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GROFF_MDOC(7)        BSD Miscellaneous Information Manual        GROFF_MDOC(7)

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, sec-tion section
     tion 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 sub-set subset
     set 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
                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 fol-lowed followed
     lowed by the two-character (or three-character) name for the macro.  There can be space or tab charac-ters characters
     ters 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 zerowidth
     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 gen-eral general
     eral 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 charac-ters, characters,
     ters, say, to specify arguments to commands which expect particular arrangement of items in the argu-ment argument
     ment 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.  Simi-larly, Similarly,
     larly, 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; charac-ters characters
     ters 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 pro-tect protect
     tect 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
           .Os [OPERATING_SYSTEM] [version/release]
           .Dt DOCUMENT_TITLE [section number] [architecture/volume]
           .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', `.Os', and `.Dt'; the document date, the oper-ating operating
     ating 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 pro-duce produce
     duce `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 some-one someone
     one 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 limita-tions. limitations.
             tions.  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 previ-ous previous
             ous 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:

                   alpha, acorn26, acorn32, algor, amd64, amiga, arc, arm26, arm32, atari, bebox, cats,
                   cesfic, cobalt, dreamcast, evbarm, evbmips, evbppc, evbsh3, hp300, hp700, hpcmips, i386,
                   luna68k, m68k, mac68k, macppc, mips, mmeye, mvme68k, mvmeppc, netwinder, news68k,
                   newsmips, next68k, ofppc, pc532, pmax, pmppc, powerpc, prep, sandpoint, sgimips, sh3,
                   shark, sparc, sparc64, sun3, tahoe, vax, x68k, x86_64

             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 pre-defined predefined
             defined 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,
                            2.0, 2.0.1, 2.0.2, 2.1

                   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, 5.0, 5.1, 5.2,
                            5.2.1, 5.3

             For ATT, an unknown second parameter will be replaced with the string UNIX; for the other pre-defined predefined
             defined 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 argu-ments, arguments,
             ments, 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 com-mands, commands,
     mands, 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 prop-erly properly
     erly 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 mem-ber member
     ber 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 .Fl.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 paren-thesis parenthesis
     thesis at that point).

     For functions with many parameters (which is rare), the macros `.Fo' (function open) and `.Fc' (func-tion (function
     tion 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:

           libarm       ARM Architecture Library (libarm, -larm)
           libarm32     ARM32 Architecture Library (libarm32, -larm32)
           libc         Standard C Library (libc, -lc)
           libcdk       Curses Development Kit Library (libcdk, -lcdk)
           libcompat    Compatibility Library (libcompat, -lcompat)
           libcrypt     Crypt Library (libcrypt, -lcrypt)
           libcurses    Curses Library (libcurses, -lcurses)
           libedit      Command Line Editor Library (libedit, -ledit)
           libevent     Event Notification Library (libevent, -levent)
           libform      Curses Form Library (libform, -lform)
           libi386      i386 Architecture Library (libi386, -li386)
           libintl      Internationalized Message Handling Library (libintl, -lintl)
           libipsec     IPsec Policy Control Library (libipsec, -lipsec)
           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)
           libmenu      Curses Menu Library (libmenu, -lmenu)
           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)
           libpthread   POSIX Threads Library (libpthread, -lpthread)
           libresolv    DNS Resolver Library (libresolv, -lresolv)
           librt        POSIX Real-time Library (librt, -lrt)
           libtermcap   Termcap Access Library (libtermcap, -ltermcap)
           libusbhid    USB Human Interface Devices Library (libusbhid, -lusbhid)
           libutil      System Utilities Library (libutil, -lutil)
           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.  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'')

     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'')

     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 System Interface 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.

   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 1_24.
                    .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)    XXstringXX
         .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 respec-tively, respectively,
               tively, 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 tradi-tional traditional
     tional 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 conve-nient convenient
     nient 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.
           .%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 head-ers headers
     ers 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 lay-out layout
                        out 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 sub-ject subject
                        ject of the man page.  The second is the name description macro, `.Nd', which sepa-rates separates
                        rates the subject name from the third item, which is the description.  The descrip-tion description
                        tion 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 sec-tion section
                        tion 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 accom-modated. accommodated.
                        modated.

                        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 his-torically historically
                        torically 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 ver-tical vertical
          tical 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 exam-ple example
     ple 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 syn-tax: syntax:
          tax:

                .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 jus-tified justified
                             tified 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.
          -file <file 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.
          -offset <string>   If -offset is specified with one of the following strings, the string is inter-preted interpreted
                             preted 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 guar-anteed guaranteed
                                         anteed 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
                             than `u'), use that value for indentation.  The most useful scale indicators
                             are `m' and `n', specifying the so-called Em and En square.  This is approxi-mately approximately
                             mately 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 format-ted formatted
     ted 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 sepa-rate separate
              rate 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 fixedwidth
              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

     Other keywords:

     -width <string>   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 docu-ment document
                       ment 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:

                       -test <string>  This is a longer sentence to show how the -width flag works in combi-nation combination
                                       nation with a tag list.

                       (Note that the current state of -mdoc is saved before <string> is interpreted; after-wards, afterwards,
                       wards, 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
                       than `u'), 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.

     -offset <string>  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 than `u'), 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 complete-ness completeness
     ness - if you know how to use them properly please send a mail to bug-groff@gnu.org (including an exam-ple). example).
     ple).

     .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 parame-ter parameter
          ter (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          pi        greek pi
           Ne        !=          !=        not equal
           Le        <=          <=        less equal
           Ge        >=          >=        greater equal
           Lt        <           <         less than
           Gt        >           >         greater than
           Pm        +-          +-        plus minus
           If        infinity    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 call-ing calling
     ing 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        This file checks whether the -mdoc or the -man package should be used.

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.

BSD                             August 28, 2005                            BSD

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