Provided by: groff_1.22.2-5_amd64 bug

NAME

     groff_mdoc — reference for groff's mdoc implementation

SYNOPSIS

     groff -mdoc file ...

DESCRIPTION

     A complete reference for writing UNIX manual pages with the -mdoc macro package; a
     content-based and domain-based formatting package for GNU troff(1).  Its predecessor, the
     -man(7) package, addressed page layout leaving the manipulation of fonts and other
     typesetting details to the individual author.  In -mdoc, page layout macros make up the page
     structure domain which consists of macros for titles, section headers, displays and lists -
     essentially items which affect the physical position of text on a formatted page.  In
     addition to the page structure domain, there are two more domains, the manual domain and the
     general text domain.  The general text domain is defined as macros which perform tasks such
     as quoting or emphasizing pieces of text.  The manual domain is defined as macros that are a
     subset of the day to day informal language used to describe commands, routines and related
     UNIX files.  Macros in the manual domain handle command names, command line arguments and
     options, function names, function parameters, pathnames, variables, cross references to
     other manual pages, and so on.  These domain items have value for both the author and the
     future user of the manual page.  Hopefully, the consistency gained across the manual set
     will provide easier translation to future documentation tools.

     Throughout the UNIX manual pages, a manual entry is simply referred to as a man page,
     regardless of actual length and without sexist intention.

GETTING STARTED

     The material presented in the remainder of this document is outlined as follows:

           1.   TROFF IDIOSYNCRASIES
                Macro Usage
                Passing Space Characters in an Argument
                Trailing Blank Space Characters
                Escaping Special Characters
                Other Possible Pitfalls

           2.   A MANUAL PAGE TEMPLATE

           3.   CONVENTIONS

           4.   TITLE MACROS

           5.   INTRODUCTION OF MANUAL AND GENERAL TEXT DOMAINS
                What's in a Name...
                General Syntax

           6.   MANUAL DOMAIN
                Addresses
                Author Name
                Arguments
                Configuration Declarations (Section Four Only)
                Command Modifiers
                Defined Variables
                Errno's
                Environment Variables
                Flags
                Function Declarations
                Function Types
                Functions (Library Routines)
                Function Arguments
                Return Values
                Exit Status
                Interactive Commands
                Library Names
                Literals
                Names
                Options
                Pathnames
                Standards
                Variable Types
                Variables
                Manual Page Cross References

           7.   GENERAL TEXT DOMAIN
                AT&T Macro
                BSD Macro
                NetBSD Macro
                FreeBSD Macro
                DragonFly Macro
                OpenBSD Macro
                BSD/OS Macro
                UNIX Macro
                Emphasis Macro
                Font Mode
                Enclosure and Quoting Macros
                No-Op or Normal Text Macro
                No-Space Macro
                Section Cross References
                Symbolics
                Mathematical Symbols
                References and Citations
                Trade Names (or Acronyms and Type Names)
                Extended Arguments

           8.   PAGE STRUCTURE DOMAIN
                Section Headers
                Subsection Headers
                Paragraphs and Line Spacing
                Keeps
                Examples and Displays
                Lists and Columns

           9.   MISCELLANEOUS MACROS

           10.  PREDEFINED STRINGS

           11.  DIAGNOSTICS

           12.  FORMATTING WITH GROFF, TROFF, AND NROFF

           13.  FILES

           14.  SEE ALSO

           15.  BUGS

TROFF IDIOSYNCRASIES

     The -mdoc package attempts to simplify the process of writing a man page.  Theoretically,
     one should not have to learn the tricky details of GNU troff(1) to use -mdoc; however, there
     are a few limitations which are unavoidable and best gotten out of the way.  And, too, be
     forewarned, this package is not fast.

   Macro Usage
     As in GNU troff(1), a macro is called by placing a ‘.’ (dot character) at the beginning of a
     line followed by the two-character (or three-character) name for the macro.  There can be
     space or tab characters between the dot and the macro name.  Arguments may follow the macro
     separated by spaces (but no tabs).  It is the dot character at the beginning of the line
     which causes GNU troff(1) to interpret the next two (or more) characters as a macro name.  A
     single starting dot followed by nothing is ignored.  To place a ‘.’ (dot character) at the
     beginning of an input line in some context other than a macro invocation, precede the ‘.’
     (dot) with the ‘\&’ escape sequence which translates literally to a zero-width space, and is
     never displayed in the output.

     In general, GNU troff(1) macros accept an unlimited number of arguments (contrary to other
     versions of troff which can't handle more than nine arguments).  In limited cases, arguments
     may be continued or extended on the next line (See Extended Arguments below).  Almost all
     macros handle quoted arguments (see Passing Space Characters in an Argument below).

     Most of the -mdoc general text domain and manual domain macros are special in that their
     argument lists are parsed for callable macro names.  This means an argument on the argument
     list which matches a general text or manual domain macro name (and which is defined to be
     callable) will be executed or called when it is processed.  In this case the argument,
     although the name of a macro, is not preceded by a ‘.’ (dot).  This makes it possible to
     nest macros; for example the option macro, ‘.Op’, may call the flag and argument macros,
     ‘Fl’ and ‘Ar’, to specify an optional flag with an argument:

           [-s bytes]  is produced by ‘.Op Fl s Ar bytes’

     To prevent a string from being interpreted as a macro name, precede the string with the
     escape sequence ‘\&’:

           [Fl s Ar bytes]  is produced by ‘.Op \&Fl s \&Ar bytes’

     Here the strings ‘Fl’ and ‘Ar’ are not interpreted as macros.  Macros whose argument lists
     are parsed for callable arguments are referred to as parsed and macros which may be called
     from an argument list are referred to as callable throughout this document.  This is a
     technical faux pas as almost all of the macros in -mdoc are parsed, but as it was cumbersome
     to constantly refer to macros as being callable and being able to call other macros, the
     term parsed has been used.

     In the following, we call an -mdoc macro which starts a line (with a leading dot) a command
     if this distinction is necessary.

   Passing Space Characters in an Argument
     Sometimes it is desirable to give as an argument a string containing one or more blank space
     characters, say, to specify arguments to commands which expect particular arrangement of
     items in the argument list.  Additionally, it makes -mdoc working faster.  For example, the
     function command ‘.Fn’ expects the first argument to be the name of a function and any
     remaining arguments to be function parameters.  As ANSI C stipulates the declaration of
     function parameters in the parenthesized parameter list, each parameter is guaranteed to be
     at minimum a two word string.  For example, int foo.

     There are two possible ways to pass an argument which contains an embedded space.  One way
     of passing a string containing blank spaces is to use the hard or unpaddable space character
     ‘\ ’, that is, a blank space preceded by the escape character ‘\’.  This method may be used
     with any macro but has the side effect of interfering with the adjustment of text over the
     length of a line.  Troff sees the hard space as if it were any other printable character and
     cannot split the string into blank or newline separated pieces as one would expect.  This
     method is useful for strings which are not expected to overlap a line boundary.  An
     alternative is to use ‘\~’, a paddable (i.e. stretchable), unbreakable space (this is a GNU
     troff(1) extension).  The second method is to enclose the string with double quotes.

     For example:

           fetch(char *str)  is created by ‘.Fn fetch char\ *str’

           fetch(char *str)  can also be created by ‘.Fn fetch "char *str"’

     If the ‘\’ before the space in the first example or double quotes in the second example were
     omitted, ‘.Fn’ would see three arguments, and the result would be:

           fetch(char, *str)

   Trailing Blank Space Characters
     Troff can be confused by blank space characters at the end of a line.  It is a wise
     preventive measure to globally remove all blank spaces from ⟨blank-space⟩⟨end-of-line⟩
     character sequences.  Should the need arise to use a blank character at the end of a line,
     it may be forced with an unpaddable space and the ‘\&’ escape character.  For example,
     ‘string\ \&’.

   Escaping Special Characters
     Special characters like the newline character ‘\n’ are handled by replacing the ‘\’ with
     ‘\e’ (e.g. ‘\en’) to preserve the backslash.

   Other Possible Pitfalls
     A warning is emitted when an empty input line is found outside of displays (see below).  Use
     ‘.sp’ instead.  (Well, it is even better to use -mdoc macros to avoid the usage of low-level
     commands.)

     Leading spaces will cause a break and are output directly.  Avoid this behaviour if
     possible.  Similarly, do not use more than one space character between words in an ordinary
     text line; contrary to other text formatters, they are not replaced with a single space.

     You can't pass ‘"’ directly as an argument.  Use ‘\*[q]’ (or ‘\*q’) instead.

     By default, troff(1) inserts two space characters after a punctuation mark closing a
     sentence; characters like ‘)’ or ‘'’ are treated transparently, not influencing the
     sentence-ending behaviour.  To change this, insert ‘\&’ before or after the dot:

           The
           .Ql .
           character.
           .Pp
           The
           .Ql \&.
           character.
           .Pp
           .No test .
           test
           .Pp
           .No test.
           test

     gives

           The ‘’.  character

           The ‘.’ character.

           test.  test

           test. test

     As can be seen in the first and third line, -mdoc handles punctuation characters specially
     in macro arguments.  This will be explained in section General Syntax below.  In the same
     way, you have to protect trailing full stops of abbreviations with a trailing zero-width
     space: ‘e.g.\&’.

     A comment in the source file of a man page can be either started with ‘.\"’ on a single
     line, ‘\"’ after some input, or ‘\#’ anywhere (the latter is a GNU troff(1) extension); the
     rest of such a line is ignored.

