-.\" $Id: mdoc.7,v 1.227 2014/02/16 14:26:55 schwarze Exp $
+.\" $Id: mdoc.7,v 1.262 2017/02/16 14:38:12 schwarze Exp $
.\"
.\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
-.\" Copyright (c) 2010, 2011, 2013 Ingo Schwarze <schwarze@openbsd.org>
+.\" Copyright (c) 2010, 2011, 2013-2017 Ingo Schwarze <schwarze@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
-.Dd $Mdocdate: February 16 2014 $
+.Dd $Mdocdate: February 16 2017 $
.Dt MDOC 7
.Os
.Sh NAME
The
\&.Nm
utility processes files ...
+\&.\e\(dq .Sh CONTEXT
+\&.\e\(dq For section 9 functions only.
\&.\e\(dq .Sh IMPLEMENTATION NOTES
\&.\e\(dq Not used in OpenBSD.
\&.\e\(dq .Sh RETURN VALUES
\&.El
.Ed
.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.
.Pp
Since the
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
References other manuals with related topics.
This section should exist for most manuals.
Cross-references should conventionally be ordered first by section, then
-alphabetically.
+alphabetically (ignoring case).
.Pp
References to other documentation concerning the topic of the manual page,
for example authoritative books or journal articles, may also be
.Ss Document preamble and NAME section macros
.Bl -column "Brq, Bro, Brc" description
.It Sx \&Dd Ta document date: Cm $\&Mdocdate$ | Ar month day , year
-.It Sx \&Dt Ta document title: Ar TITLE section Op Ar volume | arch
+.It Sx \&Dt Ta document title: Ar TITLE section Op Ar arch
.It Sx \&Os Ta operating system version: Op Ar system Op Ar version
.It Sx \&Nm Ta document name (one argument)
.It Sx \&Nd Ta document description (one line)
.Op Fl compact
.It Sx \&D1 Ta indented display (one line)
.It Sx \&Dl Ta indented literal display (one line)
+.It Sx \&Ql Ta in-line literal display: Ql text
.It Sx \&Bl , \&El Ta list block:
.Fl Ar type
.Op Fl width Ar val
.It Sx \&Pf Ta prefix, no following horizontal space (one argument)
.It Sx \&Ns Ta roman font, no preceding horizontal space (no arguments)
.It Sx \&Ap Ta apostrophe without surrounding whitespace (no arguments)
-.It Sx \&Sm Ta switch horizontal spacing mode: Cm on | off
+.It Sx \&Sm Ta switch horizontal spacing mode: Op Cm on | off
.It Sx \&Bk , \&Ek Ta keep block: Fl words
.It Sx \&br Ta force output line break in text mode (no arguments)
.It Sx \&sp Ta force vertical space: Op Ar height
.It Sx \&Cd Ta kernel configuration declaration (>0 arguments)
.It Sx \&Ad Ta memory address (>0 arguments)
.It Sx \&Ms Ta mathematical symbol (>0 arguments)
-.It Sx \&Tn Ta tradename (>0 arguments)
.El
.Ss Physical markup
.Bl -column "Brq, Bro, Brc" description
.It Sx \&Dq , \&Do , \&Dc Ta enclose in typographic double quotes: Dq text
.It Sx \&Qq , \&Qo , \&Qc Ta enclose in typewriter double quotes: Qq text
.It Sx \&Sq , \&So , \&Sc Ta enclose in single quotes: Sq text
-.It Sx \&Ql Ta single-quoted literal text: Ql text
.It Sx \&Pq , \&Po , \&Pc Ta enclose in parentheses: Pq text
.It Sx \&Bq , \&Bo , \&Bc Ta enclose in square brackets: Bq text
.It Sx \&Brq , \&Bro , \&Brc Ta enclose in curly braces: Brq text
.It Sx \&Ex Fl std Ta standard command exit values: Op Ar utility ...
