mandoc/mdoc.7 - diff

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Diff for /mandoc/mdoc.7 between version 1.233 and 1.268

version 1.233, 2014/08/08 01:52:40

version 1.268, 2017/07/05 12:25:17

Line 1

.\" $Id$

.\"

.\" Permission to use, copy, modify, and distribute this software for any

.\" purpose with or without fee is hereby granted, provided that the above

Line 304 Print verbose information.

\&.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

Line 388 See

Line 393 See

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

Line 433 in the alphabetical

Line 438 in the alphabetical

.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)

Line 454 in the alphabetical

Line 459 in the alphabetical

.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

Line 468 in the alphabetical

Line 474 in the alphabetical

.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

.El

.Ss Semantic markup for command line utilities:

.Ss Semantic markup for command line utilities

.Bl -column "Brq, Bro, Brc" description

.It Sx \&Nm Ta start a SYNOPSIS block with the name of a utility

.It Sx \&Fl Ta command line options (flags) (>=0 arguments)

Line 484 in the alphabetical

Line 488 in the alphabetical

.It Sx \&Ev Ta environmental variable (>0 arguments)

.It Sx \&Pa Ta file system path (>=0 arguments)

.El

.Ss Semantic markup for function libraries:

.Ss Semantic markup for function libraries

.Bl -column "Brq, Bro, Brc" description

.It Sx \&Lb Ta function library (one argument)

.It Sx \&In Ta include file (one argument)

Line 505 in the alphabetical

Line 509 in the alphabetical

.It Sx \&Er Ta error constant (>0 arguments)

.It Sx \&Ev Ta environmental variable (>0 arguments)

.El

.Ss Various semantic markup:

.Ss Various semantic markup

.Bl -column "Brq, Bro, Brc" description

.It Sx \&An Ta author name (>0 arguments)

.It Sx \&Lk Ta hyperlink: Ar uri Op Ar name

Line 528 in the alphabetical

Line 532 in the alphabetical

.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

Line 732 A version of

Line 735 A version of

.At .

.It Cm III

.At III .

.It Cm V[.[1-4]]?

.It Cm V | V.[1-4]

A version of

.At V .

.El

Line 777 The

Line 780 The

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.

Line 822 which has no effect;

Line 825 which has no effect;

.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.

Line 937 The

Line 940 The

.Fl width

and

.Fl offset

arguments accept scaling widths as described in

arguments accept macro names as described for

.Xr roff 7

.Sx \&Bd

.Fl offset ,

scaling widths as described in

.Xr roff 7 ,

or use the length of the given string.

The

.Fl offset

Line 966 argument.

Line 972 argument.

A columnated list.

The

.Fl width

argument has no effect; instead, each argument specifies the width

argument has no effect; instead, the string length of each argument

of one column, using either the scaling width syntax described in

specifies the width of one column.

.Xr roff 7

or the string length of the argument.

If the first line of the body of a

.Fl column

list is not an

Line 1182 See also

Line 1186 See also

and

.Sx \&Dl .

.Ss \&Db

Switch debugging mode.

This macro is obsolete.

Its syntax is as follows:

No replacement is needed.

.Pp

It is ignored by

.D1 Pf \. Sx \&Db Cm on | off

.Xr mandoc 1

.Pp

and groff including its arguments.

This macro is ignored by

It was formerly used to toggle a debugging mode.

.Xr mandoc 1 .

.Ss \&Dc

Close a

.Sx \&Do

Line 1245 See also

Line 1248 See also

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.

Line 1254 Examples:

Line 1257 Examples:

.Dl \&.Dl % mandoc mdoc.7 \e(ba less

.Pp

See also

.Sx \&Ql ,

.Sx \&Bd

.Fl literal ,

and

.Sx \&D1 .

.Ss \&Do

Line 1297 Its syntax is as follows:

Line 1302 Its syntax is as follows:

.Pf \. Sx \&Dt

.Ar TITLE

.Ar section

.Op Ar volume | arch

.Op Ar arch

.Ed

.Pp

Its arguments are as follows:

Line 1312 it should by convention be all caps.

Line 1317 it should by convention be all caps.

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 ,

.Pq System Manager's Manual ,

.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 ,

.Cm paper

.Cm 9

.Pq paper .

.Pq Kernel Developer's Manual .

