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version 1.65, 2009/10/19 11:02:23 version 1.201, 2011/08/17 22:20:14
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 .\"     $Id$  .\"     $Id$
 .\"  .\"
 .\" Copyright (c) 2009 Kristaps Dzonsons <kristaps@kth.se>  .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
   .\" Copyright (c) 2010 Ingo Schwarze <schwarze@openbsd.org>
 .\"  .\"
 .\" Permission to use, copy, modify, and distribute this software for any  .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above  .\" purpose with or without fee is hereby granted, provided that the above
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 .Dd $Mdocdate$  .Dd $Mdocdate$
 .Dt MDOC 7  .Dt MDOC 7
 .Os  .Os
 .  
 .  
 .Sh NAME  .Sh NAME
 .Nm mdoc  .Nm mdoc
 .Nd mdoc language reference  .Nd mdoc language reference
 .  
 .  
 .Sh DESCRIPTION  .Sh DESCRIPTION
 The  The
 .Nm mdoc  .Nm mdoc
 language is used to format  language is used to format
 .Bx  .Bx
 .Ux  .Ux
 manuals.  In this reference document, we describe its syntax, structure,  manuals.
 and usage.  Our reference implementation is  This reference document describes its syntax, structure, and
 .Xr mandoc 1 .  usage.
 The  The reference implementation for
   .Nm
   formatting is
   .Xr mandoc 1 ;
   the
 .Sx COMPATIBILITY  .Sx COMPATIBILITY
 section describes compatibility with  section describes compatibility with other implementations.
 .Xr groff 1 .  
 .  
 .Pp  .Pp
 An  An
 .Nm  .Nm
 document follows simple rules:  lines beginning with the control  document follows simple rules: lines beginning with the control
 character  character
 .Sq \.  .Sq \&.
 are parsed for macros.  Other lines are interpreted within the scope of  are parsed for macros.
 prior macros:  Lines not beginning with the control character are
   interpreted within the scope of prior macros:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Sh Macro lines change control state.  \&.Sh Macro lines change control state.
 Other lines are interpreted within the current state.  Text lines are interpreted within the current state.
 .Ed  .Ed
 .  
 .  
 .Sh LANGUAGE SYNTAX  .Sh LANGUAGE SYNTAX
 .Nm  .Nm
 documents may contain only graphable 7-bit ASCII characters, the space  documents may contain only graphable 7-bit ASCII characters, the space
 character, and, in certain circumstances, the tab character.  All  character, and, in certain circumstances, the tab character.
 manuals must have  The back-space character
 .Ux  .Sq \e
 line terminators.  indicates the start of an escape sequence for
 .  .Sx Comments ,
 .  .Sx Predefined Strings ,
   and
   .Sx Special Characters .
 .Ss Comments  .Ss Comments
 Text following a  Text following an escaped double-quote
 .Sq \e" ,  .Sq \e\*q ,
 whether in a macro or free-form text line, is ignored to the end of  whether in a macro or text line, is ignored to the end of
 line.  A macro line with only a control character and comment escape,  line.
 .Sq \&.\e" ,  A macro line beginning with a control character and comment escape
 is also ignored.  Macro lines with only a control charater and optionally  .Sq \&.\e\*q
 whitespace are stripped from input.  is also ignored.
 .  Furthermore,
 .  macro lines with only a control character and optional trailing
 .Ss Reserved Characters  whitespace are
 Within a macro line, the following characters are reserved:  stripped from input.
 .Pp  .Pp
 .Bl -tag -width Ds -offset indent -compact  Examples:
 .It \&.  .Bd -literal -offset indent -compact
 .Pq period  \&.\e\*q This is a comment line.
 .It \&,  \&.\e\*q The next line is ignored:
 .Pq comma  \&.
 .It \&:  \&.Em Emphasis \e\*q This is also a comment.
 .Pq colon  .Ed
 .It \&;  
 .Pq semicolon  
 .It \&(  
 .Pq left-parenthesis  
 .It \&)  
 .Pq right-parenthesis  
 .It \&[  
 .Pq left-bracket  
 .It \&]  
 .Pq right-bracket  
 .It \&?  
 .Pq question  
 .It \&!  
 .Pq exclamation  
 .It \&|  
 .Pq vertical bar  
 .El  
 .  
 .Pp  
 Use of reserved characters is described in  
 .Sx MACRO SYNTAX .  
 For general use in macro lines, these characters must either be escaped  
 with a non-breaking space  
 .Pq Sq \e&  
 or, if applicable, an appropriate escape sequence used.  
 .  
 .  
 .Ss Special Characters  .Ss Special Characters
 Special characters may occur in both macro and free-form lines.  Special characters are used to encode special glyphs and are rendered
   differently across output media.
   They may occur in both macro and text lines.
 Sequences begin with the escape character  Sequences begin with the escape character
 .Sq \e  .Sq \e
 followed by either an open-parenthesis  followed by either an open-parenthesis
Line 118  for two-character sequences; an open-bracket
Line 93  for two-character sequences; an open-bracket
 .Sq \&[  .Sq \&[
 for n-character sequences (terminated at a close-bracket  for n-character sequences (terminated at a close-bracket
 .Sq \&] ) ;  .Sq \&] ) ;
 or a single one-character sequence.  See  or a single one character sequence.
   .Pp
   Examples:
   .Bl -tag -width Ds -offset indent -compact
   .It \e(em
   em dash
   .It \ee
   backslash
   .El
   .Pp
   See
 .Xr mandoc_char 7  .Xr mandoc_char 7
 for a complete list.  Examples include  for a complete list.
 .Sq \e(em  
 .Pq em-dash  
 and  
 .Sq \ee  
 .Pq back-slash .  
 .  
 .  
 .Ss Text Decoration  .Ss Text Decoration
 Terms may be text-decorated using the  Terms may be text-decorated using the
 .Sq \ef  .Sq \ef
 escape followed by an indicator: B (bold), I, (italic), or P and R  escape followed by an indicator: B (bold), I (italic), R (regular), or P
 (Roman, or reset).  This form is not recommended for  (revert to previous mode).
   A numerical representation 3, 2, or 1 (bold, italic, and regular,
   respectively) may be used instead.
   If a macro opens a font scope after calling
   .Sq \ef ,
   such as with
   .Sx \&Bf ,
   the
   .Sq \ef
   mode will be restored upon exiting the
   .Sx \&Bf
   scope.
   .Pp
   Examples:
   .Bl -tag -width Ds -offset indent -compact
   .It \efBbold\efR
   write in bold, then switch to regular
   .It \efIitalic\efP
   write in italic, then return to previous
   .El
   .Pp
   Text decoration is
   .Em not
   recommended for
 .Nm ,  .Nm ,
 which encourages semantic, not presentation, annotation.  which encourages semantic annotation.
 .  
 .  
 .Ss Predefined Strings  .Ss Predefined Strings
 Historically,  Predefined strings, like
 .Xr groff 1  
 also defined a set of package-specific  
 .Dq predefined strings ,  
 which, like  
 .Sx Special Characters ,  .Sx Special Characters ,
 demark special output characters and strings by way of input codes.  mark special output glyphs.
 Predefined strings are escaped with the slash-asterisk,  Predefined strings are escaped with the slash-asterisk,
 .Sq \e* :  .Sq \e* :
 single-character  single-character
Line 153  two-character
Line 148  two-character
 .Sq \e*(XX ,  .Sq \e*(XX ,
 and N-character  and N-character
 .Sq \e*[N] .  .Sq \e*[N] .
 See  .Pp
 .Xr mandoc_char 7  Examples:
 for a complete list.  Examples include  .Bl -tag -width Ds -offset indent -compact
 .Sq \e*(Am  .It \e*(Am
 .Pq ampersand  ampersand
 and  .It \e*(Ba
 .Sq \e*(Ba  vertical bar
 .Pq vertical bar .  .El
 .  .Pp
 .  These strings are set using
   .Xr roff 7 ,
   although
   .Nm
   consists of several pre-set escapes listed in
   .Xr mandoc_char 7 .
 .Ss Whitespace  .Ss Whitespace
 In non-literal free-form lines, consecutive blocks of whitespace are  Whitespace consists of the space character.
 pruned from input and added later in the output filter, if applicable:  In text lines, whitespace is preserved within a line.
 .Bd -literal -offset indent  In macro lines, whitespace delimits arguments and is discarded.
 These     spaces   are    pruned       from    input.  
 \&.Bd \-literal  
 These         are              not.  
 \&.Ed  
 .Ed  
 .  
 .Pp  .Pp
 In macro lines, whitespace delimits arguments and is discarded.  If  Unescaped trailing spaces are stripped from text line input unless in a
 arguments are quoted, whitespace within the quotes is retained.  literal context.
 .  In general, trailing whitespace on any input line is discouraged for
   reasons of portability.
   In the rare case that a blank character is needed at the end of an
   input line, it may be forced by
   .Sq \e\ \e& .
 .Pp  .Pp
 Blank lines are only permitted within literal contexts, as are lines  Blank text lines, which may include whitespace, are only permitted
 containing only whitespace.  Tab characters are only acceptable when  within literal contexts.
 delimiting  If the first character of a text line is a space, that line is printed
 .Sq \&Bl \-column  with a leading newline.
 or when in a literal context.  
 .  
 .  
 .Ss Quotation  .Ss Quotation
 Macro arguments may be quoted with a double-quote to group  Macro arguments may be quoted with double-quotes; in this case,
 space-delimited terms or to retain blocks of whitespace.  A quoted  whitespace within the quotes is retained as part of the argument.
 argument begins with a double-quote preceded by whitespace.  The next  For example,
 double-quote not pair-wise adjacent to another double-quote terminates  
 the literal, regardless of surrounding whitespace.  
 .  
 .Pp  .Pp
 This produces tokens  .D1 Pf \. \&Fn strlen "\(dqconst char *s\(dq"
 .Sq a" ,  
 .Sq b c ,  
 .Sq de ,  
 and  
 .Sq fg" .  
 Note that any quoted term, be it argument or macro, is indiscriminately  
 considered literal text.  Thus, the following produces  
 .Sq \&Em a :  
 .Bd -literal -offset indent  
 \&.Em "Em a"  
 .Ed  
 .  
 .Pp  .Pp
 In free-form mode, quotes are regarded as opaque text.  renders as
 .  .Sq Fn strlen "const char *s" ,
 .Ss Dates  while
 TODO.  .Pp
 .  .D1 Pf \. \&Fn strlen "const char *s"
 .Ss Scaling Widths  .Pp
 Many macros support scaled widths for their arguments, such as  would produce
 stipulating a two-inch list indentation with the following:  .Sq Fn strlen const char *s .
   .Pp
   A quoted argument begins with a double-quote preceded by whitespace.
   The next double-quote not pairwise adjacent to another double-quote
   terminates the literal, regardless of surrounding whitespace.
   .Pp
   In unquoted arguments, space characters can alternatively be included
   by preceding them with a backslash
   .Pq Sq \e\~ ,
   but quoting is usually better for clarity.
   .Pp
   Note that any quoted text, even if it would cause a macro invocation
   when unquoted, is considered literal text.
   Thus, the following produces
   .Sq Op "Fl a" :
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Bl -tag -width 2i  \&.Op "Fl a"
 .Ed  .Ed
 .  
 .Pp  .Pp
 The syntax for scaled widths is  In text lines, quotes are regarded as opaque text.
   .Ss Scaling Widths
   Many macros support scaled widths for their arguments.
   The syntax for a scaled width is
 .Sq Li [+-]?[0-9]*.[0-9]*[:unit:] ,  .Sq Li [+-]?[0-9]*.[0-9]*[:unit:] ,
 where a decimal must be preceded or proceeded by at least one digit.  where a decimal must be preceded or proceeded by at least one digit.
 Negative numbers, while accepted, are truncated to zero.  The following  Negative numbers, while accepted, are truncated to zero.
 scaling units are accepted:  
 .Pp  .Pp
   The following scaling units are accepted:
   .Pp
 .Bl -tag -width Ds -offset indent -compact  .Bl -tag -width Ds -offset indent -compact
 .It c  .It c
 centimetre  centimetre
Line 262  Using anything other than
Line 259  Using anything other than
 .Sq u ,  .Sq u ,
 or  or
 .Sq v  .Sq v
 is necessarily non-portable across output media.  See  is necessarily non-portable across output media.
   See
 .Sx COMPATIBILITY .  .Sx COMPATIBILITY .
 .  .Pp
 .  Examples:
   .Bl -tag -width Ds -offset indent -compact
   .It \&.Bl -tag -width 2i
   two-inch tagged list indentation
   .Pq see Sx \&Bl
   .It \&.sp 2v
   two vertical spaces
   .Pq see Sx \&sp
   .El
   .Ss Sentence Spacing
   Sentences should terminate at the end of an input line.
   By doing this, a formatter will be able to apply the proper amount of
   spacing after the end of sentence (unescaped) period, exclamation mark,
   or question mark followed by zero or more non-sentence closing
   delimiters
   .Po
   .Sq \&) ,
   .Sq \&] ,
   .Sq \&' ,
   .Sq \&"
   .Pc .
   .Pp
   The proper spacing is also intelligently preserved if a sentence ends at
   the boundary of a macro line.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   Do not end sentences mid-line like this.  Instead,
   end a sentence like this.
   A macro would end like this:
   \&.Xr mandoc 1 \&.
   .Ed
 .Sh MANUAL STRUCTURE  .Sh MANUAL STRUCTURE
 Each  A well-formed
 .Nm  .Nm
 document must begin with a document prologue, containing, in order,  document consists of a document prologue followed by one or more
   sections.
   .Pp
   The prologue, which consists of the
 .Sx \&Dd ,  .Sx \&Dd ,
 .Sx \&Dt ,  .Sx \&Dt ,
 and  and
 .Sx \&Os ,  .Sx \&Os
 then the NAME section containing at least one  macros in that order, is required for every document.
   .Pp
   The first section (sections are denoted by
   .Sx \&Sh )
   must be the NAME section, consisting of at least one
 .Sx \&Nm  .Sx \&Nm
 followed by  followed by
 .Sx \&Nd :  .Sx \&Nd .
   .Pp
   Following that, convention dictates specifying at least the
   .Em SYNOPSIS
   and
   .Em DESCRIPTION
   sections, although this varies between manual sections.
   .Pp
   The following is a well-formed skeleton
   .Nm
   file for a utility
   .Qq progname :
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Dd $\&Mdocdate$  \&.Dd $\&Mdocdate$
 \&.Dt mdoc 7  \&.Dt PROGNAME section
 \&.Os  \&.Os
 \&.  