.It Sx \&Rv Fl std Ta standard function return values: Op Ar function ...
.It Sx \&St Ta reference to a standards document (one argument)
-.It Sx \&Ux Ta Ux
.It Sx \&At Ta At
.It Sx \&Bx Ta Bx
.It Sx \&Bsx Ta Bsx
.Sx \&Dx ,
.Sx \&Fx ,
.Sx \&Nx ,
-.Sx \&Ox ,
and
-.Sx \&Ux .
+.Sx \&Ox .
.Ss \&Bc
Close a
.Sx \&Bo
must be one of the following:
.Bl -tag -width 13n -offset indent
.It Fl centered
-Produce one output line from each input line, and centre-justify each line.
+Produce one output line from each input line, and center-justify each line.
Using this display type is not recommended; many
.Nm
implementations render it poorly.
.Cm right ,
which justifies to the right margin; or
.Cm center ,
-which aligns around an imagined centre axis.
+which aligns around an imagined center axis.
.It
A macro invocation, which selects a predefined width
associated with that macro.
.Fl width
and
.Fl offset
-arguments accept scaling widths as described in
-.Xr roff 7
+arguments accept macro names as described for
+.Sx \&Bd
+.Fl offset ,
+scaling widths as described in
+.Xr roff 7 ,
or use the length of the given string.
The
.Fl offset
A columnated list.
The
.Fl width
-argument has no effect; instead, each argument specifies the width
-of one column, using either the scaling width syntax described in
-.Xr roff 7
-or the string length of the argument.
+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
.Sx \&Dx ,
.Sx \&Fx ,
.Sx \&Nx ,
-.Sx \&Ox ,
and
-.Sx \&Ux .
+.Sx \&Ox .
.Ss \&Bt
+Supported only for compatibility, do not use this in new manuals.
Prints
.Dq is currently in beta test.
.Ss \&Bx
.Sx \&Dx ,
.Sx \&Fx ,
.Sx \&Nx ,
-.Sx \&Ox ,
and
-.Sx \&Ux .
+.Sx \&Ox .
.Ss \&Cd
Kernel configuration declaration.
This denotes strings accepted by
and
.Sx \&Dl .
.Ss \&Db
-Switch debugging mode.
-Its syntax is as follows:
-.Pp
-.D1 Pf \. Sx \&Db Cm on | off
-.Pp
-This macro is ignored by
-.Xr mandoc 1 .
+This macro is obsolete.
+No replacement is needed.
+It is ignored by
+.Xr mandoc 1
+and groff including its arguments.
+It was formerly used to toggle a debugging mode.
.Ss \&Dc
Close a
.Sx \&Do
block.
Does not have any tail arguments.
.Ss \&Dd
-Document date.
+Document date for display in the page footer.
This is the mandatory first macro of any
.Nm
manual.
.Dq $\&Mdocdate$
can be given as an argument.
.It
-A few alternative date formats are accepted as well
-and converted to the standard form.
+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
and
.Sx \&Os .
.Ss \&Dl
-One-line intended display.
+One-line indented display.
This is formatted as literal text and is useful for commands and
invocations.
It is followed by a newline.
.Dl \&.Dl % mandoc mdoc.7 \e(ba less
.Pp
See also
+.Sx \&Ql ,
.Sx \&Bd
+.Fl literal ,
and
.Sx \&D1 .
.Ss \&Do
and
.Sx \&Do .
.Ss \&Dt
-Document title.
+Document title for display in the page header.
This is the mandatory second macro of any
.Nm
file.
Its syntax is as follows:
.Bd -ragged -offset indent
.Pf \. Sx \&Dt
-.Oo
-.Ar title
-.Oo
+.Ar TITLE
.Ar section
-.Op Ar volume
.Op Ar arch
-.Oc
-.Oc
.Ed
.Pp
Its arguments are as follows:
-.Bl -tag -width Ds -offset Ds
-.It Ar title
+.Bl -tag -width section -offset 2n
+.It Ar TITLE
The document's title (name), defaulting to
-.Dq UNKNOWN
+.Dq UNTITLED
if unspecified.
