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.\" groff_mdoc.man
.\"
.\"   A complete reference of the mdoc macro package for GNU troff.
.\"
.\" Based on NetBSD's mdoc.samples.7, version 1.21.
.\"
.\"
.\"   Warning: You can't format this file with the old mdoc macros!
.\"
.\"
.\" Copyright (c) 1990, 1993
.\"     The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. [Deleted.  See
.\"     ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change]
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)mdoc.samples.7 8.2 (Berkeley) 12/30/93
.\"
.\" This reference invokes every macro in the package several
.\" times and is guaranteed to give a worst case performance
.\" for an already extremely slow package.
.\"
.
.Dd November 2, 2010
.Dt GROFF_MDOC 7
.Os
.
.
.Sh NAME
.
.Nm groff_mdoc
.Nd reference for groff's mdoc implementation
.
.
.Sh SYNOPSIS
.
.Nm groff Fl m Ns Cm doc Ar
.
.
.Sh DESCRIPTION
.
A complete reference for writing
.Ux
manual pages with the
.Nm \-mdoc
macro package; a
.Em content Ns -based
and
.Em domain Ns -based
formatting package for
.Tn GNU
.Xr troff 1 .
Its predecessor, the
.Xr \-man 7
package, addressed page layout leaving the manipulation of fonts and other
typesetting details to the individual author.
In
.Nm \-mdoc ,
page layout macros make up the
.Em "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
.Em manual
domain and the
.Em general
text domain.
The general text domain is defined as macros which perform tasks such as
quoting or emphasizing pieces of text.
The manual domain is defined as macros that are a subset of the day to day
informal language used to describe commands, routines and related
.Ux
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.
.Pp
Throughout the
.Ux
manual pages, a manual entry is simply referred to as a man page, regardless
of actual length and without sexist intention.
.
.
.Sh "GETTING STARTED"
.
The material presented in the remainder of this document is outlined
as follows:
.
.Bl -enum -width 3n -offset indent
.  It
.  Tn "TROFF IDIOSYNCRASIES"
.
.  Bl -tag -width 2n -compact
.    It "Macro Usage"
.    It "Passing Space Characters in an Argument"
.    It "Trailing Blank Space Characters"
.    It "Escaping Special Characters"
.    It "Other Possible Pitfalls"
.  El
.
.  It
.  Tn "A MANUAL PAGE TEMPLATE"
.
.  It
.  Tn "CONVENTIONS"
.
.  It
.  Tn "TITLE MACROS"
.
.  It
.  Tn "INTRODUCTION OF MANUAL AND GENERAL TEXT DOMAINS"
.
.  Bl -tag -width 2n -compact
.    It "What's in a Name" Ns ...
.    It "General Syntax"
.  El
.
.  It
.  Tn "MANUAL DOMAIN"
.
.  Bl -tag -width 2n -compact
.    It "Addresses"
.    It "Author Name"
.    It "Arguments"
.    It "Configuration Declarations (Section Four Only)"
.    It "Command Modifiers"
.    It "Defined Variables"
.    It "Errno's"
.    It "Environment Variables"
.    It "Flags"
.    It "Function Declarations"
.    It "Function Types"
.    It "Functions (Library Routines)"
.    It "Function Arguments"
.    It "Return Values"
.    It "Exit Status"
.    \" .It "Header File (including source code)"
.    It "Interactive Commands"
.    It "Library Names"
.    It "Literals"
.    It "Names"
.    It "Options"
.    It "Pathnames"
.    It "Standards"
.    It "Variable Types"
.    It "Variables"
.    It "Manual Page Cross References"
.  El
.
.  It
.  Tn "GENERAL TEXT DOMAIN"
.
.  Bl -tag -width 2n -compact
.    It "AT&T Macro"
.    It "BSD Macro"
.    It "NetBSD Macro"
.    It "FreeBSD Macro"
.    It "DragonFly Macro"
.    It "OpenBSD Macro"
.    It "BSD/OS Macro"
.    It "UNIX Macro"
.    It "Emphasis Macro"
.    It "Font Mode"
.    It "Enclosure and Quoting Macros"
.    It "No-Op or Normal Text Macro"
.    It "No-Space Macro"
.    It "Section Cross References"
.    It "Symbolics"
.    It "Mathematical Symbols"
.    It "References and Citations"
.    It "Trade Names (or Acronyms and Type Names)"
.    It "Extended Arguments"
.  El
.
.  It
.  Tn "PAGE STRUCTURE DOMAIN"
.
.  Bl -tag -width 2n -compact
.    It "Section Headers"
.    It "Subsection Headers"
.    It "Paragraphs and Line Spacing"
.    It "Keeps"
.    It "Examples and Displays"
.    It "Lists and Columns"
.  El
.
.  It
.  Tn "MISCELLANEOUS MACROS"
.
.  It
.  Tn "PREDEFINED STRINGS"
.
.  It
.  Tn "DIAGNOSTICS"
.
.  It
.  Tn "FORMATTING WITH GROFF, TROFF, AND NROFF"
.
.  It
.  Tn "FILES"
.
.  It
.  Tn "SEE ALSO"
.
.  It
.  Tn "BUGS"
.El
.
.\" XXX
.if t \
.  ne 7
.
.
.Sh "TROFF IDIOSYNCRASIES"
.
The
.Nm \-mdoc
package attempts to simplify the process of writing a man page.
Theoretically, one should not have to learn the tricky details of
.Tn GNU
.Xr troff 1
to use
.Nm \-mdoc ;
however, there are a few limitations which are unavoidable and best gotten
out of the way.
And, too, be forewarned, this package is
.Em not
fast.
.
.Ss "Macro Usage"
.
As in
.Tn GNU
.Xr troff 1 ,
a macro is called by placing a
.Ql .\&
(dot character) at the beginning of a line followed by the two-character
(or three-character) name for the macro.
There can be space or tab characters between the dot and the macro name.
Arguments may follow the macro separated by spaces (but
.Em no
tabs).
It is the dot character at the beginning of the line which causes
.Tn GNU
.Xr 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
.Ql .\&
(dot character) at the beginning of an input line in some context other than
a macro invocation, precede the
.Ql .\&
(dot) with the
.Ql \e&
escape sequence which translates literally to a zero-width space, and is
never displayed in the output.
.Pp
In general,
.Tn GNU
.Xr 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
.Sx Extended Arguments
below).
Almost all macros handle quoted arguments (see
.Sx Passing Space Characters in an Argument
below).
.Pp
Most of the
.Nm \-mdoc
general text domain and manual domain macros are special in that their
argument lists are
.Em parsed
for callable macro names.
This means an argument on the argument list which matches a general text or
manual domain macro name (and which is defined to be callable) will be
executed or called when it is processed.
In this case the argument, although the name of a macro, is not preceded by
a
.Ql .\&
(dot).
This makes it possible to nest macros; for example the option macro,
.Ql .Op ,
may
.Em call
the flag and argument macros,
.Ql \&Fl
and
.Ql \&Ar ,
to specify an optional flag with an argument:
.
.Bl -tag -width ".Op Fl s Ar bytes" -offset indent
.It Op Fl s Ar bytes
is produced by
.Ql ".Op Fl s Ar bytes"
.El
.
.Pp
To prevent a string from being interpreted as a macro name, precede the
string with the escape sequence
.Ql \e& :
.
.Bl -tag -width ".Op \&Fl s \&Ar bytes" -offset indent
.It Op \&Fl s \&Ar bytes
is produced by
.Ql ".Op \e&Fl s \e&Ar bytes"
.El
.
.Pp
Here the strings
.Ql \&Fl
and
.Ql \&Ar
are not interpreted as macros.
Macros whose argument lists are parsed for callable arguments are referred
to as
.Em parsed
and macros which may be called from an argument list are referred to as
.Em callable
throughout this document.
This is a technical
.Em faux pas
as almost all of the macros in
.Nm \-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.
.
.Pp
In the following, we call an
.Nm \-mdoc
macro which starts a line (with a leading dot) a
.Em command
if this distinction is necessary.
.
.Ss "Passing Space Characters in an Argument"
.
Sometimes it is desirable to give as an argument a string containing one or
more blank space characters, say, to specify arguments to commands which
expect particular arrangement of items in the argument list.
Additionally, it makes
.Nm \-mdoc
working faster.
For example, the function command
.Ql .Fn
expects the first argument to be the name of a function and any remaining
arguments to be function parameters.
As
.Tn 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,
.Fa int foo .
.Pp
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
.Ql \e\  ,
that is, a blank space preceded by the escape character
.Ql \e .
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.
.Xr 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
.Ql \e~ ,
a paddable (i.e.\& stretchable), unbreakable space (this is a
.Tn GNU
.Xr troff 1
extension).
The second method is to enclose the string with double quotes.
.Pp
For example:
.
.Bl -tag -width ".Fn fetch char\ *str" -offset indent
.It Fn fetch char\ *str
is created by
.Ql ".Fn fetch char\e *str"
.It Fn fetch "char *str"
can also be created by
.Ql ".Fn fetch \*[q]char *str\*[q]"
.El
.
.Pp
If the
.Ql \e
before the space in the first example
or double quotes in the second example
were omitted,
.Ql .Fn
would see three arguments, and the result would be:
.Pp
.Dl Fn fetch char *str
.Pp
.\" For an example of what happens when the parameter list overlaps a newline
.\" boundary, see the
.\" .Sx BUGS
.\" section.
.
.Ss "Trailing Blank Space Characters"
.
.Xr 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
.Ao blank-space Ac Ns Ao end-of-line Ac
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
.Ql \e&
escape character.
For example,
.Ql string\e\ \e& .
.
.Ss "Escaping Special Characters"
.
Special characters like the newline character
.Ql \en
are handled by replacing the
.Ql \e
with
.Ql \ee
(e.g.\&
.Ql \een )
to preserve the backslash.
.
.Ss "Other Possible Pitfalls"
.
A warning is emitted when an empty input line is found outside of displays
(see below).
Use
.Ql .sp
instead.
(Well, it is even better to use
.Nm \-mdoc
macros to avoid the usage of low-level commands.)
.Pp
Leading spaces will cause a break and are output directly.
Avoid this behaviour if possible.
Similarly, do not use more than one space character between words in an
ordinary text line; contrary to other text formatters, they are
.Em not
replaced with a single space.
.Pp
You can't pass
.Ql \*[q]
directly as an argument.
Use
.Ql \e*[q]
(or
.Ql \e*q )
instead.
.Pp
By default,
.Xr troff 1
inserts two space characters after a punctuation mark closing a sentence;
characters like
.Ql \&)
or
.Ql \&'
are treated transparently, not influencing the sentence-ending behaviour.
To change this, insert
.Ql \e&
before or after the dot:
.
.Bd -literal -offset indent
The
\&.Ql .
character.
\&.Pp
The
\&.Ql \e&.
character.
\&.Pp
\&.No test .
test
\&.Pp
\&.No test.
test
.Ed
.Pp
.
gives
.
.Bd -filled -offset indent
The
.Ql .
character
.Pp
The
.Ql \&.
character.
.Pp
.No test .
test
.Pp
.No test.
test
.Ed
.Pp
.
As can be seen in the first and third line,
.Nm \-mdoc
handles punctuation characters specially in macro arguments.
This will be explained in section
.Sx General Syntax
below.
In the same way, you have to protect trailing full stops of abbreviations
with a trailing zero-width space:
.Ql e.g.\e& .
.Pp
A comment in the source file of a man page can be either started with
.Ql .\e"
on a single line,
.Ql \e"
after some input, or
.Ql \e#
anywhere (the latter is a
.Tn GNU
.Xr troff 1
extension); the rest of such a line is ignored.
.
.
.Sh "A MANUAL PAGE TEMPLATE"
.
The body of a man page is easily constructed from a basic template:
.
