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Diff for /mandoc/mdoc.7 between version 1.42 and 1.93

version 1.42, 2009/07/13 07:23:07 version 1.93, 2010/04/07 19:37:54
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 .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN  .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"  .\"
 .Dd $Mdocdate$  .Dd $Mdocdate$
 .Dt MDOC 7  .Dt MDOC 7
 .Os  .Os
 .\" SECTION  .
   .
 .Sh NAME  .Sh NAME
 .Nm mdoc  .Nm mdoc
 .Nd mdoc language reference  .Nd mdoc language reference
 .\" SECTION  .
   .
 .Sh DESCRIPTION  .Sh DESCRIPTION
 The  The
 .Nm mdoc  .Nm mdoc
 language is used to format  language is used to format
 .Bx  .Bx
 .Ux  .Ux
 manuals.  In this reference document, we describe the syntax and  manuals.  In this reference document, we describe its syntax, structure,
 structure of the  and usage.  Our reference implementation is mandoc; the
 .Nm  
 language.  Our reference implementation is  
 .Xr mandoc 1 .  
 The  
 .Sx COMPATIBILITY  .Sx COMPATIBILITY
 section describes compatibility with  section describes compatibility with other troff \-mdoc implementations.
 .Xr groff 1 .  .
 .\" PARAGRAPH  
 .Pp  .Pp
 An  An
 .Nm  .Nm
 document follows simple rules:  lines beginning with the control  document follows simple rules:  lines beginning with the control
 character  character
 .Sq \.  .Sq \.
 are parsed for macros.  Other lines are interpreted within the scope of  are parsed for macros.  Other lines are interpreted within the scope of
 prior macros:  prior macros:
Line 50  prior macros:
Line 47  prior macros:
 \&.Sh Macro lines change control state.  \&.Sh Macro lines change control state.
 Other lines are interpreted within the current state.  Other lines are interpreted within the current state.
 .Ed  .Ed
 .\" SECTION  .
 .Sh INPUT ENCODING  .
   .Sh LANGUAGE SYNTAX
 .Nm  .Nm
 documents may contain only graphable 7-bit ASCII characters, the space  documents may contain only graphable 7-bit ASCII characters, the space
 character  character, and, in certain circumstances, the tab character.  All
 .Sq \  ,  manuals must have
 and, in certain circumstances, the tab character  .Ux
 .Sq \et .  line terminators.
 All manuals must have  .
 .Sq \en  .
 line termination.  
 .Pp  
 The only time a blank line is acceptable is within  
 the context of  
 .Sq \&.Bd \-literal  
 or  
 .Sq \&.Bd \-unfilled .  
 .Pp  
 Tab characters  
 .Pq \et  
 are only acceptable when delimiting  
 .Sq \&.Bl \-column  
 and in  
 .Sq \&.Bd \-literal  
 or  
 .Sq \&.Bd \-unfilled  
 contexts.  
 .\" SUB-SECTION  
 .Ss Comments  .Ss Comments
 Anything following a  Text following a
 .Sq \e"  .Sq \e" ,
 delimiter is considered a comment (unless the  whether in a macro or free-form text line, is ignored to the end of
 .Sq \e  line.  A macro line with only a control character and comment escape,
 itself has been escaped) and is ignored to the end of line.  .Sq \&.\e" ,
 Furthermore, a macro line with only a control character  is also ignored.  Macro lines with only a control charater and optionally
 .Sq \. ,  whitespace are stripped from input.
 optionally followed by whitespace, is ignored.  .
 .\" SUB-SECTION  .
 .Ss Reserved Characters  .Ss Reserved Characters
 Within a macro line, the following characters are reserved:  Within a macro line, the following characters are reserved:
   .Pp
 .Bl -tag -width Ds -offset indent -compact  .Bl -tag -width Ds -offset indent -compact
 .It \&.  .It \&.
 .Pq period  .Pq period
Line 110  Within a macro line, the following characters are rese
Line 91  Within a macro line, the following characters are rese
 .It \&?  .It \&?
 .Pq question  .Pq question
 .It \&!  .It \&!
 .Pq exclamation  .Pq exclamation
 .It \&|  .It \&|
 .Pq vertical bar  .Pq vertical bar
 .El  .El
 .\" PARAGRAPH  .
 .Pp  .Pp
 Use of reserved characters is described in  Use of reserved characters is described in
 .Sx Closure .  .Sx MACRO SYNTAX .
 For general non-reserved use, characters must either be escaped with a  For general use in macro lines, these characters must either be escaped
 non-breaking space  with a non-breaking space
 .Pq Sq \e&  .Pq Sq \e&
 or, if applicable, an appropriate escape-sequence used.  or, if applicable, an appropriate escape sequence used.
 .\" SUB-SECTION  .
   .
 .Ss Special Characters  .Ss Special Characters
 Special character sequences begin with the escape character  Special characters may occur in both macro and free-form lines.
   Sequences begin with the escape character
 .Sq \e  .Sq \e
 followed by either an open-parenthesis  followed by either an open-parenthesis
 .Sq \&(  .Sq \&(
 for two-character sequences; an open-bracket  for two-character sequences; an open-bracket
 .Sq \&[  .Sq \&[
 for n-character sequences (terminated at a close-bracket  for n-character sequences (terminated at a close-bracket
 .Sq \&] ) ;  .Sq \&] ) ;
 or a single one-character sequence.  or a single one-character sequence.  See
   .Xr mandoc_char 7
   for a complete list.  Examples include
   .Sq \e(em
   .Pq em-dash
   and
   .Sq \ee
   .Pq back-slash .
   .
   .
   .Ss Text Decoration
   Terms may be text-decorated using the
   .Sq \ef
   escape followed by an indicator: B (bold), I, (italic), R (Roman), or P
   (revert to previous mode):
 .Pp  .Pp
 Characters may alternatively be escaped by a slash-asterisk,  .D1 \efBbold\efR \efIitalic\efP
 .Sq \e* ,  
 with the same combinations as described above.  
 .Pp  .Pp
 Terms may also be text-decorated using the  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  .Sq \ef
 escape followed by a text-decoration letter: B (bold), I, (italic), or P  are only valid within the font scope of the macro.  If
 and R (Roman, or reset).  This form is not recommended.  .Sq \ef
 .\" SUB-SECTION  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  .Ss Whitespace
 Unless in literal mode or specifically escaped, consecutive blocks of  In non-literal free-form lines, consecutive blocks of whitespace are
 whitespace are pruned from input.  These are later re-added, if  pruned from input and added later in the output filter, if applicable:
 applicable, by a front-end utility such as  .Bd -literal -offset indent
 .Xr mandoc 1 .  These     spaces   are    pruned       from    input.
 .\" SECTION  \&.Bd \-literal
 .Sh STRUCTURE  These         are              not.
 Each  \&.Ed
 .Nm  .Ed
 document must begin with the document prologue, containing, in order,  .
 .Sq \&.Dd ,  .Pp
 .Sq \&.Dt ,  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  and
 .Sq \&.Os .  .Sq fg" .
 Following these, the document body must begin with the NAME section  Note that any quoted term, be it argument or macro, is indiscriminately
 containing at least one  considered literal text.  Thus, the following produces
 .Sq \&.Nm  .Sq \&Em a :
 followed by a  .Bd -literal -offset indent
 .Sq \&.Nd  \&.Em "Em a"
 macro.  .Ed
   .
 .Pp  .Pp
 At least one free-form or macro line must follow this prologue.  In free-form mode, quotes are regarded as opaque text.
 .\"  .
 .Ss Classification  .Ss Dates
 Macros are classified by their scope rules.  Some macros are allowed to  There are several macros in
 deviate from their classifications to preserve backward-compatibility  .Nm
 with old macro combinations still found in the manual corpus.  These are  that require a date argument.  The canonical form for dates is the
 specifically noted on a per-macro basis.  American format:
 .\" SUB-SECTION  
 .Ss Scope  
 .Bl -inset  
 .\" LIST-ITEM  
 .It Em Block  
 macros enclose other block macros, in-line macros or text, and  
 may span multiple lines.  
 .Bl -inset -offset indent  
 .\" LIST-ITEM  
 .It Em Full-block  
 macros always span multiple lines.  They consist of zero or  
 more  
 .Qq heads ,  
 subsequent macros or text on the same line following invocation; an  
 optional  
 .Qq body ,  
 which spans subsequent lines of text or macros; and an optional  
 .Qq tail ,  
 macros or text on the same line following closure.  
 .\" LIST-ITEM  
 .It Em Partial-block  
 macros may span multiple lines.  They consists of a optional  
 .Qq head ,  
 text immediately following invocation; always a  
 .Qq body ,  
 text or macros following the head on the same and subsequent lines; and  
 optionally a  
 .Qq tail ,  
 text immediately following closure.  