 \&.Sh NAME  \&.Sh NAME
 \&.Nm foo  \&.Nm progname
 \&.Nd a description goes here  \&.Nd one line about what it does
 \&.\e\*q The next is for sections 2 & 3 only.  
 \&.\e\*q .Sh LIBRARY  \&.\e\*q .Sh LIBRARY
 \&.  \&.\e\*q For sections 2, 3, & 9 only.
   \&.\e\*q Not used in OpenBSD.
 \&.Sh SYNOPSIS  \&.Sh SYNOPSIS
 \&.Nm foo  \&.Nm progname
 \&.Op Fl options  \&.Op Fl options
 \&.Ar  \&.Ar
 \&.  
 \&.Sh DESCRIPTION  \&.Sh DESCRIPTION
 The  The
 \&.Nm  \&.Nm
 utility processes files ...  utility processes files ...
 \&.\e\*q .Sh IMPLEMENTATION NOTES  \&.\e\*q .Sh IMPLEMENTATION NOTES
 \&.\e\*q The next is for sections 1 & 8 only.  \&.\e\*q Not used in OpenBSD.
 \&.\e\*q .Sh EXIT STATUS  
 \&.\e\*q The next is for sections 2, 3, & 9 only.  
 \&.\e\*q .Sh RETURN VALUES  \&.\e\*q .Sh RETURN VALUES
 \&.\e\*q The next is for sections 1, 6, 7, & 8 only.  \&.\e\*q For sections 2, 3, & 9 only.
 \&.\e\*q .Sh ENVIRONMENT  \&.\e\*q .Sh ENVIRONMENT
   \&.\e\*q For sections 1, 6, 7, & 8 only.
 \&.\e\*q .Sh FILES  \&.\e\*q .Sh FILES
   \&.\e\*q .Sh EXIT STATUS
   \&.\e\*q For sections 1, 6, & 8 only.
 \&.\e\*q .Sh EXAMPLES  \&.\e\*q .Sh EXAMPLES
 \&.\e\*q The next is for sections 1, 4, 6, 7, & 8 only.  
 \&.\e\*q .Sh DIAGNOSTICS  \&.\e\*q .Sh DIAGNOSTICS
 \&.\e\*q The next is for sections 2, 3, & 9 only.  \&.\e\*q For sections 1, 4, 6, 7, & 8 only.
 \&.\e\*q .Sh ERRORS  \&.\e\*q .Sh ERRORS
   \&.\e\*q For sections 2, 3, & 9 only.
 \&.\e\*q .Sh SEE ALSO  \&.\e\*q .Sh SEE ALSO
 \&.\e\*q .Xr foobar 1  \&.\e\*q .Xr foobar 1
 \&.\e\*q .Sh STANDARDS  \&.\e\*q .Sh STANDARDS
Line 319  utility processes files ...
Line 365  utility processes files ...
 \&.\e\*q .Sh CAVEATS  \&.\e\*q .Sh CAVEATS
 \&.\e\*q .Sh BUGS  \&.\e\*q .Sh BUGS
 \&.\e\*q .Sh SECURITY CONSIDERATIONS  \&.\e\*q .Sh SECURITY CONSIDERATIONS
   \&.\e\*q Not used in OpenBSD.
 .Ed  .Ed
 .  
 .Pp  .Pp
 Subsequent SYNOPSIS and DESCRIPTION sections are strongly encouraged,  The sections in an
 but non-compulsory.  .Nm
 .  document are conventionally ordered as they appear above.
 .  Sections should be composed as follows:
   .Bl -ohang -offset Ds
   .It Em NAME
   The name(s) and a one line description of the documented material.
   The syntax for this as follows:
   .Bd -literal -offset indent
   \&.Nm name0 ,
   \&.Nm name1 ,
   \&.Nm name2
   \&.Nd a one line description
   .Ed
   .Pp
   Multiple
   .Sq \&Nm
   names should be separated by commas.
   .Pp
   The
   .Sx \&Nm
   macro(s) must precede the
   .Sx \&Nd
   macro.
   .Pp
   See
   .Sx \&Nm
   and
   .Sx \&Nd .
   .It Em LIBRARY
   The name of the library containing the documented material, which is
   assumed to be a function in a section 2, 3, or 9 manual.
   The syntax for this is as follows:
   .Bd -literal -offset indent
   \&.Lb libarm
   .Ed
   .Pp
   See
   .Sx \&Lb .
   .It Em SYNOPSIS
   Documents the utility invocation syntax, function call syntax, or device
   configuration.
   .Pp
   For the first, utilities (sections 1, 6, and 8), this is
   generally structured as follows:
   .Bd -literal -offset indent
   \&.Nm bar
   \&.Op Fl v
   \&.Op Fl o Ar file
   \&.Op Ar
   \&.Nm foo
   \&.Op Fl v
   \&.Op Fl o Ar file
   \&.Op Ar
   .Ed
   .Pp
   Commands should be ordered alphabetically.
   .Pp
   For the second, function calls (sections 2, 3, 9):
   .Bd -literal -offset indent
   \&.In header.h
   \&.Vt extern const char *global;
   \&.Ft "char *"
   \&.Fn foo "const char *src"
   \&.Ft "char *"
   \&.Fn bar "const char *src"
   .Ed
   .Pp
   Ordering of
   .Sx \&In ,
   .Sx \&Vt ,
   .Sx \&Fn ,
   and
   .Sx \&Fo
   macros should follow C header-file conventions.
   .Pp
   And for the third, configurations (section 4):
   .Bd -literal -offset indent
   \&.Cd \*qit* at isa? port 0x2e\*q
   \&.Cd \*qit* at isa? port 0x4e\*q
   .Ed
   .Pp
   Manuals not in these sections generally don't need a
   .Em SYNOPSIS .
   .Pp
   Some macros are displayed differently in the
   .Em SYNOPSIS
   section, particularly
   .Sx \&Nm ,
   .Sx \&Cd ,
   .Sx \&Fd ,
   .Sx \&Fn ,
   .Sx \&Fo ,
   .Sx \&In ,
   .Sx \&Vt ,
   and
   .Sx \&Ft .
   All of these macros are output on their own line.
   If two such dissimilar macros are pairwise invoked (except for
   .Sx \&Ft
   before
   .Sx \&Fo
   or
   .Sx \&Fn ) ,
   they are separated by a vertical space, unless in the case of
   .Sx \&Fo ,
   .Sx \&Fn ,
   and
   .Sx \&Ft ,
   which are always separated by vertical space.
   .Pp
   When text and macros following an
   .Sx \&Nm
   macro starting an input line span multiple output lines,
   all output lines but the first will be indented to align
   with the text immediately following the
   .Sx \&Nm
   macro, up to the next
   .Sx \&Nm ,
   .Sx \&Sh ,
   or
   .Sx \&Ss
   macro or the end of an enclosing block, whichever comes first.
   .It Em DESCRIPTION
   This begins with an expansion of the brief, one line description in
   .Em NAME :
   .Bd -literal -offset indent
   The
   \&.Nm
   utility does this, that, and the other.
   .Ed
   .Pp
   It usually follows with a breakdown of the options (if documenting a
   command), such as:
   .Bd -literal -offset indent
   The arguments are as follows:
   \&.Bl \-tag \-width Ds
   \&.It Fl v
   Print verbose information.
   \&.El
   .Ed
   .Pp
   Manuals not documenting a command won't include the above fragment.
   .Pp
   Since the
   .Em DESCRIPTION
   section usually contains most of the text of a manual, longer manuals
   often use the
   .Sx \&Ss
   macro to form subsections.
   In very long manuals, the
   .Em DESCRIPTION
   may be split into multiple sections, each started by an
   .Sx \&Sh
   macro followed by a non-standard section name, and each having
   several subsections, like in the present
   .Nm
   manual.
   .It Em IMPLEMENTATION NOTES
   Implementation-specific notes should be kept here.
   This is useful when implementing standard functions that may have side
   effects or notable algorithmic implications.
   .It Em RETURN VALUES
   This section documents the
   return values of functions in sections 2, 3, and 9.
   .Pp
   See
   .Sx \&Rv .
   .It Em ENVIRONMENT
   Lists the environment variables used by the utility,
   and explains the syntax and semantics of their values.
   The
   .Xr environ 7
   manual provides examples of typical content and formatting.
   .Pp
   See
   .Sx \&Ev .
   .It Em FILES
   Documents files used.
   It's helpful to document both the file name and a short description of how
   the file is used (created, modified, etc.).
   .Pp
   See
   .Sx \&Pa .
   .It Em EXIT STATUS
   This section documents the
   command exit status for section 1, 6, and 8 utilities.
   Historically, this information was described in
   .Em DIAGNOSTICS ,
   a practise that is now discouraged.
   .Pp
   See
   .Sx \&Ex .
   .It Em EXAMPLES
   Example usages.
   This often contains snippets of well-formed, well-tested invocations.
   Make sure that examples work properly!
   .It Em DIAGNOSTICS
   Documents error conditions.
   This is most useful in section 4 manuals.
   Historically, this section was used in place of
   .Em EXIT STATUS
   for manuals in sections 1, 6, and 8; however, this practise is
   discouraged.
   .Pp
   See
   .Sx \&Bl
   .Fl diag .
   .It Em ERRORS
   Documents error handling in sections 2, 3, and 9.
   .Pp
   See
   .Sx \&Er .
   .It Em SEE ALSO
   References other manuals with related topics.
   This section should exist for most manuals.
   Cross-references should conventionally be ordered first by section, then
   alphabetically.
   .Pp
   References to other documentation concerning the topic of the manual page,
   for example authoritative books or journal articles, may also be
   provided in this section.
   .Pp
   See
   .Sx \&Rs
   and
   .Sx \&Xr .
   .It Em STANDARDS
   References any standards implemented or used.
   If not adhering to any standards, the
   .Em HISTORY
   section should be used instead.
   .Pp
   See
   .Sx \&St .
   .It Em HISTORY
   A brief history of the subject, including where it was first implemented,
   and when it was ported to or reimplemented for the operating system at hand.
   .It Em AUTHORS
   Credits to the person or persons who wrote the code and/or documentation.
   Authors should generally be noted by both name and email address.
   .Pp
   See
   .Sx \&An .
   .It Em CAVEATS
   Common misuses and misunderstandings should be explained
   in this section.
   .It Em BUGS
   Known bugs, limitations, and work-arounds should be described
   in this section.
   .It Em SECURITY CONSIDERATIONS
   Documents any security precautions that operators should consider.
   .El
 .Sh MACRO SYNTAX  .Sh MACRO SYNTAX
 Macros are one to three three characters in length and begin with a  Macros are one to three three characters in length and begin with a
 control character ,  control character,
 .Sq \&. ,  .Sq \&. ,
 at the beginning of the line.  An arbitrary amount of whitespace may  at the beginning of the line.
 sit between the control character and the macro name.  Thus, the  An arbitrary amount of whitespace may sit between the control character
 following are equivalent:  and the macro name.
   Thus, the following are equivalent:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Pp  \&.Pp
 \&.\ \ \ \&Pp  \&.\ \ \ \&Pp
 .Ed  .Ed
 .  
 .Pp  .Pp
 The syntax of a macro depends on its classification.  In this section,  The syntax of a macro depends on its classification.
   In this section,
 .Sq \-arg  .Sq \-arg
 refers to macro arguments, which may be followed by zero or more  refers to macro arguments, which may be followed by zero or more
 .Sq parm  .Sq parm
Line 348  parameters;
Line 644  parameters;
 opens the scope of a macro; and if specified,  opens the scope of a macro; and if specified,
 .Sq \&Yc  .Sq \&Yc
 closes it out.  closes it out.
 .  
 .Pp  .Pp
 The  The
 .Em Callable  .Em Callable
 column indicates that the macro may be called subsequent to the initial  column indicates that the macro may also be called by passing its name
 line-macro.  If a macro is not callable, then its invocation after the  as an argument to another macro.
 initial line macro is interpreted as opaque text, such that  For example,
   .Sq \&.Op \&Fl O \&Ar file
   produces
   .Sq Op Fl O Ar file .
   To prevent a macro call and render the macro name literally,
   escape it by prepending a zero-width space,
   .Sq \e& .
   For example,
   .Sq \&Op \e&Fl O
   produces
   .Sq Op \&Fl O .
   If a macro is not callable but its name appears as an argument
   to another macro, it is interpreted as opaque text.
   For example,
 .Sq \&.Fl \&Sh  .Sq \&.Fl \&Sh
 produces  produces
 .Sq Fl \&Sh .  .Sq Fl \&Sh .
 .  
 .Pp  .Pp
 The  The
 .Em Parsable  .Em Parsed
 column indicates whether the macro may be followed by further  column indicates whether the macro may call other macros by receiving
 (ostensibly callable) macros.  If a macro is not parsable, subsequent  their names as arguments.
 macro invocations on the line will be interpreted as opaque text.  If a macro is not parsed but the name of another macro appears
 .  as an argument, it is interpreted as opaque text.
 .Pp  .Pp
 The  The
 .Em Scope  .Em Scope
 column, if applicable, describes closure rules.  column, if applicable, describes closure rules.
 .  
 .  
 .Ss Block full-explicit  .Ss Block full-explicit
 Multi-line scope closed by an explicit closing macro.  All macros  Multi-line scope closed by an explicit closing macro.
 contains bodies; only  All macros contains bodies; only
 .Sx \&Bf  .Sx \&Bf
 contains a head.  and
   .Pq optionally
   .Sx \&Bl
   contain a head.
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB  \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
 \(lBbody...\(rB  \(lBbody...\(rB
 \&.Yc  \&.Yc
 .Ed  .Ed
 .  
 .Pp  .Pp
 .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsableX" "closed by XXX"  .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsedX" "closed by XXX"
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
 .It Sx \&Bd  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ed  .It Sx \&Bd  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ed
 .It Sx \&Bf  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ef  .It Sx \&Bf  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ef
 .It Sx \&Bk  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ek  .It Sx \&Bk  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ek
Line 395  contains a head.
Line 702  contains a head.
 .It Sx \&Ek  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bk  .It Sx \&Ek  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bk
 .It Sx \&El  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bl  .It Sx \&El  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bl
 .El  .El
 .  
 .  
 .Ss Block full-implicit  .Ss Block full-implicit
 Multi-line scope closed by end-of-file or implicitly by another macro.  Multi-line scope closed by end-of-file or implicitly by another macro.
