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version 1.88, 2010/04/06 07:17:51 version 1.279, 2019/07/15 19:20:30
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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, 2011, 2013-2018 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 semantic markup language for formatting manual pages
 .  
 .  
 .Sh DESCRIPTION  .Sh DESCRIPTION
 The  The
 .Nm mdoc  .Nm mdoc
 language is used to format  language supports authoring of manual pages for the
 .Bx  .Xr man 1
 .Ux  utility by allowing semantic annotations of words, phrases,
 manuals.  In this reference document, we describe its syntax, structure,  page sections and complete manual pages.
 and usage.  Our reference implementation is  Such annotations are used by formatting tools to achieve a uniform
 .Xr mandoc 1 .  presentation across all manuals written in
 The  .Nm ,
   and to support hyperlinking if supported by the output medium.
   .Pp
   This reference document describes the structure of manual pages
   and the syntax and usage of the
   .Nm
   language.
   The reference implementation of a parsing and formatting tool 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  In an
 .Nm  .Nm
 document follows simple rules:  lines beginning with the control  document, lines beginning with the control character
 character  .Sq \&.
 .Sq \.  are called
 are parsed for macros.  Other lines are interpreted within the scope of  .Dq macro lines .
 prior macros:  The first word is the macro name.
   It consists of two or three letters.
   Most macro names begin with a capital letter.
   For a list of available macros, see
   .Sx MACRO OVERVIEW .
   The words following the macro name are arguments to the macro, optionally
   including the names of other, callable macros; see
   .Sx MACRO SYNTAX
   for details.
   .Pp
   Lines not beginning with the control character are called
   .Dq text lines .
   They provide free-form text to be printed; the formatting of the text
   depends on the respective processing context:
 .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  
 .Nm  
 documents may contain only graphable 7-bit ASCII characters, the space  
 character, and, in certain circumstances, the tab character.  All  
 manuals must have  
 .Ux  
 line terminators.  
 .  
 .  
 .Ss Comments  
 Text following a  
 .Sq \e" ,  
 whether in a macro or free-form text line, is ignored to the end of  
 line.  A macro line with only a control character and comment escape,  
 .Sq \&.\e" ,  
 is also ignored.  Macro lines with only a control charater and optionally  
 whitespace are stripped from input.  
 .  
 .  
 .Ss Reserved Characters  
 Within a macro line, the following characters are reserved:  
 .Pp  .Pp
 .Bl -tag -width Ds -offset indent -compact  Many aspects of the basic syntax of the
 .It \&.  .Nm
 .Pq period  language are based on the
 .It \&,  .Xr roff 7
 .Pq comma  language; see the
 .It \&:  .Em LANGUAGE SYNTAX
 .Pq colon  
 .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  
 Special characters may occur in both macro and free-form lines.  
 Sequences begin with the escape character  
 .Sq \e  
 followed by either an open-parenthesis  
 .Sq \&(  
 for two-character sequences; an open-bracket  
 .Sq \&[  
 for n-character sequences (terminated at a close-bracket  
 .Sq \&] ) ;  
 or a single one-character sequence.  See  
 .Xr mandoc_char 7  
 for a complete list.  Examples include  
 .Sq \e(em  
 .Pq em-dash  
 and  and
 .Sq \ee  .Em MACRO SYNTAX
 .Pq back-slash .  sections in the
 .  .Xr roff 7
 .  manual for details, in particular regarding
 .Ss Text Decoration  comments, escape sequences, whitespace, and quoting.
 Terms may be text-decorated using the  However, using
 .Sq \ef  .Xr roff 7
 escape followed by an indicator: B (bold), I, (italic), R (Roman), or P  requests in
 (revert to previous mode):  
 .Pp  
 .D1 \efBbold\efR \efIitalic\efP  
 .Pp  
 A numerical representation 3, 2, or 1 (bold, italic, and Roman,  
 respectively) may be used instead.  A text decoration is valid within  
 the current font scope only:  if a macro opens a font scope alongside  
 its own scope, such as  
 .Sx \&Bf  
 .Cm \&Sy ,  
 in-scope invocations of  
 .Sq \ef  
 are only valid within the font scope of the macro.  If  
 .Sq \ef  
 is specified outside of any font scope, such as in unenclosed, free-form  
 text, it will affect the remainder of the document.  
 .Pp  
 Text may also be sized with the  
 .Sq \es  
 escape, whose syntax is one of  
 .Sq \es+-n  
 for one-digit numerals;  
 .Sq \es(+-nn  
 or  
 .Sq \es+-(nn  
 for two-digit numerals; and  
 .Sq \es[+-N] ,  
 .Sq \es+-[N] ,  
 .Sq \es'+-N' ,  
 or  
 .Sq \es+-'N'  
 for arbitrary-digit numerals:  
 .Pp  
 .D1 \es+1bigger\es-1  
 .D1 \es[+10]much bigger\es[-10]  
 .D1 \es+(10much bigger\es-(10  
 .D1 \es+'100'much much bigger\es-'100'  
 .Pp  
 Note these forms are  
 .Em not  
 recommended for  
 .Nm ,  
 which encourages semantic annotation.  
 .  
 .  
 .Ss Predefined Strings  
 Historically,  
 .Xr groff 1  
 also defined a set of package-specific  
 .Dq predefined strings ,  
 which, like  
 .Sx Special Characters ,  
 demark special output characters and strings by way of input codes.  
 Predefined strings are escaped with the slash-asterisk,  
 .Sq \e* :  
 single-character  
 .Sq \e*X ,  
 two-character  
 .Sq \e*(XX ,  
 and N-character  
 .Sq \e*[N] .  
 See  
 .Xr mandoc_char 7  
 for a complete list.  Examples include  
 .Sq \e*(Am  
 .Pq ampersand  
 and  
 .Sq \e*(Ba  
 .Pq vertical bar .  
 .  
 .  
 .Ss Whitespace  
 In non-literal free-form lines, consecutive blocks of whitespace are  
 pruned from input and added later in the output filter, if applicable:  
 .Bd -literal -offset indent  
 These     spaces   are    pruned       from    input.  
 \&.Bd \-literal  
 These         are              not.  
 \&.Ed  
 .Ed  
 .  
 .Pp  
 In macro lines, whitespace delimits arguments and is discarded.  If  
 arguments are quoted, whitespace within the quotes is retained.  
 .  
 .Pp  
 Blank lines are only permitted within literal contexts, as are lines  
 containing only whitespace.  Tab characters are only acceptable when  
 delimiting  
 .Sq \&Bl \-column  
 or when in a literal context.  
 .  
 .  
 .Ss Quotation  
 Macro arguments may be quoted with a double-quote to group  
 space-delimited terms or to retain blocks of whitespace.  A quoted  
 argument begins with a double-quote preceded by whitespace.  The next  
 double-quote not pair-wise adjacent to another double-quote terminates  
 the literal, regardless of surrounding whitespace.  
 .  
 .Pp  
 This produces tokens  
 .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  
 In free-form mode, quotes are regarded as opaque text.  
 .  
 .Ss Dates  
 There are several macros in  
 .Nm  .Nm
 that require a date argument.  The canonical form for dates is the  documents is discouraged;
 American format:  .Xr mandoc 1
 .Pp  supports some of them merely for backward compatibility.
 .D1 Cm Month Day , Year  
 .Pp  
 The  
 .Cm Day  
 value is an optionally zero-padded numeral.  The  
 .Cm Month  
 value is the full month name.  The  
 .Cm Year  
 value is the full four-digit year.  
 .Pp  
 Reduced form dates are broken-down canonical form dates:  
 .Pp  
 .D1 Cm Month , Year  
 .D1 Cm Year  
 .Pp  
 Some examples of valid dates follow:  
 .Pp  
 .D1 "May, 2009" Pq reduced form  
 .D1 "2009" Pq reduced form  
 .D1 "May 20, 2009" Pq canonical form  
 .  
 .Ss Scaling Widths  
 Many macros support scaled widths for their arguments, such as  
 stipulating a two-inch list indentation with the following:  
 .Bd -literal -offset indent  
 \&.Bl -tag -width 2i  
 .Ed  
 .  
 .Pp  
 The syntax for scaled widths is  
 .Sq Li [+-]?[0-9]*.[0-9]*[:unit:] ,  
 where a decimal must be preceded or proceeded by at least one digit.  
 Negative numbers, while accepted, are truncated to zero.  The following  
 scaling units are accepted:  
 .Pp  
 .Bl -tag -width Ds -offset indent -compact  
 .It c  
 centimetre  
 .It i  
 inch  
 .It P  
 pica (~1/6 inch)  
 .It p  
 point (~1/72 inch)  
 .It f  
 synonym for  
 .Sq u  
 .It v  
 default vertical span  
 .It m  
 width of rendered  
 .Sq m  
 .Pq em  
 character  
 .It n  
 width of rendered  
 .Sq n  
 .Pq en  
 character  
 .It u  
 default horizontal span  
 .It M  
 mini-em (~1/100 em)  
 .El  
 .Pp  
 Using anything other than  
 .Sq m ,  
 .Sq n ,  
 .Sq u ,  
 or  
 .Sq v  
 is necessarily non-portable across output media.  See  
 .Sx COMPATIBILITY .  
 .  
 .  
 .Sh MANUAL STRUCTURE  .Sh MANUAL STRUCTURE
 A well-formed  A well-formed
 .Nm  .Nm
 document consists of a document prologue followed by one or more  document consists of a document prologue followed by one or more
 sections.  sections.
 .Pp  .Pp
 The prologue, which consists of (in order) the  The prologue, which consists of the
 .Sx \&Dd ,  .Ic \&Dd ,
 .Sx \&Dt ,  .Ic \&Dt ,
 and  and
 .Sx \&Os  .Ic \&Os
 macros, is required for every document.  macros in that order, is required for every document.
 .Pp  .Pp
 The first section (sections are denoted by  The first section (sections are denoted by
 .Sx \&Sh )  .Ic \&Sh )
 must be the NAME section, consisting of at least one  must be the NAME section, consisting of at least one
 .Sx \&Nm  .Ic \&Nm
 followed by  followed by
 .Sx \&Nd .  .Ic \&Nd .
 .Pp  .Pp
 Following that, convention dictates specifying at least the SYNOPSIS and  Following that, convention dictates specifying at least the
 DESCRIPTION sections, although this varies between manual sections.  .Em SYNOPSIS
   and
   .Em DESCRIPTION
   sections, although this varies between manual sections.
 .Pp  .Pp
 The following is a well-formed skeleton  The following is a well-formed skeleton
 .Nm  .Nm
 file:  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\(dq .Sh LIBRARY
 \&.\e\*q .Sh LIBRARY  \&.\e\(dq For sections 2, 3, and 9 only.
 \&.  \&.\e\(dq 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\(dq .Sh CONTEXT
 \&.\e\*q The next is for sections 1 & 8 only.  \&.\e\(dq For section 9 functions only.
 \&.\e\*q .Sh EXIT STATUS  \&.\e\(dq .Sh IMPLEMENTATION NOTES
 \&.\e\*q The next is for sections 2, 3, & 9 only.  \&.\e\(dq Not used in OpenBSD.
 \&.\e\*q .Sh RETURN VALUES  \&.\e\(dq .Sh RETURN VALUES
 \&.\e\*q The next is for sections 1, 6, 7, & 8 only.  \&.\e\(dq For sections 2, 3, and 9 function return values only.
 \&.\e\*q .Sh ENVIRONMENT  \&.\e\(dq .Sh ENVIRONMENT
 \&.\e\*q .Sh FILES  \&.\e\(dq For sections 1, 6, 7, and 8 only.
 \&.\e\*q .Sh EXAMPLES  \&.\e\(dq .Sh FILES
 \&.\e\*q The next is for sections 1, 4, 6, 7, & 8 only.  \&.\e\(dq .Sh EXIT STATUS
 \&.\e\*q .Sh DIAGNOSTICS  \&.\e\(dq For sections 1, 6, and 8 only.
 \&.\e\*q The next is for sections 2, 3, & 9 only.  \&.\e\(dq .Sh EXAMPLES
 \&.\e\*q .Sh ERRORS  \&.\e\(dq .Sh DIAGNOSTICS
 \&.\e\*q .Sh SEE ALSO  \&.\e\(dq For sections 1, 4, 6, 7, 8, and 9 printf/stderr messages only.
 \&.\e\*q .Xr foobar 1  \&.\e\(dq .Sh ERRORS
 \&.\e\*q .Sh STANDARDS  \&.\e\(dq For sections 2, 3, 4, and 9 errno settings only.
 \&.\e\*q .Sh HISTORY  \&.\e\(dq .Sh SEE ALSO
 \&.\e\*q .Sh AUTHORS  \&.\e\(dq .Xr foobar 1
 \&.\e\*q .Sh CAVEATS  \&.\e\(dq .Sh STANDARDS
 \&.\e\*q .Sh BUGS  \&.\e\(dq .Sh HISTORY
 \&.\e\*q .Sh SECURITY CONSIDERATIONS  \&.\e\(dq .Sh AUTHORS
   \&.\e\(dq .Sh CAVEATS
   \&.\e\(dq .Sh BUGS
   \&.\e\(dq .Sh SECURITY CONSIDERATIONS
   \&.\e\(dq Not used in OpenBSD.
 .Ed  .Ed
 .Pp  .Pp
 The sections in a  The sections in an
 .Nm  .Nm
 document are conventionally ordered as they appear above.  Sections  document are conventionally ordered as they appear above.
 should be composed as follows:  Sections should be composed as follows:
 .Bl -ohang -offset Ds  .Bl -ohang -offset Ds
 .It Em NAME  .It Em NAME
 The name(s) and a short description of the documented material.  The  The name(s) and a one line description of the documented material.
 syntax for this as follows:  The syntax for this as follows:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Nm name0  \&.Nm name0 ,
 \&.Nm name1  \&.Nm name1 ,
 \&.Nm name2  \&.Nm name2
 \&.Nd a short description  \&.Nd a one line description
 .Ed  .Ed
 .Pp  .Pp
   Multiple
   .Sq \&Nm
   names should be separated by commas.
   .Pp
 The  The
 .Sx \&Nm  .Ic \&Nm
 macro(s) must precede the  macro(s) must precede the
 .Sx \&Nd  .Ic \&Nd
 macro.  macro.
 .Pp  .Pp
 See  See
 .Sx \&Nm  .Ic \&Nm
 and  and
 .Sx \&Nd .  .Ic \&Nd .
 .  
 .It Em LIBRARY  .It Em LIBRARY
 The name of the library containing the documented material, which is  The name of the library containing the documented material, which is
 assumed to be a function in a section 2 or 3 manual.  The syntax for  assumed to be a function in a section 2, 3, or 9 manual.
 this is as follows:  The syntax for this is as follows:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Lb libarm  \&.Lb libarm
 .Ed  .Ed
 .Pp  .Pp
 See  See
 .Sx \&Lb .  .Ic \&Lb .
 .  