 .\" LIST-ITEM  
 .It Em In-line  
 macros may only enclose text and span at most a single line.  
 .El  
 .El  
 .\" SUB-SECTION  
 .Ss Closure  
 Closure of a macro's scope depends first on its classification, then  
 on whether it's parsable.  In this table,  
 .Sq BFE  
 refers to block full-explicit and so on.  
 .\" PARAGRAPH  
 .Pp  .Pp
 .Bl -tag -width 12n -offset indent -compact  .D1 Cm Month Day , Year
 .It BPE , BFE  
 corresponding explicit closure macro  
 .It BFI  
 end-of-file or a corresponding implicit closure macro  
 .It BPI  
 end-of-line (body may be closed by >0 space-separated  
 .Sx Reserved Characters ,  
 although block scope will still be open)  
 .It INL  
 end-of-line  
 .El  
 .\" PARAGRAPH  
 .Pp  .Pp
 If a macro (block or in-line) is parsable, it may also be closed out by  The
 one of the following scenarios (unless specifically noted otherwise):  .Cm Day
 .\" PARAGRAPH  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  .Pp
 .Bl -dash -offset indent -compact  Reduced form dates are broken-down canonical form dates:
 .It  .Pp
 a sequence of >0 space-separated  .D1 Cm Month , Year
 .Sx Reserved Characters ,  .D1 Cm Year
 .It  .Pp
 another macro,  Some examples of valid dates follow:
 .It  .Pp
 end-of-line, or  .D1 "May, 2009" Pq reduced form
 .It  .D1 "2009" Pq reduced form
 completion of a set number of arguments.  .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  .El
 .\" PARAGRAPH  
 .Pp  .Pp
 If >0 space-separated  Using anything other than
 .Sx Reserved Characters  .Sq m ,
 are followed by non-reserved characters, the behaviour differs per  .Sq n ,
 macro.  In general, scope of the macro is closed and re-opened:  .Sq u ,
 subsequent tokens are interpreted as if the scope had just been opened.  or
 In other circumstances, scope is simply closed out.  .Sq v
 .\" SECTION  is necessarily non-portable across output media.  See
 .Sh SYNTAX  .Sx COMPATIBILITY .
 Macros are two or three characters in length.  The syntax of macro  .
 invocation depends on its classification.  .
 .Qq \-arg  .Sh MANUAL STRUCTURE
 refers to the macro arguments (which may contain zero or more values).  A well-formed
 In these illustrations,  .Nm
 .Sq \&.Yo  document consists of a document prologue followed by one or more
 opens the scope of a macro, and if specified,  sections.
 .Sq \&.Yc  
 closes it out (closure may be implicit at end-of-line or end-of-file).  
 .\" PARAGRAPH  
 .Pp  .Pp
 Block full-explicit (may contain head, body, tail).  The prologue, which consists of (in order) the
   .Sx \&Dd ,
   .Sx \&Dt ,
   and
   .Sx \&Os
   macros, is required for every document.
   .Pp
   The first section (sections are denoted by
   .Sx \&Sh )
   must be the NAME section, consisting of at least one
   .Sx \&Nm
   followed by
   .Sx \&Nd .
   .Pp
   Following that, convention dictates specifying at least the SYNOPSIS and
   DESCRIPTION sections, although this varies between manual sections.
   .Pp
   The following is a well-formed skeleton
   .Nm
   file:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBhead...\(rB  \&.Dd $\&Mdocdate$
 \(lBbody...\(rB  \&.Dt mdoc 7
 \&.Yc \(lBtail...\(rB  \&.Os
   \&.
   \&.Sh NAME
   \&.Nm foo
   \&.Nd a description goes here
   \&.\e\*q The next is for sections 2 & 3 only.
   \&.\e\*q .Sh LIBRARY
   \&.
   \&.Sh SYNOPSIS
   \&.Nm foo
   \&.Op Fl options
   \&.Ar
   \&.
   \&.Sh DESCRIPTION
   The
   \&.Nm
   utility processes files ...
   \&.\e\*q .Sh IMPLEMENTATION NOTES
   \&.\e\*q The next is for sections 1 & 8 only.
   \&.\e\*q .Sh EXIT STATUS
   \&.\e\*q The next is for sections 2, 3, & 9 only.
   \&.\e\*q .Sh RETURN VALUES
   \&.\e\*q The next is for sections 1, 6, 7, & 8 only.
   \&.\e\*q .Sh ENVIRONMENT
   \&.\e\*q .Sh FILES
   \&.\e\*q .Sh EXAMPLES
   \&.\e\*q The next is for sections 1, 4, 6, 7, & 8 only.
   \&.\e\*q .Sh DIAGNOSTICS
   \&.\e\*q The next is for sections 2, 3, & 9 only.
   \&.\e\*q .Sh ERRORS
   \&.\e\*q .Sh SEE ALSO
   \&.\e\*q .Xr foobar 1
   \&.\e\*q .Sh STANDARDS
   \&.\e\*q .Sh HISTORY
   \&.\e\*q .Sh AUTHORS
   \&.\e\*q .Sh CAVEATS
   \&.\e\*q .Sh BUGS
   \&.\e\*q .Sh SECURITY CONSIDERATIONS
 .Ed  .Ed
 .\" PARAGRAPH  
 .Pp  .Pp
 Block full-implicit (may contain zero or more heads, body, no tail).  The sections in a
   .Nm
   document are conventionally ordered as they appear above.  Sections
   should be composed as follows:
   .Bl -ohang -offset Ds
   .It Em NAME
   The name(s) and a short description of the documented material.  The
   syntax for this as follows:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBhead... \(lBTa head...\(rB\(rB  \&.Nm name0
 \(lBbody...\(rB  \&.Nm name1
 \&.Yc  \&.Nm name2
   \&.Nd a short description
 .Ed  .Ed
 .\" PARAGRAPH  
 .Pp  .Pp
 Block partial-explicit (may contain head, multi-line body, tail).  The
   .Sx \&Nm
   macro(s) must precede the
   .Sx \&Nd
   macro.
   .Pp
   See
   .Sx \&Nm
   and
   .Sx \&Nd .
   .
   .It Em LIBRARY
   The name of the library containing the documented material, which is
   assumed to be a function in a section 2 or 3 manual.  The syntax for
   this is as follows:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBhead...\(rB  \&.Lb libarm
 \(lBbody...\(rB  
 \&.Yc \(lBtail...\(rB  
   
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBhead...\(rB \  
 \(lBbody...\(rB \&Yc \(lBtail...\(rB  
 .Ed  .Ed
 .\" PARAGRAPH  
 .Pp  .Pp
 Block partial-implicit (no head, body, no tail).  Note that the body  See
 section may be followed by zero or more  .Sx \&Lb .
 .Sx Reserved Words .  .
 These are in the block scope, but not in the body scope.  .It Em SYNOPSIS
   Documents the utility invocation syntax, function call syntax, or device
   configuration.
   .Pp
   For the first, utilities (sections 1, 6, and 8), this is
   generally structured as follows:
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Yo \(lB\-arg \(lBval...\(rB\(rB \(lBbody...\(rB \(lBreserved...\(rB  \&.Nm foo
   \&.Op Fl v
   \&.Op Fl o Ar file
   \&.Op Ar
   \&.Nm bar
   \&.Op Fl v
   \&.Op Fl o Ar file
   \&.Op Ar
 .Ed  .Ed
 .\" PARAGRAPH  
 .Pp  .Pp
 In-lines have \(>=0 scoped arguments.  For the second, function calls (sections 2, 3, 9):
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Yy \(lB\-arg \(lBval...\(rB\(rB \(lBargs...\(rB  \&.Vt extern const char *global;
   \&.In header.h
 \&.Yy \(lB\-arg \(lBval...\(rB\(rB arg0 arg1 argN  \&.Ft "char *"
   \&.Fn foo "const char *src"
   \&.Ft "char *"
   \&.Fn bar "const char *src"
 .Ed  .Ed
 .\" SECTION  
 .Sh MACROS  
 This section contains a complete list of all  
 .Nm  
 macros, arranged by classification.  A  
 .Qq callable  
 macro is invoked subsequent to the initial macro-line macro.  A  
 .Qq parsable  
 macro may be followed by further (ostensibly callable) macros.  
