Provided by: mandoc_1.14.4-1_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 arguments 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

       Pp, Lp   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:
       [functype]
       funcname
       [[argtype]
       argname]

       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 [name]

       Mt   “mailto” hyperlink: address

       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)

       Li                       typewriter font (literal) (>0 arguments)

       No                       return to roman font (normal) (no 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
       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
       Book title of an Rs block.  This macro may also be used in a non-bibliographic context when referring to
       book titles.

   %C
       Publication city or location of an Rs block.

   %D
       Publication date of an Rs block.  Recommended formats of arguments are month day, year or just year.

   %I
       Publisher or issuer name of an Rs block.

   %J
       Journal name of an Rs block.

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

   %O
       Optional information of an Rs block.

   %P
       Book or journal page number of an Rs block.

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

   %R
       Technical report name of an Rs block.

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

   %U
       URI of reference document.

   %V
       Volume number of an Rs block.

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

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

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

   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:

             -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
       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
       Encloses its arguments 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
       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
       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
       Begin a display block.  Its syntax is as follows:

             -type [-offset width] [-compact]

       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
       Change the font mode for a scoped block of text.  Its syntax is as follows:

             [-emphasis | -literal | -symbolic | Em | Li | Sy]

       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
       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:

       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
       Begin  a list.  Lists consist of items specified using the It macro, containing a head or a body or both.
       The list syntax is as follows:

             -type [-width val] [-offset val] [-compact] [HEAD ...]

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

       Examples:
             .Bo 1 ,
             .Dv BUFSIZ Bc

       See also Bq.

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

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

       See also Brq.

   Brq
       Encloses its arguments in curly braces.

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

       See also Bro.

   Bsx
       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
       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
       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
       Command  modifiers.  Typically used for fixed strings passed as arguments, unless Fl is more appropriate.
       Also useful when specifying configuration options or keys.

       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
             .Cm IdentityFile Pa ~/.ssh/id_rsa
             .Cm LogLevel Dv DEBUG

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

       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
       Document date for display in the page footer.  This is the mandatory first macro of any mdoc manual.  Its
       syntax is as follows:

       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
       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
       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
       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
       Document title for display in the page header.  This is the mandatory second macro of any mdoc file.  Its
       syntax is as follows:

             TITLE section [arch]

       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
       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
       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
       Close a scope started by Eo.  Its syntax is as follows:

       The TERM 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 Bl and It.

   Em
       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 Bf, Li, No, and Sy.

   En
       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
       An arbitrary enclosure.  Its syntax is as follows:

       The TERM argument is used as the enclosure head, for example, specifying \(lq will emulate Do.

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

       Examples:
             .Ev DISPLAY
             .Ev PATH

       See also Dv for general constants.

   Ex
       Insert a standard sentence regarding command exit values of 0 on success and >0 on failure.  This is most
       often used in section 1, 6, and 8 manual pages.  Its syntax is as follows:

       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
       Function argument or parameter.  Its syntax is as follows:

             "[argtype] [argname]" ...

       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
       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.

       Its syntax is as follows:

             #directive [argument ...]

       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
       Command-line  flag  or  option.   Used when listing arguments to command-line utilities.  Prints a fixed-
       width hyphen ‘-’ directly followed by each argument.  If no arguments are provided, a hyphen  is  printed
       followed by a space.  If the argument is a macro, a hyphen is prefixed to the subsequent macro output.

       Examples:
             .Fl R Op Fl H | L | P
             .Op Fl 1AaCcdFfgHhikLlmnopqRrSsTtux
             .Fl type Cm d Fl name Pa CVS
             .Fl Ar signal_number
             .Fl o Fl

       See also Cm.

   Fn
       A function name.  Its syntax is as follows:

             .Fn [functype] funcname [[argtype] argname]

       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
       Begin a function block.  This is a multi-line version of Fn.  Its syntax is as follows:

       Invocations usually occur in the following context:

             ...

       A Fo scope is closed by Fc.

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

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

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

   Ft
       A function type.  Its syntax is as follows:

       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
       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
       This macro is not implemented in mandoc(1).