.Bd -literal -offset indent
\&.\e" 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
\&.\e" This next command is for sections 2 and 3 only.
\&.\e" .Sh LIBRARY
\&.Sh SYNOPSIS
\&.Sh DESCRIPTION
\&.\e" The following commands should be uncommented and
\&.\e" used where appropriate.
\&.\e" .Sh IMPLEMENTATION NOTES
\&.\e" This next command is for sections 2, 3 and 9 function
\&.\e" return values only.
\&.\e" .Sh RETURN VALUES
\&.\e" This next command is for sections 1, 6, 7 and 8 only.
\&.\e" .Sh ENVIRONMENT
\&.\e" .Sh FILES
\&.\e" .Sh EXAMPLES
\&.\e" This next command is for sections 1, 6, 7, 8 and 9 only
\&.\e"     (command return values (to shell) and
\&.\e"     fprintf/stderr type diagnostics).
\&.\e" .Sh DIAGNOSTICS
\&.\e" .Sh COMPATIBILITY
\&.\e" This next command is for sections 2, 3 and 9 error
\&.\e"     and signal handling only.
\&.\e" .Sh ERRORS
\&.\e" .Sh SEE ALSO
\&.\e" .Sh STANDARDS
\&.\e" .Sh HISTORY
\&.\e" .Sh AUTHORS
\&.\e" .Sh BUGS
.Ed
.Pp
.
The first items in the template are the commands
.Ql .Dd ,
.Ql .Dt ,
and
.Ql .Os ;
the document date, the operating system the man page or subject source is
developed or modified for, and the man page title (in
.Em upper case )
along with the section of the manual the page belongs in.
These commands identify the page and are discussed below in
.Sx TITLE MACROS .
.Pp
The remaining items in the template are section headers
.Pf ( Li .Sh ) ;
of which
.Sx NAME ,
.Sx SYNOPSIS ,
and
.Sx DESCRIPTION
are mandatory.
The headers are discussed in
.Sx "PAGE STRUCTURE DOMAIN" ,
after presentation of
.Sx "MANUAL DOMAIN" .
Several content macros are used to demonstrate page layout macros; reading
about content macros before page layout macros is recommended.
.
.
.Sh CONVENTIONS
.
In the description of all macros below, optional arguments are put into
brackets.
An ellipsis
.Pf ( Sq ... )
represents zero or more additional arguments.
Alternative values for a parameter are separated with
.Ql | .
If there are alternative values for a mandatory parameter, braces are used
(together with
.Ql | )
to enclose the value set.
Meta-variables are specified within angles.
.Pp
Example:
.
.Bl -tag -width 6n -offset indent
.It Li .Xx Xo
.Aq foo 
.Brq bar1 | bar2
.Op \-test1 Op \-test2 | \-test3
.No ...
.Xc
.El
.
.Pp
Except stated explicitly, all macros are parsed and callable.
.Pp
Note that a macro takes effect up to the next nested macro.
For example,
.Ql ".Ic foo Aq bar"
doesn't produce
.Sq Ic "foo <bar>"
but
.Sq Ic foo Aq 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;
.Sq Ic "foo <bar>"
has been produced by
.Ql ".Ic \*[q]foo <bar>\*[q]" .
.Pp
Most macros have a default width value which can be used to specify a label
width
.Pf ( Fl width )
or offset
.Pf ( Fl offset )
for the
.Ql .Bl
and
.Ql .Bd
macros.
It is recommended not to use this rather obscure feature to avoid
dependencies on local modifications of the
.Nm \-mdoc
package.
.
.
.Sh "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.
.
.Bl -tag -width 6n
.It Li .Dt Xo
.Op Aq document title
.Op Aq section number
.Op Aq volume
.Xc
The document title is the subject of the man page and must be in
.Tn CAPITALS
due to troff limitations.
If omitted,
.Sq Tn UNTITLED
is used.
The section number may be a number in the range
.No 1,\~ Ns ... Ns ,\~9
or
.Ql unass ,
.Ql draft ,
or
.Ql paper .
If it is specified, and no volume name is given, a default volume name is
used.
.
.Pp
Under
.Tn \*[operating-system] ,
the following sections are defined:
.Pp
.Bl -column LOCAL -offset indent -compact
.It Li 1   Ta "\*[volume-operating-system] \*[volume-ds-1]"
.It Li 2   Ta "\*[volume-operating-system] \*[volume-ds-2]"
.It Li 3   Ta "\*[volume-operating-system] \*[volume-ds-3]"
.It Li 4   Ta "\*[volume-operating-system] \*[volume-ds-4]"
.It Li 5   Ta "\*[volume-operating-system] \*[volume-ds-5]"
.It Li 6   Ta "\*[volume-operating-system] \*[volume-ds-6]"
.It Li 7   Ta "\*[volume-operating-system] \*[volume-ds-7]"
.It Li 8   Ta "\*[volume-operating-system] \*[volume-ds-8]"
.It Li 9   Ta "\*[volume-operating-system] \*[volume-ds-9]"
.El
.Pp
.
A volume name may be arbitrary or one of the following:
.
.Pp
.Bl -column LOCAL -offset indent -compact
.It Li USD   Ta "\*[volume-ds-USD]"
.It Li PS1   Ta "\*[volume-ds-PS1]"
.It Li AMD   Ta "\*[volume-ds-AMD]"
.It Li SMM   Ta "\*[volume-ds-SMM]"
.It Li URM   Ta "\*[volume-ds-URM]"
.It Li PRM   Ta "\*[volume-ds-PRM]"
.It Li KM    Ta "\*[volume-ds-KM]"
.It Li IND   Ta "\*[volume-ds-IND]"
.It Li LOCAL Ta "\*[volume-ds-LOCAL]"
.It Li CON   Ta "\*[volume-ds-CON]"
.El
.Pp
.
For compatibility,
.Ql MMI
can be used for
.Ql IND ,
and
.Ql LOC
for
.Ql LOCAL .
Values from the previous table will specify a new volume name.
If the third parameter is a keyword designating a computer architecture,
its value is prepended to the default volume name as specified by the
second parameter.
By default, the following architecture keywords are defined:
.
\# we use `No' to avoid hyphenation
.Bd -ragged -offset indent
.No alpha , acorn26 , acorn32 , algor , amd64 , amiga , arc , arm26 ,
.No arm32 , atari , bebox , cats , cesfic , cobalt , dreamcast , evbarm ,
.No evbmips , evbppc , evbsh3 , hp300 , hp700 , hpcmips , i386 , luna68k ,
.No m68k , mac68k , macppc , mips , mmeye , mvme68k , mvmeppc , netwinder ,
.No news68k , newsmips , next68k , ofppc , pc532 , pmax , pmppc , powerpc ,
.No prep , sandpoint , sgimips , sh3 , shark , sparc , sparc64 , sun3 ,
.No tahoe , vax , x68k , x86_64
.Ed
.Pp
.
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.
.Pp
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
.Ql \e&
prevents the digit\~7 from being a valid numeric expression.
.
.Bd -ragged
.Bl -tag -width ".Li .Dt\ FOO\ 2\ i386" -compact -offset indent
.It Li ".Dt FOO 7"
.Ql FOO(7)
.Ql \*[volume-operating-system] \*[volume-ds-7]
.It Li ".Dt FOO 7 bar"
.Ql FOO(7)
.Ql \*[volume-operating-system] \*[volume-ds-7]
.It Li ".Dt FOO \e&7 bar"
.Ql FOO(7)
.Ql bar
.It Li ".Dt FOO 2 i386"
.Ql FOO(2)
.Ql \*[volume-operating-system]/\*[volume-as-i386] \*[volume-ds-2]
.It Li ".Dt FOO \*[q]\*[q] bar"
.Ql FOO
.Ql bar
.El
.Ed
.Pp
.
Local, OS-specific additions might be found in the file
.Pa mdoc.local ;
look for strings named
.Ql volume\-ds\-XXX
(for the former type) and
.Ql volume\-as\-XXX
(for the latter type);
.Ql XXX
then denotes the keyword to be used with the
.Ql .Dt
macro.
.Pp
This macro is neither callable nor parsed.
.
.It Li .Os Xo
.Op Aq operating system
.Op Aq release
.Xc
If the first parameter is empty,
the default
.Sq Tn "\*[operating-system]"
is used.
This may be overridden in the local configuration file,
.Pa mdoc.local .
In general, the name of the operating system should be the common acronym,
e.g.\&
.Tn BSD
or
.Tn ATT .
The release should be the standard release nomenclature for the system
specified.
In the following table, the possible second arguments for some predefined
operating systems are listed.
Similar to
.Ql .Dt ,
local additions might be defined in
.Pa mdoc.local ;
look for strings named
.Ql operating\-system\-XXX\-YYY ,
where
.Ql XXX
is the acronym for the operating system and
.Ql YYY
the release ID.
.
.Bd -ragged -compact
.Bl -tag -width ".No DragonFly" -offset indent
.It ATT
7th, 7, III, 3, V, V.2, V.3, V.4
.It BSD
3, 4, 4.1, 4.2, 4.3, 4.3t, 4.3T, 4.3r, 4.3R, 4.4
.It 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, 3.1, 4.0,
4.0.1, 5.0, 5.0.1, 5.0.2
.It 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
.It 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
.It 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
.It 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
.El
.Ed
.Pp
.
For
.Tn ATT ,
an unknown second parameter will be replaced with the string
.Tn UNIX ;
for the other predefined acronyms it will be ignored and a warning message
emitted.
Unrecognized arguments are displayed as given in the page footer.
For instance, a typical footer might be:
.Pp
.Dl .Os BSD 4.3
.Pp
giving
.Ql 4.3\~Berkeley Distribution ,
or for a locally produced set
.Pp
.Dl .Os CS Department
.Pp
which will produce
.Ql CS\~Department .
.Pp
If the
.Ql .Os
macro is not present, the bottom left corner of the manual page will be
ugly.
.Pp
This macro is neither callable nor parsed.
.
.It Li .Dd Oo
.Aq month
.Aq day ,
.Aq year
.Oc
If
.Ql Dd
has no arguments,
.Ql Epoch
is used for the date string.
If it has exactly three arguments, they are concatenated, separated with
unbreakable space:
.Pp
.Dl .Dd January 25, 2001
.Pp
The month's name shall not be abbreviated.
.Pp
With any other number of arguments, the current date is used, ignoring
the parameters.
.Pp
This macro is neither callable nor parsed.
.El
.
.
.Sh "INTRODUCTION OF MANUAL AND GENERAL TEXT DOMAINS"
.
.Ss "What's in a Name" Ns ...
.
The manual domain macro names are derived from the day to day informal
language used to describe commands, subroutines and related files.
Slightly different variations of this language are used to describe the
three different aspects of writing a man page.
First, there is the description of
.Nm \-mdoc
macro command usage.
Second is the description of a
.Ux
command
.Em with
.Nm \-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.
.Pp
In the first case,
.Xr troff 1
macros are themselves a type of command; the general syntax for a troff
command is:
.
.Bd -filled -offset indent
.Li ".Xx argument1 argument2" ...
.Ed
.Pp
.
.Ql .Xx
is a macro command, and anything following it are arguments to
be processed.
In the second case, the description of a
.Ux
command using the content macros is a bit more involved; a typical
.Sx SYNOPSIS
command line might be displayed as:
.
.Bd -filled -offset indent
.Nm filter
.Op Fl flag
.Ao Ar infile Ac Ao Ar outfile Ac
.Ed
.Pp
.
Here,
.Nm filter
is the command name and the
bracketed string
.Fl flag
is a
.Em flag
argument designated as optional by the option brackets.
In
.Nm \-mdoc
terms,
.Ao Ar infile Ac
and
.Ao Ar outfile Ac
are called
.Em 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
.Nm \-mdoc
commands; in most man pages, meta variables are not specifically written
with angle brackets.