 .It Em SYNOPSIS  .It Em SYNOPSIS
 Documents the utility invocation syntax, function call syntax, or device  Documents the utility invocation syntax, function call syntax, or device
 configuration.  configuration.
Line 443  configuration.
Line 208  configuration.
 For the first, utilities (sections 1, 6, and 8), this is  For the first, utilities (sections 1, 6, and 8), this is
 generally structured as follows:  generally structured as follows:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Nm foo  \&.Nm bar
 \&.Op Fl v  \&.Op Fl v
 \&.Op Fl o Ar file  \&.Op Fl o Ar file
 \&.Op Ar  \&.Op Ar
 \&.Nm bar  \&.Nm foo
 \&.Op Fl v  \&.Op Fl v
 \&.Op Fl o Ar file  \&.Op Fl o Ar file
 \&.Op Ar  \&.Op Ar
 .Ed  .Ed
 .Pp  .Pp
   Commands should be ordered alphabetically.
   .Pp
 For the second, function calls (sections 2, 3, 9):  For the second, function calls (sections 2, 3, 9):
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Vt extern const char *global;  
 \&.In header.h  \&.In header.h
   \&.Vt extern const char *global;
 \&.Ft "char *"  \&.Ft "char *"
 \&.Fn foo "const char *src"  \&.Fn foo "const char *src"
 \&.Ft "char *"  \&.Ft "char *"
 \&.Fn bar "const char *src"  \&.Fn bar "const char *src"
 .Ed  .Ed
 .Pp  .Pp
   Ordering of
   .Ic \&In ,
   .Ic \&Vt ,
   .Ic \&Fn ,
   and
   .Ic \&Fo
   macros should follow C header-file conventions.
   .Pp
 And for the third, configurations (section 4):  And for the third, configurations (section 4):
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Cd \*qit* at isa? port 0x2e\*q  \&.Cd \(dqit* at isa? port 0x2e\(dq
 \&.Cd \*qit* at isa? port 0x4e\*q  \&.Cd \(dqit* at isa? port 0x4e\(dq
 .Ed  .Ed
 .Pp  .Pp
 Manuals not in these sections generally don't need a  Manuals not in these sections generally don't need a
 .Em SYNOPSIS .  .Em SYNOPSIS .
 .Pp  .Pp
 See  Some macros are displayed differently in the
 .Sx \&Op ,  .Em SYNOPSIS
 .Sx \&Cd ,  section, particularly
 .Sx \&Fn ,  .Ic \&Nm ,
 .Sx \&Ft ,  .Ic \&Cd ,
   .Ic \&Fd ,
   .Ic \&Fn ,
   .Ic \&Fo ,
   .Ic \&In ,
   .Ic \&Vt ,
 and  and
 .Sx \&Vt .  .Ic \&Ft .
 .  All of these macros are output on their own line.
   If two such dissimilar macros are pairwise invoked (except for
   .Ic \&Ft
   before
   .Ic \&Fo
   or
   .Ic \&Fn ) ,
   they are separated by a vertical space, unless in the case of
   .Ic \&Fo ,
   .Ic \&Fn ,
   and
   .Ic \&Ft ,
   which are always separated by vertical space.
   .Pp
   When text and macros following an
   .Ic \&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
   .Ic \&Nm
   macro, up to the next
   .Ic \&Nm ,
   .Ic \&Sh ,
   or
   .Ic \&Ss
   macro or the end of an enclosing block, whichever comes first.
 .It Em DESCRIPTION  .It Em DESCRIPTION
 This expands upon the brief, one-line description in  This begins with an expansion of the brief, one line description in
 .Em NAME .  .Em NAME :
 It usually contains a break-down of the options (if documenting a  .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:  command), such as:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 The arguments are as follows:  The arguments are as follows:
Line 493  Print verbose information.
Line 304  Print verbose information.
 \&.El  \&.El
 .Ed  .Ed
 .Pp  .Pp
   List the options in alphabetical order,
   uppercase before lowercase for each letter and
   with no regard to whether an option takes an argument.
   Put digits in ascending order before all letter options.
   .Pp
 Manuals not documenting a command won't include the above fragment.  Manuals not documenting a command won't include the above fragment.
 .  
 .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 EXIT STATUS  
 Command exit status for section 1, 6, and 8 manuals.  This section is  
 the dual of  
 .Em RETURN VALUES ,  
 which is used for functions.  Historically, this information was  
 described in  
 .Em DIAGNOSTICS ,  
 a practise that is now discouraged.  
 .Pp  .Pp
 See  Since the
 .Sx \&Ex .  .Em DESCRIPTION
 .  section usually contains most of the text of a manual, longer manuals
   often use the
   .Ic \&Ss
   macro to form subsections.
   In very long manuals, the
   .Em DESCRIPTION
   may be split into multiple sections, each started by an
   .Ic \&Sh
   macro followed by a non-standard section name, and each having
   several subsections, like in the present
   .Nm
   manual.
   .It Em CONTEXT
   This section lists the contexts in which functions can be called in section 9.
   The contexts are autoconf, process, or interrupt.
   .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  .It Em RETURN VALUES
 This section is the dual of  This section documents the
 .Em EXIT STATUS ,  return values of functions in sections 2, 3, and 9.
 which is used for commands.  It documents the return values of functions  
 in sections 2, 3, and 9.  
 .Pp  .Pp
 See  See
 .Sx \&Rv .  .Ic \&Rv .
 .  
 .It Em ENVIRONMENT  .It Em ENVIRONMENT
 Documents any usages of environment variables, e.g.,  Lists the environment variables used by the utility,
 .Xr environ 7 .  and explains the syntax and semantics of their values.
   The
   .Xr environ 7
   manual provides examples of typical content and formatting.
 .Pp  .Pp
 See  See
 .Sx \&Ev .  .Ic \&Ev .
 .  
 .It Em FILES  .It Em FILES
 Documents files used.  It's helpful to document both the file and a  Documents files used.
 short description of how the file is used (created, modified, etc.).  It's helpful to document both the file name and a short description of how
   the file is used (created, modified, etc.).
 .Pp  .Pp
 See  See
 .Sx \&Pa .  .Ic \&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
   .Ic \&Ex .
 .It Em EXAMPLES  .It Em EXAMPLES
 Example usages.  This often contains snippets of well-formed,  Example usages.
 well-tested invocations.  Make doubly sure that your examples work  This often contains snippets of well-formed, well-tested invocations.
 properly!  Make sure that examples work properly!
 .  
 .It Em DIAGNOSTICS  .It Em DIAGNOSTICS
 Documents error conditions.  This is most useful in section 4 manuals.  Documents error messages.
   In section 4 and 9 manuals, these are usually messages printed by the
   kernel to the console and to the kernel log.
   In section 1, 6, 7, and 8, these are usually messages printed by
   userland programs to the standard error output.
   .Pp
 Historically, this section was used in place of  Historically, this section was used in place of
 .Em EXIT STATUS  .Em EXIT STATUS
 for manuals in sections 1, 6, and 8; however, this practise is  for manuals in sections 1, 6, and 8; however, this practise is
 discouraged.  discouraged.
 .Pp  .Pp
 See  See
 .Sx \&Bl  .Ic \&Bl
 .Fl diag .  .Fl diag .
 .  
 .It Em ERRORS  .It Em ERRORS
 Documents error handling in sections 2, 3, and 9.  Documents
   .Xr errno 2
   settings in sections 2, 3, 4, and 9.
 .Pp  .Pp
 See  See
 .Sx \&Er .  .Ic \&Er .
 .  
 .It Em SEE ALSO  .It Em SEE ALSO
 References other manuals with related topics.  This section should exist  References other manuals with related topics.
 for most manuals.  Cross-references should conventionally be ordered  This section should exist for most manuals.
 first by section, then alphabetically.  Cross-references should conventionally be ordered first by section, then
   alphabetically (ignoring case).
 .Pp  .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  See
 .Sx \&Xr .  .Ic \&Rs
 .  and
   .Ic \&Xr .
 .It Em STANDARDS  .It Em STANDARDS
 References any standards implemented or used.  If not adhering to any  References any standards implemented or used.
 standards, the  If not adhering to any standards, the
 .Em HISTORY  .Em HISTORY
 section should be used instead.  section should be used instead.
 .Pp  .Pp
 See  See
 .Sx \&St .  .Ic \&St .
 .  
 .It Em HISTORY  .It Em HISTORY
 The history of any manual without a  A brief history of the subject, including where it was first implemented,
 .Em STANDARDS  and when it was ported to or reimplemented for the operating system at hand.
 section should be described in this section.  
 .  
 .It Em AUTHORS  .It Em AUTHORS
 Credits to authors, if applicable, should appear in this section.  Credits to the person or persons who wrote the code and/or documentation.
 Authors should generally be noted by both name and an e-mail address.  Authors should generally be noted by both name and email address.
 .Pp  .Pp
 See  See
 .Sx \&An .  .Ic \&An .
 .  
 .It Em CAVEATS  .It Em CAVEATS
 Explanations of common misuses and misunderstandings should be explained  Common misuses and misunderstandings should be explained
 in this section.  in this section.
 .  
 .It Em BUGS  .It Em BUGS
 Extant bugs should be described in this section.  Known bugs, limitations, and work-arounds should be described
 .  in this section.
 .It Em SECURITY CONSIDERATIONS  .It Em SECURITY CONSIDERATIONS
 Documents any security precautions that operators should consider.  Documents any security precautions that operators should consider.
 .  
 .El  .El
 .  .Sh MACRO OVERVIEW
 .  This overview is sorted such that macros of similar purpose are listed
 .Sh MACRO SYNTAX  together, to help find the best macro for any given purpose.
 Macros are one to three three characters in length and begin with a  Deprecated macros are not included in the overview, but can be found below
 control character ,  in the alphabetical
 .Sq \&. ,  .Sx MACRO REFERENCE .
 at the beginning of the line.  An arbitrary amount of whitespace may  .Ss Document preamble and NAME section macros
 sit between the control character and the macro name.  Thus, the  .Bl -column "Brq, Bro, Brc" description
 following are equivalent:  .It Ic \&Dd Ta document date: Cm $\&Mdocdate$ | Ar month day , year
 .Bd -literal -offset indent  .It Ic \&Dt Ta document title: Ar TITLE section Op Ar arch
 \&.Pp  .It Ic \&Os Ta operating system version: Op Ar system Op Ar version
 \&.\ \ \ \&Pp  .It Ic \&Nm Ta document name (one argument)
 .Ed  .It Ic \&Nd Ta document description (one line)
 .  
 .Pp  
 The syntax of a macro depends on its classification.  In this section,  
 .Sq \-arg  
 refers to macro arguments, which may be followed by zero or more  
 .Sq parm  
 parameters;  
 .Sq \&Yo  
 opens the scope of a macro; and if specified,  
 .Sq \&Yc  
 closes it out.  
 .  
 .Pp  
 The  
 .Em Callable  
 column indicates that the macro may be called subsequent to the initial  
 line-macro.  If a macro is not callable, then its invocation after the  
 initial line macro is interpreted as opaque text, such that  
 .Sq \&.Fl \&Sh  
 produces  
 .Sq Fl \&Sh .  
 .  
 .Pp  
 The  
 .Em Parsable  
 column indicates whether the macro may be followed by further  
 (ostensibly callable) macros.  If a macro is not parsable, subsequent  
 macro invocations on the line will be interpreted as opaque text.  
 .  
 .Pp  
 The  
 .Em Scope  
 column, if applicable, describes closure rules.  
 .  
 .  
 .Ss Block full-explicit  
 Multi-line scope closed by an explicit closing macro.  All macros  
 contains bodies; only  
 .Sx \&Bf  
 contains a head.  
 .Bd -literal -offset indent  
 \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB  
 \(lBbody...\(rB  
 \&.Yc  
 .Ed  
 .  
 .Pp  
 .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsableX" "closed by XXX"  
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  
 .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 \&Bk  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ek  
 .It Sx \&Bl  Ta    \&No     Ta    \&No     Ta    closed by Sx \&El  
 .It Sx \&Ed  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bd  
 .It Sx \&Ef  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bf  
 .It Sx \&Ek  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bk  
 .It Sx \&El  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bl  
 .El  .El
 .  .Ss Sections and cross references
 .  .Bl -column "Brq, Bro, Brc" description
 .Ss Block full-implicit  .It Ic \&Sh Ta section header (one line)
 Multi-line scope closed by end-of-file or implicitly by another macro.  .It Ic \&Ss Ta subsection header (one line)
 All macros have bodies; some  .It Ic \&Sx Ta internal cross reference to a section or subsection
 .Po  .It Ic \&Xr Ta cross reference to another manual page: Ar name section
 .Sx \&It Fl bullet ,  .It Ic \&Pp Ta start a text paragraph (no arguments)
 .Fl hyphen ,  
 .Fl dash ,  
 .Fl enum ,  
 .Fl item  
 .Pc  
 don't have heads; only one  
 .Po  
 .Sx \&It Fl column  
 .Pc  
 has multiple heads.  
 .Bd -literal -offset indent  
 \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead... \(lBTa head...\(rB\(rB  
 \(lBbody...\(rB  
 .Ed  
 .  
 .Pp  
 .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsableX" "closed by XXXXXXXXXXX"  
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  
 .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 \&Sh  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Sh  
 .It Sx \&Ss  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Sh , Sx \&Ss  
 .El  .El
 .  .Ss Displays and lists
 .  .Bl -column "Brq, Bro, Brc" description
 .Ss Block partial-explicit  .It Ic \&Bd , \&Ed Ta display block:
 Like block full-explicit, but also with single-line scope.  Each  .Fl Ar type
 has at least a body and, in limited circumstances, a head  .Op Fl offset Ar width
 .Po  .Op Fl compact
 .Sx \&Fo ,  .It Ic \&D1 Ta indented display (one line)
 .Sx \&Eo  .It Ic \&Dl Ta indented literal display (one line)
 .Pc  .It Ic \&Ql Ta in-line literal display: Ql text
 and/or tail  .It Ic \&Bl , \&El Ta list block:
 .Pq Sx \&Ec .  .Fl Ar type
 .Bd -literal -offset indent  .Op Fl width Ar val
 \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB  .Op Fl offset Ar val
 \(lBbody...\(rB  .Op Fl compact
 \&.Yc \(lBtail...\(rB  .It Ic \&It Ta list item (syntax depends on Fl Ar type )
   .It Ic \&Ta Ta table cell separator in Ic \&Bl Fl column No lists
 \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB \  .It Ic \&Rs , \&%* , \&Re Ta bibliographic block (references)
 \(lBbody...\(rB \&Yc \(lBtail...\(rB  
 .Ed  
 .  
