MDOC.SAMPLES(7) MachTen Reference Manual MDOC.SAMPLES(7)

NAME
mdoc.samples - tutorial sampler for writing BSD UNIX manuals with -mdoc

SYNOPSIS
man mdoc.samples

DESCRIPTION
A tutorial sampler for writing BSD UNIX manual pages with the -mdoc macro
package, a content-based and domain-based formatting package for
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 BSD 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. It is
hoped 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
Since a tutorial document is normally read when a person desires to use
the material immediately, the assumption has been made that the user of
this document may be impatient. The material presented in the remained
of this document is outlined as follows:

1. TROFF IDIOSYNCRASIES
Macro Usage.
Passing Space Characters in an Argument.
Trailing Blank Space Characters (a warning).
Escaping Special Characters.

2. THE ANATOMY OF A MAN PAGE
A manual page template.

3. INTRODUCTION OF TITLE MACROS.

4. INTRODUCTION OF MANUAL AND GENERAL TEXT DOMAINS.
What’s in a name....
General Syntax.

5. MANUAL DOMAIN
Addresses.
Arguments.
Configuration Declarations (section four only).
Command Modifier .
Defined Variables.
Errno’s (Section two only).
Environment Variables.
Function Argument.

Function Declaration.
Flags.
Functions (library routines).
Function Types.
Interactive Commands.
Literals.
Names.
Options.
Pathnames.
Variables.
Cross References.

6. GENERAL TEXT DOMAIN
AT&T Macro.
BSD Macro.
UNIX Macro.
Emphasis Macro.
Enclosure/Quoting Macros
Angle Bracket Quote/Enclosure.
Bracket Quotes/Enclosure.
Double Quote macro/Enclosure.
Parenthesis Quote/Enclosure.
Single Quotes/Enclosure.
Prefix Macro.
Extended Arguments.
No-Op or Normal Text Macro.
No Space Macro.
Section Cross References.
Symbolic Macro.
References and Citations.
Trade Names (Acronyms and Type Names).

7. PAGE STRUCTURE DOMAIN
Section Headers.
Paragraphs and Line Spacing.
Keeps.
Displays.
Lists and Columns.

8. PREDEFINED STRINGS

9. DIAGNOSTICS

10. FORMATTING WITH GROFF, TROFF AND NROFF

11. BUGS

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

Macro Usage
As in troff(1), a macro is called by placing a ‘.’ (dot character) at
the beginning of a line followed by the two character name for the macro.
Arguments may follow the macro separated by spaces. It is the dot char-
acter at the beginning of the line which causes troff(1) to interpret the
next two characters as a macro name. To place a ‘.’ (dot character) at
the beginning of a line in some context other than a macro invocation,
precede the ‘.’ (dot) with the ‘’ escape sequence. The ‘’ translates
literally to a zero width space, and is never displayed in the output.

In general, troff(1) macros accept up to nine arguments, any extra argu-
ments are ignored. Most macros in -mdoc accept nine arguments and, in
limited cases, arguments may be continued or extended on the next line
(See Extensions). A few 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 is determined to be callable will be exe-
cuted or called when it is processed. In this case the argument, al-
though the name of a macro, is not preceded by a ‘.’ (dot). It is in
this manner that many macros are nested; 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 two character 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 and in the companion quick refer-
ence manual mdoc(7). 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.

Passing Space Characters in an Argument
Sometimes it is desirable to give as one argument a string containing one
or more blank space characters. This may be necessary to defeat the nine
argument limit or to specify arguments to macros which expect particular
arrangement of items in the argument list. For example, the function
macro ‘.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. Implementation note: Unfortunately, the most convenient way
of passing spaces in between quotes by reassigning individual arguments
before parsing was fairly expensive speed wise and space wise to imple-
ment in all the macros for AT&T troff. It is not expensive for groff but
for the sake of portability, has been limited to the following macros
which need it the most:

Cd Configuration declaration (section 4 SYNOPSIS)
Bl Begin list (for the width specifier).
Em Emphasized text.
Fn Functions (sections two and four).
It List items.
Li Literal text.
Sy Symbolic text.
%B Book titles.
%J Journal names.
%O Optional notes for a reference.
%R Report title (in a reference).
%T Title of article in a book or journal.