The macros which formatted the above example:
.
.Bd -literal -offset indent
\&.Nm filter
\&.Op Fl flag
\&.Ao Ar infile Ac Ao Ar outfile Ac
.Ed
.Pp
.
In the third case, discussion of commands and command syntax includes both
examples above, but may add more detail.
The arguments
.Ao Ar infile Ac
and
.Ao Ar outfile Ac
from the example above might be referred to as
.Em operands
or
.Em file arguments .
Some command line argument lists are quite long:
.
.Bd -ragged
.Bl -tag -width ".Nm make" -offset indent -compact
.It 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
.El
.Ed
.Pp
.
Here one might talk about the command
.Nm make
and qualify the argument,
.Ar makefile ,
as an argument to the flag,
.Fl f ,
or discuss the optional file operand
.Ar target .
In the verbal context, such detail can prevent confusion, however the
.Nm \-mdoc
package does not have a macro for an argument
.Em to
a flag.
Instead the
.Ql \&Ar
argument macro is used for an operand or file argument like
.Ar target
as well as an argument to a flag like
.Ar variable .
The make command line was produced from:
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
.
The
.Ql .Bk
and
.Ql .Ek
macros are explained in
.Sx Keeps .
.
.Ss "General Syntax"
.
The manual domain and general text domain macros share a similar syntax with
a few minor deviations; most notably,
.Ql .Ar ,
.Ql .Fl ,
.Ql .Nm ,
and
.Ql .Pa
differ only when called without arguments; and
.Ql .Fn
and
.Ql .Xr
impose an order on their argument lists.
All content macros are capable of recognizing and properly handling
punctuation, provided each punctuation character is separated by a leading
space.
If a command is given:
.Pp
.Dl \&.Ar sptr, ptr),
.Pp
The result is:
.Pp
.Dl Ar sptr, ptr),
.Pp
The punctuation is not recognized and all is output in the
font used by
.Ql .Ar .
If the punctuation is separated by a leading white space:
.Pp
.Dl \&.Ar "sptr , ptr ) ,"
.Pp
The result is:
.Pp
.Dl Ar sptr , ptr ) ,
.Pp
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
.Ql \e& .
.Pp
The following punctuation characters are recognized by
.Nm \-mdoc :
.
.Bl -column -offset indent-two XXXXXX XXXXXX XXXXXX XXXXXX
.It Li .\& Ta Li ,\& Ta Li :\& Ta Li ;\& Ta Li (\&
.It Li )\& Ta Li [\& Ta Li ]\& Ta Li ?\& Ta Li !\&
.El
.Pp
.
.Xr Troff
is limited as a macro language, and has difficulty when presented with a
string containing a member of the mathematical, logical or quotation set:
.
.Bd -literal -offset indent-two
{+,\-,/,*,%,<,>,<=,>=,=,==,&,`,',"}
.Ed
.Pp
.
The problem is that
.Xr 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
.Ql \e& .
Typical syntax is shown in the first content macro displayed below,
.Ql .Ad .
.
.
.Sh "MANUAL DOMAIN"
.
.Ss Addresses
.
The address macro identifies an address construct.
.Pp
.Dl Usage: .Ad Ao address Ac ...
.Pp
.Bl -tag -width ".Li .Ad\ f1\ ,\ f2\ ,\ f3\ :" -compact -offset 15n
.It Li ".Ad addr1"
.Ad addr1
.It Li ".Ad addr1 ."
.Ad addr1 .
.It Li ".Ad addr1 , file2"
.Ad addr1 , file2
.It Li ".Ad f1 , f2 , f3 :"
.Ad f1 , f2 , f3 :
.It Li ".Ad addr ) ) ,"
.Ad addr ) ) ,
.El
.Pp
.
The default width is 12n.
.
.Ss "Author Name"
.
The
.Ql .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.
.Pp
.Dl Usage: .An Ao author name Ac ...
.Pp
.Bl -tag -width ".Li .An\ \*[q]Joe\ Author\*[q]\ )\ )\ ," -offset 15n
.It Li ".An \*[q]Joe Author\*[q]"
.An "Joe Author"
.It Li ".An \*[q]Joe Author\*[q] ,"
.An "Joe Author" ,
.It Li ".An \*[q]Joe Author\*[q] Aq nobody@FreeBSD.org"
.An "Joe Author" Aq nobody@FreeBSD.org
.It Li ".An \*[q]Joe Author\*[q] ) ) ,"
.An "Joe Author" ) ) ,
.El
.Pp
.
The default width is 12n.
.Pp
In the
.Sx AUTHORS
section, the
.Ql .An
command causes a line break allowing each new name to appear on its own
line.
If this is not desirable,
.
.Bd -literal -offset indent
\&.An \-nosplit
.Ed
.Pp
.
call will turn this off.
To turn splitting back on, write
.
.Bd -literal -offset indent
\&.An \-split
.Ed
.
.Ss "Arguments"
.
The
.Li .Ar
argument macro may be used whenever an argument is referenced.
If called without arguments, the
.Sq Ar
string is output.
.Pp
.Dl Usage: .Ar Oo Ao argument Ac Oc ...
.Pp
.Bl -tag -width ".Li .Ar\ file1\ file2" -compact -offset 15n
.It Li .Ar
.Ar
.It Li ".Ar file1"
.Ar file1
.It Li ".Ar file1 ."
.Ar file1 .
.It Li ".Ar file1 file2"
.Ar file1 file2
.It Li ".Ar f1 f2 f3 :"
.Ar f1 f2 f3 :
.It Li ".Ar file ) ) ,"
.Ar file ) ) ,
.El
.Pp
.
The default width is 12n.
.
.Ss "Configuration Declaration (Section Four Only)"
.
The
.Ql .Cd
macro is used to demonstrate a
.Xr config 8
declaration for a device interface in a section four manual.
.Pp
.Dl Usage: .Cd Ao argument Ac ...
.Pp
.Bl -tag -width ".Li .Cd\ Xdevice\ le0\ at\ scode?X" -offset 15n
.It Li ".Cd \*[q]device le0 at scode?\*[q]"
.Cd "device le0 at scode?"
.El
.Pp
In the
.Sx SYNOPSIS
section a
.Ql .Cd
command causes a line break before and after its arguments are printed.
.Pp
.
The default width is 12n.
.
.Ss "Command Modifiers"
.
The command modifier is identical to the
.Ql .Fl
(flag) command with the exception that the
.Ql .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
.Sx Flags .
.Pp
The default width is 10n.
.
.Ss "Defined Variables"
.
A variable (or constant) which is defined in an include file
is specified by the macro
.Ql .Dv .
.Pp
.Dl Usage: .Dv Ao defined variable Ac ...
.Pp
.Bl -tag -width ".Li .Dv\ MAXHOSTNAMELEN" -compact -offset 15n
.It Li ".Dv MAXHOSTNAMELEN"
.Dv MAXHOSTNAMELEN
.It Li ".Dv TIOCGPGRP )"
.Dv TIOCGPGRP )
.El
.Pp
.
The default width is 12n.
.
.Ss Errno's
.
The
.Ql .Er
errno macro specifies the error return value for section 2, 3, and\~9 library
routines.
The second example below shows
.Ql .Er
used with the
.Ql .Bq
general text domain macro, as it would be used in a section two manual page.
.Pp
.Dl Usage: .Er Ao errno type Ac ...
.Pp
.Bl -tag -width ".Li .Bq\ Er\ ENOTDIR" -compact -offset 15n
.It Li ".Er ENOENT"
.Er ENOENT
.It Li ".Er ENOENT ) ;"
.Er ENOENT ) ;
.It Li ".Bq Er ENOTDIR"
.Bq Er ENOTDIR
.El
.Pp
.
The default width is 17n.
.
.Ss "Environment Variables"
.
The
.Ql .Ev
macro specifies an environment variable.
.Pp
.Dl Usage: .Ev Ao argument Ac ...
.Pp
.Bl -tag -width ".Li .Ev\ PRINTER\ )\ )\ ," -compact -offset 15n
.It Li ".Ev DISPLAY"
.Ev DISPLAY
.It Li ".Ev PATH ."
.Ev PATH .
.It Li ".Ev PRINTER ) ) ,"
.Ev PRINTER ) ) ,
.El
.Pp
.
The default width is 15n.
.
.Ss Flags
.
The
.Ql .Fl
macro handles command line flags.
It prepends a dash,
.Ql \- ,
to the flag.
For interactive command flags, which are not prepended with a dash, the
.Ql .Cm
(command modifier)
macro is identical, but without the dash.
.Pp
.Dl Usage: .Fl Ao argument Ac ...
.Pp
.Bl -tag -width ".Li .Fl\ xyz\ )\ ," -compact -offset 15n
.It Li .Fl
.Fl
.It Li ".Fl cfv"
.Fl cfv
.It Li ".Fl cfv ."
.Fl cfv .
.It Li ".Cm cfv ."
.Cm cfv .
.It Li ".Fl s v t"
.Fl s v t
.It Li ".Fl \- ,"
.Fl \- ,
.It Li ".Fl xyz ) ,"
.Fl xyz ) ,
.It Li ".Fl |"
.Fl |
.El
.Pp
The
.Ql .Fl
macro without any arguments results in a dash representing stdin/stdout.
Note that giving
.Ql .Fl
a single dash will result in two dashes.
.Pp
The default width is 12n.
.
.Ss "Function Declarations"
.
The
.Ql .Fd
macro is used in the
.Sx SYNOPSIS
section with section two or three functions.
It is neither callable nor parsed.
.Pp
.Dl Usage: .Fd Ao argument Ac ...
.Pp
.Bl -tag -width ".Li .Fd\ X#include\ <sys/types.h>X" -compact -offset 15n
.It Li ".Fd \*[q]#include <sys/types.h>\*[q]"
.Fd "#include <sys/types.h>"
.El
.Pp
In the
.Sx SYNOPSIS
section a
.Ql .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.
.
.Pp
The
.Ql .In
macro, while in the
.Sx SYNOPSIS
section, represents the
.Li #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.
.Pp
While not in the
.Sx SYNOPSIS
section, it represents the header file enclosed in angle brackets.
.Pp
.Dl Usage: .In Ao header file Ac
.Pp
.Bl -tag -width ".Li .In\ stdio.h" -compact -offset 15n
.nr in-synopsis-section 1
.It Li ".In stdio.h"
.In stdio.h
.nr in-synopsis-section 0
.It Li ".In stdio.h"
.In stdio.h
.El
.
.Ss "Function Types"
.
This macro is intended for the
.Sx 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
.Sx SYNOPSIS
of sections two and three (it causes a line break, allowing the function
name to appear on the next line).
.Pp
.Dl Usage: .Ft Ao type Ac ...
.Pp
.Bl -tag -width ".Li .Ft\ struct\ stat" -compact -offset 15n
.It Li ".Ft struct stat"
.Ft struct stat
.El
.
.Ss "Functions (Library Routines)"
.
The 
.Ql .Fn
macro is modeled on
.Tn ANSI\~C
conventions.
.Pp
.Dl Usage: .Fn Ao function Ac Oo Ao parameter Ac Oc ...
.Pp
.Bl -tag -width ".Li .Fn\ align\ Xchar\ *ptrX\ ," -compact -offset 15n
.It Li ".Fn getchar"
.Fn getchar
.It Li ".Fn strlen ) ,"
.Fn strlen ) ,
.It Li ".Fn align \*[q]char *ptr\*[q] ,"
.Fn align "char *ptr" ,
.El
.Pp
Note that any call to another macro signals the end of the
.Ql .Fn
call (it will insert a closing parenthesis at that point).