 All macros have bodies; some  All macros have bodies; some
Line 409  All macros have bodies; some
Line 714  All macros have bodies; some
 .Pc  .Pc
 don't have heads; only one  don't have heads; only one
 .Po  .Po
 .Sx \&It Fl column  .Sx \&It
 .Pc  in
   .Sx \&Bl Fl column
   .Pc
 has multiple heads.  has multiple heads.
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead... \(lBTa head...\(rB\(rB  \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead... \(lBTa head...\(rB\(rB
 \(lBbody...\(rB  \(lBbody...\(rB
 .Ed  .Ed
 .  
 .Pp  .Pp
 .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsableX" "closed by XXXXXXXXXXX"  .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsedX" "closed by XXXXXXXXXXX"
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
 .It Sx \&It  Ta    \&No     Ta    Yes      Ta    closed by Sx \&It , Sx \&El  .It Sx \&It Ta \&No Ta Yes  Ta closed by Sx \&It , Sx \&El
 .It Sx \&Nd  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Sh  .It Sx \&Nd Ta \&No Ta \&No Ta closed by Sx \&Sh
 .It Sx \&Sh  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Sh  .It Sx \&Nm Ta \&No Ta Yes  Ta closed by Sx \&Nm , Sx \&Sh , Sx \&Ss
 .It Sx \&Ss  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Sh , Sx \&Ss  .It Sx \&Sh Ta \&No Ta Yes  Ta closed by Sx \&Sh
   .It Sx \&Ss Ta \&No Ta Yes  Ta closed by Sx \&Sh , Sx \&Ss
 .El  .El
 .  .Pp
 .  Note that the
   .Sx \&Nm
   macro is a
   .Sx Block full-implicit
   macro only when invoked as the first macro
   in a
   .Em SYNOPSIS
   section line, else it is
   .Sx In-line .
 .Ss Block partial-explicit  .Ss Block partial-explicit
 Like block full-explicit, but also with single-line scope.  Each  Like block full-explicit, but also with single-line scope.
 has at least a body and, in limited circumstances, a head  Each has at least a body and, in limited circumstances, a head
 .Po  .Po
 .Sx \&Fo ,  .Sx \&Fo ,
 .Sx \&Eo  .Sx \&Eo
Line 444  and/or tail
Line 759  and/or tail
 \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB \  \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB \
 \(lBbody...\(rB \&Yc \(lBtail...\(rB  \(lBbody...\(rB \&Yc \(lBtail...\(rB
 .Ed  .Ed
 .  
 .Pp  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" "closed by XXXX" -compact -offset indent  .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXX" -compact -offset indent
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
 .It Sx \&Ac  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Ao  .It Sx \&Ac  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Ao
 .It Sx \&Ao  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Ac  .It Sx \&Ao  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Ac
 .It Sx \&Bc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Bo  .It Sx \&Bc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Bo
Line 473  and/or tail
Line 787  and/or tail
 .It Sx \&Xc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Xo  .It Sx \&Xc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Xo
 .It Sx \&Xo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Xc  .It Sx \&Xo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Xc
 .El  .El
 .  
 .  
 .Ss Block partial-implicit  .Ss Block partial-implicit
 Like block full-implicit, but with single-line scope closed by  Like block full-implicit, but with single-line scope closed by the
 .Sx Reserved Characters  end of the line.
 or end of line.  
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBbody...\(rB \(lBres...\(rB  \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBbody...\(rB \(lBres...\(rB
 .Ed  .Ed
 .  
 .Pp  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" -compact -offset indent  .Bl -column "MacroX" "CallableX" "ParsedX" -compact -offset indent
 .It Em Macro Ta Em Callable Ta Em Parsable  .It Em Macro Ta Em Callable Ta Em Parsed
 .It Sx \&Aq  Ta    Yes      Ta    Yes  .It Sx \&Aq  Ta    Yes      Ta    Yes
 .It Sx \&Bq  Ta    Yes      Ta    Yes  .It Sx \&Bq  Ta    Yes      Ta    Yes
 .It Sx \&Brq Ta    Yes      Ta    Yes  .It Sx \&Brq Ta    Yes      Ta    Yes
Line 497  or end of line.
Line 807  or end of line.
 .It Sx \&Ql  Ta    Yes      Ta    Yes  .It Sx \&Ql  Ta    Yes      Ta    Yes
 .It Sx \&Qq  Ta    Yes      Ta    Yes  .It Sx \&Qq  Ta    Yes      Ta    Yes
 .It Sx \&Sq  Ta    Yes      Ta    Yes  .It Sx \&Sq  Ta    Yes      Ta    Yes
   .It Sx \&Vt  Ta    Yes      Ta    Yes
 .El  .El
 .  .Pp
 .  Note that the
   .Sx \&Vt
   macro is a
   .Sx Block partial-implicit
   only when invoked as the first macro
   in a
   .Em SYNOPSIS
   section line, else it is
   .Sx In-line .
   .Ss Special block macro
   The
   .Sx \&Ta
   macro can only be used below
   .Sx \&It
   in
   .Sx \&Bl Fl column
   lists.
   It delimits blocks representing table cells;
   these blocks have bodies, but no heads.
   .Pp
   .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXX" -compact -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
   .It Sx \&Ta  Ta    Yes      Ta    Yes    Ta closed by Sx \&Ta , Sx \&It
   .El
 .Ss In-line  .Ss In-line
 Closed by  Closed by the end of the line, fixed argument lengths,
 .Sx Reserved Characters ,  and/or subsequent macros.
 end of line, fixed argument lengths, and/or subsequent macros.  In-line  In-line macros have only text children.
 macros have only text children.  If a number (or inequality) of  If a number (or inequality) of arguments is
 arguments is  
 .Pq n ,  .Pq n ,
 then the macro accepts an arbitrary number of arguments.  then the macro accepts an arbitrary number of arguments.
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB \(lbres...\(rb  \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB \(lBres...\(rB
   
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB Yc...  \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB Yc...
   
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB arg0 arg1 argN  \&.Yo \(lB\-arg \(lBval...\(rB\(rB arg0 arg1 argN
 .Ed  .Ed
 .  
 .Pp  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" "Arguments" -compact -offset indent  .Bl -column "MacroX" "CallableX" "ParsedX" "Arguments" -compact -offset indent
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Arguments  .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Arguments
 .It Sx \&%A  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&%A  Ta    \&No     Ta    \&No     Ta    >0
 .It Sx \&%B  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&%B  Ta    \&No     Ta    \&No     Ta    >0
 .It Sx \&%C  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&%C  Ta    \&No     Ta    \&No     Ta    >0
Line 528  then the macro accepts an arbitrary number of argument
Line 860  then the macro accepts an arbitrary number of argument
 .It Sx \&%N  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&%N  Ta    \&No     Ta    \&No     Ta    >0
 .It Sx \&%O  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&%O  Ta    \&No     Ta    \&No     Ta    >0
 .It Sx \&%P  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&%P  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%Q  Ta    \&No     Ta    \&No     Ta    >0
 .It Sx \&%R  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&%R  Ta    \&No     Ta    \&No     Ta    >0
 .It Sx \&%T  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&%T  Ta    \&No     Ta    \&No     Ta    >0
   .It Sx \&%U  Ta    \&No     Ta    \&No     Ta    >0
 .It Sx \&%V  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&%V  Ta    \&No     Ta    \&No     Ta    >0
 .It Sx \&Ad  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Ad  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&An  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&An  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Ap  Ta    Yes      Ta    Yes      Ta    0  .It Sx \&Ap  Ta    Yes      Ta    Yes      Ta    0
 .It Sx \&Ar  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Ar  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&At  Ta    Yes      Ta    Yes      Ta    1  .It Sx \&At  Ta    Yes      Ta    Yes      Ta    1
Line 540  then the macro accepts an arbitrary number of argument
Line 874  then the macro accepts an arbitrary number of argument
 .It Sx \&Bt  Ta    \&No     Ta    \&No     Ta    0  .It Sx \&Bt  Ta    \&No     Ta    \&No     Ta    0
 .It Sx \&Bx  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Bx  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Cd  Ta    Yes      Ta    Yes      Ta    >0  .It Sx \&Cd  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Cm  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Cm  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Db  Ta    \&No     Ta    \&No     Ta    1  .It Sx \&Db  Ta    \&No     Ta    \&No     Ta    1
 .It Sx \&Dd  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&Dd  Ta    \&No     Ta    \&No     Ta    n
 .It Sx \&Dt  Ta    \&No     Ta    \&No     Ta    n  .It Sx \&Dt  Ta    \&No     Ta    \&No     Ta    n
 .It Sx \&Dv  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Dv  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Dx  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Dx  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Em  Ta    Yes      Ta    Yes      Ta    >0  .It Sx \&Em  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&En  Ta    \&No     Ta    \&No     Ta    0  .It Sx \&En  Ta    \&No     Ta    \&No     Ta    0
 .It Sx \&Er  Ta    Yes      Ta    Yes      Ta    >0  .It Sx \&Er  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Es  Ta    \&No     Ta    \&No     Ta    0  .It Sx \&Es  Ta    \&No     Ta    \&No     Ta    0
 .It Sx \&Ev  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Ev  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Ex  Ta    \&No     Ta    \&No     Ta    n  .It Sx \&Ex  Ta    \&No     Ta    \&No     Ta    n
 .It Sx \&Fa  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Fa  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Fd  Ta    \&No     Ta    \&No     Ta    >0  .It Sx \&Fd  Ta    \&No     Ta    \&No     Ta    >0
 .It Sx \&Fl  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Fl  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Fn  Ta    Yes      Ta    Yes      Ta    >0  .It Sx \&Fn  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Fr  Ta    \&No     Ta    \&No     Ta    n  .It Sx \&Fr  Ta    \&No     Ta    \&No     Ta    n
 .It Sx \&Ft  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Ft  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Fx  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Fx  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Hf  Ta    \&No     Ta    \&No     Ta    n  .It Sx \&Hf  Ta    \&No     Ta    \&No     Ta    n
 .It Sx \&Ic  Ta    Yes      Ta    Yes      Ta    >0  .It Sx \&Ic  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&In  Ta    \&No     Ta    \&No     Ta    n  .It Sx \&In  Ta    \&No     Ta    \&No     Ta    1
 .It Sx \&Lb  Ta    \&No     Ta    \&No     Ta    1  .It Sx \&Lb  Ta    \&No     Ta    \&No     Ta    1
 .It Sx \&Li  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Li  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Lk  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Lk  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Lp  Ta    \&No     Ta    \&No     Ta    0  .It Sx \&Lp  Ta    \&No     Ta    \&No     Ta    0
 .It Sx \&Ms  Ta    Yes      Ta    Yes      Ta    >0  .It Sx \&Ms  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Mt  Ta    Yes      Ta    Yes      Ta    >0  .It Sx \&Mt  Ta    Yes      Ta    Yes      Ta    >0
Line 576  then the macro accepts an arbitrary number of argument
Line 910  then the macro accepts an arbitrary number of argument
 .It Sx \&Ot  Ta    \&No     Ta    \&No     Ta    n  .It Sx \&Ot  Ta    \&No     Ta    \&No     Ta    n
 .It Sx \&Ox  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Ox  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Pa  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Pa  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Pf  Ta    \&No     Ta    Yes      Ta    1  .It Sx \&Pf  Ta    Yes      Ta    Yes      Ta    1
 .It Sx \&Pp  Ta    \&No     Ta    \&No     Ta    0  .It Sx \&Pp  Ta    \&No     Ta    \&No     Ta    0
 .It Sx \&Rv  Ta    \&No     Ta    \&No     Ta    n  .It Sx \&Rv  Ta    \&No     Ta    \&No     Ta    n
 .It Sx \&Sm  Ta    \&No     Ta    \&No     Ta    1  .It Sx \&Sm  Ta    \&No     Ta    \&No     Ta    1
Line 588  then the macro accepts an arbitrary number of argument
Line 922  then the macro accepts an arbitrary number of argument
 .It Sx \&Ux  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Ux  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Va  Ta    Yes      Ta    Yes      Ta    n  .It Sx \&Va  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Vt  Ta    Yes      Ta    Yes      Ta    >0  .It Sx \&Vt  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&Xr  Ta    Yes      Ta    Yes      Ta    >0, <3  .It Sx \&Xr  Ta    Yes      Ta    Yes      Ta    >0
 .It Sx \&br  Ta    \&No     Ta    \&No     Ta    0  .It Sx \&br  Ta    \&No     Ta    \&No     Ta    0
 .It Sx \&sp  Ta    \&No     Ta    \&No     Ta    1  .It Sx \&sp  Ta    \&No     Ta    \&No     Ta    1
 .El  .El
 .  .Ss Delimiters
 .  When a macro argument consists of one single input character
   considered as a delimiter, the argument gets special handling.
   This does not apply when delimiters appear in arguments containing
   more than one character.
   Consequently, to prevent special handling and just handle it
   like any other argument, a delimiter can be escaped by prepending
   a zero-width space
   .Pq Sq \e& .
   In text lines, delimiters never need escaping, but may be used
   as normal punctuation.
   .Pp
   For many macros, when the leading arguments are opening delimiters,
   these delimiters are put before the macro scope,
   and when the trailing arguments are closing delimiters,
   these delimiters are put after the macro scope.
   For example,
   .Pp
   .D1 Pf \. \&Aq "( [ word ] ) ."
   .Pp
   renders as:
   .Pp
   .D1 Aq ( [ word ] ) .
   .Pp
   Opening delimiters are:
   .Pp
   .Bl -tag -width Ds -offset indent -compact
   .It \&(
   left parenthesis
   .It \&[
   left bracket
   .El
   .Pp
   Closing delimiters are:
   .Pp
   .Bl -tag -width Ds -offset indent -compact
   .It \&.
   period
   .It \&,
   comma
   .It \&:
   colon
   .It \&;
   semicolon
   .It \&)
   right parenthesis
   .It \&]
   right bracket
   .It \&?
   question mark
   .It \&!
   exclamation mark
   .El
   .Pp
   Note that even a period preceded by a backslash
   .Pq Sq \e.\&
   gets this special handling; use
   .Sq \e&.
   to prevent that.
   .Pp
   Many in-line macros interrupt their scope when they encounter
   delimiters, and resume their scope when more arguments follow that
   are not delimiters.
   For example,
   .Pp
   .D1 Pf \. \&Fl "a ( b | c \e*(Ba d ) e"
   .Pp
   renders as:
   .Pp
   .D1 Fl a ( b | c \*(Ba d ) e
   .Pp
   This applies to both opening and closing delimiters,
   and also to the middle delimiter:
   .Pp
   .Bl -tag -width Ds -offset indent -compact
   .It \&|
   vertical bar
   .El
   .Pp
   As a special case, the predefined string \e*(Ba is handled and rendered
   in the same way as a plain
   .Sq \&|
   character.