A MANUAL PAGE TEMPLATE

     The body of a man page is easily constructed from a basic template:

           .\" The following commands are required for all man pages.
           .Dd Month day, year
           .Dt DOCUMENT_TITLE [section number] [architecture/volume]
           .Os [OPERATING_SYSTEM] [version/release]
           .Sh NAME
           .Nm name
           .Nd one line description of name
           .\" This next command is for sections 2 and 3 only.
           .\" .Sh LIBRARY
           .Sh SYNOPSIS
           .Sh DESCRIPTION
           .\" The following commands should be uncommented and
           .\" used where appropriate.
           .\" .Sh IMPLEMENTATION NOTES
           .\" This next command is for sections 2, 3 and 9 function
           .\" return values only.
           .\" .Sh RETURN VALUES
           .\" This next command is for sections 1, 6, 7 and 8 only.
           .\" .Sh ENVIRONMENT
           .\" .Sh FILES
           .\" .Sh EXAMPLES
           .\" This next command is for sections 1, 6, 7, 8 and 9 only
           .\"     (command return values (to shell) and
           .\"     fprintf/stderr type diagnostics).
           .\" .Sh DIAGNOSTICS
           .\" .Sh COMPATIBILITY
           .\" This next command is for sections 2, 3 and 9 error
           .\"     and signal handling only.
           .\" .Sh ERRORS
           .\" .Sh SEE ALSO
           .\" .Sh STANDARDS
           .\" .Sh HISTORY
           .\" .Sh AUTHORS
           .\" .Sh BUGS

     The first items in the template are the commands ‘.Dd’, ‘.Dt’, and ‘.Os’; the document date,
     the operating system the man page or subject source is developed or modified for, and the
     man page title (in upper case) along with the section of the manual the page belongs in.
     These commands identify the page and are discussed below in TITLE MACROS.

     The remaining items in the template are section headers (.Sh); of which NAME, SYNOPSIS, and
     DESCRIPTION are mandatory.  The headers are discussed in PAGE STRUCTURE DOMAIN, after
     presentation of MANUAL DOMAIN.  Several content macros are used to demonstrate page layout
     macros; reading about content macros before page layout macros is recommended.

CONVENTIONS

     In the description of all macros below, optional arguments are put into brackets.  An
     ellipsis (‘...’) represents zero or more additional arguments.  Alternative values for a
     parameter are separated with ‘|’.  If there are alternative values for a mandatory
     parameter, braces are used (together with ‘|’) to enclose the value set.  Meta-variables are
     specified within angles.

     Example:

           .Xx ⟨foo⟩ {bar1 | bar2} [-test1 [-test2 | -test3]] ...

     Except stated explicitly, all macros are parsed and callable.

     Note that a macro takes effect up to the next nested macro.  For example, ‘.Ic foo Aq bar’
     doesn't produce ‘foo <bar>’ but ‘foo ⟨bar⟩’.  Consequently, a warning message is emitted for
     most commands if the first argument is a macro itself since it cancels the effect of the
     calling command completely.  Another consequence is that quoting macros never insert literal
     quotes; ‘foo <bar>’ has been produced by ‘.Ic "foo <bar>"’.

     Most macros have a default width value which can be used to specify a label width (-width)
     or offset (-offset) for the ‘.Bl’ and ‘.Bd’ macros.  It is recommended not to use this
     rather obscure feature to avoid dependencies on local modifications of the -mdoc package.

TITLE MACROS

     The title macros are part of the page structure domain but are presented first and
     separately for someone who wishes to start writing a man page yesterday.  Three header
     macros designate the document title or manual page title, the operating system, and the date
     of authorship.  These macros are called once at the very beginning of the document and are
     used to construct headers and footers only.

     .Dt [⟨document title⟩] [⟨section number⟩] [⟨volume⟩]
             The document title is the subject of the man page and must be in CAPITALS due to
             troff limitations.  If omitted, ‘UNTITLED’ is used.  The section number may be a
             number in the range 1, ..., 9 or ‘unass’, ‘draft’, or ‘paper’.  If it is specified,
             and no volume name is given, a default volume name is used.

             Under BSD, the following sections are defined:

             1   BSD General Commands Manual
             2   BSD System Calls Manual
             3   BSD Library Functions Manual
             4   BSD Kernel Interfaces Manual
             5   BSD File Formats Manual
             6   BSD Games Manual
             7   BSD Miscellaneous Information Manual
             8   BSD System Manager's Manual
             9   BSD Kernel Developer's Manual

             A volume name may be arbitrary or one of the following:

             USD     User's Supplementary Documents
             PS1     Programmer's Supplementary Documents
             AMD     Ancestral Manual Documents
             SMM     System Manager's Manual
             URM     User's Reference Manual
             PRM     Programmer's Manual
             KM      Kernel Manual
             IND     Manual Master Index
             LOCAL   Local Manual
             CON     Contributed Software Manual

             For compatibility, ‘MMI’ can be used for ‘IND’, and ‘LOC’ for ‘LOCAL’.  Values from
             the previous table will specify a new volume name.  If the third parameter is a
             keyword designating a computer architecture, its value is prepended to the default
             volume name as specified by the second parameter.  By default, the following
             architecture keywords are defined:

                   acorn26, acorn32, algor, alpha, amd64, amiga, amigappc, arc, arm, arm26,
                   arm32, armish, atari, aviion, beagle, bebox, cats, cesfic, cobalt, dreamcast,
                   emips, evbarm, evbmips, evbppc, evbsh3, ews4800mips, hp300, hp700, hpcarm,
                   hpcmips, hpcsh, hppa, hppa64, i386, ia64, ibmnws, iyonix, landisk, loongson,
                   luna68k, luna88k, m68k, mac68k, macppc, mips, mips64, mipsco, mmeye, mvme68k,
                   mvme88k, mvmeppc, netwinder, news68k, newsmips, next68k, ofppc, palm, pc532,
                   playstation2, pmax, pmppc, powerpc, prep, rs6000, sandpoint, sbmips, sgi,
                   sgimips, sh3, shark, socppc, solbourne, sparc, sparc64, sun2, sun3, tahoe,
                   vax, x68k, x86_64, xen, zaurus

             If the section number is neither a numeric expression in the range 1 to 9 nor one of
             the above described keywords, the third parameter is used verbatim as the volume
             name.

             In the following examples, the left (which is identical to the right) and the middle
             part of the manual page header strings are shown.  Note how ‘\&’ prevents the
             digit 7 from being a valid numeric expression.

                   .Dt FOO 7       ‘FOO(7)’ ‘BSD Miscellaneous Information Manual’
                   .Dt FOO 7 bar   ‘FOO(7)’ ‘BSD Miscellaneous Information Manual’
                   .Dt FOO \&7 bar
                                   ‘FOO(7)’ ‘bar’
                   .Dt FOO 2 i386  ‘FOO(2)’ ‘BSD/i386 System Calls Manual’
                   .Dt FOO "" bar  ‘FOO’ ‘bar’

             Local, OS-specific additions might be found in the file mdoc.local; look for strings
             named ‘volume-ds-XXX’ (for the former type) and ‘volume-as-XXX’ (for the latter
             type); ‘XXX’ then denotes the keyword to be used with the ‘.Dt’ macro.

             This macro is neither callable nor parsed.

     .Os [⟨operating system⟩] [⟨release⟩]
             If the first parameter is empty, the default ‘BSD’ is used.  This may be overridden
             in the local configuration file, mdoc.local.  In general, the name of the operating
             system should be the common acronym, e.g. BSD or ATT.  The release should be the
             standard release nomenclature for the system specified.  In the following table, the
             possible second arguments for some predefined operating systems are listed.  Similar
             to ‘.Dt’, local additions might be defined in mdoc.local; look for strings named
             ‘operating-system-XXX-YYY’, where ‘XXX’ is the acronym for the operating system and
             ‘YYY’ the release ID.

                   ATT        7th, 7, III, 3, V, V.2, V.3, V.4

                   BSD        3, 4, 4.1, 4.2, 4.3, 4.3t, 4.3T, 4.3r, 4.3R, 4.4

                   NetBSD     0.8, 0.8a, 0.9, 0.9a, 1.0, 1.0a, 1.1, 1.2, 1.2a, 1.2b, 1.2c, 1.2d,
                              1.2e, 1.3, 1.3a, 1.4, 1.4.1, 1.4.2, 1.4.3, 1.5, 1.5.1, 1.5.2,
                              1.5.3, 1.6, 1.6.1, 1.6.2, 1.6.3, 2.0, 2.0.1, 2.0.2, 2.0.3, 2.1,
                              3.0, 3.0.1, 3.0.2, 3.0.3, 3.1, 3.1.1, 4.0, 4.0.1, 5.0, 5.0.1,
                              5.0.2, 5.1, 6.0

                   FreeBSD    1.0, 1.1, 1.1.5, 1.1.5.1, 2.0, 2.0.5, 2.1, 2.1.5, 2.1.6, 2.1.7,
                              2.2, 2.2.1, 2.2.2, 2.2.5, 2.2.6, 2.2.7, 2.2.8, 3.0, 3.1, 3.2, 3.3,
                              3.4, 3.5, 4.0, 4.1, 4.1.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.6.2, 4.7,
                              4.8, 4.9, 4.10, 4.11, 5.0, 5.1, 5.2, 5.2.1, 5.3, 5.4, 5.5, 6.0,
                              6.1, 6.2, 6.3, 6.4, 7.0, 7.1, 7.2, 7.3, 8.0, 8.1, 8.2, 9.0

                   OpenBSD    2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2,
                              3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5,
                              4.6, 4.7, 4.8, 4.9, 5.0

                   DragonFly  1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, 1.8.1, 1.10, 1.12, 1.12.2,
                              2.0, 2.2, 2.4, 2.6, 2.8, 2.9, 2.9.1, 2.10, 2.10.1, 2.11

                   Darwin     8.0.0, 8.1.0, 8.2.0, 8.3.0, 8.4.0, 8.5.0, 8.6.0, 8.7.0, 8.8.0,
                              8.9.0, 8.10.0, 8.11.0, 9.0.0, 9.1.0, 9.2.0, 9.3.0, 9.4.0, 9.5.0,
                              9.6.0, 9.7.0, 9.8.0, 10.1.0, 10.2.0, 10.3.0, 10.4.0, 10.5.0,
                              10.6.0, 10.7.0, 11.0.0

             For ATT, an unknown second parameter will be replaced with the string UNIX; for the
             other predefined acronyms it will be ignored and a warning message emitted.
             Unrecognized arguments are displayed as given in the page footer.  For instance, a
             typical footer might be:

                   .Os BSD 4.3

             giving ‘4.3 Berkeley Distribution’, or for a locally produced set

                   .Os CS Department

             which will produce ‘CS Department’.

             If the ‘.Os’ macro is not present, the bottom left corner of the manual page will be
             ugly.