.Pp
For functions with many parameters (which is rare), the macros
.Ql .Fo
(function open)
and
.Ql .Fc
(function close)
may be used with
.Ql .Fa
(function argument).
.Pp
Example:
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
.
Produces:
.
.Bd -ragged -offset indent
.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
.Ed
.Pp
.
In the
.Sx SYNOPSIS
section, the function will always begin at the beginning of line.
If there is more than one function presented in the
.Sx 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.
.Pp
The default width values of
.Ql .Fn
and
.Ql .Fo
are 12n and 16n, respectively.
.
.Ss "Function Arguments"
.
The
.Ql .Fa
macro is used to refer to function arguments (parameters) outside of the
.Sx SYNOPSIS
section of the manual or inside the
.Sx SYNOPSIS
section if the enclosure macros
.Ql .Fo
and
.Ql .Fc
instead of
.Ql .Fn
are used.
.Ql .Fa
may also be used to refer to structure members.
.Pp
.Dl Usage: .Fa Ao function argument Ac ...
.Pp
.Bl -tag -width ".Li .Fa\ d_namlen\ )\ )\ ," -compact -offset 15n
.It Li ".Fa d_namlen ) ) ,"
.Fa d_namlen ) ) ,
.It Li ".Fa iov_len"
.Fa iov_len
.El
.Pp
.
The default width is 12n.
.
.Ss "Return Values"
.
The
.Ql .Rv
macro generates text for use in the
.Sx RETURN VALUES
section.
.Pp
.Dl Usage: .Rv Oo \-std Oc Op Ao function Ac ...
.Pp
For example,
.Ql ".Rv \-std atexit"
produces:
.
.Bd -ragged -offset indent
\# a small hack to suppress a warning message
.ds section-old "\*[section]
.ds section 3
.Rv -std atexit
.ds section "\*[section-old]
.Ed
.Pp
.
The
.Fl std
option is valid only for manual page sections\~2 and\~3.
Currently, this macro does nothing if used without the
.Fl std
flag.
.
.Ss "Exit Status"
.
The
.Ql .Ex
macro generates text for use in the
.Sx DIAGNOSTICS
section.
.Pp
.Dl Usage: .Ex Oo \-std Oc Op Ao utility Ac ...
.Pp
For example,
.Ql ".Ex \-std cat"
produces:
.
.Bd -ragged -offset indent
\# a small hack to suppress a warning message
.ds section-old "\*[section]
.ds section 1
.Ex -std cat
.ds section "\*[section-old]
.Ed
.Pp
.
The
.Fl std
option is valid only for manual page sections 1, 6 and\~8.
Currently, this macro does nothing if used without the
.Fl std
flag.
.
.Ss "Interactive Commands"
.
The
.Ql .Ic
macro designates an interactive or internal command.
.Pp
.Dl Usage: .Ic Ao argument Ac ...
.Pp
.Bl -tag -width ".Li .Ic\ setenv\ ,\ unsetenv" -compact -offset 15n
.It Li ".Ic :wq"
.Ic :wq
.It Li ".Ic \*[q]do while {...}\*[q]"
.Ic "do while {...}"
.It Li ".Ic setenv , unsetenv"
.Ic setenv , unsetenv
.El
.Pp
.
The default width is 12n.
.
.Ss "Library Names"
.
The
.Ql .Lb
macro is used to specify the library where a particular function is compiled
in.
.Pp
.Dl Usage: .Lb Ao argument Ac ...
.Pp
Available arguments to
.Ql .Lb 
and their results are:
.
.Pp
.Bl -tag -width ".Li libossaudio" -compact -offset indent
.It Li libarm
.Lb libarm
.It Li libarm32
.Lb libarm32
.It Li libc
.Lb libc
.It Li libcdk
.Lb libcdk
.It Li libcompat
.Lb libcompat
.It Li libcrypt
.Lb libcrypt
.It Li libcurses
.Lb libcurses
.It Li libedit
.Lb libedit
.It Li libevent
.Lb libevent
.It Li libform
.Lb libform
.It Li libi386
.Lb libi386
.It Li libintl
.Lb libintl
.It Li libipsec
.Lb libipsec
.It Li libkvm
.Lb libkvm
.It Li libm
.Lb libm
.It Li libm68k
.Lb libm68k
.It Li libmagic
.Lb libmagic
.It Li libmenu
.Lb libmenu
.It Li libossaudio
.Lb libossaudio
.It Li libpam
.Lb libpam
.It Li libpcap
.Lb libpcap
.It Li libpci
.Lb libpci
.It Li libpmc
.Lb libpmc
.It Li libposix
.Lb libposix
.It Li libpthread
.Lb libpthread
.It Li libresolv
.Lb libresolv
.It Li librt
.Lb librt
.It Li libtermcap
.Lb libtermcap
.It Li libusbhid
.Lb libusbhid
.It Li libutil
.Lb libutil
.It Li libx86_64
.Lb libx86_64
.It Li libz
.Lb libz
.El
.Pp
.
Local, OS-specific additions might be found in the file
.Pa mdoc.local ;
look for strings named
.Ql str\-Lb\-XXX .
.Ql XXX
then denotes the keyword to be used with the
.Ql .Lb
macro.
.Pp
In the
.Sx LIBRARY
section an
.Ql .Lb
command causes a line break before and after its arguments are printed.
.Pp
.
.Ss Literals
.
The
.Ql .Li
literal macro may be used for special characters, variable constants, etc.\&
\- anything which should be displayed as it would be typed.
.Pp
.Dl Usage: .Li Ao argument Ac ...
.Pp
.Bl -tag -width ".Li .Li\ cntrl\-D\ )\ ,"  -compact -offset 15n
.It Li ".Li \een"
.Li \en
.It Li ".Li M1 M2 M3 ;"
.Li M1 M2 M3 ;
.It Li ".Li cntrl\-D ) ,"
.Li cntrl-D ) ,
.It Li ".Li 1024 ..."
.Li 1024 ...
.El
.Pp
.
The default width is 16n.
.
.Ss Names
.
The
.Ql .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,
.Ql .Nm
regurgitates this initial name for the sole purpose of making less work for
the author.
.Ql .Nm
causes a line break within the
.Sx SYNOPSIS
section.
.Pp
Note: A section two or three document function name is addressed with the
.Ql .Nm
in the
.Sx NAME
section, and with
.Ql .Fn
in the
.Sx SYNOPSIS
and remaining sections.
For interactive commands, such as the
.Ql while
command keyword in
.Xr csh 1 ,
the
.Ql .Ic
macro should be used.
While
.Ql .Ic
is nearly identical
to
.Ql .Nm ,
it can not recall the first argument it was invoked with.
.Pp
.Dl Usage: .Nm Oo Ao argument Ac Oc ...
.Pp
.Bl -tag -width ".Li .Nm\ groff_mdoc" -compact -offset 15n
.It Li ".Nm groff_mdoc"
.Nm groff_mdoc
.It Li ".Nm \e\-mdoc"
.Nm \-mdoc
.It Li ".Nm foo ) ) ,"
.Nm foo ) ) ,
.It Li ".Nm :"
.Nm :
.El
.Pp
.
The default width is 10n.
.
.Ss Options
.
The
.Ql .Op
macro places option brackets around any remaining arguments on the
command line, and places any trailing punctuation outside the brackets.
The macros
.Ql .Oo
and
.Ql .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.
.Pp
.Dl Usage: .Op Oo Ao option Ac Oc ...
.Pp
.Bl -tag -width ".Li .Op\ Fl\ c\ Ar\ objfil\ Op\ Ar\ corfil\ ," -compact -offset 15n
.It Li .Op
.Op
.It Li ".Op Fl k"
.Op Fl k
.It Li ".Op Fl k ) ."
.Op Fl k ) .
.It Li ".Op Fl k Ar kookfile"
.Op Fl k Ar kookfile
.It Li ".Op Fl k Ar kookfile ,"
.Op Fl k Ar kookfile ,
.It Li ".Op Ar objfil Op Ar corfil"
.Op Ar objfil Op Ar corfil
.It Li ".Op Fl c Ar objfil Op Ar corfil ,"
.Op Fl c Ar objfil Op Ar corfil ,
.It Li ".Op word1 word2"
.Op word1 word2
.It Li ".Li .Op Oo Ao option Ac Oc ..."
.Li .Op Oo Ao option Ac Oc ...
.El
.Pp
Here a typical example of the
.Ql .Oo
and
.Ql .Oc
macros:
.
.Bd -literal -offset indent
\&.Oo
\&.Op Fl k Ar kilobytes
\&.Op Fl i Ar interval
\&.Op Fl c Ar count
\&.Oc
.Ed
.Pp
.
Produces:
.
.Bd -filled -offset indent
.Oo
.Op Fl k Ar kilobytes
.Op Fl i Ar interval
.Op Fl c Ar count
.Oc
.Ed
.Pp
.
The default width values of
.Ql .Op
and
.Ql .Oo
are 14n and 10n, respectively.
.
.Ss Pathnames
.
The
.Ql .Pa
macro formats path or file names.
If called without arguments, the
.Sq Pa
string is output, which represents the current user's home directory.
.Pp
.Dl Usage: .Pa Oo Ao pathname Ac Oc ...
.Pp
.Bl -tag -width ".Li .Pa\ /tmp/fooXXXXX\ )\ ." -compact -offset 15n
.It Li .Pa
.Pa
.It Li ".Pa /usr/share"
.Pa /usr/share
.It Li ".Pa /tmp/fooXXXXX ) ."
.Pa /tmp/fooXXXXX ) .
.El
.Pp
.
The default width is 32n.
.
.Ss Standards
.
The
.Ql .St
macro replaces standard abbreviations with their formal names.
.Pp
.Dl Usage: .St Ao abbreviation Ac ...
.Pp
Available pairs for
.Dq Abbreviation/Formal Name
are:
.
.Pp
.Tn ANSI/ISO C
.Pp
.Bl -tag -width ".Li \-p1003.1g\-2000" -compact -offset indent
.It Li \-ansiC
.St -ansiC
.It Li \-ansiC\-89
.St -ansiC-89
.It Li \-isoC
.St -isoC
.It Li \-isoC\-90
.St -isoC-90
.It Li \-isoC\-99
.St -isoC-99
.El
.Pp
.
.Tn POSIX
Part 1: System API
.Pp
.Bl -tag -width ".Li \-p1003.1g\-2000" -compact -offset indent
.It Li \-iso9945\-1\-90
.St -iso9945-1-90
.It Li \-iso9945\-1\-96
.St -iso9945-1-96
.It Li \-p1003.1
.St -p1003.1
.It Li \-p1003.1\-88
.St -p1003.1-88
.It Li \-p1003.1\-90
.St -p1003.1-90
.It Li \-p1003.1\-96
.St -p1003.1-96
.It Li \-p1003.1b\-93
.St -p1003.1b-93
.It Li \-p1003.1c\-95
.St -p1003.1c-95
.It Li \-p1003.1g\-2000
.St -p1003.1g-2000
.It Li \-p1003.1i\-95
.St -p1003.1i-95
.It Li \-p1003.1\-2001
.St -p1003.1-2001
.It Li \-p1003.1\-2004
.St -p1003.1-2004
.It Li \-p1003.1\-2008
.St -p1003.1-2008
.El
.Pp
.
.Tn POSIX
Part 2: Shell and Utilities
.Pp
.Bl -tag -width ".Li \-p1003.1g\-2000" -compact -offset indent
.It Li \-iso9945\-2\-93
.St -iso9945-2-93
.It Li \-p1003.2
.St -p1003.2
.It Li \-p1003.2\-92
.St -p1003.2-92
.It Li \-p1003.2a\-92
.St -p1003.2a-92
.El
.Pp
.