   Using this predefined string is not recommended in new manuals.
 .Sh REFERENCE  .Sh REFERENCE
 This section is a canonical reference of all macros, arranged  This section is a canonical reference of all macros, arranged
 alphabetically.  For the scoping of individual macros, see  alphabetically.
   For the scoping of individual macros, see
 .Sx MACRO SYNTAX .  .Sx MACRO SYNTAX .
 .  
 .Ss \&%A  .Ss \&%A
 Author name of an  Author name of an
 .Sx \&Rs  .Sx \&Rs
 block.  Multiple authors should each be accorded their own  block.
   Multiple authors should each be accorded their own
 .Sx \%%A  .Sx \%%A
 line.  line.
 .Pp  
 Author names should be ordered with full or abbreviated forename(s)  Author names should be ordered with full or abbreviated forename(s)
 first, then full surname.  first, then full surname.
 .  
 .Ss \&%B  .Ss \&%B
 Book title of an  Book title of an
 .Sx \&Rs  .Sx \&Rs
 block.  This macro may also be used in a non-bibliographic context when  block.
   This macro may also be used in a non-bibliographic context when
 referring to book titles.  referring to book titles.
 .  
 .Ss \&%C  .Ss \&%C
 Publication city or location of an  Publication city or location of an
 .Sx \&Rs  .Sx \&Rs
 block.  block.
 .Pp  
 .Em Remarks :  
 this macro is not implemented in  
 .Xr groff 1 .  
 .  
 .Ss \&%D  .Ss \&%D
 Publication date of an  Publication date of an
 .Sx \&Rs  .Sx \&Rs
 block.  This should follow the canonical syntax for  block.
 .Sx Dates .  Recommended formats of arguments are
 .  .Ar month day , year
   or just
   .Ar year .
 .Ss \&%I  .Ss \&%I
 Publisher or issuer name of an  Publisher or issuer name of an
 .Sx \&Rs  .Sx \&Rs
 block.  block.
 .  
 .Ss \&%J  .Ss \&%J
 Journal name of an  Journal name of an
 .Sx \&Rs  .Sx \&Rs
 block.  block.
 .  
 .Ss \&%N  .Ss \&%N
 Issue number (usually for journals) of an  Issue number (usually for journals) of an
 .Sx \&Rs  .Sx \&Rs
 block.  block.
 .  
 .Ss \&%O  .Ss \&%O
 Optional information of an  Optional information of an
 .Sx \&Rs  .Sx \&Rs
 block.  block.
 .  
 .Ss \&%P  .Ss \&%P
 Book or journal page number of an  Book or journal page number of an
 .Sx \&Rs  .Sx \&Rs
 block.  block.
 .  
 .Ss \&%Q  .Ss \&%Q
 Institutional author (school, government, etc.) of an  Institutional author (school, government, etc.) of an
 .Sx \&Rs  .Sx \&Rs
 block.  Multiple institutional authors should each be accorded their own  block.
   Multiple institutional authors should each be accorded their own
 .Sx \&%Q  .Sx \&%Q
 line.  line.
 .  
 .Ss \&%R  .Ss \&%R
 Technical report name of an  Technical report name of an
 .Sx \&Rs  .Sx \&Rs
 block.  block.
 .  
 .Ss \&%T  .Ss \&%T
 Article title of an  Article title of an
 .Sx \&Rs  .Sx \&Rs
 block.  This macro may also be used in a non-bibliographical context  block.
 when referring to article titles.  This macro may also be used in a non-bibliographical context when
 .  referring to article titles.
   .Ss \&%U
   URI of reference document.
 .Ss \&%V  .Ss \&%V
 Volume number of an  Volume number of an
 .Sx \&Rs  .Sx \&Rs
 block.  block.
 .  
 .Ss \&Ac  .Ss \&Ac
 Closes an  Close an
 .Sx \&Ao  .Sx \&Ao
 block.  Does not have any tail arguments.  block.
 .  Does not have any tail arguments.
 .Ss \&Ad  .Ss \&Ad
 Address construct: usually in the context of an computational address in  Memory address.
 memory, not a physical (post) address.  Do not use this for postal addresses.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Ad [0,$]
 \&.Ad [0,$]  .Dl \&.Ad 0x00000000
 \&.Ad 0x00000000  
 .Ed  
 .  
 .Ss \&An  .Ss \&An
 Author name.  This macro may alternatively accepts the following  Author name.
 arguments, although these may not be specified along with a parameter:  Can be used both for the authors of the program, function, or driver
 .Bl -tag -width 12n -offset indent  documented in the manual, or for the authors of the manual itself.
   Requires either the name of an author or one of the following arguments:
   .Pp
   .Bl -tag -width "-nosplitX" -offset indent -compact
 .It Fl split  .It Fl split
 Renders a line break is rendered before each author listing.  Start a new output line before each subsequent invocation of
   .Sx \&An .
 .It Fl nosplit  .It Fl nosplit
 The opposite of  The opposite of
 .Fl split .  .Fl split .
 .El  .El
 .Pp  .Pp
 In the AUTHORS section, the default is not to split the first author  The default is
 listing, but all subsequent author listings, whether or not they're  .Fl nosplit .
 interspersed by other macros or text, are split.  Thus, specifying  The effect of selecting either of the
 .Fl split  .Fl split
 will cause the first listing also to be split.  If not in the AUTHORS  modes ends at the beginning of the
 section, the default is not to split.  .Em AUTHORS
   section.
   In the
   .Em AUTHORS
   section, the default is
   .Fl nosplit
   for the first author listing and
   .Fl split
   for all other author listings.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.An -nosplit
 \&.An -nosplit  .Dl \&.An Kristaps Dzonsons \&Aq kristaps@bsd.lv
 \&.An J. E. Hopcraft ,  
 \&.An J. D. Ullman .  
 .Ed  
 .Pp  
 .Em Remarks :  
 the effects of  
 .Fl split  
 or  
 .Fl nosplit  
 are re-set when entering the AUTHORS section, so if one specifies  
 .Sx \&An Fl nosplit  
 in the general document body, it must be re-specified in the AUTHORS  
 section.  
 .  
 .Ss \&Ao  .Ss \&Ao
 Begins a block enclosed by angled brackets.  Does not have any head  Begin a block enclosed by angle brackets.
 arguments.  Does not have any head arguments.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Fl -key= \&Ns \&Ao \&Ar val \&Ac
 \&.Fl -key= Ns Ao Ar val Ac  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Aq .  .Sx \&Aq .
 .  
 .Ss \&Ap  .Ss \&Ap
 Inserts an apostrophe without any surrounding white-space.  This is  Inserts an apostrophe without any surrounding whitespace.
 generally used as a grammatic device when referring to the verb form of  This is generally used as a grammatical device when referring to the verb
 a function:  form of a function.
 .Bd -literal -offset indent  .Pp
 \&.Fn execve Ap d  Examples:
 .Ed  .Dl \&.Fn execve \&Ap d
 .  
 .Ss \&Aq  .Ss \&Aq
 Encloses its arguments in angled brackets.  Encloses its arguments in angle brackets.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Fl -key= \&Ns \&Aq \&Ar val
 \&.Fl -key= Ns Aq Ar val  
 .Ed  
 .Pp  .Pp
 .Em Remarks :  .Em Remarks :
 this macro is often abused for rendering URIs, which should instead use  this macro is often abused for rendering URIs, which should instead use
Line 768  statements, which should use
Line 1164  statements, which should use
 .Pp  .Pp
 See also  See also
 .Sx \&Ao .  .Sx \&Ao .
 .  
 .Ss \&Ar  .Ss \&Ar
 Command arguments.  If an argument is not provided, the strings  Command arguments.
 .Dq file ...  If an argument is not provided, the string
 are used as a default.  .Dq file ...\&
   is used as a default.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl ".Fl o Ar file"
 \&.Fl o Ns Ar file1  .Dl ".Ar"
 \&.Ar  .Dl ".Ar arg1 , arg2 ."
 \&.Ar arg1 , arg2 .  .Pp
 .Ed  The arguments to the
 .  .Sx \&Ar
   macro are names and placeholders for command arguments;
   for fixed strings to be passed verbatim as arguments, use
   .Sx \&Fl
   or
   .Sx \&Cm .
 .Ss \&At  .Ss \&At
 Formats an AT&T version.  Accepts at most one parameter:  Formats an AT&T version.
 .Bl -tag -width 12n -offset indent  Accepts one optional argument:
   .Pp
   .Bl -tag -width "v[1-7] | 32vX" -offset indent -compact
 .It Cm v[1-7] | 32v  .It Cm v[1-7] | 32v
 A version of  A version of
 .At .  .At .
   .It Cm III
   .At III .
 .It Cm V[.[1-4]]?  .It Cm V[.[1-4]]?
 A system version of  A version of
 .At .  .At V .
 .El  .El
 .Pp  .Pp
 Note that these parameters do not begin with a hyphen.  Note that these arguments do not begin with a hyphen.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.At
 \&.At  .Dl \&.At III
 \&.At V.1  .Dl \&.At V.1
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Bx ,  
 .Sx \&Bsx ,  .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
 .Sx \&Fx ,  .Sx \&Fx ,
 .Sx \&Nx ,  .Sx \&Nx ,
 .Sx \&Ox ,  .Sx \&Ox ,
 and  and
 .Sx \&Ux .  .Sx \&Ux .
 .  
 .Ss \&Bc  .Ss \&Bc
 Closes a  Close a
 .Sx \&Bo  .Sx \&Bo
 block.  Does not have any tail arguments.  block.
 .  Does not have any tail arguments.
 .Ss \&Bd  .Ss \&Bd
 Begins a display block.  A display is collection of macros or text which  Begin a display block.
 may be collectively offset or justified in a manner different from that  Its syntax is as follows:
 of the enclosing context.  By default, the block is preceded by a  .Bd -ragged -offset indent
 vertical space.  .Pf \. Sx \&Bd
   .Fl Ns Ar type
   .Op Fl offset Ar width
   .Op Fl compact
   .Ed
 .Pp  .Pp
 Each display is associated with a type, which must be one of the  Display blocks are used to select a different indentation and
 following arguments:  justification than the one used by the surrounding text.
 .Bl -tag -width 12n -offset indent  They may contain both macro lines and text lines.
 .It Fl ragged  By default, a display block is preceded by a vertical space.
 Only left-justify the block.  .Pp
 .It Fl unfilled  The
 Do not justify the block at all.  .Ar type
   must be one of the following:
   .Bl -tag -width 13n -offset indent
   .It Fl centered
   Produce one output line from each input line, and centre-justify each line.
   Using this display type is not recommended; many
   .Nm
   implementations render it poorly.
 .It Fl filled  .It Fl filled
 Left- and right-justify the block.  Change the positions of line breaks to fill each line, and left- and
   right-justify the resulting block.
 .It Fl literal  .It Fl literal
 Alias for  Produce one output line from each input line,
 .Fl unfilled .  and do not justify the block at all.
 .It Fl centered  Preserve white space as it appears in the input.
 Centre-justify each line.  Always use a constant-width font.
   Use this for displaying source code.
   .It Fl ragged
   Change the positions of line breaks to fill each line, and left-justify
   the resulting block.
   .It Fl unfilled
   The same as
   .Fl literal ,
   but using the same font as for normal text, which is a variable width font
   if supported by the output device.
 .El  .El
 .Pp  .Pp
 The type must be provided first.  Secondary arguments are as follows:  The
 .Bl -tag -width 12n -offset indent  .Ar type
   must be provided first.
   Additional arguments may follow:
   .Bl -tag -width 13n -offset indent
 .It Fl offset Ar width  .It Fl offset Ar width
 Offset by the value of  Indent the display by the
 .Ar width ,  .Ar width ,
 which is interpreted as one of the following, specified in order:  which may be one of the following:
 .Bl -item  .Bl -item
 .It  .It
 As one of the pre-defined strings  One of the pre-defined strings
 .Ar indent ,  .Cm indent ,
 the width of standard indentation;  the width of a standard indentation (six constant width characters);
 .Ar indent-two ,  .Cm indent-two ,
 twice  twice
 .Ar indent ;  .Cm indent ;
 .Ar left ,  .Cm left ,
 which has no effect ;  which has no effect;
 .Ar right ,  .Cm right ,
 which justifies to the right margin; and  which justifies to the right margin; or
 .Ar center ,  .Cm center ,
 which aligns around an imagined centre axis.  which aligns around an imagined centre axis.
 .It  .It
 As a precalculated width for a named macro.  The most popular is the  A macro invocation, which selects a predefined width
 imaginary macro  associated with that macro.
 .Ar Ds ,  The most popular is the imaginary macro
   .Ar \&Ds ,
 which resolves to  which resolves to
 .Ar 6n .  .Sy 6n .
 .It  .It
 As a scaling unit following the syntax described in  A width using the syntax described in
 .Sx Scaling Widths .  .Sx Scaling Widths .
 .It  .It
 As the calculated string length of the opaque string.  An arbitrary string, which indents by the length of this string.
 .El  .El
 .Pp  .Pp
 If unset, it will revert to the value of  When the argument is missing,
 .Ar 8n  .Fl offset
 as described in  is ignored.
 .Sx Scaling Widths .  
 .It Fl compact  .It Fl compact
 Do not assert a vertical space before the block.  Do not assert vertical space before the display.
 .It Fl file Ar file  
 Prepend the file  
 .Ar file  
 before any text or macros within the block.  
 .El  .El
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Bd \-unfilled \-offset two-indent \-compact  \&.Bd \-literal \-offset indent \-compact
    Hello       world.     Hello       world.
 \&.Ed  \&.Ed
 .Ed  .Ed
 .  .Pp
   See also
   .Sx \&D1
   and
   .Sx \&Dl .
 .Ss \&Bf  .Ss \&Bf
   Change the font mode for a scoped block of text.
   Its syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Bf
   .Oo
   .Fl emphasis | literal | symbolic |
   .Cm \&Em | \&Li | \&Sy
   .Oc
   .Ed
   .Pp
   The
   .Fl emphasis
   and
   .Cm \&Em
   argument are equivalent, as are
   .Fl symbolic
   and
   .Cm \&Sy ,
   and
   .Fl literal
   and
   .Cm \&Li .
   Without an argument, this macro does nothing.
   The font mode continues until broken by a new font mode in a nested
   scope or
   .Sx \&Ef
   is encountered.