 .Pp  
 .Bl -column "MacroX" "CallableX" "ParsableX" "closed by XXXX" -compact -offset indent  
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  
 .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 \&Bc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Bo  
 .It Sx \&Bo  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Bc  
 .It Sx \&Brc Ta    Yes      Ta    Yes      Ta    opened by Sx \&Bro  
 .It Sx \&Bro Ta    Yes      Ta    Yes      Ta    closed by Sx \&Brc  
 .It Sx \&Dc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Do  
 .It Sx \&Do  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Dc  
 .It Sx \&Ec  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Eo  
 .It Sx \&Eo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Ec  
 .It Sx \&Fc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Fo  
 .It Sx \&Fo  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Fc  
 .It Sx \&Oc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Oo  
 .It Sx \&Oo  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Oc  
 .It Sx \&Pc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Po  
 .It Sx \&Po  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Pc  
 .It Sx \&Qc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Oo  
 .It Sx \&Qo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Oc  
 .It Sx \&Re  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Rs  
 .It Sx \&Rs  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Re  
 .It Sx \&Sc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&So  
 .It Sx \&So  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Sc  
 .It Sx \&Xc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Xo  
 .It Sx \&Xo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Xc  
 .El  .El
 .  .Ss Spacing control
 .  .Bl -column "Brq, Bro, Brc" description
 .Ss Block partial-implicit  .It Ic \&Pf Ta prefix, no following horizontal space (one argument)
 Like block full-implicit, but with single-line scope closed by  .It Ic \&Ns Ta roman font, no preceding horizontal space (no arguments)
 .Sx Reserved Characters  .It Ic \&Ap Ta apostrophe without surrounding whitespace (no arguments)
 or end of line.  .It Ic \&Sm Ta switch horizontal spacing mode: Op Cm on | off
 .Bd -literal -offset indent  .It Ic \&Bk , \&Ek Ta keep block: Fl words
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBbody...\(rB \(lBres...\(rB  
 .Ed  
 .  
 .Pp  
 .Bl -column "MacroX" "CallableX" "ParsableX" -compact -offset indent  
 .It Em Macro Ta Em Callable Ta Em Parsable  
 .It Sx \&Aq  Ta    Yes      Ta    Yes  
 .It Sx \&Bq  Ta    Yes      Ta    Yes  
 .It Sx \&Brq Ta    Yes      Ta    Yes  
 .It Sx \&D1  Ta    \&No     Ta    \&Yes  
 .It Sx \&Dl  Ta    \&No     Ta    Yes  
 .It Sx \&Dq  Ta    Yes      Ta    Yes  
 .It Sx \&Op  Ta    Yes      Ta    Yes  
 .It Sx \&Pq  Ta    Yes      Ta    Yes  
 .It Sx \&Ql  Ta    Yes      Ta    Yes  
 .It Sx \&Qq  Ta    Yes      Ta    Yes  
 .It Sx \&Sq  Ta    Yes      Ta    Yes  
 .It Sx \&Vt  Ta    Yes      Ta    Yes  
 .El  .El
 .Pp  .Ss Semantic markup for command line utilities
 Note that the  .Bl -column "Brq, Bro, Brc" description
 .Sx \&Vt  .It Ic \&Nm Ta start a SYNOPSIS block with the name of a utility
 macro is a  .It Ic \&Fl Ta command line options (flags) (>=0 arguments)
 .Sx Block partial-implicit  .It Ic \&Cm Ta command modifier (>0 arguments)
 only when invoked as the first macro  .It Ic \&Ar Ta command arguments (>=0 arguments)
 in a SYNOPSIS section line, else it is  .It Ic \&Op , \&Oo , \&Oc Ta optional syntax elements (enclosure)
 .Sx In-line .  .It Ic \&Ic Ta internal or interactive command (>0 arguments)
 .  .It Ic \&Ev Ta environmental variable (>0 arguments)
 .  .It Ic \&Pa Ta file system path (>=0 arguments)
 .Ss In-line  
 Closed by  
 .Sx Reserved Characters ,  
 end of line, fixed argument lengths, and/or subsequent macros.  In-line  
 macros have only text children.  If a number (or inequality) of  
 arguments is  
 .Pq n ,  
 then the macro accepts an arbitrary number of arguments.  
 .Bd -literal -offset indent  
 \&.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 arg0 arg1 argN  
 .Ed  
 .  
 .Pp  
 .Bl -column "MacroX" "CallableX" "ParsableX" "Arguments" -compact -offset indent  
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Arguments  
 .It Sx \&%A  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 \&%D  Ta    \&No     Ta    \&No     Ta    >0  
 .It Sx \&%I  Ta    \&No     Ta    \&No     Ta    >0  
 .It Sx \&%J  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 \&%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 \&%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 \&Ad  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&An  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Ap  Ta    Yes      Ta    Yes      Ta    0  
 .It Sx \&Ar  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&At  Ta    Yes      Ta    Yes      Ta    1  
 .It Sx \&Bsx Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Bt  Ta    \&No     Ta    \&No     Ta    0  
 .It Sx \&Bx  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Cd  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&Cm  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Db  Ta    \&No     Ta    \&No     Ta    1  
 .It Sx \&Dd  Ta    \&No     Ta    \&No     Ta    >0  
 .It Sx \&Dt  Ta    \&No     Ta    \&No     Ta    n  
 .It Sx \&Dv  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 \&En  Ta    \&No     Ta    \&No     Ta    0  
 .It Sx \&Er  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&Es  Ta    \&No     Ta    \&No     Ta    0  
 .It Sx \&Ev  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Ex  Ta    \&No     Ta    \&No     Ta    n  
 .It Sx \&Fa  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Fd  Ta    \&No     Ta    \&No     Ta    >0  
 .It Sx \&Fl  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Fn  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&Fr  Ta    \&No     Ta    \&No     Ta    n  
 .It Sx \&Ft  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 \&Ic  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&In  Ta    \&No     Ta    \&No     Ta    n  
 .It Sx \&Lb  Ta    \&No     Ta    \&No     Ta    1  
 .It Sx \&Li  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Lk  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Lp  Ta    \&No     Ta    \&No     Ta    0  
 .It Sx \&Ms  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&Mt  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&Nm  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&No  Ta    Yes      Ta    Yes      Ta    0  
 .It Sx \&Ns  Ta    Yes      Ta    Yes      Ta    0  
 .It Sx \&Nx  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Os  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 \&Pa  Ta    Yes      Ta    Yes      Ta    n  
 .It Sx \&Pf  Ta    Yes      Ta    Yes      Ta    1  
 .It Sx \&Pp  Ta    \&No     Ta    \&No     Ta    0  
 .It Sx \&Rv  Ta    \&No     Ta    \&No     Ta    n  
 .It Sx \&Sm  Ta    \&No     Ta    \&No     Ta    1  
 .It Sx \&St  Ta    \&No     Ta    Yes      Ta    1  
 .It Sx \&Sx  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&Sy  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&Tn  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&Ud  Ta    \&No     Ta    \&No     Ta    0  
 .It Sx \&Ux  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 \&Xr  Ta    Yes      Ta    Yes      Ta    >0  
 .It Sx \&br  Ta    \&No     Ta    \&No     Ta    0  
 .It Sx \&sp  Ta    \&No     Ta    \&No     Ta    1  
 .El  .El
 .  .Ss Semantic markup for function libraries
 .  .Bl -column "Brq, Bro, Brc" description
 .Sh REFERENCE  .It Ic \&Lb Ta function library (one argument)
   .It Ic \&In Ta include file (one argument)
   .It Ic \&Fd Ta other preprocessor directive (>0 arguments)
   .It Ic \&Ft Ta function type (>0 arguments)
   .It Ic \&Fo , \&Fc Ta function block: Ar funcname
   .It Ic \&Fn Ta function name: Ar funcname Op Ar argument ...
   .It Ic \&Fa Ta function argument (>0 arguments)
   .It Ic \&Vt Ta variable type (>0 arguments)
   .It Ic \&Va Ta variable name (>0 arguments)
   .It Ic \&Dv Ta defined variable or preprocessor constant (>0 arguments)
   .It Ic \&Er Ta error constant (>0 arguments)
   .It Ic \&Ev Ta environmental variable (>0 arguments)
   .El
   .Ss Various semantic markup
   .Bl -column "Brq, Bro, Brc" description
   .It Ic \&An Ta author name (>0 arguments)
   .It Ic \&Lk Ta hyperlink: Ar uri Op Ar display_name
   .It Ic \&Mt Ta Do mailto Dc hyperlink: Ar localpart Ns @ Ns Ar domain
   .It Ic \&Cd Ta kernel configuration declaration (>0 arguments)
   .It Ic \&Ad Ta memory address (>0 arguments)
   .It Ic \&Ms Ta mathematical symbol (>0 arguments)
   .El
   .Ss Physical markup
   .Bl -column "Brq, Bro, Brc" description
   .It Ic \&Em Ta italic font or underline (emphasis) (>0 arguments)
   .It Ic \&Sy Ta boldface font (symbolic) (>0 arguments)
   .It Ic \&No Ta return to roman font (normal) (>0 arguments)
   .It Ic \&Bf , \&Ef Ta font block: Fl Ar type | Cm \&Em | \&Li | \&Sy
   .El
   .Ss Physical enclosures
   .Bl -column "Brq, Bro, Brc" description
   .It Ic \&Dq , \&Do , \&Dc Ta enclose in typographic double quotes: Dq text
   .It Ic \&Qq , \&Qo , \&Qc Ta enclose in typewriter double quotes: Qq text
   .It Ic \&Sq , \&So , \&Sc Ta enclose in single quotes: Sq text
   .It Ic \&Pq , \&Po , \&Pc Ta enclose in parentheses: Pq text
   .It Ic \&Bq , \&Bo , \&Bc Ta enclose in square brackets: Bq text
   .It Ic \&Brq , \&Bro , \&Brc Ta enclose in curly braces: Brq text
   .It Ic \&Aq , \&Ao , \&Ac Ta enclose in angle brackets: Aq text
   .It Ic \&Eo , \&Ec Ta generic enclosure
   .El
   .Ss Text production
   .Bl -column "Brq, Bro, Brc" description
   .It Ic \&Ex Fl std Ta standard command exit values: Op Ar utility ...
   .It Ic \&Rv Fl std Ta standard function return values: Op Ar function ...
   .It Ic \&St Ta reference to a standards document (one argument)
   .It Ic \&At Ta At
   .It Ic \&Bx Ta Bx
   .It Ic \&Bsx Ta Bsx
   .It Ic \&Nx Ta Nx
   .It Ic \&Fx Ta Fx
   .It Ic \&Ox Ta Ox
   .It Ic \&Dx Ta Dx
   .El
   .Sh MACRO 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 .
 .  .Bl -tag -width 3n
 .Ss \&%A  .It Ic \&%A Ar first_name ... last_name
 Author name of an  Author name of an
 .Sx \&Rs  .Ic \&Rs
 block.  Multiple authors should each be accorded their own  block.
 .Sx \%%A  Multiple authors should each be accorded their own
 line.  Author names should be ordered with full or abbreviated  .Ic \%%A
 forename(s) first, then full surname.  line.
 .  Author names should be ordered with full or abbreviated forename(s)
 .Ss \&%B  first, then full surname.
   .It Ic \&%B Ar title
 Book title of an  Book title of an
 .Sx \&Rs  .Ic \&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.
 .  .It Ic \&%C Ar location
 .Ss \&%C  
 Publication city or location of an  Publication city or location of an
 .Sx \&Rs  .Ic \&Rs
 block.  block.
 .Pp  .It Ic \&%D Oo Ar month day , Oc Ar year
 .Em Remarks :  
 this macro is not implemented in  
 .Xr groff 1 .  
 .  
 .Ss \&%D  
 Publication date of an  Publication date of an
 .Sx \&Rs  .Ic \&Rs
 block.  This should follow the reduced or canonical form syntax  block.
 described in  Provide the full English name of the
 .Sx Dates .  .Ar month
 .  and all four digits of the
 .Ss \&%I  .Ar year .
   .It Ic \&%I Ar name
 Publisher or issuer name of an  Publisher or issuer name of an
 .Sx \&Rs  .Ic \&Rs
 block.  block.
 .  .It Ic \&%J Ar name
 .Ss \&%J  
 Journal name of an  Journal name of an
 .Sx \&Rs  .Ic \&Rs
 block.  block.
 .  .It Ic \&%N Ar number
 .Ss \&%N  
 Issue number (usually for journals) of an  Issue number (usually for journals) of an
 .Sx \&Rs  .Ic \&Rs
 block.  block.
 .  .It Ic \&%O Ar line
 .Ss \&%O  
 Optional information of an  Optional information of an
 .Sx \&Rs  .Ic \&Rs
 block.  block.
 .  .It Ic \&%P Ar number
 .Ss \&%P  
 Book or journal page number of an  Book or journal page number of an
 .Sx \&Rs  .Ic \&Rs
 block.  block.
 .  Conventionally, the argument starts with
 .Ss \&%Q  .Ql p.\&
   for a single page or
   .Ql pp.\&
   for a range of pages, for example:
   .Pp
   .Dl .%P pp. 42\e(en47
   .It Ic \&%Q Ar name
 Institutional author (school, government, etc.) of an  Institutional author (school, government, etc.) of an
 .Sx \&Rs  .Ic \&Rs
 block.  Multiple institutional authors should each be accorded their own  block.
 .Sx \&%Q  Multiple institutional authors should each be accorded their own
   .Ic \&%Q
 line.  line.
 .  .It Ic \&%R Ar name
 .Ss \&%R  
 Technical report name of an  Technical report name of an
 .Sx \&Rs  .Ic \&Rs
 block.  block.
 .  .It Ic \&%T Ar title
 .Ss \&%T  
 Article title of an  Article title of an
 .Sx \&Rs  .Ic \&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  .It Ic \&%U Ar protocol Ns :// Ns Ar path
 URI of reference document.  URI of reference document.
 .  .It Ic \&%V Ar number
 .Ss \&%V  
 Volume number of an  Volume number of an
 .Sx \&Rs  .Ic \&Rs
 block.  block.
 .  .It Ic \&Ac
 .Ss \&Ac  Close an
 Closes an  .Ic \&Ao
 .Sx \&Ao  block.
 block.  Does not have any tail arguments.  Does not have any tail arguments.
 .  .It Ic \&Ad Ar address
 .Ss \&Ad  Memory address.
 Address construct: usually in the context of an computational address in  Do not use this for postal addresses.
 memory, not a physical (post) address.  
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Ad [0,$]
 \&.Ad [0,$]  .Dl \&.Ad 0x00000000
 \&.Ad 0x00000000  .It Ic \&An Fl split | nosplit | Ar first_name ... last_name
 .Ed  Author name.
 .  Can be used both for the authors of the program, function, or driver
 .Ss \&An  documented in the manual, or for the authors of the manual itself.
 Author name.  This macro may alternatively accepts the following  Requires either the name of an author or one of the following arguments:
 arguments, although these may not be specified along with a parameter:  .Pp
 .Bl -tag -width 12n -offset indent  .Bl -tag -width "-nosplitX" -offset indent -compact
 .It Fl split  .It Fl split
 Renders a line break before each author listing.  Start a new output line before each subsequent invocation of
   .Ic \&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 \&Mt kristaps@bsd.lv
 \&.An J. E. Hopcraft ,  .It Ic \&Ao Ar block
 \&.An J. D. Ullman .  Begin a block enclosed by angle brackets.