X/Open
.Pp
.Bl -tag -width ".Li \-p1003.1g\-2000" -compact -offset indent
.It Li \-susv2
.St -susv2
.It Li \-susv3
.St -susv3
.It Li \-svid4
.St -svid4
.It Li \-xbd5
.St -xbd5
.It Li \-xcu5
.St -xcu5
.It Li \-xcurses4.2
.St -xcurses4.2
.It Li \-xns5
.St -xns5
.It Li \-xns5.2
.St -xns5.2
.It Li \-xpg3
.St -xpg3
.It Li \-xpg4
.St -xpg4
.It Li \-xpg4.2
.St -xpg4.2
.It Li \-xsh5
.St -xsh5
.El
.Pp
.
Miscellaneous
.Pp
.Bl -tag -width ".Li \-p1003.1g\-2000" -compact -offset indent
.It Li \-ieee754
.St -ieee754
.It Li \-iso8802\-3
.St -iso8802-3
.El
.
.Ss "Variable Types"
.
The
.Ql .Vt
macro may be used whenever a type is referenced.
In the
.Sx SYNOPSIS
section, it causes a line break (useful for old style variable declarations).
.Pp
.Dl Usage: .Vt Ao type Ac ...
.Pp
.Bl -tag -width ".Li .Vt\ extern\ char\ *optarg\ ;" -compact -offset 15n
.It Li ".Vt extern char *optarg ;"
.Vt extern char *optarg ;
.It Li ".Vt FILE *"
.Vt FILE *
.El
.
.Ss Variables
.
Generic variable reference.
.Pp
.Dl Usage: .Va Ao variable Ac ...
.Pp
.Bl -tag -width ".Li .Va\ Xchar\ sX\ ]\ )\ )\ ," -compact -offset 15n
.It Li ".Va count"
.Va count
.It Li ".Va settimer ,"
.Va settimer ,
.It Li ".Va \*[q]int *prt\*[q] ) :"
.Va "int *prt" ) :
.It Li ".Va \*[q]char s\*[q] ] ) ) ,"
.Va "char s" ] ) ) ,
.El
.Pp
.
The default width is 12n.
.
.Ss "Manual Page Cross References"
.
The
.Ql .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.
.Pp
.Dl Usage: .Xr Ao man page name Ac Oo Ao section Ac Oc ...
.Pp
.Bl -tag -width ".Li .Xr\ xinit\ 1x\ ;" -compact -offset 15n
.It Li ".Xr mdoc"
.Xr mdoc
.It Li ".Xr mdoc ,"
.Xr mdoc ,
.It Li ".Xr mdoc 7"
.Xr mdoc 7
.It Li ".Xr xinit 1x ;"
.Xr xinit 1x ;
.El
.Pp
.
The default width is 10n.
.
.
.Sh "GENERAL TEXT DOMAIN"
.
.Ss "AT&T Macro"
.
.Pp
.Dl Usage: .At Oo Ao version Ac Oc ...
.Pp
.Bl -tag -width ".Li .At\ v6\ ." -compact -offset 15n
.It Li .At
.At
.It Li ".At v6 ."
.At v6 .
.El
.Pp
The following values for
.Ao version Ac
are possible:
.Pp
.Dl 32v, v1, v2, v3, v4, v5, v6, v7, V, V.1, V.2, V.3, V.4
.
.Ss "BSD Macro"
.
.Pp
.Dl "Usage: .Bx" Bro \-alpha | \-beta | \-devel Brc ...
.Dl "       .Bx" Oo Ao version Ac Oo Ao release Ac Oc Oc ...
.Pp
.Bl -tag -width ".Li .Bx\ -devel" -compact -offset 15n
.It Li .Bx
.Bx
.It Li ".Bx 4.3 ."
.Bx 4.3 .
.It Li ".Bx \-devel"
.Bx -devel
.El
.Pp
.Ao version Ac
will be prepended to the string
.Sq Bx .
The following values for
.Ao release Ac
are possible:
.Pp
.Dl Reno, reno, Tahoe, tahoe, Lite, lite, Lite2, lite2
.
.Ss "NetBSD Macro"
.
.Pp
.Dl Usage: .Nx Oo Ao version Ac Oc ...
.Pp
.Bl -tag -width ".Li .Nx\ 1.4\ ." -compact -offset 15n
.It Li .Nx
.Nx
.It Li ".Nx 1.4 ."
.Nx 1.4 .
.El
.Pp
For possible values of
.Ao version Ac
see the description of the
.Ql .Os
command above in section
.Sx "TITLE MACROS" .
.
.Ss "FreeBSD Macro"
.
.Pp
.Dl Usage: .Fx Oo Ao version Ac Oc ...
.Pp
.Bl -tag -width ".Li .Fx\ 2.2\ ." -compact -offset 15n
.It Li .Fx
.Fx
.It Li ".Fx 2.2 ."
.Fx 2.2 .
.El
.Pp
For possible values of
.Ao version Ac
see the description of the
.Ql .Os
command above in section
.Sx "TITLE MACROS" .
.
.Ss "DragonFly Macro"
.
.Pp
.Dl Usage: .Dx Oo Ao version Ac Oc ...
.Pp
.Bl -tag -width ".Li .Dx\ 1.4\ ." -compact -offset 15n
.It Li .Dx
.Dx
.It Li ".Dx 1.4 ."
.Dx 1.4 .
.El
.Pp
For possible values of
.Ao version Ac
see the description of the
.Ql .Os
command above in section
.Sx "TITLE MACROS" .
.
.Ss "OpenBSD Macro"
.
.Pp
.Dl Usage: .Ox Oo Ao version Ac Oc ...
.Pp
.Bl -tag -width ".Li .Ox\ 1.0" -compact -offset 15n
.It Li ".Ox 1.0"
.Ox 1.0
.El
.
.Ss "BSD/OS Macro"
.
.Pp
.Dl Usage: .Bsx Oo Ao version Ac Oc ...
.Pp
.Bl -tag -width ".Li .Bsx\ 1.0" -compact -offset 15n
.It Li ".Bsx 1.0"
.Bsx 1.0
.El
.
.Ss "UNIX Macro"
.
.Pp
.Dl Usage: .Ux ...
.Pp
.Bl -tag -width ".Li .Ux" -compact -offset 15n
.It Li .Ux
.Ux
.El
.
.Ss "Emphasis Macro"
.
Text may be stressed or emphasized with the
.Ql .Em
macro.
The usual font for emphasis is italic.
.Pp
.Dl Usage: .Em Ao argument Ac ...
.Pp
.Bl -tag -width ".Li .Em\ vide\ infra\ )\ )\ ," -compact -offset 15n
.It Li ".Em does not"
.Em does not
.It Li ".Em exceed 1024 ."
.Em exceed 1024 .
.It Li ".Em vide infra ) ) ,"
.Em vide infra ) ) ,
.El
.Pp
.
The default width is 10n.
.
.Ss "Font Mode"
.
The
.Ql .Bf
font mode must be ended with the
.Ql .Ef
macro (the latter takes no arguments).
Font modes may be nested within other font modes.
.Pp
.Ql .Bf
has the following syntax:
.Pp
.Dl .Bf Ao font mode Ac
.Pp
.Ao font mode Ac
must be one of the following three types:
.Pp
.Bl -tag -width ".Sy \&Sy | Fl symbolic" -compact -offset indent
.It Sy \&Em | Fl emphasis
Same as if the 
.Ql .Em
macro was used for the entire block of text.
.It Sy \&Li | Fl literal
Same as if the
.Ql .Li
macro was used for the entire block of text.
.It Sy \&Sy | Fl symbolic
Same as if the
.Ql .Sy
macro was used for the entire block of text.
.El
.Pp
Both macros are neither callable nor parsed.
.
.Ss "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
.Ql 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
.Ql o
and
.Ql c
respectively.
.Pp
\# XXX
.if t \
.  ne 10
.
.Bd -filled -offset 4n
.Bl -column "quote" "close" "open" "Angle Bracket Enclosure" "`string' or string"
.Em Quote Ta Em Open Ta Em Close Ta Em Function               Ta Em Result
.No .Aq   Ta    .Ao  Ta    .Ac   Ta "Angle Bracket Enclosure" Ta Ao string Ac
.No .Bq   Ta    .Bo  Ta    .Bc   Ta "Bracket Enclosure"       Ta Bo string Bc
.No .Brq  Ta    .Bro Ta    .Brc  Ta "Brace Enclosure"         Ta Bro string Brc
.No .Dq   Ta    .Do  Ta    .Dc   Ta "Double Quote"            Ta Do string Dc
.No .Eq   Ta    .Eo  Ta    .Ec   Ta "Enclose String (in XX)"  Ta XXstringXX
.No .Pq   Ta    .Po  Ta    .Pc   Ta "Parenthesis Enclosure"   Ta Po string Pc
.No .Ql   Ta         Ta          Ta "Quoted Literal"          Ta So string Sc or Li string
.No .Qq   Ta    .Qo  Ta    .Qc   Ta "Straight Double Quote"   Ta Qo string Qc
.No .Sq   Ta    .So  Ta    .Sc   Ta "Single Quote"            Ta So string Sc
.El
.Ed
.Pp
All macros ending with
.Sq q
and
.Sq o
have a default width value of 12n.
.
.Bl -tag -width ".Li .Ec , .Eo"
.It Li .Eo , .Ec
These macros expect the first argument to be the opening and closing strings
respectively.
.It Li .Es , .En
Due to the nine-argument limit in the original troff program two other
macros have been implemented which are now rather obsolete:
.Ql .Es
takes the first and second parameter as the left and right enclosure string,
which are then used to enclose the arguments of
.Ql .En .
The default width value is 12n for both macros.
.It Li .Eq
The first and second arguments of this macro are the opening and
closing strings respectively, followed by the arguments to be enclosed.
.It Li .Ql
The quoted literal macro behaves differently in troff and nroff mode.
If formatted with
.Xr 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.
.Pp
The default width is 16n.
.It Li .Pf
The prefix macro suppresses the whitespace between its first and second
argument:
.
.Bl -tag -width ".Li .Pf\ (\ Fa\ name2" -offset indent
.It Li ".Pf ( Fa name2"
.Pf ( Fa name2
.El
.Pp
.
The default width is 12n.
.Pp
The
.Ql .Ns
macro (see below) performs the analogous suffix function.
.It Li .Ap
The
.Ql .Ap
macro inserts an apostrophe and exits any special text modes, continuing in
.Ql .No
mode.
.El
.Pp
.
Examples of quoting:
.
.Pp
.Bl -tag -width ".Li .Bq\ Em\ Greek\ ,\ French\ ." -compact -offset indent
.It Li .Aq
.Aq
.It Li ".Aq Pa ctype.h ) ,"
.Aq Pa ctype.h ) ,
.It Li .Bq
.Bq
.It Li ".Bq Em Greek , French ."
.Bq Em Greek , French .
.It Li .Dq
.Dq
.It Li ".Dq string abc ."
.Dq string abc .
.It Li ".Dq \'^[A\-Z]\'"
.Dq \'^[A-Z]\'
.It Li ".Ql man mdoc"
.Ql man mdoc
.It Li .Qq
.Qq
.It Li ".Qq string ) ,"
.Qq string ) ,
.It Li ".Qq string Ns ),"
.Qq string Ns ),
.It Li .Sq
.Sq
.It Li ".Sq string"
.Sq string
.It Li ".Em or Ap ing"
.Em or Ap ing
.El
.Pp
.
For a good example of nested enclosure macros, see the
.Ql .Op
option macro.
It was created from the same underlying enclosure macros as those presented
in the list above.
The
.Ql .Xo
and
.Ql .Xc
extended argument list macros are discussed below.
.
.Ss "No-Op or Normal Text Macro"
.
The
.Ql .No
macro can be used in a macro command line for parameters which should
.Em not
be formatted.