One way of passing a string containing blank spaces is to use the hard or
unpaddable space character ‘ ’, that is, a blank space preceded by the
escape character ‘´. This method may be used with any macro but has the
side effect of interfering with the adjustment of text over the length of
a line. Troff sees the hard space as if it were any other printable
character and cannot split the string into blank or newline separated
pieces as one would expect. The method is useful for strings which are
not expected to overlap a line boundary. 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 ‘´ or quotes were omitted, ‘.Fn’ would see three arguments and
the result would be:

fetch(char, *str)

For an example of what happens when the parameter list overlaps a newline
boundary, see the BUGS section.

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
force a blank character at the end of a line, it may be forced with an
unpaddable space and the ‘’ escape character. For example,
‘string ’.

Escaping Special Characters
Special characters like the newline character ‘0, are handled by re-
placing the ‘´ with ‘\’ (e.g. ‘\n’) to preserve the backslash.

THE ANATOMY OF A MAN PAGE
The body of a man page is easily constructed from a basic template found
in the file:

.
.
.Dd Month day, year
.Os OPERATING_SYSTEM [version/release]
.Dt DOCUMENT_TITLE [section number] [volume]
.Sh NAME
.Sh SYNOPSIS
.Sh DESCRIPTION
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

The first items in the template are the macros (.Dd, .Os, .Dt); the docu-
ment date, the operating system the man page or subject source is devel-
oped or modified for, and the man page title (in upper case) along with
the section of the manual the page belongs in. These macros identify the
page, and are discussed below in TITLE MACROS.

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

TITLE MACROS
The title macros are the first portion of the page structure domain, but
are presented first and separate 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 one called once at the very beginning of the document
and are used to construct the headers and footers only.

.Dt DOCUMENT_TITLE section# [volume]
The document title is the subject of the man page and must be in
CAPITALS due to troff limitations. The section number may be
1, ..., 8, and if it is specified, the volume title may be omit-
ted. A volume title may be arbitrary or one of the following:

AMD UNIX Ancestral Manual Documents
SMM UNIX System Manager’s Manual
URM UNIX Reference Manual
PRM UNIX Programmer’s Manual

The default volume labeling is URM for sections 1, 6, and 7; SMM
for section 8; PRM for sections 2, 3, 4, and 5.

.Os operating_system release#
The name of the operating system should be the common acronym,
e.g. BSD or ATT. The release should be the standard release
nomenclature for the system specified, e.g. 4.3, 4.3+Tahoe, V.3,
V.4. Unrecognized arguments are displayed as given in the page
footer. For instance, a typical footer might be:

.Os BSD 4.3

or for a locally produced set

.Os CS Department

The Berkeley default, ‘.Os’ without an argument, has been defined
as BSD Experimental in the site specific file
/usr/src/share/tmac/doc-common. It really should default to
LOCAL. Note, if the ‘.Os’ macro is not present, the bottom left
corner of the page will be ugly.

.Dd month day, year
The date should be written formally:

January 25, 1989

MANUAL DOMAIN
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 request 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:

.Va argument1 argument2 ... argument9

The ‘.Va’ is a macro command or request, and anything following it is an
argument 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 arguments. The macros which formatted the
above example:

.Nm filter
.Op Fl flag
.Ar infile outfile

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

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

Here one might talk about the command make and qualify the argument
makefile, as an argument to the flag, -f, or discuss the optional file
operand target. In the verbal context, such detail can prevent confusion,
however the -mdoc package does not have a macro for an argument to a
flag. Instead the ‘Ar’ argument macro is used for an operand or file ar-
gument 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=value
.Bk -words
.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: ‘.Ar’, ‘.Fl’, ‘.Nm’, and ‘.Pa’ differ only
when called without arguments; ‘.Fn’ and ‘.Xr’ impose an order on their
argument lists and the ‘.Op’ and ‘.Fn’ macros have nesting limitations.
All content macros are capable of recognizing and properly handling punc-
tuation, provided each punctuation character is separated by a leading
space. If an request is given:

.Li sptr, ptr),

The result is:

sptr, ptr),

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

.Li sptr , ptr ) ,

The result is:

sptr, ptr),

The punctuation is now recognized and is output in the default font dis-
tinguishing it from the strings in literal font.