 .Ed  Does not have any head arguments.
   This macro is almost never useful.
   See
   .Ic \&Aq
   for more details.
   .It Ic \&Ap
   Inserts an apostrophe without any surrounding whitespace.
   This is generally used as a grammatical device when referring to the verb
   form of a function.
 .Pp  .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  
 Begins a block enclosed by angled brackets.  Does not have any head  
 arguments.  
 .Pp  
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Fn execve \&Ap d
 \&.Fl -key= Ns Ao Ar val Ac  .It Ic \&Aq Ar line
 .Ed  Enclose the rest of the input line in angle brackets.
   The only important use case is for email addresses.
   See
   .Ic \&Mt
   for an example.
 .Pp  .Pp
 See also  Occasionally, it is used for names of characters and keys, for example:
 .Sx \&Aq .  
 .  
 .Ss \&Ap  
 Inserts an apostrophe without any surrounding white-space.  This is  
 generally used as a grammatic device when referring to the verb form of  
 a function:  
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Fn execve Ap d  Press the
   \&.Aq escape
   key to ...
 .Ed  .Ed
 .  
 .Ss \&Aq  
 Encloses its arguments in angled brackets.  
 .Pp  .Pp
 Examples:  For URIs, use
 .Bd -literal -offset indent  .Ic \&Lk
 \&.Fl -key= Ns Aq Ar val  instead, and
 .Ed  .Ic \&In
   for
   .Dq #include
   directives.
   Never wrap
   .Ic \&Ar
   in
   .Ic \&Aq .
 .Pp  .Pp
 .Em Remarks :  Since
 this macro is often abused for rendering URIs, which should instead use  .Ic \&Aq
 .Sx \&Lk  usually renders with non-ASCII characters in non-ASCII output modes,
   do not use it where the ASCII characters
   .Sq <
   and
   .Sq >
   are required as syntax elements.
   Instead, use these characters directly in such cases, combining them
   with the macros
   .Ic \&Pf ,
   .Ic \&Ns ,
 or  or
 .Sx \&Mt ,  .Ic \&Eo
 or to note pre-processor  as needed.
 .Dq Li #include  
 statements, which should use  
 .Sx \&In .  
 .Pp  .Pp
 See also  See also
 .Sx \&Ao .  .Ic \&Ao .
 .  .It Ic \&Ar Op Ar placeholder ...
 .Ss \&Ar  Command arguments.
 Command arguments.  If an argument is not provided, the string  If an argument is not provided, the string
 .Dq file ...  .Dq file ...\&
 is used as a default.  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
 .  .Ic \&Ar
 .Ss \&At  macro are names and placeholders for command arguments;
 Formats an AT&T version.  Accepts at most one parameter:  for fixed strings to be passed verbatim as arguments, use
 .Bl -tag -width 12n -offset indent  .Ic \&Fl
   or
   .Ic \&Cm .
   .It Ic \&At Op Ar version
   Formats an
   .At
   version.
   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 V[.[1-4]]?  .It Cm III
 A system version of  .At III .
 .At .  .It Cm V | V.[1-4]
   A version of
   .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 \&Bsx ,  .Ic \&Bsx ,
 .Sx \&Bx ,  .Ic \&Bx ,
 .Sx \&Dx ,  .Ic \&Dx ,
 .Sx \&Fx ,  .Ic \&Fx ,
 .Sx \&Nx ,  .Ic \&Nx ,
 .Sx \&Ox ,  
 and  and
 .Sx \&Ux .  .Ic \&Ox .
 .  .It Ic \&Bc
 .Ss \&Bc  Close a
 Closes a  .Ic \&Bo
 .Sx \&Bo  block.
 block.  Does not have any tail arguments.  Does not have any tail arguments.
 .  .It Ic \&Bd Fl Ns Ar type Oo Fl offset Ar width Oc Op Fl compact
 .Ss \&Bd  Begin a display block.
 Begins a display block.  A display is collection of macros or text which  Display blocks are used to select a different indentation and
 may be collectively offset or justified in a manner different from that  justification than the one used by the surrounding text.
 of the enclosing context.  By default, the block is preceded by a  They may contain both macro lines and text lines.
 vertical space.  By default, a display block is preceded by a vertical space.
 .Pp  .Pp
 Each display is associated with a type, which must be one of the  The
 following arguments:  .Ar type
 .Bl -tag -width 12n -offset indent  must be one of the following:
 .It Fl ragged  .Bl -tag -width 13n -offset indent
 Only left-justify the block.  .It Fl centered
 .It Fl unfilled  Produce one output line from each input line, and center-justify each line.
 Do not justify the block at all.  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 center 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.
   The most popular is the imaginary macro
 .Ar \&Ds ,  .Ar \&Ds ,
 which resolves to  which resolves to
 .Ar 6n .  .Sy 6n .
 .It  .It
 As a scaling unit following the syntax described in  A scaling width as described in
 .Sx Scaling Widths .  .Xr roff 7 .
 .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  .Pp
 See also  See also
 .Sx \&D1  .Ic \&D1
 and  and
 .Sx \&Dl .  .Ic \&Dl .
 .  .It Ic \&Bf Fl emphasis | literal | symbolic | Cm \&Em | \&Li | \&Sy
 .Ss \&Bf  Change the font mode for a scoped block of text.
 .Ss \&Bk  The
 .Ss \&Bl  .Fl emphasis
 .\" Begins a list composed of one or more list entries.  A list entry is  and
 .\" specified by the  .Cm \&Em
 .\" .Sx \&It  argument are equivalent, as are
 .\" macro, which consists of a head and optional body.  By default, a list  .Fl symbolic
 .\" is preceded by a blank line.  A list must specify one of the following  and
 .\" list types:  .Cm \&Sy ,
 .\" .Bl -tag -width 12n  and
 .\" .It Fl bullet  .Fl literal
 .\" A list offset by a bullet.  The head of list entries must be empty.  and
 .\" List entry bodies are justified after the bullet.  .Cm \&Li .
 .\" .It Fl column  Without an argument, this macro does nothing.
 .\" A columnated list.  The number of columns is specified as arguments to  The font mode continues until broken by a new font mode in a nested
 .\" the  scope or
 .\" .Sx \&Bl  .Ic \&Ef
 .\" macro (the deprecated form of following the invocation of  is encountered.
 .\" .Fl column  
 .\" is also accepted).  Arguments dictate the width of columns specified in  
 .\" list entries.  List entry bodies must be left empty.  Columns specified  
 .\" in the list entry head are justified to their position in the sequence  
 .\" of columns.  
 .\" .It Fl dash  
 .\" A list offset by a dash (hyphen).  The head of list entries must be  
 .\" empty.  List entry bodies are justified past the dash.  
 .\" .It Fl diag  
 .\" Like  
 .\" .Fl inset  
 .\" lists, but with additional formatting to the head.  
 .\" .It Fl enum  
 .\" A list offset by a number indicating list entry position.  The head of  
 .\" list entries must be empty.  List entry bodies are justified past the  
 .\" enumeration.  
 .\" .It Fl hang  
 .\" Like  
 .\" .Fl tag ,  
 .\" but instead of list bodies justifying to the head on the first line,  
 .\" they trail the head text.  
 .\" .It Fl hyphen  
 .\" Synonym for  
 .\" .Fl dash .  
 .\" .It Fl inset  
 .\" Like  
 .\" .Fl tag ,  
 .\" but list entry bodies aren't justified.  
 .\" .It Fl item  
 .\" An un-justified list.  This produces blocks of text.  
 .\" .It Fl ohang  
 .\" List bodies are placed on the line following the head.  
 .\" .It Fl tag  
 .\" A list offset by list entry heads.  List entry bodies are justified  
 .\" after the head.  
 .\" .El  
 .\" .Pp  
 .\" More...  
 .\" .  
 .Ss \&Bo  
 Begins a block enclosed by square brackets.  Does not have any head  
 arguments.  
 .Pp  .Pp
 Examples:  See also
   .Ic \&Li ,
   .Ic \&Ef ,
   .Ic \&Em ,
   and
   .Ic \&Sy .
   .It Ic \&Bk Fl words
   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.
   .Pp
   The
   .Fl words
   argument is required; additional arguments are ignored.
   .Pp
   The following example will not break within each
   .Ic \&Op
   macro line:
 .Bd -literal -offset indent  .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.
   .It Xo
   .Ic \&Bl
   .Fl Ns Ar type
   .Op Fl width Ar val
   .Op Fl offset Ar val
   .Op Fl compact
   .Op Ar col ...
   .Xc
   Begin a list.
   Lists consist of items specified using the
   .Ic \&It
   macro, containing a head or a body or both.
   .Pp
   The list
   .Ar type
   is mandatory and must be specified first.
   The
   .Fl width
   and
   .Fl offset
   arguments accept macro names as described for
   .Ic \&Bd
   .Fl offset ,
   scaling widths as described in
   .Xr roff 7 ,
   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, the string length of each argument
   specifies the width of one column.
   If the first line of the body of a
   .Fl column
   list is not an
   .Ic \&It
   macro line,
   .Ic \&It
   contexts spanning one input line each are implied until an
   .Ic \&It
   macro line is encountered, at which point items start being interpreted as
   described in the
   .Ic \&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
   .Ic \&El
   and
   .Ic \&It .
   .It Ic \&Bo Ar block
   Begin a block enclosed by square brackets.
   Does not have any head arguments.
   .Pp
   Examples:
   .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 .  .Ic \&Bq .
 .  .It Ic \&Bq Ar line
 .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
 commands; the correct macros to use for this purpose are  commands; the correct macros to use for this purpose are
 .Sx \&Op ,  .Ic \&Op ,
 .Sx \&Oo ,  .Ic \&Oo ,
 and  and
 .Sx \&Oc .  .Ic \&Oc .
 .Pp  .Pp
 See also  See also
 .Sx \&Bo .  .Ic \&Bo .
 .  .It Ic \&Brc
 .Ss \&Brc  Close a
 Closes a  .Ic \&Bro
 .Sx \&Bro  block.
 block.  Does not have any tail arguments.  Does not have any tail arguments.
 .  .It Ic \&Bro Ar block
 .Ss \&Bro  Begin a block enclosed by curly braces.
 Begins a block enclosed by curly braces.  Does not have any head  Does not have any head arguments.
 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 .  .Ic \&Brq .
 .  .It Ic \&Brq Ar line
 .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 .  .Ic \&Bro .
 .  .It Ic \&Bsx Op Ar version
 .Ss \&Bsx  Format the
 Format the BSD/OS version provided as an argument, or a default value if  .Bsx
   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 ,  .Ic \&At ,
 .Sx \&Bx ,  .Ic \&Bx ,
 .Sx \&Dx ,  .Ic \&Dx ,
 .Sx \&Fx ,  .Ic \&Fx ,
 .Sx \&Nx ,  .Ic \&Nx ,
 .Sx \&Ox ,  
 and  and
 .Sx \&Ux .  .Ic \&Ox .
 .  .It Ic \&Bt
 .Ss \&Bt  Supported only for compatibility, do not use this in new manuals.
 Prints  Prints
 .Dq is currently in beta test.  .Dq is currently in beta test.
 .  .It Ic \&Bx Op Ar version Op Ar variant
 .Ss \&Bx  Format the
 Format the BSD version provided as an argument, or a default value if no  .Bx
   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 ,  .Ic \&At ,
 .Sx \&Bsx ,  .Ic \&Bsx ,
 .Sx \&Dx ,  .Ic \&Dx ,
 .Sx \&Fx ,  .Ic \&Fx ,
 .Sx \&Nx ,  .Ic \&Nx ,
 .Sx \&Ox ,  
 and  and
 .Sx \&Ux .  .Ic \&Ox .
 .  .It Ic \&Cd Ar line
 .Ss \&Cd  Kernel configuration declaration.
 Configuration declaration (suggested for use only in section four  This denotes strings accepted by
 manuals).  This denotes strings accepted by  
 .Xr config 8 .  .Xr config 8 .
   It is most often used in section 4 manual pages.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Cd device le0 at scode?
 \&.Cd device le0 at scode?  
 .Ed  
 .Pp  .Pp
 .Em Remarks :  .Em Remarks :
 this macro is commonly abused by using quoted literals to retain  this macro is commonly abused by using quoted literals to retain
 white-space and align consecutive  whitespace and align consecutive
 .Sx \&Cd  .Ic \&Cd
 declarations.  This practise is discouraged.  declarations.
 .  This practise is discouraged.
 .Ss \&Cm  .It Ic \&Cm Ar keyword ...
 Command modifiers.  Useful when specifying configuration options or  Command modifiers.
 keys.  Typically used for fixed strings passed as arguments to interactive
   commands, to commands in interpreted scripts, or to configuration
   file directives, unless
   .Ic \&Fl
   is more appropriate.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl ".Nm mt Fl f Ar device Cm rewind"
 \&.Cm ControlPath  .Dl ".Nm ps Fl o Cm pid , Ns Cm command"
 \&.Cm ControlMaster  .Dl ".Nm dd Cm if= Ns Ar file1 Cm of= Ns Ar file2"
 .Ed  .Dl ".Ic set Fl o Cm vi"
   .Dl ".Ic lookup Cm file bind"
   .Dl ".Ic permit Ar identity Op Cm as Ar target"
   .It Ic \&D1 Ar line
   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  .Pp
 See also  
 .Sx \&Fl .  
 .  
 .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:  Examples:
 .Bd -literal -offset indent  .Dl \&.D1 \&Fl abcdefgh
 \&.D1 Fl abcdefgh  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Bd  .Ic \&Bd
 and  and
 .Sx \&Dl .  .Ic \&Dl .
 .  .It Ic \&Db
 .Ss \&Db  This macro is obsolete.
 .Ss \&Dc  No replacement is needed.
 Closes a  It is ignored by
 .Sx \&Do  .Xr mandoc 1
 block.  Does not have any tail arguments.  and groff including its arguments.
 .  It was formerly used to toggle a debugging mode.
 .Ss \&Dd  .It Ic \&Dc
 Document date.  This is the mandatory first macro of any  Close a
   .Ic \&Do
   block.
   Does not have any tail arguments.
   .It Ic \&Dd Cm $\&Mdocdate$ | Ar month day , year
   Document date for display in the page footer.
   This is the mandatory first macro of any
 .Nm  .Nm
 manual.  Its calling syntax is as follows:  manual.
 .Pp  .Pp
 .D1 \. Ns Sx \&Dd Cm date  
 .Pp  
 The  The
 .Cm date  .Ar month
 field may be either  is the full English month name, the
 .Ar $\&Mdocdate$ ,  .Ar day
 which signifies the current manual revision date dictated by  is an integer number, 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 ,  .Xr cvs 1 ,
 or instead a valid canonical date as specified by  the special string
 .Sx Dates .  .Dq $\&Mdocdate$
 If a date does not conform, the current date is used instead.  can be given as an argument.