   .Pp
   See also
   .Sx \&Li ,
   .Sx \&Ef ,
   .Sx \&Em ,
   and
   .Sx \&Sy .
 .Ss \&Bk  .Ss \&Bk
   For each macro, keep its output together on the same output line,
   until the end of the macro or the end of the input line is reached,
   whichever comes first.
   Line breaks in text lines are unaffected.
   The syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Bk Fl words
   .Pp
   The
   .Fl words
   argument is required; additional arguments are ignored.
   .Pp
   The following example will not break within each
   .Sx \&Op
   macro line:
   .Bd -literal -offset indent
   \&.Bk \-words
   \&.Op Fl f Ar flags
   \&.Op Fl o Ar output
   \&.Ek
   .Ed
   .Pp
   Be careful in using over-long lines within a keep block!
   Doing so will clobber the right margin.
 .Ss \&Bl  .Ss \&Bl
 .  Begin a list.
   Lists consist of items specified using the
   .Sx \&It
   macro, containing a head or a body or both.
   The list syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Bl
   .Fl Ns Ar type
   .Op Fl width Ar val
   .Op Fl offset Ar val
   .Op Fl compact
   .Op HEAD ...
   .Ed
   .Pp
   The list
   .Ar type
   is mandatory and must be specified first.
   The
   .Fl width
   and
   .Fl offset
   arguments accept
   .Sx Scaling Widths
   or use the length of the given string.
   The
   .Fl offset
   is a global indentation for the whole list, affecting both item heads
   and bodies.
   For those list types supporting it, the
   .Fl width
   argument requests an additional indentation of item bodies,
   to be added to the
   .Fl offset .
   Unless the
   .Fl compact
   argument is specified, list entries are separated by vertical space.
   .Pp
   A list must specify one of the following list types:
   .Bl -tag -width 12n -offset indent
   .It Fl bullet
   No item heads can be specified, but a bullet will be printed at the head
   of each item.
   Item bodies start on the same output line as the bullet
   and are indented according to the
   .Fl width
   argument.
   .It Fl column
   A columnated list.
   The
   .Fl width
   argument has no effect; instead, each argument specifies the width
   of one column, using either the
   .Sx Scaling Widths
   syntax or the string length of the argument.
   If the first line of the body of a
   .Fl column
   list is not an
   .Sx \&It
   macro line,
   .Sx \&It
   contexts spanning one input line each are implied until an
   .Sx \&It
   macro line is encountered, at which point items start being interpreted as
   described in the
   .Sx \&It
   documentation.
   .It Fl dash
   Like
   .Fl bullet ,
   except that dashes are used in place of bullets.
   .It Fl diag
   Like
   .Fl inset ,
   except that item heads are not parsed for macro invocations.
   Most often used in the
   .Em DIAGNOSTICS
   section with error constants in the item heads.
   .It Fl enum
   A numbered list.
   No item heads can be specified.
   Formatted like
   .Fl bullet ,
   except that cardinal numbers are used in place of bullets,
   starting at 1.
   .It Fl hang
   Like
   .Fl tag ,
   except that the first lines of item bodies are not indented, but follow
   the item heads like in
   .Fl inset
   lists.
   .It Fl hyphen
   Synonym for
   .Fl dash .
   .It Fl inset
   Item bodies follow items heads on the same line, using normal inter-word
   spacing.
   Bodies are not indented, and the
   .Fl width
   argument is ignored.
   .It Fl item
   No item heads can be specified, and none are printed.
   Bodies are not indented, and the
   .Fl width
   argument is ignored.
   .It Fl ohang
   Item bodies start on the line following item heads and are not indented.
   The
   .Fl width
   argument is ignored.
   .It Fl tag
   Item bodies are indented according to the
   .Fl width
   argument.
   When an item head fits inside the indentation, the item body follows
   this head on the same output line.
   Otherwise, the body starts on the output line following the head.
   .El
   .Pp
   Lists may be nested within lists and displays.
   Nesting of
   .Fl column
   and
   .Fl enum
   lists may not be portable.
   .Pp
   See also
   .Sx \&El
   and
   .Sx \&It .
 .Ss \&Bo  .Ss \&Bo
 Begins a block enclosed by square brackets.  Does not have any head  Begin a block enclosed by square brackets.
 arguments.  Does not have any head arguments.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Bd -literal -offset indent -compact
 \&.Bo 1 ,  \&.Bo 1 ,
 \&.Dv BUFSIZ Bc  \&.Dv BUFSIZ \&Bc
 .Ed  .Ed
 .Pp  .Pp
 See also  See also
 .Sx \&Bq .  .Sx \&Bq .
 .  
 .Ss \&Bq  .Ss \&Bq
 Encloses its arguments in square brackets.  Encloses its arguments in square brackets.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Bq 1 , \&Dv BUFSIZ
 \&.Bq 1 , Dv BUFSIZ  
 .Ed  
 .Pp  .Pp
 .Em Remarks :  .Em Remarks :
 this macro is sometimes abused to emulate optional arguments for  this macro is sometimes abused to emulate optional arguments for
Line 923  and
Line 1535  and
 .Pp  .Pp
 See also  See also
 .Sx \&Bo .  .Sx \&Bo .
 .  
 .Ss \&Brc  .Ss \&Brc
 Closes a  Close a
 .Sx \&Bro  .Sx \&Bro
 block.  Does not have any tail arguments.  block.
 .  Does not have any tail arguments.
 .Ss \&Bro  .Ss \&Bro
 Begins a block enclosed by curly braces.  Does not have any head  Begin a block enclosed by curly braces.
 arguments.  Does not have any head arguments.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Bd -literal -offset indent -compact
 \&.Bro 1 , ... ,  \&.Bro 1 , ... ,
 \&.Va n Brc  \&.Va n \&Brc
 .Ed  .Ed
 .Pp  .Pp
 See also  See also
 .Sx \&Brq .  .Sx \&Brq .
 .  
 .Ss \&Brq  .Ss \&Brq
 Encloses its arguments in curly braces.  Encloses its arguments in curly braces.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Brq 1 , ... , \&Va n
 \&.Brq 1 , ... , Va n  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Bro .  .Sx \&Bro .
 .  
 .Ss \&Bsx  .Ss \&Bsx
 Format the BSD/OS version provided as an argument, or a default value if  Format the BSD/OS version provided as an argument, or a default value if
 no argument is provided.  no argument is provided.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Bsx 1.0
 \&.Bsx 1.0  .Dl \&.Bsx
 \&.Bsx  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Sx \&At ,
 .Sx \&Bx ,  .Sx \&Bx ,
   .Sx \&Dx ,
 .Sx \&Fx ,  .Sx \&Fx ,
 .Sx \&Nx ,  .Sx \&Nx ,
 .Sx \&Ox ,  .Sx \&Ox ,
 and  and
 .Sx \&Ux .  .Sx \&Ux .
 .  
 .Ss \&Bt  .Ss \&Bt
   Prints
   .Dq is currently in beta test.
 .Ss \&Bx  .Ss \&Bx
 Format the BSD version provided as an argument, or a default value if no  Format the BSD version provided as an argument, or a default value if no
 argument is provided.  argument is provided.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Bx 4.3 Tahoe
 \&.Bx 4.4  .Dl \&.Bx 4.4
 \&.Bx  .Dl \&.Bx
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Sx \&At ,
 .Sx \&Bsx ,  .Sx \&Bsx ,
   .Sx \&Dx ,
 .Sx \&Fx ,  .Sx \&Fx ,
 .Sx \&Nx ,  .Sx \&Nx ,
 .Sx \&Ox ,  .Sx \&Ox ,
 and  and
 .Sx \&Ux .  .Sx \&Ux .
 .  
 .Ss \&Cd  .Ss \&Cd
   Kernel configuration declaration.
   This denotes strings accepted by
   .Xr config 8 .
   It is most often used in section 4 manual pages.
   .Pp
   Examples:
   .Dl \&.Cd device le0 at scode?
   .Pp
   .Em Remarks :
   this macro is commonly abused by using quoted literals to retain
   whitespace and align consecutive
   .Sx \&Cd
   declarations.
   This practise is discouraged.
 .Ss \&Cm  .Ss \&Cm
   Command modifiers.
   Typically used for fixed strings passed as arguments, unless
   .Sx \&Fl
   is more appropriate.
   Also useful when specifying configuration options or keys.
   .Pp
   Examples:
   .Dl ".Nm mt Fl f Ar device Cm rewind"
   .Dl ".Nm ps Fl o Cm pid , Ns Cm command"
   .Dl ".Nm dd Cm if= Ns Ar file1 Cm of= Ns Ar file2"
   .Dl ".Cm IdentityFile Pa ~/.ssh/id_rsa"
   .Dl ".Cm LogLevel Dv DEBUG"
 .Ss \&D1  .Ss \&D1
   One-line indented display.
   This is formatted by the default rules and is useful for simple indented
   statements.
   It is followed by a newline.
   .Pp
   Examples:
   .Dl \&.D1 \&Fl abcdefgh
   .Pp
   See also
   .Sx \&Bd
   and
   .Sx \&Dl .
 .Ss \&Db  .Ss \&Db
   Switch debugging mode.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Db Cm on | off
   .Pp
   This macro is ignored by
   .Xr mandoc 1 .
 .Ss \&Dc  .Ss \&Dc
   Close a
   .Sx \&Do
   block.
   Does not have any tail arguments.
 .Ss \&Dd  .Ss \&Dd
   Document date.
   This is the mandatory first macro of any
   .Nm
   manual.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Dd Ar month day , year
   .Pp
   The
   .Ar month
   is the full English month name, the
   .Ar day
   is an optionally zero-padded numeral, and the
   .Ar year
   is the full four-digit year.
   .Pp
   Other arguments are not portable; the
   .Xr mandoc 1
   utility handles them as follows:
   .Bl -dash -offset 3n -compact
   .It
   To have the date automatically filled in by the
   .Ox
   version of
   .Xr cvs 1 ,
   the special string
   .Dq $\&Mdocdate$
   can be given as an argument.
   .It
   A few alternative date formats are accepted as well
   and converted to the standard form.
   .It
   If a date string cannot be parsed, it is used verbatim.
   .It
   If no date string is given, the current date is used.
   .El
   .Pp
   Examples:
   .Dl \&.Dd $\&Mdocdate$
   .Dl \&.Dd $\&Mdocdate: July 21 2007$
   .Dl \&.Dd July 21, 2007
   .Pp
   See also
   .Sx \&Dt
   and
   .Sx \&Os .
 .Ss \&Dl  .Ss \&Dl
   One-line intended display.
   This is formatted as literal text and is useful for commands and
   invocations.
   It is followed by a newline.
   .Pp
   Examples:
   .Dl \&.Dl % mandoc mdoc.7 \e(ba less
   .Pp
   See also
   .Sx \&Bd
   and
   .Sx \&D1 .
 .Ss \&Do  .Ss \&Do
   Begin a block enclosed by double quotes.
   Does not have any head arguments.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Do
   April is the cruellest month
   \&.Dc
   \e(em T.S. Eliot
   .Ed
   .Pp
   See also
   .Sx \&Dq .
 .Ss \&Dq  .Ss \&Dq
   Encloses its arguments in
   .Dq typographic
   double-quotes.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Dq April is the cruellest month
   \e(em T.S. Eliot
   .Ed
   .Pp
   See also
   .Sx \&Qq ,
   .Sx \&Sq ,
   and
   .Sx \&Do .
 .Ss \&Dt  .Ss \&Dt
   Document title.
   This is the mandatory second macro of any
   .Nm
   file.
   Its syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Dt
   .Oo
   .Ar title
   .Oo
   .Ar section
   .Op Ar volume | arch
   .Oc
   .Oc
   .Ed
   .Pp
   Its arguments are as follows:
   .Bl -tag -width Ds -offset Ds
   .It Ar title
   The document's title (name), defaulting to
   .Dq UNKNOWN
   if unspecified.
   It should be capitalised.
   .It Ar section
   The manual section.
   This may be one of
   .Ar 1
   .Pq utilities ,
   .Ar 2
   .Pq system calls ,
   .Ar 3
   .Pq libraries ,
   .Ar 3p
   .Pq Perl libraries ,
   .Ar 4
   .Pq devices ,
   .Ar 5
   .Pq file formats ,
   .Ar 6
   .Pq games ,
   .Ar 7
   .Pq miscellaneous ,
   .Ar 8
   .Pq system utilities ,
   .Ar 9
   .Pq kernel functions ,
   .Ar X11
   .Pq X Window System ,
   .Ar X11R6
   .Pq X Window System ,
   .Ar unass
   .Pq unassociated ,
   .Ar local
   .Pq local system ,
   .Ar draft
   .Pq draft manual ,
   or
   .Ar paper
   .Pq paper .
   It should correspond to the manual's filename suffix and defaults to
   .Dq 1
   if unspecified.
   .It Ar volume
   This overrides the volume inferred from
   .Ar section .
   This field is optional, and if specified, must be one of
   .Ar USD
   .Pq users' supplementary documents ,
   .Ar PS1
   .Pq programmers' supplementary documents ,
   .Ar AMD
   .Pq administrators' supplementary documents ,
   .Ar SMM
   .Pq system managers' manuals ,
   .Ar URM
   .Pq users' reference manuals ,
   .Ar PRM
   .Pq programmers' reference manuals ,
   .Ar KM
   .Pq kernel manuals ,
   .Ar IND
   .Pq master index ,
   .Ar MMI
   .Pq master index ,
   .Ar LOCAL
   .Pq local manuals ,
   .Ar LOC
   .Pq local manuals ,
   or
   .Ar CON
   .Pq contributed manuals .
   .It Ar arch
   This specifies a specific relevant architecture.
   If
   .Ar volume
   is not provided, it may be used in its place, else it may be used
   subsequent that.
   It, too, is optional.
   It must be one of
   .Ar alpha ,
   .Ar amd64 ,
   .Ar amiga ,
   .Ar arc ,
   .Ar arm ,
   .Ar armish ,
   .Ar aviion ,
   .Ar hp300 ,
   .Ar hppa ,
   .Ar hppa64 ,
   .Ar i386 ,
   .Ar landisk ,
   .Ar loongson ,
   .Ar luna88k ,
   .Ar mac68k ,
   .Ar macppc ,
   .Ar mips64 ,
   .Ar mvme68k ,
   .Ar mvme88k ,
   .Ar mvmeppc ,
   .Ar pmax ,
   .Ar sgi ,
   .Ar socppc ,
   .Ar sparc ,
   .Ar sparc64 ,
   .Ar sun3 ,
   .Ar vax ,
   or
   .Ar zaurus .