       It was used to include the contents of a (header) file literally.  The syntax was:

             .Hf filename

   Ic
       Designate an internal or interactive command.  This is similar to Cm but  used  for  instructions  rather
       than values.

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

       Note  that  using Bd -literal or D1 is preferred for displaying code; the Ic macro is used when referring
       to specific instructions.

   In
       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
       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:

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

       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:

       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:

       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
       Specify a library.  The syntax is as follows:

       The  library  parameter  may  be  a system library, such as libz or libpam, in which case a small library
       description is printed next to the linker invocation; or a custom library, in which case the library name
       is printed in quotes.  This is most commonly  used  in  the  SYNOPSIS  section  as  described  in  MANUAL
       STRUCTURE.

       Examples:
             .Lb libz
             .Lb libmandoc

   Li
       Denotes text that should be in a literal font mode.  Note that this is a presentation term and should not
       be used for stylistically decorating technical terms.

       On terminal output devices, this is often indistinguishable from normal text.

       See also Bf, Em, No, and Sy.

   Lk
       Format a hyperlink.  Its syntax is as follows:

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

       See also Mt.

   Lp
       Synonym for Pp.

   Ms
       Display a mathematical symbol.  Its syntax is as follows:

       Examples:
             .Ms sigma
             .Ms aleph

   Mt
       Format a “mailto:” hyperlink.  Its syntax is as follows:

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

   Nd
       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
       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
       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, Li, 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
       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
       Multi-line version of Op.

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

   Op
       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
       Operating system version for display in the page footer.  This is the mandatory third macro of  any  mdoc
       file.  Its syntax is as follows:

       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
       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
       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
       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
       Removes the space between its argument and the following macro.  Its syntax is as follows:

             .Pf prefix macro arguments ...

       This is equivalent to:

             .No \&prefix Ns macro arguments ...

       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
       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) or lists (Bl)
       unless the -compact flag is given.

   Pq
       Parenthesised enclosure.

       See also Po.

   Qc
       Close quoted context opened by Qo.

   Ql
       In-line literal display.  This can for example be used for complete command invocations  and  for  multi-
       word  code fragments when more specific markup is not appropriate and an indented display is not desired.
       While mandoc(1) always encloses the arguments in single quotes, other formatters usually omit the  quotes
       on non-terminal output devices when the arguments have three or more characters.

       See also Dl and Bd -literal.

   Qo
       Multi-line version of Qq.

   Qq
       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
       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.  Its syntax is as follows:

       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
       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
       Switches the spacing mode for output generated from macros.  Its syntax is as follows:

       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
       Multi-line version of Sq.

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

       See also Dq, Qq, and So.

   Ss
       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
       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     IEEE Std 1003.1-1990 (“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.1b”)
          -p1003.1b       IEEE Std 1003.1b (“POSIX.1b”)
                          Real-time extensions.

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

          -p1003.1i-95    IEEE Std 1003.1i-1995 (“POSIX.1i”)
                          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         X/Open System Interfaces and Headers Issue 4, Version 2 (“XSH4.2”)

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

          -p1003.1g-2000
                          IEEE Std 1003.1g-2000 (“POSIX.1g”)
                          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 8802-3: 1989
                          Ethernet local area networks.

          -ieee1275-94    IEEE Std 1275-1994 (“Open Firmware”)
   Sx
       Reference  a  section  or  subsection in the same manual page.  The referenced section or subsection name
       must be identical to the enclosed argument, including whitespace.

       Examples:
             .Sx MANUAL STRUCTURE

       See also Sh and Ss.

   Sy
       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 Bf, Em, Li, and No.

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

   Tn
       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
       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
       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
       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
       Link to another manual ("cross-reference").  Its syntax is as follows:

       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

             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,

       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,

       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.

   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:

       -   Dd  with  non-standard  arguments  behaves  very strangely.  When there are three arguments, they are
           printed verbatim.  Any other number of arguments is replaced by the current  date,  but  without  any
           arguments the string “Epoch” is printed.
       -   Lk only accepts a single link-name argument; the remainder is misformatted.
       -   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.
       -   %C is not implemented (up to and including groff-1.22.2).
       -   ‘\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: http://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.

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 28, 2018                                          MDOC(7)