   .It
   The traditional, purely numeric
   .Xr man 7
   format
   .Ar year Ns \(en Ns Ar month Ns \(en Ns Ar day
   is accepted, too.
   .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  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Dd $\&Mdocdate$
 \&.Dd $\&Mdocdate$  .Dl \&.Dd $\&Mdocdate: July 2 2018$
 \&.Dd $\&Mdocdate: July 21 2007$  .Dl \&.Dd July 2, 2018
 \&.Dd July 21, 2007  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Dt  .Ic \&Dt
 and  and
 .Sx \&Os .  .Ic \&Os .
 .  .It Ic \&Dl Ar line
 .Ss \&Dl  One-line indented display.
 One-line intended display.  This is formatted as literal text and is  This is formatted as literal text and is useful for commands and
 useful for commands and invocations.  It is followed by a newline.  invocations.
   It is followed by a newline.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Dl % mandoc mdoc.7 \e(ba less
 \&.Dl % mandoc mdoc.7 | less  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Bd  .Ic \&Ql ,
   .Ic \&Bd Fl literal ,
 and  and
 .Sx \&D1 .  .Ic \&D1 .
 .  .It Ic \&Do Ar block
 .Ss \&Do  Begin a block enclosed by double quotes.
 Begins a block enclosed by double quotes.  Does not have any head  Does not have any head arguments.
 arguments.  
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Bd -literal -offset indent -compact
 \&.D1 Do April is the cruellest month Dc \e(em T.S. Eliot  \&.Do
   April is the cruellest month
   \&.Dc
   \e(em T.S. Eliot
 .Ed  .Ed
 .Pp  .Pp
 See also  See also
 .Sx \&Dq .  .Ic \&Dq .
 .  .It Ic \&Dq Ar line
 .Ss \&Dq  Encloses its arguments in
 Encloses its arguments in double quotes.  .Dq typographic
   double-quotes.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Bd -literal -offset indent -compact
 \&.Dq April is the cruellest month  \&.Dq April is the cruellest month
 \e(em T.S. Eliot  \e(em T.S. Eliot
 .Ed  .Ed
 .Pp  .Pp
 See also  See also
 .Sx \&Do .  .Ic \&Qq ,
 .  .Ic \&Sq ,
 .Ss \&Dt  and
 Document title.  This is the mandatory second macro of any  .Ic \&Do .
   .It Ic \&Dt Ar TITLE section Op Ar arch
   Document title for display in the page header.
   This is the mandatory second macro of any
 .Nm  .Nm
 file.  Its calling syntax is as follows:  file.
 .Pp  .Pp
 .D1 \. Ns Sx \&Dt Cm title section Op Cm volume | arch  
 .Pp  
 Its arguments are as follows:  Its arguments are as follows:
 .Bl -tag -width Ds -offset Ds  .Bl -tag -width section -offset 2n
 .It Cm title  .It Ar TITLE
 The document's title (name).  This should be capitalised and is  The document's title (name), defaulting to
 required.  .Dq UNTITLED
 .It Cm section  if unspecified.
 The manual section.  This may be one of  To achieve a uniform appearance of page header lines,
 .Ar 1  it should by convention be all caps.
 .Pq utilities ,  .It Ar section
 .Ar 2  The manual section.
 .Pq system calls ,  This may be one of
 .Ar 3  .Cm 1
 .Pq libraries ,  .Pq General Commands ,
 .Ar 3p  .Cm 2
 .Pq Perl libraries ,  .Pq System Calls ,
 .Ar 4  .Cm 3
 .Pq devices ,  .Pq Library Functions ,
 .Ar 5  .Cm 3p
 .Pq file formats ,  .Pq Perl Library ,
 .Ar 6  .Cm 4
 .Pq games ,  .Pq Device Drivers ,
 .Ar 7  .Cm 5
 .Pq miscellaneous ,  .Pq File Formats ,
 .Ar 8  .Cm 6
 .Pq system utilities ,  .Pq Games ,
 .Ar 9  .Cm 7
 .Pq kernel functions ,  .Pq Miscellaneous Information ,
 .Ar X11  .Cm 8
 .Pq X Window System ,  .Pq System Manager's Manual ,
 .Ar X11R6  
 .Pq X Window System ,  
 .Ar unass  
 .Pq unassociated ,  
 .Ar local  
 .Pq local system ,  
 .Ar draft  
 .Pq draft manual ,  
 or  or
 .Ar paper  .Cm 9
 .Pq paper .  .Pq Kernel Developer's Manual .
 It is also required and should correspond to the manual's filename  It should correspond to the manual's filename suffix and defaults to
 suffix.  the empty string if unspecified.
 .It Cm volume  .It Ar arch
 This overrides the volume inferred from  This specifies the machine architecture a manual page applies to,
 .Ar section .  where relevant, for example
 This field is optional, and if specified, must be one of  .Cm alpha ,
 .Ar USD  .Cm amd64 ,
 .Pq users' supplementary documents ,  .Cm i386 ,
 .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  or
 .Ar CON  .Cm sparc64 .
 .Pq contributed manuals .  The list of valid architectures varies by operating system.
 .It Cm arch  
 This specifies a specific relevant architecture.  If  
 .Cm 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 mvme68k ,  
 .Ar mvme88k ,  
 .Ar mvmeppc ,  
 .Ar pmax ,  
 .Ar sgi ,  
 .Ar socppc ,  
 .Ar sparc ,  
 .Ar sparc64 ,  
 .Ar sun3 ,  
 .Ar vax ,  
 or  
 .Ar zaurus .  
 .El  .El
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Dt FOO 1
 \&.Dt FOO 1  .Dl \&.Dt FOO 9 i386
 \&.Dt FOO 4 KM  
 \&.Dt FOO 9 i386  
 \&.Dt FOO 9 KM i386  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Dd  .Ic \&Dd
 and  and
 .Sx \&Os .  .Ic \&Os .
 .  .It Ic \&Dv Ar identifier ...
 .Ss \&Dv  Defined variables such as preprocessor constants, constant symbols,
 Defined variables such as preprocessor constants.  enumeration values, and so on.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Dv NULL
 \&.Dv BUFSIZ  .Dl \&.Dv BUFSIZ
 \&.Dv STDOUT_FILENO  .Dl \&.Dv STDOUT_FILENO
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Er .  .Ic \&Er
 .  and
 .Ss \&Dx  .Ic \&Ev
 Format the DragonFly BSD version provided as an argument, or a default  for special-purpose constants,
   .Ic \&Va
   for variable symbols, and
   .Ic \&Fd
   for listing preprocessor variable definitions in the
   .Em SYNOPSIS .
   .It Ic \&Dx Op Ar version
   Format the
   .Dx
   version provided as an argument, or a default
 value if no argument is provided.  value if no argument is provided.
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Dx 2.4.1
 \&.Dx 2.4.1  .Dl \&.Dx
 \&.Dx  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Ic \&At ,
 .Sx \&Bsx ,  .Ic \&Bsx ,
 .Sx \&Bx ,  .Ic \&Bx ,
 .Sx \&Fx ,  .Ic \&Fx ,
 .Sx \&Nx ,  .Ic \&Nx ,
 .Sx \&Ox ,  
 and  and
 .Sx \&Ux .  .Ic \&Ox .
 .  .It Ic \&Ec Op Ar closing_delimiter
 .Ss \&Ec  Close a scope started by
 .Ss \&Ed  .Ic \&Eo .
 .Ss \&Ef  
 .Ss \&Ek  
 .Ss \&El  
 .Ss \&Em  
 Denotes text that should be emphasised.  Note that this is a  
 presentation term and should not be used for stylistically decorating  
 technical terms.  
 .Pp  .Pp
   The
   .Ar closing_delimiter
   argument is used as the enclosure tail, for example, specifying \e(rq
   will emulate
   .Ic \&Dc .
   .It Ic \&Ed
   End a display context started by
   .Ic \&Bd .
   .It Ic \&Ef
   End a font mode context started by
   .Ic \&Bf .
   .It Ic \&Ek
   End a keep context started by
   .Ic \&Bk .
   .It Ic \&El
   End a list context started by
   .Ic \&Bl .
   See also
   .Ic \&It .
   .It Ic \&Em Ar word ...
   Request an italic font.
   If the output device does not provide that, underline.
   .Pp
   This is most often used for stress emphasis (not to be confused with
   importance, see
   .Ic \&Sy ) .
   In the rare cases where none of the semantic markup macros fit,
   it can also be used for technical terms and placeholders, except
   that for syntax elements,
   .Ic \&Sy
   and
   .Ic \&Ar
   are preferred, respectively.
   .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Bd -literal -compact -offset indent
 \&.Ed Warnings!  Selected lines are those
 \&.Ed Remarks :  \&.Em not
   matching any of the specified patterns.
   Some of the functions use a
   \&.Em hold space
   to save the pattern space for subsequent retrieval.
 .Ed  .Ed
 .  
 .Ss \&En  
 .Ss \&Eo  
 .Ss \&Er  
 Error constants (suggested for use only in section two manuals).  
 .Pp  .Pp
   See also
   .Ic \&No ,
   .Ic \&Ql ,
   and
   .Ic \&Sy .
   .It Ic \&En Ar word ...
   This macro is obsolete.
   Use
   .Ic \&Eo
   or any of the other enclosure macros.
   .Pp
   It encloses its argument in the delimiters specified by the last
   .Ic \&Es
   macro.
   .It Ic \&Eo Op Ar opening_delimiter
   An arbitrary enclosure.
   The
   .Ar opening_delimiter
   argument is used as the enclosure head, for example, specifying \e(lq
   will emulate
   .Ic \&Do .
   .It Ic \&Er Ar identifier ...
   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:  Examples:
 .Bd -literal -offset indent  .Dl \&.Er EPERM
 \&.Er EPERM  .Dl \&.Er ENOENT
 \&.Er ENOENT  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Dv .  .Ic \&Dv
 .  for general constants.
 .Ss \&Es  .It Ic \&Es Ar opening_delimiter closing_delimiter
 .  This macro is obsolete.
 .Ss \&Ev  Use
   .Ic \&Eo
   or any of the other enclosure macros.
   .Pp
   It takes two arguments, defining the delimiters to be used by subsequent
   .Ic \&En
   macros.
   .It Ic \&Ev Ar identifier ...
 Environmental variables such as those specified in  Environmental variables such as those specified in
 .Xr environ 7 .  .Xr environ 7 .
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Ev DISPLAY
 \&.Ev DISPLAY  .Dl \&.Ev PATH
 \&.Ev PATH  .Pp
 .Ed  See also
 .  .Ic \&Dv
 .Ss \&Ex  for general constants.
 Inserts text regarding a utility's exit values.  This macro must have  .It Ic \&Ex Fl std Op Ar utility ...
 first the  Insert a standard sentence regarding command exit values of 0 on success
 .Fl std  and >0 on failure.
 argument specified, then an optional  This is most often used in section 1, 6, and 8 manual pages.
 .Ar utility .  .Pp
 If  If
 .Ar utility  .Ar utility
 is not provided, the document's name as stipulated in  is not specified, the document's name set by
 .Sx \&Nm  .Ic \&Nm
 is provided.  is used.
 .Ss \&Fa  Multiple
 .Ss \&Fc  .Ar utility
 .Ss \&Fd  arguments are treated as separate utilities.
 .Ss \&Fl  .Pp
 Command-line flag.  Used when listing arguments to command-line  See also
 utilities.  Prints a fixed-width hyphen  .Ic \&Rv .
   .It Ic \&Fa Ar argument ...
   Function argument or parameter.
   Each argument may be a name and a type (recommended for the
   .Em SYNOPSIS
   section), a name alone (for function invocations),
   or a type alone (for function prototypes).
   If both a type and a name are given or if the type consists of multiple
   words, all words belonging to the same function argument have to be
   given in a single argument to the
   .Ic \&Fa
   macro.
   .Pp
   This macro is also used to specify the field name of a structure.
   .Pp
   Most often, the
   .Ic \&Fa
   macro is used in the
   .Em SYNOPSIS
   within
   .Ic \&Fo
   blocks 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
   .Ic \&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 \(dqchar *\(dq size_t
   .Pp
   See also
   .Ic \&Fo .
   .It Ic \&Fc
   End a function context started by
   .Ic \&Fo .
   .It Ic \&Fd Pf # Ar directive Op Ar argument ...
   Preprocessor directive, in particular for listing it in the
   .Em SYNOPSIS .
   Historically, it was also used to document include files.
   The latter usage has been deprecated in favour of
   .Ic \&In .
   .Pp
   Examples:
   .Dl \&.Fd #define sa_handler __sigaction_u.__sa_handler
   .Dl \&.Fd #define SIO_MAXNFDS
   .Dl \&.Fd #ifdef FS_DEBUG
   .Dl \&.Ft void
   .Dl \&.Fn dbg_open \(dqconst char *\(dq
   .Dl \&.Fd #endif
   .Pp
   See also
   .Sx MANUAL STRUCTURE ,
   .Ic \&In ,
   and
   .Ic \&Dv .
   .It Ic \&Fl Op Ar word ...
   Command-line flag or option.
   Used when listing arguments to command-line utilities.
   Prints a fixed-width hyphen
 .Sq \-  .Sq \-
 before each delimited argument.  If no arguments are provided, a hyphen  directly followed by each argument.
 is still printed.  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  .Pp
 Examples:  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
   .Ic \&Cm .
   .It Ic \&Fn Ar funcname Op Ar argument ...
   A function name.
   .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 \(dqint funcname\(dq \(dqint arg0\(dq \(dqint arg1\(dq
   .Dl \&.Fn funcname \(dqint arg0\(dq
   .Dl \&.Fn funcname arg0
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Fl a b c  \&.Ft functype
 \&.Fl  \&.Fn funcname
 \&.Op Fl o Ns Ar file  
 .Ed  .Ed
 .Pp  .Pp
   When referring to a function documented in another manual page, use
   .Ic \&Xr
   instead.
 See also  See also
 .Sx \&Cm .  .Sx MANUAL STRUCTURE ,
 .  .Ic \&Fo ,
 .Ss \&Fn  and
 .Ss \&Fo  .Ic \&Ft .
 .Ss \&Fr  .It Ic \&Fo Ar funcname
 .Ss \&Ft  Begin a function block.
 .Ss \&Fx  This is a multi-line version of
 Format the FreeBSD version provided as an argument, or a default value  .Ic \&Fn .
 if no argument is provided.  
 .Pp  .Pp
   Invocations usually occur in the following context:
   .Bd -ragged -offset indent
   .Pf \. Ic \&Ft Ar functype
   .br
   .Pf \. Ic \&Fo Ar funcname
   .br
   .Pf \. Ic \&Fa Qq Ar argtype Ar argname
   .br
   \&.\.\.
   .br
   .Pf \. Ic \&Fc
   .Ed
   .Pp
   A
   .Ic \&Fo
   scope is closed by
   .Ic \&Fc .