 .\" SUB-SECTION  
 .Ss Block full-implicit  
 The head of these macros follows invocation; the body is the content of  
 subsequent lines prior to closure.  None of these macros have tails;  
 some  
 .Po  
 .Sq \&.It \-bullet ,  
 .Sq \-hyphen ,  
 .Sq \-dash ,  
 .Sq \-enum ,  
 .Sq \-item  
 .Pc  
 don't have heads.  
 .Pp  .Pp
 .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsableX" "Closing"  And for the third, configurations (section 4):
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Closing  .Bd -literal -offset indent
 .It \&.Nd    Ta    \&No    Ta    \&No    Ta    \&.Sh  \&.Cd \*qit* at isa? port 0x2e\*q
 .It \&.Sh    Ta    \&No    Ta    \&No    Ta    \&.Sh  \&.Cd \*qit* at isa? port 0x4e\*q
 .It \&.Ss    Ta    \&No    Ta    \&No    Ta    \&.Sh, \&.Ss  .Ed
 .It \&.It    Ta    \&No    Ta    Yes     Ta    \&.It, \&.El  .Pp
   Manuals not in these sections generally don't need a
   .Em SYNOPSIS .
   .Pp
   See
   .Sx \&Op ,
   .Sx \&Cd ,
   .Sx \&Fn ,
   .Sx \&Ft ,
   and
   .Sx \&Vt .
   .
   .It Em DESCRIPTION
   This expands upon the brief, one-line description in
   .Em NAME .
   It usually contains a break-down of the options (if documenting a
   command), such as:
   .Bd -literal -offset indent
   The arguments are as follows:
   \&.Bl \-tag \-width Ds
   \&.It Fl v
   Print verbose information.
   \&.El
   .Ed
   .Pp
   Manuals not documenting a command won't include the above fragment.
   .
   .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
   See
   .Sx \&Ex .
   .
   .It Em RETURN VALUES
   This section is the dual of
   .Em EXIT STATUS ,
   which is used for commands.  It documents the return values of functions
   in sections 2, 3, and 9.
   .Pp
   See
   .Sx \&Rv .
   .
   .It Em ENVIRONMENT
   Documents any usages of environment variables, e.g.,
   .Xr environ 7 .
   .Pp
   See
   .Sx \&Ev .
   .
   .It Em FILES
   Documents files used.  It's helpful to document both the file and a
   short description of how the file is used (created, modified, etc.).
   .Pp
   See
   .Sx \&Pa .
   .
   .It Em EXAMPLES
   Example usages.  This often contains snippets of well-formed,
   well-tested invocations.  Make doubly sure that your examples work
   properly!
   .
   .It Em DIAGNOSTICS
   Documents error conditions.  This is most useful in section 4 manuals.
   Historically, this section was used in place of
   .Em EXIT STATUS
   for manuals in sections 1, 6, and 8; however, this practise is
   discouraged.
   .Pp
   See
   .Sx \&Bl
   .Fl diag .
   .
   .It Em ERRORS
   Documents error handling in sections 2, 3, and 9.
   .Pp
   See
   .Sx \&Er .
   .
   .It Em SEE ALSO
   References other manuals with related topics.  This section should exist
   for most manuals.  Cross-references should conventionally be ordered
   first by section, then alphabetically.
   .Pp
   See
   .Sx \&Xr .
   .
   .It Em STANDARDS
   References any standards implemented or used.  If not adhering to any
   standards, the
   .Em HISTORY
   section should be used instead.
   .Pp
   See
   .Sx \&St .
   .
   .It Em HISTORY
   The history of any manual without a
   .Em STANDARDS
   section should be described in this section.
   .
   .It Em AUTHORS
   Credits to authors, if applicable, should appear in this section.
   Authors should generally be noted by both name and an e-mail address.
   .Pp
   See
   .Sx \&An .
   .
   .It Em CAVEATS
   Explanations of common misuses and misunderstandings should be explained
   in this section.
   .
   .It Em BUGS
   Extant bugs should be described in this section.
   .
   .It Em SECURITY CONSIDERATIONS
   Documents any security precautions that operators should consider.
   .
 .El  .El
 .\" SUB-SECTION  .
   .
   .Sh MACRO SYNTAX
   Macros are one to three three characters in length and begin with a
   control character ,
   .Sq \&. ,
   at the beginning of the line.  An arbitrary amount of whitespace may
   sit between the control character and the macro name.  Thus, the
   following are equivalent:
   .Bd -literal -offset indent
   \&.Pp
   \&.\ \ \ \&Pp
   .Ed
   .
   .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  .Ss Block full-explicit
 None of these macros are callable or parsed.  The last column indicates  Multi-line scope closed by an explicit closing macro.  All macros
 the explicit scope rules.  All contains bodies, some may contain heads  contains bodies; only
 .Pq So \&Bf Sc .  .Sx \&Bf
   contains a head.
   .Bd -literal -offset indent
   \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
   \(lBbody...\(rB
   \&.Yc
   .Ed
   .
 .Pp  .Pp
 .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsableX" "closed by XXX"  .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsableX" "closed by XXX"
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope
 .It \&.Bd    Ta    \&No    Ta    \&No    Ta    closed by \&.Ed  .It Sx \&Bd  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ed
 .It \&.Ed    Ta    \&No    Ta    \&No    Ta    opened by \&.Bd  .It Sx \&Bf  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ef
 .It \&.Bl    Ta    \&No    Ta    \&No    Ta    closed by \&.El  .It Sx \&Bk  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Ek
 .It \&.El    Ta    \&No    Ta    \&No    Ta    opened by \&.Bl  .It Sx \&Bl  Ta    \&No     Ta    \&No     Ta    closed by Sx \&El
 .It \&.Bf    Ta    \&No    Ta    \&No    Ta    closed by \&.Ef  .It Sx \&Ed  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bd
 .It \&.Ef    Ta    \&No    Ta    \&No    Ta    opened by \&.Bf  .It Sx \&Ef  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bf
 .It \&.Bk    Ta    \&No    Ta    \&No    Ta    closed by \&.Ek  .It Sx \&Ek  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bk
 .It \&.Ek    Ta    \&No    Ta    \&No    Ta    opened by \&.Bk  .It Sx \&El  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Bl
 .El  .El
 .\" SUB-SECTION  .
 .Ss Block partial-implicit  .
 All of these are callable and parsed for further macros.  Their scopes  .Ss Block full-implicit
 close at the invocation's end-of-line.  Multi-line scope closed by end-of-file or implicitly by another macro.
   All macros have bodies; some
   .Po
   .Sx \&It Fl bullet ,
   .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  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" -compact -offset indent  .Bl -column -compact -offset indent "MacroX" "CallableX" "ParsableX" "closed by XXXXXXXXXXX"
 .It Em Macro Ta Em Callable Ta Em Parsable  .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope
 .It \&.Aq    Ta    Yes   Ta    Yes  .It Sx \&It  Ta    \&No     Ta    Yes      Ta    closed by Sx \&It , Sx \&El
 .It \&.Op    Ta    Yes   Ta    Yes  .It Sx \&Nd  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Sh
 .It \&.Bq    Ta    Yes   Ta    Yes  .It Sx \&Sh  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Sh
 .It \&.Dq    Ta    Yes   Ta    Yes  .It Sx \&Ss  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Sh , Sx \&Ss
 .It \&.Pq    Ta    Yes   Ta    Yes  
 .It \&.Qq    Ta    Yes   Ta    Yes  
 .It \&.Sq    Ta    Yes   Ta    Yes  
 .It \&.Brq   Ta    Yes   Ta    Yes  
 .It \&.D1    Ta    \&No  Ta    \&Yes  
 .It \&.Dl    Ta    \&No  Ta    Yes  
 .It \&.Ql    Ta    Yes   Ta    Yes  
 .El  .El
 .\" PARAGRAPH  .
 .Pp  .
 The  .Ss Block partial-explicit
 .Sq \&.Op  Like block full-explicit, but also with single-line scope.  Each
 may be broken by  has at least a body and, in limited circumstances, a head
 .Sq \&.Oc  .Po
 as in the following example:  .Sx \&Fo ,
   .Sx \&Eo
   .Pc
   and/or tail
   .Pq Sx \&Ec .
 .Bd -literal -offset indent  .Bd -literal -offset indent
 \&.Oo  \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
 \&.Op Fl a Oc  \(lBbody...\(rB
   \&.Yc \(lBtail...\(rB
   
   \&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB \
   \(lBbody...\(rB \&Yc \(lBtail...\(rB
 .Ed  .Ed
   .
 .Pp  .Pp
 In the above example, the scope of  
 .Sq \&.Op  
 is technically broken by  
 .Sq \&.Oc ,  
 however, due to the overwhelming existence of this sequence, it's  
 allowed.  