-It should be capitalised.
+To achieve a uniform appearance of page header lines,
+it should by convention be all caps.
.It Ar section
The manual section.
This may be one of
.Cm 1
-.Pq utilities ,
+.Pq General Commands ,
.Cm 2
-.Pq system calls ,
+.Pq System Calls ,
.Cm 3
-.Pq libraries ,
+.Pq Library Functions ,
.Cm 3p
-.Pq Perl libraries ,
+.Pq Perl Library ,
.Cm 4
-.Pq devices ,
+.Pq Device Drivers ,
.Cm 5
-.Pq file formats ,
+.Pq File Formats ,
.Cm 6
-.Pq games ,
+.Pq Games ,
.Cm 7
-.Pq miscellaneous ,
+.Pq Miscellaneous Information ,
.Cm 8
-.Pq system utilities ,
-.Cm 9
-.Pq kernel functions ,
-.Cm X11
-.Pq X Window System ,
-.Cm X11R6
-.Pq X Window System ,
-.Cm unass
-.Pq unassociated ,
-.Cm local
-.Pq local system ,
-.Cm draft
-.Pq draft manual ,
+.Pq System Manager's Manual ,
or
-.Cm paper
-.Pq paper .
+.Cm 9
+.Pq Kernel Developer's Manual .
It should correspond to the manual's filename suffix and defaults to
-.Cm 1
-if unspecified.
-.It Ar volume
-This overrides the volume inferred from
-.Ar section .
-This field is optional, and if specified, must be one of
-.Cm USD
-.Pq users' supplementary documents ,
-.Cm PS1
-.Pq programmers' supplementary documents ,
-.Cm AMD
-.Pq administrators' supplementary documents ,
-.Cm SMM
-.Pq system managers' manuals ,
-.Cm URM
-.Pq users' reference manuals ,
-.Cm PRM
-.Pq programmers' reference manuals ,
-.Cm KM
-.Pq kernel manuals ,
-.Cm IND
-.Pq master index ,
-.Cm MMI
-.Pq master index ,
-.Cm LOCAL
-.Pq local manuals ,
-.Cm LOC
-.Pq local manuals ,
-or
-.Cm CON
-.Pq contributed manuals .
+the empty string if unspecified.
.It Ar arch
This specifies the machine architecture a manual page applies to,
where relevant, for example
.Cm i386 ,
or
.Cm sparc64 .
-The list of supported architectures varies by operating system.
-For the full list of all architectures recognized by
-.Xr mandoc 1 ,
-see the file
-.Pa arch.in
-in the source distribution.
+The list of valid architectures varies by operating system.
.El
.Pp
Examples:
.Dl \&.Dt FOO 1
-.Dl \&.Dt FOO 4 KM
.Dl \&.Dt FOO 9 i386
.Pp
See also
.Sx \&Bx ,
.Sx \&Fx ,
.Sx \&Nx ,
-.Sx \&Ox ,
and
-.Sx \&Ux .
+.Sx \&Ox .
.Ss \&Ec
Close a scope started by
.Sx \&Eo .
and
.Sx \&It .
.Ss \&Em
-Denotes text that should be
-.Em emphasised .
-Note that this is a presentation term and should not be used for
-stylistically decorating technical terms.
-Depending on the output device, this is usually represented
-using an italic font or underlined characters.
+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
+.Sx \&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,
+.Sx \&Sy
+and
+.Sx \&Ar
+are preferred, respectively.
.Pp
Examples:
-.Dl \&.Em Warnings!
-.Dl \&.Em Remarks :
+.Bd -literal -compact -offset indent
+Selected lines are those
+\&.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
.Pp
See also
.Sx \&Bf ,
and
.Sx \&Sy .