Be careful to add
.Ql \e&
to the word
.Ql \&No
if you really want that English word (and not the macro) as a parameter.
.Pp
.Dl Usage: .No Ao argument Ac ...
.Pp
.Bl -tag -width ".Li .No\ test\ Ta\ with\ Ta\ tabs" -compact -offset 15n
.It Li ".No test Ta with Ta tabs"
.No test Ta with Ta tabs
.El
.Pp
.
The default width is 12n.
.
.Ss "No-Space Macro"
.
The
.Ql .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:
.Pp
.Dl "Usage:" ... Ao argument Ac \&Ns Oo Ao argument Ac Oc ...
.Dl "      " .Ns Ao argument Ac ...
.Pp
.Bl -tag -width ".Li .Op\ Fl\ I\ Ns\ Ar\ directory" -compact -offset 15n
.It Li ".Op Fl I Ns Ar directory"
.Op Fl I Ns Ar directory
.El
.Pp
Note: The
.Ql .Ns
macro always invokes the
.Ql .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
.Sq Usage
line),
.Ql .Ns
is identical to
.Ql .No .
.
.Ss "Section Cross References"
.
The
.Ql .Sx
macro designates a reference to a section header within the same document.
.Pp
.Dl Usage: .Sx Ao section reference Ac ...
.Pp
.Bl -tag -width ".Li .Sx\ FILES" -offset 15n
.It Li ".Sx FILES"
.Sx FILES
.El
.Pp
.
The default width is 16n.
.
.Ss Symbolics
.
The symbolic emphasis macro is generally a boldface macro in either the
symbolic sense or the traditional English usage.
.Pp
.Dl Usage: .Sy Ao symbol Ac ...
.Pp
.Bl -tag -width ".Li .Sy\ Important\ Notice" -compact -offset 15n
.It Li ".Sy Important Notice"
.Sy Important Notice
.El
.Pp
.
The default width is 6n.
.
.Ss Mathematical Symbols
.
Use this macro for mathematical symbols and similar things.
.Pp
.Dl Usage: .Ms Ao math symbol Ac ...
.Pp
.Bl -tag -width ".Li .Ms\ sigma" -compact -offset 15n
.It Li ".Ms sigma"
.Ms sigma
.El
.Pp
.
The default width is 6n.
.
.Ss "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
.Xr refer 1
style references.
.Pp
.Bl -tag -width 6n -offset indent -compact
.It Li .Rs
Reference start (does not take arguments).
Causes a line break in the
.Sx "SEE ALSO"
section and begins collection of reference information until the reference
end macro is read.
.It Li .Re
Reference end (does not take arguments).
The reference is printed.
.It Li .%A
Reference author name; one name per invocation.
.It Li .%B
Book title.
.It Li .%C
City/place (not implemented yet).
.It Li .%D
Date.
.It Li .%I
Issuer/publisher name.
.It Li .%J
Journal name.
.It Li .%N
Issue number.
.It Li .%O
Optional information.
.It Li .%P
Page number.
.It Li .%Q
Corporate or foreign author.
.It Li .%R
Report name.
.It Li .%T
Title of article.
.It Li .%U
Optional hypertext reference.
.It Li .%V
Volume.
.El
.Pp
Macros beginning with
.Ql %
are not callable but accept multiple arguments in the usual way.
Only the
.Ql .Tn
macro is handled properly as a parameter; other macros will cause strange
output.
.Ql .%B
and
.Ql .%T
can be used outside of the
.Ql .Rs/.Re
environment.
.Pp
Example:
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
produces
.
.Bd -ragged -offset indent
.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
.Ed
.
.Ss "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.
.Pp
.Dl Usage: .Tn Ao symbol Ac ...
.Pp
.Bl -tag -width ".Li .Tn\ ASCII" -compact -offset 15n
.It Li ".Tn DEC"
.Tn DEC
.It Li ".Tn ASCII"
.Tn ASCII
.El
.Pp
.
The default width is 10n.
.
.Ss "Extended Arguments"
.
The
.Li .Xo
and
.Li .Xc
macros allow one to extend an argument list on a macro boundary for the
.Ql .It
macro (see below).
Note that
.Li .Xo
and
.Li .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.
.Pp
Here is an example of
.Ql .Xo
using the space mode macro to turn spacing off:
.
.Bd -literal -offset indent
\&.Sm off
\&.It Xo Sy I Ar operation
\&.No \een Ar count No \een
\&.Xc
\&.Sm on
.Ed
.Pp
.
produces
.
.Bd -filled -offset indent
.Bl -tag -compact
.Sm off
.It Xo Sy I Ar operation
.No \en Ar count No \en
.Xc
.Sm on
.El
.Ed
.Pp
.
Another one:
.
.Bd -literal -offset indent
\&.Sm off
\&.It Cm S No / Ar old_pattern Xo
\&.No / Ar new_pattern
\&.No / Op Cm g
\&.Xc
\&.Sm on
.Ed
.Pp
.
produces
.
.Bd -filled -offset indent
.Bl -tag -compact
.Sm off
.It Cm S No \&/ Ar old_pattern Xo
.No \&/ Ar new_pattern
.No \&/ Op Cm g
.Xc
.Sm on
.El
.Ed
.Pp
.
Another example of
.Ql .Xo
and enclosure macros: Test the value of a variable.
.
.Bd -literal -offset indent
\&.It Xo
\&.Ic .ifndef
\&.Oo \e&! Oc Ns Ar variable Oo
\&.Ar operator variable ...
\&.Oc Xc
.Ed
.Pp
.
produces
.
.Bd -filled -offset indent
.Bl -tag -width flag -compact
.It Xo
.Ic .ifndef
.Oo \&! Oc Ns Ar variable Oo
.Ar operator variable ...
.Oc Xc
.El
.Ed
.Pp
.
.
.Sh "PAGE STRUCTURE DOMAIN"
.
.Ss "Section Headers"
.
The following
.Ql .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
.Ql .Sh
macro is parsed but not generally callable.
It can be used as an argument in a call to
.Ql .Sh
only; it then reactivates the default font for
.Ql .Sh .
.Pp
The default width is 8n.
.
.Bl -tag -width ".Li .Sh\ RETURN\ VALUES"
.It Li ".Sh NAME"
The
.Ql ".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
.Sx NAME
section consists of at least three items.
The first is the
.Ql .Nm
name macro naming the subject of the man page.
The second is the name description macro,
.Ql .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.
.Pp
.Ql .Nd
first prints
.Ql \- ,
then all its arguments.
.
.It Li ".Sh LIBRARY"
This section is for section two and three function calls.
It should consist of a single
.Ql .Lb
macro call;
see
.Sx "Library Names" .
.
.It Li ".Sh SYNOPSIS"
The
.Sx SYNOPSIS
section describes the typical usage of the subject of a man page.
The macros required are either
.Ql .Nm ,
.Ql .Cd ,
or
.Ql .Fn
(and possibly
.Ql .Fo ,
.Ql .Fc ,
.Ql .Fd ,
and
.Ql .Ft ) .
The function name macro
.Ql .Fn
is required for manual page sections\~2 and\~3; the command and general name
macro
.Ql .Nm
is required for sections 1, 5, 6, 7, and\~8.
Section\~4 manuals require a
.Ql .Nm ,
.Ql .Fd
or a
.Ql .Cd
configuration device usage macro.
Several other macros may be necessary to produce the synopsis line as shown
below:
.
.Bd -filled -offset indent
.Nm cat
.Op Fl benstuv
.Op Fl
.Ar
.Ed
.Pp
.
The following macros were used:
.Pp
.Dl ".Nm cat"
.Dl ".Op Fl benstuv"
.Dl ".Op Fl"
.Dl .Ar
.
.It Li ".Sh DESCRIPTION"
In most cases the first text in the
.Sx 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
.Ql .Bl
(begin list),
.Ql .It
(list item) and
.Ql .El
(end list)
macros are used (see
.Sx Lists and Columns
below).
.
.It Li ".Sh IMPLEMENTATION NOTES"
Implementation specific information should be placed here.
.
.It Li ".Sh RETURN VALUES"
Sections 2, 3 and\~9 function return values should go here.
The
.Ql .Rv
macro may be used to generate text for use in the
.Sx RETURN VALUES
section for most section 2 and 3 library functions;
see
.Sx "Return Values" .
.El
.Pp
.
The following
.Ql .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.
.
.Bl -tag -width ".Li .Sh\ COMPATIBILITY"
.It Li ".Sh ENVIRONMENT"
The
.Sx ENVIRONMENT
section should reveal any related environment variables and clues to their
behavior and/or usage.
.
.It Li ".Sh FILES"
Files which are used or created by the man page subject should be listed via
the
.Ql .Pa
macro in the
.Sx FILES
section.
.
.It Li ".Sh EXAMPLES"
There are several ways to create examples.
See the
.Sx EXAMPLES
section below for details.
.
.It Li ".Sh DIAGNOSTICS"
Diagnostic messages from a command should be placed in this section.
The
.Ql .Ex
macro may be used to generate text for use in the
.Sx DIAGNOSTICS
section for most section 1, 6 and\~8 commands;
see
.Sx "Exit Status" .
.
.It Li ".Sh COMPATIBILITY"
Known compatibility issues (e.g. deprecated options or parameters)
should be listed here.
.
.It Li ".Sh ERRORS"
Specific error handling, especially from library functions (man page
sections 2, 3, and\~9) should go here.
The
.Ql .Er
macro is used to specify an error (errno).
.
.It Li ".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
.Sx "SEE ALSO"
section.
Cross references are specified using the
.Ql .Xr
macro.
Currently
.Xr refer 1
style references are not accommodated.
.Pp
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:
.Pp
.Xr ls 1 ,
.Xr ps 1 ,
.Xr group 5 ,
.Xr passwd 5
.
.It Li ".Sh STANDARDS"
If the command, library function or file adheres to a specific
implementation such as
.St -p1003.2
or
.St -ansiC
this should be noted here.
If the command does not adhere to any standard, its history should be noted
in the
.Sx HISTORY
section.
.
.It Li ".Sh HISTORY"
Any command which does not adhere to any specific standards should be
outlined historically in this section.
.
.It Li ".Sh AUTHORS"
Credits should be placed here.
Use the
.Ql .An
macro for names and the
.Ql .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.
.It Li ".Sh BUGS"
Blatant problems with the topic go here.
.El
.Pp
.
User-specified
.Ql .Sh
sections may be added; for example, this section was set with:
.
.Bd -literal -offset 15n
\&.Sh "PAGE STRUCTURE DOMAIN"
.Ed
.
.Ss "Subsection Headers"
.
Subsection headers have exactly the same syntax as section headers:
.Ql .Ss
is parsed but not generally callable.
It can be used as an argument in a call to
.Ql .Ss
only; it then reactivates the default font for
.Ql .Ss .
.Pp
The default width is 8n.
.
.Ss "Paragraphs and Line Spacing"
.
.Bl -tag -width ".Li .Pp"
.It Li .Pp
The 
.Ql .Pp
paragraph command may be used to specify a line space where necessary.
The macro is not necessary after a
.Ql .Sh
or
.Ql .Ss
macro or before a
.Ql .Bl
or
.Ql .Bd
macro (which both assert a vertical distance unless the
.Fl compact
flag is given).
.Pp
The macro is neither callable nor parsed and takes no arguments; an
alternative name is
.Ql .Lp .
.El
.
.\" XXX
.