 .\" SUB-SECTION  
 .Ss Block partial-explicit  
 Each of these contains at least a body and, in limited circumstances, a  
 head  
 .Pq So \&.Fo Sc , So \&.Eo Sc  
 and/or tail  
 .Pq So \&.Ec Sc .  
 .Pp  
 .Bl -column "MacroX" "CallableX" "ParsableX" "closed by XXXX" -compact -offset indent  .Bl -column "MacroX" "CallableX" "ParsableX" "closed by XXXX" -compact -offset indent
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope  .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Scope
 .It \&.Ao    Ta    Yes   Ta    Yes    Ta    closed by \&.Ac  .It Sx \&Ac  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Ao
 .It \&.Ac    Ta    Yes   Ta    Yes    Ta    opened by \&.Ao  .It Sx \&Ao  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Ac
 .It \&.Bc    Ta    Yes   Ta    Yes    Ta    closed by \&.Bo  .It Sx \&Bc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Bo
 .It \&.Bo    Ta    Yes   Ta    Yes    Ta    opened by \&.Bc  .It Sx \&Bo  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Bc
 .It \&.Pc    Ta    Yes   Ta    Yes    Ta    closed by \&.Po  .It Sx \&Brc Ta    Yes      Ta    Yes      Ta    opened by Sx \&Bro
 .It \&.Po    Ta    Yes   Ta    Yes    Ta    opened by \&.Pc  .It Sx \&Bro Ta    Yes      Ta    Yes      Ta    closed by Sx \&Brc
 .It \&.Do    Ta    Yes   Ta    Yes    Ta    closed by \&.Dc  .It Sx \&Dc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Do
 .It \&.Dc    Ta    Yes   Ta    Yes    Ta    opened by \&.Do  .It Sx \&Do  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Dc
 .It \&.Xo    Ta    Yes   Ta    Yes    Ta    closed by \&.Xc  .It Sx \&Ec  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Eo
 .It \&.Xc    Ta    Yes   Ta    Yes    Ta    opened by \&.Xo  .It Sx \&Eo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Ec
 .It \&.Bro   Ta    Yes   Ta    Yes    Ta    closed by \&.Brc  .It Sx \&Fc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Fo
 .It \&.Brc   Ta    Yes   Ta    Yes    Ta    opened by \&.Bro  .It Sx \&Fo  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Fc
 .It \&.Oc    Ta    Yes   Ta    Yes    Ta    closed by \&.Oo  .It Sx \&Oc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Oo
 .It \&.Oo    Ta    Yes   Ta    Yes    Ta    opened by \&.Oc  .It Sx \&Oo  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Oc
 .It \&.So    Ta    Yes   Ta    Yes    Ta    closed by \&.Sc  .It Sx \&Pc  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Po
 .It \&.Sc    Ta    Yes   Ta    Yes    Ta    opened by \&.So  .It Sx \&Po  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Pc
 .It \&.Fc    Ta    Yes   Ta    Yes    Ta    opened by \&.Fo  .It Sx \&Qc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Oo
 .It \&.Fo    Ta    \&No  Ta    \&No   Ta    closed by \&.Fc  .It Sx \&Qo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Oc
 .It \&.Ec    Ta    Yes   Ta    Yes    Ta    opened by \&.Eo  .It Sx \&Re  Ta    \&No     Ta    \&No     Ta    opened by Sx \&Rs
 .It \&.Eo    Ta    Yes   Ta    Yes    Ta    closed by \&.Ec  .It Sx \&Rs  Ta    \&No     Ta    \&No     Ta    closed by Sx \&Re
 .It \&.Qc    Ta    Yes   Ta    Yes    Ta    opened by \&.Oo  .It Sx \&Sc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&So
 .It \&.Qo    Ta    Yes   Ta    Yes    Ta    closed by \&.Oc  .It Sx \&So  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Sc
 .It \&.Re    Ta    \&No  Ta    \&No   Ta    opened by \&.Rs  .It Sx \&Xc  Ta    Yes      Ta    Yes      Ta    opened by Sx \&Xo
 .It \&.Rs    Ta    \&No  Ta    \&No   Ta    closed by \&.Re  .It Sx \&Xo  Ta    Yes      Ta    Yes      Ta    closed by Sx \&Xc
 .El  .El
 .\" SUB-SECTION  .
 .Ss In-line  .
 In-line macros have only text children.  If a number (or inequality) of  .Ss Block partial-implicit
   Like block full-implicit, but with single-line scope closed by
   .Sx Reserved Characters
   or end of line.
   .Bd -literal -offset indent
   \&.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
   .Pp
   Note that the
   .Sx \&Vt
   macro is a
   .Sx Block partial-implicit
   only when invoked as the first macro
   in a SYNOPSIS section line, else it is
   .Sx In-line .
   .
   .
   .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  arguments is
 .Pq n ,  .Pq n ,
 then the macro accepts an arbitrary number of arguments.  then the macro accepts an arbitrary number of arguments.
   .Bd -literal -offset indent
   \&.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  .Pp
 .Bl -column "MacroX" "CallableX" "ParsableX" "Arguments" -compact -offset indent  .Bl -column "MacroX" "CallableX" "ParsableX" "Arguments" -compact -offset indent
 .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Arguments  .It Em Macro Ta Em Callable Ta Em Parsable Ta Em Arguments
 .It \&.Dd    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&%A  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Dt    Ta    \&No  Ta    \&No    Ta    n  .It Sx \&%B  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Os    Ta    \&No  Ta    \&No    Ta    n  .It Sx \&%C  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Pp    Ta    \&No  Ta    \&No    Ta    0  .It Sx \&%D  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Ad    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&%I  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.An    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&%J  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Ar    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&%N  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Cd    Ta    Yes   Ta    \&No    Ta    >0  .It Sx \&%O  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Cm    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&%P  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Dv    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&%Q  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Er    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&%R  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Ev    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&%T  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Ex    Ta    \&No  Ta    \&No    Ta    0  .It Sx \&%U  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Fa    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&%V  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Fd    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Ad  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Fl    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&An  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Fn    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&Ap  Ta    Yes      Ta    Yes      Ta    0
 .It \&.Ft    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Ar  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Ic    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&At  Ta    Yes      Ta    Yes      Ta    1
 .It \&.In    Ta    \&No  Ta    \&No    Ta    n  .It Sx \&Bsx Ta    Yes      Ta    Yes      Ta    n
 .It \&.Li    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Bt  Ta    \&No     Ta    \&No     Ta    0
 .It \&.Nm    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Bx  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Ot    Ta    \&No  Ta    \&No    Ta    n  .It Sx \&Cd  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.Pa    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Cm  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Rv    Ta    \&No  Ta    \&No    Ta    0  .It Sx \&Db  Ta    \&No     Ta    \&No     Ta    1
 .It \&.St    Ta    \&No  Ta    Yes     Ta    1  .It Sx \&Dd  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.Va    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Dt  Ta    \&No     Ta    \&No     Ta    n
 .It \&.Vt    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&Dv  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Xr    Ta    Yes   Ta    Yes     Ta    >0, <3  .It Sx \&Dx  Ta    Yes      Ta    Yes      Ta    n
 .It \&.%A    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Em  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.%B    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&En  Ta    \&No     Ta    \&No     Ta    0
 .It \&.%C    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Er  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.%D    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Es  Ta    \&No     Ta    \&No     Ta    0
 .It \&.%I    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Ev  Ta    Yes      Ta    Yes      Ta    n
 .It \&.%J    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Ex  Ta    \&No     Ta    \&No     Ta    n
 .It \&.%N    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Fa  Ta    Yes      Ta    Yes      Ta    n
 .It \&.%O    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Fd  Ta    \&No     Ta    \&No     Ta    >0
 .It \&.%P    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Fl  Ta    Yes      Ta    Yes      Ta    n
 .It \&.%R    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Fn  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.%T    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Fr  Ta    \&No     Ta    \&No     Ta    n
 .It \&.%V    Ta    \&No  Ta    \&No    Ta    >0  .It Sx \&Ft  Ta    Yes      Ta    Yes      Ta    n
 .It \&.At    Ta    Yes   Ta    Yes     Ta    1  .It Sx \&Fx  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Bsx   Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Hf  Ta    \&No     Ta    \&No     Ta    n
 .It \&.Bx    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Ic  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.Db    Ta    \&No  Ta    \&No    Ta    1  .It Sx \&In  Ta    \&No     Ta    \&No     Ta    n
 .It \&.Em    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&Lb  Ta    \&No     Ta    \&No     Ta    1
 .It \&.Fx    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Li  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Ms    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&Lk  Ta    Yes      Ta    Yes      Ta    n
 .It \&.No    Ta    Yes   Ta    Yes     Ta    0  .It Sx \&Lp  Ta    \&No     Ta    \&No     Ta    0
 .It \&.Ns    Ta    Yes   Ta    Yes     Ta    0  .It Sx \&Ms  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.Nx    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Mt  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.Ox    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Nm  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Pf    Ta    \&No  Ta    Yes     Ta    1  .It Sx \&No  Ta    Yes      Ta    Yes      Ta    0
 .It \&.Sm    Ta    \&No  Ta    \&No    Ta    1  .It Sx \&Ns  Ta    Yes      Ta    Yes      Ta    0
 .It \&.Sx    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&Nx  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Sy    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&Os  Ta    \&No     Ta    \&No     Ta    n
 .It \&.Tn    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&Ot  Ta    \&No     Ta    \&No     Ta    n
 .It \&.Ux    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Ox  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Dx    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Pa  Ta    Yes      Ta    Yes      Ta    n
 .It \&.Bt    Ta    \&No  Ta    \&No    Ta    0  .It Sx \&Pf  Ta    Yes      Ta    Yes      Ta    1
 .It \&.Hf    Ta    \&No  Ta    \&No    Ta    n  .It Sx \&Pp  Ta    \&No     Ta    \&No     Ta    0
 .It \&.Fr    Ta    \&No  Ta    \&No    Ta    n  .It Sx \&Rv  Ta    \&No     Ta    \&No     Ta    n
 .It \&.Ud    Ta    \&No  Ta    \&No    Ta    0  .It Sx \&Sm  Ta    \&No     Ta    \&No     Ta    1
 .It \&.Lb    Ta    \&No  Ta    \&No    Ta    1  .It Sx \&St  Ta    \&No     Ta    Yes      Ta    1
 .It \&.Ap    Ta    Yes   Ta    Yes     Ta    0  .It Sx \&Sx  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.Lp    Ta    \&No  Ta    \&No    Ta    0  .It Sx \&Sy  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.Lk    Ta    Yes   Ta    Yes     Ta    n  .It Sx \&Tn  Ta    Yes      Ta    Yes      Ta    >0
 .It \&.Mt    Ta    Yes   Ta    Yes     Ta    >0  .It Sx \&Ud  Ta    \&No     Ta    \&No     Ta    0
 .It \&.Es    Ta    \&No  Ta    \&No    Ta    0  .It Sx \&Ux  Ta    Yes      Ta    Yes      Ta    n
 .It \&.En    Ta    \&No  Ta    \&No    Ta    0  .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
   .