.Ss \&En
-This macro is obsolete and not implemented in
-.Xr mandoc 1 .
+This macro is obsolete.
+Use
+.Sx \&Eo
+or any of the other enclosure macros.
+.Pp
+It encloses its argument in the delimiters specified by the last
+.Sx \&Es
+macro.
.Ss \&Eo
An arbitrary enclosure.
Its syntax is as follows:
.Sx \&Dv
for general constants.
.Ss \&Es
-This macro is obsolete and not implemented.
+This macro is obsolete.
+Use
+.Sx \&Eo
+or any of the other enclosure macros.
+.Pp
+It takes two arguments, defining the delimiters to be used by subsequent
+.Sx \&En
+macros.
.Ss \&Ev
Environmental variables such as those specified in
.Xr environ 7 .
See also
.Sx \&Rv .
.Ss \&Fa
-Function argument.
+Function argument or parameter.
Its syntax is as follows:
.Bd -ragged -offset indent
.Pf \. Sx \&Fa
-.Op Cm argtype
-.Cm argname
+.Qo
+.Op Ar argtype
+.Op Ar argname
+.Qc Ar \&...
.Ed
.Pp
-This may be invoked for names with or without the corresponding type.
-It is also used to specify the field name of a structure.
+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
+.Sx \&Fa
+macro.
+.Pp
+This macro is also used to specify the field name of a structure.
+.Pp
Most often, the
.Sx \&Fa
macro is used in the
.Em SYNOPSIS
within
.Sx \&Fo
-section when documenting multi-line function prototypes.
+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
Examples:
.Dl \&.Fa \(dqconst char *p\(dq
.Dl \&.Fa \(dqint a\(dq \(dqint b\(dq \(dqint c\(dq
-.Dl \&.Fa foo
+.Dl \&.Fa \(dqchar *\(dq size_t
.Pp
See also
.Sx \&Fo .
A function name.
Its syntax is as follows:
.Bd -ragged -offset indent
-.Pf \. Ns Sx \&Fn
+.Pf . Sx \&Fn
.Op Ar functype
.Ar funcname
.Op Oo Ar argtype Oc Ar argname
.br
.Pf \. Sx \&Fo Ar funcname
.br
-.Pf \. Sx \&Fa Oo Ar argtype Oc Ar argname
+.Pf \. Sx \&Fa Qq Ar argtype Ar argname
.br
\&.\.\.
.br
and
.Sx \&Ft .
.Ss \&Fr
-This macro is obsolete and not implemented in
-.Xr mandoc 1 .
+This macro is obsolete.
+No replacement markup is needed.
.Pp
-It was used to show function return values.
-The syntax was:
-.Pp
-.Dl Pf . Sx \&Fr Ar value
+It was used to show numerical function return values in an italic font.
.Ss \&Ft
A function type.
Its syntax is as follows:
.Sx \&Bx ,
.Sx \&Dx ,
.Sx \&Nx ,
-.Sx \&Ox ,
and
-.Sx \&Ux .
+.Sx \&Ox .
.Ss \&Hf
This macro is not implemented in
.Xr mandoc 1 .
.Sx \&Ic
macro is used when referring to specific instructions.
.Ss \&In
-An
-.Dq include
-file.
+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
-.Dq #include ,
+.Qq #include ,
and a blank line is inserted in front if there is a preceding
function declaration.
-This is most often used in section 2, 3, and 9 manual pages.
+In other sections, it only encloses its argument in angle brackets
+and causes no line break.
.Pp
Examples:
.Dl \&.In sys/types.h
list is the most complicated.
Its syntax is as follows:
.Pp
-.D1 Pf \. Sx \&It Ar cell Op <TAB> Ar cell ...
.D1 Pf \. Sx \&It Ar cell Op Sx \&Ta Ar cell ...
+.D1 Pf \. Sx \&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 tabs or by the special
+Cells within the line are delimited by the special
.Sx \&Ta
-block macro.