             This macro is neither callable nor parsed.

     .Dd [⟨month⟩ ⟨day⟩, ⟨year⟩]
             If ‘Dd’ has no arguments, ‘Epoch’ is used for the date string.  If it has exactly
             three arguments, they are concatenated, separated with unbreakable space:

                   .Dd January 25, 2001

             The month's name shall not be abbreviated.

             With any other number of arguments, the current date is used, ignoring the
             parameters.

             This macro is neither callable nor parsed.

INTRODUCTION OF MANUAL AND GENERAL TEXT DOMAINS

   What's in a Name...
     The manual domain macro names are derived from the day to day informal language used to
     describe commands, subroutines and related files.  Slightly different variations of this
     language are used to describe the three different aspects of writing a man page.  First,
     there is the description of -mdoc macro command usage.  Second is the description of a UNIX
     command with -mdoc macros, and third, the description of a command to a user in the verbal
     sense; that is, discussion of a command in the text of a man page.

     In the first case, troff(1) macros are themselves a type of command; the general syntax for
     a troff command is:

           .Xx argument1 argument2 ...

     ‘.Xx’ is a macro command, and anything following it are arguments to be processed.  In the
     second case, the description of a UNIX command using the content macros is a bit more
     involved; a typical SYNOPSIS command line might be displayed as:

           filter [-flag] ⟨infile⟩ ⟨outfile⟩

     Here, filter is the command name and the bracketed string -flag is a flag argument
     designated as optional by the option brackets.  In -mdoc terms, ⟨infile⟩ and ⟨outfile⟩ are
     called meta arguments; in this example, the user has to replace the meta expressions given
     in angle brackets with real file names.  Note that in this document meta arguments are used
     to describe -mdoc commands; in most man pages, meta variables are not specifically written
     with angle brackets.  The macros which formatted the above example:

           .Nm filter
           .Op Fl flag
           .Ao Ar infile Ac Ao Ar outfile Ac

     In the third case, discussion of commands and command syntax includes both examples above,
     but may add more detail.  The arguments ⟨infile⟩ and ⟨outfile⟩ from the example above might
     be referred to as operands or file arguments.  Some command line argument lists are quite
     long:

           make  [-eiknqrstv] [-D variable] [-d flags] [-f makefile] [-I directory] [-j max_jobs]
                 [variable=value] [target ...]

     Here one might talk about the command make and qualify the argument, makefile, as an
     argument to the flag, -f, or discuss the optional file operand target.  In the verbal
     context, such detail can prevent confusion, however the -mdoc package does not have a macro
     for an argument to a flag.  Instead the ‘Ar’ argument macro is used for an operand or file
     argument like target as well as an argument to a flag like variable.  The make command line
     was produced from:

           .Nm make
           .Op Fl eiknqrstv
           .Op Fl D Ar variable
           .Op Fl d Ar flags
           .Op Fl f Ar makefile
           .Op Fl I Ar directory
           .Op Fl j Ar max_jobs
           .Op Ar variable Ns = Ns Ar value
           .Bk
           .Op Ar target ...
           .Ek

     The ‘.Bk’ and ‘.Ek’ macros are explained in Keeps.

   General Syntax
     The manual domain and general text domain macros share a similar syntax with a few minor
     deviations; most notably, ‘.Ar’, ‘.Fl’, ‘.Nm’, and ‘.Pa’ differ only when called without
     arguments; and ‘.Fn’ and ‘.Xr’ impose an order on their argument lists.  All content macros
     are capable of recognizing and properly handling punctuation, provided each punctuation
     character is separated by a leading space.  If a command is given:

           .Ar sptr, ptr),

     The result is:

           sptr, ptr),

     The punctuation is not recognized and all is output in the font used by ‘.Ar’.  If the
     punctuation is separated by a leading white space:

           .Ar sptr , ptr ) ,

     The result is:

           sptr, ptr),

     The punctuation is now recognized and output in the default font distinguishing it from the
     argument strings.  To remove the special meaning from a punctuation character escape it with
     ‘\&’.

     The following punctuation characters are recognized by -mdoc:

               .         ,         :         ;         (
               )         [         ]         ?         !

     Troff is limited as a macro language, and has difficulty when presented with a string
     containing a member of the mathematical, logical or quotation set:

                 {+,-,/,*,%,<,>,<=,>=,=,==,&,`,',"}

     The problem is that troff may assume it is supposed to actually perform the operation or
     evaluation suggested by the characters.  To prevent the accidental evaluation of these
     characters, escape them with ‘\&’.  Typical syntax is shown in the first content macro
     displayed below, ‘.Ad’.

MANUAL DOMAIN

   Addresses
     The address macro identifies an address construct.

           Usage: .Ad ⟨address⟩ ...

                    .Ad addr1           addr1
                    .Ad addr1 .         addr1.
                    .Ad addr1 , file2   addr1, file2
                    .Ad f1 , f2 , f3 :  f1, f2, f3:
                    .Ad addr ) ) ,      addr)),

     The default width is 12n.

   Author Name
     The ‘.An’ macro is used to specify the name of the author of the item being documented, or
     the name of the author of the actual manual page.

           Usage: .An ⟨author name⟩ ...

                    .An "Joe Author"        Joe Author

                    .An "Joe Author" ,      Joe Author,

                    .An "Joe Author" Aq nobody@FreeBSD.org
                                            Joe Author <nobody@FreeBSD.org>

                    .An "Joe Author" ) ) ,  Joe Author)),

     The default width is 12n.

     In the AUTHORS section, the ‘.An’ command causes a line break allowing each new name to
     appear on its own line.  If this is not desirable,

           .An -nosplit

     call will turn this off.  To turn splitting back on, write

           .An -split

   Arguments
     The .Ar argument macro may be used whenever an argument is referenced.  If called without
     arguments, the ‘file ...’ string is output.

           Usage: .Ar [⟨argument⟩] ...

                    .Ar              file ...
                    .Ar file1        file1
                    .Ar file1 .      file1.
                    .Ar file1 file2  file1 file2
                    .Ar f1 f2 f3 :   f1 f2 f3:
                    .Ar file ) ) ,   file)),

     The default width is 12n.

   Configuration Declaration (Section Four Only)
     The ‘.Cd’ macro is used to demonstrate a config(8) declaration for a device interface in a
     section four manual.

           Usage: .Cd ⟨argument⟩ ...

                    .Cd "device le0 at scode?"  device le0 at scode?

     In the SYNOPSIS section a ‘.Cd’ command causes a line break before and after its arguments
     are printed.

     The default width is 12n.

   Command Modifiers
     The command modifier is identical to the ‘.Fl’ (flag) command with the exception that the
     ‘.Cm’ macro does not assert a dash in front of every argument.  Traditionally flags are
     marked by the preceding dash, however, some commands or subsets of commands do not use them.
     Command modifiers may also be specified in conjunction with interactive commands such as
     editor commands.  See Flags.

     The default width is 10n.

   Defined Variables
     A variable (or constant) which is defined in an include file is specified by the macro
     ‘.Dv’.

           Usage: .Dv ⟨defined variable⟩ ...

                    .Dv MAXHOSTNAMELEN  MAXHOSTNAMELEN
                    .Dv TIOCGPGRP )     TIOCGPGRP)

     The default width is 12n.

   Errno's
     The ‘.Er’ errno macro specifies the error return value for section 2, 3, and 9 library
     routines.  The second example below shows ‘.Er’ used with the ‘.Bq’ general text domain
     macro, as it would be used in a section two manual page.

           Usage: .Er ⟨errno type⟩ ...

                    .Er ENOENT      ENOENT
                    .Er ENOENT ) ;  ENOENT);
                    .Bq Er ENOTDIR  [ENOTDIR]

     The default width is 17n.

   Environment Variables
     The ‘.Ev’ macro specifies an environment variable.

           Usage: .Ev ⟨argument⟩ ...

                    .Ev DISPLAY        DISPLAY
                    .Ev PATH .         PATH.
                    .Ev PRINTER ) ) ,  PRINTER)),

     The default width is 15n.

   Flags
     The ‘.Fl’ macro handles command line flags.  It prepends a dash, ‘-’, to the flag.  For
     interactive command flags, which are not prepended with a dash, the ‘.Cm’ (command modifier)
     macro is identical, but without the dash.

           Usage: .Fl ⟨argument⟩ ...

                    .Fl          -
                    .Fl cfv      -cfv
                    .Fl cfv .    -cfv.
                    .Cm cfv .    cfv.
                    .Fl s v t    -s -v -t
                    .Fl - ,      --,
                    .Fl xyz ) ,  -xyz),
                    .Fl |        - |

     The ‘.Fl’ macro without any arguments results in a dash representing stdin/stdout.  Note
     that giving ‘.Fl’ a single dash will result in two dashes.

     The default width is 12n.

   Function Declarations
     The ‘.Fd’ macro is used in the SYNOPSIS section with section two or three functions.  It is
     neither callable nor parsed.

           Usage: .Fd ⟨argument⟩ ...

                    .Fd "#include <sys/types.h>"  #include <sys/types.h>

     In the SYNOPSIS section a ‘.Fd’ command causes a line break if a function has already been
     presented and a break has not occurred.  This leaves a nice vertical space in between the
     previous function call and the declaration for the next function.

     The ‘.In’ macro, while in the SYNOPSIS section, represents the #include statement, and is
     the short form of the above example.  It specifies the C header file as being included in a
     C program.  It also causes a line break.

     While not in the SYNOPSIS section, it represents the header file enclosed in angle brackets.

           Usage: .In ⟨header file⟩

                    .In stdio.h  #include <stdio.h>
                    .In stdio.h  <stdio.h>

   Function Types
     This macro is intended for the SYNOPSIS section.  It may be used anywhere else in the man
     page without problems, but its main purpose is to present the function type in kernel normal
     form for the SYNOPSIS of sections two and three (it causes a line break, allowing the
     function name to appear on the next line).

           Usage: .Ft ⟨type⟩ ...

                    .Ft struct stat  struct stat

   Functions (Library Routines)
     The ‘.Fn’ macro is modeled on ANSI C conventions.

           Usage: .Fn ⟨function⟩ [⟨parameter⟩] ...

