes          Yes        >0
             Nm        Yes          Yes        n
             No        Yes          Yes        >0
             Ns        Yes          Yes        0
             Nx        Yes          Yes        n
             Os        No           No         n
             Ot        Yes          Yes        >0
             Ox        Yes          Yes        n
             Pa        Yes          Yes        n
             Pf        Yes          Yes        1
             Pp        No           No         0
             Rv        No           No         n
             Sm        No           No         <2
             St        No           Yes        1
             Sx        Yes          Yes        >0
             Sy        Yes          Yes        >0
             Tg        No           No         <2
             Tn        Yes          Yes        >0
             Ud        No           No         0
             Ux        Yes          Yes        n
             Va        Yes          Yes        n
             Vt        Yes          Yes        >0
             Xr        Yes          Yes        2

   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 (‘\&’).  In text lines, delimiters  never  need
       escaping, but may be used as normal punctuation.

       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.  Spacing is suppressed after opening delimiters and before closing delimiters.  For example,

             .Aq ( [ word ] ) .

       renders as:

             ([⟨word⟩]).

       Opening delimiters are:

             (       left parenthesis
             [       left bracket

       Closing delimiters are:

             .       period
             ,       comma
             :       colon
             ;       semicolon
             )       right parenthesis
             ]       right bracket
             ?       question mark
             !       exclamation mark

       Note  that  even a period preceded by a backslash (‘\.’) gets this special handling; use ‘\&.’ to prevent
       that.

       Many in-line macros interrupt their scope when they encounter delimiters, and  resume  their  scope  when
       more arguments follow that are not delimiters.  For example,

             .Fl a ( b | c \*(Ba d ) e

       renders as:

             -a (-b | -c | -d) -e

       This  applies  to  both  opening and closing delimiters, and also to the middle delimiter, which does not
       suppress spacing:

             |       vertical bar

       As a special case, the predefined string \*(Ba is handled and rendered in the same way  as  a  plain  ‘|’
       character.  Using this predefined string is not recommended in new manuals.

       Appending  a  zero-width  space  (‘\&’)  to  the  end  of  an  input  line  is also useful to prevent the
       interpretation of a trailing period, exclamation or question mark as the end of a sentence,  for  example
       when an abbreviation happens to occur at the end of a text or macro input line.

   Font handling
       In  mdoc  documents,  usage of semantic markup is recommended in order to have proper fonts automatically
       selected; only when no fitting semantic markup is available, consider falling back to  “Physical  markup”
       macros.   Whenever  any  mdoc  macro  switches  the  roff(7) font mode, it will automatically restore the
       previous font when exiting its scope.  Manually switching the font using the  roff(7)  ‘\f’  font  escape
       sequences is never required.

COMPATIBILITY

       This section provides an incomplete list of compatibility issues between mandoc and GNU troff ("groff").

       The following problematic behaviour is found in groff:

       -   Pa does not format its arguments when used in the FILES section under certain list types.
       -   Ta can only be called by other macros, but not at the beginning of a line.
       -   ‘\f’  (font  face)  and  ‘\F’  (font  family  face) “Text Decoration” escapes behave irregularly when
           specified within line-macro scopes.
       -   Negative scaling units return to prior lines.  Instead, mandoc truncates them to zero.

       The following features are unimplemented in mandoc:

       -   Bd -file file is unsupported for security reasons.
       -   Bd -filled does not adjust the right margin, but is an alias for Bd -ragged.
       -   Bd -literal does not use a literal font, but is an alias for Bd -unfilled.
       -   Bd -offset center and -offset right don't work.  Groff does not implement  centered  and  flush-right
           rendering either, but produces large indentations.

SEE ALSO

       man(1), mandoc(1), eqn(7), man(7), mandoc_char(7), roff(7), tbl(7)

       The  web  page  extended  documentation for the mdoc language: https://mandoc.bsd.lv/mdoc/ provides a few
       tutorial-style pages for beginners, an extensive style guide for  advanced  authors,  and  an  alphabetic
       index helping to choose the best macros for various kinds of content.

       The  manual  page  groff_mdoc(7):  https://man.voidlinux.org/groff_mdoc  contained in the “groff” package
       documents exactly the same language in a somewhat different style.

HISTORY

       The mdoc language first appeared as a troff macro package in 4.4BSD.  It was later significantly  updated
       by  Werner  Lemberg  and Ruslan Ermilov in groff-1.17.  The standalone implementation that is part of the
       mandoc(1) utility written by Kristaps Dzonsons appeared in OpenBSD 4.6.

AUTHORS

       The mdoc reference was written by Kristaps Dzonsons <kristaps@bsd.lv>.

Debian                                            July 29, 2021                                          MDOC(7)