   .Pp
   See also
   .Sx MANUAL STRUCTURE ,
   .Ic \&Fa ,
   .Ic \&Fc ,
   and
   .Ic \&Ft .
   .It Ic \&Fr Ar number
   This macro is obsolete.
   No replacement markup is needed.
   .Pp
   It was used to show numerical function return values in an italic font.
   .It Ic \&Ft Ar functype
   A function type.
   .Pp
   In the
   .Em SYNOPSIS
   section, a new output line is started after this macro.
   .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Ft int
 \&.Fx 7.1  .Bd -literal -offset indent -compact
 \&.Fx  \&.Ft functype
   \&.Fn funcname
 .Ed  .Ed
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Sx MANUAL STRUCTURE ,
 .Sx \&Bsx ,  .Ic \&Fn ,
 .Sx \&Bx ,  
 .Sx \&Dx ,  
 .Sx \&Nx ,  
 .Sx \&Ox ,  
 and  and
 .Sx \&Ux .  .Ic \&Fo .
 .  .It Ic \&Fx Op Ar version
 .Ss \&Hf  Format the
 .Ss \&Ic  .Fx
 .Ss \&In  version provided as an argument, or a default value
 .Ss \&It  if no argument is provided.
 .Ss \&Lb  
 .Ss \&Li  
 .Ss \&Lk  
 Format a hyperlink.  The calling syntax is as follows:  
 .Pp  .Pp
 .D1 \. Ns Sx \&Lk Cm uri Op Cm name  Examples:
   .Dl \&.Fx 7.1
   .Dl \&.Fx
 .Pp  .Pp
   See also
   .Ic \&At ,
   .Ic \&Bsx ,
   .Ic \&Bx ,
   .Ic \&Dx ,
   .Ic \&Nx ,
   and
   .Ic \&Ox .
   .It Ic \&Hf Ar filename
   This macro is not implemented in
   .Xr mandoc 1 .
   It was used to include the contents of a (header) file literally.
   .It Ic \&Ic Ar keyword ...
   Internal or interactive command, or configuration instruction
   in a configuration file.
   See also
   .Ic \&Cm .
   .Pp
 Examples:  Examples:
   .Dl \&.Ic :wq
   .Dl \&.Ic hash
   .Dl \&.Ic alias
   .Pp
   Note that using
   .Ic \&Ql ,
   .Ic \&Dl ,
   or
   .Ic \&Bd Fl literal
   is preferred for displaying code samples; the
   .Ic \&Ic
   macro is used when referring to an individual command name.
   .It Ic \&In Ar filename
   The name of an include file.
   This macro is most often used in section 2, 3, and 9 manual pages.
   .Pp
   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
   .Qq #include ,
   and a blank line is inserted in front if there is a preceding
   function declaration.
   In other sections, it only encloses its argument in angle brackets
   and causes no line break.
   .Pp
   Examples:
   .Dl \&.In sys/types.h
   .Pp
   See also
   .Sx MANUAL STRUCTURE .
   .It Ic \&It Op Ar head
   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 \. Ic \&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 \. Ic \&It
   .Pp
   with subsequent lines interpreted within the scope of the
   .Ic \&It
   until either a closing
   .Ic \&El
   or another
   .Ic \&It .
   .Pp
   The
   .Fl tag
   list has the following syntax:
   .Pp
   .D1 Pf \. Ic \&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 \. Ic \&It Ar cell Op Ic \&Ta Ar cell ...
   .D1 Pf \. Ic \&It Ar cell Op <TAB> 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 the special
   .Ic \&Ta
   block macro or by literal tab characters.
   .Pp
   Using literal tabs is strongly discouraged because they are very
   hard to use correctly and
   .Nm
   code using them is very hard to read.
   In particular, a blank character is syntactically significant
   before and after the literal tab character.
   If a word precedes or follows the tab without an intervening blank,
   that word is never interpreted as a macro call, but always output
   literally.
   .Pp
   The tab cell delimiter may only be used within the
   .Ic \&It
   line itself; on following lines, only the
   .Ic \&Ta
   macro can be used to delimit cells, and portability requires that
   .Ic \&Ta
   is called by other macros: some parsers do not recognize it when
   it appears as the first macro on a line.
   .Pp
   Note that quoted strings may span tab-delimited cells on an
   .Ic \&It
   line.
   For example,
   .Pp
   .Dl .It \(dqcol1 ,\& <TAB> col2 ,\(dq \&;
   .Pp
   will preserve the whitespace before both commas,
   but not the whitespace before the semicolon.
   .Pp
   See also
   .Ic \&Bl .
   .It Ic \&Lb Cm lib Ns Ar name
   Specify a library.
   .Pp
   The
   .Ar name
   parameter may be a system library, such as
   .Cm z
   or
   .Cm pam ,
   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 libmandoc
   .It Ic \&Li Ar word ...
   Request a typewriter (literal) font.
   Deprecated because on terminal output devices, this is usually
   indistinguishable from normal text.
   For literal displays, use
   .Ic \&Ql Pq in-line ,
   .Ic \&Dl Pq single line ,
   or
   .Ic \&Bd Fl literal Pq multi-line
   instead.
   .It Ic \&Lk Ar uri Op Ar display_name
   Format a hyperlink.
   .Pp
   Examples:
   .Dl \&.Lk http://bsd.lv \(dqThe BSD.lv Project\(dq
   .Dl \&.Lk http://bsd.lv
   .Pp
   See also
   .Ic \&Mt .
   .It Ic \&Lp
   Deprecated synonym for
   .Ic \&Pp .
   .It Ic \&Ms Ar name
   Display a mathematical symbol.
   .Pp
   Examples:
   .Dl \&.Ms sigma
   .Dl \&.Ms aleph
   .It Ic \&Mt Ar localpart Ns @ Ns Ar domain
   Format a
   .Dq mailto:
   hyperlink.
   .Pp
   Examples:
   .Dl \&.Mt discuss@manpages.bsd.lv
   .Dl \&.An Kristaps Dzonsons \&Aq \&Mt kristaps@bsd.lv
   .It Ic \&Nd Ar line
   A one line description of the manual's content.
   This is the mandatory last macro of the
   .Em NAME
   section and not appropriate for other sections.
   .Pp
   Examples:
   .Dl Pf . Ic \&Nd mdoc language reference
   .Dl Pf . Ic \&Nd format and display UNIX manuals
   .Pp
   The
   .Ic \&Nd
   macro technically accepts child macros and terminates with a subsequent
   .Ic \&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
   .Ic \&Nm .
   .It Ic \&Nm Op Ar name
   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
   .Ic \&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
   .Ic \&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  .Bd -literal -offset indent
 \&.Lk http://bsd.lv "The BSD.lv Project"  \&.Sh SYNOPSIS
 \&.Lk http://bsd.lv  \&.Nm cat
   \&.Op Fl benstuv
   \&.Op Ar
 .Ed  .Ed
 .Pp  .Pp
 See also  In the
 .Sx \&Mt .  .Em SYNOPSIS
 .  of section 2, 3 and 9 manual pages, use the
 .Ss \&Lp  .Ic \&Fn
 .Ss \&Ms  macro rather than
 .Ss \&Mt  .Ic \&Nm
 .Ss \&Nd  to mark up the name of the manual page.
 .Ss \&Nm  .It Ic \&No Ar word ...
 .Ss \&No  Normal text.
 .Ss \&Ns  Closes the scope of any preceding in-line macro.
 .Ss \&Nx  When used after physical formatting macros like
 Format the NetBSD version provided as an argument, or a default value if  .Ic \&Em
 no argument is provided.  or
   .Ic \&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  .Pp
 Examples:  Examples:
   .Dl ".Em italic , Sy bold , No and roman"
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Nx 5.01  \&.Sm off
 \&.Nx  \&.Cm :C No / Ar pattern No / Ar replacement No /
   \&.Sm on
 .Ed  .Ed
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Ic \&Em ,
 .Sx \&Bsx ,  .Ic \&Ql ,
 .Sx \&Bx ,  
 .Sx \&Dx ,  
 .Sx \&Fx ,  
 .Sx \&Ox ,  
 and  and
 .Sx \&Ux .  .Ic \&Sy .
 .  .It Ic \&Ns
 .Ss \&Oc  Suppress a space between the output of the preceding macro
 .Ss \&Oo  and the following text or macro.
 .Ss \&Op  Following invocation, input is interpreted as normal text
 .Ss \&Os  just like after an
 Document operating system version.  This is the mandatory third macro of  .Ic \&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
   .Ic \&No
   and
   .Ic \&Sm .
   .It Ic \&Nx Op Ar version
   Format the
   .Nx
   version provided as an argument, or a default value if
   no argument is provided.
   .Pp
   Examples:
   .Dl \&.Nx 5.01
   .Dl \&.Nx
   .Pp
   See also
   .Ic \&At ,
   .Ic \&Bsx ,
   .Ic \&Bx ,
   .Ic \&Dx ,
   .Ic \&Fx ,
   and
   .Ic \&Ox .
   .It Ic \&Oc
   Close multi-line
   .Ic \&Oo
   context.
   .It Ic \&Oo Ar block
   Multi-line version of
   .Ic \&Op .
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Oo
   \&.Op Fl flag Ns Ar value
   \&.Oc
   .Ed
   .It Ic \&Op Ar line
   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
   .Ic \&Oo .
   .It Ic \&Os Op Ar system Op Ar version
   Operating system version for display in the page footer.
   This is the mandatory third macro of
 any  any
 .Nm  .Nm
 file.  Its calling syntax is as follows:  file.
 .Pp  .Pp
 .D1 \. Ns Sx \&Os Op Cm system  
 .Pp  
 The optional  The optional
 .Cm system  .Ar system
 parameter specifies the relevant operating system or environment.  Left  parameter specifies the relevant operating system or environment.
 unspecified, it defaults to the local operating system version.  This is  It is suggested to leave it unspecified, in which case
 the suggested form.  .Xr mandoc 1
   uses its
   .Fl Ios
   argument or, if that isn't specified either,
   .Fa sysname
   and
   .Fa release
   as returned by
   .Xr uname 3 .
 .Pp  .Pp
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Os
 \&.Os  .Dl \&.Os KTH/CSC/TCS
 \&.Os KTH/CSC/TCS  .Dl \&.Os BSD 4.3
 \&.Os BSD 4.3  
 .Ed  
 .Pp  .Pp
 See also  See also
 .Sx \&Dd  .Ic \&Dd
 and  and
 .Sx \&Dt .  .Ic \&Dt .
 .  .It Ic \&Ot Ar functype
 .Ss \&Ot  This macro is obsolete.
 Unknown usage.  Use
   .Ic \&Ft
   instead; with
   .Xr mandoc 1 ,
   both have the same effect.
 .Pp  .Pp
 .Em Remarks :  Historical
 this macro has been deprecated.  .Nm
 .  packages described it as
 .Ss \&Ox  .Dq "old function type (FORTRAN)" .
 Format the OpenBSD version provided as an argument, or a default value  .It Ic \&Ox Op Ar version
   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 ,  .Ic \&At ,
 .Sx \&Bsx ,  .Ic \&Bsx ,
 .Sx \&Bx ,  .Ic \&Bx ,
 .Sx \&Dx ,  .Ic \&Dx ,
 .Sx \&Fx ,  .Ic \&Fx ,
 .Sx \&Nx ,  
 and  and
 .Sx \&Ux .  .Ic \&Nx .
 .  .It Ic \&Pa Ar name ...
 .Ss \&Pa  An absolute or relative file system path, or a file or directory name.
 .Ss \&Pc  If an argument is not provided, the character
 .Ss \&Pf  .Sq \(ti
 .Ss \&Po  is used as a default.
 .Ss \&Pp  .Pp
 .Ss \&Pq  Examples:
 .Ss \&Qc  .Dl \&.Pa /usr/bin/mandoc
 .Ss \&Ql  .Dl \&.Pa /usr/share/man/man7/mdoc.7
 .Ss \&Qo  .Pp
 .Ss \&Qq  See also
 .  .Ic \&Lk .
 .Ss \&Re  .It Ic \&Pc
 Closes a  Close parenthesised context opened by
 .Sx \&Rs  .Ic \&Po .
 block.  Does not have any tail arguments.  .It Ic \&Pf Ar prefix macro Op Ar argument ...
 .  Removes the space between its argument and the following macro.
 .Ss \&Rs  It is equivalent to:
 Begins a bibliographic  .Pp
   .D1 Ic \&No Pf \e& Ar prefix Ic \&Ns Ar macro Op Ar argument ...
   .Pp
   The
   .Ar prefix
   argument is not parsed for macro names or delimiters,
   but used verbatim as if it were escaped.
   .Pp
   Examples:
   .Dl ".Pf $ Ar variable_name"
   .Dl ".Pf . Ar macro_name"
   .Dl ".Pf 0x Ar hex_digits"
   .Pp
   See also
   .Ic \&Ns
   and
   .Ic \&Sm .
   .It Ic \&Po Ar block
   Multi-line version of
   .Ic \&Pq .
   .It Ic \&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
   .Ic \&Sh
   or
   .Ic \&Ss
   macros or before displays
   .Pq Ic \&Bd Ar line
   or lists
   .Pq Ic \&Bl
   unless the
   .Fl compact
   flag is given.
   .It Ic \&Pq Ar line
   Parenthesised enclosure.
   .Pp
   See also
   .Ic \&Po .
   .It Ic \&Qc
   Close quoted context opened by
   .Ic \&Qo .
   .It Ic \&Ql Ar line
   In-line literal display.
   This can be used for complete command invocations and for multi-word
   code examples when an indented display is not desired.
   .Pp
   See also
   .Ic \&Dl
   and
   .Ic \&Bd
   .Fl literal .
   .It Ic \&Qo Ar block
   Multi-line version of
   .Ic \&Qq .
   .It Ic \&Qq Ar line
   Encloses its arguments in
   .Qq typewriter
   double-quotes.
   Consider using
   .Ic \&Dq .
   .Pp
   See also
   .Ic \&Dq ,
   .Ic \&Sq ,
   and
   .Ic \&Qo .
   .It Ic \&Re
   Close an
   .Ic \&Rs
   block.
   Does not have any tail arguments.
   .It Ic \&Rs
   Begin a bibliographic
 .Pq Dq reference  .Pq Dq reference
 block.  Does not have any head arguments.  The block macro may only  block.
 contain  Does not have any head arguments.
 .Sx \&%A ,  The block macro may only contain
 .Sx \&%B ,  .Ic \&%A ,
 .Sx \&%C ,  .Ic \&%B ,
 .Sx \&%D ,  .Ic \&%C ,
 .Sx \&%I ,  .Ic \&%D ,
 .Sx \&%J ,  .Ic \&%I ,
 .Sx \&%N ,  .Ic \&%J ,
 .Sx \&%O ,  .Ic \&%N ,
 .Sx \&%P ,  .Ic \&%O ,
 .Sx \&%Q ,  .Ic \&%P ,
 .Sx \&%R ,  .Ic \&%Q ,
 .Sx \&%T ,  .Ic \&%R ,
   .Ic \&%T ,
   .Ic \&%U ,
 and  and
 .Sx \&%V  .Ic \&%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
 \&.%B Introduction to Automata Theory, Languages, and Computation  \&.%B Introduction to Automata Theory, Languages, and Computation
 \&.%I Addison-Wesley  \&.%I Addison-Wesley
 \&.%C Reading, Massachusettes  \&.%C Reading, Massachusetts
 \&.%D 1979  \&.%D 1979
 \&.Re  \&.Re
 .Ed  .Ed
 .Pp  .Pp
 If an  If an
 .Sx \&Rs  .Ic \&Rs
 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.
 .  .It Ic \&Rv Fl std Op Ar function ...
 .Ss \&Rv  Insert a standard sentence regarding a function call's return value of 0
 .Ss \&Sc  on success and \-1 on error, with the
 .Ss \&Sh  .Va errno
 .Ss \&Sm  libc global variable set on error.
 .Ss \&So  
 .Ss \&Sq  
 .Ss \&Ss  
 .Ss \&St  
 .Ss \&Sx  
 .Ss \&Sy  
 .Ss \&Tn  
 .Ss \&Ud  
 .Ss \&Ux  
 Format the UNIX name.  Accepts no argument.  
 .Pp  .Pp
   If
   .Ar function
   is not specified, the document's name set by
   .Ic \&Nm
   is used.
   Multiple
   .Ar function
   arguments are treated as separate functions.
   .Pp
   See also
   .Ic \&Ex .
   .It Ic \&Sc
   Close single-quoted context opened by
   .Ic \&So .
   .It Ic \&Sh Ar TITLE LINE
   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
   .Ic \&Sx .
   Although this macro is parsed, it should not consist of child node or it
   may not be linked with
   .Ic \&Sx .
   .Pp
   See also
   .Ic \&Pp ,
   .Ic \&Ss ,
   and
   .Ic \&Sx .
   .It Ic \&Sm Op Cm on | off
   Switches the spacing mode for output generated from macros.
   .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.
   .Pp
   When called without an argument, the
   .Ic \&Sm
   macro toggles the spacing mode.
   Using this is not recommended because it makes the code harder to read.
   .It Ic \&So Ar block
   Multi-line version of
   .Ic \&Sq .
   .It Ic \&Sq Ar line
   Encloses its arguments in
   .Sq typewriter
   single-quotes.
   .Pp
   See also
   .Ic \&Dq ,
   .Ic \&Qq ,
   and
   .Ic \&So .
   .It Ic \&Ss Ar Title line
   Begin a new subsection.
   Unlike with
   .Ic \&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
   .Ic \&Sx .
   Although this macro is parsed, it should not consist of child node or it
   may not be linked with
   .Ic \&Sx .
   .Pp
   See also
   .Ic \&Pp ,
   .Ic \&Sh ,
   and
   .Ic \&Sx .
   .It Ic \&St Fl Ns Ar abbreviation
   Replace an abbreviation for a standard with the full form.
   The following standards are recognised.
   Where multiple lines are given without a blank line in between,
   they all refer to the same standard, and using the first form
   is recommended.
   .Bl -tag -width 1n
   .It C language standards
   .Pp
   .Bl -tag -width "-p1003.1g-2000" -compact
   .It \-ansiC
   .St -ansiC
   .It \-ansiC-89
   .St -ansiC-89
   .It \-isoC
   .St -isoC
   .It \-isoC-90
   .St -isoC-90
   .br
   The original C standard.
   .Pp
   .It \-isoC-amd1
   .St -isoC-amd1
   .Pp
   .It \-isoC-tcor1
   .St -isoC-tcor1
   .Pp
   .It \-isoC-tcor2
   .St -isoC-tcor2
   .Pp
   .It \-isoC-99
   .St -isoC-99
   .br
   The second major version of the C language standard.
   .Pp
   .It \-isoC-2011
   .St -isoC-2011
   .br
   The third major version of the C language standard.
   .El
   .It POSIX.1 before the Single UNIX Specification
   .Pp
   .Bl -tag -width "-p1003.1g-2000" -compact
   .It \-p1003.1-88
   .St -p1003.1-88
   .It \-p1003.1
   .St -p1003.1
   .br
   The original POSIX standard, based on ANSI C.
   .Pp
   .It \-p1003.1-90
   .St -p1003.1-90
   .It \-iso9945-1-90
   .St -iso9945-1-90
   .br
   The first update of POSIX.1.
   .Pp
   .It \-p1003.1b-93
   .St -p1003.1b-93
   .It \-p1003.1b
   .St -p1003.1b
   .br
   Real-time extensions.
   .Pp
   .It \-p1003.1c-95
   .St -p1003.1c-95
   .br
   POSIX thread interfaces.
   .Pp
   .It \-p1003.1i-95
   .St -p1003.1i-95
   .br
   Technical Corrigendum.
   .Pp
   .It \-p1003.1-96
   .St -p1003.1-96
   .It \-iso9945-1-96
   .St -iso9945-1-96
   .br
   Includes POSIX.1-1990, 1b, 1c, and 1i.
   .El
   .It X/Open Portability Guide version 4 and related standards
   .Pp
   .Bl -tag -width "-p1003.1g-2000" -compact
   .It \-xpg3
   .St -xpg3
   .br
   An XPG4 precursor, published in 1989.
   .Pp
   .It \-p1003.2
   .St -p1003.2
   .It \-p1003.2-92
   .St -p1003.2-92
   .It \-iso9945-2-93
   .St -iso9945-2-93
   .br
   An XCU4 precursor.
   .Pp
   .It \-p1003.2a-92
   .St -p1003.2a-92
   .br
   Updates to POSIX.2.
   .Pp
   .It \-xpg4
   .St -xpg4
   .br
   Based on POSIX.1 and POSIX.2, published in 1992.
   .El
   .It Single UNIX Specification version 1 and related standards
   .Pp
   .Bl -tag -width "-p1003.1g-2000" -compact
   .It \-susv1
   .St -susv1
   .It \-xpg4.2
   .St -xpg4.2
   .br
   This standard was published in 1994.
   It was used as the basis for UNIX 95 certification.
   The following three refer to parts of it.
   .Pp
   .It \-xsh4.2
   .St -xsh4.2
   .Pp
   .It \-xcurses4.2
   .St -xcurses4.2
   .Pp
   .It \-p1003.1g-2000
   .St -p1003.1g-2000
   .br
   Networking APIs, including sockets.
   .Pp
   .It \-svid4
   .St -svid4 ,
   .br
   Published in 1995.
   .El
   .It Single UNIX Specification version 2 and related standards
   .Pp
   .Bl -tag -width "-p1003.1g-2000" -compact
   .It \-susv2
   .St -susv2
   This Standard was published in 1997
   and is also called X/Open Portability Guide version 5.
   It was used as the basis for UNIX 98 certification.
   The following refer to parts of it.
   .Pp
   .It \-xbd5
   .St -xbd5
   .Pp
   .It \-xsh5
   .St -xsh5
   .Pp
   .It \-xcu5
   .St -xcu5
   .Pp
   .It \-xns5
   .St -xns5
   .It \-xns5.2
   .St -xns5.2
   .El
   .It Single UNIX Specification version 3
   .Pp
   .Bl -tag -width "-p1003.1-2001" -compact
   .It \-p1003.1-2001
   .St -p1003.1-2001
   .It \-susv3
   .St -susv3
   .br
   This standard is based on C99, SUSv2, POSIX.1-1996, 1d, and 1j.
   It is also called X/Open Portability Guide version 6.
   It is used as the basis for UNIX 03 certification.
   .Pp
   .It \-p1003.1-2004
   .St -p1003.1-2004
   .br
   The second and last Technical Corrigendum.
   .El
   .It Single UNIX Specification version 4
   .Pp
   .Bl -tag -width "-p1003.1g-2000" -compact
   .It \-p1003.1-2008
   .St -p1003.1-2008
   .It \-susv4
   .St -susv4
   .br
   This standard is also called
   X/Open Portability Guide version 7.
   .El
   .It Other standards
   .Pp
   .Bl -tag -width "-p1003.1g-2000" -compact
   .It \-ieee754
   .St -ieee754
   .br
   Floating-point arithmetic.
   .Pp
   .It \-iso8601
   .St -iso8601
   .br
   Representation of dates and times, published in 1988.
   .Pp
   .It \-iso8802-3
   .St -iso8802-3
   .br
   Ethernet local area networks.
   .Pp
   .It \-ieee1275-94
   .St -ieee1275-94
   .El
   .El
   .It Ic \&Sx Ar Title line
   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:  Examples:
 .Bd -literal -offset indent  .Dl \&.Sx MANUAL STRUCTURE
 \&.Ux  .Pp
   See also
   .Ic \&Sh
   and
   .Ic \&Ss .
   .It Ic \&Sy Ar word ...
   Request a boldface font.
   .Pp
   This is most often used to indicate importance or seriousness (not to be
   confused with stress emphasis, see
   .Ic \&Em ) .
   When none of the semantic macros fit, it is also adequate for syntax
   elements that have to be given or that appear verbatim.
   .Pp
   Examples:
   .Bd -literal -compact -offset indent
   \&.Sy Warning :
   If
   \&.Sy s
   appears in the owner permissions, set-user-ID mode is set.
   This utility replaces the former
   \&.Sy dumpdir
   program.
 .Ed  .Ed
 .Pp  .Pp
 See also  See also
 .Sx \&At ,  .Ic \&Em ,
 .Sx \&Bsx ,  .Ic \&No ,
 .Sx \&Bx ,  
 .Sx \&Dx ,  
 .Sx \&Fx ,  
 .Sx \&Nx ,  
 and  and
 .Sx \&Ox .  .Ic \&Ql .
 .  .It Ic \&Ta
 .Ss \&Va  Table cell separator in
 .Ss \&Vt  .Ic \&Bl Fl column
 A variable type.  This is also used for indicating global variables in the  lists; can only be used below
 SYNOPSIS section, in which case a variable name is also specified.  Note that  .Ic \&It .
 it accepts  .It Ic \&Tn Ar word ...
   Supported only for compatibility, do not use this in new manuals.
   Even though the macro name
   .Pq Dq tradename
   suggests a semantic function, historic usage is inconsistent, mostly
   using it as a presentation-level macro to request a small caps font.
   .It Ic \&Ud
   Supported only for compatibility, do not use this in new manuals.
   Prints out
   .Dq currently under development.
   .It Ic \&Ux
   Supported only for compatibility, do not use this in new manuals.
   Prints out
   .Dq Ux .
   .It Ic \&Va Oo Ar type Oc Ar identifier ...
   A variable name.
   .Pp
   Examples:
   .Dl \&.Va foo
   .Dl \&.Va const char *bar ;
   .Pp
   For function arguments and parameters, use
   .Ic \&Fa
   instead.
   For declarations of global variables in the
   .Em SYNOPSIS
   section, use
   .Ic \&Vt .
   .It Ic \&Vt Ar type Op Ar identifier
   A variable type.
   .Pp
   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  .Sx Block partial-implicit
 syntax when invoked as the first macro in the SYNOPSIS section, else it  syntax when invoked as the first macro on an input line in the
 accepts ordinary  .Em SYNOPSIS
   section, else it accepts ordinary
 .Sx In-line  .Sx In-line
 syntax.  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  .Pp
 Note that this should not be confused with  
 .Sx \&Ft ,  
 which is used for function return types.  
 .Pp  
 Examples:  Examples:
 .Bd -literal -offset indent  .Dl \&.Vt unsigned char
 \&.Vt unsigned char  .Dl \&.Vt extern const char * const sys_signame[] \&;
 \&.Vt extern const char * const sys_signame[] ;  
 .Ed  
 .Pp  .Pp
   For parameters in function prototypes, use
   .Ic \&Fa
   instead, for function return types
   .Ic \&Ft ,
   and for variable names outside the
   .Em SYNOPSIS
   section
   .Ic \&Va ,
   even when including a type with the name.
 See also  See also
 .Sx \&Ft  .Sx MANUAL STRUCTURE .
 and  .It Ic \&Xc
 .Sx \&Va .  
 .  
 .Ss \&Xc  
 Close a scope opened by  Close a scope opened by
 .Sx \&Xo .  .Ic \&Xo .
 .  .It Ic \&Xo Ar block
 .Ss \&Xo  Extend the header of an
 Open an extension scope.  This macro originally existed to extend the  .Ic \&It
 9-argument limit of troff; since this limit has been lifted, the macro  macro or the body of a partial-implicit block macro
 has been deprecated.  beyond the end of the input line.
 .  This macro originally existed to work around the 9-argument limit
 .Ss \&Xr  of historic
   .Xr roff 7 .
   .It Ic \&Xr Ar name section
 Link to another manual  Link to another manual
 .Pq Qq cross-reference .  .Pq Qq cross-reference .
 Its calling syntax is  
 .Pp  .Pp
 .D1 \. Ns Sx \&Xr Cm name section  Cross reference the
   .Ar name
   and
   .Ar section
   number of another man page.
 .Pp  .Pp
   Examples:
   .Dl \&.Xr mandoc 1
   .Dl \&.Xr mandoc 1 \&;
   .Dl \&.Xr mandoc 1 \&Ns s behaviour
   .El
   .Sh MACRO SYNTAX
   The syntax of a macro depends on its classification.
   In this section,
   .Sq \-arg
   refers to macro arguments, which may be followed by zero or more
   .Sq parm
   parameters;
   .Sq \&Yo
   opens the scope of a macro; and if specified,
   .Sq \&Yc
   closes it out.
   .Pp
 The  The
 .Cm name  .Em Callable
   column indicates that the macro may also be called by passing its name
   as an argument to another macro.
   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
   produces
   .Sq Fl \&Sh .
   .Pp
   The
   .Em Parsed
   column indicates whether the macro may call other macros by receiving
   their names as arguments.
   If a macro is not parsed but the name of another macro appears
   as an argument, it is interpreted as opaque text.
   .Pp
   The
   .Em Scope
   column, if applicable, describes closure rules.
   .Ss Block full-explicit
   Multi-line scope closed by an explicit closing macro.
   All macros contains bodies; only
   .Ic \s&Bf
 and  and
 .Cm section  .Pq optionally
 are the name and section of the linked manual.  If  .Ic \&Bl
 .Cm section  contain a head.
 is followed by non-punctuation, an  .Bd -literal -offset indent
 .Sx \&Ns  \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
 is inserted into the token stream.  This behaviour is for compatibility  \(lBbody...\(rB
 with  \&.Yc
 .Xr groff 1 .  .Ed
   .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXX" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
   .It Ic \&Bd  Ta    \&No     Ta    \&No     Ta    closed by Ic \&Ed
   .It Ic \&Bf  Ta    \&No     Ta    \&No     Ta    closed by Ic \&Ef
   .It Ic \&Bk  Ta    \&No     Ta    \&No     Ta    closed by Ic \&Ek
   .It Ic \&Bl  Ta    \&No     Ta    \&No     Ta    closed by Ic \&El
   .It Ic \&Ed  Ta    \&No     Ta    \&No     Ta    opened by Ic \&Bd
   .It Ic \&Ef  Ta    \&No     Ta    \&No     Ta    opened by Ic \&Bf
   .It Ic \&Ek  Ta    \&No     Ta    \&No     Ta    opened by Ic \&Bk
   .It Ic \&El  Ta    \&No     Ta    \&No     Ta    opened by Ic \&Bl
   .El
   .Ss Block full-implicit
   Multi-line scope closed by end-of-file or implicitly by another macro.