                    .Fn getchar              getchar()
                    .Fn strlen ) ,           strlen()),
                    .Fn align "char *ptr" ,  align(char *ptr),

     Note that any call to another macro signals the end of the ‘.Fn’ call (it will insert a
     closing parenthesis at that point).

     For functions with many parameters (which is rare), the macros ‘.Fo’ (function open) and
     ‘.Fc’ (function close) may be used with ‘.Fa’ (function argument).

     Example:

           .Ft int
           .Fo res_mkquery
           .Fa "int op"
           .Fa "char *dname"
           .Fa "int class"
           .Fa "int type"
           .Fa "char *data"
           .Fa "int datalen"
           .Fa "struct rrec *newrr"
           .Fa "char *buf"
           .Fa "int buflen"
           .Fc

     Produces:

           int res_mkquery(int op, char *dname, int class, int type, char *data, int datalen,
           struct rrec *newrr, char *buf, int buflen)

     In the SYNOPSIS section, the function will always begin at the beginning of line.  If there
     is more than one function presented in the SYNOPSIS section and a function type has not been
     given, a line break will occur, leaving a nice vertical space between the current function
     name and the one prior.

     The default width values of ‘.Fn’ and ‘.Fo’ are 12n and 16n, respectively.

   Function Arguments
     The ‘.Fa’ macro is used to refer to function arguments (parameters) outside of the SYNOPSIS
     section of the manual or inside the SYNOPSIS section if the enclosure macros ‘.Fo’ and ‘.Fc’
     instead of ‘.Fn’ are used.  ‘.Fa’ may also be used to refer to structure members.

           Usage: .Fa ⟨function argument⟩ ...

                    .Fa d_namlen ) ) ,  d_namlen)),
                    .Fa iov_len         iov_len

     The default width is 12n.

   Return Values
     The ‘.Rv’ macro generates text for use in the RETURN VALUES section.

           Usage: .Rv [-std] [⟨function⟩ ...]

     For example, ‘.Rv -std atexit’ produces:

           The atexit() function returns the value 0 if successful; otherwise the value -1 is
           returned and the global variable errno is set to indicate the error.

     The -std option is valid only for manual page sections 2 and 3.  Currently, this macro does
     nothing if used without the -std flag.

   Exit Status
     The ‘.Ex’ macro generates text for use in the DIAGNOSTICS section.

           Usage: .Ex [-std] [⟨utility⟩ ...]

     For example, ‘.Ex -std cat’ produces:

           The cat utility exits 0 on success, and >0 if an error occurs.

     The -std option is valid only for manual page sections 1, 6 and 8.  Currently, this macro
     does nothing if used without the -std flag.

   Interactive Commands
     The ‘.Ic’ macro designates an interactive or internal command.

           Usage: .Ic ⟨argument⟩ ...

                    .Ic :wq                :wq
                    .Ic "do while {...}"   do while {...}
                    .Ic setenv , unsetenv  setenv, unsetenv

     The default width is 12n.

   Library Names
     The ‘.Lb’ macro is used to specify the library where a particular function is compiled in.

           Usage: .Lb ⟨argument⟩ ...

     Available arguments to ‘.Lb’ and their results are:

           libarchive     Reading and Writing Streaming Archives Library (libarchive, -larchive)
           libarm         ARM Architecture Library (libarm, -larm)
           libarm32       ARM32 Architecture Library (libarm32, -larm32)
           libbluetooth   Bluetooth Library (libbluetooth, -lbluetooth)
           libbsm         Basic Security Module Library (libbsm, -lbsm)
           libc           Standard C Library (libc, -lc)
           libc_r         Reentrant C Library (libc_r, -lc_r)
           libcalendar    Calendar Arithmetic Library (libcalendar, -lcalendar)
           libcam         Common Access Method User Library (libcam, -lcam)
           libcdk         Curses Development Kit Library (libcdk, -lcdk)
           libcipher      FreeSec Crypt Library (libcipher, -lcipher)
           libcompat      Compatibility Library (libcompat, -lcompat)
           libcrypt       Crypt Library (libcrypt, -lcrypt)
           libcurses      Curses Library (libcurses, -lcurses)
           libdevinfo     Device and Resource Information Utility Library (libdevinfo, -ldevinfo)
           libdevstat     Device Statistics Library (libdevstat, -ldevstat)
           libdisk        Interface to Slice and Partition Labels Library (libdisk, -ldisk)
           libdwarf       DWARF Access Library (libdwarf, -ldwarf)
           libedit        Command Line Editor Library (libedit, -ledit)
           libelf         ELF Access Library (libelf, -lelf)
           libevent       Event Notification Library (libevent, -levent)
           libfetch       File Transfer Library for URLs (libfetch, -lfetch)
           libform        Curses Form Library (libform, -lform)
           libgeom        Userland API Library for kernel GEOM subsystem (libgeom, -lgeom)
           libgpib        General-Purpose Instrument Bus (GPIB) library (libgpib, -lgpib)
           libi386        i386 Architecture Library (libi386, -li386)
           libintl        Internationalized Message Handling Library (libintl, -lintl)
           libipsec       IPsec Policy Control Library (libipsec, -lipsec)
           libipx         IPX Address Conversion Support Library (libipx, -lipx)
           libiscsi       iSCSI protocol library (libiscsi, -liscsi)
           libjail        Jail Library (libjail, -ljail)
           libkiconv      Kernel side iconv library (libkiconv, -lkiconv)
           libkse         N:M Threading Library (libkse, -lkse)
           libkvm         Kernel Data Access Library (libkvm, -lkvm)
           libm           Math Library (libm, -lm)
           libm68k        m68k Architecture Library (libm68k, -lm68k)
           libmagic       Magic Number Recognition Library (libmagic, -lmagic)
           libmd          Message Digest (MD4, MD5, etc.) Support Library (libmd, -lmd)
           libmemstat     Kernel Memory Allocator Statistics Library (libmemstat, -lmemstat)
           libmenu        Curses Menu Library (libmenu, -lmenu)
           libnetgraph    Netgraph User Library (libnetgraph, -lnetgraph)
           libnetpgp      Netpgp signing, verification, encryption and decryption (libnetpgp,
                          -lnetpgp)
           libossaudio    OSS Audio Emulation Library (libossaudio, -lossaudio)
           libpam         Pluggable Authentication Module Library (libpam, -lpam)
           libpcap        Packet Capture Library (libpcap, -lpcap)
           libpci         PCI Bus Access Library (libpci, -lpci)
           libpmc         Performance Counters Library (libpmc, -lpmc)
           libposix       POSIX Compatibility Library (libposix, -lposix)
           libprop        Property Container Object Library (libprop, -lprop)
           libpthread     POSIX Threads Library (libpthread, -lpthread)
           libpuffs       puffs Convenience Library (libpuffs, -lpuffs)
           librefuse      File System in Userspace Convenience Library (librefuse, -lrefuse)
           libresolv      DNS Resolver Library (libresolv, -lresolv)
           librpcsec_gss  RPC GSS-API Authentication Library (librpcsec_gss, -lrpcsec_gss)
           librpcsvc      RPC Service Library (librpcsvc, -lrpcsvc)
           librt          POSIX Real-time Library (librt, -lrt)
           libsdp         Bluetooth Service Discovery Protocol User Library (libsdp, -lsdp)
           libssp         Buffer Overflow Protection Library (libssp, -lssp)
           libSystem      System Library (libSystem, -lSystem)
           libtermcap     Termcap Access Library (libtermcap, -ltermcap)
           libterminfo    Terminal Information Library (libterminfo, -lterminfo)
           libthr         1:1 Threading Library (libthr, -lthr)
           libufs         UFS File System Access Library (libufs, -lufs)
           libugidfw      File System Firewall Interface Library (libugidfw, -lugidfw)
           libulog        User Login Record Library (libulog, -lulog)
           libusbhid      USB Human Interface Devices Library (libusbhid, -lusbhid)
           libutil        System Utilities Library (libutil, -lutil)
           libvgl         Video Graphics Library (libvgl, -lvgl)
           libx86_64      x86_64 Architecture Library (libx86_64, -lx86_64)
           libz           Compression Library (libz, -lz)

     Local, OS-specific additions might be found in the file mdoc.local; look for strings named
     ‘str-Lb-XXX’.  ‘XXX’ then denotes the keyword to be used with the ‘.Lb’ macro.

     In the LIBRARY section an ‘.Lb’ command causes a line break before and after its arguments
     are printed.

   Literals
     The ‘.Li’ literal macro may be used for special characters, variable constants, etc. -
     anything which should be displayed as it would be typed.

           Usage: .Li ⟨argument⟩ ...

                    .Li \en          \n
                    .Li M1 M2 M3 ;   M1 M2 M3;
                    .Li cntrl-D ) ,  cntrl-D),
                    .Li 1024 ...     1024 ...

     The default width is 16n.

   Names
     The ‘.Nm’ macro is used for the document title or subject name.  It has the peculiarity of
     remembering the first argument it was called with, which should always be the subject name
     of the page.  When called without arguments, ‘.Nm’ regurgitates this initial name for the
     sole purpose of making less work for the author.  ‘.Nm’ causes a line break within the
     SYNOPSIS section.

     Note: A section two or three document function name is addressed with the ‘.Nm’ in the NAME
     section, and with ‘.Fn’ in the SYNOPSIS and remaining sections.  For interactive commands,
     such as the ‘while’ command keyword in csh(1), the ‘.Ic’ macro should be used.  While ‘.Ic’
     is nearly identical to ‘.Nm’, it can not recall the first argument it was invoked with.

           Usage: .Nm [⟨argument⟩] ...

                    .Nm groff_mdoc  groff_mdoc
                    .Nm \-mdoc      -mdoc
                    .Nm foo ) ) ,   foo)),
                    .Nm :           groff_mdoc:

     The default width is 10n.

   Options
     The ‘.Op’ macro places option brackets around any remaining arguments on the command line,
     and places any trailing punctuation outside the brackets.  The macros ‘.Oo’ and ‘.Oc’ (which
     produce an opening and a closing option bracket respectively) may be used across one or more
     lines or to specify the exact position of the closing parenthesis.

           Usage: .Op [⟨option⟩] ...