   .El
   .Pp
   Examples:
   .Dl \&.Dt FOO 1
   .Dl \&.Dt FOO 4 KM
   .Dl \&.Dt FOO 9 i386
   .Pp
   See also
   .Sx \&Dd
   and
   .Sx \&Os .
 .Ss \&Dv  .Ss \&Dv
   Defined variables such as preprocessor constants, constant symbols,
   enumeration values, and so on.
   .Pp
   Examples:
   .Dl \&.Dv NULL
   .Dl \&.Dv BUFSIZ
   .Dl \&.Dv STDOUT_FILENO
   .Pp
   See also
   .Sx \&Er
   and
   .Sx \&Ev
   for special-purpose constants and
   .Sx \&Va
   for variable symbols.
 .Ss \&Dx  .Ss \&Dx
   Format the DragonFly BSD version provided as an argument, or a default
   value if no argument is provided.
   .Pp
   Examples:
   .Dl \&.Dx 2.4.1
   .Dl \&.Dx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
 .Ss \&Ec  .Ss \&Ec
   Close a scope started by
   .Sx \&Eo .
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Ec Op Ar TERM
   .Pp
   The
   .Ar TERM
   argument is used as the enclosure tail, for example, specifying \e(rq
   will emulate
   .Sx \&Dc .
 .Ss \&Ed  .Ss \&Ed
   End a display context started by
   .Sx \&Bd .
 .Ss \&Ef  .Ss \&Ef
   End a font mode context started by
   .Sx \&Bf .
 .Ss \&Ek  .Ss \&Ek
   End a keep context started by
   .Sx \&Bk .
 .Ss \&El  .Ss \&El
   End a list context started by
   .Sx \&Bl .
   .Pp
   See also
   .Sx \&Bl
   and
   .Sx \&It .
 .Ss \&Em  .Ss \&Em
   Denotes text that should be
   .Em emphasised .
   Note that this is a presentation term and should not be used for
   stylistically decorating technical terms.
   Depending on the output device, this is usually represented
   using an italic font or underlined characters.
   .Pp
   Examples:
   .Dl \&.Em Warnings!
   .Dl \&.Em Remarks :
   .Pp
   See also
   .Sx \&Bf ,
   .Sx \&Li ,
   .Sx \&No ,
   and
   .Sx \&Sy .
 .Ss \&En  .Ss \&En
   This macro is obsolete and not implemented in
   .Xr mandoc 1 .
 .Ss \&Eo  .Ss \&Eo
   An arbitrary enclosure.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Eo Op Ar TERM
   .Pp
   The
   .Ar TERM
   argument is used as the enclosure head, for example, specifying \e(lq
   will emulate
   .Sx \&Do .
 .Ss \&Er  .Ss \&Er
   Error constants for definitions of the
   .Va errno
   libc global variable.
   This is most often used in section 2 and 3 manual pages.
   .Pp
   Examples:
   .Dl \&.Er EPERM
   .Dl \&.Er ENOENT
   .Pp
   See also
   .Sx \&Dv
   for general constants.
 .Ss \&Es  .Ss \&Es
   This macro is obsolete and not implemented.
 .Ss \&Ev  .Ss \&Ev
   Environmental variables such as those specified in
   .Xr environ 7 .
   .Pp
   Examples:
   .Dl \&.Ev DISPLAY
   .Dl \&.Ev PATH
   .Pp
   See also
   .Sx \&Dv
   for general constants.
 .Ss \&Ex  .Ss \&Ex
   Insert a standard sentence regarding command exit values of 0 on success
   and >0 on failure.
   This is most often used in section 1, 6, and 8 manual pages.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Ex Fl std Op Ar utility ...
   .Pp
   If
   .Ar utility
   is not specified, the document's name set by
   .Sx \&Nm
   is used.
   Multiple
   .Ar utility
   arguments are treated as separate utilities.
   .Pp
   See also
   .Sx \&Rv .
 .Ss \&Fa  .Ss \&Fa
   Function argument.
   Its syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Fa
   .Op Cm argtype
   .Cm argname
   .Ed
   .Pp
   This may be invoked for names with or without the corresponding type.
   It is also used to specify the field name of a structure.
   Most often, the
   .Sx \&Fa
   macro is used in the
   .Em SYNOPSIS
   within
   .Sx \&Fo
   section when documenting multi-line function prototypes.
   If invoked with multiple arguments, the arguments are separated by a
   comma.
   Furthermore, if the following macro is another
   .Sx \&Fa ,
   the last argument will also have a trailing comma.
   .Pp
   Examples:
   .Dl \&.Fa \(dqconst char *p\(dq
   .Dl \&.Fa \(dqint a\(dq \(dqint b\(dq \(dqint c\(dq
   .Dl \&.Fa foo
   .Pp
   See also
   .Sx \&Fo .
 .Ss \&Fc  .Ss \&Fc
   End a function context started by
   .Sx \&Fo .
 .Ss \&Fd  .Ss \&Fd
   Historically used to document include files.
   This usage has been deprecated in favour of
   .Sx \&In .
   Do not use this macro.
   .Pp
   See also
   .Sx MANUAL STRUCTURE
   and
   .Sx \&In .
 .Ss \&Fl  .Ss \&Fl
   Command-line flag or option.
   Used when listing arguments to command-line utilities.
   Prints a fixed-width hyphen
   .Sq \-
   directly followed by each argument.
   If no arguments are provided, a hyphen is printed followed by a space.
   If the argument is a macro, a hyphen is prefixed to the subsequent macro
   output.
   .Pp
   Examples:
   .Dl ".Fl R Op Fl H | L | P"
   .Dl ".Op Fl 1AaCcdFfgHhikLlmnopqRrSsTtux"
   .Dl ".Fl type Cm d Fl name Pa CVS"
   .Dl ".Fl Ar signal_number"
   .Dl ".Fl o Fl"
   .Pp
   See also
   .Sx \&Cm .
 .Ss \&Fn  .Ss \&Fn
   A function name.
   Its syntax is as follows:
   .Bd -ragged -offset indent
   .Pf \. Ns Sx \&Fn
   .Op Ar functype
   .Ar funcname
   .Op Oo Ar argtype Oc Ar argname
   .Ed
   .Pp
   Function arguments are surrounded in parenthesis and
   are delimited by commas.
   If no arguments are specified, blank parenthesis are output.
   In the
   .Em SYNOPSIS
   section, this macro starts a new output line,
   and a blank line is automatically inserted between function definitions.
   .Pp
   Examples:
   .Dl \&.Fn \*qint funcname\*q \*qint arg0\*q \*qint arg1\*q
   .Dl \&.Fn funcname \*qint arg0\*q
   .Dl \&.Fn funcname arg0
   .Pp
   .Bd -literal -offset indent -compact
   \&.Ft functype
   \&.Fn funcname
   .Ed
   .Pp
   When referring to a function documented in another manual page, use
   .Sx \&Xr
   instead.
   See also
   .Sx MANUAL STRUCTURE ,
   .Sx \&Fo ,
   and
   .Sx \&Ft .
 .Ss \&Fo  .Ss \&Fo
   Begin a function block.
   This is a multi-line version of
   .Sx \&Fn .
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Fo Ar funcname
   .Pp
   Invocations usually occur in the following context:
   .Bd -ragged -offset indent
   .Pf \. Sx \&Ft Ar functype
   .br
   .Pf \. Sx \&Fo Ar funcname
   .br
   .Pf \. Sx \&Fa Oo Ar argtype Oc Ar argname
   .br
   \&.\.\.
   .br
   .Pf \. Sx \&Fc
   .Ed
   .Pp
   A
   .Sx \&Fo
   scope is closed by
   .Sx \&Fc .
   .Pp
   See also
   .Sx MANUAL STRUCTURE ,
   .Sx \&Fa ,
   .Sx \&Fc ,
   and
   .Sx \&Ft .
 .Ss \&Fr  .Ss \&Fr
   This macro is obsolete and not implemented in
   .Xr mandoc 1 .
   .Pp
   It was used to show function return values.
   The syntax was:
   .Pp
   .Dl Pf . Sx \&Fr Ar value
 .Ss \&Ft  .Ss \&Ft
   A function type.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Ft Ar functype
   .Pp
   In the
   .Em SYNOPSIS
   section, a new output line is started after this macro.
   .Pp
   Examples:
   .Dl \&.Ft int
   .Bd -literal -offset indent -compact
   \&.Ft functype
   \&.Fn funcname
   .Ed
   .Pp
   See also
   .Sx MANUAL STRUCTURE ,
   .Sx \&Fn ,
   and
   .Sx \&Fo .
 .Ss \&Fx  .Ss \&Fx
 Format the FreeBSD version provided as an argument, or a default value  Format the
   .Fx
   version provided as an argument, or a default value
 if no argument is provided.  if no argument is provided.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Fx 7.1
 \&.Fx 7.1  .Dl \&.Fx
 \&.Fx  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Sx \&At ,
 .Sx \&Bx ,  
 .Sx \&Bsx ,  .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
 .Sx \&Nx ,  .Sx \&Nx ,
 .Sx \&Ox ,  .Sx \&Ox ,
 and  and
 .Sx \&Ux .  .Sx \&Ux .
 .  
 .Ss \&Hf  .Ss \&Hf
   This macro is not implemented in
   .Xr mandoc 1 .
   .Pp
   It was used to include the contents of a (header) file literally.
   The syntax was:
   .Pp
   .Dl Pf . Sx \&Hf Ar filename
 .Ss \&Ic  .Ss \&Ic
   Designate an internal or interactive command.
   This is similar to
   .Sx \&Cm
   but used for instructions rather than values.
   .Pp
   Examples:
   .Dl \&.Ic :wq
   .Dl \&.Ic hash
   .Dl \&.Ic alias
   .Pp
   Note that using
   .Sx \&Bd Fl literal
   or
   .Sx \&D1
   is preferred for displaying code; the
   .Sx \&Ic
   macro is used when referring to specific instructions.
 .Ss \&In  .Ss \&In
   An
   .Dq include
   file.
   When invoked as the first macro on an input line in the
   .Em SYNOPSIS
   section, the argument is displayed in angle brackets
   and preceded by
   .Dq #include ,
   and a blank line is inserted in front if there is a preceding
   function declaration.
   This is most often used in section 2, 3, and 9 manual pages.
   .Pp
   Examples:
   .Dl \&.In sys/types.h
   .Pp
   See also
   .Sx MANUAL STRUCTURE .
 .Ss \&It  .Ss \&It
   A list item.
   The syntax of this macro depends on the list type.
   .Pp
   Lists
   of type
   .Fl hang ,
   .Fl ohang ,
   .Fl inset ,
   and
   .Fl diag
   have the following syntax:
   .Pp
   .D1 Pf \. Sx \&It Ar args
   .Pp
   Lists of type
   .Fl bullet ,
   .Fl dash ,
   .Fl enum ,
   .Fl hyphen
   and
   .Fl item
   have the following syntax:
   .Pp
   .D1 Pf \. Sx \&It
   .Pp
   with subsequent lines interpreted within the scope of the
   .Sx \&It
   until either a closing
   .Sx \&El
   or another
   .Sx \&It .
   .Pp
   The
   .Fl tag
   list has the following syntax:
   .Pp
   .D1 Pf \. Sx \&It Op Cm args
   .Pp
   Subsequent lines are interpreted as with
   .Fl bullet
   and family.
   The line arguments correspond to the list's left-hand side; body
   arguments correspond to the list's contents.
   .Pp
   The
   .Fl column
   list is the most complicated.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&It Ar cell Op <TAB> Ar cell ...
   .D1 Pf \. Sx \&It Ar cell Op Sx \&Ta Ar cell ...
   .Pp
   The arguments consist of one or more lines of text and macros
   representing a complete table line.
   Cells within the line are delimited by tabs or by the special
   .Sx \&Ta
   block macro.
   The tab cell delimiter may only be used within the
   .Sx \&It
   line itself; on following lines, only the
   .Sx \&Ta
   macro can be used to delimit cells, and
   .Sx \&Ta
   is only recognized as a macro when called by other macros,
   not as the first macro on a line.
   .Pp
   Note that quoted strings may span tab-delimited cells on an
   .Sx \&It
   line.
   For example,
   .Pp
   .Dl .It \(dqcol1 ; <TAB> col2 ;\(dq \&;
   .Pp
   will preserve the semicolon whitespace except for the last.
   .Pp
   See also
   .Sx \&Bl .
 .Ss \&Lb  .Ss \&Lb
   Specify a library.
   The syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Lb Ar library
   .Pp
   The
   .Ar library
   parameter may be a system library, such as
   .Cm libz
   or
   .Cm libpam ,
   in which case a small library description is printed next to the linker
   invocation; or a custom library, in which case the library name is
   printed in quotes.
   This is most commonly used in the
   .Em SYNOPSIS
   section as described in
   .Sx MANUAL STRUCTURE .
   .Pp
   Examples:
   .Dl \&.Lb libz
   .Dl \&.Lb mdoc
 .Ss \&Li  .Ss \&Li
   Denotes text that should be in a
   .Li literal
   font mode.
   Note that this is a presentation term and should not be used for
   stylistically decorating technical terms.
   .Pp
   On terminal output devices, this is often indistinguishable from
   normal text.
   .Pp
   See also
   .Sx \&Bf ,
   .Sx \&Em ,
   .Sx \&No ,
   and
   .Sx \&Sy .
 .Ss \&Lk  .Ss \&Lk
   Format a hyperlink.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Lk Ar uri Op Ar name
   .Pp
   Examples:
   .Dl \&.Lk http://bsd.lv \*qThe BSD.lv Project\*q
   .Dl \&.Lk http://bsd.lv
   .Pp
   See also
   .Sx \&Mt .
 .Ss \&Lp  .Ss \&Lp
   Synonym for
   .Sx \&Pp .
 .Ss \&Ms  .Ss \&Ms
   Display a mathematical symbol.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Ms Ar symbol
   .Pp
   Examples:
   .Dl \&.Ms sigma
   .Dl \&.Ms aleph
 .Ss \&Mt  .Ss \&Mt
   Format a
   .Dq mailto:
   hyperlink.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Mt Ar address
   .Pp
   Examples:
   .Dl \&.Mt discuss@manpages.bsd.lv
 .Ss \&Nd  .Ss \&Nd
   A one line description of the manual's content.
   This may only be invoked in the
   .Em SYNOPSIS
   section subsequent the
   .Sx \&Nm
   macro.
   .Pp
   Examples:
   .Dl Pf . Sx \&Nd mdoc language reference
   .Dl Pf . Sx \&Nd format and display UNIX manuals
   .Pp
   The
   .Sx \&Nd
   macro technically accepts child macros and terminates with a subsequent
   .Sx \&Sh
   invocation.
   Do not assume this behaviour: some
   .Xr whatis 1
   database generators are not smart enough to parse more than the line
   arguments and will display macros verbatim.
   .Pp
   See also
   .Sx \&Nm .
 .Ss \&Nm  .Ss \&Nm
   The name of the manual page, or \(em in particular in section 1, 6,
   and 8 pages \(em of an additional command or feature documented in
   the manual page.
   When first invoked, the
   .Sx \&Nm
   macro expects a single argument, the name of the manual page.
   Usually, the first invocation happens in the
   .Em NAME
   section of the page.
   The specified name will be remembered and used whenever the macro is
   called again without arguments later in the page.
   The
   .Sx \&Nm
   macro uses
   .Sx Block full-implicit
   semantics when invoked as the first macro on an input line in the
   .Em SYNOPSIS
   section; otherwise, it uses ordinary
   .Sx In-line
   semantics.
   .Pp
   Examples:
   .Bd -literal -offset indent
   \&.Sh SYNOPSIS
   \&.Nm cat
   \&.Op Fl benstuv
   \&.Op Ar
   .Ed
   .Pp
   In the
   .Em SYNOPSIS
   of section 2, 3 and 9 manual pages, use the
   .Sx \&Fn
   macro rather than
   .Sx \&Nm
   to mark up the name of the manual page.
 .Ss \&No  .Ss \&No
   Normal text.
   Closes the scope of any preceding in-line macro.
   When used after physical formatting macros like
   .Sx \&Em
   or
   .Sx \&Sy ,
   switches back to the standard font face and weight.
   Can also be used to embed plain text strings in macro lines
   using semantic annotation macros.
   .Pp
   Examples:
   .Dl ".Em italic , Sy bold , No and roman"
   .Pp
   .Bd -literal -offset indent -compact
   \&.Sm off
   \&.Cm :C No / Ar pattern No / Ar replacement No /
   \&.Sm on
   .Ed
   .Pp
   See also
   .Sx \&Em ,
   .Sx \&Li ,
   and
   .Sx \&Sy .
 .Ss \&Ns  .Ss \&Ns
   Suppress a space between the output of the preceding macro
   and the following text or macro.
   Following invocation, input is interpreted as normal text
   just like after an
   .Sx \&No
   macro.
   .Pp
   This has no effect when invoked at the start of a macro line.
   .Pp
   Examples:
   .Dl ".Ar name Ns = Ns Ar value"
   .Dl ".Cm :M Ns Ar pattern"
   .Dl ".Fl o Ns Ar output"
   .Pp
   See also
   .Sx \&No
   and
   .Sx \&Sm .
 .Ss \&Nx  .Ss \&Nx
 Format the NetBSD version provided as an argument, or a default value if  Format the
   .Nx
   version provided as an argument, or a default value if
 no argument is provided.  no argument is provided.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Nx 5.01
 \&.Nx 5.01  .Dl \&.Nx
 \&.Nx  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Sx \&At ,
 .Sx \&Bx ,  
 .Sx \&Bsx ,  .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
 .Sx \&Fx ,  .Sx \&Fx ,
 .Sx \&Ox ,  .Sx \&Ox ,
 and  and
 .Sx \&Ux .  .Sx \&Ux .
 .  
 .Ss \&Oc  .Ss \&Oc
   Close multi-line
   .Sx \&Oo
   context.
 .Ss \&Oo  .Ss \&Oo
   Multi-line version of
   .Sx \&Op .
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Oo
   \&.Op Fl flag Ns Ar value
   \&.Oc
   .Ed
 .Ss \&Op  .Ss \&Op
   Optional part of a command line.
   Prints the argument(s) in brackets.
   This is most often used in the
   .Em SYNOPSIS
   section of section 1 and 8 manual pages.
   .Pp
   Examples:
   .Dl \&.Op \&Fl a \&Ar b
   .Dl \&.Op \&Ar a | b
   .Pp
   See also
   .Sx \&Oo .
 .Ss \&Os  .Ss \&Os
   Document operating system version.
   This is the mandatory third macro of
   any
   .Nm
   file.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Os Op Ar system Op Ar version
   .Pp
   The optional
   .Ar system
   parameter specifies the relevant operating system or environment.
   Left unspecified, it defaults to the local operating system version.
   This is the suggested form.
   .Pp
   Examples:
   .Dl \&.Os
   .Dl \&.Os KTH/CSC/TCS
   .Dl \&.Os BSD 4.3
   .Pp
   See also
   .Sx \&Dd
   and
   .Sx \&Dt .
 .Ss \&Ot  .Ss \&Ot
   This macro is obsolete and not implemented in
   .Xr mandoc 1 .
   .Pp
   Historical
   .Xr mdoc 7
   packages described it as
   .Dq "old function type (FORTRAN)" .
 .Ss \&Ox  .Ss \&Ox
 Format the OpenBSD version provided as an argument, or a default value  Format the
   .Ox
   version provided as an argument, or a default value
 if no argument is provided.  if no argument is provided.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Ox 4.5
 \&.Ox 4.5  .Dl \&.Ox
 \&.Ox  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Sx \&At ,
 .Sx \&Bsx ,  .Sx \&Bsx ,
 .Sx \&Bx ,  .Sx \&Bx ,
   .Sx \&Dx ,
 .Sx \&Fx ,  .Sx \&Fx ,
 .Sx \&Nx ,  .Sx \&Nx ,
 and  and
 .Sx \&Ux .  .Sx \&Ux .
 .  
 .Ss \&Pa  .Ss \&Pa
   An absolute or relative file system path, or a file or directory name.
   If an argument is not provided, the character
   .Sq \(ti
   is used as a default.
   .Pp
   Examples:
   .Dl \&.Pa /usr/bin/mandoc
   .Dl \&.Pa /usr/share/man/man7/mdoc.7
   .Pp
   See also
   .Sx \&Lk .
 .Ss \&Pc  .Ss \&Pc
   Close parenthesised context opened by
   .Sx \&Po .
 .Ss \&Pf  .Ss \&Pf
   Removes the space between its argument
   .Pq Dq prefix
   and the following macro.
   Its syntax is as follows:
   .Pp
   .D1 .Pf Ar prefix macro arguments ...
   .Pp
   This is equivalent to:
   .Pp
   .D1 .No Ar prefix No \&Ns Ar macro arguments ...
   .Pp
   Examples:
   .Dl ".Pf $ Ar variable_name"
   .Dl ".Pf 0x Ar hex_digits"
   .Pp
   See also
   .Sx \&Ns
   and
   .Sx \&Sm .
 .Ss \&Po  .Ss \&Po
   Multi-line version of
   .Sx \&Pq .
 .Ss \&Pp  .Ss \&Pp
   Break a paragraph.
   This will assert vertical space between prior and subsequent macros
   and/or text.
   .Pp
   Paragraph breaks are not needed before or after
   .Sx \&Sh
   or
   .Sx \&Ss
   macros or before displays
   .Pq Sx \&Bd
   or lists
   .Pq Sx \&Bl
   unless the
   .Fl compact
   flag is given.
 .Ss \&Pq  .Ss \&Pq
   Parenthesised enclosure.
   .Pp
   See also
   .Sx \&Po .
 .Ss \&Qc  .Ss \&Qc
   Close quoted context opened by
   .Sx \&Qo .
 .Ss \&Ql  .Ss \&Ql
   Format a single-quoted literal.
   See also
   .Sx \&Qq
   and
   .Sx \&Sq .
 .Ss \&Qo  .Ss \&Qo
   Multi-line version of
   .Sx \&Qq .
 .Ss \&Qq  .Ss \&Qq
 .  Encloses its arguments in
   .Qq typewriter
   double-quotes.
   Consider using
   .Sx \&Dq .
   .Pp
   See also
   .Sx \&Dq ,
   .Sx \&Sq ,
   and
   .Sx \&Qo .
 .Ss \&Re  .Ss \&Re
 Closes a  Close an
 .Sx \&Rs  .Sx \&Rs
 block.  Does not have any tail arguments.  block.
 .  Does not have any tail arguments.
 .Ss \&Rs  .Ss \&Rs
 Begins a bibliographic  Begin a bibliographic
 .Pq Dq reference  .Pq Dq reference
 block.  Does not have any head arguments.  The block macro and may only  block.
 contain  Does not have any head arguments.
   The block macro may only contain
 .Sx \&%A ,  .Sx \&%A ,
 .Sx \&%B ,  .Sx \&%B ,
 .Sx \&%C ,  .Sx \&%C ,
Line 1133  contain
Line 2705  contain
 .Sx \&%Q ,  .Sx \&%Q ,
 .Sx \&%R ,  .Sx \&%R ,
 .Sx \&%T ,  .Sx \&%T ,
   .Sx \&%U ,
 and  and
 .Sx \&%V  .Sx \&%V
 child macros (at least one must be specified).  child macros (at least one must be specified).
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Bd -literal -offset indent -compact
 \&.Rs  \&.Rs
 \&.%A J. E. Hopcroft  \&.%A J. E. Hopcroft
 \&.%A J. D. Ullman  \&.%A J. D. Ullman
Line 1154  If an
Line 2727  If an
 block is used within a SEE ALSO section, a vertical space is asserted  block is used within a SEE ALSO section, a vertical space is asserted
 before the rendered output, else the block continues on the current  before the rendered output, else the block continues on the current
 line.  line.
 .  
 .Ss \&Rv  .Ss \&Rv
   Insert a standard sentence regarding a function call's return value of 0
   on success and \-1 on error, with the
   .Va errno
   libc global variable set on error.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Rv Fl std Op Ar function ...
   .Pp
   If
   .Ar function
   is not specified, the document's name set by
   .Sx \&Nm
   is used.
   Multiple
   .Ar function
   arguments are treated as separate functions.
   .Pp
   See also
   .Sx \&Ex .
 .Ss \&Sc  .Ss \&Sc
   Close single-quoted context opened by
   .Sx \&So .
 .Ss \&Sh  .Ss \&Sh
   Begin a new section.
   For a list of conventional manual sections, see
   .Sx MANUAL STRUCTURE .
   These sections should be used unless it's absolutely necessary that
   custom sections be used.
   .Pp
   Section names should be unique so that they may be keyed by
   .Sx \&Sx .
   Although this macro is parsed, it should not consist of child node or it
   may not be linked with
   .Sx \&Sx .
   .Pp
   See also
   .Sx \&Pp ,
   .Sx \&Ss ,
   and
   .Sx \&Sx .
 .Ss \&Sm  .Ss \&Sm
   Switches the spacing mode for output generated from macros.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Sm Cm on | off
   .Pp
   By default, spacing is
   .Cm on .
   When switched
   .Cm off ,
   no white space is inserted between macro arguments and between the
   output generated from adjacent macros, but text lines
   still get normal spacing between words and sentences.
 .Ss \&So  .Ss \&So
   Multi-line version of
   .Sx \&Sq .
 .Ss \&Sq  .Ss \&Sq
   Encloses its arguments in
   .Sq typewriter
   single-quotes.
   .Pp
   See also
   .Sx \&Dq ,
   .Sx \&Qq ,
   and
   .Sx \&So .
 .Ss \&Ss  .Ss \&Ss
   Begin a new subsection.
   Unlike with
   .Sx \&Sh ,
   there is no convention for the naming of subsections.
   Except
   .Em DESCRIPTION ,
   the conventional sections described in
   .Sx MANUAL STRUCTURE
   rarely have subsections.
   .Pp
   Sub-section names should be unique so that they may be keyed by
   .Sx \&Sx .
   Although this macro is parsed, it should not consist of child node or it
   may not be linked with
   .Sx \&Sx .
   .Pp
   See also
   .Sx \&Pp ,
   .Sx \&Sh ,
   and
   .Sx \&Sx .
 .Ss \&St  .Ss \&St
   Replace an abbreviation for a standard with the full form.
   The following standards are recognised:
   .Pp
   .Bl -tag -width "-p1003.1g-2000X" -compact
   .It \-p1003.1-88
   .St -p1003.1-88
   .It \-p1003.1-90
   .St -p1003.1-90
   .It \-p1003.1-96
   .St -p1003.1-96
   .It \-p1003.1-2001
   .St -p1003.1-2001
   .It \-p1003.1-2004
   .St -p1003.1-2004
   .It \-p1003.1-2008
   .St -p1003.1-2008
   .It \-p1003.1
   .St -p1003.1
   .It \-p1003.1b
   .St -p1003.1b
   .It \-p1003.1b-93
   .St -p1003.1b-93
   .It \-p1003.1c-95
   .St -p1003.1c-95
   .It \-p1003.1g-2000
   .St -p1003.1g-2000
   .It \-p1003.1i-95
   .St -p1003.1i-95
   .It \-p1003.2-92
   .St -p1003.2-92
   .It \-p1003.2a-92
   .St -p1003.2a-92
   .It \-p1387.2-95
   .St -p1387.2-95
   .It \-p1003.2
   .St -p1003.2
   .It \-p1387.2
   .St -p1387.2
   .It \-isoC
   .St -isoC
   .It \-isoC-90
   .St -isoC-90
   .It \-isoC-amd1
   .St -isoC-amd1
   .It \-isoC-tcor1
   .St -isoC-tcor1
   .It \-isoC-tcor2
   .St -isoC-tcor2
   .It \-isoC-99
   .St -isoC-99
   .It \-iso9945-1-90
   .St -iso9945-1-90
   .It \-iso9945-1-96
   .St -iso9945-1-96
   .It \-iso9945-2-93
   .St -iso9945-2-93
   .It \-ansiC
   .St -ansiC
   .It \-ansiC-89
   .St -ansiC-89
   .It \-ansiC-99
   .St -ansiC-99
   .It \-ieee754
   .St -ieee754
   .It \-iso8802-3
   .St -iso8802-3
   .It \-ieee1275-94
   .St -ieee1275-94
   .It \-xpg3
   .St -xpg3
   .It \-xpg4
   .St -xpg4
   .It \-xpg4.2
   .St -xpg4.2
   .It \-xpg4.3
   .St -xpg4.3
   .It \-xbd5
   .St -xbd5
   .It \-xcu5
   .St -xcu5
   .It \-xsh5
   .St -xsh5
   .It \-xns5
   .St -xns5
   .It \-xns5.2
   .St -xns5.2
   .It \-xns5.2d2.0
   .St -xns5.2d2.0
   .It \-xcurses4.2
   .St -xcurses4.2
   .It \-susv2
   .St -susv2
   .It \-susv3
   .St -susv3
   .It \-svid4
   .St -svid4
   .El
 .Ss \&Sx  .Ss \&Sx
   Reference a section or subsection in the same manual page.
   The referenced section or subsection name must be identical to the
   enclosed argument, including whitespace.
   .Pp
   Examples:
   .Dl \&.Sx MANUAL STRUCTURE
   .Pp
   See also
   .Sx \&Sh
   and
   .Sx \&Ss .
 .Ss \&Sy  .Ss \&Sy
   Format enclosed arguments in symbolic
   .Pq Dq boldface .
   Note that this is a presentation term and should not be used for
   stylistically decorating technical terms.
   .Pp
   See also
   .Sx \&Bf ,
   .Sx \&Em ,
   .Sx \&Li ,
   and
   .Sx \&No .
   .Ss \&Ta
   Table cell separator in
   .Sx \&Bl Fl column
   lists; can only be used below
   .Sx \&It .
 .Ss \&Tn  .Ss \&Tn
   Format a tradename.
   .Pp
   Since this macro is often implemented to use a small caps font,
   it has historically been used for acronyms (like ASCII) as well.
   Such usage is not recommended because it would use the same macro
   sometimes for semantical annotation, sometimes for physical formatting.
   .Pp
   Examples:
   .Dl \&.Tn IBM
 .Ss \&Ud  .Ss \&Ud
   Prints out
   .Dq currently under development.
 .Ss \&Ux  .Ss \&Ux
 Format the UNIX name.  Accepts no argument.  Format the UNIX name.
   Accepts no argument.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Ux
 \&.Ux  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Sx \&At ,
 .Sx \&Bx ,  
 .Sx \&Bsx ,  .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
 .Sx \&Fx ,  .Sx \&Fx ,
 .Sx \&Nx ,  .Sx \&Nx ,
 and  and
 .Sx \&Ox .  .Sx \&Ox .
 .  
 .Ss \&Va  .Ss \&Va
   A variable name.
   .Pp
   Examples:
   .Dl \&.Va foo
   .Dl \&.Va const char *bar ;
 .Ss \&Vt  .Ss \&Vt
   A variable type.
   This is also used for indicating global variables in the
   .Em SYNOPSIS
   section, in which case a variable name is also specified.
   Note that it accepts
   .Sx Block partial-implicit
   syntax when invoked as the first macro on an input line in the
   .Em SYNOPSIS
   section, else it accepts ordinary
   .Sx In-line
   syntax.
   In the former case, this macro starts a new output line,
   and a blank line is inserted in front if there is a preceding
   function definition or include directive.
   .Pp
   Note that this should not be confused with
   .Sx \&Ft ,
   which is used for function return types.
   .Pp
   Examples:
   .Dl \&.Vt unsigned char
   .Dl \&.Vt extern const char * const sys_signame[] \&;
   .Pp
   See also
   .Sx MANUAL STRUCTURE
   and
   .Sx \&Va .
 .Ss \&Xc  .Ss \&Xc
   Close a scope opened by
   .Sx \&Xo .
 .Ss \&Xo  .Ss \&Xo
   Extend the header of an
   .Sx \&It
   macro or the body of a partial-implicit block macro
   beyond the end of the input line.
   This macro originally existed to work around the 9-argument limit
   of historic
   .Xr roff 7 .
 .Ss \&Xr  .Ss \&Xr
   Link to another manual
   .Pq Qq cross-reference .
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&Xr Ar name section
   .Pp
   The
   .Ar name
   and
   .Ar section
   are the name and section of the linked manual.
   If
   .Ar section
   is followed by non-punctuation, an
   .Sx \&Ns
   is inserted into the token stream.
   This behaviour is for compatibility with
   GNU troff.
   .Pp
   Examples:
   .Dl \&.Xr mandoc 1
   .Dl \&.Xr mandoc 1 \&;
   .Dl \&.Xr mandoc 1 \&Ns s behaviour
 .Ss \&br  .Ss \&br
   Emits a line-break.
   This macro should not be used; it is implemented for compatibility with
   historical manuals.
   .Pp
   Consider using
   .Sx \&Pp
   in the event of natural paragraph breaks.
 .Ss \&sp  .Ss \&sp
 .  Emits vertical space.
 .  This macro should not be used; it is implemented for compatibility with
   historical manuals.
   Its syntax is as follows:
   .Pp
   .D1 Pf \. Sx \&sp Op Ar height
   .Pp
   The
   .Ar height
   argument must be formatted as described in
   .Sx Scaling Widths .
   If unspecified,
   .Sx \&sp
   asserts a single vertical space.
 .Sh COMPATIBILITY  .Sh COMPATIBILITY
 This section documents compatibility with other roff implementations, at  This section documents compatibility between mandoc and other other
 this time limited to  troff implementations, at this time limited to GNU troff
 .Xr groff 1 .  .Pq Qq groff .
 The term  The term
 .Qq historic groff  .Qq historic groff
 refers to those versions before the  refers to groff versions before 1.17,
   which featured a significant update of the
 .Pa doc.tmac  .Pa doc.tmac
 file re-write  file.
 .Pq somewhere between 1.15 and 1.19 .  
 .  
 .Pp  .Pp
   Heirloom troff, the other significant troff implementation accepting
   \-mdoc, is similar to historic groff.
   .Pp
   The following problematic behaviour is found in groff:
   .ds hist (Historic groff only.)
   .Pp
 .Bl -dash -compact  .Bl -dash -compact
 .It  .It
 Negative scaling units are now truncated to zero instead of creating  Display macros
 interesting conditions, such as with  .Po
 .Sq \&sp -1i .  .Sx \&Bd ,
 Furthermore, the  .Sx \&Dl ,
 .Sq f  and
 scaling unit, while accepted, is rendered as the default unit.  .Sx \&D1
   .Pc
   may not be nested.
   \*[hist]
 .It  .It
 In quoted literals, groff allowed pair-wise double-quotes to produce a  .Sx \&At
 standalone double-quote in formatted output.  This idiosyncratic  with unknown arguments produces no output at all.
 behaviour is no longer applicable.  \*[hist]
   Newer groff and mandoc print
   .Qq AT&T UNIX
   and the arguments.
 .It  .It
 Display types  .Sx \&Bl Fl column
 .Sx \&Bd Fl center  does not recognize trailing punctuation characters when they immediately
 and  precede tabulator characters, but treats them as normal text and
 .Fl right  outputs a space before them.
 are aliases for  
 .Fl left .  
 The  
 .Fl file Ar file  
 argument is ignored.  Since text is not right-justified,  
 .Fl ragged  
 and  
 .Fl filled  
 are aliases, as are  
 .Fl literal  
 and  
 .Fl unfilled .  
 .It  .It
 Blocks of whitespace are stripped from both macro and free-form text  .Sx \&Bd Fl ragged compact
 lines (except when in literal mode), while groff would retain whitespace  does not start a new line.
 in free-form text lines.  \*[hist]
 .It  .It
 Historic groff has many un-callable macros.  Most of these (excluding  .Sx \&Dd
 some block-level macros) are now callable, conforming to the  with non-standard arguments behaves very strangely.
 non-historic groff version.  When there are three arguments, they are printed verbatim.
   Any other number of arguments is replaced by the current date,
   but without any arguments the string
   .Dq Epoch
   is printed.
 .It  .It
 The vertical bar  .Sx \&Fl
 .Sq \(ba  does not print a dash for an empty argument.
 made historic groff  \*[hist]
 .Qq go orbital  
 but is a proper delimiter in this implementation.  
 .It  .It
 .Sx \&It Fl nested  .Sx \&Fn
 is assumed for all lists (it wasn't in historic groff): any list may be  does not start a new line unless invoked as the line macro in the
 nested and  .Em SYNOPSIS
   section.
   \*[hist]
   .It
   .Sx \&Fo
   with
   .Pf non- Sx \&Fa
   children causes inconsistent spacing between arguments.
   In mandoc, a single space is always inserted between arguments.
   .It
   .Sx \&Ft
   in the
   .Em SYNOPSIS
   causes inconsistent vertical spacing, depending on whether a prior
   .Sx \&Fn
   has been invoked.
   See
   .Sx \&Ft
   and
   .Sx \&Fn
   for the normalised behaviour in mandoc.
   .It
   .Sx \&In
   ignores additional arguments and is not treated specially in the
   .Em SYNOPSIS .
   \*[hist]
   .It
   .Sx \&It
   sometimes requires a
   .Fl nested
   flag.
   \*[hist]
   In new groff and mandoc, any list may be nested by default and
 .Fl enum  .Fl enum
 lists will restart the sequence only for the sub-list.  lists will restart the sequence only for the sub-list.
 .It  .It
 Some manuals use  
 .Sx \&Li  .Sx \&Li
 incorrectly by following it with a reserved character and expecting the  followed by a delimiter is incorrectly used in some manuals
 delimiter to render.  This is not supported.  instead of properly quoting that character, which sometimes works with
   historic groff.
 .It  .It
 In groff, the  .Sx \&Lk
 .Sx \&Fo  only accepts a single link-name argument; the remainder is misformatted.
 macro only produces the first parameter.  This is no longer the case.  .It
   .Sx \&Pa
   does not format its arguments when used in the FILES section under
   certain list types.
   .It
   .Sx \&Ta
   can only be called by other macros, but not at the beginning of a line.
   .It
   .Sx \&%C
   is not implemented.
   .It
   Historic groff only allows up to eight or nine arguments per macro input
   line, depending on the exact situation.
   Providing more arguments causes garbled output.
   The number of arguments on one input line is not limited with mandoc.
   .It
   Historic groff has many un-callable macros.
   Most of these (excluding some block-level macros) are callable
   in new groff and mandoc.
   .It
   .Sq \(ba
   (vertical bar) is not fully supported as a delimiter.
   \*[hist]
   .It
   .Sq \ef
   .Pq font face
   and
   .Sq \ef
   .Pq font family face
   .Sx Text Decoration
   escapes behave irregularly when specified within line-macro scopes.
   .It
   Negative scaling units return to prior lines.
   Instead, mandoc truncates them to zero.
 .El  .El
 .  .Pp
 .  The following features are unimplemented in mandoc:
   .Pp
   .Bl -dash -compact
   .It
   .Sx \&Bd
   .Fl file Ar file .
   .It
   .Sx \&Bd
   .Fl offset Ar center
   and
   .Fl offset Ar right .
   Groff does not implement centered and flush-right rendering either,
   but produces large indentations.
   .It
   The
   .Sq \eh
   .Pq horizontal position ,
   .Sq \ev
   .Pq vertical position ,
   .Sq \em
   .Pq text colour ,
   .Sq \eM
   .Pq text filling colour ,
   .Sq \ez
   .Pq zero-length character ,
   .Sq \ew
   .Pq string length ,
   .Sq \ek
   .Pq horizontal position marker ,
   .Sq \eo
   .Pq text overstrike ,
   and
   .Sq \es
   .Pq text size
   escape sequences are all discarded in mandoc.
   .It
   The
   .Sq \ef
   scaling unit is accepted by mandoc, but rendered as the default unit.
   .It
   In quoted literals, groff allows pairwise double-quotes to produce a
   standalone double-quote in formatted output.
   This is not supported by mandoc.
   .El
 .Sh SEE ALSO  .Sh SEE ALSO
   .Xr man 1 ,
 .Xr mandoc 1 ,  .Xr mandoc 1 ,
 .Xr mandoc_char 7  .Xr eqn 7 ,
 .  .Xr man 7 ,
 .  .Xr mandoc_char 7 ,
   .Xr roff 7 ,
   .Xr tbl 7
   .Sh HISTORY
   The
   .Nm
   language first appeared as a troff macro package in
   .Bx 4.4 .
   It was later significantly updated by Werner Lemberg and Ruslan Ermilov
   in groff-1.17.
   The standalone implementation that is part of the
   .Xr mandoc 1
   utility written by Kristaps Dzonsons appeared in
   .Ox 4.6 .
 .Sh AUTHORS  .Sh AUTHORS
 The  The
 .Nm  .Nm
 reference was written by  reference was written by
 .An Kristaps Dzonsons Aq kristaps@kth.se .  .An Kristaps Dzonsons Aq kristaps@bsd.lv .
 .\"  
 .\" XXX: this really isn't the place for these caveats.  
 .\" .  
 .\" .  
 .\" .Sh CAVEATS  
 .\" There are many ambiguous parts of mdoc.  
 .\" .  
 .\" .Pp  
 .\" .Bl -dash -compact  
 .\" .It  
 .\" .Sq \&Fa  
 .\" should be  
 .\" .Sq \&Va  
 .\" as function arguments are variables.  
 .\" .It  
 .\" .Sq \&Ft  
 .\" should be  
 .\" .Sq \&Vt  
 .\" as function return types are still types.  Furthermore, the  
 .\" .Sq \&Ft  
 .\" should be removed and  
 .\" .Sq \&Fo ,  
 .\" which ostensibly follows it, should follow the same convention as  
 .\" .Sq \&Va .  
 .\" .It  
 .\" .Sq \&Va  
 .\" should formalise that only one or two arguments are acceptable: a  
 .\" variable name and optional, preceding type.  
 .\" .It  
 .\" .Sq \&Fd  
 .\" is ambiguous.  It's commonly used to indicate an include file in the  
 .\" synopsis section.  
 .\" .Sq \&In  
 .\" should be used, instead.  
 .\" .It  
 .\" Only the  
 .\" .Sq \-literal  
 .\" argument to  
 .\" .Sq \&Bd  
 .\" makes sense.  The remaining ones should be removed.  
 .\" .It  
 .\" The  
 .\" .Sq \&Xo  
 .\" and  
 .\" .Sq \&Xc  
 .\" macros should be deprecated.  
 .\" .It  
 .\" The  
 .\" .Sq \&Dt  
 .\" macro lacks clarity.  It should be absolutely clear which title will  
 .\" render when formatting the manual page.  
 .\" .It  
 .\" A  
 .\" .Sq \&Lx  
 .\" should be provided for Linux (\(`a la  
 .\" .Sq \&Ox ,  
 .\" .Sq \&Nx  
 .\" etc.).  
 .\" .It  
 .\" There's no way to refer to references in  
 .\" .Sq \&Rs/Re  
 .\" blocks.  
 .\" .It  
 .\" The \-split and \-nosplit dictates via  
 .\" .Sq \&An  
 .\" are re-set when entering and leaving the AUTHORS section.  
 .\" .El  
 .\" .  
Legend:
Removed from v.1.65  
changed lines
  Added in v.1.201
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