+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
.Sx \&It
line itself; on following lines, only the
line.
For example,
.Pp
-.Dl .It \(dqcol1 ; <TAB> col2 ;\(dq \&;
+.Dl .It \(dqcol1 ,\& <TAB> col2 ,\(dq \&;
.Pp
-will preserve the semicolon whitespace except for the last.
+will preserve the whitespace before both commas,
+but not the whitespace before the semicolon.
.Pp
See also
.Sx \&Bl .
.Dl \&.An Kristaps Dzonsons \&Aq \&Mt kristaps@bsd.lv
.Ss \&Nd
A one line description of the manual's content.
-This may only be invoked in the
-.Em SYNOPSIS
-section subsequent the
-.Sx \&Nm
-macro.
+This is the mandatory last macro of the
+.Em NAME
+section and not appropriate for other sections.
.Pp
Examples:
.Dl Pf . Sx \&Nd mdoc language reference
.Sx \&Bx ,
.Sx \&Dx ,
.Sx \&Fx ,
-.Sx \&Ox ,
and
-.Sx \&Ux .
+.Sx \&Ox .
.Ss \&Oc
Close multi-line
.Sx \&Oo
See also
.Sx \&Oo .
.Ss \&Os
-Document operating system version.
+Operating system version for display in the page footer.
This is the mandatory third macro of
any
.Nm
The optional
.Ar system
parameter specifies the relevant operating system or environment.
-Left unspecified, it defaults to the local operating system version.
-This is the suggested form.
+It is suggested to leave it unspecified, in which case
+.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
Examples:
.Dl \&.Os
and
.Sx \&Dt .
.Ss \&Ot
-This macro is obsolete and not implemented in
-.Xr mandoc 1 .
+This macro is obsolete.
+Use
+.Sx \&Ft
+instead; with
+.Xr mandoc 1 ,
+both have the same effect.
.Pp
Historical
.Nm
.Sx \&Bx ,
.Sx \&Dx ,
.Sx \&Fx ,
-.Sx \&Nx ,
and
-.Sx \&Ux .
+.Sx \&Nx .
.Ss \&Pa
An absolute or relative file system path, or a file or directory name.
If an argument is not provided, the character
Close parenthesised context opened by
.Sx \&Po .
.Ss \&Pf
-Removes the space between its argument
-.Pq Dq prefix
-and the following macro.
+Removes the space between its argument and the following macro.
Its syntax is as follows:
.Pp
.D1 .Pf Ar prefix macro arguments ...
.Pp
This is equivalent to:
.Pp
-.D1 .No Ar prefix No \&Ns Ar macro arguments ...
+.D1 .No \e& Ns Ar prefix No \&Ns Ar macro arguments ...
+.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
Close quoted context opened by
.Sx \&Qo .
.Ss \&Ql
-Format a single-quoted literal.
+In-line literal display.
+This can for example be used for complete command invocations and
+for multi-word code fragments when more specific markup is not
+appropriate and an indented display is not desired.
+While
+.Xr mandoc 1
+always encloses the arguments in single quotes, other formatters
+usually omit the quotes on non-terminal output devices when the
+arguments have three or more characters.
+.Pp
See also
-.Sx \&Qq
+.Sx \&Dl
and
-.Sx \&Sq .
+.Sx \&Bd
+.Fl literal .
.Ss \&Qo
Multi-line version of
.Sx \&Qq .
\&.%A J. D. Ullman
\&.%B Introduction to Automata Theory, Languages, and Computation
\&.%I Addison-Wesley
-\&.%C Reading, Massachusettes
+\&.%C Reading, Massachusetts
\&.%D 1979
\&.Re
.Ed
Switches the spacing mode for output generated from macros.
Its syntax is as follows:
.Pp
-.D1 Pf \. Sx \&Sm Cm on | off
+.D1 Pf \. Sx \&Sm Op Cm on | off
.Pp
By default, spacing is
.Cm on .