                    .Op                                []
                    .Op Fl k                           [-k]
                    .Op Fl k ) .                       [-k]).
                    .Op Fl k Ar kookfile               [-k kookfile]
                    .Op Fl k Ar kookfile ,             [-k kookfile],
                    .Op Ar objfil Op Ar corfil         [objfil [corfil]]
                    .Op Fl c Ar objfil Op Ar corfil ,  [-c objfil [corfil]],
                    .Op word1 word2                    [word1 word2]
                    .Li .Op Oo Ao option Ac Oc ...     .Op [⟨option⟩] ...

     Here a typical example of the ‘.Oo’ and ‘.Oc’ macros:

           .Oo
           .Op Fl k Ar kilobytes
           .Op Fl i Ar interval
           .Op Fl c Ar count
           .Oc

     Produces:

           [[-k kilobytes] [-i interval] [-c count]]

     The default width values of ‘.Op’ and ‘.Oo’ are 14n and 10n, respectively.

   Pathnames
     The ‘.Pa’ macro formats path or file names.  If called without arguments, the ‘~’ string is
     output, which represents the current user's home directory.

           Usage: .Pa [⟨pathname⟩] ...

                    .Pa                    ~
                    .Pa /usr/share         /usr/share
                    .Pa /tmp/fooXXXXX ) .  /tmp/fooXXXXX).

     The default width is 32n.

   Standards
     The ‘.St’ macro replaces standard abbreviations with their formal names.

           Usage: .St ⟨abbreviation⟩ ...

     Available pairs for “Abbreviation/Formal Name” are:

     ANSI/ISO C

           -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”)
           -isoC-99        ISO/IEC 9899:1999 (“ISO C99”)
           -isoC-2011      ISO/IEC 9899:2011 (“ISO C11”)

     POSIX Part 1: System API

           -iso9945-1-90   ISO/IEC 9945-1:1990 (“POSIX.1”)
           -iso9945-1-96   ISO/IEC 9945-1:1996 (“POSIX.1”)
           -p1003.1        IEEE Std 1003.1 (“POSIX.1”)
           -p1003.1-88     IEEE Std 1003.1-1988 (“POSIX.1”)
           -p1003.1-90     ISO/IEC 9945-1:1990 (“POSIX.1”)
           -p1003.1-96     ISO/IEC 9945-1:1996 (“POSIX.1”)
           -p1003.1b-93    IEEE Std 1003.1b-1993 (“POSIX.1”)
           -p1003.1c-95    IEEE Std 1003.1c-1995 (“POSIX.1”)
           -p1003.1g-2000  IEEE Std 1003.1g-2000 (“POSIX.1”)
           -p1003.1i-95    IEEE Std 1003.1i-1995 (“POSIX.1”)
           -p1003.1-2001   IEEE Std 1003.1-2001 (“POSIX.1”)
           -p1003.1-2004   IEEE Std 1003.1-2004 (“POSIX.1”)
           -p1003.1-2008   IEEE Std 1003.1-2008 (“POSIX.1”)

     POSIX Part 2: Shell and Utilities

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

     X/Open

           -susv2          Version 2 of the Single UNIX Specification (“SUSv2”)
           -susv3          Version 3 of the Single UNIX Specification (“SUSv3”)
           -svid4          System V Interface Definition, Fourth Edition (“SVID4”)
           -xbd5           X/Open Base Definitions Issue 5 (“XBD5”)
           -xcu5           X/Open Commands and Utilities Issue 5 (“XCU5”)
           -xcurses4.2     X/Open Curses Issue 4, Version 2 (“XCURSES4.2”)
           -xns5           X/Open Networking Services Issue 5 (“XNS5”)
           -xns5.2         X/Open Networking Services Issue 5.2 (“XNS5.2”)
           -xpg3           X/Open Portability Guide Issue 3 (“XPG3”)
           -xpg4           X/Open Portability Guide Issue 4 (“XPG4”)
           -xpg4.2         X/Open Portability Guide Issue 4, Version 2 (“XPG4.2”)
           -xsh5           X/Open System Interfaces and Headers Issue 5 (“XSH5”)

     Miscellaneous

           -ieee754        IEEE Std 754-1985
           -iso8802-3      ISO/IEC 8802-3:1989

   Variable Types
     The ‘.Vt’ macro may be used whenever a type is referenced.  In the SYNOPSIS section, it
     causes a line break (useful for old style variable declarations).

           Usage: .Vt ⟨type⟩ ...

                    .Vt extern char *optarg ;  extern char *optarg;
                    .Vt FILE *                 FILE *

   Variables
     Generic variable reference.

           Usage: .Va ⟨variable⟩ ...

                    .Va count             count
                    .Va settimer ,        settimer,
                    .Va "int *prt" ) :    int *prt):
                    .Va "char s" ] ) ) ,  char s])),

     The default width is 12n.

   Manual Page Cross References
     The ‘.Xr’ macro expects the first argument to be a manual page name.  The optional second
     argument, if a string (defining the manual section), is put into parentheses.

           Usage: .Xr ⟨man page name⟩ [⟨section⟩] ...

                    .Xr mdoc        mdoc
                    .Xr mdoc ,      mdoc,
                    .Xr mdoc 7      mdoc(7)
                    .Xr xinit 1x ;  xinit(1x);

     The default width is 10n.

GENERAL TEXT DOMAIN

   AT&T Macro
           Usage: .At [⟨version⟩] ...

                    .At       AT&T UNIX
                    .At v6 .  Version 6 AT&T UNIX.

     The following values for ⟨version⟩ are possible:

           32v, v1, v2, v3, v4, v5, v6, v7, V, V.1, V.2, V.3, V.4

   BSD Macro
           Usage: .Bx {-alpha | -beta | -devel} ...
                  .Bx [⟨version⟩ [⟨release⟩]] ...

                    .Bx         BSD
                    .Bx 4.3 .   4.3BSD.
                    .Bx -devel  BSD (currently under development)

     ⟨version⟩ will be prepended to the string ‘BSD’.  The following values for ⟨release⟩ are
     possible:

           Reno, reno, Tahoe, tahoe, Lite, lite, Lite2, lite2

   NetBSD Macro
           Usage: .Nx [⟨version⟩] ...

                    .Nx        NetBSD
                    .Nx 1.4 .  NetBSD 1.4.

     For possible values of ⟨version⟩ see the description of the ‘.Os’ command above in section
     TITLE MACROS.

   FreeBSD Macro
           Usage: .Fx [⟨version⟩] ...

                    .Fx        FreeBSD
                    .Fx 2.2 .  FreeBSD 2.2.

     For possible values of ⟨version⟩ see the description of the ‘.Os’ command above in section
     TITLE MACROS.

   DragonFly Macro
           Usage: .Dx [⟨version⟩] ...

                    .Dx        DragonFly
                    .Dx 1.4 .  DragonFly 1.4.

     For possible values of ⟨version⟩ see the description of the ‘.Os’ command above in section
     TITLE MACROS.

   OpenBSD Macro
           Usage: .Ox [⟨version⟩] ...

                    .Ox 1.0  OpenBSD 1.0

   BSD/OS Macro
           Usage: .Bsx [⟨version⟩] ...

                    .Bsx 1.0  BSD/OS 1.0

   UNIX Macro
           Usage: .Ux ...

                    .Ux  UNIX

   Emphasis Macro
     Text may be stressed or emphasized with the ‘.Em’ macro.  The usual font for emphasis is
     italic.

           Usage: .Em ⟨argument⟩ ...

                    .Em does not          does not
                    .Em exceed 1024 .     exceed 1024.
                    .Em vide infra ) ) ,  vide infra)),

     The default width is 10n.

   Font Mode
     The ‘.Bf’ font mode must be ended with the ‘.Ef’ macro (the latter takes no arguments).
     Font modes may be nested within other font modes.

     ‘.Bf’ has the following syntax:

           .Bf ⟨font mode⟩

     ⟨font mode⟩ must be one of the following three types:

           Em | -emphasis  Same as if the ‘.Em’ macro was used for the entire block of text.
           Li | -literal   Same as if the ‘.Li’ macro was used for the entire block of text.
           Sy | -symbolic  Same as if the ‘.Sy’ macro was used for the entire block of text.

     Both macros are neither callable nor parsed.

   Enclosure and Quoting Macros
     The concept of enclosure is similar to quoting.  The object being to enclose one or more
     strings between a pair of characters like quotes or parentheses.  The terms quoting and
     enclosure are used interchangeably throughout this document.  Most of the one-line enclosure
     macros end in small letter ‘q’ to give a hint of quoting, but there are a few
     irregularities.  For each enclosure macro there is also a pair of open and close macros
     which end in small letters ‘o’ and ‘c’ respectively.

     Quote   Open   Close   Function                  Result
     .Aq     .Ao    .Ac     Angle Bracket Enclosure   <string>
     .Bq     .Bo    .Bc     Bracket Enclosure         [string]

     .Brq    .Bro   .Brc    Brace Enclosure           {string}
     .Dq     .Do    .Dc     Double Quote              "string"
     .Eq     .Eo    .Ec     Enclose String (in XX)    XXstring
     .Pq     .Po    .Pc     Parenthesis Enclosure     (string)
     .Ql                    Quoted Literal            “string” or string
     .Qq     .Qo    .Qc     Straight Double Quote     "string"
     .Sq     .So    .Sc     Single Quote              'string'

     All macros ending with ‘q’ and ‘o’ have a default width value of 12n.

     .Eo, .Ec  These macros expect the first argument to be the opening and closing strings
               respectively.

     .Es, .En  Due to the nine-argument limit in the original troff program two other macros have
               been implemented which are now rather obsolete: ‘.Es’ takes the first and second
               parameter as the left and right enclosure string, which are then used to enclose
               the arguments of ‘.En’.  The default width value is 12n for both macros.

     .Eq       The first and second arguments of this macro are the opening and closing strings
               respectively, followed by the arguments to be enclosed.

     .Ql       The quoted literal macro behaves differently in troff and nroff mode.  If
               formatted with nroff, a quoted literal is always quoted.  If formatted with troff,
               an item is only quoted if the width of the item is less than three constant width
               characters.  This is to make short strings more visible where the font change to
               literal (constant width) is less noticeable.