   .
   .Sh REFERENCE
   This section is a canonical reference of all macros, arranged
   alphabetically.  For the scoping of individual macros, see
   .Sx MACRO SYNTAX .
   .
   .Ss \&%A
   Author name of an
   .Sx \&Rs
   block.  Multiple authors should each be accorded their own
   .Sx \%%A
   line.  Author names should be ordered with full or abbreviated
   forename(s) first, then full surname.
   .
   .Ss \&%B
   Book title of an
   .Sx \&Rs
   block.  This macro may also be used in a non-bibliographic context when
   referring to book titles.
   .
   .Ss \&%C
   Publication city or location of an
   .Sx \&Rs
   block.
 .Pp  .Pp
   .Em Remarks :
   this macro is not implemented in
   .Xr groff 1 .
   .
   .Ss \&%D
   Publication date of an
   .Sx \&Rs
   block.  This should follow the reduced or canonical form syntax
   described in
   .Sx Dates .
   .
   .Ss \&%I
   Publisher or issuer name of an
   .Sx \&Rs
   block.
   .
   .Ss \&%J
   Journal name of an
   .Sx \&Rs
   block.
   .
   .Ss \&%N
   Issue number (usually for journals) of an
   .Sx \&Rs
   block.
   .
   .Ss \&%O
   Optional information of an
   .Sx \&Rs
   block.
   .
   .Ss \&%P
   Book or journal page number of an
   .Sx \&Rs
   block.
   .
   .Ss \&%Q
   Institutional author (school, government, etc.) of an
   .Sx \&Rs
   block.  Multiple institutional authors should each be accorded their own
   .Sx \&%Q
   line.
   .
   .Ss \&%R
   Technical report name of an
   .Sx \&Rs
   block.
   .
   .Ss \&%T
   Article title of an
   .Sx \&Rs
   block.  This macro may also be used in a non-bibliographical context
   when referring to article titles.
   .
   .Ss \&%U
   URI of reference document.
   .
   .Ss \&%V
   Volume number of an
   .Sx \&Rs
   block.
   .
   .Ss \&Ac
   Closes an
   .Sx \&Ao
   block.  Does not have any tail arguments.
   .
   .Ss \&Ad
   Address construct: usually in the context of an computational address in
   memory, not a physical (post) address.
   .Pp
   Examples:
   .D1 \&.Ad [0,$]
   .D1 \&.Ad 0x00000000
   .
   .Ss \&An
   Author name.  This macro may alternatively accepts the following
   arguments, although these may not be specified along with a parameter:
   .Bl -tag -width 12n -offset indent
   .It Fl split
   Renders a line break before each author listing.
   .It Fl nosplit
   The opposite of
   .Fl split .
   .El
   .Pp
   In the AUTHORS section, the default is not to split the first author
   listing, but all subsequent author listings, whether or not they're
   interspersed by other macros or text, are split.  Thus, specifying
   .Fl split
   will cause the first listing also to be split.  If not in the AUTHORS
   section, the default is not to split.
   .Pp
   Examples:
   .D1 \&.An -nosplit
   .D1 \&.An J. D. Ullman .
   .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:
   .D1 \&.Fl -key= \&Ns \&Ao \&Ar val \&Ac
   .Pp
   See also
   .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
   \&.Fn execve Ap d
   .Ed
   .
   .Ss \&Aq
   Encloses its arguments in angled brackets.
   .Pp
   Examples:
   .D1 \&.Fl -key= \&Ns \&Aq \&Ar val
   .Pp
   .Em Remarks :
   this macro is often abused for rendering URIs, which should instead use
   .Sx \&Lk
   or
   .Sx \&Mt ,
   or to note pre-processor
   .Dq Li #include
   statements, which should use
   .Sx \&In .
   .Pp
   See also
   .Sx \&Ao .
   .
   .Ss \&Ar
   Command arguments.  If an argument is not provided, the string
   .Dq file ...
   is used as a default.
   .Pp
   Examples:
   .D1 \&.Fl o \&Ns \&Ar file1
   .D1 \&.Ar
   .D1 \&.Ar arg1 , arg2 .
   .
   .Ss \&At
   Formats an AT&T version.  Accepts at most one parameter:
   .Bl -tag -width 12n -offset indent
   .It Cm v[1-7] | 32v
   A version of
   .At .
   .It Cm V[.[1-4]]?
   A system version of
   .At .
   .El
   .Pp
   Note that these parameters do not begin with a hyphen.
   .Pp
   Examples:
   .D1 \&.At
   .D1 \&.At V.1
   .Pp
   See also
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .
   .Ss \&Bc
   Closes a
   .Sx \&Bo
   block.  Does not have any tail arguments.
   .
   .Ss \&Bd
   Begins a display block.  A display is collection of macros or text which
   may be collectively offset or justified in a manner different from that
   of the enclosing context.  By default, the block is preceded by a
   vertical space.
   .Pp
   Each display is associated with a type, which must be one of the
   following arguments:
   .Bl -tag -width 12n -offset indent
   .It Fl ragged
   Only left-justify the block.
   .It Fl unfilled
   Do not justify the block at all.
   .It Fl filled
   Left- and right-justify the block.
   .It Fl literal
   Alias for
   .Fl unfilled .
   .It Fl centered
   Centre-justify each line.
   .El
   .Pp
   The type must be provided first.  Secondary arguments are as follows:
   .Bl -tag -width 12n -offset indent
   .It Fl offset Ar width
   Offset by the value of
   .Ar width ,
   which is interpreted as one of the following, specified in order:
   .Bl -item
   .It
   As one of the pre-defined strings
   .Ar indent ,
   the width of standard indentation;
   .Ar indent-two ,
   twice
   .Ar indent ;
   .Ar left ,
   which has no effect ;
   .Ar right ,
   which justifies to the right margin; and
   .Ar center ,
   which aligns around an imagined centre axis.
   .It
   As a precalculated width for a named macro.  The most popular is the
   imaginary macro
   .Ar \&Ds ,
   which resolves to
   .Ar 6n .
   .It
   As a scaling unit following the syntax described in
   .Sx Scaling Widths .
   .It
   As the calculated string length of the opaque string.