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
+.Sx \&Sm
+macro toggles the spacing mode.
+Using this is not recommended because it makes the code harder to read.
.Ss \&So
Multi-line version of
.Sx \&Sq .
.Pp
.It \-isoC-99
.St -isoC-99
-.It \-ansiC-99
-.St -ansiC-99
.br
The second major version of the C language standard.
.Pp
.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 and is also called SUSv1.
+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
.br
Networking APIs, including sockets.
.Pp
-.It \-xpg4.3
-.St -xpg4.3
-.Pp
.It \-svid4
.St -svid4 ,
.br
.Pp
.It \-xns5
.St -xns5
-.It \-xns5.2d2.0
-.St -xns5.2d2.0
.It \-xns5.2
.St -xns5.2
-.Pp
-.It \-p1387.2
-.St -p1387.2
-.It \-p1387.2-95
-.St -p1387.2-95
-.br
-POSIX software administration.
.El
-.It Single UNIX Specification version 3 and related standards
-.Pp
-.Bl -tag -width "-p1003.1g-2000X" -compact
-.It \-p1003.1d-99
-.St -p1003.1d-99
-.br
-Additional real-time extensions.
-.Pp
-.It \-p1003.1j-2000
-.St -p1003.1j-2000
-.br
-Advanced real-time extensions.
-.Pp
-.It \-p1003.1q-2000
-.St -p1003.1q-2000
-.br
-Amendment 7: Tracing [C Language].
+.It Single UNIX Specification version 3
.Pp
+.Bl -tag -width "-p1003.1-2001" -compact
.It \-p1003.1-2001
.St -p1003.1-2001
.It \-susv3
.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 SUSv4 and
+This standard is also called
X/Open Portability Guide version 7.
.Pp
.It \-p1003.1-2013
and
.Sx \&Ss .
.Ss \&Sy
-Format enclosed arguments in symbolic
-.Pq Dq boldface .
-Note that this is a presentation term and should not be used for
-stylistically decorating technical terms.
+Request a boldface font.
+.Pp
+This is most often used to indicate importance or seriousness (not to be
+confused with stress emphasis, see
+.Sx \&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
.Pp
See also
.Sx \&Bf ,
lists; can only be used below
.Sx \&It .
.Ss \&Tn
-Format a tradename.
-.Pp
-Since this macro is often implemented to use a small caps font,
-it has historically been used for acronyms (like ASCII) as well.
-Such usage is not recommended because it would use the same macro
-sometimes for semantical annotation, sometimes for physical formatting.
-.Pp
-Examples:
-.Dl \&.Tn IBM
+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.
.Ss \&Ud
+Supported only for compatibility, do not use this in new manuals.
Prints out
.Dq currently under development.
.Ss \&Ux
-Format the
-.Ux
-name.
-Accepts no argument.
-.Pp
-Examples:
-.Dl \&.Ux
-.Pp
-See also
-.Sx \&At ,
-.Sx \&Bsx ,
-.Sx \&Bx ,
-.Sx \&Dx ,
-.Sx \&Fx ,
-.Sx \&Nx ,
-and
-.Sx \&Ox .
+Supported only for compatibility, do not use this in new manuals.
+Prints out
+.Dq Ux .
.Ss \&Va
A variable name.
.Pp
Examples:
.Dl \&.Va foo
.Dl \&.Va const char *bar ;
+.Pp
+For function arguments and parameters, use
+.Sx \&Fa
+instead.
+For declarations of global variables in the
+.Em SYNOPSIS
+section, use
+.Sx \&Vt .
.Ss \&Vt
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.
and a blank line is inserted in front if there is a preceding
function definition or include directive.
.Pp
-Note that this should not be confused with
-.Sx \&Ft ,
-which is used for function return types.