To remove the special meaning from a punctuation character escape it with
‘’. Troff is limited as a macro language, and has difficulty when pre-
sented with a string containing a member of the mathematical, logical or
quotation set:

{+,-,/,*,%,<,>,<=,>=,=,==,&,‘,’,"}

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

Address Macro
The address macro identifies an address construct of the form ad-
dr1[,addr2[,addr3]].

Usage: .Ad address ... { . , ; : ( ) [ ]}
.Ad addr1 addr1
.Ad addr1 . addr1.
.Ad addr1 , file2 addr1, file2
.Ad f1 , f2 , f3 : f1, f2, f3:
.Ad addr ) ) , addr)),

It is an error to call .Ad without arguments. .Ad is callable by other
macros and is parsed.

Argument Macro
The .Ar argument macro may be used whenever a command line argument is
referenced.

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)),

If .Ar is called without arguments ‘file ...’ is assumed. The .Ar macro
is parsed and is callable.

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. This macro accepts quoted argu-
ments (double quotes only).

device le0 at scode? produced by: ‘.Cd device le0 at scode?’.

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

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

Usage: .Dv defined_variable ... { . , ; : ( ) [ ]}
.Dv MAXHOSTNAMELEN MAXHOSTNAMELEN
.Dv TIOCGPGRP ) TIOCGPGRP)

It is an error to call ‘.Dv’ without arguments. ‘.Dv’ is parsed and is
callable.

Errno’s (Section two only)
The ‘.Er’ errno macro specifies the error return value for section two
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 ERRNOTYPE ... { . , ; : ( ) [ ]}
.Er ENOENT ENOENT
.Er ENOENT ) ; ENOENT);
.Bq Er ENOTDIR [ENOTDIR]

It is an error to call ‘.Er’ without arguments. The ‘.Er’ macro is
parsed and is callable.

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

Usage: .Ev argument ... { . , ; : ( ) [ ]}
.Ev DISPLAY DISPLAY
.Ev PATH . PATH.
.Ev PRINTER ) ) , PRINTER)),

It is an error to call ‘.Ev’ without arguments. The ‘.Ev’ macro is
parsed and is callable.

Function Argument
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
should a parameter list be too long for the ‘.Fn’ macro and the enclosure
macros ‘.Fo’ and ‘.Fc’ must be 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

It is an error to call ‘.Fa’ without arguments. ‘.Fa’ is parsed and is
callable.

Function Declaration
The ‘.Fd’ macro is used in the SYNOPSIS section with section two or three
functions. The ‘.Fd’ macro does not call other macros and is not
callable by other macros.

Usage: .Fd include_file (or defined variable)

In the SYNOPSIS section a ‘.Fd’ request 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.

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.
.Fl s v t -s -v -t
.Fl - , --,
.Fl xyz ) , -xyz),

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 ‘.Fl’ macro is parsed and is callable.

Functions (library routines)
The .Fn macro is modeled on ANSI C conventions.

Usage: .Fn [type] function [[type] parameters ... { . , ; : ( ) [ ]}]
.Fn getchar getchar()
.Fn strlen ) , strlen()),
.Fn "int align" "const * char *sptrs", int align(const * char *sptrs),

It is an error to call ‘.Fn’ without any arguments. The ‘.Fn’ macro is
parsed and is callable, note that any call to another macro signals the
end of the ‘.Fn’ call (it will close-parenthesis at that point).

For functions that have more than eight parameters (and this is rare),
the macros ‘.Fo’ (function open) and ‘.Fc’ (function close) may be used
with ‘.Fa’ (function argument) to get around the limitation. For example:

.Fo "int 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)

The ‘.Fo’ and ‘.Fc’ macros are parsed and are callable. 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. At
the moment, ‘.Fn’ does not check its word boundaries against troff line
lengths and may split across a newline ungracefully. This will be fixed
in the near future.