               The default width is 16n.

     .Pf       The prefix macro suppresses the whitespace between its first and second argument:

                     .Pf ( Fa name2  (name2

               The default width is 12n.

               The ‘.Ns’ macro (see below) performs the analogous suffix function.

     .Ap       The ‘.Ap’ macro inserts an apostrophe and exits any special text modes, continuing
               in ‘.No’ mode.

     Examples of quoting:

           .Aq                      ⟨⟩
           .Aq Pa ctype.h ) ,       ⟨ctype.h⟩),
           .Bq                      []
           .Bq Em Greek , French .  [Greek, French].
           .Dq                      “”
           .Dq string abc .         “string abc”.
           .Dq ´^[A-Z]´             “´^[A-Z]´”
           .Ql man mdoc             ‘man mdoc’
           .Qq                      ""
           .Qq string ) ,           "string"),
           .Qq string Ns ),         "string),"
           .Sq                      ‘’
           .Sq string               ‘string’
           .Em or Ap ing            or'ing

     For a good example of nested enclosure macros, see the ‘.Op’ option macro.  It was created
     from the same underlying enclosure macros as those presented in the list above.  The ‘.Xo’
     and ‘.Xc’ extended argument list macros are discussed below.

   No-Op or Normal Text Macro
     The ‘.No’ macro can be used in a macro command line for parameters which should not be
     formatted.  Be careful to add ‘\&’ to the word ‘No’ if you really want that English word
     (and not the macro) as a parameter.

           Usage: .No ⟨argument⟩ ...

                    .No test Ta with Ta tabs  test     with     tabs

     The default width is 12n.

   No-Space Macro
     The ‘.Ns’ macro suppresses insertion of a space between the current position and its first
     parameter.  For example, it is useful for old style argument lists where there is no space
     between the flag and argument:

           Usage: ... ⟨argument⟩ Ns [⟨argument⟩] ...
                  .Ns ⟨argument⟩ ...

                    .Op Fl I Ns Ar directory  [-Idirectory]

     Note: The ‘.Ns’ macro always invokes the ‘.No’ macro after eliminating the space unless
     another macro name follows it.  If used as a command (i.e., the second form above in the
     ‘Usage’ line), ‘.Ns’ is identical to ‘.No’.

   Section Cross References
     The ‘.Sx’ macro designates a reference to a section header within the same document.

           Usage: .Sx ⟨section reference⟩ ...

                    .Sx FILES  FILES

     The default width is 16n.

   Symbolics
     The symbolic emphasis macro is generally a boldface macro in either the symbolic sense or
     the traditional English usage.

           Usage: .Sy ⟨symbol⟩ ...

                    .Sy Important Notice  Important Notice

     The default width is 6n.

   Mathematical Symbols
     Use this macro for mathematical symbols and similar things.

           Usage: .Ms ⟨math symbol⟩ ...

                    .Ms sigma  sigma

     The default width is 6n.

   References and Citations
     The following macros make a modest attempt to handle references.  At best, the macros make
     it convenient to manually drop in a subset of refer(1) style references.

           .Rs     Reference start (does not take arguments).  Causes a line break in the SEE
                   ALSO section and begins collection of reference information until the
                   reference end macro is read.
           .Re     Reference end (does not take arguments).  The reference is printed.
           .%A     Reference author name; one name per invocation.
           .%B     Book title.
           .%C     City/place (not implemented yet).
           .%D     Date.
           .%I     Issuer/publisher name.
           .%J     Journal name.
           .%N     Issue number.
           .%O     Optional information.
           .%P     Page number.
           .%Q     Corporate or foreign author.
           .%R     Report name.
           .%T     Title of article.
           .%U     Optional hypertext reference.
           .%V     Volume.

     Macros beginning with ‘%’ are not callable but accept multiple arguments in the usual way.
     Only the ‘.Tn’ macro is handled properly as a parameter; other macros will cause strange
     output.  ‘.%B’ and ‘.%T’ can be used outside of the ‘.Rs/.Re’ environment.

     Example:

           .Rs
           .%A "Matthew Bar"
           .%A "John Foo"
           .%T "Implementation Notes on foobar(1)"
           .%R "Technical Report ABC-DE-12-345"
           .%Q "Drofnats College, Nowhere"
           .%D "April 1991"
           .Re

     produces

           Matthew Bar and John Foo, Implementation Notes on foobar(1), Technical Report ABC-
           DE-12-345, Drofnats College, Nowhere, April 1991.

   Trade Names (or Acronyms and Type Names)
     The trade name macro prints its arguments in a smaller font.  Its intended use is to imitate
     a small caps fonts for uppercase acronyms.

           Usage: .Tn ⟨symbol⟩ ...

                    .Tn DEC    DEC
                    .Tn ASCII  ASCII

     The default width is 10n.

   Extended Arguments
     The .Xo and .Xc macros allow one to extend an argument list on a macro boundary for the
     ‘.It’ macro (see below).  Note that .Xo and .Xc are implemented similarly to all other
     macros opening and closing an enclosure (without inserting characters, of course).  This
     means that the following is true for those macros also.

     Here is an example of ‘.Xo’ using the space mode macro to turn spacing off:

           .Sm off
           .It Xo Sy I Ar operation
           .No \en Ar count No \en
           .Xc
           .Sm on

     produces

           Ioperation\ncount\n

     Another one:

           .Sm off
           .It Cm S No / Ar old_pattern Xo
           .No / Ar new_pattern
           .No / Op Cm g
           .Xc
           .Sm on

     produces

           S/old_pattern/new_pattern/[g]

     Another example of ‘.Xo’ and enclosure macros: Test the value of a variable.

           .It Xo
           .Ic .ifndef
           .Oo \&! Oc Ns Ar variable Oo
           .Ar operator variable ...
           .Oc Xc

     produces

           .ifndef [!]variable [operator variable ...]

PAGE STRUCTURE DOMAIN

   Section Headers
     The following ‘.Sh’ section header macros are required in every man page.  The remaining
     section headers are recommended at the discretion of the author writing the manual page.
     The ‘.Sh’ macro is parsed but not generally callable.  It can be used as an argument in a
     call to ‘.Sh’ only; it then reactivates the default font for ‘.Sh’.

     The default width is 8n.

     .Sh NAME           The ‘.Sh NAME’ macro is mandatory.  If not specified, headers, footers
                        and page layout defaults will not be set and things will be rather
                        unpleasant.  The NAME section consists of at least three items.  The
                        first is the ‘.Nm’ name macro naming the subject of the man page.  The
                        second is the name description macro, ‘.Nd’, which separates the subject
                        name from the third item, which is the description.  The description
                        should be the most terse and lucid possible, as the space available is
                        small.

                        ‘.Nd’ first prints ‘-’, then all its arguments.

     .Sh LIBRARY        This section is for section two and three function calls.  It should
                        consist of a single ‘.Lb’ macro call; see Library Names.

     .Sh SYNOPSIS       The SYNOPSIS section describes the typical usage of the subject of a man
                        page.  The macros required are either ‘.Nm’, ‘.Cd’, or ‘.Fn’ (and
                        possibly ‘.Fo’, ‘.Fc’, ‘.Fd’, and ‘.Ft’).  The function name macro ‘.Fn’
                        is required for manual page sections 2 and 3; the command and general
                        name macro ‘.Nm’ is required for sections 1, 5, 6, 7, and 8.  Section 4
                        manuals require a ‘.Nm’, ‘.Fd’ or a ‘.Cd’ configuration device usage
                        macro.  Several other macros may be necessary to produce the synopsis
                        line as shown below:

                              cat [-benstuv] [-] file ...

                        The following macros were used:

                              .Nm cat
                              .Op Fl benstuv
                              .Op Fl
                              .Ar

     .Sh DESCRIPTION    In most cases the first text in the DESCRIPTION section is a brief
                        paragraph on the command, function or file, followed by a lexical list of
                        options and respective explanations.  To create such a list, the ‘.Bl’
                        (begin list), ‘.It’ (list item) and ‘.El’ (end list) macros are used (see
                        Lists and Columns below).

     .Sh IMPLEMENTATION NOTES
                        Implementation specific information should be placed here.

     .Sh RETURN VALUES  Sections 2, 3 and 9 function return values should go here.  The ‘.Rv’
                        macro may be used to generate text for use in the RETURN VALUES section
                        for most section 2 and 3 library functions; see Return Values.

     The following ‘.Sh’ section headers are part of the preferred manual page layout and must be
     used appropriately to maintain consistency.  They are listed in the order in which they
     would be used.

     .Sh ENVIRONMENT    The ENVIRONMENT section should reveal any related environment variables
                        and clues to their behavior and/or usage.

     .Sh FILES          Files which are used or created by the man page subject should be listed
                        via the ‘.Pa’ macro in the FILES section.

     .Sh EXAMPLES       There are several ways to create examples.  See the EXAMPLES section
                        below for details.

     .Sh DIAGNOSTICS    Diagnostic messages from a command should be placed in this section.  The
                        ‘.Ex’ macro may be used to generate text for use in the DIAGNOSTICS
                        section for most section 1, 6 and 8 commands; see Exit Status.

     .Sh COMPATIBILITY  Known compatibility issues (e.g. deprecated options or parameters) should
                        be listed here.

     .Sh ERRORS         Specific error handling, especially from library functions (man page
                        sections 2, 3, and 9) should go here.  The ‘.Er’ macro is used to specify
                        an error (errno).

     .Sh SEE ALSO       References to other material on the man page topic and cross references
                        to other relevant man pages should be placed in the SEE ALSO section.
                        Cross references are specified using the ‘.Xr’ macro.  Currently refer(1)
                        style references are not accommodated.

                        It is recommended that the cross references are sorted on the section
                        number, then alphabetically on the names within a section, and placed in
                        that order and comma separated.  Example:

                        ls(1), ps(1), group(5), passwd(5)

     .Sh STANDARDS      If the command, library function or file adheres to a specific
                        implementation such as IEEE Std 1003.2 (“POSIX.2”) or ANSI X3.159-1989
                        (“ANSI C89”) this should be noted here.  If the command does not adhere
                        to any standard, its history should be noted in the HISTORY section.