-.Pp
Examples:
.Dl \&.Vt unsigned char
.Dl \&.Vt extern const char * const sys_signame[] \&;
.Pp
+For parameters in function prototypes, use
+.Sx \&Fa
+instead, for function return types
+.Sx \&Ft ,
+and for variable names outside the
+.Em SYNOPSIS
+section
+.Sx \&Va ,
+even when including a type with the name.
See also
-.Sx MANUAL STRUCTURE
-and
-.Sx \&Va .
+.Sx MANUAL STRUCTURE .
.Ss \&Xc
Close a scope opened by
.Sx \&Xo .
.Pq Qq cross-reference .
Its syntax is as follows:
.Pp
-.D1 Pf \. Sx \&Xr Ar name Op section
+.D1 Pf \. Sx \&Xr Ar name section
.Pp
Cross reference the
.Ar name
and
.Ar section
-number of another man page;
-omitting the section number is rarely useful.
+number of another man page.
.Pp
Examples:
.Dl \&.Xr mandoc 1
.It Sx \&D1 Ta \&No Ta \&Yes
.It Sx \&Dl Ta \&No Ta Yes
.It Sx \&Dq Ta Yes Ta Yes
+.It Sx \&En 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 \&Dv Ta Yes Ta Yes Ta >0
.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 \&Es Ta Yes Ta Yes Ta 2
.It Sx \&Ev Ta Yes Ta Yes Ta >0
.It Sx \&Ex Ta \&No Ta \&No Ta n
.It Sx \&Fa Ta Yes Ta Yes Ta >0
.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 \&Fr Ta Yes Ta Yes Ta >0
.It Sx \&Ft Ta Yes Ta Yes Ta >0
.It Sx \&Fx Ta Yes Ta Yes Ta n
.It Sx \&Hf Ta \&No Ta \&No Ta n
.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 \&Ot Ta Yes Ta Yes Ta >0
.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 \&Sm Ta \&No Ta \&No Ta <2
.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 \&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 \&Xr Ta Yes Ta Yes Ta 2
.It Sx \&br Ta \&No Ta \&No Ta 0
.It Sx \&sp Ta \&No Ta \&No Ta 1
.El
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 ] ) ."
.D1 Fl a ( b | c \*(Ba d ) e
.Pp
This applies to both opening and closing delimiters,
-and also to the middle delimiter:
+and also to the middle delimiter, which does not suppress spacing:
.Pp
.Bl -tag -width Ds -offset indent -compact
.It \&|
.Ql \ef
font escape sequences is never required.
.Sh COMPATIBILITY
-This section documents compatibility between mandoc and other
-troff implementations, at this time limited to GNU troff
+This section provides an incomplete list of compatibility issues
+between mandoc and GNU troff
.Pq Qq groff .
-The term
-.Qq historic groff
-refers to groff versions before 1.17,
-which featured a significant update of the
-.Pa doc.tmac
-file.
-.Pp
-Heirloom troff, the other significant troff implementation accepting
-\-mdoc, is similar to historic groff.
.Pp
The following problematic behaviour is found in groff:
-.ds hist (Historic groff only.)
.Pp
.Bl -dash -compact
.It
-Display macros
-.Po
-.Sx \&Bd ,
-.Sx \&Dl ,
-and
-.Sx \&D1
-.Pc
-may not be nested.
-\*[hist]
-.It
-.Sx \&At
-with unknown arguments produces no output at all.
-\*[hist]
-Newer groff and mandoc print
-.Qq AT&T UNIX
-and the arguments.
-.It
-.Sx \&Bl Fl column
-does not recognise trailing punctuation characters when they immediately
-precede tabulator characters, but treats them as normal text and
-outputs a space before them.
-.It
-.Sx \&Bd Fl ragged compact
-does not start a new line.
-\*[hist]
-.It
.Sx \&Dd
with non-standard arguments behaves very strangely.
When there are three arguments, they are printed verbatim.
.Dq Epoch
is printed.
.It
-.Sx \&Fl
-does not print a dash for an empty argument.
