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NAME

       mdoc.samples — tutorial sampler for writing BSD manuals with -mdoc

SYNOPSIS

       man mdoc.samples

DESCRIPTION

       A  tutorial  sampler  for  writing  BSD  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 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 BSD 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.  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.   TITLE MACROS.

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

             5.   MANUAL DOMAIN
                        Addresses.
                        Author name.
                        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.
                        Names.
                        Options.
                        Pathnames.
                        Variables.
                        Cross References.

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

             7.   PAGE STRUCTURE DOMAIN
                        Section Headers.
                        Paragraphs and Line Spacing.
                        Keeps.
                        Displays.
                        Font Modes (Emphasis, Literal, and Symbolic).
                        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
       character  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 arguments 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 special in that their  argument  lists
       are parsed for callable macro names.  This means an argument on the argument list which matches a general
       text  or  manual domain macro name and is determined to be callable will be executed or called when it is
       processed.  In this case, the argument, although the name of a macro, is not preceded by a ‘.’ (dot).  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  reference  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 embedded 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 implement 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 ‘\n’, are handled by replacing the  ‘\’  with  ‘\e’  (e.g.,
       ‘\en’) 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
       /usr/share/misc/mdoc.template.  Several example man pages can also be found in /usr/share/examples/mdoc.

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

       The first items in the template are the macros (.Dd, .Os, .Dt); the document date, the  operating  system
       the  man page or subject source is developed or modified for, and the man page title (in uppercase) 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 omitted.  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, for example, BSD or FreeBSD or
               ATT.  The release should be the standard release  nomenclature  for  the  system  specified,  for
               example,  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 4.3BSD

               or
                     .Os FreeBSD 2.2

               or for a locally produced set

                     .Os CS Department

               The Berkeley default, ‘.Os’ without an argument, has been defined as  BSD  in  the  site-specific
               file  /usr/share/tmac/mdoc/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

INTRODUCTION OF MANUAL AND GENERAL TEXT DOMAINS

   What's in a name...
       The manual domain macro names are derived from  the  day  to  day  informal  language  used  to  describe
       commands,  subroutines  and  related  files.   Slightly different variations of this language are used to
       describe the three different aspects of writing a man page.  First, there is  the  description  of  -mdoc
       macro  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 argument like target as well as an argument to a flag  like
       variable.  The make command line was produced from:

             .Nm make
             .Op Fl eiknqrstv
             .Op Fl D Ar variable
             .Op Fl d Ar flags
             .Op Fl f Ar makefile
             .Op Fl I Ar directory
             .Op Fl j Ar max_jobs
             .Op Ar variable=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  punctuation,  provided  each  punctuation character is
       separated by a leading space.  If a 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 distinguishing 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 presented with a string containing a member of the  mathematical,
       logical or quotation set:

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

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

MANUAL DOMAIN

   Address Macro
       The address macro identifies an address construct of the form addr1[,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.

   Author Name
       The  ‘.An’  macro  is used to specify the name of the author of the item being documented, or the name of
       the author of the actual manual page.  Any remaining arguments after the name information are assumed  to
       be punctuation.

             Usage: .An author_name [.,:;()[]?!]
                     .An Joe Author        Joe Author
                     .An Joe Author ,      Joe Author,
                     .An Joe Author Aq nobody@FreeBSD.ORG
                                           Joe Author <nobody@FreeBSD.ORG>
                     .An Joe Author ) ) ,  Joe Author)),

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

   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, ‘Ar’ 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 device interface in a section four
       manual.  This macro accepts quoted arguments (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 argument.  Traditionally flags are marked by  the  preceding  dash,  some
       commands  or subsets of commands do not use them.  Command modifiers may also be specified in conjunction
       with interactive commands such as editor commands.  See “Flags”.

   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) outside 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 declaration 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 line 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: .Ic 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.

   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 pathnames or filenames.

             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&T UNIX
                     .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
                     .Bx 4.3 .    4.3BSD.

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

   FreeBSD Macro
             Usage: .Fx Version.release ... [ .,:;()[]?! ]
                     .Fx 2.2 .    FreeBSD 2.2.

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

   UNIX Macro
             Usage: .Ux ... [.,:;()[]?!]
                     .Ux          Unix

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

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

       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.

   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”

   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 predictably at the moment either.)  The purpose is to allow trade
       names to be pretty printed in troff/ditroff output.

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

             Usage: .Rv [-std function]

       ‘.Rv -std atexit’ will generate the following text:

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

       The -std option is valid only for manual page sections 2 and 3.

   Trade Names (or Acronyms and Type Names)
       The trade name macro is generally a small caps macro for all uppercase 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 \en Ar count No \en
             .Xc
             .Sm on

       Produces

             Ioperation\ncount\n

       Another one:

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

       Produces

             S/old_pattern/new_pattern/[g]

       Another example of ‘.Xo’ and using enclosure macros: Test the value of a 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  often, 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  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 possible, 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’ configuration device usage macro.  Several  other
                     macros may be necessary to produce the synopsis line as shown below:

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

       The following macros were used:

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

       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, followed by a lexical list of options and respective explanations.  To create
               such a list, the ‘.Bl’ begin-list, ‘.It’ list-item and ‘.El’ end-list macros are used (see “Lists
               and Columns” below).

       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.  Cross references in the “SEE ALSO” section should be sorted  by  section  number,
                 and then placed in alphabetical order and comma separated.  For example:

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

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

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

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

       .Sh AUTHORS
                 Credits, 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 STRUCTURE DOMAIN

   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 ‘.Bk’ 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  prevent  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’ example macro has been used
              throughout this file.  It allows the indent (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  filename following the -file flag is read and displayed.  Literal mode is asserted
                         and tabs are set at 8 constant  width  character  intervals,  however  any  troff/-mdoc
                         commands in file will be processed.
       -offset string    If -offset is specified with one of the following strings, the string is interpreted to
                         indicate the level of indentation for the forthcoming block of text:

                         left        Align block on the current left margin, this is the default mode of ‘.Bd’.
                         center      Supposedly  center the block.  At this time unfortunately, the block merely
                                     gets left aligned about an imaginary center margin.
                         indent      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.

   Font Modes
       There are five macros for changing the appearance of the manual page text:

       .Em    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.

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

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

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

       .Sy    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.

       .Bf    Begin font mode.  The ‘.Bf’ font mode must be ended with the  ‘.Ef’  macro.   Font  modes  may  be
              nested within other font modes.  ‘.Bf’ has the following syntax:

                    .Bf font-mode

              The font-mode must be one of the following three types: ‘.Bf’.

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

       .Ef    End font mode.

   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 allowed 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 present 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:
                    Bullet one goes here.
                    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 ‘Fl 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 similar to inset lists except callable
             macros are ignored.

             Hang Hanged labels are a matter of taste.

             Ohang Overhanging labels are nice when space is constrained.

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

       Here is the source text which produced the above example:

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

       Here is a hanged list with two items:

             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 process to pages not loaded in core.
             UID     numerical user-id of process owner
             PPID    numerical ID of parent of process process priority (nonpositive  when  in  noninterruptible
                     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
             (nonpositive when in noninterruptible 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  ‘\*(xx’  where  xx  is  the  name  of the defined string or as ‘\*x’ where x is the name of the
       string.  The interpreting sequence may be used any where in the text.

             String     Nroff     Troff
             <=         <=        ≤
             >=         >=        ≥
             Rq         ''        ”
             Lq         ``        “
             ua         ^         ↑
             aa         '         ´
             ga         `         `
             q          "         "
             Pi         pi        π
             Ne         !=        ≠
             Le         <=        ≤
             Ge         >=        ≥
             Lt         <         >
             Gt         >         <
             Pm         +-        ±
             If         infinity  ∞
             Na         NaN       NaN
             Ba         |         |

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

DIAGNOSTICS

       The debugging facilities for -mdoc are limited, but can help detect subtle 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   <upper_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 lowercase characters or a dot plus a
       letter or metacharacter 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 nonescaped 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  argument  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 interpretation  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 below 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 involved (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 nonzero value
       appears executable).  The third line gives the space allotted 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,
       executable, 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 ‘\&’ sequence 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 normally occur at those breaks with
       nroff, to make the manual more efficient 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/doc.tmac      manual macro package
       /usr/share/misc/mdoc.template
                                     template for writing a man page
       /usr/share/examples/mdoc/*    several example man pages

BUGS

       Undesirable hyphenation on the dash of a flag argument is not yet resolved, and causes occasional mishaps
       in the “DESCRIPTION” section.  (line break on the hyphen).

       Predefined strings are not declared in documentation.

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

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

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

       The method used to prevent header and footer page breaks (other than the initial header and footer)  when
       using  nroff occasionally places an unsightly partially filled line (blank) at the would be bottom of the
       page.

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

SEE ALSO

       man(1), troff(1), groff_mdoc(7), mdoc(7)

COLOPHON

       This page is part of release 4.15 of  the  Linux  man-pages  project.   A  description  of  the  project,
       information   about   reporting   bugs,   and   the  latest  version  of  this  page,  can  be  found  at
       https://www.kernel.org/doc/man-pages/.

Debian                                          December 30, 1993                                MDOC.SAMPLES(7)