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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, 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	do-
     main.  The	general	text domain is defined as macros which perform tasks
     such as quoting or	emphasizing pieces of text.  The manual	domain is de-
     fined 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	op-
     tions, 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.	Hope-
     fully, 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 un-
     avoidable 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-charac-
     ter) 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)	char-
     acters as a macro name.  A	single starting	dot followed by	nothing	is ig-
     nored.  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	spe-
     cial 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, al-
     though 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.	 Addi-
     tionally, it makes	-mdoc working faster.  For example, the	function com-
     mand `.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 embed-
     ded space.	 One way of passing a string containing	blank spaces is	to use
     the hard or unpaddable space character `\ ', that is, a blank space pre-
     ceded 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 new-
     line separated pieces as one would	expect.	 This method is	useful for
     strings which are not expected to overlap a line boundary.	 An alterna-
     tive 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 re-
     sult 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 un-
     paddable space and	the `\&' escape	character.  For	example, `string\ \&'.

   Escaping Special Characters
     Special characters	like the newline character `\n'	are handled by replac-
     ing 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 dis-
     plays (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 charac-
     ter between words in an ordinary text line; contrary to other text	for-
     matters, they are not replaced with a single space.

     You can't pass `"'	directly as an argument.  Use `\*[q]' (or `\*q') in-
     stead.

     By	default, troff(1) inserts two space characters after a punctuation
     mark closing a sentence; characters like `)' or `'' are treated transpar-
     ently, 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 sec-
     tion 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 lat-
     ter 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 iden-
     tify 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 argu-
     ments.  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 speci-
     fied 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>'.  Conse-
     quently, a	warning	message	is emitted for most commands if	the first ar-
     gument is a macro itself since it cancels the effect of the calling com-
     mand 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 la-
     bel width (-width)	or offset (-offset) for	the `.Bl' and `.Bd' macros.
     It	is recommended not to use this rather obscure feature to avoid depen-
     dencies 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 vol-
	     ume name is given,	a default volume name is used.

	     Under , the following sections are	defined:

	     1	 FreeBSD
	     2	 FreeBSD
	     3	 FreeBSD
	     4	 FreeBSD
	     5	 FreeBSD
	     6	 FreeBSD
	     7	 FreeBSD
	     8	 FreeBSD
	     9	 FreeBSD

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

	     USD
	     PS1
	     AMD
	     SMM
	     URM
	     PRM
	     KM
	     IND
	     LOCAL
	     CON

	     For compatibility,	`MMI' can be used for `IND', and `LOC' for
	     `LOCAL'.  Values from the previous	table will specify a new vol-
	     ume name.	If the third parameter is a keyword designating	a com-
	     puter architecture, its value is prepended	to the default volume
	     name as specified by the second parameter.	 By default, the fol-
	     lowing 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 nu-
	     meric expression.

		   .Dt FOO 7	   `FOO(7)' `FreeBSD'
		   .Dt FOO 7 bar   `FOO(7)' `FreeBSD'
		   .Dt FOO \&7 bar
				   `FOO(7)' `bar'
		   .Dt FOO 2 i386  `FOO(2)' `FreeBSD/'
		   .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 for-
	     mer 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 `' 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 re-
	     lease nomenclature	for the	system specified.  In the following
	     table, the	possible second	arguments for some predefined operat-
	     ing 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	dis-
	     played 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, sepa-
	     rated 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, ig-
	     noring 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 de-
     scription 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 confu-
     sion, 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 recog-
     nizing and	properly handling punctuation, provided	each punctuation char-
     acter 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 distin-
     guishing 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 quota-
     tion 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 `\&'.	Typi-
     cal 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 be-
     ing 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 de-
     vice 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 decla-
     ration 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	 <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' (func-
     tion 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, respec-
     tively.

   Function Arguments
     The `.Fa' macro is	used to	refer to function arguments (parameters) out-
     side 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.  Cur-
     rently, 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.	 Cur-
     rently, 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 func-
     tion 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 con-
     stants, 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 identi-
     cal 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 brack-
     ets.  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, respec-
     tively.

   Pathnames
     The `.Pa' macro formats path or file names.  If called without arguments,
     the `~' string is output, which represents	the current user's home	direc-
     tory.

	   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 en-
     close 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 irregu-
     larities.	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 ob-
	       solete: `.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 func-
	       tion.

     .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 posi-
     tion 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 ref-
		   erence 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.
	   .%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 parame-
     ter; 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"
	   .%C "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 in-
     tended 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 im-
     plemented 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	vari-
     able.

	   .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	gener-
     ally 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 re-
			quire 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	sec-
			tion is	a brief	paragraph on the command, function or
			file, followed by a lexical list of options and	re-
			spective 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 en-
			vironment variables and	clues to their behavior	and/or
			usage.

     .Sh FILES		Files which are	used or	created	by the man page	sub-
			ject 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 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 func-
			tions (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 sec-
			tion.

     .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 indi-
			cate 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	op-
     tions.  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	argu-
     ment 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	mes-
			     sages.
	  -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.
	  -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 pro-
			     cessed.
	  -offset <string>   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 mar-
					 gin; 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 per-
					 haps 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 in-
			     dicators 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.	Fi-
			     nally, 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 al-
     lowed 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:

		    o	Bullet one goes	here.
		    o	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-pos-
			  itive	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 la-
			    bel	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 ig-
		    nored.

		    Hang Hanged	labels are a matter of taste.

		    Ohang Overhanging labels are nice when space is con-
		    strained.

		    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	col-
	      umns 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:

     -width <string>   If <string> starts with a `.' (dot) immediately fol-
		       lowed 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:

		       -test <string>  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, argu-
		       ments 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.	Fi-
		       nally, if all tests fail, the width of <string> (type-
		       set with	a fixed-width font) is taken as	the width.

		       If a width is not specified for the tag list type, ev-
		       ery time	`.It' is invoked, an attempt is	made to	deter-
		       mine 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 in-
		       stead (with a scale indicator other than	`u'), use that
		       value for indentation.  The most	useful scale indica-
		       tors are	`m' and	`n', specifying	the so-called Em and
		       En square.  This	is approximately the width of the let-
		       ters `m'	and `n'	respectively of	the current font (for
		       nroff output, both scale	indicators give	the same val-
		       ues).  If <string> isn't	a numeric expression, it is
		       tested whether it is an -mdoc macro name, and the de-
		       fault 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 off-
		       set.

     -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 (includ-
     ing 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 de-
	  scribes 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 de-
	  scribes 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 in-
	  serted.  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	 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 pa-
     rameters; 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 man-
     ual 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'	ac-
     cordingly:

	   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	other-
     wise.

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.

BSD			       November	2, 2010				   BSD

NAME | SYNOPSIS | DESCRIPTION | GETTING STARTED | TROFF IDIOSYNCRASIES | A MANUAL PAGE TEMPLATE | CONVENTIONS | TITLE MACROS | INTRODUCTION OF MANUAL AND GENERAL TEXT DOMAINS | MANUAL DOMAIN | GENERAL TEXT DOMAIN | PAGE STRUCTURE DOMAIN | MISCELLANEOUS MACROS | PREDEFINED STRINGS | DIAGNOSTICS | FORMATTING WITH GROFF, TROFF, AND NROFF | FILES | SEE ALSO | BUGS

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