It should correspond to the manual's filename suffix and defaults to

the empty string 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 ,

.Cm CON

.Pq contributed manuals .

.It Ar arch

This specifies the machine architecture a manual page applies to,

where relevant, for example

Line 1383 where relevant, for example

Line 1347 where relevant, for example

.Cm i386 ,

.Cm sparc64 .

The list of supported architectures varies by operating system.

The list of valid 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.

.El

.Pp

Examples:

.Dl \&.Dt FOO 1

.Dl \&.Dt FOO 4 KM

.Dl \&.Dt FOO 9 i386

.Pp

See also

Line 1467 See also

Line 1425 See also

and

.Sx \&It .

.Ss \&Em

Denotes text that should be

Request an italic font.

.Em emphasised .

If the output device does not provide that, underline.

Note that this is a presentation term and should not be used for

stylistically decorating technical terms.

Depending on the output device, this is usually represented

using an italic font or underlined characters.

.Pp

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!

.Bd -literal -compact -offset indent

.Dl \&.Em Remarks :

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 ,

Line 1557 arguments are treated as separate utilities.

Line 1528 arguments are treated as separate utilities.

See also

.Sx \&Rv .

.Ss \&Fa

Function argument.

Function argument or parameter.

Its syntax is as follows:

.Bd -ragged -offset indent

.Pf \. Sx \&Fa

Line 1652 See also

Line 1623 See also

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

Line 1788 is preferred for displaying code; the

Line 1759 is preferred for displaying code; the

.Sx \&Ic

macro is used when referring to specific instructions.

.Ss \&In

The name of an include file.

.Dq include

This macro is most often used in section 2, 3, and 9 manual pages.

file.

.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

Line 1855 The

Line 1827 The

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

.Sx \&Ta

macro can be used to delimit cells, and

macro can be used to delimit cells, and portability requires that

.Sx \&Ta

is only recognised as a macro when called by other macros,

is called by other macros: some parsers do not recognize it when

not as the first macro on a line.

it appears as the first macro on a line.

.Pp

Note that quoted strings may span tab-delimited cells on an

.Sx \&It

line.

For example,

.Pp

.Dl .It \(dqcol1 ; <TAB> col2 ;\(dq \&;

.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 .

Line 1959 Examples:

Line 1943 Examples:

.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

This is the mandatory last macro of the

.Em SYNOPSIS

.Em NAME

section subsequent the

section and not appropriate for other sections.

.Sx \&Nm

macro.

.Pp

Examples:

.Dl Pf . Sx \&Nd mdoc language reference

Line 2120 Its syntax is as follows:

Line 2102 Its syntax is as follows:

The optional

.Ar system

parameter specifies the relevant operating system or environment.

Left unspecified, it defaults to the local operating system version.

It is suggested to leave it unspecified, in which case

This is the suggested form.

.Xr mandoc 1

uses its

.Fl Ios

argument or, if that isn't specified either,

.Fa sysname

and

.Fa release

as returned by

.Xr uname 3 .

.Pp

Examples:

.Dl \&.Os

Line 2178 See also

Line 2168 See also

Close parenthesised context opened by

.Sx \&Po .

.Ss \&Pf

Removes the space between its argument

Removes the space between its argument and the following macro.

.Pq Dq prefix

and the following macro.

Its syntax is as follows:

.Pp

.D1 .Pf Ar prefix macro arguments ...

.Pp

This is equivalent to:

.Pp

.D1 .No Ar prefix No \&Ns Ar macro arguments ...

.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

Line 2225 See also

Line 2219 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 .

Line 2280 Examples:

Line 2284 Examples:

\&.%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

Line 2335 and

Line 2339 and

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 .

Line 2344 When switched

Line 2348 When switched

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 .

Line 2411 The original C standard.

Line 2420 The original C standard.

.Pp

.It \-isoC-99

.St -isoC-99

.It \-ansiC-99

.St -ansiC-99

.br

The second major version of the C language standard.

.Pp

Line 2492 Based on POSIX.1 and POSIX.2, published in 1992.

Line 2499 Based on POSIX.1 and POSIX.2, published in 1992.

.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

Line 2510 The following three refer to parts of it.

Line 2519 The following three refer to parts of it.

.br

Networking APIs, including sockets.

.Pp

.It \-xpg4.3

.St -xpg4.3

.Pp

.It \-svid4

.St -svid4 ,

.br

Line 2539 The following refer to parts of it.

Line 2545 The following refer to parts of it.

.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

.It Single UNIX Specification version 3

.Pp

.Bl -tag -width "-p1003.1g-2000X" -compact

.Bl -tag -width "-p1003.1-2001" -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].

.Pp

.It \-p1003.1-2001

.St -p1003.1-2001

.It \-susv3

Line 2588 The second and last Technical Corrigendum.

Line 2570 The second and last Technical Corrigendum.

.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

.St -p1003.1-2013

.br

This is the first Technical Corrigendum.

.El

.It Other standards

.Pp

Line 2632 See also

Line 2611 See also

and

.Sx \&Ss .

.Ss \&Sy

Format enclosed arguments in symbolic

Request a boldface font.

.Pq Dq boldface .

Note that this is a presentation term and should not be used for

stylistically decorating technical terms.

.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 :

\&.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 ,

.Sx \&Em ,

Line 2668 A variable name.

Line 2661 A variable name.

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.

Line 2684 In the former case, this macro starts a new output lin

Line 2686 In the former case, this macro starts a new output lin

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

.Sx MANUAL STRUCTURE .

and

.Sx \&Va .

.Ss \&Xc

Close a scope opened by

.Sx \&Xo .

Line 2712 Link to another manual

Line 2717 Link to another manual

.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;

number of another man page.

omitting the section number is rarely useful.

.Pp

Examples:

.Dl \&.Xr mandoc 1

.Dl \&.Xr mandoc 1 \&;

.Dl \&.Xr mandoc 1 \&Ns s behaviour

.Ss \&br

Emits a line-break.

This macro should not be used; it is implemented for compatibility with

historical manuals.

.Pp

Consider using

.Sx \&Pp

in the event of natural paragraph breaks.

.Ss \&sp

Emits vertical space.

This macro should not be used; it is implemented for compatibility with

historical manuals.

Its syntax is as follows:

.Pp

.D1 Pf \. Sx \&sp Op Ar height

.Pp

The

.Ar height

argument is a scaling width as described in

.Xr roff 7 .

If unspecified,

.Sx \&sp

asserts a single vertical space.

.Sh MACRO SYNTAX

The syntax of a macro depends on its classification.

In this section,

Line 3022 then the macro accepts an arbitrary number of argument

Line 3003 then the macro accepts an arbitrary number of argument

.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

Line 3031 then the macro accepts an arbitrary number of argument

Line 3012 then the macro accepts an arbitrary number of argument

.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

.Ss Delimiters

When a macro argument consists of one single input character

Line 3051 For many macros, when the leading arguments are openin

Line 3030 For many macros, when the leading arguments are openin

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 ] ) ."

Line 3107 renders as:

Line 3088 renders as:

.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 \&|

Line 3139 Manually switching the font using the

Line 3120 Manually switching the font using the

font escape sequences is never required.

.Sh COMPATIBILITY

This section provides an incomplete list of compatibility issues

between mandoc and other troff implementations, at this time limited

between mandoc and GNU troff

to 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.

Line 3191 but without any arguments the string

Line 3135 but without any arguments the string

.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

Line 3251 can only be called by other macros, but not at the beg

Line 3148 can only be called by other macros, but not at the beg

.Sx \&%C

is not implemented (up to and including groff-1.22.2).

.It

Historic groff only allows up to eight or nine arguments per macro input

line, depending on the exact situation.

Providing more arguments causes garbled output.

The number of arguments on one input line is not limited with mandoc.

.It

Historic groff has many un-callable macros.

Most of these (excluding some block-level macros) are callable

in new groff and mandoc.

.It

.Sq \(ba

(vertical bar) is not fully supported as a delimiter.

\*[hist]

.It

.Sq \ef

.Pq font face

and

Line 3281 The following features are unimplemented in mandoc:

Line 3165 The following features are unimplemented in mandoc:

.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 .

.Fl offset Cm right

Groff does not implement centred and flush-right rendering either,

don't work.

Groff does not implement centered and flush-right rendering either,

but produces large indentations.

.El

.Sh SEE ALSO

Line 3298 but produces large indentations.

Line 3196 but produces large indentations.

.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

CVSweb