-\*[hist]
-.It
-.Sx \&Fn
-does not start a new line unless invoked as the line macro in the
-.Em SYNOPSIS
-section.
-\*[hist]
-.It
-.Sx \&Fo
-with
-.Pf non- Sx \&Fa
-children causes inconsistent spacing between arguments.
-In mandoc, a single space is always inserted between arguments.
-.It
-.Sx \&Ft
-in the
-.Em SYNOPSIS
-causes inconsistent vertical spacing, depending on whether a prior
-.Sx \&Fn
-has been invoked.
-See
-.Sx \&Ft
-and
-.Sx \&Fn
-for the normalised behaviour in mandoc.
-.It
-.Sx \&In
-ignores additional arguments and is not treated specially in the
-.Em SYNOPSIS .
-\*[hist]
-.It
-.Sx \&It
-sometimes requires a
-.Fl nested
-flag.
-\*[hist]
-In new groff and mandoc, any list may be nested by default and
-.Fl enum
-lists will restart the sequence only for the sub-list.
-.It
-.Sx \&Li
-followed by a delimiter is incorrectly used in some manuals
-instead of properly quoting that character, which sometimes works with
-historic groff.
-.It
.Sx \&Lk
only accepts a single link-name argument; the remainder is misformatted.
.It
can only be called by other macros, but not at the beginning of a line.
.It
.Sx \&%C
-is not implemented.
-.It
-Historic groff only allows up to eight or nine arguments per macro input
-line, depending on the exact situation.
-Providing more arguments causes garbled output.
-The number of arguments on one input line is not limited with mandoc.
-.It
-Historic groff has many un-callable macros.
-Most of these (excluding some block-level macros) are callable
-in new groff and mandoc.
-.It
-.Sq \(ba
-(vertical bar) is not fully supported as a delimiter.
-\*[hist]
+is not implemented (up to and including groff-1.22.2).
.It
.Sq \ef
.Pq font face
and
-.Sq \ef
+.Sq \eF
.Pq font family face
.Sx Text Decoration
escapes behave irregularly when specified within line-macro scopes.
.Bl -dash -compact
.It
.Sx \&Bd
-.Fl file Ar file .
+.Fl file Ar file
+is unsupported for security reasons.
+.It
+.Sx \&Bd
+.Fl filled
+does not adjust the right margin, but is an alias for
+.Sx \&Bd
+.Fl ragged .
+.It
+.Sx \&Bd
+.Fl literal
+does not use a literal font, but is an alias for
+.Sx \&Bd
+.Fl unfilled .
.It
.Sx \&Bd
.Fl offset Cm center
and
-.Fl offset Cm right .
-Groff does not implement centred and flush-right rendering either,
+.Fl offset Cm right
+don't work.
+Groff does not implement centered and flush-right rendering either,
but produces large indentations.
-.It
-The
-.Sq \eh
-.Pq horizontal position ,
-.Sq \ev
-.Pq vertical position ,
-.Sq \em
-.Pq text colour ,
-.Sq \eM
-.Pq text filling colour ,
-.Sq \ez
-.Pq zero-length character ,
-.Sq \ew
-.Pq string length ,
-.Sq \ek
-.Pq horizontal position marker ,
-.Sq \eo
-.Pq text overstrike ,
-and
-.Sq \es
-.Pq text size
-escape sequences are all discarded in mandoc.
-.It
-The
-.Sq \ef
-scaling unit is accepted by mandoc, but rendered as the default unit.
-.It
-In quoted literals, groff allows pairwise double-quotes to produce a
-standalone double-quote in formatted output.
-This is not supported by mandoc.
.El
.Sh SEE ALSO
.Xr man 1 ,
.Xr mandoc_char 7 ,
.Xr roff 7 ,
.Xr tbl 7
+.Pp
+The web page
+.Lk http://mdocml.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
git.ckatri.com / mandoc.git / blobdiff