   .El
   .Pp
   If unset, it will revert to the value of
   .Ar 8n
   as described in
   .Sx Scaling Widths .
   .It Fl compact
   Do not assert a vertical space before the block.
   .It Fl file Ar file
   Prepend the file
   .Ar file
   before any text or macros within the block.
   .El
   .Pp
   Examples:
   .Bd -literal -offset indent
   \&.Bd \-unfilled \-offset two-indent \-compact
      Hello       world.
   \&.Ed
   .Ed
   .Pp
   See also
   .Sx \&D1
   and
   .Sx \&Dl .
   .
   .Ss \&Bf
   .Ss \&Bk
   .Ss \&Bl
   .\" Begins a list composed of one or more list entries.  A list entry is
   .\" specified by the
   .\" .Sx \&It
   .\" macro, which consists of a head and optional body.  By default, a list
   .\" is preceded by a blank line.  A list must specify one of the following
   .\" list types:
   .\" .Bl -tag -width 12n
   .\" .It Fl bullet
   .\" A list offset by a bullet.  The head of list entries must be empty.
   .\" List entry bodies are justified after the bullet.
   .\" .It Fl column
   .\" A columnated list.  The number of columns is specified as arguments to
   .\" the
   .\" .Sx \&Bl
   .\" macro (the deprecated form of following the invocation of
   .\" .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
   Examples:
   .Bd -literal -offset indent
   \&.Bo 1 ,
   \&.Dv BUFSIZ \&Bc
   .Ed
   .Pp
   See also
   .Sx \&Bq .
   .
   .Ss \&Bq
   Encloses its arguments in square brackets.
   .Pp
   Examples:
   .D1 \&.Bq 1 , \&Dv BUFSIZ
   .Pp
   .Em Remarks :
   this macro is sometimes abused to emulate optional arguments for
   commands; the correct macros to use for this purpose are
   .Sx \&Op ,
   .Sx \&Oo ,
   and
   .Sx \&Oc .
   .Pp
   See also
   .Sx \&Bo .
   .
   .Ss \&Brc
   Closes a
   .Sx \&Bro
   block.  Does not have any tail arguments.
   .
   .Ss \&Bro
   Begins a block enclosed by curly braces.  Does not have any head
   arguments.
   .Pp
   Examples:
   .Bd -literal -offset indent
   \&.Bro 1 , ... ,
   \&.Va n \&Brc
   .Ed
   .Pp
   See also
   .Sx \&Brq .
   .
   .Ss \&Brq
   Encloses its arguments in curly braces.
   .Pp
   Examples:
   .D1 \&.Brq 1 , ... , \&Va n
   .Pp
   See also
   .Sx \&Bro .
   .
   .Ss \&Bsx
   Format the BSD/OS version provided as an argument, or a default value if
   no argument is provided.
   .Pp
   Examples:
   .D1 \&.Bsx 1.0
   .D1 \&.Bsx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .
   .Ss \&Bt
   Prints
   .Dq is currently in beta test.
   .
   .Ss \&Bx
   Format the BSD version provided as an argument, or a default value if no
   argument is provided.
   .Pp
   Examples:
   .D1 \&.Bx 4.4
   .D1 \&.Bx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .
   .Ss \&Cd
   Configuration declaration.  This denotes strings accepted by
   .Xr config 8 .
   .Pp
   Examples:
   .D1 \&.Cd device le0 at scode?
   .Pp
   .Em Remarks :
   this macro is commonly abused by using quoted literals to retain
   white-space and align consecutive
   .Sx \&Cd
   declarations.  This practise is discouraged.
   .
   .Ss \&Cm
   Command modifiers.  Useful when specifying configuration options or
   keys.
   .Pp
   Examples:
   .D1 \&.Cm ControlPath
   .D1 \&.Cm ControlMaster
   .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:
   .D1 \&.D1 \&Fl abcdefgh
   .Pp
   See also
   .Sx \&Bd
   and
   .Sx \&Dl .
   .
   .Ss \&Db
   .Ss \&Dc
   Closes a
   .Sx \&Do
   block.  Does not have any tail arguments.
   .
   .Ss \&Dd
   Document date.  This is the mandatory first macro of any
   .Nm
   manual.  Its calling syntax is as follows:
   .Pp
   .D1 \. Ns Sx \&Dd Cm date
   .Pp
 The  The
 .Sq \&.Ot ,  .Cm date
 .Sq \&.Fr ,  field may be either
 .Sq \&.Es  .Ar $\&Mdocdate$ ,
   which signifies the current manual revision date dictated by
   .Xr cvs 1 ,
   or instead a valid canonical date as specified by
   .Sx Dates .
   If a date does not conform, the current date is used instead.
   .Pp
   Examples:
   .D1 \&.Dd $\&Mdocdate$
   .D1 \&.Dd $\&Mdocdate: July 21 2007$
   .D1 \&.Dd July 21, 2007
   .Pp
   See also
   .Sx \&Dt
 and  and
 .Sq \&.En ,  .Sx \&Os .
 macros are obsolete.  .
 .\" SECTION  .Ss \&Dl
 .Sh COMPATIBILITY  One-line intended display.  This is formatted as literal text and is
 This section documents compatibility with other roff implementations, at  useful for commands and invocations.  It is followed by a newline.
 this time limited to  .Pp
   Examples:
   .D1 \&.Dl % mandoc mdoc.7 | less
   .Pp
   See also
   .Sx \&Bd
   and
   .Sx \&D1 .
   .
   .Ss \&Do
   Begins a block enclosed by double quotes.  Does not have any head
   arguments.
   .Pp
   Examples:
   .D1 \&.D1 \&Do April is the cruellest month \&Dc \e(em T.S. Eliot
   .Pp
   See also
   .Sx \&Dq .
   .
   .Ss \&Dq
   Encloses its arguments in double quotes.
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Dq April is the cruellest month
   \e(em T.S. Eliot
   .Ed
   .Pp
   See also
   .Sx \&Do .
   .
   .Ss \&Dt
   Document title.  This is the mandatory second macro of any
   .Nm
   file.  Its calling syntax is as follows:
   .Pp
   .D1 \. Ns Sx \&Dt Cm title section Op Cm volume | arch
   .Pp
   Its arguments are as follows:
   .Bl -tag -width Ds -offset Ds
   .It Cm title
   The document's title (name).  This should be capitalised and is
   required.
   .It Cm section
   The manual section.  This may be one of
   .Ar 1
   .Pq utilities ,
   .Ar 2
   .Pq system calls ,
   .Ar 3
   .Pq libraries ,
   .Ar 3p
   .Pq Perl libraries ,
   .Ar 4
   .Pq devices ,
   .Ar 5
   .Pq file formats ,
   .Ar 6
   .Pq games ,
   .Ar 7
   .Pq miscellaneous ,
   .Ar 8
   .Pq system utilities ,
   .Ar 9
   .Pq kernel functions ,
   .Ar X11
   .Pq X Window System ,
   .Ar X11R6
   .Pq X Window System ,
   .Ar unass
   .Pq unassociated ,
   .Ar local
   .Pq local system ,
   .Ar draft
   .Pq draft manual ,
   or
   .Ar paper
   .Pq paper .
   It is also required and should correspond to the manual's filename
   suffix.
   .It Cm volume
   This overrides the volume inferred from
   .Ar section .
   This field is optional, and if specified, must be one of
   .Ar USD
   .Pq users' supplementary documents ,
   .Ar PS1
   .Pq programmers' supplementary documents ,
   .Ar AMD
   .Pq administrators' supplementary documents ,
   .Ar SMM
   .Pq system managers' manuals ,
   .Ar URM
   .Pq users' reference manuals ,
   .Ar PRM
   .Pq programmers' reference manuals ,
   .Ar KM
   .Pq kernel manuals ,
   .Ar IND
   .Pq master index ,
   .Ar MMI
   .Pq master index ,
   .Ar LOCAL
   .Pq local manuals ,
   .Ar LOC
   .Pq local manuals ,
   or
   .Ar CON
   .Pq contributed manuals .
   .It 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
   .Pp
   Examples:
   .D1 \&.Dt FOO 1
   .D1 \&.Dt FOO 4 KM
   .D1 \&.Dt FOO 9 i386
   .D1 \&.Dt FOO 9 KM i386
   .Pp
   See also
   .Sx \&Dd
   and
   .Sx \&Os .
   .
   .Ss \&Dv
   Defined variables such as preprocessor constants.
   .Pp
   Examples:
   .D1 \&.Dv BUFSIZ
   .D1 \&.Dv STDOUT_FILENO
   .Pp
   See also
   .Sx \&Er .
   .