     .Sh HISTORY        Any command which does not adhere to any specific standards should be
                        outlined historically in this section.

     .Sh AUTHORS        Credits should be placed here.  Use the ‘.An’ macro for names and the
                        ‘.Aq’ macro for e-mail addresses within optional contact information.
                        Explicitly indicate whether the person authored the initial manual page
                        or the software or whatever the person is being credited for.

     .Sh BUGS           Blatant problems with the topic go here.

     User-specified ‘.Sh’ sections may be added; for example, this section was set with:

                    .Sh "PAGE STRUCTURE DOMAIN"

   Subsection Headers
     Subsection headers have exactly the same syntax as section headers: ‘.Ss’ is parsed but not
     generally callable.  It can be used as an argument in a call to ‘.Ss’ only; it then
     reactivates the default font for ‘.Ss’.

     The default width is 8n.

   Paragraphs and Line Spacing
     .Pp  The ‘.Pp’ paragraph command may be used to specify a line space where necessary.  The
          macro is not necessary after a ‘.Sh’ or ‘.Ss’ macro or before a ‘.Bl’ or ‘.Bd’ macro
          (which both assert a vertical distance unless the -compact flag is given).

          The macro is neither callable nor parsed and takes no arguments; an alternative name is
          ‘.Lp’.

   Keeps
     The only keep that is implemented at this time is for words.  The macros are ‘.Bk’ (begin
     keep) and ‘.Ek’ (end keep).  The only option that ‘.Bk’ accepts currently is -words (this is
     also the default if no option is given) which is useful for preventing line breaks in the
     middle of options.  In the example for the make command line arguments (see What's in a
     Name), the keep prevented nroff from placing up the flag and the argument on separate lines.

     Both macros are neither callable nor parsed.

     More work needs to be done with the keep macros; specifically, a -line option should be
     added.

   Examples and Displays
     There are seven types of displays.

     .D1  (This is D-one.)  Display one line of indented text.  This macro is parsed but not
          callable.

                -ldghfstru

          The above was produced by: .D1 Fl ldghfstru.

     .Dl  (This is D-ell.)  Display one line of indented literal text.  The ‘.Dl’ example macro
          has been used throughout this file.  It allows the indentation (display) of one line of
          text.  Its default font is set to constant width (literal).  ‘.Dl’ is parsed but not
          callable.

                % ls -ldg /usr/local/bin

          The above was produced by: .Dl % ls \-ldg /usr/local/bin.

     .Bd  Begin display.  The ‘.Bd’ display must be ended with the ‘.Ed’ macro.  It has the
          following syntax:

                .Bd {-literal | -filled | -unfilled | -ragged | -centered} [-offset ⟨string⟩]
                     [-file ⟨file name⟩] [-compact]

          -ragged            Fill, but do not adjust the right margin (only left-justify).
          -centered          Center lines between the current left and right margin.  Note that
                             each single line is centered.
          -unfilled          Do not fill; display a block of text as typed, using line breaks as
                             specified by the user.  This can produce overlong lines without
                             warning messages.
          -filled            Display a filled block.  The block of text is formatted (i.e., the
                             text is justified on both the left and right side).
          -literal           Display block with literal font (usually fixed-width).  Useful for
                             source code or simple tabbed or spaced text.
          -filefile name⟩  The file whose name follows the -file flag is read and displayed
                             before any data enclosed with ‘.Bd’ and ‘.Ed’, using the selected
                             display type.  Any troff/-mdoc commands in the file will be
                             processed.
          -offsetstring⟩   If -offset is specified with one of the following strings, the
                             string is interpreted to indicate the level of indentation for the
                             forthcoming block of text:

                             left        Align block on the current left margin; this is the
                                         default mode of ‘.Bd’.
                             center      Supposedly center the block.  At this time
                                         unfortunately, the block merely gets left aligned about
                                         an imaginary center margin.
                             indent      Indent by one default indent value or tab.  The default
                                         indent value is also used for the ‘.D1’ and ‘.Dl’
                                         macros, so one is guaranteed the two types of displays
                                         will line up.  The indentation value is normally set
                                         to 6n or about two thirds of an inch (six constant width
                                         characters).
                             indent-two  Indent two times the default indent value.
                             right       This left aligns the block about two inches from the
                                         right side of the page.  This macro needs work and
                                         perhaps may never do the right thing within troff.

                             If ⟨string⟩ is a valid numeric expression instead (with a scale
                             indicator other thanu’), use that value for indentation.  The most
                             useful scale indicators are ‘m’ and ‘n’, specifying the so-called Em
                             and En square.  This is approximately the width of the letters ‘m’
                             and ‘n’ respectively of the current font (for nroff output, both
                             scale indicators give the same values).  If ⟨string⟩ isn't a numeric
                             expression, it is tested whether it is an -mdoc macro name, and the
                             default offset value associated with this macro is used.  Finally,
                             if all tests fail, the width of ⟨string⟩ (typeset with a fixed-width
                             font) is taken as the offset.
          -compact           Suppress insertion of vertical space before begin of display.

     .Ed  End display (takes no arguments).

   Lists and Columns
     There are several types of lists which may be initiated with the ‘.Bl’ begin-list macro.
     Items within the list are specified with the ‘.It’ item macro, and each list must end with
     the ‘.El’ macro.  Lists may be nested within themselves and within displays.  The use of
     columns inside of lists or lists inside of columns is unproven.

     In addition, several list attributes may be specified such as the width of a tag, the list
     offset, and compactness (blank lines between items allowed or disallowed).  Most of this
     document has been formatted with a tag style list (-tag).

     It has the following syntax forms:

           .Bl {-hang | -ohang | -tag | -diag | -inset} [-width ⟨string⟩] [-offset ⟨string⟩]
                [-compact]
           .Bl -column [-offset ⟨string⟩] ⟨string1⟩ ⟨string2⟩ ...
           .Bl {-item | -enum [-nested] | -bullet | -hyphen | -dash} [-offset ⟨string⟩]
                [-compact]

     And now a detailed description of the list types.

     -bullet  A bullet list.

                    .Bl -bullet -offset indent -compact
                    .It
                    Bullet one goes here.
                    .It
                    Bullet two here.
                    .El

              Produces:

                    ·   Bullet one goes here.
                    ·   Bullet two here.

     -dash (or -hyphen)
              A dash list.

                    .Bl -dash -offset indent -compact
                    .It
                    Dash one goes here.
                    .It
                    Dash two here.
                    .El

              Produces:

                    -   Dash one goes here.
                    -   Dash two here.

     -enum    An enumerated list.

                    .Bl -enum -offset indent -compact
                    .It
                    Item one goes here.
                    .It
                    And item two here.
                    .El

              The result:

                    1.   Item one goes here.
                    2.   And item two here.

              If you want to nest enumerated lists, use the -nested flag (starting with the
              second-level list):

                    .Bl -enum -offset indent -compact
                    .It
                    Item one goes here
                    .Bl -enum -nested -compact
                    .It
                    Item two goes here.
                    .It
                    And item three here.
                    .El
                    .It
                    And item four here.
                    .El

              Result:

                    1.   Item one goes here.
                         1.1.   Item two goes here.
                         1.2.   And item three here.
                    2.   And item four here.

     -item    A list of type -item without list markers.

                    .Bl -item -offset indent
                    .It
                    Item one goes here.
                    Item one goes here.
                    Item one goes here.
                    .It
                    Item two here.
                    Item two here.
                    Item two here.
                    .El

              Produces:

                    Item one goes here.  Item one goes here.  Item one goes here.

                    Item two here.  Item two here.  Item two here.

     -tag     A list with tags.  Use -width to specify the tag width.

                    SL    sleep time of the process (seconds blocked)
                    PAGEIN
                          number of disk I/O's resulting from references by the process to pages
                          not loaded in core.
                    UID   numerical user-id of process owner
                    PPID  numerical id of parent of process priority (non-positive when in non-
                          interruptible wait)

              The raw text:

                    .Bl -tag -width "PPID" -compact -offset indent
                    .It SL
                    sleep time of the process (seconds blocked)
                    .It PAGEIN
                    number of disk
                    .Tn I/O Ns 's
                    resulting from references by the process
                    to pages not loaded in core.
                    .It UID
                    numerical user-id of process owner
                    .It PPID
                    numerical id of parent of process priority
                    (non-positive when in non-interruptible wait)
                    .El

     -diag    Diag lists create section four diagnostic lists and are similar to inset lists
              except callable macros are ignored.  The -width flag is not meaningful in this
              context.

              Example:

                    .Bl -diag
                    .It You can't use Sy here.
                    The message says all.
                    .El

              produces

              You can't use Sy here.  The message says all.

     -hang    A list with hanging tags.

                    Hanged  labels appear similar to tagged lists when the label is smaller than
                            the label width.

                    Longer hanged list labels blend into the paragraph unlike tagged paragraph
                            labels.

              And the unformatted text which created it:

                    .Bl -hang -offset indent
                    .It Em Hanged
                    labels appear similar to tagged lists when the
                    label is smaller than the label width.
                    .It Em Longer hanged list labels
                    blend into the paragraph unlike
                    tagged paragraph labels.
                    .El

     -ohang   Lists with overhanging tags do not use indentation for the items; tags are written
              to a separate line.

                    SL
                    sleep time of the process (seconds blocked)

                    PAGEIN
                    number of disk I/O's resulting from references by the process to pages not
                    loaded in core.

                    UID
                    numerical user-id of process owner

                    PPID
                    numerical id of parent of process priority (non-positive when in non-
                    interruptible wait)

              The raw text:

                    .Bl -ohang -offset indent
                    .It Sy SL
                    sleep time of the process (seconds blocked)
                    .It Sy PAGEIN
                    number of disk
                    .Tn I/O Ns 's
                    resulting from references by the process
                    to pages not loaded in core.
                    .It Sy UID
                    numerical user-id of process owner
                    .It Sy PPID
                    numerical id of parent of process priority
                    (non-positive when in non-interruptible wait)
                    .El

     -inset   Here is an example of inset labels:

                    Tag The tagged list (also called a tagged paragraph) is the most common type
                    of list used in the Berkeley manuals.  Use a -width attribute as described
                    below.