Function Type
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 page break allowing the function name to appear on
the next line).

Usage: .Ft type ... { . , ; : ( ) [ ]}
.Ft struct stat struct stat

The ‘.Ft’ request is not callable by other macros.

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

Usage: .Li argument ... { . , ; : ( ) [ ]}
.Ic :wq :wq
.Ic do while {...} do while {...}
.Ic setenv , unsetenv setenv, unsetenv

It is an error to call ‘.Ic’ without arguments. The ‘.Ic’ macro is
parsed and is callable.

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

Usage: .Li argument ... { . , ; : ( ) [ ]}
.Li \n
.Li M1 M2 M3 ; M1 M2 M3;
.Li cntrl-D ) , cntrl-D),
.Li 1024 ... 1024 ...

The ‘.Li’ macro is parsed and is callable.

Name Macro
The ‘.Nm’ macro is used for the document title or subject name. It has
the peculiarity of remembering the first argument it was called with,
which should always be the subject name of the page. When called without
arguments, ‘.Nm’ regurgitates this initial name for the sole purpose of
making less work for the author. Note: a section two or three document
function name is addressed with the ‘.Nm’ in the NAME section, and with
‘.Fn’ in the SYNOPSIS and remaining sections. For interactive commands,
such as the ‘while’ command keyword in csh(1), the ‘.Ic’ macro should be
used. While the ‘.Ic’ is nearly identical to ‘.Nm’, it can not recall
the first argument it was invoked with.

Usage: .Nm argument ... { . , ; : ( ) [ ]}
.Nm mdoc.sample mdoc.sample
.Nm −mdoc -mdoc.
.Nm foo ) ) , foo)),
.Nm mdoc.samples

The ‘.Nm’ macro is parsed and is callable.

Options
The ‘.Op’ macro places option brackets around the any remaining arguments
on the command line, and places any trailing punctuation outside the
brackets. The macros ‘.Oc’ and ‘.Oo’ may be used across one or more
lines.

Usage: .Op options ... { . , ; : ( ) [ ]}
.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]

The ‘.Oc’ and ‘.Oo’ macros:

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

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

The macros ‘.Op’, ‘.Oc’ and ‘.Oo’ are parsed and are callable.

Pathnames
The ‘.Pa’ macro formats path or file names.

Usage: .Pa pathname { . , ; : ( ) [ ]}
.Pa /usr/share /usr/share
.Pa /tmp/fooXXXXX ) . /tmp/fooXXXXX).

The ‘.Pa’ macro is parsed and is callable.

Variables
Generic variable reference:

Usage: .Va variable ... { . , ; : ( ) [ ]}
.Va count count
.Va settimer, settimer,
.Va int *prt ) : int *prt):
.Va char s ] ) ) , char s])),

It is an error to call ‘.Va’ without any arguments. The ‘.Va’ macro is
parsed and is callable.

Manual Page Cross References
The ‘.Xr’ macro expects the first argument to be a manual page name, and
the second argument, if it exists, to be either a section page number or
punctuation. Any remaining arguments are assumed to be punctuation.

Usage: .Xr man_page [1,...,8] { . , ; : ( ) [ ]}
.Xr mdoc mdoc
.Xr mdoc , mdoc,
.Xr mdoc 7 mdoc(7)
.Xr mdoc 7 ) ) , mdoc(7))),

The ‘.Xr’ macro is parsed and is callable. It is an error to call ‘.Xr’
without any arguments.

GENERAL TEXT DOMAIN
AT&T Macro
Usage: .At [v6 | v7 | 32v | V.1 | V.4] ... { . , ; : ( ) [ ]}
.At
.At v6 . Version 6 AT&T UNIX.

The ‘.At’ macro is not parsed and not callable. It accepts at most two
arguments.

BSD Macro
Usage: .Bx [Version/release] ... { . , ; : ( ) [ ]}
.Bx BSD UNIX
.Bx 4.3 . 4.3BSD.

The ‘.Bx’ macro is parsed and is callable.

UNIX Macro
Usage: .Ux ... { . , ; : ( ) [ ]}

.Ux UNIX

The ‘.Ux’ macro is parsed and is callable.

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 ‘.Em’ macro is parsed and is callable. It is an error to call ‘.Em’
without arguments.

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. These
can be used across one or more lines of text and while they have nesting
limitations, the one line quote macros can be used inside of them.

Quote Close Open Function Result
.Aq .Ac .Ao Angle Bracket Enclosure <string>
.Bq .Bc .Bo Bracket Enclosure [string]
.Dq .Dc .Do Double Quote ‘‘string’’
.Ec .Eo Enclose String (in XX) XXstringXX
.Pq .Pc .Po Parenthesis Enclosure (string)
.Ql Quoted Literal ‘st’ or string
.Qq .Qc .Qo Straight Double Quote "string"
.Sq .Sc .So Single Quote ‘string’

Except for the irregular macros noted below, all of the quoting macros
are parsed and callable. All handle punctuation properly, as long as it
is presented one character at a time and separated by spaces. The quot-
ing macros examine opening and closing punctuation to determine whether
it comes before or after the enclosing string. This makes some nesting
possible.

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

.Ql The quoted literal macro behaves differently for troff than
nroff. 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.

.Pf The prefix macro is not callable, but it is parsed:

.Pf ( Fa name2
becomes (name2.

The ‘.Ns’ (no space) macro performs the analogous suffix func-
tion.

Examples of quoting:
.Aq <>

.Aq Ar 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’

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 were also built from the same underlying routines and are a good
example of -mdoc macro usage at its worst.

No-Op or Normal Text Macro
The macro .No is a hack for words in a macro command line which should
not be formatted and follows the conventional syntax for content macros.

No Space Macro
The ‘.Ns’ macro eliminates unwanted spaces in between macro requests. It
is useful for old style argument lists where there is no space between
the flag and argument:

.Op Fl I Ns Ar directory produces [-Idirectory]

Note: the ‘.Ns’ macro always invokes the ‘.No’ macro after eliminating
the space unless another macro name follows it. The macro ‘.Ns’ is
parsed and is callable.

Section Cross References
The ‘.Sx’ macro designates a reference to a section header within the
same document. It is parsed and is callable.

.Sx FILES FILES

Symbolic
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 ‘.Sy’ macro is parsed and is callable. Arguments to ‘.Sy’ may be
quoted.

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
style references.

.Rs Reference Start. Causes a line break and begins collection
of reference information until the reference end macro is
read.
.Re Reference End. The reference is printed.
.%A Reference author name, one name per invocation.
.%B Book title.
.%C City/place.
.%D Date.
.%J Journal name.

.%N Issue number.
.%O Optional information.
.%P Page number.
.%R Report name.
.%T Title of article.
.%V Volume(s).

The macros beginning with ‘%’ are not callable, and are parsed only for
the trade name macro which returns to its caller. (And not very pre-
dictably at the moment either.) The purpose is to allow trade names to
be pretty printed in troff/ditroff output.

Trade Names (or Acronyms and Type Names)
The trade name macro is generally a small caps macro for all upper case
words longer than two characters.

Usage: .Tn symbol ... { . , ; : ( ) [ ]}
.Tn DEC DEC
.Tn ASCII ASCII

The ‘.Tn’ macro is parsed and is callable by other macros.

Extended Arguments
The .Xo and .Xc macros allow one to extend an argument list on a macro
boundary. Argument lists cannot be extended within a macro which expects
all of its arguments on one line such as ‘.Op’.

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

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

Produces

Ioperationcount

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 using enclosure macros: Test the value of an
variable.

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

Produces

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

All of the above examples have used the ‘.Xo’ macro on the argument list
of the ‘.It’ (list-item) macro. The extend macros are not used very of-
ten, and when they are it is usually to extend the list-item argument
list. Unfortunately, this is also where the extend macros are the most
finicky. In the first two examples, spacing was turned off; in the
third, spacing was desired in part of the output but not all of it. To
make these macros work in this situation make sure the ‘.Xo’ and ‘.Xc’
macros are placed as shown in the third example. If the ‘.Xo’ macro is
not alone on the ‘.It’ argument list, spacing will be unpredictable. The
‘.Ns’ (no space macro) must not occur as the first or last macro on a
line in this situation. Out of 900 manual pages (about 1500 actual
pages) currently released with BSD UNIX only fifteen use the ‘.Xo’ macro.

PAGE STRUCTURE DOMAIN
Section Headers
The first three ‘.Sh’ section header macros list below 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 can
take up to nine arguments. It is parsed and but is not callable.

.Sh NAME The ‘.Sh NAME’ macro is mandatory. If not specified, the
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 possi-
ble, as the space available is small.

.Sh SYNOPSIS The SYNOPSIS section describes the typical usage of the
subject of a man page. The macros required are either
‘.Nm’, ‘.Cd’, ‘.Fn’, (and possibly ‘.Fo’, ‘.Fc’, ‘.Fd’,
‘.Ft’ macros). 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, 8.
Section 4 manuals require a ‘.Nm, .Fd’ or a ‘.Cd’ configu-
ration 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

Note: The macros ‘.Op’, ‘.Fl’, and ‘.Ar’ recognize the pipe
bar character ‘|’, so a command line such as:

.Op Fl a | Fl b

will not go orbital. Troff normally interprets a | as a
special operator. See PREDEFINED STRINGS for a usable |
character in other situations.

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

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

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

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

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

.Sh 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. At this time refer(1) style references are not
accommodated.

.Sh STANDARDS
If the command, library function or file adheres to a specific
implementation such as IEEE Std1003.2 (‘‘POSIX’’) or ANSI
C3.159-1989 (‘‘ANSI C’’) this should be noted here. If the
command does not adhere to any standard, its history should be
noted in the HISTORY section.

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

.Sh AUTHORS
Credits, if need be, should be placed here.

.Sh DIAGNOSTICS
Diagnostics from a command should be placed in this section.

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

.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 LAYOUT MACROS

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’ macro. (The ‘.Bl’ macro asserts a
vertical distance unless the -compact flag is given).

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 ‘.Bl’
accepts is -words and is useful for preventing line breaks in the middle
of options. In the example for the make command line arguments (see
What’s in a name), the keep prevented nroff from placing up the flag and
the argument on separate lines. (Actually, the option macro used to pre-
vent this from occurring, but was dropped when the decision (religious)
was made to force right justified margins in troff as options in general
look atrocious when spread across a sparse line. More work needs to be
done with the keep macros, a -line option needs to be added.)

Examples and Displays
There are five types of displays, a quickie one line indented display
‘.D1’, a quickie one line literal display ‘.Dl’, and a block literal,
block filled and block ragged which use the ‘.Bd’ begin-display and ‘.Ed’
end-display macros.

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

-ldghfstru

The above was produced by: .Dl -ldghfstru.

.Dl (D-ell) Display one line of indented literal text. The ‘.Dl’ ex-
ample macro has been used throughout this file. It allows the in-
dent (display) of one line of text. Its default font is set to
constant width (literal) however it is parsed and will recognized
other macros. It is not callable however.

% 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. Displays may be nested within displays and lists. ‘.Bd’
has the following syntax:

.Bd display-type [-offset offset_value] [-compact]

The display-type must be one of the following four types and may
have an offset specifier for indentation: ‘.Bd’.

-ragged Display a block of text as typed, right (and
left) margin edges are left ragged.
-filled Display a filled (formatted) block. The block
of text is formatted (the edges are filled - not
left unjustified).
-literal Display a literal block, useful for source code
or simple tabbed or spaced text.
-file file_name The file name following the -file flag is read
and displayed. Literal mode is asserted and
tabs are set at 8 constant width character in-
tervals, however any troff/-mdoc commands in
file will be processed.
-offset string If -offset is specified with one of the follow-
ing strings, the string is interpreted to indi-
cate the level of indentation for the forthcom-
ing 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 Indents by one default indent value
or tab. The default indent value is
also used for the ‘.D1’ display so
one is guaranteed the two types of
displays will line up. This indent
is normally set to 6n or about two
thirds of an inch (six constant
width characters).
indent-two Indents two times the default indent
value.
right This left aligns the block about two
inches from the right side of the
page. This macro needs work and
perhaps may never do the right thing
by troff.

.Ed End-display.

Tagged 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. Columns may be used inside
of lists, but lists are unproven inside of columns.

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). For a change of pace, the list-type used to pre-
sent the list-types is an over-hanging list (-ohang). This type of list
is quite popular with TeX users, but might look a bit funny after having
read many pages of tagged lists. The following list types are accepted
by ‘.Bl’:

-bullet
-item
-enum
These three are the simplest types of lists. Once the ‘.Bl’ macro has
been given, items in the list are merely indicated by a line consisting
solely of the ‘.It’ macro. For example, the source text for a simple
enumerated list would look like:

.Bl -enum -compact
.It
Item one goes here.
.It
And item two here.
.It
Lastly item three goes here.
.El

The results:

1. Item one goes here.
2. And item two here.
3. Lastly item three goes here.

A simple bullet list construction:

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

Produces:

o Bullet one goes here.
o Bullet two here.

-tag
-diag
-hang
-ohang
-inset
These list-types collect arguments specified with the ‘.It’ macro and
create a label which may be inset into the forthcoming text, hanged from
the forthcoming text, overhanged from above and not indented or tagged.
This list was constructed with the ‘-ohang’ list-type. The ‘.It’ macro
is parsed only for the inset, hang and tag list-types and is not
callable. 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.

Diag Diag lists create section four diagnostic lists and are simi-
lar to inset lists except callable macros are ignored.

Hang Hanged labels are a matter of taste.

Ohang Overhanging labels are nice when space is constrained.

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

Here is the source text which produced the above example:

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

Here is a hanged list with just one item:

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

Longer hanged list labels blend in to 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 in to the paragraph unlike
tagged paragraph labels.
.El

The tagged list which follows uses an optional width specifier to control
the width of the tag.

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

The raw text:

.Bl -tag -width "PAGEIN" -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 process priority
(non-positive when in non-interruptible wait)
.El

Acceptable width specifiers:

-width Fl sets the width to the default width for a flag. All
callable macros have a default width value. The
‘.Fl’, value is presently set to ten constant width
characters or about five sixth of an inch.

-width 24n sets the width to 24 constant width characters or
about two inches. The ‘n’ is absolutely necessary
for the scaling to work correctly.

-width ENAMETOOLONG
sets width to the constant width length of the string
given.

-width "int mkfifo"
again, the width is set to the constant width of the
string given.

If a width is not specified for the tag list type, the first time ‘.It’
is invoked, an attempt is made to determine an appropriate width. If the
first argument to ‘.It’ is a callable macro, the default width for that
macro will be used as if the macro name had been supplied as the width.
However, if another item in the list is given with a different callable
macro name, a new and nested list is assumed.

PREDEFINED STRINGS
The following strings are predefined as may be used by preceding with the
troff string interpreting sequence ‘’ where xx is the name of the
defined string or as ‘’ where x is the name of the string. The inter-
preting sequence may be used any where in the text.

String Nroff Troff
<= <= <=
>= >= >=

Rq ’’ ’’
Lq ‘‘ ‘‘
ua ^ ^
aa ’
ga ‘ ‘
q " "
Pi pi pi
Ne != !=
Le <= <=
Ge >= >=
Lt < >
Gt > <
Pm +- +-
If infinity infinity
Na NaN NaN
Ba | |

Note: The string named ‘q’ should be written as ‘’ since it is only
one char.

DIAGNOSTICS
The debugging facilities for -mdoc are limited, but can help detect sub-
tle errors such as the collision of an argument name with an internal
register or macro name. (A what?) A register is an arithmetic storage
class for troff with a one or two character name. All registers internal
to -mdoc for troff and ditroff are two characters and of the form <up-
per_case><lower_case> such as ‘Ar’, <lower_case><upper_case> as ‘aR’ or
<upper or lower letter><digit> as ‘C1’. And adding to the muddle, troff
has its own internal registers all of which are either two lower case
characters or a dot plus a letter or meta-character character. In one of
the introduction examples, it was shown how to prevent the interpretation
of a macro name with the escape sequence ‘’. This is sufficient for the
internal register names also.

If a non-escaped register name is given in the argument list of a request
unpredictable behavior will occur. In general, any time huge portions of
text do not appear where expected in the output, or small strings such as
list tags disappear, chances are there is a misunderstanding about an ar-
gument type in the argument list. Your mother never intended for you to
remember this evil stuff - so here is a way to find out whether or not
your arguments are valid: The ‘.Db’ (debug) macro displays the interpre-
tation of the argument list for most macros. Macros such as the ‘.Pp’
(paragraph) macro do not contain debugging information. All of the
callable macros do, and it is strongly advised whenever in doubt, turn on
the ‘.Db’ macro.

Usage: .Db [on | off]

An example of a portion of text with the debug macro placed above and be-
low an artificially created problem (a flag argument ‘aC’ which should be
‘aC’ in order to work):

.Db on
.Op Fl aC Ar file )
.Db off

The resulting output:

DEBUGGING ON
DEBUG(argv) MACRO: ‘.Op’ Line #: 2
Argc: 1 Argv: ‘Fl’ Length: 2
Space: ‘’ Class: Executable
Argc: 2 Argv: ‘aC’ Length: 2
Space: ‘’ Class: Executable
Argc: 3 Argv: ‘Ar’ Length: 2
Space: ‘’ Class: Executable
Argc: 4 Argv: ‘file’ Length: 4
Space: ‘ ’ Class: String
Argc: 5 Argv: ‘)’ Length: 1
Space: ‘ ’ Class: Closing Punctuation or suffix
MACRO REQUEST: .Op Fl aC Ar file )
DEBUGGING OFF

The first line of information tells the name of the calling macro, here
‘.Op’, and the line number it appears on. If one or more files are in-
volved (especially if text from another file is included) the line number
may be bogus. If there is only one file, it should be accurate. The
second line gives the argument count, the argument (‘Fl’) and its length.
If the length of an argument is two characters, the argument is tested to
see if it is executable (unfortunately, any register which contains a
non-zero value appears executable). The third line gives the space al-
lotted for a class, and the class type. The problem here is the argument
aC should not be executable. The four types of classes are string, exe-
cutable, closing punctuation and opening punctuation. The last line
shows the entire argument list as it was read. In this next example, the
offending ‘aC’ is escaped:

.Db on
.Em An escaped aC
.Db off

DEBUGGING ON
DEBUG(fargv) MACRO: ‘.Em’ Line #: 2
Argc: 1 Argv: ‘An’ Length: 2
Space: ‘ ’ Class: String
Argc: 2 Argv: ‘escaped’ Length: 7
Space: ‘ ’ Class: String
Argc: 3 Argv: ‘aC’ Length: 2
Space: ‘ ’ Class: String
MACRO REQUEST: .Em An escaped &aC
DEBUGGING OFF

The argument ‘aC’ shows up with the same length of 2 as the ‘’ se-
quence produces a zero width, but a register named ‘aC’ was not found
and the type classified as string.

Other diagnostics consist of usage statements and are self explanatory.

GROFF, TROFF AND NROFF
The -mdoc package does not need compatibility mode with groff.

The package inhibits page breaks, and the headers and footers which nor-
mally occur at those breaks with nroff, to make the manual more effi-
cient for viewing on-line. At the moment, groff with -Tascii does eject
the imaginary remainder of the page at end of file. The inhibiting of
the page breaks makes nroff’d files unsuitable for hardcopy. There is a
register named ‘cR’ which can be set to zero in the site dependent style
file /usr/src/share/tmac/doc-nroff to restore the old style behavior.

FILES
/usr/share/tmac/tmac.doc manual macro package
/usr/share/man0/template.doc template for writing a man page