   All macros have bodies; some
   .Po
   .Ic \&It Fl bullet ,
   .Fl hyphen ,
   .Fl dash ,
   .Fl enum ,
   .Fl item
   .Pc
   don't have heads; only one
   .Po
   .Ic \&It
   in
   .Ic \&Bl Fl column
   .Pc
   has multiple heads.
   .Bd -literal -offset indent
   \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead... \(lBTa head...\(rB\(rB
   \(lBbody...\(rB
   .Ed
   .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXXXXXXXXX" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
   .It Ic \&It Ta \&No Ta Yes  Ta closed by Ic \&It , Ic \&El
   .It Ic \&Nd Ta \&No Ta \&No Ta closed by Ic \&Sh
   .It Ic \&Nm Ta \&No Ta Yes  Ta closed by Ic \&Nm , Ic \&Sh , Ic \&Ss
   .It Ic \&Sh Ta \&No Ta Yes  Ta closed by Ic \&Sh
   .It Ic \&Ss Ta \&No Ta Yes  Ta closed by Ic \&Sh , Ic \&Ss
   .El
 .Pp  .Pp
 Examples:  Note that the
   .Ic \&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
   Like block full-explicit, but also with single-line scope.
   Each has at least a body and, in limited circumstances, a head
   .Po
   .Ic \&Fo ,
   .Ic \&Eo
   .Pc
   and/or tail
   .Pq Ic \&Ec .
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Xr mandoc 1  \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
 \&.Xr mandoc 1 ;  \(lBbody...\(rB
 \&.Xr mandoc 1 s behaviour  \&.Yc \(lBtail...\(rB
   
   \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB \
   \(lBbody...\(rB \&Yc \(lBtail...\(rB
 .Ed  .Ed
 .  .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXX" -offset indent
 .Ss \&br  .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
 .Ss \&sp  .It Ic \&Ac  Ta    Yes      Ta    Yes      Ta    opened by Ic \&Ao
 .  .It Ic \&Ao  Ta    Yes      Ta    Yes      Ta    closed by Ic \&Ac
 .  .It Ic \&Bc  Ta    Yes      Ta    Yes      Ta    closed by Ic \&Bo
   .It Ic \&Bo  Ta    Yes      Ta    Yes      Ta    opened by Ic \&Bc
   .It Ic \&Brc Ta    Yes      Ta    Yes      Ta    opened by Ic \&Bro
   .It Ic \&Bro Ta    Yes      Ta    Yes      Ta    closed by Ic \&Brc
   .It Ic \&Dc  Ta    Yes      Ta    Yes      Ta    opened by Ic \&Do
   .It Ic \&Do  Ta    Yes      Ta    Yes      Ta    closed by Ic \&Dc
   .It Ic \&Ec  Ta    Yes      Ta    Yes      Ta    opened by Ic \&Eo
   .It Ic \&Eo  Ta    Yes      Ta    Yes      Ta    closed by Ic \&Ec
   .It Ic \&Fc  Ta    Yes      Ta    Yes      Ta    opened by Ic \&Fo
   .It Ic \&Fo  Ta    \&No     Ta    \&No     Ta    closed by Ic \&Fc
   .It Ic \&Oc  Ta    Yes      Ta    Yes      Ta    closed by Ic \&Oo
   .It Ic \&Oo  Ta    Yes      Ta    Yes      Ta    opened by Ic \&Oc
   .It Ic \&Pc  Ta    Yes      Ta    Yes      Ta    closed by Ic \&Po
   .It Ic \&Po  Ta    Yes      Ta    Yes      Ta    opened by Ic \&Pc
   .It Ic \&Qc  Ta    Yes      Ta    Yes      Ta    opened by Ic \&Oo
   .It Ic \&Qo  Ta    Yes      Ta    Yes      Ta    closed by Ic \&Oc
   .It Ic \&Re  Ta    \&No     Ta    \&No     Ta    opened by Ic \&Rs
   .It Ic \&Rs  Ta    \&No     Ta    \&No     Ta    closed by Ic \&Re
   .It Ic \&Sc  Ta    Yes      Ta    Yes      Ta    opened by Ic \&So
   .It Ic \&So  Ta    Yes      Ta    Yes      Ta    closed by Ic \&Sc
   .It Ic \&Xc  Ta    Yes      Ta    Yes      Ta    opened by Ic \&Xo
   .It Ic \&Xo  Ta    Yes      Ta    Yes      Ta    closed by Ic \&Xc
   .El
   .Ss Block partial-implicit
   Like block full-implicit, but with single-line scope closed by the
   end of the line.
   .Bd -literal -offset indent
   \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBbody...\(rB \(lBres...\(rB
   .Ed
   .Bl -column "MacroX" "CallableX" "ParsedX" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed
   .It Ic \&Aq  Ta    Yes      Ta    Yes
   .It Ic \&Bq  Ta    Yes      Ta    Yes
   .It Ic \&Brq Ta    Yes      Ta    Yes
   .It Ic \&D1  Ta    \&No     Ta    \&Yes
   .It Ic \&Dl  Ta    \&No     Ta    Yes
   .It Ic \&Dq  Ta    Yes      Ta    Yes
   .It Ic \&En  Ta    Yes      Ta    Yes
   .It Ic \&Op  Ta    Yes      Ta    Yes
   .It Ic \&Pq  Ta    Yes      Ta    Yes
   .It Ic \&Ql  Ta    Yes      Ta    Yes
   .It Ic \&Qq  Ta    Yes      Ta    Yes
   .It Ic \&Sq  Ta    Yes      Ta    Yes
   .It Ic \&Vt  Ta    Yes      Ta    Yes
   .El
   .Pp
   Note that the
   .Ic \&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
   .Ic \&Ta
   macro can only be used below
   .Ic \&It
   in
   .Ic \&Bl Fl column
   lists.
   It delimits blocks representing table cells;
   these blocks have bodies, but no heads.
   .Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXX" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
   .It Ic \&Ta  Ta    Yes      Ta    Yes    Ta closed by Ic \&Ta , Ic \&It
   .El
   .Ss In-line
   Closed by the end of the line, fixed argument lengths,
   and/or subsequent macros.
   In-line macros have only text children.
   If a number (or inequality) of arguments is
   .Pq n ,
   then the macro accepts an arbitrary number of arguments.
   .Bd -literal -offset indent
   \&.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 arg0 arg1 argN
   .Ed
   .Bl -column "MacroX" "CallableX" "ParsedX" "Arguments" -offset indent
   .It Em Macro Ta Em Callable Ta Em Parsed Ta Em Arguments
   .It Ic \&%A  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%B  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%C  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%D  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%I  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%J  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%N  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%O  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%P  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%Q  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%R  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%T  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%U  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&%V  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&Ad  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&An  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Ap  Ta    Yes      Ta    Yes      Ta    0
   .It Ic \&Ar  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&At  Ta    Yes      Ta    Yes      Ta    1
   .It Ic \&Bsx Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Bt  Ta    \&No     Ta    \&No     Ta    0
   .It Ic \&Bx  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Cd  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Cm  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Db  Ta    \&No     Ta    \&No     Ta    1
   .It Ic \&Dd  Ta    \&No     Ta    \&No     Ta    n
   .It Ic \&Dt  Ta    \&No     Ta    \&No     Ta    n
   .It Ic \&Dv  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Dx  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Em  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Er  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Es  Ta    Yes      Ta    Yes      Ta    2
   .It Ic \&Ev  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Ex  Ta    \&No     Ta    \&No     Ta    n
   .It Ic \&Fa  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Fd  Ta    \&No     Ta    \&No     Ta    >0
   .It Ic \&Fl  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Fn  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Fr  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Ft  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Fx  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Hf  Ta    \&No     Ta    \&No     Ta    n
   .It Ic \&Ic  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&In  Ta    \&No     Ta    \&No     Ta    1
   .It Ic \&Lb  Ta    \&No     Ta    \&No     Ta    1
   .It Ic \&Li  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Lk  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Lp  Ta    \&No     Ta    \&No     Ta    0
   .It Ic \&Ms  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Mt  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Nm  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&No  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Ns  Ta    Yes      Ta    Yes      Ta    0
   .It Ic \&Nx  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Os  Ta    \&No     Ta    \&No     Ta    n
   .It Ic \&Ot  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Ox  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Pa  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Pf  Ta    Yes      Ta    Yes      Ta    1
   .It Ic \&Pp  Ta    \&No     Ta    \&No     Ta    0
   .It Ic \&Rv  Ta    \&No     Ta    \&No     Ta    n
   .It Ic \&Sm  Ta    \&No     Ta    \&No     Ta    <2
   .It Ic \&St  Ta    \&No     Ta    Yes      Ta    1
   .It Ic \&Sx  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Sy  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Tn  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Ud  Ta    \&No     Ta    \&No     Ta    0
   .It Ic \&Ux  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Va  Ta    Yes      Ta    Yes      Ta    n
   .It Ic \&Vt  Ta    Yes      Ta    Yes      Ta    >0
   .It Ic \&Xr  Ta    Yes      Ta    Yes      Ta    2
   .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.
   Spacing is suppressed after opening delimiters
   and before closing delimiters.
   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, which does not suppress spacing:
   .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.
   .Pp
   Appending a zero-width space
   .Pq Sq \e&
   to the end of an input line is also useful to prevent the interpretation
   of a trailing period, exclamation or question mark as the end of a
   sentence, for example when an abbreviation happens to occur
   at the end of a text or macro input line.
   .Ss Font handling
   In
   .Nm
   documents, usage of semantic markup is recommended in order to have
   proper fonts automatically selected; only when no fitting semantic markup
   is available, consider falling back to
   .Sx Physical markup
   macros.
   Whenever any
   .Nm
   macro switches the
   .Xr roff 7
   font mode, it will automatically restore the previous font when exiting
   its scope.
   Manually switching the font using the
   .Xr roff 7
   .Ql \ef
   font escape sequences is never required.
 .Sh COMPATIBILITY  .Sh COMPATIBILITY
 This section documents compatibility with other roff implementations, at  This section provides an incomplete list of compatibility issues
 this time limited to  between mandoc and GNU troff
 .Xr groff 1 .  .Pq Qq groff .
 The term  
 .Qq historic groff  
 refers to those versions before the  
 .Pa doc.tmac  
 file re-write  
 .Pq somewhere between 1.15 and 1.19 .  
 .  
 .Pp  .Pp
   The following problematic behaviour is found in groff:
   .Pp
 .Bl -dash -compact  .Bl -dash -compact
 .It  .It
 The comment syntax  .Ic \&Dd
 .Sq \e."  with non-standard arguments behaves very strangely.
 is no longer accepted.  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
 In  .Ic \&Lk
 .Xr groff 1 ,  only accepts a single link-name argument; the remainder is misformatted.
 the  
 .Sx \&Pa  
 macro does not format its arguments when used in the FILES section under  
 certain list types.  This irregular behaviour has been discontinued.  
 .It  .It
 Historic  .Ic \&Pa
 .Xr groff 1  does not format its arguments when used in the FILES section under
 does not print a dash for empty  certain list types.
 .Sx \&Fl  
 arguments.  This behaviour has been discontinued.  
 .It  .It
 .Xr groff 1  .Ic \&Ta
 behaves strangely (even between versions) when specifying  can only be called by other macros, but not at the beginning of a line.
   .It
   .Ic \&%C
   is not implemented (up to and including groff-1.22.2).
   .It
 .Sq \ef  .Sq \ef
 escapes within line-macro scopes.  These aberrations have been  .Pq font face
 normalised.  and
   .Sq \eF
   .Pq font family face
   .Sx Text Decoration
   escapes behave irregularly when specified within line-macro scopes.
 .It  .It
 Negative scaling units are now truncated to zero instead of creating  Negative scaling units return to prior lines.
 interesting conditions, such as with  Instead, mandoc truncates them to zero.
 .Sx \&sp  .El
 .Fl 1i .  .Pp
 Furthermore, the  The following features are unimplemented in mandoc:
 .Sq f  .Pp
 scaling unit, while accepted, is rendered as the default unit.  .Bl -dash -compact
 .It  .It
 In quoted literals, groff allowed pair-wise double-quotes to produce a  .Ic \&Bd Fl file Ar file
 standalone double-quote in formatted output.  This idiosyncratic  is unsupported for security reasons.
 behaviour is no longer applicable.  
 .It  .It
 Display types  .Ic \&Bd
 .Sx \&Bd  
 .Fl center  
 and  
 .Fl right  
 are aliases for  
 .Fl left .  
 The  
 .Fl file Ar file  
 argument is ignored.  Since text is not right-justified,  
 .Fl ragged  
 and  
 .Fl filled  .Fl filled
 are aliases, as are  does not adjust the right margin, but is an alias for
   .Ic \&Bd
   .Fl ragged .
   .It
   .Ic \&Bd
 .Fl literal  .Fl literal
 and  does not use a literal font, but is an alias for
   .Ic \&Bd
 .Fl unfilled .  .Fl unfilled .
 .It  .It
 Blocks of whitespace are stripped from both macro and free-form text  .Ic \&Bd
 lines (except when in literal mode), while groff would retain whitespace  .Fl offset Cm center
 in free-form text lines.  and
 .It  .Fl offset Cm right
 Historic groff has many un-callable macros.  Most of these (excluding  don't work.
 some block-level macros) are now callable, conforming to the  Groff does not implement centered and flush-right rendering either,
 non-historic groff version.  but produces large indentations.
 .It  
 The vertical bar  
 .Sq \(ba  
 made historic groff  
 .Qq go orbital  
 but is a proper delimiter in this implementation.  
 .It  
 .Sx \&It  
 .Fl nested  
 is assumed for all lists (it wasn't in historic groff): any list may be  
 nested and  
 .Fl enum  
 lists will restart the sequence only for the sub-list.  
 .It  
 Some manuals use  
 .Sx \&Li  
 incorrectly by following it with a reserved character and expecting the  
 delimiter to render.  This is not supported.  
 .It  
 In groff, the  
 .Sx \&Fo  
 macro only produces the first parameter.  This is no longer the case.  
 .El  .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
   .Pp
   The web page
   .Lk http://mandoc.bsd.lv/mdoc/ "extended documentation for the mdoc language"
   provides a few tutorial-style pages for beginners, an extensive style
   guide for advanced authors, and an alphabetic index helping to choose
   the best macros for various kinds of content.
   .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 Mt 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  
 .\" .  
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  Added in v.1.279
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