                    Diag Diag lists create section four diagnostic lists and are similar to inset
                    lists except callable macros are ignored.

                    Hang Hanged labels are a matter of taste.

                    Ohang Overhanging labels are nice when space is constrained.

                    Inset Inset labels are useful for controlling blocks of paragraphs and are
                    valuable for converting -mdoc manuals to other formats.

              Here is the source text which produced the above example:

                    .Bl -inset -offset indent
                    .It Em Tag
                    The tagged list (also called a tagged paragraph)
                    is the most common type of list used in the
                    Berkeley manuals.
                    .It Em Diag
                    Diag lists create section four diagnostic lists
                    and are similar to inset lists except callable
                    macros are ignored.
                    .It Em Hang
                    Hanged labels are a matter of taste.
                    .It Em Ohang
                    Overhanging labels are nice when space is constrained.
                    .It Em Inset
                    Inset labels are useful for controlling blocks of
                    paragraphs and are valuable for converting
                    .Nm -mdoc
                    manuals to other formats.
                    .El

     -column  This list type generates multiple columns.  The number of columns and the width of
              each column is determined by the arguments to the -column list, ⟨string1⟩,
              ⟨string2⟩, etc.  If ⟨stringN⟩ starts with a ‘.’ (dot) immediately followed by a
              valid -mdoc macro name, interpret ⟨stringN⟩ and use the width of the result.
              Otherwise, the width of ⟨stringN⟩ (typeset with a fixed-width font) is taken as the
              Nth column width.

              Each ‘.It’ argument is parsed to make a row, each column within the row is a
              separate argument separated by a tab or the ‘.Ta’ macro.

              The table:

                    String    Nroff    Troff
                    <=        <=       ≤
                    >=        >=       ≥

              was produced by:

              .Bl -column -offset indent ".Sy String" ".Sy Nroff" ".Sy Troff"
              .It Sy String Ta Sy Nroff Ta Sy Troff
              .It Li <= Ta <= Ta \*(<=
              .It Li >= Ta >= Ta \*(>=
              .El

              Don't abuse this list type!  For more complicated cases it might be far better and
              easier to use tbl(1), the table preprocessor.

     Other keywords:

     -widthstring⟩   If ⟨string⟩ starts with a ‘.’ (dot) immediately followed by a valid -mdoc
                       macro name, interpret ⟨string⟩ and use the width of the result.  Almost
                       all lists in this document use this option.

                       Example:

                             .Bl -tag -width ".Fl test Ao Ar string Ac"
                             .It Fl test Ao Ar string Ac
                             This is a longer sentence to show how the
                             .Fl width
                             flag works in combination with a tag list.
                             .El

                       gives:

                       -teststring⟩  This is a longer sentence to show how the -width flag
                                       works in combination with a tag list.

                       (Note that the current state of -mdoc is saved before ⟨string⟩ is
                       interpreted; afterwards, all variables are restored again.  However, boxes
                       (used for enclosures) can't be saved in GNU troff(1); as a consequence,
                       arguments must always be balanced to avoid nasty errors.  For example, do
                       not write ‘.Ao Ar string’ but ‘.Ao Ar string Xc’ instead if you really
                       need only an opening angle bracket.)

                       Otherwise, if ⟨string⟩ is a valid numeric expression (with a scale
                       indicator other thanu’), use that value for indentation.  The most
                       useful scale indicators are ‘m’ and ‘n’, specifying the so-called Em and
                       En square.  This is approximately the width of the letters ‘m’ and ‘n’
                       respectively of the current font (for nroff output, both scale indicators
                       give the same values).  If ⟨string⟩ isn't a numeric expression, it is
                       tested whether it is an -mdoc macro name, and the default width value
                       associated with this macro is used.  Finally, if all tests fail, the width
                       of ⟨string⟩ (typeset with a fixed-width font) is taken as the width.

                       If a width is not specified for the tag list type, every time ‘.It’ is
                       invoked, an attempt is made to determine an appropriate width.  If the
                       first argument to ‘.It’ is a callable macro, the default width for that
                       macro will be used; otherwise, the default width of ‘.No’ is used.

     -offsetstring⟩  If ⟨string⟩ is indent, a default indent value (normally set to 6n, similar
                       to the value used in ‘.Dl’ or ‘.Bd’) is used.  If ⟨string⟩ is a valid
                       numeric expression instead (with a scale indicator other thanu’), use
                       that value for indentation.  The most useful scale indicators are ‘m’ and
                       ‘n’, specifying the so-called Em and En square.  This is approximately the
                       width of the letters ‘m’ and ‘n’ respectively of the current font (for
                       nroff output, both scale indicators give the same values).  If ⟨string⟩
                       isn't a numeric expression, it is tested whether it is an -mdoc macro
                       name, and the default offset value associated with this macro is used.
                       Finally, if all tests fail, the width of ⟨string⟩ (typeset with a fixed-
                       width font) is taken as the offset.

     -compact          Suppress insertion of vertical space before the list and between list
                       items.

MISCELLANEOUS MACROS

     Here a list of the remaining macros which do not fit well into one of the above sections.
     We couldn't find real examples for the following macros: ‘.Me’ and ‘.Ot’.  They are
     documented here for completeness - if you know how to use them properly please send a mail
     to bug-groff@gnu.org (including an example).

     .Bt  prints

                is currently in beta test.

          It is neither callable nor parsed and takes no arguments.

     .Fr

                Usage: .Fr ⟨function return value⟩ ...

          Don't use this macro.  It allows a break right before the return value (usually a
          single digit) which is bad typographical behaviour.  Use ‘\~’ to tie the return value
          to the previous word.

     .Hf  Use this macro to include a (header) file literally.  It first prints ‘File:’ followed
          by the file name, then the contents of ⟨file⟩.

                Usage: .Hf ⟨file⟩

          It is neither callable nor parsed.

     .Lk  To be written.

     .Me  Exact usage unknown.  The documentation in the -mdoc source file describes it as a
          macro for “menu entries”.

          Its default width is 6n.

     .Mt  To be written.

     .Ot  Exact usage unknown.  The documentation in the -mdoc source file describes it as “old
          function type (fortran)”.

     .Sm  Activate (toggle) space mode.

                Usage: .Sm [on | off] ...

          If space mode is off, no spaces between macro arguments are inserted.  If called
          without a parameter (or if the next parameter is neither ‘on’ nor ‘off’, ‘.Sm’ toggles
          space mode.

     .Ud  prints

                currently under development.

          It is neither callable nor parsed and takes no arguments.

PREDEFINED STRINGS

     The following strings are predefined:

     String   Nroff      Troff   Meaning
     <=       <=         ≤       less equal
     >=       >=         ≥       greater equal
     Rq       ''         ”       right double quote
     Lq       ``         “       left double quote
     ua       ^          ↑       upwards arrow
     aa       ´          ´       acute accent
     ga       `          `       grave accent
     q        "          "       straight double quote
     Pi       pi         π       greek pi
     Ne       !=         ≠       not equal
     Le       <=         ≤       less equal
     Ge       >=         ≥       greater equal
     Lt       <          <       less than
     Gt       >          >       greater than
     Pm       +-         ±       plus minus
     If       infinity   ∞       infinity
     Am       &          &       ampersand
     Na       NaN        NaN     not a number
     Ba       |          |       vertical bar

     The names of the columns Nroff and Troff are a bit misleading; Nroff shows the ASCII
     representation, while Troff gives the best glyph form available.  For example, a Unicode
     enabled TTY-device will have proper glyph representations for all strings, whereas the
     enhancement for a Latin1 TTY-device is only the plus-minus sign.

     String names which consist of two characters can be written as ‘\*(xx’; string names which
     consist of one character can be written as ‘\*x’.  A generic syntax for a string name of any
     length is ‘\*[xxx]’ (this is a GNU troff(1) extension).

DIAGNOSTICS

     The debugging macro ‘.Db’ available in previous versions of -mdoc has been removed since GNU
     troff(1) provides better facilities to check parameters; additionally, many error and
     warning messages have been added to this macro package, making it both more robust and
     verbose.

     The only remaining debugging macro is ‘.Rd’ which yields a register dump of all global
     registers and strings.  A normal user will never need it.

FORMATTING WITH GROFF, TROFF, AND NROFF

     By default, the package inhibits page breaks, headers, and footers if displayed with a TTY
     device like ‘latin1’ or ‘unicode’, to make the manual more efficient for viewing on-line.
     This behaviour can be changed (e.g. to create a hardcopy of the TTY output) by setting the
     register ‘cR’ to zero while calling groff(1), resulting in multiple pages instead of a
     single, very long page:

           groff -Tlatin1 -rcR=0 -mdoc foo.man > foo.txt

     For double-sided printing, set register ‘D’ to 1:

           groff -Tps -rD1 -mdoc foo.man > foo.ps

     To change the document font size to 11pt or 12pt, set register ‘S’ accordingly:

           groff -Tdvi -rS11 -mdoc foo.man > foo.dvi

     Register ‘S’ is ignored for TTY devices.

     The line and title length can be changed by setting the registers ‘LL’ and ‘LT’,
     respectively:

           groff -Tutf8 -rLL=100n -rLT=100n -mdoc foo.man | less

     If not set, both registers default to 78n for TTY devices and 6.5i otherwise.

FILES

     doc.tmac          The main manual macro package.
     mdoc.tmac         A wrapper file to call doc.tmac.
     mdoc/doc-common   Common strings, definitions, stuff related typographic output.
     mdoc/doc-nroff    Definitions used for a TTY output device.
     mdoc/doc-ditroff  Definitions used for all other devices.
     mdoc.local        Local additions and customizations.
     andoc.tmac        Use this file if you don't know whether the -mdoc or the -man package
                       should be used.  Multiple man pages (in either format) can be handled.

SEE ALSO

     groff(1), man(1), troff(1), groff_man(7)

BUGS

     Section 3f has not been added to the header routines.

     ‘.Nm’ font should be changed in NAME section.

     ‘.Fn’ needs to have a check to prevent splitting up if the line length is too short.
     Occasionally it separates the last parenthesis, and sometimes looks ridiculous if a line is
     in fill mode.

     The list and display macros do not do any keeps and certainly should be able to.