.\" This worked with version one, need to redo for version three
.\" .Pp
.\" .Ds I
.\" .Cw (ax+bx+c) \ is\ produced\ by\ \&
.\" .\".Cw (ax+bx+c) \&.Va_by_) \&_and_\& \&[?/]m_b1_e1_f1[?/]\&
.\" .Cl Cx \t\t
.\" .Li \&.Cx\ (
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Va ax
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Sy \+
.\" .Cx
.\" .Cl Cx \&(\&
.\" .Va ax
.\" .Cx +
.\" .Va by
.\" .Cx +
.\" .Va c )
.\" .Cx \t
.\" .Em is produced by
.\" .Cx \t
.\" .Li \&.Va by
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Sy \+
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Va c )
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Cx
.\" .Cx
.\" .Cw
.\" .De
.\" .Pp
.\" This example shows the same equation in a different format.
.\" The spaces
.\" around the
.\" .Li \&+
.\" signs were forced with
.\" .Li \e :
.\" .Pp
.\" .Ds I
.\" .Cw (ax\ +\ bx\ +\ c) \ is\ produced\ by\ \&
.\" .\".Cw (ax+bx+c) \&.Va_by_) \&_and_\& \&[?/]m_b1_e1_f1[?/]\&
.\" .Cl Cx \t\t
.\" .Li \&.Cx\ (
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Va a
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Sy x
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Cx \e\ +\e\ \e&
.\" .Cx
.\" .Cl Cx \&(\&
.\" .Va a
.\" .Sy x
.\" .Cx \ +\ \&
.\" .Va b
.\" .Sy y
.\" .Cx \ +\ \&
.\" .Va c )
.\" .Cx \t
.\" .Em is produced by
.\" .Cl Cx \t\t
.\" .Li \&.Va b
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Sy y
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Cx \e\ +\e\ \e&
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Va c )
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Cx
.\" .Cx
.\" .Cw
.\" .De
.\" .Pp
.\" The incantation below was
.\" lifted from the
.\" .Xr adb 1
.\" manual page:
.\" .Pp
.\" .Ds I
.\" .Cw \&[?/]m_b1_e1_f1[?/]\& is\ produced\ by
.\" .Cl Cx \t\t
.\" .Li \&.Cx Op Sy ?/
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Nm m
.\" .Cx
.\" .Cl Cx Op Sy ?/
.\" .Nm m
.\" .Ad \ b1 e1 f1
.\" .Op Sy ?/
.\" .Cx \t
.\" .Em is produced by
.\" .Cx \t
.\" .Li \&.Ar \e\ b1 e1 f1
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Op Sy ?/
.\" .Cx
.\" .Cl Cx \t\t
.\" .Li \&.Cx
.\" .Cx
.\" .Cw
.\" .De
.\" .Pp
.
.Ss Keeps
.
The only keep that is implemented at this time is for words.
The macros are
.Ql .Bk
(begin keep)
and
.Ql .Ek
(end keep).
The only option that
.Ql .Bk
accepts currently is
.Fl words
(this is also the default if no option is given) which is useful for
preventing line breaks in the middle of options.
In the example for the make command line arguments (see
.Sx What's in a Name ) ,
the keep prevented
.Xr nroff
from placing up the flag and the argument on separate lines.
.Pp
Both macros are neither callable nor parsed.
.Pp
More work needs to be done with the keep macros; specifically, a
.Fl line
option should be added.
.
.Ss "Examples and Displays"
.
There are seven types of displays.
.Pp
.Bl -tag -width ".Li .D1"
.It Li .D1
(This is D-one.)
Display one line of indented text.
This macro is parsed but not callable.
.Pp
.D1 Fl ldghfstru
.Pp
The above was produced by:
.Li ".D1 Fl ldghfstru" .
.
.It Li .Dl
(This is D-ell.)
Display one line of indented
.Em literal
text.
The
.Ql .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).
.Ql .Dl
is parsed but not callable.
.Pp
.Dl % ls \-ldg /usr/local/bin
.Pp
The above was produced by:
.Li ".Dl % ls \e\-ldg /usr/local/bin" .
.
.It Li .Bd
Begin display.
The
.Ql .Bd
display must be ended with the
.Ql .Ed
macro.
It has the following syntax:
.Pp
.Bd -ragged -compact
.Bl -tag -width ".Li .Bd" -offset indent
.It Li .Bd Xo
.Bro \-literal | \-filled | \-unfilled | \-ragged | \-centered Brc
.Oo \-offset Ao string Ac Oc Oo \-file Ao file name Ac Oc Oo \-compact Oc Xc
.El
.Ed
.Pp
.
.Bl -tag -width ".Fl file Ao Ar file name Ac " -compact
.It Fl ragged
Fill, but do not adjust the right margin (only left-justify).
.It Fl centered
Center lines between the current left and right margin.
Note that each single line is centered.
.It Fl 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.
.It Fl filled
Display a filled block.
The block of text is formatted (i.e., the text is justified on both the left
and right side).
.It Fl literal
Display block with literal font (usually fixed-width).
Useful for source code or simple tabbed or spaced text.
.It Fl file Ao Ar file name Ac
The file whose name follows the
.Fl file
flag is read and displayed before any data enclosed with
.Ql .Bd
and
.Ql .Ed ,
using the selected display type.
Any
.Xr troff/ Ns Nm \-mdoc
commands in the file will be processed.
.It Fl offset Ao Ar string Ac
If
.Fl 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:
.
.Pp
.Bl -tag -width ".Ar indent-two" -compact
.It Ar left
Align block on the current left margin; this is the default mode of
.Ql .Bd .
.It Ar center
Supposedly center the block.
At this time unfortunately, the block merely gets left aligned about an
imaginary center margin.
.It Ar indent
Indent by one default indent value or tab.
The default indent value is also used for the
.Ql .D1
and 
.Ql .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).
.It Ar indent\-two
Indent two times the default indent value.
.It Ar right
This
.Em 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
.Xr troff .
.El
.Pp
.
If
.Ao string Ac
is a valid numeric expression instead
.Pf ( Em with a scale indicator other than
.Sq Em u ) ,
use that value for indentation.
The most useful scale indicators are
.Sq m
and
.Sq n ,
specifying the so-called
.Em \&Em
and
.Em "En square" .
This is approximately the width of the letters
.Sq m
and
.Sq n
respectively
of the current font (for nroff output, both scale indicators give the same
values).
If
.Ao string Ac
isn't a numeric expression, it is tested whether it is an
.Nm \-mdoc
macro name, and the default offset value associated with this macro is used.
Finally, if all tests fail,
the width of
.Ao string Ac
(typeset with a fixed-width font) is taken as the offset.
.It Fl compact
Suppress insertion of vertical space before begin of display.
.El
.
.It Li .Ed
End display (takes no arguments).
.El
.
.Ss "Lists and Columns"
.
There are several types of lists which may be initiated with the
.Ql .Bl
begin-list macro.
Items within the list are specified with the
.Ql .It
item macro, and each list must end with the
.Ql .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.
.Pp
In addition, several list attributes may be specified such as the width of a
tag, the list offset, and compactness (blank lines between items allowed or
disallowed).
Most of this document has been formatted with a tag style list
.Pf ( Fl tag ) .
.Pp
It has the following syntax forms:
.
.Pp
.Bd -ragged -compact
.Bl -tag -width ".Li .Bl" -offset indent -compact
.It Li .Bl Xo
.Bro \-hang | \-ohang | \-tag | \-diag | \-inset Brc
.Oo \-width Ao string Ac Oc
.Oo \-offset Ao string Ac Oc Oo \-compact Oc Xc
.It Li .Bl Xo
.No \-column Oo \-offset Ao string Ac Oc
.Ao string1 Ac Ao string2 Ac ... Xc
.It Li .Bl Xo
.Bro \-item | \-enum Oo \-nested Oc | \-bullet | \-hyphen | \-dash Brc
.Oo \-offset Ao string Ac Oc Oo \-compact Oc Xc
.El
.Ed
.Pp
.
And now a detailed description of the list types.
.
.Pp
.Bl -tag -width ".Fl column" -compact
.It Fl bullet
A bullet list.
.
.Bd -literal -offset indent
\&.Bl \-bullet \-offset indent \-compact
\&.It
Bullet one goes here.
\&.It
Bullet two here.
\&.El
.Ed
.Pp
.
Produces:
.
.Pp
.Bl -bullet -offset indent -compact
.It
Bullet one goes here.
.It
Bullet two here.
.El
.Pp
.
.It Fl dash No ( or Fl hyphen )
A dash list.
.
.Bd -literal -offset indent
\&.Bl \-dash \-offset indent \-compact
\&.It
Dash one goes here.
\&.It
Dash two here.
\&.El
.Ed
.Pp
.
Produces:
.
.Pp
.Bl -dash -offset indent -compact
.It
Dash one goes here.
.It
Dash two here.
.El
.Pp
.
.It Fl enum
An enumerated list.
.
.Bd -literal -offset indent
\&.Bl \-enum \-offset indent \-compact
\&.It
Item one goes here.
\&.It
And item two here.
\&.El
.Ed
.Pp
.
The result:
.
.Pp
.Bl -enum -offset indent -compact
.It
Item one goes here.
.It
And item two here.
.El
.Pp
.
If you want to nest enumerated lists, use the
.Fl nested
flag (starting with the second-level list):
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
.
Result:
.
.Pp
.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
.Pp
.
.It Fl item
A list of type
.Fl item
without list markers.
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
.
Produces:
.
.Pp
.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
.Pp
.
.It Fl tag
A list with tags.
Use
.Fl width
to specify the tag width.
.
.Pp
.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
.Pp
.
The raw text:
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
.
.It Fl diag
Diag lists create section four diagnostic lists and are similar to inset
lists except callable macros are ignored.
The
.Fl width
flag is not meaningful in this context.
.Pp
Example:
.
.Bd -literal -offset indent
\&.Bl \-diag
\&.It You can't use Sy here.
The message says all.
\&.El
.Ed
.Pp
.
produces
.
.Bl -diag
.It You can't use Sy here.
The message says all.
.El
.Pp
.
.It Fl hang
A list with hanging tags.
.
.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
.Pp
And the unformatted text which created it:
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
.
.It Fl ohang
Lists with overhanging tags do not use indentation for the items; tags are
written to a separate line.
.Pp
.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
.Pp
.
The raw text:
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
.
.It Fl inset
Here is an example of inset labels:
.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.
Use a
.Fl width
attribute as described below.
.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
.Pp
Here is the source text which produced the above example:
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
.
.It Fl column
This list type generates multiple columns.
The number of columns and the width of each column is determined by the
arguments to the
.Fl column
list,
.Aq Ar string1 ,
.Aq Ar string2 ,
etc.
If
.Aq Ar stringN
starts with a
.Ql .\&
(dot) immediately followed by a valid
.Nm \-mdoc
macro name, interpret
.Aq Ar stringN
and use the width of the result.
Otherwise, the width of
.Aq Ar stringN
(typeset with a fixed-width font) is taken as the
.Ar N Ns th
column width.
.Pp
Each
.Ql .It
argument is parsed to make a row, each column within the row is a separate
argument separated by a tab or the
.Ql .Ta
macro.
.Pp
The table:
.
.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
.Pp
.
was produced by:
.
.Bd -literal
\&.Bl \-column \-offset indent ".Sy String" ".Sy Nroff" ".Sy Troff"
\&.It Sy String Ta Sy Nroff Ta Sy Troff
\&.It Li <= Ta <= Ta \e*(<=
\&.It Li >= Ta >= Ta \e*(>=
\&.El
.Ed
.Pp
.
Don't abuse this list type!
For more complicated cases it might be far better and easier to use
.Xr tbl 1 ,
the table preprocessor.
.El
.Pp
.
Other keywords:
.
.Bl -tag -width ".Fl indent Ao Ar string Ac"
.It Fl width Ao Ar string Ac
If
.Aq Ar string
starts with a
.Ql .\&
(dot) immediately followed by a valid
.Nm \-mdoc
macro name, interpret
.Aq Ar string
and use the width of the result.
Almost all lists in this document use this option.
.Pp
Example:
.