   .Ss \&Dx
   Format the DragonFly BSD version provided as an argument, or a default
   value if no argument is provided.
   .Pp
   Examples:
   .D1 \&.Dx 2.4.1
   .D1 \&.Dx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .
   .Ss \&Ec
   .Ss \&Ed
   .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
   Examples:
   .D1 \&.Em Warnings!
   .D1 \&.Em Remarks :
   .
   .Ss \&En
   .Ss \&Eo
   .Ss \&Er
   Display error constants.
   .Pp
   Examples:
   .D1 \&.Er EPERM
   .D1 \&.Er ENOENT
   .Pp
   See also
   .Sx \&Dv .
   .
   .Ss \&Es
   .
   .Ss \&Ev
   Environmental variables such as those specified in
   .Xr environ 7 .
   .Pp
   Examples:
   .D1 \&.Ev DISPLAY
   .D1 \&.Ev PATH
   .
   .Ss \&Ex
   Inserts text regarding a utility's exit values.  This macro must have
   first the
   .Fl std
   argument specified, then an optional
   .Ar utility .
   If
   .Ar utility
   is not provided, the document's name as stipulated in
   .Sx \&Nm
   is provided.
   .Ss \&Fa
   .Ss \&Fc
   .Ss \&Fd
   .Ss \&Fl
   Command-line flag.  Used when listing arguments to command-line
   utilities.  Prints a fixed-width hyphen
   .Sq \-
   directly followed by each argument.  If no arguments are provided, a hyphen is
   printed followed by a space.  If the argument is a macro, a hyphen is
   prefixed to the subsequent macro output.
   .Pp
   Examples:
   .D1 \&.Fl a b c
   .D1 \&.Fl \&Pf a b
   .D1 \&.Fl
   .D1 \&.Op \&Fl o \&Ns \&Ar file
   .Pp
   See also
   .Sx \&Cm .
   .
   .Ss \&Fn
   .Ss \&Fo
   .Ss \&Fr
   .Ss \&Ft
   .Ss \&Fx
   Format the FreeBSD version provided as an argument, or a default value
   if no argument is provided.
   .Pp
   Examples:
   .D1 \&.Fx 7.1
   .D1 \&.Fx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Nx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .
   .Ss \&Hf
   .Ss \&Ic
   .Ss \&In
   .Ss \&It
   .Ss \&Lb
   .Ss \&Li
   .Ss \&Lk
   Format a hyperlink.  The calling syntax is as follows:
   .Pp
   .D1 \. Ns Sx \&Lk Cm uri Op Cm name
   .Pp
   Examples:
   .D1 \&.Lk http://bsd.lv "The BSD.lv Project"
   .D1 \&.Lk http://bsd.lv
   .Pp
   See also
   .Sx \&Mt .
   .
   .Ss \&Lp
   .Ss \&Ms
   .Ss \&Mt
   .Ss \&Nd
   .Ss \&Nm
   .Ss \&No
   .Ss \&Ns
   .Ss \&Nx
   Format the NetBSD version provided as an argument, or a default value if
   no argument is provided.
   .Pp
   Examples:
   .D1 \&.Nx 5.01
   .D1 \&.Nx
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Ox ,
   and
   .Sx \&Ux .
   .
   .Ss \&Oc
   .Ss \&Oo
   .Ss \&Op
   .Ss \&Os
   Document operating system version.  This is the mandatory third macro of
   any
   .Nm
   file.  Its calling syntax is as follows:
   .Pp
   .D1 \. Ns Sx \&Os Op Cm system
   .Pp
   The optional
   .Cm system
   parameter specifies the relevant operating system or environment.  Left
   unspecified, it defaults to the local operating system version.  This is
   the suggested form.
   .Pp
   Examples:
   .D1 \&.Os
   .D1 \&.Os KTH/CSC/TCS
   .D1 \&.Os BSD 4.3
   .Pp
   See also
   .Sx \&Dd
   and
   .Sx \&Dt .
   .
   .Ss \&Ot
   Unknown usage.
   .Pp
   .Em Remarks :
   this macro has been deprecated.
   .
   .Ss \&Ox
   Format the OpenBSD version provided as an argument, or a default value
   if no argument is provided.
   .Pp
   Examples:
   .D1 \&.Ox 4.5
   .D1 \&.Ox
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   and
   .Sx \&Ux .
   .
   .Ss \&Pa
   .Ss \&Pc
   .Ss \&Pf
   .Ss \&Po
   .Ss \&Pp
   .Ss \&Pq
   .Ss \&Qc
   .Ss \&Ql
   .Ss \&Qo
   .Ss \&Qq
   .
   .Ss \&Re
   Closes a
   .Sx \&Rs
   block.  Does not have any tail arguments.
   .
   .Ss \&Rs
   Begins a bibliographic
   .Pq Dq reference
   block.  Does not have any head arguments.  The block macro may only
   contain
   .Sx \&%A ,
   .Sx \&%B ,
   .Sx \&%C ,
   .Sx \&%D ,
   .Sx \&%I ,
   .Sx \&%J ,
   .Sx \&%N ,
   .Sx \&%O ,
   .Sx \&%P ,
   .Sx \&%Q ,
   .Sx \&%R ,
   .Sx \&%T ,
   and
   .Sx \&%V
   child macros (at least one must be specified).
   .Pp
   Examples:
   .Bd -literal -offset indent -compact
   \&.Rs
   \&.%A J. E. Hopcroft
   \&.%A J. D. Ullman
   \&.%B Introduction to Automata Theory, Languages, and Computation
   \&.%I Addison-Wesley
   \&.%C Reading, Massachusettes
   \&.%D 1979
   \&.Re
   .Ed
   .Pp
   If an
   .Sx \&Rs
   block is used within a SEE ALSO section, a vertical space is asserted
   before the rendered output, else the block continues on the current
   line.
   .
   .Ss \&Rv
   .Ss \&Sc
   .Ss \&Sh
   .Ss \&Sm
   .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
   Examples:
   .D1 \&.Ux
   .Pp
   See also
   .Sx \&At ,
   .Sx \&Bsx ,
   .Sx \&Bx ,
   .Sx \&Dx ,
   .Sx \&Fx ,
   .Sx \&Nx ,
   and
   .Sx \&Ox .
   .
   .Ss \&Va
   .Ss \&Vt
   A variable type.  This is also used for indicating global variables in the
   SYNOPSIS section, in which case a variable name is also specified.  Note that
   it accepts
   .Sx Block partial-implicit
   syntax when invoked as the first macro in the SYNOPSIS section, else it
   accepts ordinary
   .Sx In-line
   syntax.
   .Pp
   Note that this should not be confused with
   .Sx \&Ft ,
   which is used for function return types.
   .Pp
   Examples:
   .D1 \&.Vt unsigned char
   .D1 \&.Vt extern const char * const sys_signame[] ;
   .Pp
   See also
   .Sx \&Ft
   and
   .Sx \&Va .
   .
   .Ss \&Xc
   Close a scope opened by
   .Sx \&Xo .
   .
   .Ss \&Xo
   Open an extension scope.  This macro originally existed to extend the
   9-argument limit of troff; since this limit has been lifted, the macro
   has been deprecated.
   .
   .Ss \&Xr
   Link to another manual
   .Pq Qq cross-reference .
   Its calling syntax is
   .Pp
   .D1 \. Ns Sx \&Xr Cm name section
   .Pp
   The
   .Cm name
   and
   .Cm section
   are the name and section of the linked manual.  If
   .Cm section
   is followed by non-punctuation, an
   .Sx \&Ns
   is inserted into the token stream.  This behaviour is for compatibility
   with
 .Xr groff 1 .  .Xr groff 1 .
 The term  .Pp
   Examples:
   .D1 \&.Xr mandoc 1
   .D1 \&.Xr mandoc 1 ;
   .D1 \&.Xr mandoc 1 \&Ns s behaviour
   .
   .Ss \&br
   .Ss \&sp
   .
   .
   .Sh COMPATIBILITY
   This section documents compatibility between mandoc and other other
   troff implementations, at this time limited to GNU troff
   .Pq Qq groff .
   The term
 .Qq historic groff  .Qq historic groff
 refers to those versions before the  refers to groff versions before the
 .Pa doc.tmac  .Pa doc.tmac
 file re-write  file re-write
 .Pq somewhere between 1.15 and 1.19 .  .Pq somewhere between 1.15 and 1.19 .
   .
 .Pp  .Pp
   Heirloom troff, the other significant troff implementation accepting
   \-mdoc, is similar to historic groff.
   .
   .Pp
 .Bl -dash -compact  .Bl -dash -compact
 .\" LIST-ITEM  
 .It  .It
 Some character sequences in groff are not handled depending on escape  The comment syntax
 style, e.g.,  .Sq \e."
 .Sq \e(ba  is no longer accepted.
   .
   .It
   In groff, the
   .Sx \&Pa
   macro does not format its arguments when used in the FILES section under
   certain list types.  mandoc does.
   .
   .It
   Historic groff does not print a dash for empty
   .Sx \&Fl
   arguments.  mandoc and newer groff implementations do.
   .It
   groff behaves irregularly when specifying
   .Sq \ef
   .Sx Text Decoration
   within line-macro scopes.  mandoc follows a consistent system.
   .
   .It
   In mandoc, negative scaling units are truncated to zero; groff would
   move to prior lines.  Furthermore, the
   .Sq f
   scaling unit, while accepted, is rendered as the default unit.
   .
   .It
   In quoted literals, groff allowed pair-wise double-quotes to produce a
   standalone double-quote in formatted output.  This idiosyncratic
   behaviour is not applicable in mandoc.
   .
   .It
   Display types
   .Sx \&Bd
   .Fl center
 and  and
 .Sq \e*(Ba  .Fl right
 may not be interchanged.  This is no longer the case: all character  are aliases for
 sequences resolve to the same symbol, regardless the escape style.  .Fl left
 .\" LIST-ITEM  in manodc.  Furthermore, the
   .Fl file Ar file
   argument is ignored.  Lastly, since text is not right-justified in
   mandoc (or even groff),
   .Fl ragged
   and
   .Fl filled
   are aliases, as are
   .Fl literal
   and
   .Fl unfilled .
   .
 .It  .It
 Blocks of whitespace are stripped from both macro and free-form text  In mandoc, blocks of whitespace are stripped from both macro and
 lines (except when in literal mode), while groff would retain whitespace  free-form text lines (except when in literal mode); groff would retain
 in free-form text lines.  whitespace in free-form text lines.
 .\" LIST-ITEM  .
 .It  .It
 Historic groff has many un-callable macros.  Most of these (excluding  Historic groff has many un-callable macros.  Most of these (excluding
 some block-level macros) are now callable, conforming to the  some block-level macros) are now callable.
 non-historic groff version.  .
 .\" LIST-ITEM  
 .It  .It
 The vertical bar  The vertical bar
 .Sq \(ba  .Sq \(ba
 made historic groff  made historic groff
 .Qq go orbital  .Qq go orbital
 but is a proper delimiter in this implementation.  but has been a proper delimiter since then.
 .\" LIST-ITEM  .
 .It  .It
 .Sq \&.It \-nested  .Sx \&It Fl nested
 is assumed for all lists (it wasn't in historic groff): any list may be  is assumed for all lists (it wasn't in historic groff): any list may be
 nested and  nested and
 .Sq \-enum  .Fl enum
 lists will restart the sequence only for the sub-list.  lists will restart the sequence only for the sub-list.
 .\" LIST-ITEM  .
 .It  .It
 .Sq \&.It \-column  
 syntax where column widths may be preceded by other arguments (instead  
 of proceeded) is not supported.  
 .\" LIST-ITEM  
 .It  
 The  
 .Sq \&.At  
 macro only accepts a single parameter.  
 .\" LIST-ITEM  
 .It  
 Some manuals use  Some manuals use
 .Sq \&.Li  .Sx \&Li
 incorrectly by following it with a reserved character and expecting the  incorrectly by following it with a reserved character and expecting the
 delimiter to render.  This is not supported.  delimiter to render.  This is not supported in mandoc.
 .\" LIST-ITEM  .
 .It  .It
 If an special-character control character is escaped  In groff, the
 .Sq \e\e ,  .Sx \&Fo
 it will obviously not render the subsequent sequence.  Even newer  macro only produces the first parameter.  This is not the case in
 versions of groff seem to dither on this.  mandoc.
 .\" LIST-ITEM  .
 .It  .It
 In groff, the  In groff, the
 .Sq \&.Fo  .Sx \&Cd ,
 macro only produces the first parameter.  This is no longer the case.  .Sx \&Er ,
   and
   .Sx \&Ex
   macros were stipulated only to occur in certain manual sections.  mandoc
   does not have these restrictions.
 .El  .El
 .\" SECTION  .
   .
 .Sh SEE ALSO  .Sh SEE ALSO
 .Xr mandoc 1 ,  .Xr mandoc 1 ,
 .Xr mandoc_char 7  .Xr mandoc_char 7
 .\" SECTION  .
   .
 .Sh AUTHORS  .Sh AUTHORS
 The  The
 .Nm  .Nm
 utility was written by  reference was written by
 .An Kristaps Dzonsons Aq kristaps@kth.se .  .An Kristaps Dzonsons Aq kristaps@kth.se .
 .\" SECTION  .\"
 .Sh CAVEATS  .\" XXX: this really isn't the place for these caveats.
 There are many ambiguous parts of mdoc.  .\" .
 .Pp  .\" .
 .Bl -dash -compact  .\" .Sh CAVEATS
 .\" LIST-ITEM  .\" There are many ambiguous parts of mdoc.
 .It  .\" .
 .Sq \&.Fa  .\" .Pp
 should be  .\" .Bl -dash -compact
 .Sq \&.Va  .\" .It
 as function arguments are variables.  .\" .Sq \&Fa
 .\" LIST-ITEM  .\" should be
 .It  .\" .Sq \&Va
 .Sq \&.Ft  .\" as function arguments are variables.
 should be  .\" .It
 .Sq \&.Vt  .\" .Sq \&Ft
 as function return types are still types.  Furthermore, the  .\" should be
 .Sq \&.Ft  .\" .Sq \&Vt
 should be removed and  .\" as function return types are still types.  Furthermore, the
 .Sq \&.Fo ,  .\" .Sq \&Ft
 which ostensibly follows it, should follow the same convention as  .\" should be removed and
 .Sq \&.Va .  .\" .Sq \&Fo ,
 .\" LIST-ITEM  .\" which ostensibly follows it, should follow the same convention as
 .It  .\" .Sq \&Va .
 .Sq \&.Va  .\" .It
 should formalise that only one or two arguments are acceptable: a  .\" .Sq \&Va
 variable name and optional, preceding type.  .\" should formalise that only one or two arguments are acceptable: a
 .\" LIST-ITEM  .\" variable name and optional, preceding type.
 .It  .\" .It
 .Sq \&.Fd  .\" .Sq \&Fd
 is ambiguous.  It's commonly used to indicate an include file in the  .\" is ambiguous.  It's commonly used to indicate an include file in the
 synopsis section.  .\" synopsis section.
 .Sq \&.In  .\" .Sq \&In
 should be used, instead.  .\" should be used, instead.
 .\" LIST-ITEM  .\" .It
 .It  .\" Only the
 Only the  .\" .Sq \-literal
 .Sq \-literal  .\" argument to
 argument to  .\" .Sq \&Bd
 .Sq \&.Bd  .\" makes sense.  The remaining ones should be removed.
 makes sense.  The remaining ones should be removed.  .\" .It
 .\" LIST-ITEM  .\" The
 .It  .\" .Sq \&Xo
 The  .\" and
 .Sq \&.Xo  .\" .Sq \&Xc
 and  .\" macros should be deprecated.
 .Sq \&.Xc  .\" .It
 macros should be deprecated.  .\" The
 .\" LIST-ITEM  .\" .Sq \&Dt
 .It  .\" macro lacks clarity.  It should be absolutely clear which title will
 The  .\" render when formatting the manual page.
 .Sq \&.Dt  .\" .It
 macro lacks clarity.  It should be absolutely clear which title will  .\" A
 render when formatting the manual page.  .\" .Sq \&Lx
 .\" LIST-ITEM  .\" should be provided for Linux (\(`a la
 .It  .\" .Sq \&Ox ,
 A  .\" .Sq \&Nx
 .Sq \&.Lx  .\" etc.).
 should be provided for Linux (\(`a la  .\" .It
 .Sq \&.Ox ,  .\" There's no way to refer to references in
 .Sq \&.Nx  .\" .Sq \&Rs/Re
 etc.).  .\" blocks.
 .\" LIST-ITEM  .\" .It
 .It  .\" The \-split and \-nosplit dictates via
 There's no way to refer to references in  .\" .Sq \&An
 .Sq \&.Rs/.Re  .\" are re-set when entering and leaving the AUTHORS section.
 blocks.  .\" .El
 .\" LIST-ITEM  .\" .
 .It  
 The \-split and \-nosplit arguments to  
 .Sq \&.An  
 are inane.  
 .El  
Legend:
Removed from v.1.42  
changed lines
  Added in v.1.93
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