.Bd -literal -offset indent
\&.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
.Ed
.Pp
.
gives:
.
.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
.Pp
.
(Note that the current state of
.Nm \-mdoc
is saved before
.Aq Ar string
is interpreted; afterwards, all variables are restored again.
However, boxes (used for enclosures) can't be saved in
.Tn GNU
.Xr troff 1 ;
as a consequence, arguments must always be
.Em balanced
to avoid nasty errors.
For example, do not write
.Ql ".Ao Ar string"
but
.Ql ".Ao Ar string Xc"
instead if you really need only an opening angle bracket.)
.Pp
Otherwise, if
.Aq Ar string
is a valid numeric expression
.Em ( with a scale indicator other than
.Sq Em u ) ,
use that value for indentation.
The most useful scale indicators are
.Sq m
and
.Sq n ,
specifying the so-called
.Em \&Em
and
.Em "En square" .
This is approximately the width of the letters
.Sq m
and
.Sq n
respectively
of the current font (for nroff output, both scale indicators give the same
values).
If
.Aq Ar string
isn't a numeric expression, it is tested whether it is an
.Nm \-mdoc
macro name, and the default width value associated with this macro is used.
Finally, if all tests fail,
the width of
.Aq Ar string
(typeset with a fixed-width font) is taken as the width.
.Pp
If a width is not specified for the tag list type, every time
.Ql .It
is invoked, an attempt is made to determine an appropriate width.
If the first argument to
.Ql .It
is a callable macro, the default width for that macro will be used;
otherwise, the default width of
.Ql .No
is used.
.It Fl offset Ao Ar string Ac
If
.Aq Ar string
is
.Ar indent ,
a default indent value (normally set to\~6n, similar to the value used in
.Ql .Dl
or
.Ql .Bd )
is used.
If
.Aq Ar string
is a valid numeric expression instead
.Pf ( Em with a scale indicator other than
.Sq Em u ) ,
use that value for indentation.
The most useful scale indicators are
.Sq m
and
.Sq n ,
specifying the so-called
.Em \&Em
and
.Em "En square" .
This is approximately the width of the letters
.Sq m
and
.Sq n
respectively
of the current font (for nroff output, both scale indicators give the same
values).
If
.Aq Ar string
isn't a numeric expression, it is tested whether it is an
.Nm \-mdoc
macro name, and the default offset value associated with this macro is used.
Finally, if all tests fail,
the width of
.Aq Ar string
(typeset with a fixed-width font) is taken as the offset.
.It Fl compact
Suppress insertion of vertical space before the list and between list items.
.El
.
.
.Sh "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:
.Ql .Me
and
.Ql .Ot .
They are documented here for completeness \- if you know how to use them
properly please send a mail to
.Mt bug-groff@gnu.org
(including an example).
.
.Bl -tag -width ".Li .Bt"
.It Li .Bt
prints
.
.Bd -ragged -offset indent
.Bt
.Ed
.Pp
It is neither callable nor parsed and takes no arguments.
.
.It Li .Fr
.Pp
.Dl Usage: .Fr Ao function return value Ac ...
.Pp
Don't use this macro.
It allows a break right before the return value (usually a single digit)
which is bad typographical behaviour.
Use
.Ql \e~
to tie the return value to the previous word.
.
.It Li .Hf
Use this macro to include a (header) file literally.
It first prints
.Ql File:
followed by the file name, then the contents of
.Ao file Ac .
.Pp
.Dl Usage: .Hf Ao file Ac
.Pp
It is neither callable nor parsed.
.
.It Li .Lk
To be written.
.
.It Li .Me
Exact usage unknown.
The documentation in the
.Nm \-mdoc
source file describes it as a macro for
.Dq "menu entries" .
.Pp
Its default width is 6n.
.
.It Li .Mt
To be written.
.
.It Li .Ot
Exact usage unknown.
The documentation in the
.Nm \-mdoc
source file describes it as
.Dq old function type (fortran) .
.
.It Li .Sm
Activate (toggle) space mode.
.Pp
.Dl Usage: .Sm Oo on | off Oc ...
.Pp
If space mode is off, no spaces between macro arguments are inserted.
If called without a parameter (or if the next parameter is neither
.Ql on
nor
.Ql off ,
.Ql .Sm
toggles space mode.
.
.It Li .Ud
prints
.
.Bd -ragged -offset indent
.Ud
.Ed
.Pp
It is neither callable nor parsed and takes no arguments.
.El
.
.
.Sh "PREDEFINED STRINGS"
.
The following strings are predefined:
.Pp
.Bl -column String infinity "Troff " "straight double quote" -offset indent
.It Sy String Ta Sy Nroff Ta Sy Troff Ta Sy Meaning
.It Li <=     Ta <=       Ta \*[<=]   Ta "less equal"
.It Li >=     Ta >=       Ta \*[>=]   Ta "greater equal"
.It Li Rq     Ta ''       Ta \*[Rq]   Ta "right double quote"
.It Li Lq     Ta ``       Ta \*[Lq]   Ta "left double quote"
.It Li ua     Ta ^        Ta \*[ua]   Ta "upwards arrow"
.It Li aa     Ta \'       Ta \*[aa]   Ta "acute accent"
.It Li ga     Ta \`       Ta \*[ga]   Ta "grave accent"
.It Li q      Ta \&"      Ta \*[q]    Ta "straight double quote"
.It Li Pi     Ta pi       Ta \*[Pi]   Ta "greek pi"
.It Li Ne     Ta !=       Ta \*[Ne]   Ta "not equal"
.It Li Le     Ta <=       Ta \*[Le]   Ta "less equal"
.It Li Ge     Ta >=       Ta \*[Ge]   Ta "greater equal"
.It Li Lt     Ta <        Ta \*[Lt]   Ta "less than"
.It Li Gt     Ta >        Ta \*[Gt]   Ta "greater than"
.It Li Pm     Ta +\-      Ta \*[Pm]   Ta "plus minus"
.It Li If     Ta infinity Ta \*[If]   Ta "infinity"
.It Li Am     Ta \*[Am]   Ta \*[Am]   Ta "ampersand"
.It Li Na     Ta \*[Na]   Ta \*[Na]   Ta "not a number"
.It Li Ba     Ta \*[Ba]   Ta \*[Ba]   Ta "vertical bar"
.El
.Pp
The names of the columns
.Sy Nroff
and
.Sy Troff
are a bit misleading;
.Sy Nroff
shows the
.Tn ASCII
representation, while
.Sy Troff
gives the best glyph form available.
For example, a Unicode enabled
.Tn TTY Ns - Ns
device will have proper glyph representations for all strings, whereas the
enhancement for a Latin1
.Tn TTY Ns - Ns
device is only the plus-minus sign.
.Pp
String names which consist of two characters can be written as
.Ql \e*(xx ;
string names which consist of one character can be written as
.Ql \e*x .
A generic syntax for a string name of any length is
.Ql \e*[xxx]
(this is a
.Tn GNU
.Xr troff 1
extension).
.
.
\#
\#=====================================================================
\#
.Sh DIAGNOSTICS
.
The debugging macro
.Ql .Db
available in previous versions of
.Nm \-mdoc
has been removed since
.Tn GNU
.Xr 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.
.Pp
The only remaining debugging macro is
.Ql .Rd
which yields a register dump of all global registers and strings.
A normal user will never need it.
.
.
.Sh "FORMATTING WITH GROFF, TROFF, AND NROFF"
.
By default, the package inhibits page breaks, headers, and footers if
displayed with a
.Tn TTY
device like
.Sq latin1
or
.Sq unicode ,
to make the manual more efficient for viewing on-line.
This behaviour can be changed (e.g.\& to create a hardcopy of the
.Tn TTY
output) by setting the register
.Ql cR
to zero while calling
.Xr groff 1 ,
resulting in multiple pages instead of a single, very long page:
.Pp
.Dl groff \-Tlatin1 \-rcR=0 \-mdoc foo.man > foo.txt
.Pp
For double-sided printing, set register
.Ql D
to\~1:
.Pp
.Dl groff \-Tps \-rD1 \-mdoc foo.man > foo.ps
.Pp
To change the document font size to 11pt or 12pt, set register
.Ql S
accordingly:
.Pp
.Dl groff \-Tdvi \-rS11 \-mdoc foo.man > foo.dvi
.Pp
Register
.Ql S
is ignored for
.Tn TTY
devices.
.Pp
The line and title length can be changed by setting the registers
.Ql LL
and
.Ql LT ,
respectively:
.Pp
.Dl groff \-Tutf8 \-rLL=100n \-rLT=100n \-mdoc foo.man | less
.Pp
If not set, both registers default to 78n for TTY devices and 6.5i
otherwise.
.
.
.Sh FILES
.
.Bl -tag -width mdoc/doc-ditroff -compact
.It Pa doc.tmac
The main manual macro package.
.It Pa mdoc.tmac
A wrapper file to call
.Pa doc.tmac .
.It Pa mdoc/doc-common
Common strings, definitions, stuff related typographic output.
.It Pa mdoc/doc-nroff
Definitions used for a
.Tn TTY
output device.
.It Pa mdoc/doc-ditroff
Definitions used for all other devices.
.It Pa mdoc.local
Local additions and customizations.
.It Pa andoc.tmac
Use this file if you don't know whether the 
.Nm \-mdoc
or the
.Nm \-man
package should be used.
Multiple man pages (in either format) can be handled.
.El
.
.
.Sh "SEE ALSO"
.
.Xr groff 1 ,
.Xr man 1 ,
.Xr troff 1 ,
.Xr groff_man 7
.
.
.Sh BUGS
.
Section 3f has not been added to the header routines.
.Pp
.Ql \&.Nm
font should be changed in
.Sx NAME
section.
.Pp
.Ql \&.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.
.Pp
The list and display macros do not do any keeps
and certainly should be able to.
.\" Note what happens if the parameter list overlaps a newline
.\" boundary.
.\" to make sure a line boundary is crossed:
.\" .Bd -literal
.\" \&.Fn struct\e\ dictionarytable\e\ *dictionarylookup struct\e\ dictionarytable\e\ *tab[]
.\" .Ed
.\" .Pp
.\" produces, nudge nudge,
.\" .Fn struct\ dictionarytable\ *dictionarylookup char\ *h struct\ dictionarytable\ *tab[] ,
.\" .Fn struct\ dictionarytable\ *dictionarylookup char\ *h struct\ dictionarytable\ *tab[] ,
.\" nudge
.\" .Fn struct\ dictionarytable\ *dictionarylookup char\ *h struct\ dictionarytable\ *tab[] .
.\" .Pp
.\" If double quotes are used, for example:
.\" .Bd -literal
.\" \&.Fn \*qstruct dictionarytable *dictionarylookup\*q \*qchar *h\*q \*qstruct dictionarytable *tab[]\*q
.\" .Ed
.\" .Pp
.\" produces, nudge nudge,
.\" .Fn "struct dictionarytable *dictionarylookup" "char *h" "struct dictionarytable *tab[]" ,
.\" nudge
.\" .Fn "struct dictionarytable *dictionarylookup" "char *h" "struct dictionarytable *tab[]" ,
.\" nudge
.\" .Fn "struct dictionarytable *dictionarylookup" "char *h" "struct dictionarytable *tab[]" .
.\" .Pp
.\" Not a pretty sight...
.\" In a paragraph, a long parameter containing unpaddable spaces as
.\" in the former example will cause
.\" .Xr troff
.\" to break the line and spread
.\" the remaining words out.
.\" The latter example will adjust nicely to
.\" justified margins, but may break in between an argument and its
.\" declaration.
.\" In
.\" .Xr nroff
.\" the right margin adjustment is normally ragged and the problem is
.\" not as severe.
.
.\" Local Variables:
.\" mode: nroff
.\" End: