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This is groff, produced by makeinfo version 4.8 from ./groff.texinfo.
This manual documents GNU `troff' version 1.19.2.
Copyright (C) 1994-2000, 2001, 2002, 2003, 2004, 2005 Free Software
Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
Version 1.1 or any later version published by the Free Software
Foundation; with no Invariant Sections, with the Front-Cover texts
being `A GNU Manual," and with the Back-Cover Texts as in (a)
below. A copy of the license is included in the section entitled
`GNU Free Documentation License."
(a) The FSF's Back-Cover Text is: `You have freedom to copy and
modify this GNU Manual, like GNU software. Copies published by
the Free Software Foundation raise funds for GNU development."
INFO-DIR-SECTION Typesetting
START-INFO-DIR-ENTRY
* Groff: (groff). The GNU troff document formatting system.
END-INFO-DIR-ENTRY

File: groff, Node: Drawing Requests, Next: Traps, Prev: Page Motions, Up: gtroff Reference
5.23 Drawing Requests
=====================
`gtroff' provides a number of ways to draw lines and other figures on
the page. Used in combination with the page motion commands (see *Note
Page Motions::, for more info), a wide variety of figures can be drawn.
However, for complex drawings these operations can be quite
cumbersome, and it may be wise to use graphic preprocessors like `gpic'
or `ggrn'. *Note gpic::, and *Note ggrn::, for more information.
All drawing is done via escapes.
-- Escape: \l'l'
-- Escape: \l'lg'
Draw a line horizontally. L is the length of the line to be
drawn. If it is positive, start the line at the current location
and draw to the right; its end point is the new current location.
Negative values are handled differently: The line starts at the
current location and draws to the left, but the current location
doesn't move.
L can also be specified absolutely (i.e. with a leading `|') which
draws back to the beginning of the input line. Default scaling
indicator is `m'.
The optional second parameter G is a glyph to draw the line with.
If this second argument is not specified, `gtroff' uses the
underscore glyph, `\[ru]'.
To separate the two arguments (to prevent `gtroff' from
interpreting a drawing glyph as a scaling indicator if the glyph is
represented by a single character) use `\&'.
Here a small useful example:
.de box
\[br]\\$*\[br]\l'|0\[rn]'\l'|0\[ul]'
..
Note that this works by outputting a box rule (a vertical line),
then the text given as an argument and then another box rule.
Finally, the line drawing escapes both draw from the current
location to the beginning of the _input_ line - this works because
the line length is negative, not moving the current point.
-- Escape: \L'l'
-- Escape: \L'lg'
Draw vertical lines. Its parameters are similar to the `\l'
escape, except that the default scaling indicator is `v'. The
movement is downwards for positive values, and upwards for
negative values. The default glyph is the box rule glyph,
`\[br]'. As with the vertical motion escapes, text processing
blindly continues where the line ends.
This is a \L'3v'test.
Here the result, produced with `grotty'.
This is a
|
|
|test.
-- Escape: \D'command arg ...'
The `\D' escape provides a variety of drawing functions. Note
that on character devices, only vertical and horizontal lines are
supported within `grotty'; other devices may only support a subset
of the available drawing functions.
The default scaling indicator for all subcommands of `\D' is `m'
for horizontal distances and `v' for vertical ones. Exceptions
are `\D'f ...'' and `\D't ...'' which use `u' as the default, and
`\D'FX ...'' which arguments are treated similar to the `defcolor'
request.
`\D'l DX DY''
Draw a line from the current location to the relative point
specified by (DX,DY), where positive values mean down and
right, respectively. The end point of the line is the new
current location.
The following example is a macro for creating a box around a
text string; for simplicity, the box margin is taken as a
fixed value, 0.2m.
.de BOX
. nr @wd \w'\\$1'
\h'.2m'\
\h'-.2m'\v'(.2m - \\n[rsb]u)'\
\D'l 0 -(\\n[rst]u - \\n[rsb]u + .4m)'\
\D'l (\\n[@wd]u + .4m) 0'\
\D'l 0 (\\n[rst]u - \\n[rsb]u + .4m)'\
\D'l -(\\n[@wd]u + .4m) 0'\
\h'.2m'\v'-(.2m - \\n[rsb]u)'\
\\$1\
\h'.2m'
..
First, the width of the string is stored in register `@wd'.
Then, four lines are drawn to form a box, properly offset by
the box margin. The registers `rst' and `rsb' are set by the
`\w' escape, containing the largest height and depth of the
whole string.
`\D'c D''
Draw a circle with a diameter of D with the leftmost point at
the current position. After drawing, the current location is
positioned at the rightmost point of the circle.
`\D'C D''
Draw a solid circle with the same parameters and behaviour as
an outlined circle. No outline is drawn.
`\D'e X Y''
Draw an ellipse with a horizontal diameter of X and a vertical
diameter of Y with the leftmost point at the current position.
After drawing, the current location is positioned at the
rightmost point of the ellipse.
`\D'E X Y''
Draw a solid ellipse with the same parameters and behaviour
as an outlined ellipse. No outline is drawn.
`\D'a DX1 DY1 DX2 DY2''
Draw an arc clockwise from the current location through the
two specified relative locations (DX1,DY1) and (DX2,DY2).
The coordinates of the first point are relative to the
current position, and the coordinates of the second point are
relative to the first point. After drawing, the current
position is moved to the final point of the arc.
`\D'~ DX1 DY1 DX2 DY2 ...''
Draw a spline from the current location to the relative point
(DX1,DY1) and then to (DX2,DY2), and so on. The current
position is moved to the terminal point of the drawn curve.
`\D'f N''
Set the shade of gray to be used for filling solid objects
to N; N must be an integer between 0 and 1000, where 0
corresponds solid white and 1000 to solid black, and values
in between correspond to intermediate shades of gray. This
applies only to solid circles, solid ellipses, and solid
polygons. By default, a level of 1000 is used.
Despite of being silly, the current point is moved
horizontally to the right by N.
Don't use this command! It has the serious drawback that it
will be always rounded to the next integer multiple of the
horizontal resolution (the value of the `hor' keyword in the
`DESC' file). Use `\M' (*note Colors::) or `\D'Fg ...''
instead.
`\D'p DX1 DY1 DX2 DY2 ...''
Draw a polygon from the current location to the relative
position (DX1,DY1) and then to (DX2,DY2) and so on. When the
specified data points are exhausted, a line is drawn back to
the starting point. The current position is changed by
adding the sum of all arguments with odd index to the actual
horizontal position and the even ones to the vertical
position.
`\D'P DX1 DY1 DX2 DY2 ...''
Draw a solid polygon with the same parameters and behaviour
as an outlined polygon. No outline is drawn.
Here a better variant of the box macro to fill the box with
some color. Note that the box must be drawn before the text
since colors in `gtroff' are not transparent; the filled
polygon would hide the text completely.
.de BOX
. nr @wd \w'\\$1'
\h'.2m'\
\h'-.2m'\v'(.2m - \\n[rsb]u)'\
\M[lightcyan]\
\D'P 0 -(\\n[rst]u - \\n[rsb]u + .4m) \
(\\n[@wd]u + .4m) 0 \
0 (\\n[rst]u - \\n[rsb]u + .4m) \
-(\\n[@wd]u + .4m) 0'\
\h'.2m'\v'-(.2m - \\n[rsb]u)'\
\M[]\
\\$1\
\h'.2m'
..
`\D't N''
Set the current line thickness to N machine units. A value of
zero selects the smallest available line thickness. A
negative value makes the line thickness proportional to the
current point size (this is the default behaviour of AT&T
`troff').
Despite of being silly, the current point is moved
horizontally to the right by N.
`\D'FSCHEME COLOR_COMPONENTS''
Change current fill color. SCHEME is a single letter
denoting the color scheme: `r' (rgb), `c' (cmy), `k' (cmyk),
`g' (gray), or `d' (default color). The color components use
exactly the same syntax as in the `defcolor' request (*note
Colors::); the command `\D'Fd'' doesn't take an argument.
_No_ position changing!
Examples:
\D'Fg .3' \" same gray as \D'f 700' \D'Fr #0000ff' \"
blue
*Note Graphics Commands::.
-- Escape: \b'string'
"Pile" a sequence of glyphs vertically, and center it vertically
on the current line. Use it to build large brackets and braces.
Here an example how to create a large opening brace:
\b'\[lt]\[bv]\[lk]\[bv]\[lb]'
The first glyph is on the top, the last glyph in STRING is at the
bottom. Note that `gtroff' separates the glyphs vertically by 1m,
and the whole object is centered 0.5m above the current baseline;
the largest glyph width is used as the width for the whole object.
This rather unflexible positioning algorithm doesn't work with
`-Tdvi' since the bracket pieces vary in height for this device.
Instead, use the `eqn' preprocessor.
*Note Manipulating Spacing::, how to adjust the vertical spacing
with the `\x' escape.

File: groff, Node: Traps, Next: Diversions, Prev: Drawing Requests, Up: gtroff Reference
5.24 Traps
==========
"Traps" are locations, which, when reached, call a specified macro.
These traps can occur at a given location on the page, at a given
location in the current diversion, at a blank line, after a certain
number of input lines, or at the end of input.
Setting a trap is also called "planting". It is also said that a
trap is "sprung" if the associated macro is executed.
* Menu:
* Page Location Traps::
* Diversion Traps::
* Input Line Traps::
* Blank Line Traps::
* End-of-input Traps::

File: groff, Node: Page Location Traps, Next: Diversion Traps, Prev: Traps, Up: Traps
5.24.1 Page Location Traps
--------------------------
"Page location traps" perform an action when `gtroff' reaches or passes
a certain vertical location on the page. Page location traps have a
variety of purposes, including:
* setting headers and footers
* setting body text in multiple columns
* setting footnotes
-- Request: .vpt flag
-- Register: \n[.vpt]
Enable vertical position traps if FLAG is non-zero, or disables
them otherwise. Vertical position traps are traps set by the `wh'
or `dt' requests. Traps set by the `it' request are not vertical
position traps. The parameter that controls whether vertical
position traps are enabled is global. Initially vertical position
traps are enabled. The current setting of this is available in the
`.vpt' read-only number register.
Note that a page can't be ejected if `vpt' is set to zero.
-- Request: .wh dist [macro]
Set a page location trap. Non-negative values for DIST set the
trap relative to the top of the page; negative values set the trap
relative to the bottom of the page. Default scaling indicator is
`v'.
MACRO is the name of the macro to execute when the trap is sprung.
If MACRO is missing, remove the first trap (if any) at DIST.
The following is a simple example of how many macro packages set
headers and footers.
.de hd \" Page header
' sp .5i
. tl 'Title''date'
' sp .3i
..
.
.de fo \" Page footer
' sp 1v
. tl ''%''
' bp
..
.
.wh 0 hd \" trap at top of the page
.wh -1i fo \" trap one inch from bottom
A trap at or below the bottom of the page is ignored; it can be
made active by either moving it up or increasing the page length
so that the trap is on the page.
It is possible to have more than one trap at the same location; to
do so, the traps must be defined at different locations, then
moved together with the `ch' request; otherwise the second trap
would replace the first one. Earlier defined traps hide later
defined traps if moved to the same position (the many empty lines
caused by the `bp' request are omitted in the following example):
.de a
. nop a
..
.de b
. nop b
..
.de c
. nop c
..
.
.wh 1i a
.wh 2i b
.wh 3i c
.bp
=> a b c
.ch b 1i
.ch c 1i
.bp
=> a
.ch a 0.5i
.bp
=> a b
-- Register: \n[.t]
A read-only number register holding the distance to the next trap.
If there are no traps between the current position and the bottom
of the page, it contains the distance to the page bottom. In a
diversion, the distance to the page bottom is infinite (the
returned value is the biggest integer which can be represented in
`groff') if there are no diversion traps.
-- Request: .ch macro [dist]
Change the location of a trap. The first argument is the name of
the macro to be invoked at the trap, and the second argument is
the new location for the trap (note that the parameters are
specified in opposite order as in the `wh' request). This is
useful for building up footnotes in a diversion to allow more
space at the bottom of the page for them.
Default scaling indicator for DIST is `v'. If DIST is missing,
the trap is removed.
-- Register: \n[.ne]
The read-only number register `.ne' contains the amount of space
that was needed in the last `ne' request that caused a trap to be
sprung. Useful in conjunction with the `.trunc' register. *Note
Page Control::, for more information.
Since the `.ne' register is only set by traps it doesn't make much
sense to use it outside of trap macros.
-- Register: \n[.trunc]
A read-only register containing the amount of vertical space
truncated by the most recently sprung vertical position trap, or,
if the trap was sprung by an `ne' request, minus the amount of
vertical motion produced by the `ne' request. In other words, at
the point a trap is sprung, it represents the difference of what
the vertical position would have been but for the trap, and what
the vertical position actually is.
Since the `.trunc' register is only set by traps it doesn't make
much sense to use it outside of trap macros.
-- Register: \n[.pe]
A read-only register which is set to 1 while a page is ejected with
the `bp' request (or by the end of input).
Outside of traps this register is always zero. In the following
example, only the second call to `x' is caused by `bp'.
.de x
\&.pe=\\n[.pe]
.br
..
.wh 1v x
.wh 4v x
A line.
.br
Another line.
.br
=> A line.
.pe=0
Another line.
.pe=1
An important fact to consider while designing macros is that
diversions and traps do not interact normally. For example, if a trap
invokes a header macro (while outputting a diversion) which tries to
change the font on the current page, the effect will not be visible
before the diversion has completely been printed (except for input
protected with `\!' or `\?') since the data in the diversion is already
formatted. In most cases, this is not the expected behaviour.

File: groff, Node: Diversion Traps, Next: Input Line Traps, Prev: Page Location Traps, Up: Traps
5.24.2 Diversion Traps
----------------------
-- Request: .dt [dist macro]
Set a trap _within_ a diversion. DIST is the location of the trap
(identical to the `wh' request; default scaling indicator is `v')
and MACRO is the name of the macro to be invoked. If called
without arguments, the diversion trap is removed.
Note that there exists only a single diversion trap.
The number register `.t' still works within diversions. *Note
Diversions::, for more information.

File: groff, Node: Input Line Traps, Next: Blank Line Traps, Prev: Diversion Traps, Up: Traps
5.24.3 Input Line Traps
-----------------------
-- Request: .it n macro
-- Request: .itc n macro
Set an input line trap. N is the number of lines of input which
may be read before springing the trap, MACRO is the macro to be
invoked. Request lines are not counted as input lines.
For example, one possible use is to have a macro which prints the
next N lines in a bold font.
.de B
. it \\$1 B-end
. ft B
..
.
.de B-end
. ft R
..
The `itc' request is identical except that an interrupted text
line (ending with `\c') is not counted as a separate line.
Both requests are associated with the current environment (*note
Environments::); switching to another environment disables the
current input trap, and going back reactivates it, restoring the
number of already processed lines.

File: groff, Node: Blank Line Traps, Next: End-of-input Traps, Prev: Input Line Traps, Up: Traps
5.24.4 Blank Line Traps
-----------------------
-- Request: .blm macro
Set a blank line trap. `gtroff' executes MACRO when it encounters
a blank line in the input file.

File: groff, Node: End-of-input Traps, Prev: Blank Line Traps, Up: Traps
5.24.5 End-of-input Traps
-------------------------
-- Request: .em macro
Set a trap at the end of input. MACRO is executed after the last
line of the input file has been processed.
For example, if the document had to have a section at the bottom
of the last page for someone to approve it, the `em' request could
be used.
.de approval
. ne 5v
. sp |(\\n[.t] - 6v)
. in +4i
. lc _
. br
Approved:\t\a
. sp
Date:\t\t\a
..
.
.em approval

File: groff, Node: Diversions, Next: Environments, Prev: Traps, Up: gtroff Reference
5.25 Diversions
===============
In `gtroff' it is possible to "divert" text into a named storage area.
Due to the similarity to defining macros it is sometimes said to be
stored in a macro. This is used for saving text for output at a later
time, which is useful for keeping blocks of text on the same page,
footnotes, tables of contents, and indices.
For orthogonality it is said that `gtroff' is in the "top-level
diversion" if no diversion is active (i.e., the data is diverted to the
output device).
-- Request: .di macro
-- Request: .da macro
Begin a diversion. Like the `de' request, it takes an argument of
a macro name to divert subsequent text into. The `da' macro
appends to an existing diversion.
`di' or `da' without an argument ends the diversion.
-- Request: .box macro
-- Request: .boxa macro
Begin (or appends to) a diversion like the `di' and `da' requests.
The difference is that `box' and `boxa' do not include a
partially-filled line in the diversion.
Compare this:
Before the box.
.box xxx
In the box.
.br
.box
After the box.
.br
=> Before the box. After the box.
.xxx
=> In the box.
with this:
Before the diversion.
.di yyy
In the diversion.
.br
.di
After the diversion.
.br
=> After the diversion.
.yyy
=> Before the diversion. In the diversion.
`box' or `boxa' without an argument ends the diversion.
-- Register: \n[.z]
-- Register: \n[.d]
Diversions may be nested. The read-only number register `.z'
contains the name of the current diversion (this is a string-valued
register). The read-only number register `.d' contains the current
vertical place in the diversion. If not in a diversion it is the
same as register `nl'.
-- Register: \n[.h]
The "high-water mark" on the current page. It corresponds to the
text baseline of the lowest line on the page. This is a read-only
register.
.tm .h==\n[.h], nl==\n[nl]
=> .h==0, nl==-1
This is a test.
.br
.sp 2
.tm .h==\n[.h], nl==\n[nl]
=> .h==40, nl==120
As can be seen in the previous example, empty lines are not
considered in the return value of the `.h' register.
-- Register: \n[dn]
-- Register: \n[dl]
After completing a diversion, the read-write number registers `dn'
and `dl' contain the vertical and horizontal size of the diversion.
Note that only the just processed lines are counted: For the
computation of `dn' and `dl', the requests `da' and `boxa' are
handled as if `di' and `box' had been used - lines which have been
already stored in a macro are not taken into account.
.\" Center text both horizontally & vertically
.
.\" Enclose macro definitions in .eo and .ec
.\" to avoid the doubling of the backslash
.eo
.\" macro .(c starts centering mode
.de (c
. br
. ev (c
. evc 0
. in 0
. nf
. di @c
..
.\" macro .)c terminates centering mode
.de )c
. br
. ev
. di
. nr @s (((\n[.t]u - \n[dn]u) / 2u) - 1v)
. sp \n[@s]u
. ce 1000
. @c
. ce 0
. sp \n[@s]u
. br
. fi
. rr @s
. rm @s
. rm @c
..
.\" End of macro definitions, restore escape mechanism
.ec
-- Escape: \!
-- Escape: \?anything\?
Prevent requests, macros, and escapes from being interpreted when
read into a diversion. Both escapes take the given text and
"transparently" embed it into the diversion. This is useful for
macros which shouldn't be invoked until the diverted text is
actually output.
The `\!' escape transparently embeds text up to and including the
end of the line. The `\?' escape transparently embeds text until
the next occurrence of the `\?' escape. Example:
\?ANYTHING\?
ANYTHING may not contain newlines; use `\!' to embed newlines in
a diversion. The escape sequence `\?' is also recognized in copy
mode and turned into a single internal code; it is this code that
terminates ANYTHING. Thus the following example prints 4.
.nr x 1
.nf
.di d
\?\\?\\\\?\\\\\\\\nx\\\\?\\?\?
.di
.nr x 2
.di e
.d
.di
.nr x 3
.di f
.e
.di
.nr x 4
.f
Both escapes read the data in copy mode.
If `\!' is used in the top-level diversion, its argument is
directly embedded into the `gtroff' intermediate output. This can
be used for example to control a postprocessor which processes the
data before it is sent to the device driver.
The `\?' escape used in the top-level diversion produces no output
at all; its argument is simply ignored.
-- Request: .output string
Emit STRING directly to the `gtroff' intermediate output (subject
to copy-mode interpretation); this is similar to `\!' used at the
top level. An initial double quote in STRING is stripped off to
allow initial blanks.
This request can't be used before the first page has started - if
you get an error, simply insert `.br' before the `output' request.
Without argument, `output' is ignored.
Use with caution! It is normally only needed for mark-up used by a
postprocessor which does something with the output before sending
it to the output device, filtering out STRING again.
-- Request: .asciify div
"Unformat" the diversion specified by DIV in such a way that ASCII
characters, characters translated with the `trin' request, space
characters, and some escape sequences that were formatted and
diverted are treated like ordinary input characters when the
diversion is reread. It can be also used for gross hacks; for
example, the following sets register `n' to 1.
.tr @.
.di x
@nr n 1
.br
.di
.tr @@
.asciify x
.x
*Note Copy-in Mode::.
-- Request: .unformat div
Like `asciify', unformat the specified diversion. However,
`unformat' only unformats spaces and tabs between words.
Unformatted tabs are treated as input tokens, and spaces are
stretchable again.
The vertical size of lines is not preserved; glyph information
(font, font size, space width, etc.) is retained.

File: groff, Node: Environments, Next: Suppressing output, Prev: Diversions, Up: gtroff Reference
5.26 Environments
=================
It happens frequently that some text should be printed in a certain
format regardless of what may be in effect at the time, for example, in
a trap invoked macro to print headers and footers. To solve this
`gtroff' processes text in "environments". An environment contains
most of the parameters that control text processing. It is possible to
switch amongst these environments; by default `gtroff' processes text
in environment 0. The following is the information kept in an
environment.
* font parameters (size, family, style, glyph height and slant, space
and sentence space size)
* page parameters (line length, title length, vertical spacing, line
spacing, indentation, line numbering, centering, right-justifying,
underlining, hyphenation data)
* fill and adjust mode
* tab stops, tab and leader characters, escape character, no-break
and hyphen indicators, margin character data
* partially collected lines
* input traps
* drawing and fill colours
These environments may be given arbitrary names (see *Note
Identifiers::, for more info). Old versions of `troff' only had
environments named `0', `1', and `2'.
-- Request: .ev [env]
-- Register: \n[.ev]
Switch to another environment. The argument ENV is the name of
the environment to switch to. With no argument, `gtroff' switches
back to the previous environment. There is no limit on the number
of named environments; they are created the first time that they
are referenced. The `.ev' read-only register contains the name or
number of the current environment. This is a string-valued
register.
Note that a call to `ev' (with argument) pushes the previously
active environment onto a stack. If, say, environments `foo',
`bar', and `zap' are called (in that order), the first `ev'
request without parameter switches back to environment `bar'
(which is popped off the stack), and a second call switches back
to environment `foo'.
Here is an example:
.ev footnote-env
.fam N
.ps 6
.vs 8
.ll -.5i
.ev
...
.ev footnote-env
\(dg Note the large, friendly letters.
.ev
-- Request: .evc env
Copy the environment ENV into the current environment.
The following environment data is not copied:
* Partially filled lines.
* The status whether the previous line was interrupted.
* The number of lines still to center, or to right-justify, or
to underline (with or without underlined spaces); they are
set to zero.
* The status whether a temporary indentation is active.
* Input traps and its associated data.
* Line numbering mode is disabled; it can be reactivated with
`.nm +0'.
* The number of consecutive hyphenated lines (set to zero).
-- Register: \n[.w]
-- Register: \n[.cht]
-- Register: \n[.cdp]
-- Register: \n[.csk]
The `\n[.w]' register contains the width of the last glyph added
to the current environment.
The `\n[.cht]' register contains the height of the last glyph
added to the current environment.
The `\n[.cdp]' register contains the depth of the last glyph added
to the current environment. It is positive for glyphs extending
below the baseline.
The `\n[.csk]' register contains the "skew" (how far to the right
of the glyph's center that `gtroff' should place an accent) of the
last glyph added to the current environment.
-- Register: \n[.n]
The `\n[.n]' register contains the length of the previous output
line in the current environment.

File: groff, Node: Suppressing output, Next: Colors, Prev: Environments, Up: gtroff Reference
5.27 Suppressing output
=======================
-- Escape: \Onum
Disable or enable output depending on the value of NUM:
`\O0'
Disable any glyphs from being emitted to the device driver,
provided that the escape occurs at the outer level (see
`\O[3]' and `\O[4]'). Motion is not suppressed so
effectively `\O[0]' means _pen up_.
`\O1'
Enable output of glyphs, provided that the escape occurs at
the outer level.
`\O0' and `\O1' also reset the four registers `opminx', `opminy',
`opmaxx', and `opmaxy' to -1. *Note Register Index::. These four
registers mark the top left and bottom right hand corners of a box
which encompasses all written glyphs.
For example the input text:
Hello \O[0]world \O[1]this is a test.
produces the following output:
Hello this is a test.
`\O2'
Provided that the escape occurs at the outer level, enable
output of glyphs and also write out to `stderr' the page
number and four registers encompassing the glyphs previously
written since the last call to `\O'.
`\O3'
Begin a nesting level. At start-up, `gtroff' is at outer
level.
`\O4'
End a nesting level.
`\O[5PFILENAME]'
This escape is `grohtml' specific. Provided that this escape
occurs at the outer nesting level write the `filename' to
`stderr'. The position of the image, P, must be specified
and must be one of `l', `r', `c', or `i' (left, right,
centered, inline). FILENAME will be associated with the
production of the next inline image.

File: groff, Node: Colors, Next: I/O, Prev: Suppressing output, Up: gtroff Reference
5.28 Colors
===========
-- Request: .color [n]
-- Register: \n[.color]
If N is missing or non-zero, activate colors (this is the default);
otherwise, turn it off.
The read-only number register `.color' is 1 if colors are active,
0 otherwise.
Internally, `color' sets a global flag; it does not produce a
token. Similar to the `cp' request, you should use it at the
beginning of your document to control color output.
Colors can be also turned off with the `-c' command line option.
-- Request: .defcolor ident scheme color_components
Define color with name IDENT. SCHEME can be one of the following
values: `rgb' (three components), `cmy' (three components), `cmyk'
(four components), and `gray' or `grey' (one component).
Color components can be given either as a hexadecimal string or as
positive decimal integers in the range 0-65535. A hexadecimal
string contains all color components concatenated. It must start
with either `#' or `##'; the former specifies hex values in the
range 0-255 (which are internally multiplied by 257), the latter
in the range 0-65535. Examples: `#FFC0CB' (pink), `##ffff0000ffff'
(magenta). The default color name value is device-specific
(usually black). It is possible that the default color for `\m'
and `\M' is not identical.
A new scaling indicator `f' has been introduced which multiplies
its value by 65536; this makes it convenient to specify color
components as fractions in the range 0 to 1 (1f equals 65536u).
Example:
.defcolor darkgreen rgb 0.1f 0.5f 0.2f
Note that `f' is the default scaling indicator for the `defcolor'
request, thus the above statement is equivalent to
.defcolor darkgreen rgb 0.1 0.5 0.2
-- Request: .gcolor [color]
-- Escape: \mc
-- Escape: \m(co
-- Escape: \m[color]
-- Register: \n[.m]
Set (glyph) drawing color. The following examples show how to
turn the next four words red.
.gcolor red
these are in red
.gcolor
and these words are in black.
\m[red]these are in red\m[] and these words are in black.
The escape `\m[]' returns to the previous color, as does a call to
`gcolor' without an argument.
The name of the current drawing color is available in the
read-only, string-valued number register `.m'.
The drawing color is associated with the current environment
(*note Environments::).
Note that `\m' doesn't produce an input token in `gtroff'. As a
consequence, it can be used in requests like `mc' (which expects a
single character as an argument) to change the color on the fly:
.mc \m[red]x\m[]
-- Request: .fcolor [color]
-- Escape: \Mc
-- Escape: \M(co
-- Escape: \M[color]
-- Register: \n[.M]
Set fill (background) color for filled objects drawn with the
`\D'...'' commands.
A red ellipse can be created with the following code:
\M[red]\h'0.5i'\D'E 2i 1i'\M[]
The escape `\M[]' returns to the previous fill color, as does a
call to `fcolor' without an argument.
The name of the current fill (background) color is available in the
read-only, string-valued number register `.M'.
The fill color is associated with the current environment (*note
Environments::).
Note that `\M' doesn't produce an input token in `gtroff'.

File: groff, Node: I/O, Next: Postprocessor Access, Prev: Colors, Up: gtroff Reference
5.29 I/O
========
`gtroff' has several requests for including files:
-- Request: .so file
Read in the specified FILE and includes it in place of the `so'
request. This is quite useful for large documents, e.g. keeping
each chapter in a separate file. *Note gsoelim::, for more
information.
Since `gtroff' replaces the `so' request with the contents of
`file', it makes a difference whether the data is terminated with
a newline or not: Assuming that file `xxx' contains the word `foo'
without a final newline, this
This is
.so xxx
bar
yields `This is foobar'.
The search path for FILE can be controlled with the `-I' command
line option.
-- Request: .pso command
Read the standard output from the specified COMMAND and includes
it in place of the `pso' request.
This request causes an error if used in safer mode (which is the
default). Use `groff''s or `troff''s `-U' option to activate
unsafe mode.
The comment regarding a final newline for the `so' request is valid
for `pso' also.
-- Request: .mso file
Identical to the `so' request except that `gtroff' searches for
the specified FILE in the same directories as macro files for the
the `-m' command line option. If the file name to be included has
the form `NAME.tmac' and it isn't found, `mso' tries to include
`tmac.NAME' and vice versa.
-- Request: .trf file
-- Request: .cf file
Transparently output the contents of FILE. Each line is output as
if it were preceded by `\!'; however, the lines are not subject to
copy mode interpretation. If the file does not end with a newline,
then a newline is added (`trf' only). For example, to define a
macro `x' containing the contents of file `f', use
.di x
.trf f
.di
Both `trf' and `cf', when used in a diversion, embeds an object in
the diversion which, when reread, causes the contents of FILE to
be transparently copied through to the output. In UNIX `troff',
the contents of FILE is immediately copied through to the output
regardless of whether there is a current diversion; this behaviour
is so anomalous that it must be considered a bug.
While `cf' copies the contents of FILE completely unprocessed,
`trf' disallows characters such as NUL that are not valid `gtroff'
input characters (*note Identifiers::).
Both requests cause a line break.
-- Request: .nx [file]
Force `gtroff' to continue processing of the file specified as an
argument. If no argument is given, immediately jump to the end of
file.
-- Request: .rd [prompt [arg1 arg2 ...]]
Read from standard input, and include what is read as though it
were part of the input file. Text is read until a blank line is
encountered.
If standard input is a TTY input device (keyboard), write PROMPT
to standard error, followed by a colon (or send BEL for a beep if
no argument is given).
Arguments after PROMPT are available for the input. For example,
the line
.rd data foo bar
with the input `This is \$2.' prints
This is bar.
Using the `nx' and `rd' requests, it is easy to set up form letters.
The form letter template is constructed like this, putting the
following lines into a file called `repeat.let':
.ce
\*(td
.sp 2
.nf
.rd
.sp
.rd
.fi
Body of letter.
.bp
.nx repeat.let
When this is run, a file containing the following lines should be
redirected in. Note that requests included in this file are executed
as though they were part of the form letter. The last block of input
is the `ex' request which tells `groff' to stop processing. If this
was not there, `groff' would not know when to stop.
Trent A. Fisher
708 NW 19th Av., #202
Portland, OR 97209
Dear Trent,
Len Adollar
4315 Sierra Vista
San Diego, CA 92103
Dear Mr. Adollar,
.ex
-- Request: .pi pipe
Pipe the output of `gtroff' to the shell command(s) specified by
PIPE. This request must occur before `gtroff' has a chance to
print anything.
`pi' causes an error if used in safer mode (which is the default).
Use `groff''s or `troff''s `-U' option to activate unsafe mode.
Multiple calls to `pi' are allowed, acting as a chain. For
example,
.pi foo
.pi bar
...
is the same as `.pi foo | bar'.
Note that the intermediate output format of `gtroff' is piped to
the specified commands. Consequently, calling `groff' without the
`-Z' option normally causes a fatal error.
-- Request: .sy cmds
-- Register: \n[systat]
Execute the shell command(s) specified by CMDS. The output is not
saved anyplace, so it is up to the user to do so.
This request causes an error if used in safer mode (which is the
default). Use `groff''s or `troff''s `-U' option to activate
unsafe mode.
For example, the following code fragment introduces the current
time into a document:
.sy perl -e 'printf ".nr H %d\\n.nr M %d\\n.nr S %d\\n",\
(localtime(time))[2,1,0]' > /tmp/x\n[$$]
.so /tmp/x\n[$$]
.sy rm /tmp/x\n[$$]
\nH:\nM:\nS
Note that this works by having the `perl' script (run by `sy')
print out the `nr' requests which set the number registers `H',
`M', and `S', and then reads those commands in with the `so'
request.
For most practical purposes, the number registers `seconds',
`minutes', and `hours' which are initialized at start-up of
`gtroff' should be sufficient. Use the `af' request to get a
formatted output:
.af hours 00
.af minutes 00
.af seconds 00
\n[hours]:\n[minutes]:\n[seconds]
The `systat' read-write number register contains the return value
of the `system()' function executed by the last `sy' request.
-- Request: .open stream file
-- Request: .opena stream file
Open the specified FILE for writing and associates the specified
STREAM with it.
The `opena' request is like `open', but if the file exists, append
to it instead of truncating it.
Both `open' and `opena' cause an error if used in safer mode
(which is the default). Use `groff''s or `troff''s `-U' option to
activate unsafe mode.
-- Request: .write stream data
-- Request: .writec stream data
Write to the file associated with the specified STREAM. The
stream must previously have been the subject of an open request.
The remainder of the line is interpreted as the `ds' request reads
its second argument: A leading `"' is stripped, and it is read in
copy-in mode.
The `writec' request is like `write', but only `write' appends a
newline to the data.
-- Request: .writem stream xx
Write the contents of the macro or string XX to the file
associated with the specified STREAM.
XX is read in copy mode, i.e., already formatted elements are
ignored. Consequently, diversions must be unformatted with the
`asciify' request before calling `writem'. Usually, this means a
loss of information.
-- Request: .close stream
Close the specified STREAM; the stream is no longer an acceptable
argument to the `write' request.
Here a simple macro to write an index entry.
.open idx test.idx
.
.de IX
. write idx \\n[%] \\$*
..
.
.IX test entry
.
.close idx
-- Escape: \Ve
-- Escape: \V(ev
-- Escape: \V[env]
Interpolate the contents of the specified environment variable ENV
(one-character name E, two-character name EV) as returned by the
function `getenv'. `\V' is interpreted in copy-in mode.

File: groff, Node: Postprocessor Access, Next: Miscellaneous, Prev: I/O, Up: gtroff Reference
5.30 Postprocessor Access
=========================
There are two escapes which give information directly to the
postprocessor. This is particularly useful for embedding POSTSCRIPT
into the final document.
-- Escape: \X'xxx'
Embeds its argument into the `gtroff' output preceded with `x X'.
The escapes `\&', `\)', `\%', and `\:' are ignored within `\X',
`\ ' and `\~' are converted to single space characters. All other
escapes (except `\\' which produces a backslash) cause an error.
If the `use_charnames_in_special' keyword is set in the `DESC'
file, special characters no longer cause an error; the name XX is
represented as `\(XX)' in the `x X' output command. Additionally,
the backslash is represented as `\\'.
`use_charnames_in_special' is currently used by `grohtml' only.
-- Escape: \Yn
-- Escape: \Y(nm
-- Escape: \Y[name]
This is approximately equivalent to `\X'\*[NAME]'' (one-character
name N, two-character name NM). However, the contents of the
string or macro NAME are not interpreted; also it is permitted for
NAME to have been defined as a macro and thus contain newlines (it
is not permitted for the argument to `\X' to contain newlines).
The inclusion of newlines requires an extension to the UNIX `troff'
output format, and confuses drivers that do not know about this
extension (*note Device Control Commands::).
*Note Output Devices::.

File: groff, Node: Miscellaneous, Next: Gtroff Internals, Prev: Postprocessor Access, Up: gtroff Reference
5.31 Miscellaneous
==================
This section documents parts of `gtroff' which cannot (yet) be
categorized elsewhere in this manual.
-- Request: .nm [start [inc [space [indent]]]]
Print line numbers. START is the line number of the _next_ output
line. INC indicates which line numbers are printed. For example,
the value 5 means to emit only line numbers which are multiples
of 5; this defaults to 1. SPACE is the space to be left between
the number and the text; this defaults to one digit space. The
fourth argument is the indentation of the line numbers, defaulting
to zero. Both SPACE and INDENT are given as multiples of digit
spaces; they can be negative also. Without any arguments, line
numbers are turned off.
`gtroff' reserves three digit spaces for the line number (which is
printed right-justified) plus the amount given by INDENT; the
output lines are concatenated to the line numbers, separated by
SPACE, and _without_ reducing the line length. Depending on the
value of the horizontal page offset (as set with the `po'
request), line numbers which are longer than the reserved space
stick out to the left, or the whole line is moved to the right.
Parameters corresponding to missing arguments are not changed; any
non-digit argument (to be more precise, any argument starting with
a character valid as a delimiter for identifiers) is also treated
as missing.
If line numbering has been disabled with a call to `nm' without an
argument, it can be reactivated with `.nm +0', using the
previously active line numbering parameters.
The parameters of `nm' are associated with the current environment
(*note Environments::). The current output line number is
available in the number register `ln'.
.po 1m
.ll 2i
This test shows how line numbering works with groff.
.nm 999
This test shows how line numbering works with groff.
.br
.nm xxx 3 2
.ll -\w'0'u
This test shows how line numbering works with groff.
.nn 2
This test shows how line numbering works with groff.
And here the result:
This test shows how
line numbering works
999 with groff. This
1000 test shows how line
1001 numbering works with
1002 groff.
This test shows how
line numbering
works with groff.
This test shows how
1005 line numbering
works with groff.
-- Request: .nn [skip]
Temporarily turn off line numbering. The argument is the number
of lines not to be numbered; this defaults to 1.
-- Request: .mc glyph [dist]
Print a "margin character" to the right of the text.(1) (*note
Miscellaneous-Footnote-1::) The first argument is the glyph to be
printed. The second argument is the distance away from the right
margin. If missing, the previously set value is used; default is
10pt). For text lines that are too long (that is, longer than the
text length plus DIST), the margin character is directly appended
to the lines.
With no arguments the margin character is turned off. If this
occurs before a break, no margin character is printed.
For compatibility with AT&T `troff', a call to `mc' to set the
margin character can't be undone immediately; at least one line
gets a margin character. Thus
.ll 1i
.mc \[br]
.mc
xxx
.br
xxx
produces
xxx |
xxx
For empty lines and lines produced by the `tl' request no margin
character is emitted.
The margin character is associated with the current environment
(*note Environments::).
This is quite useful for indicating text that has changed, and, in
fact, there are programs available for doing this (they are called
`nrchbar' and `changebar' and can be found in any
`comp.sources.unix' archive).
.ll 3i
.mc |
This paragraph is highlighted with a margin
character.
.sp
Note that vertical space isn't marked.
.br
\&
.br
But we can fake it with `\&'.
Result:
This paragraph is highlighted |
with a margin character. |
Note that vertical space isn't |
marked. |
|
But we can fake it with `\&'. |
-- Request: .psbb filename
-- Register: \n[llx]
-- Register: \n[lly]
-- Register: \n[urx]
-- Register: \n[ury]
Retrieve the bounding box of the PostScript image found in
FILENAME. The file must conform to Adobe's "Document Structuring
Conventions" (DSC); the command searches for a `%%BoundingBox'
comment and extracts the bounding box values into the number
registers `llx', `lly', `urx', and `ury'. If an error occurs (for
example, `psbb' cannot find the `%%BoundingBox' comment), it sets
the four number registers to zero.
The search path for FILENAME can be controlled with the `-I'
command line option.

File: groff, Node: Miscellaneous-Footnotes, Up: Miscellaneous
(1) "Margin character" is a misnomer since it is an output glyph.

File: groff, Node: Gtroff Internals, Next: Debugging, Prev: Miscellaneous, Up: gtroff Reference
5.32 `gtroff' Internals
=======================
`gtroff' processes input in three steps. One or more input characters
are converted to an "input token".(1) (*note Gtroff
Internals-Footnote-1::) Then, one or more input tokens are converted
to an "output node". Finally, output nodes are converted to the
intermediate output language understood by all output devices.
Actually, before step one happens, `gtroff' converts certain escape
sequences into reserved input characters (not accessible by the user);
such reserved characters are used for other internal processing also -
this is the very reason why not all characters are valid input. *Note
Identifiers::, for more on this topic.
For example, the input string `fi\[:u]' is converted into a
character token `f', a character token `i', and a special token `:u'
(representing u umlaut). Later on, the character tokens `f' and `i'
are merged to a single output node representing the ligature glyph `fi'
(provided the current font has a glyph for this ligature); the same
happens with `:u'. All output glyph nodes are `processed' which means
that they are invariably associated with a given font, font size,
advance width, etc. During the formatting process, `gtroff' itself
adds various nodes to control the data flow.
Macros, diversions, and strings collect elements in two chained
lists: a list of input tokens which have been passed unprocessed, and a
list of output nodes. Consider the following the diversion.
.di xxx
a
\!b
c
.br
.di
It contains these elements.
node list token list element number
line start node -- 1
glyph node `a' -- 2
word space node -- 3
-- `b' 4
-- `\n' 5
glyph node `c' -- 6
vertical size node -- 7
vertical size node -- 8
-- `\n' 9
Elements 1, 7, and 8 are inserted by `gtroff'; the latter two (which
are always present) specify the vertical extent of the last line,
possibly modified by `\x'. The `br' request finishes the current
partial line, inserting a newline input token which is subsequently
converted to a space when the diversion is reread. Note that the word
space node has a fixed width which isn't stretchable anymore. To
convert horizontal space nodes back to input tokens, use the `unformat'
request.
Macros only contain elements in the token list (and the node list is
empty); diversions and strings can contain elements in both lists.
Note that the `chop' request simply reduces the number of elements
in a macro, string, or diversion by one. Exceptions are "compatibility
save" and "compatibility ignore" input tokens which are ignored. The
`substring' request also ignores those input tokens.
Some requests like `tr' or `cflags' work on glyph identifiers only;
this means that the associated glyph can be changed without destroying
this association. This can be very helpful for substituting glyphs.
In the following example, we assume that glyph `foo' isn't available by
default, so we provide a substitution using the `fchar' request and map
it to input character `x'.
.fchar \[foo] foo
.tr x \[foo]
Now let us assume that we install an additional special font `bar'
which has glyph `foo'.
.special bar
.rchar \[foo]
Since glyphs defined with `fchar' are searched before glyphs in special
fonts, we must call `rchar' to remove the definition of the fallback
glyph. Anyway, the translation is still active; `x' now maps to the
real glyph `foo'.
Macro and request arguments preserve the compatibility mode:
.cp 1 \" switch to compatibility mode
.de xx
\\$1
..
.cp 0 \" switch compatibility mode off
.xx caf\['e]
=> caf<61>
Since compatibility mode is on while `de' is called, the macro `xx'
activates compatibility mode while executing. Argument `$1' can still
be handled properly because it inherits the compatibility mode status
which was active at the point where `xx' is called.
After expansion of the parameters, the compatibility save and restore
tokens are removed.

File: groff, Node: Gtroff Internals-Footnotes, Up: Gtroff Internals
(1) Except the escapes `\f', `\F', `\H', `\m', `\M', `\R', `\s', and
`\S' which are processed immediately if not in copy-in mode.

File: groff, Node: Debugging, Next: Implementation Differences, Prev: Gtroff Internals, Up: gtroff Reference
5.33 Debugging
==============
`gtroff' is not easy to debug, but there are some useful features and
strategies for debugging.
-- Request: .lf line [filename]
Change the line number and optionally the file name `gtroff' shall
use for error and warning messages. LINE is the input line number
of the _next_ line.
Without argument, the request is ignored.
This is a debugging aid for documents which are split into many
files, then put together with `soelim' and other preprocessors.
Usually, it isn't invoked manually.
Note that other `troff' implementations (including the original
AT&T version) handle `lf' differently. For them, LINE changes the
line number of the _current_ line.
-- Request: .tm string
-- Request: .tm1 string
-- Request: .tmc string
Send STRING to the standard error output; this is very useful for
printing debugging messages among other things.
STRING is read in copy mode.
The `tm' request ignores leading spaces of STRING; `tm1' handles
its argument similar to the `ds' request: a leading double quote
in STRING is stripped to allow initial blanks.
The `tmc' request is similar to `tm1' but does not append a
newline (as is done in `tm' and `tm1').
-- Request: .ab [string]
Similar to the `tm' request, except that it causes `gtroff' to
stop processing. With no argument it prints `User Abort.' to
standard error.
-- Request: .ex
The `ex' request also causes `gtroff' to stop processing; see also
*Note I/O::.
When doing something involved it is useful to leave the debugging
statements in the code and have them turned on by a command line flag.
.if \n(DB .tm debugging output
To activate these statements say
groff -rDB=1 file
If it is known in advance that there will be many errors and no
useful output, `gtroff' can be forced to suppress formatted output with
the `-z' flag.
-- Request: .pm
Print the entire symbol table on `stderr'. Names of all defined
macros, strings, and diversions are print together with their size
in bytes. Since `gtroff' sometimes adds nodes by itself, the
returned size can be larger than expected.
This request differs from UNIX `troff': `gtroff' reports the sizes
of diversions, ignores an additional argument to print only the
total of the sizes, and the size isn't returned in blocks of 128
characters.
-- Request: .pnr
Print the names and contents of all currently defined number
registers on `stderr'.
-- Request: .ptr
Print the names and positions of all traps (not including input
line traps and diversion traps) on `stderr'. Empty slots in the
page trap list are printed as well, because they can affect the
priority of subsequently planted traps.
-- Request: .fl
Instruct `gtroff' to flush its output immediately. The intent is
for interactive use, but this behaviour is currently not
implemented in `gtroff'. Contrary to UNIX `troff', TTY output is
sent to a device driver also (`grotty'), making it non-trivial to
communicate interactively.
This request causes a line break.
-- Request: .backtrace
Print a backtrace of the input stack to the standard error stream.
Consider the following in file `test':
.de xxx
. backtrace
..
.de yyy
. xxx
..
.
.yyy
On execution, `gtroff' prints the following:
test:2: backtrace: macro `xxx'
test:5: backtrace: macro `yyy'
test:8: backtrace: file `test'
The option `-b' of `gtroff' internally calls a variant of this
request on each error and warning.
-- Register: \n[slimit]
Use the `slimit' number register to set the maximum number of
objects on the input stack. If `slimit' is less than or equal
to 0, there is no limit set. With no limit, a buggy recursive
macro can exhaust virtual memory.
The default value is 1000; this is a compile-time constant.
-- Request: .warnscale si
Set the scaling indicator used in warnings to SI. Valid values for
SI are `u', `i', `c', `p', and `P'. At startup, it is set to `i'.
-- Request: .spreadwarn [limit]
Make `gtroff' emit a warning if the additional space inserted for
each space between words in an output line is larger or equal to
LIMIT. A negative value is changed to zero; no argument toggles
the warning on and off without changing LIMIT. The default scaling
indicator is `m'. At startup, `spreadwarn' is deactivated, and
LIMIT is set to 3m.
For example,
.spreadwarn 0.2m
will cause a warning if `gtroff' must add 0.2m or more for each
interword space in a line.
This request is active only if text is justified to both margins
(using `.ad b').
`gtroff' has command line options for printing out more warnings
(`-w') and for printing backtraces (`-b') when a warning or an error
occurs. The most verbose level of warnings is `-ww'.
-- Request: .warn [flags]
-- Register: \n[.warn]
Control the level of warnings checked for. The FLAGS are the sum
of the numbers associated with each warning that is to be enabled;
all other warnings are disabled. The number associated with each
warning is listed below. For example, `.warn 0' disables all
warnings, and `.warn 1' disables all warnings except that about
missing glyphs. If no argument is given, all warnings are enabled.
The read-only number register `.warn' contains the current warning
level.
* Menu:
* Warnings::

File: groff, Node: Warnings, Prev: Debugging, Up: Debugging
5.33.1 Warnings
---------------
The warnings that can be given to `gtroff' are divided into the
following categories. The name associated with each warning is used by
the `-w' and `-W' options; the number is used by the `warn' request and
by the `.warn' register.
`char'
`1'
Non-existent glyphs.(1) (*note Warnings-Footnote-1::) This is
enabled by default.
`number'
`2'
Invalid numeric expressions. This is enabled by default. *Note
Expressions::.
`break'
`4'
In fill mode, lines which could not be broken so that their length
was less than the line length. This is enabled by default.
`delim'
`8'
Missing or mismatched closing delimiters.
`el'
`16'
Use of the `el' request with no matching `ie' request. *Note
if-else::.
`scale'
`32'
Meaningless scaling indicators.
`range'
`64'
Out of range arguments.
`syntax'
`128'
Dubious syntax in numeric expressions.
`di'
`256'
Use of `di' or `da' without an argument when there is no current
diversion.
`mac'
`512'
Use of undefined strings, macros and diversions. When an undefined
string, macro, or diversion is used, that string is automatically
defined as empty. So, in most cases, at most one warning is given
for each name.
`reg'
`1024'
Use of undefined number registers. When an undefined number
register is used, that register is automatically defined to have a
value of 0. So, in most cases, at most one warning is given for
use of a particular name.
`tab'
`2048'
Use of a tab character where a number was expected.
`right-brace'
`4096'
Use of `\}' where a number was expected.
`missing'
`8192'
Requests that are missing non-optional arguments.
`input'
`16384'
Invalid input characters.
`escape'
`32768'
Unrecognized escape sequences. When an unrecognized escape
sequence `\X' is encountered, the escape character is ignored, and
X is printed.
`space'
`65536'
Missing space between a request or macro and its argument. This
warning is given when an undefined name longer than two characters
is encountered, and the first two characters of the name make a
defined name. The request or macro is not invoked. When this
warning is given, no macro is automatically defined. This is
enabled by default. This warning never occurs in compatibility
mode.
`font'
`131072'
Non-existent fonts. This is enabled by default.
`ig'
`262144'
Invalid escapes in text ignored with the `ig' request. These are
conditions that are errors when they do not occur in ignored text.
`color'
`524288'
Color related warnings.
`all'
All warnings except `di', `mac' and `reg'. It is intended that
this covers all warnings that are useful with traditional macro
packages.
`w'
All warnings.

File: groff, Node: Warnings-Footnotes, Up: Warnings
(1) `char' is a misnomer since it reports missing glyphs - there
aren't missing input characters, only invalid ones.

File: groff, Node: Implementation Differences, Prev: Debugging, Up: gtroff Reference
5.34 Implementation Differences
===============================
GNU `troff' has a number of features which cause incompatibilities with
documents written with old versions of `troff'.
Long names cause some incompatibilities. UNIX `troff' interprets
.dsabcd
as defining a string `ab' with contents `cd'. Normally, GNU `troff'
interprets this as a call of a macro named `dsabcd'. Also UNIX `troff'
interprets `\*[' or `\n[' as references to a string or number register
called `['. In GNU `troff', however, this is normally interpreted as
the start of a long name. In compatibility mode GNU `troff' interprets
long names in the traditional way (which means that they are not
recognized as names).
-- Request: .cp [n]
-- Request: .do cmd
-- Register: \n[.C]
If N is missing or non-zero, turn on compatibility mode;
otherwise, turn it off.
The read-only number register `.C' is 1 if compatibility mode is
on, 0 otherwise.
Compatibility mode can be also turned on with the `-C' command line
option.
The `do' request turns off compatibility mode while executing its
arguments as a `gtroff' command.
.do fam T
executes the `fam' request when compatibility mode is enabled.
`gtroff' restores the previous compatibility setting before
interpreting any files sourced by the CMD.
Two other features are controlled by `-C'. If not in compatibility
mode, GNU `troff' preserves the input level in delimited arguments:
.ds xx '
\w'abc\*(xxdef'
In compatibility mode, the string `72def'' is returned; without `-C'
the resulting string is `168' (assuming a TTY output device).
Finally, the escapes `\f', `\H', `\m', `\M', `\R', `\s', and `\S'
are transparent for recognizing the beginning of a line only in
compatibility mode (this is a rather obscure feature). For example,
the code
.de xx
Hallo!
..
\fB.xx\fP
prints `Hallo!' in bold face if in compatibility mode, and `.xx' in
bold face otherwise.
GNU `troff' does not allow the use of the escape sequences `\|',
`\^', `\&', `\{', `\}', `\<SP>', `\'', `\`', `\-', `\_', `\!', `\%',
and `\c' in names of strings, macros, diversions, number registers,
fonts or environments; UNIX `troff' does. The `\A' escape sequence
(*note Identifiers::) may be helpful in avoiding use of these escape
sequences in names.
Fractional point sizes cause one noteworthy incompatibility. In
UNIX `troff' the `ps' request ignores scale indicators and thus
.ps 10u
sets the point size to 10 points, whereas in GNU `troff' it sets the
point size to 10 scaled points. *Note Fractional Type Sizes::, for
more information.
In GNU `troff' there is a fundamental difference between
(unformatted) input characters and (formatted) output glyphs.
Everything that affects how a glyph is output is stored with the glyph
node; once a glyph node has been constructed it is unaffected by any
subsequent requests that are executed, including `bd', `cs', `tkf',
`tr', or `fp' requests. Normally glyphs are constructed from input
characters at the moment immediately before the glyph is added to the
current output line. Macros, diversions and strings are all, in fact,
the same type of object; they contain lists of input characters and
glyph nodes in any combination. A glyph node does not behave like an
input character for the purposes of macro processing; it does not
inherit any of the special properties that the input character from
which it was constructed might have had. For example,
.di x
\\\\
.br
.di
.x
prints `\\' in GNU `troff'; each pair of input backslashes is turned
into one output backslash and the resulting output backslashes are not
interpreted as escape characters when they are reread. UNIX `troff'
would interpret them as escape characters when they were reread and
would end up printing one `\'. The correct way to obtain a printable
backslash is to use the `\e' escape sequence: This always prints a
single instance of the current escape character, regardless of whether
or not it is used in a diversion; it also works in both GNU `troff' and
UNIX `troff'.(1) (*note Implementation Differences-Footnote-1::) To
store, for some reason, an escape sequence in a diversion that will be
interpreted when the diversion is reread, either use the traditional
`\!' transparent output facility, or, if this is unsuitable, the new
`\?' escape sequence.
*Note Diversions::, and *Note Gtroff Internals::, for more
information.

File: groff, Node: Implementation Differences-Footnotes, Up: Implementation Differences
(1) To be completely independent of the current escape character,
use `\(rs' which represents a reverse solidus (backslash) glyph.

File: groff, Node: Preprocessors, Next: Output Devices, Prev: gtroff Reference, Up: Top
6 Preprocessors
***************
This chapter describes all preprocessors that come with `groff' or
which are freely available.
* Menu:
* geqn::
* gtbl::
* gpic::
* ggrn::
* grap::
* grefer::
* gsoelim::

File: groff, Node: geqn, Next: gtbl, Prev: Preprocessors, Up: Preprocessors
6.1 `geqn'
==========
* Menu:
* Invoking geqn::

File: groff, Node: Invoking geqn, Prev: geqn, Up: geqn
6.1.1 Invoking `geqn'
---------------------

File: groff, Node: gtbl, Next: gpic, Prev: geqn, Up: Preprocessors
6.2 `gtbl'
==========
* Menu:
* Invoking gtbl::

File: groff, Node: Invoking gtbl, Prev: gtbl, Up: gtbl
6.2.1 Invoking `gtbl'
---------------------

File: groff, Node: gpic, Next: ggrn, Prev: gtbl, Up: Preprocessors
6.3 `gpic'
==========
* Menu:
* Invoking gpic::

File: groff, Node: Invoking gpic, Prev: gpic, Up: gpic
6.3.1 Invoking `gpic'
---------------------

File: groff, Node: ggrn, Next: grap, Prev: gpic, Up: Preprocessors
6.4 `ggrn'
==========
* Menu:
* Invoking ggrn::

File: groff, Node: Invoking ggrn, Prev: ggrn, Up: ggrn
6.4.1 Invoking `ggrn'
---------------------

File: groff, Node: grap, Next: grefer, Prev: ggrn, Up: Preprocessors
6.5 `grap'
==========
A free implementation of `grap', written by Ted Faber, is available as
an extra package from the following address:
`http://www.lunabase.org/~faber/Vault/software/grap/'

File: groff, Node: grefer, Next: gsoelim, Prev: grap, Up: Preprocessors
6.6 `grefer'
============
* Menu:
* Invoking grefer::

File: groff, Node: Invoking grefer, Prev: grefer, Up: grefer
6.6.1 Invoking `grefer'
-----------------------

File: groff, Node: gsoelim, Prev: grefer, Up: Preprocessors
6.7 `gsoelim'
=============
* Menu:
* Invoking gsoelim::

File: groff, Node: Invoking gsoelim, Prev: gsoelim, Up: gsoelim
6.7.1 Invoking `gsoelim'
------------------------

File: groff, Node: Output Devices, Next: File formats, Prev: Preprocessors, Up: Top
7 Output Devices
****************
* Menu:
* Special Characters::
* grotty::
* grops::
* grodvi::
* grolj4::
* grolbp::
* grohtml::
* gxditview::

File: groff, Node: Special Characters, Next: grotty, Prev: Output Devices, Up: Output Devices
7.1 Special Characters
======================
*Note Font Files::.

File: groff, Node: grotty, Next: grops, Prev: Special Characters, Up: Output Devices
7.2 `grotty'
============
* Menu:
* Invoking grotty::

File: groff, Node: Invoking grotty, Prev: grotty, Up: grotty
7.2.1 Invoking `grotty'
-----------------------

File: groff, Node: grops, Next: grodvi, Prev: grotty, Up: Output Devices
7.3 `grops'
===========
* Menu:
* Invoking grops::
* Embedding PostScript::

File: groff, Node: Invoking grops, Next: Embedding PostScript, Prev: grops, Up: grops
7.3.1 Invoking `grops'
----------------------

File: groff, Node: Embedding PostScript, Prev: Invoking grops, Up: grops
7.3.2 Embedding POSTSCRIPT
--------------------------

File: groff, Node: grodvi, Next: grolj4, Prev: grops, Up: Output Devices
7.4 `grodvi'
============
* Menu:
* Invoking grodvi::

File: groff, Node: Invoking grodvi, Prev: grodvi, Up: grodvi
7.4.1 Invoking `grodvi'
-----------------------

File: groff, Node: grolj4, Next: grolbp, Prev: grodvi, Up: Output Devices
7.5 `grolj4'
============
* Menu:
* Invoking grolj4::

File: groff, Node: Invoking grolj4, Prev: grolj4, Up: grolj4
7.5.1 Invoking `grolj4'
-----------------------

File: groff, Node: grolbp, Next: grohtml, Prev: grolj4, Up: Output Devices
7.6 `grolbp'
============
* Menu:
* Invoking grolbp::

File: groff, Node: Invoking grolbp, Prev: grolbp, Up: grolbp
7.6.1 Invoking `grolbp'
-----------------------

File: groff, Node: grohtml, Next: gxditview, Prev: grolbp, Up: Output Devices
7.7 `grohtml'
=============
* Menu:
* Invoking grohtml::
* grohtml specific registers and strings::

File: groff, Node: Invoking grohtml, Next: grohtml specific registers and strings, Prev: grohtml, Up: grohtml
7.7.1 Invoking `grohtml'
------------------------

File: groff, Node: grohtml specific registers and strings, Prev: Invoking grohtml, Up: grohtml
7.7.2 `grohtml' specific registers and strings
----------------------------------------------
-- Register: \n[ps4html]
-- String: \*[www-image-template]
The registers `ps4html' and `www-image-template' are defined by
the `pre-grohtml' preprocessor. `pre-grohtml' reads in the
`troff' input, marks up the inline equations and passes the result
firstly to
troff -Tps -rps4html=1 -dwww-image-template=TEMPLATE
and secondly to
troff -Thtml
The PostScript device is used to create all the image files, and
the register `ps4html' enables the macro sets to ignore floating
keeps, footers, and headings.
The register `www-image-template' is set to the user specified
template name or the default name.

File: groff, Node: gxditview, Prev: grohtml, Up: Output Devices
7.8 `gxditview'
===============
* Menu:
* Invoking gxditview::

File: groff, Node: Invoking gxditview, Prev: gxditview, Up: gxditview
7.8.1 Invoking `gxditview'
--------------------------

File: groff, Node: File formats, Next: Installation, Prev: Output Devices, Up: Top
8 File formats
**************
All files read and written by `gtroff' are text files. The following
two sections describe their format.
* Menu:
* gtroff Output::
* Font Files::

File: groff, Node: gtroff Output, Next: Font Files, Prev: File formats, Up: File formats
8.1 `gtroff' Output
===================
This section describes the intermediate output format of GNU `troff'.
This output is produced by a run of `gtroff' before it is fed into a
device postprocessor program.
As `groff' is a wrapper program around `gtroff' that automatically
calls a postprocessor, this output does not show up normally. This is
why it is called "intermediate". `groff' provides the option `-Z' to
inhibit postprocessing, such that the produced intermediate output is
sent to standard output just like calling `gtroff' manually.
Here, the term "troff output" describes what is output by `gtroff',
while "intermediate output" refers to the language that is accepted by
the parser that prepares this output for the postprocessors. This
parser is smarter on whitespace and implements obsolete elements for
compatibility, otherwise both formats are the same.(1) (*note gtroff
Output-Footnote-1::)
The main purpose of the intermediate output concept is to facilitate
the development of postprocessors by providing a common programming
interface for all devices. It has a language of its own that is
completely different from the `gtroff' language. While the `gtroff'
language is a high-level programming language for text processing, the
intermediate output language is a kind of low-level assembler language
by specifying all positions on the page for writing and drawing.
The intermediate output produced by `gtroff' is fairly readable,
while output from AT&T `troff' is rather hard to understand because of
strange habits that are still supported, but not used any longer by
`gtroff'.
* Menu:
* Language Concepts::
* Command Reference::
* Intermediate Output Examples::
* Output Language Compatibility::

File: groff, Node: gtroff Output-Footnotes, Up: gtroff Output
(1) The parser and postprocessor for intermediate output can be
found in the file
`GROFF-SOURCE-DIR/src/libs/libdriver/input.cpp'.

File: groff, Node: Language Concepts, Next: Command Reference, Prev: gtroff Output, Up: gtroff Output
8.1.1 Language Concepts
-----------------------
During the run of `gtroff', the input data is cracked down to the
information on what has to be printed at what position on the intended
device. So the language of the intermediate output format can be quite
small. Its only elements are commands with and without arguments. In
this section, the term "command" always refers to the intermediate
output language, and never to the `gtroff' language used for document
formatting. There are commands for positioning and text writing, for
drawing, and for device controlling.
* Menu:
* Separation::
* Argument Units::
* Document Parts::

File: groff, Node: Separation, Next: Argument Units, Prev: Language Concepts, Up: Language Concepts
8.1.1.1 Separation
..................
AT&T `troff' output has strange requirements on whitespace. The
`gtroff' output parser, however, is smart about whitespace by making it
maximally optional. The whitespace characters, i.e., the tab, space,
and newline characters, always have a syntactical meaning. They are
never printable because spacing within the output is always done by
positioning commands.
Any sequence of space or tab characters is treated as a single
"syntactical space". It separates commands and arguments, but is only
required when there would occur a clashing between the command code and
the arguments without the space. Most often, this happens when
variable-length command names, arguments, argument lists, or command
clusters meet. Commands and arguments with a known, fixed length need
not be separated by syntactical space.
A line break is a syntactical element, too. Every command argument
can be followed by whitespace, a comment, or a newline character. Thus
a "syntactical line break" is defined to consist of optional
syntactical space that is optionally followed by a comment, and a
newline character.
The normal commands, those for positioning and text, consist of a
single letter taking a fixed number of arguments. For historical
reasons, the parser allows to stack such commands on the same line, but
fortunately, in `gtroff''s intermediate output, every command with at
least one argument is followed by a line break, thus providing
excellent readability.
The other commands - those for drawing and device controlling - have
a more complicated structure; some recognize long command names, and
some take a variable number of arguments. So all `D' and `x' commands
were designed to request a syntactical line break after their last
argument. Only one command, `x X', has an argument that can stretch
over several lines; all other commands must have all of their arguments
on the same line as the command, i.e., the arguments may not be
splitted by a line break.
Empty lines (these are lines containing only space and/or a
comment), can occur everywhere. They are just ignored.

File: groff, Node: Argument Units, Next: Document Parts, Prev: Separation, Up: Language Concepts
8.1.1.2 Argument Units
......................
Some commands take integer arguments that are assumed to represent
values in a measurement unit, but the letter for the corresponding
scale indicator is not written with the output command arguments. Most
commands assume the scale indicator `u', the basic unit of the device,
some use `z', the scaled point unit of the device, while others, such
as the color commands, expect plain integers.
Note that single characters can have the eighth bit set, as can the
names of fonts and special characters. The names of characters and
fonts can be of arbitrary length. A character that is to be printed
will always be in the current font.
A string argument is always terminated by the next whitespace
character (space, tab, or newline); an embedded `#' character is
regarded as part of the argument, not as the beginning of a comment
command. An integer argument is already terminated by the next
non-digit character, which then is regarded as the first character of
the next argument or command.

File: groff, Node: Document Parts, Prev: Argument Units, Up: Language Concepts
8.1.1.3 Document Parts
......................
A correct intermediate output document consists of two parts, the
"prologue" and the "body".
The task of the prologue is to set the general device parameters
using three exactly specified commands. `gtroff''s prologue is
guaranteed to consist of the following three lines (in that order):
x T DEVICE
x res N H V
x init
with the arguments set as outlined in *Note Device Control Commands::.
Note that the parser for the intermediate output format is able to
swallow additional whitespace and comments as well even in the prologue.
The body is the main section for processing the document data.
Syntactically, it is a sequence of any commands different from the ones
used in the prologue. Processing is terminated as soon as the first
`x stop' command is encountered; the last line of any `gtroff'
intermediate output always contains such a command.
Semantically, the body is page oriented. A new page is started by a
`p' command. Positioning, writing, and drawing commands are always
done within the current page, so they cannot occur before the first `p'
command. Absolute positioning (by the `H' and `V' commands) is done
relative to the current page; all other positioning is done relative to
the current location within this page.

File: groff, Node: Command Reference, Next: Intermediate Output Examples, Prev: Language Concepts, Up: gtroff Output
8.1.2 Command Reference
-----------------------
This section describes all intermediate output commands, both from AT&T
`troff' as well as the `gtroff' extensions.
* Menu:
* Comment Command::
* Simple Commands::
* Graphics Commands::
* Device Control Commands::
* Obsolete Command::

File: groff, Node: Comment Command, Next: Simple Commands, Prev: Command Reference, Up: Command Reference
8.1.2.1 Comment Command
.......................
`#ANYTHING<end of line>'
A comment. Ignore any characters from the `#' character up to the
next newline character.
This command is the only possibility for commenting in the
intermediate output. Each comment can be preceded by arbitrary
syntactical space; every command can be terminated by a comment.

File: groff, Node: Simple Commands, Next: Graphics Commands, Prev: Comment Command, Up: Command Reference
8.1.2.2 Simple Commands
.......................
The commands in this subsection have a command code consisting of a
single character, taking a fixed number of arguments. Most of them are
commands for positioning and text writing. These commands are smart
about whitespace. Optionally, syntactical space can be inserted
before, after, and between the command letter and its arguments. All
of these commands are stackable, i.e., they can be preceded by other
simple commands or followed by arbitrary other commands on the same
line. A separating syntactical space is only necessary when two
integer arguments would clash or if the preceding argument ends with a
string argument.
`C XXX<whitespace>'
Print a special character named XXX. The trailing syntactical
space or line break is necessary to allow glyph names of arbitrary
length. The glyph is printed at the current print position; the
glyph's size is read from the font file. The print position is
not changed.
`c G'
Print glyph G at the current print position;(1) (*note Simple
Commands-Footnote-1::) the glyph's size is read from the font
file. The print position is not changed.
`f N'
Set font to font number N (a non-negative integer).
`H N'
Move right to the absolute vertical position N (a non-negative
integer in basic units `u' relative to left edge of current page.
`h N'
Move N (a non-negative integer) basic units `u' horizontally to
the right. The original UNIX troff manual allows negative values
for N also, but `gtroff' doesn't use this.
`m COLOR-SCHEME [COMPONENT ...]'
Set the color for text (glyphs), line drawing, and the outline of
graphic objects using different color schemes; the analoguous
command for the filling color of graphic objects is `DF'. The
color components are specified as integer arguments between 0 and
65536. The number of color components and their meaning vary for
the different color schemes. These commands are generated by
`gtroff''s escape sequence `\m'. No position changing. These
commands are a `gtroff' extension.
`mc CYAN MAGENTA YELLOW'
Set color using the CMY color scheme, having the 3 color
components CYAN, MAGENTA, and YELLOW.
`md'
Set color to the default color value (black in most cases).
No component arguments.
`mg GRAY'
Set color to the shade of gray given by the argument, an
integer between 0 (black) and 65536 (white).
`mk CYAN MAGENTA YELLOW BLACK'
Set color using the CMYK color scheme, having the 4 color
components CYAN, MAGENTA, YELLOW, and BLACK.
`mr RED GREEN BLUE'
Set color using the RGB color scheme, having the 3 color
components RED, GREEN, and BLUE.
`N N'
Print glyph with index N (a non-negative integer) of the current
font. This command is a `gtroff' extension.
`n B A'
Inform the device about a line break, but no positioning is done by
this command. In AT&T `troff', the integer arguments B and A
informed about the space before and after the current line to make
the intermediate output more human readable without performing any
action. In `groff', they are just ignored, but they must be
provided for compatibility reasons.
`p N'
Begin a new page in the outprint. The page number is set to N.
This page is completely independent of pages formerly processed
even if those have the same page number. The vertical position on
the outprint is automatically set to 0. All positioning, writing,
and drawing is always done relative to a page, so a `p' command
must be issued before any of these commands.
`s N'
Set point size to N scaled points (this is unit `z'). AT&T
`troff' used the unit points (`p') instead. *Note Output Language
Compatibility::.
`t XXX<whitespace>'
`t XXX DUMMY-ARG<whitespace>'
Print a word, i.e., a sequence of characters XXX representing
output glyphs which names are single characters, terminated by a
space character or a line break; an optional second integer
argument is ignored (this allows the formatter to generate an even
number of arguments). The first glyph should be printed at the
current position, the current horizontal position should then be
increased by the width of the first glyph, and so on for each
glyph. The widths of the glyphs are read from the font file,
scaled for the current point size, and rounded to a multiple of
the horizontal resolution. Special characters cannot be printed
using this command (use the `C' command for special characters).
This command is a `gtroff' extension; it is only used for devices
whose `DESC' file contains the `tcommand' keyword (*note DESC File
Format::).
`u N XXX<whitespace>'
Print word with track kerning. This is the same as the `t'
command except that after printing each glyph, the current
horizontal position is increased by the sum of the width of that
glyph and N (an integer in basic units `u'). This command is a
`gtroff' extension; it is only used for devices whose `DESC' file
contains the `tcommand' keyword (*note DESC File Format::).
`V N'
Move down to the absolute vertical position N (a non-negative
integer in basic units `u') relative to upper edge of current page.
`v N'
Move N basic units `u' down (N is a non-negative integer). The
original UNIX troff manual allows negative values for N also, but
`gtroff' doesn't use this.
`w'
Informs about a paddable white space to increase readability. The
spacing itself must be performed explicitly by a move command.

File: groff, Node: Simple Commands-Footnotes, Up: Simple Commands
(1) `c' is actually a misnomer since it outputs a glyph.

File: groff, Node: Graphics Commands, Next: Device Control Commands, Prev: Simple Commands, Up: Command Reference
8.1.2.3 Graphics Commands
.........................
Each graphics or drawing command in the intermediate output starts with
the letter `D', followed by one or two characters that specify a
subcommand; this is followed by a fixed or variable number of integer
arguments that are separated by a single space character. A `D'
command may not be followed by another command on the same line (apart
from a comment), so each `D' command is terminated by a syntactical
line break.
`gtroff' output follows the classical spacing rules (no space
between command and subcommand, all arguments are preceded by a single
space character), but the parser allows optional space between the
command letters and makes the space before the first argument optional.
As usual, each space can be any sequence of tab and space characters.
Some graphics commands can take a variable number of arguments. In
this case, they are integers representing a size measured in basic
units `u'. The arguments called H1, H2, ..., HN stand for horizontal
distances where positive means right, negative left. The arguments
called V1, V2, ..., VN stand for vertical distances where positive
means down, negative up. All these distances are offsets relative to
the current location.
Each graphics command directly corresponds to a similar `gtroff'
`\D' escape sequence. *Note Drawing Requests::.
Unknown `D' commands are assumed to be device-specific. Its
arguments are parsed as strings; the whole information is then sent to
the postprocessor.
In the following command reference, the syntax element <line
break> means a syntactical line break as defined above.
`D~ H1 V1 H2 V2 ... HN VN<line break>'
Draw B-spline from current position to offset (H1,V1), then to
offset (H2,V2), if given, etc. up to (HN,VN). This command takes
a variable number of argument pairs; the current position is moved
to the terminal point of the drawn curve.
`Da H1 V1 H2 V2<line break>'
Draw arc from current position to (H1,V1)+(H2,V2) with center at
(H1,V1); then move the current position to the final point of the
arc.
`DC D<line break>'
`DC D DUMMY-ARG<line break>'
Draw a solid circle using the current fill color with diameter D
(integer in basic units `u') with leftmost point at the current
position; then move the current position to the rightmost point of
the circle. An optional second integer argument is ignored (this
allows the formatter to generate an even number of arguments).
This command is a `gtroff' extension.
`Dc D<line break>'
Draw circle line with diameter D (integer in basic units `u') with
leftmost point at the current position; then move the current
position to the rightmost point of the circle.
`DE H V<line break>'
Draw a solid ellipse in the current fill color with a horizontal
diameter of H and a vertical diameter of V (both integers in basic
units `u') with the leftmost point at the current position; then
move to the rightmost point of the ellipse. This command is a
`gtroff' extension.
`De H V<line break>'
Draw an outlined ellipse with a horizontal diameter of H and a
vertical diameter of V (both integers in basic units `u') with the
leftmost point at current position; then move to the rightmost
point of the ellipse.
`DF COLOR-SCHEME [COMPONENT ...]<line break>'
Set fill color for solid drawing objects using different color
schemes; the analoguous command for setting the color of text, line
graphics, and the outline of graphic objects is `m'. The color
components are specified as integer arguments between 0 and 65536.
The number of color components and their meaning vary for the
different color schemes. These commands are generated by
`gtroff''s escape sequences `\D'F ...'' and `\M' (with no other
corresponding graphics commands). No position changing. This
command is a `gtroff' extension.
`DFc CYAN MAGENTA YELLOW<line break>'
Set fill color for solid drawing objects using the CMY color
scheme, having the 3 color components CYAN, MAGENTA, and
YELLOW.
`DFd<line break>'
Set fill color for solid drawing objects to the default fill
color value (black in most cases). No component arguments.
`DFg GRAY<line break>'
Set fill color for solid drawing objects to the shade of gray
given by the argument, an integer between 0 (black) and 65536
(white).
`DFk CYAN MAGENTA YELLOW BLACK<line break>'
Set fill color for solid drawing objects using the CMYK color
scheme, having the 4 color components CYAN, MAGENTA, YELLOW,
and BLACK.
`DFr RED GREEN BLUE<line break>'
Set fill color for solid drawing objects using the RGB color
scheme, having the 3 color components RED, GREEN, and BLUE.
`Df N<line break>'
The argument N must be an integer in the range -32767 to 32767.
0 <= N <= 1000
Set the color for filling solid drawing objects to a shade of
gray, where 0 corresponds to solid white, 1000 (the default)
to solid black, and values in between to intermediate shades
of gray; this is obsoleted by command `DFg'.
N < 0 or N > 1000
Set the filling color to the color that is currently being
used for the text and the outline, see command `m'. For
example, the command sequence
mg 0 0 65536
Df -1
sets all colors to blue.
No position changing. This command is a `gtroff' extension.
`Dl H V<line break>'
Draw line from current position to offset (H,V) (integers in basic
units `u'); then set current position to the end of the drawn line.
`Dp H1 V1 H2 V2 ... HN VN<line break>'
Draw a polygon line from current position to offset (H1,V1), from
there to offset (H2,V2), etc. up to offset (HN,VN), and from there
back to the starting position. For historical reasons, the
position is changed by adding the sum of all arguments with odd
index to the actual horizontal position and the even ones to the
vertical position. Although this doesn't make sense it is kept
for compatibility. This command is a `gtroff' extension.
`Dp H1 V1 H2 V2 ... HN VN<line break>'
Draw a solid polygon in the current fill color rather than an
outlined polygon, using the same arguments and positioning as the
corresponding `Dp' command. This command is a `gtroff' extension.
`Dt N<line break>'
Set the current line thickness to N (an integer in basic units
`u') if N>0; if N=0 select the smallest available line thickness;
if N<0 set the line thickness proportional to the point size (this
is the default before the first `Dt' command was specified). For
historical reasons, the horizontal position is changed by adding
the argument to the actual horizontal position, while the vertical
position is not changed. Although this doesn't make sense it is
kept for compatibility. This command is a `gtroff' extension.

File: groff, Node: Device Control Commands, Next: Obsolete Command, Prev: Graphics Commands, Up: Command Reference
8.1.2.4 Device Control Commands
...............................
Each device control command starts with the letter `x', followed by a
space character (optional or arbitrary space or tab in `gtroff') and a
subcommand letter or word; each argument (if any) must be preceded by a
syntactical space. All `x' commands are terminated by a syntactical
line break; no device control command can be followed by another
command on the same line (except a comment).
The subcommand is basically a single letter, but to increase
readability, it can be written as a word, i.e., an arbitrary sequence
of characters terminated by the next tab, space, or newline character.
All characters of the subcommand word but the first are simply ignored.
For example, `gtroff' outputs the initialization command `x i' as
`x init' and the resolution command `x r' as `x res'.
In the following, the syntax element <line break> means a
syntactical line break (*note Separation::).
`xF NAME<line break>'
The `F' stands for FILENAME.
Use NAME as the intended name for the current file in error
reports. This is useful for remembering the original file name
when `gtroff' uses an internal piping mechanism. The input file is
not changed by this command. This command is a `gtroff' extension.
`xf N S<line break>'
The `f' stands for FONT.
Mount font position N (a non-negative integer) with font named S
(a text word). *Note Font Positions::.
`xH N<line break>'
The `H' stands for HEIGHT.
Set glyph height to N (a positive integer in scaled points `z').
AT&T `troff' uses the unit points (`p') instead. *Note Output
Language Compatibility::.
`xi<line break>'
The `i' stands for INIT.
Initialize device. This is the third command of the prologue.
`xp<line break>'
The `p' stands for PAUSE.
Parsed but ignored. The original UNIX troff manual writes
pause device, can be restarted
`xr N H V<line break>'
The `r' stands for RESOLUTION.
Resolution is N, while H is the minimal horizontal motion, and V
the minimal vertical motion possible with this device; all
arguments are positive integers in basic units `u' per inch. This
is the second command of the prologue.
`xS N<line break>'
The `S' stands for SLANT.
Set slant to N (an integer in basic units `u').
`xs<line break>'
The `s' stands for STOP.
Terminates the processing of the current file; issued as the last
command of any intermediate troff output.
`xt<line break>'
The `t' stands for TRAILER.
Generate trailer information, if any. In GTROFF, this is actually
just ignored.
`xT XXX<line break>'
The `T' stands for TYPESETTER.
Set name of device to word XXX, a sequence of characters ended by
the next white space character. The possible device names coincide
with those from the `groff' `-T' option. This is the first
command of the prologue.
`xu N<line break>'
The `u' stands for UNDERLINE.
Configure underlining of spaces. If N is 1, start underlining of
spaces; if N is 0, stop underlining of spaces. This is needed for
the `cu' request in nroff mode and is ignored otherwise. This
command is a `gtroff' extension.
`xX ANYTHING<line break>'
The `x' stands for X-ESCAPE.
Send string ANYTHING uninterpreted to the device. If the line
following this command starts with a `+' character this line is
interpreted as a continuation line in the following sense. The
`+' is ignored, but a newline character is sent instead to the
device, the rest of the line is sent uninterpreted. The same
applies to all following lines until the first character of a line
is not a `+' character. This command is generated by the `gtroff'
escape sequence `\X'. The line-continuing feature is a `gtroff'
extension.

File: groff, Node: Obsolete Command, Prev: Device Control Commands, Up: Command Reference
8.1.2.5 Obsolete Command
........................
In AT&T `troff' output, the writing of a single glyph is mostly done by
a very strange command that combines a horizontal move and a single
character giving the glyph name. It doesn't have a command code, but
is represented by a 3-character argument consisting of exactly 2 digits
and a character.
DDG
Move right DD (exactly two decimal digits) basic units `u', then
print glyph G (represented as a single character).
In `gtroff', arbitrary syntactical space around and within this
command is allowed to be added. Only when a preceding command on
the same line ends with an argument of variable length a
separating space is obligatory. In AT&T `troff', large clusters
of these and other commands are used, mostly without spaces; this
made such output almost unreadable.
For modern high-resolution devices, this command does not make sense
because the width of the glyphs can become much larger than two decimal
digits. In `gtroff', this is only used for the devices `X75',
`X75-12', `X100', and `X100-12'. For other devices, the commands `t'
and `u' provide a better functionality.

File: groff, Node: Intermediate Output Examples, Next: Output Language Compatibility, Prev: Command Reference, Up: gtroff Output
8.1.3 Intermediate Output Examples
----------------------------------
This section presents the intermediate output generated from the same
input for three different devices. The input is the sentence `hell
world' fed into `gtroff' on the command line.
High-resolution device `ps'
This is the standard output of `gtroff' if no `-T' option is given.
shell> echo "hell world" | groff -Z -T ps
x T ps
x res 72000 1 1
x init
p1
x font 5 TR
f5
s10000
V12000
H72000
thell
wh2500
tw
H96620
torld
n12000 0
x trailer
V792000
x stop
This output can be fed into `grops' to get its representation as a
PostScript file.
Low-resolution device `latin1'
This is similar to the high-resolution device except that the
positioning is done at a minor scale. Some comments (lines
starting with `#') were added for clarification; they were not
generated by the formatter.
shell> echo "hell world" | groff -Z -T latin1
# prologue
x T latin1
x res 240 24 40
x init
# begin a new page
p1
# font setup
x font 1 R
f1
s10
# initial positioning on the page
V40
H0
# write text `hell'
thell
# inform about space, and issue a horizontal jump
wh24
# write text `world'
tworld
# announce line break, but do nothing because ...
n40 0
# ... the end of the document has been reached
x trailer
V2640
x stop
This output can be fed into `grotty' to get a formatted text
document.
AT&T `troff' output
Since a computer monitor has a very low resolution compared to
modern printers the intermediate output for the X Window devices
can use the jump-and-write command with its 2-digit displacements.
shell> echo "hell world" | groff -Z -T X100
x T X100
x res 100 1 1
x init
p1
x font 5 TR
f5
s10
V16
H100
# write text with jump-and-write commands
ch07e07l03lw06w11o07r05l03dh7
n16 0
x trailer
V1100
x stop
This output can be fed into `xditview' or `gxditview' for
displaying in X.
Due to the obsolete jump-and-write command, the text clusters in
the AT&T `troff' output are almost unreadable.

File: groff, Node: Output Language Compatibility, Prev: Intermediate Output Examples, Up: gtroff Output
8.1.4 Output Language Compatibility
-----------------------------------
The intermediate output language of AT&T `troff' was first documented
in the UNIX troff manual, with later additions documented in `A
Typesetter-indenpendent TROFF', written by Brian Kernighan.
The `gtroff' intermediate output format is compatible with this
specification except for the following features.
* The classical quasi device independence is not yet implemented.
* The old hardware was very different from what we use today. So the
`groff' devices are also fundamentally different from the ones in
AT&T `troff'. For example, the AT&T PostScript device is called
`post' and has a resolution of only 720 units per inch, suitable
for printers 20 years ago, while `groff''s `ps' device has a
resolution of 72000 units per inch. Maybe, by implementing some
rescaling mechanism similar to the classical quasi device
independence, `groff' could emulate AT&T's `post' device.
* The B-spline command `D~' is correctly handled by the intermediate
output parser, but the drawing routines aren't implemented in some
of the postprocessor programs.
* The argument of the commands `s' and `x H' has the implicit unit
scaled point `z' in `gtroff', while AT&T `troff' has point (`p').
This isn't an incompatibility but a compatible extension, for both
units coincide for all devices without a `sizescale' parameter in
the `DESC' file, including all postprocessors from AT&T and
`groff''s text devices. The few `groff' devices with a
`sizescale' parameter either do not exist for AT&T `troff', have a
different name, or seem to have a different resolution. So
conflicts are very unlikely.
* The position changing after the commands `Dp', `DP', and `Dt' is
illogical, but as old versions of `gtroff' used this feature it is
kept for compatibility reasons.

File: groff, Node: Font Files, Prev: gtroff Output, Up: File formats
8.2 Font Files
==============
The `gtroff' font format is roughly a superset of the `ditroff' font
format (as used in later versions of AT&T `troff' and its descendants).
Unlike the `ditroff' font format, there is no associated binary
format; all files are text files.(1) (*note Font Files-Footnote-1::)
The font files for device NAME are stored in a directory `devNAME'.
There are two types of file: a device description file called `DESC'
and for each font F a font file called `F'.
* Menu:
* DESC File Format::
* Font File Format::

File: groff, Node: Font Files-Footnotes, Up: Font Files
(1) Plan 9 `troff' has also abandoned the binary format.

File: groff, Node: DESC File Format, Next: Font File Format, Prev: Font Files, Up: Font Files
8.2.1 `DESC' File Format
------------------------
The `DESC' file can contain the following types of line. Except for
the `charset' keyword which must comes last (if at all), the order of
the lines is not important.
`res N'
There are N machine units per inch.
`hor N'
The horizontal resolution is N machine units. All horizontal
quantities are rounded to be multiples of this value.
`vert N'
The vertical resolution is N machine units. All vertical
quantities are rounded to be multiples of this value.
`sizescale N'
The scale factor for point sizes. By default this has a value
of 1. One scaled point is equal to one point/N. The arguments to
the `unitwidth' and `sizes' commands are given in scaled points.
*Note Fractional Type Sizes::, for more information.
`unitwidth N'
Quantities in the font files are given in machine units for fonts
whose point size is N scaled points.
`prepro PROGRAM'
Call PROGRAM as a preprocessor. Currently, this keyword is used
by `groff' with option `-Thtml' only.
`postpro PROGRAM'
Call PROGRAM as a postprocessor. For example, the line
postpro grodvi
in the file `devdvi/DESC' makes `groff' call `grodvi' if option
`-Tdvi' is given (and `-Z' isn't used).
`tcommand'
This means that the postprocessor can handle the `t' and `u'
intermediate output commands.
`sizes S1 S2 ... SN 0'
This means that the device has fonts at S1, S2, ... SN scaled
points. The list of sizes must be terminated by 0 (this is digit
zero). Each SI can also be a range of sizes M-N. The list can
extend over more than one line.
`styles S1 S2 ... SM'
The first M font positions are associated with styles S1 ... SM.
`fonts N F1 F2 F3 ... FN'
Fonts F1 ... FN are mounted in the font positions M+1, ..., M+N
where M is the number of styles. This command may extend over
more than one line. A font name of 0 means no font is mounted on
the corresponding font position.
`family FAM'
The default font family is FAM.
`use_charnames_in_special'
This command indicates that `gtroff' should encode special
characters inside special commands. Currently, this is only used
by the HTML output device. *Note Postprocessor Access::.
`papersize STRING ...'
Select a paper size. Valid values for STRING are the ISO paper
types `A0'-`A7', `B0'-`B7', `C0'-`C7', `D0'-`D7', `DL', and the US
paper types `letter', `legal', `tabloid', `ledger', `statement',
`executive', `com10', and `monarch'. Case is not significant for
STRING if it holds predefined paper types. Alternatively, STRING
can be a file name (e.g. `/etc/papersize'); if the file can be
opened, `groff' reads the first line and tests for the above paper
sizes. Finally, STRING can be a custom paper size in the format
`LENGTH,WIDTH' (no spaces before and after the comma). Both
LENGTH and WIDTH must have a unit appended; valid values are `i'
for inches, `C' for centimeters, `p' for points, and `P' for
picas. Example: `12c,235p'. An argument which starts with a
digit is always treated as a custom paper format. `papersize'
sets both the vertical and horizontal dimension of the output
medium.
More than one argument can be specified; `groff' scans from left to
right and uses the first valid paper specification.
`pass_filenames'
Tell `gtroff' to emit the name of the source file currently being
processed. This is achieved by the intermediate output command
`F'. Currently, this is only used by the HTML output device.
`print PROGRAM'
Use PROGRAM as a spooler program for printing. If omitted, the
`-l' and `-L' options of `groff' are ignored.
`charset'
This line and everything following in the file are ignored. It is
allowed for the sake of backwards compatibility.
The `res', `unitwidth', `fonts', and `sizes' lines are mandatory.
Other commands are ignored by `gtroff' but may be used by
postprocessors to store arbitrary information about the device in the
`DESC' file.
Here a list of obsolete keywords which are recognized by `groff' but
completely ignored: `spare1', `spare2', `biggestfont'.

File: groff, Node: Font File Format, Prev: DESC File Format, Up: Font Files
8.2.2 Font File Format
----------------------
A "font file", also (and probably better) called a "font description
file", has two sections. The first section is a sequence of lines each
containing a sequence of blank delimited words; the first word in the
line is a key, and subsequent words give a value for that key.
`name F'
The name of the font is F.
`spacewidth N'
The normal width of a space is N.
`slant N'
The glyphs of the font have a slant of N degrees. (Positive means
forward.)
`ligatures LIG1 LIG2 ... LIGN [0]'
Glyphs LIG1, LIG2, ..., LIGN are ligatures; possible ligatures are
`ff', `fi', `fl', `ffi' and `ffl'. For backwards compatibility,
the list of ligatures may be terminated with a 0. The list of
ligatures may not extend over more than one line.
`special'
The font is "special"; this means that when a glyph is requested
that is not present in the current font, it is searched for in any
special fonts that are mounted.
Other commands are ignored by `gtroff' but may be used by
postprocessors to store arbitrary information about the font in the font
file.
The first section can contain comments which start with the `#'
character and extend to the end of a line.
The second section contains one or two subsections. It must contain
a `charset' subsection and it may also contain a `kernpairs'
subsection. These subsections can appear in any order. Each
subsection starts with a word on a line by itself.
The word `charset' starts the character set subsection.(1) (*note
Font File Format-Footnote-1::) The `charset' line is followed by a
sequence of lines. Each line gives information for one glyph. A line
comprises a number of fields separated by blanks or tabs. The format is
NAME METRICS TYPE CODE [ENTITY-NAME] [`--' COMMENT]
NAME identifies the glyph name(2) (*note Font File Format-Footnote-2::):
If NAME is a single character C then it corresponds to the `gtroff'
input character C; if it is of the form `\C' where C is a single
character, then it corresponds to the special character `\[C]';
otherwise it corresponds to the special character `\[NAME]'. If it is
exactly two characters XX it can be entered as `\(XX'. Note that
single-letter special characters can't be accessed as `\C'; the only
exception is `\-' which is identical to `\[-]'.
`gtroff' supports 8-bit input characters; however some utilities
have difficulties with eight-bit characters. For this reason, there is
a convention that the entity name `charN' is equivalent to the single
input character whose code is N. For example, `char163' would be
equivalent to the character with code 163 which is the pounds sterling
sign in the ISO Latin-1 character set. You shouldn't use `charN'
entities in font description files since they are related to input, not
output. Otherwise, you get hard-coded connections between input and
output encoding which prevents use of different (input) character sets.
The name `---' is special and indicates that the glyph is unnamed;
such glyphs can only be used by means of the `\N' escape sequence in
`gtroff'.
The TYPE field gives the glyph type:
`1'
the glyph has a descender, for example, `p';
`2'
the glyph has an ascender, for example, `b';
`3'
the glyph has both an ascender and a descender, for example, `('.
The CODE field gives the code which the postprocessor uses to print
the glyph. The glyph can also be input to `gtroff' using this code by
means of the `\N' escape sequence. CODE can be any integer. If it
starts with `0' it is interpreted as octal; if it starts with `0x' or
`0X' it is interpreted as hexadecimal. Note, however, that the `\N'
escape sequence only accepts a decimal integer.
The ENTITY-NAME field gives an ASCII string identifying the glyph
which the postprocessor uses to print the `gtroff' glyph NAME. This
field is optional and has been introduced so that the HTML device
driver can encode its character set. For example, the glyph `\[Po]' is
represented as `&pound;' in HTML 4.0.
Anything on the line after the ENTITY-NAME field resp. after `--'
will be ignored.
The METRICS field has the form:
WIDTH[`,'HEIGHT[`,'DEPTH[`,'ITALIC-CORRECTION
[`,'LEFT-ITALIC-CORRECTION[`,'SUBSCRIPT-CORRECTION]]]]]
There must not be any spaces between these subfields (it has been split
here into two lines for better legibility only). Missing subfields are
assumed to be 0. The subfields are all decimal integers. Since there
is no associated binary format, these values are not required to fit
into a variable of type `char' as they are in `ditroff'. The WIDTH
subfield gives the width of the glyph. The HEIGHT subfield gives the
height of the glyph (upwards is positive); if a glyph does not extend
above the baseline, it should be given a zero height, rather than a
negative height. The DEPTH subfield gives the depth of the glyph, that
is, the distance from the baseline to the lowest point below the
baseline to which the glyph extends (downwards is positive); if a glyph
does not extend below the baseline, it should be given a zero depth,
rather than a negative depth. The ITALIC-CORRECTION subfield gives the
amount of space that should be added after the glyph when it is
immediately to be followed by a glyph from a roman font. The
LEFT-ITALIC-CORRECTION subfield gives the amount of space that should
be added before the glyph when it is immediately to be preceded by a
glyph from a roman font. The SUBSCRIPT-CORRECTION gives the amount of
space that should be added after a glyph before adding a subscript.
This should be less than the italic correction.
A line in the `charset' section can also have the format
NAME "
This indicates that NAME is just another name for the glyph mentioned
in the preceding line.
The word `kernpairs' starts the kernpairs section. This contains a
sequence of lines of the form:
C1 C2 N
This means that when glyph C1 appears next to glyph C2 the space
between them should be increased by N. Most entries in the kernpairs
section have a negative value for N.

File: groff, Node: Font File Format-Footnotes, Up: Font File Format
(1) This keyword is misnamed since it starts a list of ordered
glyphs, not characters.
(2) The distinction between input, characters, and output, glyphs,
is not clearly separated in the terminology of `groff'; for example,
the `char' request should be called `glyph' since it defines an output
entity.

File: groff, Node: Installation, Next: Copying This Manual, Prev: File formats, Up: Top
9 Installation
**************

File: groff, Node: Copying This Manual, Next: Request Index, Prev: Installation, Up: Top
Appendix A Copying This Manual
******************************
* Menu:
* GNU Free Documentation License:: License for copying this manual.

File: groff, Node: GNU Free Documentation License, Up: Copying This Manual
A.1 GNU Free Documentation License
==================================
Version 1.2, November 2002
Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
functional and useful document "free" in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not
being considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense.
It complements the GNU General Public License, which is a copyleft
license designed for free software.
We have designed this License in order to use it for manuals for
free software, because free software needs free documentation: a
free program should come with manuals providing the same freedoms
that the software does. But this License is not limited to
software manuals; it can be used for any textual work, regardless
of subject matter or whether it is published as a printed book.
We recommend this License principally for works whose purpose is
instruction or reference.
1. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium,
that contains a notice placed by the copyright holder saying it
can be distributed under the terms of this License. Such a notice
grants a world-wide, royalty-free license, unlimited in duration,
to use that work under the conditions stated herein. The
"Document", below, refers to any such manual or work. Any member
of the public is a licensee, and is addressed as "you". You
accept the license if you copy, modify or distribute the work in a
way requiring permission under copyright law.
A "Modified Version" of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.
A "Secondary Section" is a named appendix or a front-matter section
of the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document's overall
subject (or to related matters) and contains nothing that could
fall directly within that overall subject. (Thus, if the Document
is in part a textbook of mathematics, a Secondary Section may not
explain any mathematics.) The relationship could be a matter of
historical connection with the subject or with related matters, or
of legal, commercial, philosophical, ethical or political position
regarding them.
The "Invariant Sections" are certain Secondary Sections whose
titles are designated, as being those of Invariant Sections, in
the notice that says that the Document is released under this
License. If a section does not fit the above definition of
Secondary then it is not allowed to be designated as Invariant.
The Document may contain zero Invariant Sections. If the Document
does not identify any Invariant Sections then there are none.
The "Cover Texts" are certain short passages of text that are
listed, as Front-Cover Texts or Back-Cover Texts, in the notice
that says that the Document is released under this License. A
Front-Cover Text may be at most 5 words, and a Back-Cover Text may
be at most 25 words.
A "Transparent" copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
general public, that is suitable for revising the document
straightforwardly with generic text editors or (for images
composed of pixels) generic paint programs or (for drawings) some
widely available drawing editor, and that is suitable for input to
text formatters or for automatic translation to a variety of
formats suitable for input to text formatters. A copy made in an
otherwise Transparent file format whose markup, or absence of
markup, has been arranged to thwart or discourage subsequent
modification by readers is not Transparent. An image format is
not Transparent if used for any substantial amount of text. A
copy that is not "Transparent" is called "Opaque".
Examples of suitable formats for Transparent copies include plain
ASCII without markup, Texinfo input format, LaTeX input format,
SGML or XML using a publicly available DTD, and
standard-conforming simple HTML, PostScript or PDF designed for
human modification. Examples of transparent image formats include
PNG, XCF and JPG. Opaque formats include proprietary formats that
can be read and edited only by proprietary word processors, SGML or
XML for which the DTD and/or processing tools are not generally
available, and the machine-generated HTML, PostScript or PDF
produced by some word processors for output purposes only.
The "Title Page" means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the
material this License requires to appear in the title page. For
works in formats which do not have any title page as such, "Title
Page" means the text near the most prominent appearance of the
work's title, preceding the beginning of the body of the text.
A section "Entitled XYZ" means a named subunit of the Document
whose title either is precisely XYZ or contains XYZ in parentheses
following text that translates XYZ in another language. (Here XYZ
stands for a specific section name mentioned below, such as
"Acknowledgements", "Dedications", "Endorsements", or "History".)
To "Preserve the Title" of such a section when you modify the
Document means that it remains a section "Entitled XYZ" according
to this definition.
The Document may include Warranty Disclaimers next to the notice
which states that this License applies to the Document. These
Warranty Disclaimers are considered to be included by reference in
this License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and
has no effect on the meaning of this License.
2. VERBATIM COPYING
You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License
applies to the Document are reproduced in all copies, and that you
add no other conditions whatsoever to those of this License. You
may not use technical measures to obstruct or control the reading
or further copying of the copies you make or distribute. However,
you may accept compensation in exchange for copies. If you
distribute a large enough number of copies you must also follow
the conditions in section 3.
You may also lend copies, under the same conditions stated above,
and you may publicly display copies.
3. COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly
have printed covers) of the Document, numbering more than 100, and
the Document's license notice requires Cover Texts, you must
enclose the copies in covers that carry, clearly and legibly, all
these Cover Texts: Front-Cover Texts on the front cover, and
Back-Cover Texts on the back cover. Both covers must also clearly
and legibly identify you as the publisher of these copies. The
front cover must present the full title with all words of the
title equally prominent and visible. You may add other material
on the covers in addition. Copying with changes limited to the
covers, as long as they preserve the title of the Document and
satisfy these conditions, can be treated as verbatim copying in
other respects.
If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto
adjacent pages.
If you publish or distribute Opaque copies of the Document
numbering more than 100, you must either include a
machine-readable Transparent copy along with each Opaque copy, or
state in or with each Opaque copy a computer-network location from
which the general network-using public has access to download
using public-standard network protocols a complete Transparent
copy of the Document, free of added material. If you use the
latter option, you must take reasonably prudent steps, when you
begin distribution of Opaque copies in quantity, to ensure that
this Transparent copy will remain thus accessible at the stated
location until at least one year after the last time you
distribute an Opaque copy (directly or through your agents or
retailers) of that edition to the public.
It is requested, but not required, that you contact the authors of
the Document well before redistributing any large number of
copies, to give them a chance to provide you with an updated
version of the Document.
4. MODIFICATIONS
You may copy and distribute a Modified Version of the Document
under the conditions of sections 2 and 3 above, provided that you
release the Modified Version under precisely this License, with
the Modified Version filling the role of the Document, thus
licensing distribution and modification of the Modified Version to
whoever possesses a copy of it. In addition, you must do these
things in the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title
distinct from that of the Document, and from those of
previous versions (which should, if there were any, be listed
in the History section of the Document). You may use the
same title as a previous version if the original publisher of
that version gives permission.
B. List on the Title Page, as authors, one or more persons or
entities responsible for authorship of the modifications in
the Modified Version, together with at least five of the
principal authors of the Document (all of its principal
authors, if it has fewer than five), unless they release you
from this requirement.
C. State on the Title page the name of the publisher of the
Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license
notice giving the public permission to use the Modified
Version under the terms of this License, in the form shown in
the Addendum below.
G. Preserve in that license notice the full lists of Invariant
Sections and required Cover Texts given in the Document's
license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled "History", Preserve its Title,
and add to it an item stating at least the title, year, new
authors, and publisher of the Modified Version as given on
the Title Page. If there is no section Entitled "History" in
the Document, create one stating the title, year, authors,
and publisher of the Document as given on its Title Page,
then add an item describing the Modified Version as stated in
the previous sentence.
J. Preserve the network location, if any, given in the Document
for public access to a Transparent copy of the Document, and
likewise the network locations given in the Document for
previous versions it was based on. These may be placed in
the "History" section. You may omit a network location for a
work that was published at least four years before the
Document itself, or if the original publisher of the version
it refers to gives permission.
K. For any section Entitled "Acknowledgements" or "Dedications",
Preserve the Title of the section, and preserve in the
section all the substance and tone of each of the contributor
acknowledgements and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document,
unaltered in their text and in their titles. Section numbers
or the equivalent are not considered part of the section
titles.
M. Delete any section Entitled "Endorsements". Such a section
may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled
"Endorsements" or to conflict in title with any Invariant
Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no
material copied from the Document, you may at your option
designate some or all of these sections as invariant. To do this,
add their titles to the list of Invariant Sections in the Modified
Version's license notice. These titles must be distinct from any
other section titles.
You may add a section Entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text
has been approved by an organization as the authoritative
definition of a standard.
You may add a passage of up to five words as a Front-Cover Text,
and a passage of up to 25 words as a Back-Cover Text, to the end
of the list of Cover Texts in the Modified Version. Only one
passage of Front-Cover Text and one of Back-Cover Text may be
added by (or through arrangements made by) any one entity. If the
Document already includes a cover text for the same cover,
previously added by you or by arrangement made by the same entity
you are acting on behalf of, you may not add another; but you may
replace the old one, on explicit permission from the previous
publisher that added the old one.
The author(s) and publisher(s) of the Document do not by this
License give permission to use their names for publicity for or to
assert or imply endorsement of any Modified Version.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under
this License, under the terms defined in section 4 above for
modified versions, provided that you include in the combination
all of the Invariant Sections of all of the original documents,
unmodified, and list them all as Invariant Sections of your
combined work in its license notice, and that you preserve all
their Warranty Disclaimers.
The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy. If there are multiple Invariant Sections with the same name
but different contents, make the title of each such section unique
by adding at the end of it, in parentheses, the name of the
original author or publisher of that section if known, or else a
unique number. Make the same adjustment to the section titles in
the list of Invariant Sections in the license notice of the
combined work.
In the combination, you must combine any sections Entitled
"History" in the various original documents, forming one section
Entitled "History"; likewise combine any sections Entitled
"Acknowledgements", and any sections Entitled "Dedications". You
must delete all sections Entitled "Endorsements."
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other
documents released under this License, and replace the individual
copies of this License in the various documents with a single copy
that is included in the collection, provided that you follow the
rules of this License for verbatim copying of each of the
documents in all other respects.
You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert
a copy of this License into the extracted document, and follow
this License in all other respects regarding verbatim copying of
that document.
7. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other
separate and independent documents or works, in or on a volume of
a storage or distribution medium, is called an "aggregate" if the
copyright resulting from the compilation is not used to limit the
legal rights of the compilation's users beyond what the individual
works permit. When the Document is included in an aggregate, this
License does not apply to the other works in the aggregate which
are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half
of the entire aggregate, the Document's Cover Texts may be placed
on covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic
form. Otherwise they must appear on printed covers that bracket
the whole aggregate.
8. TRANSLATION
Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section
4. Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections. You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also
include the original English version of this License and the
original versions of those notices and disclaimers. In case of a
disagreement between the translation and the original version of
this License or a notice or disclaimer, the original version will
prevail.
If a section in the Document is Entitled "Acknowledgements",
"Dedications", or "History", the requirement (section 4) to
Preserve its Title (section 1) will typically require changing the
actual title.
9. TERMINATION
You may not copy, modify, sublicense, or distribute the Document
except as expressly provided for under this License. Any other
attempt to copy, modify, sublicense or distribute the Document is
void, and will automatically terminate your rights under this
License. However, parties who have received copies, or rights,
from you under this License will not have their licenses
terminated so long as such parties remain in full compliance.
10. FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of
the GNU Free Documentation License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns. See
`http://www.gnu.org/copyleft/'.
Each version of the License is given a distinguishing version
number. If the Document specifies that a particular numbered
version of this License "or any later version" applies to it, you
have the option of following the terms and conditions either of
that specified version or of any later version that has been
published (not as a draft) by the Free Software Foundation. If
the Document does not specify a version number of this License,
you may choose any version ever published (not as a draft) by the
Free Software Foundation.
A.1.1 ADDENDUM: How to use this License for your documents
----------------------------------------------------------
To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:
Copyright (C) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
If you have Invariant Sections, Front-Cover Texts and Back-Cover
Texts, replace the "with...Texts." line with this:
with the Invariant Sections being LIST THEIR TITLES, with
the Front-Cover Texts being LIST, and with the Back-Cover Texts
being LIST.
If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.
If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License, to
permit their use in free software.

File: groff, Node: Request Index, Next: Escape Index, Prev: Copying This Manual, Up: Top
Appendix B Request Index
************************
Requests appear without the leading control character (normally either
`.' or `'').
[index]
* Menu:
* ab: Debugging. (line 40)
* ad: Manipulating Filling and Adjusting.
(line 52)
* af: Assigning Formats. (line 13)
* aln: Setting Registers. (line 79)
* als: Strings. (line 224)
* am: Writing Macros. (line 107)
* am1: Writing Macros. (line 108)
* ami: Writing Macros. (line 109)
* ami1: Writing Macros. (line 110)
* as: Strings. (line 170)
* as1: Strings. (line 171)
* asciify: Diversions. (line 195)
* backtrace: Debugging. (line 94)
* bd: Artificial Fonts. (line 96)
* blm: Blank Line Traps. (line 7)
* box: Diversions. (line 25)
* boxa: Diversions. (line 26)
* bp: Page Control. (line 7)
* br: Manipulating Filling and Adjusting.
(line 12)
* break: while. (line 73)
* brp: Manipulating Filling and Adjusting.
(line 112)
* c2: Character Translations.
(line 16)
* cc: Character Translations.
(line 10)
* ce: Manipulating Filling and Adjusting.
(line 189)
* cf: I/O. (line 49)
* cflags: Using Symbols. (line 241)
* ch: Page Location Traps. (line 106)
* char: Using Symbols. (line 281)
* chop: Strings. (line 231)
* close: I/O. (line 230)
* color: Colors. (line 7)
* composite: Using Symbols. (line 197)
* continue: while. (line 77)
* cp: Implementation Differences.
(line 23)
* cs: Artificial Fonts. (line 127)
* cu: Artificial Fonts. (line 87)
* da: Diversions. (line 18)
* de: Writing Macros. (line 10)
* de1: Writing Macros. (line 11)
* defcolor: Colors. (line 21)
* dei: Writing Macros. (line 12)
* dei1: Writing Macros. (line 13)
* di: Diversions. (line 17)
* do: Implementation Differences.
(line 24)
* ds: Strings. (line 11)
* ds1: Strings. (line 12)
* dt: Diversion Traps. (line 7)
* ec: Character Translations.
(line 47)
* ecr: Character Translations.
(line 59)
* ecs: Character Translations.
(line 58)
* el: if-else. (line 28)
* em: End-of-input Traps. (line 7)
* eo: Character Translations.
(line 22)
* ev: Environments. (line 38)
* evc: Environments. (line 72)
* ex: Debugging. (line 45)
* fam: Font Families. (line 19)
* fc: Fields. (line 18)
* fchar: Using Symbols. (line 282)
* fcolor: Colors. (line 85)
* fi: Manipulating Filling and Adjusting.
(line 30)
* fl: Debugging. (line 85)
* fp: Font Positions. (line 11)
* fschar: Using Symbols. (line 283)
* fspecial: Special Fonts. (line 18)
* ft <1>: Font Positions. (line 58)
* ft: Changing Fonts. (line 7)
* ftr: Changing Fonts. (line 53)
* gcolor: Colors. (line 51)
* hc: Manipulating Hyphenation.
(line 105)
* hcode: Manipulating Hyphenation.
(line 174)
* hla: Manipulating Hyphenation.
(line 253)
* hlm: Manipulating Hyphenation.
(line 45)
* hpf: Manipulating Hyphenation.
(line 114)
* hpfa: Manipulating Hyphenation.
(line 115)
* hpfcode: Manipulating Hyphenation.
(line 116)
* hw: Manipulating Hyphenation.
(line 61)
* hy: Manipulating Hyphenation.
(line 9)
* hym: Manipulating Hyphenation.
(line 209)
* hys: Manipulating Hyphenation.
(line 224)
* ie: if-else. (line 27)
* if: if-else. (line 10)
* ig: Comments. (line 67)
* in: Line Layout. (line 91)
* it: Input Line Traps. (line 7)
* itc: Input Line Traps. (line 8)
* kern: Ligatures and Kerning.
(line 41)
* lc: Leaders. (line 23)
* length: Strings. (line 204)
* lf: Debugging. (line 10)
* lg: Ligatures and Kerning.
(line 23)
* linetabs: Tabs and Fields. (line 147)
* ll: Line Layout. (line 145)
* ls: Manipulating Spacing.
(line 51)
* lt: Page Layout. (line 60)
* mc: Miscellaneous. (line 76)
* mk: Page Motions. (line 10)
* mso: I/O. (line 41)
* na: Manipulating Filling and Adjusting.
(line 104)
* ne: Page Control. (line 34)
* nf: Manipulating Filling and Adjusting.
(line 41)
* nh: Manipulating Hyphenation.
(line 37)
* nm: Miscellaneous. (line 10)
* nn: Miscellaneous. (line 72)
* nop: if-else. (line 24)
* nr <1>: Auto-increment. (line 11)
* nr: Setting Registers. (line 9)
* nroff: Troff and Nroff Mode.
(line 32)
* ns: Manipulating Spacing.
(line 113)
* nx: I/O. (line 74)
* open: I/O. (line 198)
* opena: I/O. (line 199)
* os: Page Control. (line 55)
* output: Diversions. (line 180)
* pc: Page Layout. (line 89)
* pi: I/O. (line 138)
* pl: Page Layout. (line 10)
* pm: Debugging. (line 64)
* pn: Page Layout. (line 77)
* pnr: Debugging. (line 75)
* po: Line Layout. (line 61)
* ps: Changing Type Sizes. (line 7)
* psbb: Miscellaneous. (line 141)
* pso: I/O. (line 30)
* ptr: Debugging. (line 79)
* pvs: Changing Type Sizes. (line 133)
* rchar: Using Symbols. (line 340)
* rd: I/O. (line 79)
* return: Writing Macros. (line 143)
* rfschar: Using Symbols. (line 341)
* rj: Manipulating Filling and Adjusting.
(line 238)
* rm: Strings. (line 219)
* rn: Strings. (line 216)
* rnn: Setting Registers. (line 75)
* rr: Setting Registers. (line 71)
* rs: Manipulating Spacing.
(line 114)
* rt: Page Motions. (line 11)
* schar: Using Symbols. (line 284)
* shc: Manipulating Hyphenation.
(line 240)
* shift: Parameters. (line 30)
* sizes: Changing Type Sizes. (line 69)
* so: I/O. (line 9)
* sp: Manipulating Spacing.
(line 7)
* special: Special Fonts. (line 17)
* spreadwarn: Debugging. (line 131)
* ss: Manipulating Filling and Adjusting.
(line 134)
* sty: Font Families. (line 61)
* substring: Strings. (line 188)
* sv: Page Control. (line 54)
* sy: I/O. (line 160)
* ta: Tabs and Fields. (line 14)
* tc: Tabs and Fields. (line 139)
* ti: Line Layout. (line 117)
* tkf: Ligatures and Kerning.
(line 60)
* tl: Page Layout. (line 35)
* tm: Debugging. (line 25)
* tm1: Debugging. (line 26)
* tmc: Debugging. (line 27)
* tr: Character Translations.
(line 153)
* trf: I/O. (line 48)
* trin: Character Translations.
(line 154)
* trnt: Character Translations.
(line 245)
* troff: Troff and Nroff Mode.
(line 24)
* uf: Artificial Fonts. (line 91)
* ul: Artificial Fonts. (line 65)
* unformat: Diversions. (line 215)
* vpt: Page Location Traps. (line 17)
* vs: Changing Type Sizes. (line 84)
* warn: Debugging. (line 154)
* warnscale: Debugging. (line 127)
* wh: Page Location Traps. (line 29)
* while: while. (line 10)
* write: I/O. (line 210)
* writec: I/O. (line 211)
* writem: I/O. (line 221)

File: groff, Node: Escape Index, Next: Operator Index, Prev: Request Index, Up: Top
Appendix C Escape Index
***********************
Any escape sequence `\X' with X not in the list below emits a warning,
printing glyph X.
[index]
* Menu:
* \: Using Symbols. (line 139)
* \!: Diversions. (line 133)
* \": Comments. (line 10)
* \#: Comments. (line 50)
* \$: Parameters. (line 19)
* \$*: Parameters. (line 38)
* \$0: Parameters. (line 48)
* \$@: Parameters. (line 39)
* \%: Manipulating Hyphenation.
(line 84)
* \&: Ligatures and Kerning.
(line 102)
* \': Using Symbols. (line 229)
* \): Ligatures and Kerning.
(line 131)
* \*: Strings. (line 13)
* \,: Ligatures and Kerning.
(line 92)
* \-: Using Symbols. (line 238)
* \.: Character Translations.
(line 126)
* \/: Ligatures and Kerning.
(line 80)
* \0: Page Motions. (line 139)
* \<colon>: Manipulating Hyphenation.
(line 85)
* \<RET>: Line Control. (line 43)
* \<SP>: Page Motions. (line 123)
* \?: Diversions. (line 134)
* \\: Character Translations.
(line 68)
* \^: Page Motions. (line 135)
* \`: Using Symbols. (line 234)
* \a: Leaders. (line 18)
* \A: Identifiers. (line 55)
* \b: Drawing Requests. (line 223)
* \B: Expressions. (line 65)
* \C: Using Symbols. (line 191)
* \c: Line Control. (line 44)
* \D: Drawing Requests. (line 71)
* \d: Page Motions. (line 109)
* \E: Character Translations.
(line 70)
* \e: Character Translations.
(line 69)
* \f: Font Positions. (line 59)
* \F: Font Families. (line 21)
* \f: Changing Fonts. (line 8)
* \g: Assigning Formats. (line 75)
* \h: Page Motions. (line 112)
* \H: Artificial Fonts. (line 13)
* \k: Page Motions. (line 203)
* \L: Drawing Requests. (line 50)
* \l: Drawing Requests. (line 16)
* \M: Colors. (line 86)
* \m: Colors. (line 52)
* \N: Using Symbols. (line 207)
* \n <1>: Auto-increment. (line 19)
* \n: Interpolating Registers.
(line 9)
* \O: Suppressing output. (line 7)
* \o: Page Motions. (line 218)
* \p: Manipulating Filling and Adjusting.
(line 113)
* \r: Page Motions. (line 103)
* \R: Setting Registers. (line 10)
* \s: Changing Type Sizes. (line 10)
* \S: Artificial Fonts. (line 45)
* \t: Tabs and Fields. (line 10)
* \u: Page Motions. (line 106)
* \V: I/O. (line 248)
* \v: Page Motions. (line 87)
* \w: Page Motions. (line 147)
* \X: Postprocessor Access.
(line 11)
* \x: Manipulating Spacing.
(line 71)
* \Y: Postprocessor Access.
(line 25)
* \Z: Page Motions. (line 226)
* \z: Page Motions. (line 222)
* \{: if-else. (line 38)
* \|: Page Motions. (line 131)
* \}: if-else. (line 38)
* \~: Page Motions. (line 127)

File: groff, Node: Operator Index, Next: Register Index, Prev: Escape Index, Up: Top
Appendix D Operator Index
*************************
[index]
* Menu:
* !: Expressions. (line 21)
* %: Expressions. (line 8)
* &: Expressions. (line 19)
* (: Expressions. (line 41)
* ): Expressions. (line 41)
* *: Expressions. (line 8)
* +: Expressions. (line 8)
* -: Expressions. (line 8)
* /: Expressions. (line 8)
* <: Expressions. (line 15)
* <=: Expressions. (line 15)
* <?: Expressions. (line 26)
* <colon>: Expressions. (line 19)
* =: Expressions. (line 15)
* ==: Expressions. (line 15)
* >: Expressions. (line 15)
* >=: Expressions. (line 15)
* >?: Expressions. (line 26)

File: groff, Node: Register Index, Next: Macro Index, Prev: Operator Index, Up: Top
Appendix E Register Index
*************************
The macro package or program a specific register belongs to is appended
in brackets.
A register name `x' consisting of exactly one character can be
accessed as `\nx'. A register name `xx' consisting of exactly two
characters can be accessed as `\n(xx'. Register names `xxx' of any
length can be accessed as `\n[xxx]'.
[index]
* Menu:
* $$: Built-in Registers. (line 96)
* % <1>: Page Control. (line 10)
* %: Page Layout. (line 89)
* .$: Parameters. (line 10)
* .a: Manipulating Spacing.
(line 72)
* .A: Built-in Registers. (line 103)
* .b: Artificial Fonts. (line 98)
* .C: Implementation Differences.
(line 25)
* .c: Built-in Registers. (line 73)
* .cdp: Environments. (line 96)
* .ce: Manipulating Filling and Adjusting.
(line 190)
* .cht: Environments. (line 95)
* .color: Colors. (line 8)
* .csk: Environments. (line 97)
* .d: Diversions. (line 62)
* .ev: Environments. (line 39)
* .f: Font Positions. (line 12)
* .F: Built-in Registers. (line 12)
* .fam: Font Families. (line 20)
* .fn: Font Families. (line 24)
* .fp: Font Positions. (line 13)
* .g: Built-in Registers. (line 99)
* .h: Diversions. (line 69)
* .H: Built-in Registers. (line 15)
* .height: Artificial Fonts. (line 16)
* .hla: Manipulating Hyphenation.
(line 254)
* .hlc: Manipulating Hyphenation.
(line 47)
* .hlm: Manipulating Hyphenation.
(line 46)
* .hy: Manipulating Hyphenation.
(line 10)
* .hym: Manipulating Hyphenation.
(line 210)
* .hys: Manipulating Hyphenation.
(line 225)
* .i: Line Layout. (line 94)
* .in: Line Layout. (line 120)
* .int: Line Control. (line 45)
* .j: Manipulating Filling and Adjusting.
(line 53)
* .k: Page Motions. (line 214)
* .kern: Ligatures and Kerning.
(line 42)
* .l: Line Layout. (line 148)
* .L: Manipulating Spacing.
(line 52)
* .lg: Ligatures and Kerning.
(line 24)
* .linetabs: Tabs and Fields. (line 148)
* .ll: Line Layout. (line 149)
* .lt: Page Layout. (line 63)
* .M: Colors. (line 89)
* .m: Colors. (line 55)
* .n: Environments. (line 112)
* .ne: Page Location Traps. (line 118)
* .ns: Manipulating Spacing.
(line 115)
* .o: Line Layout. (line 64)
* .p: Page Layout. (line 13)
* .P: Built-in Registers. (line 108)
* .pe: Page Location Traps. (line 139)
* .pn: Page Layout. (line 80)
* .ps: Fractional Type Sizes.
(line 35)
* .psr: Fractional Type Sizes.
(line 42)
* .pvs: Changing Type Sizes. (line 136)
* .rj: Manipulating Filling and Adjusting.
(line 239)
* .s: Changing Type Sizes. (line 11)
* .slant: Artificial Fonts. (line 46)
* .sr: Fractional Type Sizes.
(line 43)
* .ss: Manipulating Filling and Adjusting.
(line 135)
* .sss: Manipulating Filling and Adjusting.
(line 136)
* .sty: Changing Fonts. (line 11)
* .t: Page Location Traps. (line 97)
* .T: Built-in Registers. (line 114)
* .tabs: Tabs and Fields. (line 15)
* .trunc: Page Location Traps. (line 127)
* .u: Manipulating Filling and Adjusting.
(line 31)
* .v: Changing Type Sizes. (line 87)
* .V: Built-in Registers. (line 23)
* .vpt: Page Location Traps. (line 18)
* .w: Environments. (line 94)
* .warn: Debugging. (line 155)
* .x: Built-in Registers. (line 85)
* .Y: Built-in Registers. (line 93)
* .y: Built-in Registers. (line 89)
* .z: Diversions. (line 61)
* c.: Built-in Registers. (line 74)
* ct: Page Motions. (line 152)
* dl: Diversions. (line 87)
* dn: Diversions. (line 86)
* dw: Built-in Registers. (line 39)
* dy: Built-in Registers. (line 42)
* FAM [ms]: ms Document Control Registers.
(line 110)
* FF [ms]: ms Document Control Registers.
(line 184)
* FI [ms]: ms Document Control Registers.
(line 177)
* FL [ms]: ms Document Control Registers.
(line 170)
* FM [ms]: ms Document Control Registers.
(line 47)
* FPD [ms]: ms Document Control Registers.
(line 221)
* FPS [ms]: ms Document Control Registers.
(line 204)
* FVS [ms]: ms Document Control Registers.
(line 212)
* GROWPS [ms]: ms Document Control Registers.
(line 88)
* GS [ms]: Differences from AT&T ms.
(line 46)
* HM [ms]: ms Document Control Registers.
(line 40)
* HORPHANS [ms]: ms Document Control Registers.
(line 154)
* hours: Built-in Registers. (line 35)
* hp: Page Motions. (line 211)
* HY [ms]: ms Document Control Registers.
(line 101)
* LL [ms]: ms Document Control Registers.
(line 25)
* llx: Miscellaneous. (line 142)
* lly: Miscellaneous. (line 143)
* ln: Built-in Registers. (line 79)
* LT [ms]: ms Document Control Registers.
(line 32)
* MINGW [ms] <1>: Additional ms Macros.
(line 28)
* MINGW [ms]: ms Document Control Registers.
(line 231)
* minutes: Built-in Registers. (line 31)
* mo: Built-in Registers. (line 45)
* nl: Page Control. (line 68)
* opmaxx: Suppressing output. (line 19)
* opmaxy: Suppressing output. (line 19)
* opminx: Suppressing output. (line 19)
* opminy: Suppressing output. (line 19)
* PD [ms]: ms Document Control Registers.
(line 127)
* PI [ms]: ms Document Control Registers.
(line 120)
* PO [ms]: ms Document Control Registers.
(line 16)
* PORPHANS [ms]: ms Document Control Registers.
(line 142)
* PS [ms]: ms Document Control Registers.
(line 57)
* ps4html [grohtml]: grohtml specific registers and strings.
(line 7)
* PSINCR [ms]: ms Document Control Registers.
(line 77)
* QI [ms]: ms Document Control Registers.
(line 134)
* rsb: Page Motions. (line 151)
* rst: Page Motions. (line 150)
* sb: Page Motions. (line 149)
* seconds: Built-in Registers. (line 26)
* skw: Page Motions. (line 154)
* slimit: Debugging. (line 119)
* ssc: Page Motions. (line 153)
* st: Page Motions. (line 148)
* systat: I/O. (line 161)
* urx: Miscellaneous. (line 144)
* ury: Miscellaneous. (line 145)
* VS [ms]: ms Document Control Registers.
(line 67)
* year: Built-in Registers. (line 48)
* yr: Built-in Registers. (line 51)

File: groff, Node: Macro Index, Next: String Index, Prev: Register Index, Up: Top
Appendix F Macro Index
**********************
The macro package a specific macro belongs to is appended in brackets.
They appear without the leading control character (normally `.').
[index]
* Menu:
* 1C [ms]: ms Multiple Columns. (line 13)
* 2C [ms]: ms Multiple Columns. (line 16)
* [ [ms]: ms Insertions. (line 33)
* ] [ms]: ms Insertions. (line 34)
* AB [ms]: ms Cover Page Macros.
(line 60)
* AE [ms]: ms Cover Page Macros.
(line 65)
* AI [ms]: ms Cover Page Macros.
(line 56)
* AM [ms] <1>: Additional ms Macros.
(line 10)
* AM [ms]: ms Strings and Special Characters.
(line 51)
* AT [man]: Miscellaneous man macros.
(line 26)
* AU [ms]: ms Cover Page Macros.
(line 38)
* B [man]: Man font macros. (line 48)
* B [ms]: Highlighting in ms. (line 10)
* B1 [ms]: ms Displays and Keeps.
(line 94)
* B2 [ms]: ms Displays and Keeps.
(line 95)
* BD [ms]: ms Displays and Keeps.
(line 31)
* BI [man]: Man font macros. (line 18)
* BI [ms]: Highlighting in ms. (line 39)
* BR [man]: Man font macros. (line 40)
* BT [man]: Optional man extensions.
(line 21)
* BX [ms]: Highlighting in ms. (line 43)
* CD [ms]: ms Displays and Keeps.
(line 41)
* CT [man]: Optional man extensions.
(line 36)
* CW [man]: Optional man extensions.
(line 39)
* CW [ms] <1>: Additional ms Macros.
(line 19)
* CW [ms]: Highlighting in ms. (line 35)
* DA [ms]: ms Cover Page Macros.
(line 23)
* De [man]: Optional man extensions.
(line 45)
* De [ms]: ms Displays and Keeps.
(line 57)
* DE [ms]: ms Displays and Keeps.
(line 16)
* Ds [man]: Optional man extensions.
(line 42)
* DS [ms]: Additional ms Macros.
(line 14)
* Ds [ms]: ms Displays and Keeps.
(line 56)
* DS [ms]: ms Displays and Keeps.
(line 14)
* DT [man]: Miscellaneous man macros.
(line 10)
* EE [man]: Optional man extensions.
(line 52)
* EF [ms]: ms Headers and Footers.
(line 26)
* EH [ms]: ms Headers and Footers.
(line 24)
* EN [ms]: ms Insertions. (line 28)
* EQ [ms]: ms Insertions. (line 27)
* EX [man]: Optional man extensions.
(line 48)
* FE [ms]: ms Footnotes. (line 15)
* FS [ms]: ms Footnotes. (line 14)
* G [man]: Optional man extensions.
(line 55)
* GL [man]: Optional man extensions.
(line 60)
* HB [man]: Optional man extensions.
(line 65)
* HP [man]: Man usage. (line 98)
* I [man]: Man font macros. (line 53)
* I [ms]: Highlighting in ms. (line 31)
* IB [man]: Man font macros. (line 28)
* ID [ms]: ms Displays and Keeps.
(line 23)
* IP [man]: Man usage. (line 78)
* IP [ms]: Lists in ms. (line 9)
* IR [man]: Man font macros. (line 36)
* IX [ms]: Additional ms Macros.
(line 22)
* KE [ms]: ms Displays and Keeps.
(line 73)
* KF [ms]: ms Displays and Keeps.
(line 77)
* KS [ms]: ms Displays and Keeps.
(line 72)
* LD [ms]: ms Displays and Keeps.
(line 15)
* LG [ms]: Highlighting in ms. (line 52)
* LP [man]: Man usage. (line 68)
* LP [ms]: Paragraphs in ms. (line 10)
* MC [ms]: ms Multiple Columns. (line 19)
* MS [man]: Optional man extensions.
(line 73)
* ND [ms]: ms Cover Page Macros.
(line 28)
* NE [man]: Optional man extensions.
(line 85)
* NH [ms]: Headings in ms. (line 13)
* NL [ms]: Highlighting in ms. (line 64)
* NT [man]: Optional man extensions.
(line 78)
* OF [ms]: ms Headers and Footers.
(line 25)
* OH [ms]: ms Headers and Footers.
(line 23)
* P [man]: Man usage. (line 70)
* P1 [ms]: ms Cover Page Macros.
(line 19)
* PD [man]: Miscellaneous man macros.
(line 15)
* PE [ms]: ms Insertions. (line 21)
* Pn [man]: Optional man extensions.
(line 92)
* PN [man]: Optional man extensions.
(line 88)
* PP [man]: Man usage. (line 69)
* PP [ms]: Paragraphs in ms. (line 9)
* PS [ms]: ms Insertions. (line 20)
* PT [man]: Optional man extensions.
(line 16)
* PX [ms]: ms TOC. (line 65)
* QP [ms]: Paragraphs in ms. (line 13)
* R [man]: Optional man extensions.
(line 98)
* R [ms]: Highlighting in ms. (line 27)
* RB [man]: Man font macros. (line 44)
* RD [ms]: ms Displays and Keeps.
(line 49)
* RE [man]: Man usage. (line 115)
* RE [ms]: Indentation values in ms.
(line 12)
* RI [man]: Man font macros. (line 32)
* RN [man]: Optional man extensions.
(line 101)
* RP [ms]: ms Cover Page Macros.
(line 10)
* RS [man]: Man usage. (line 106)
* RS [ms]: Indentation values in ms.
(line 11)
* SB [man]: Man font macros. (line 14)
* SH [man]: Man usage. (line 32)
* SH [ms]: Headings in ms. (line 43)
* SM [man]: Man font macros. (line 10)
* SM [ms]: Highlighting in ms. (line 58)
* SS [man]: Man usage. (line 41)
* TA [ms]: Tabstops in ms. (line 10)
* TB [man]: Optional man extensions.
(line 70)
* TC [ms]: ms TOC. (line 55)
* TE [ms]: ms Insertions. (line 12)
* TH [man]: Man usage. (line 11)
* TL [ms]: ms Cover Page Macros.
(line 33)
* TP [man]: Man usage. (line 49)
* TS [ms]: ms Insertions. (line 11)
* UC [man]: Miscellaneous man macros.
(line 43)
* UL [ms]: Highlighting in ms. (line 47)
* VE [man]: Optional man extensions.
(line 108)
* VS [man]: Optional man extensions.
(line 104)
* XA [ms]: ms TOC. (line 13)
* XE [ms]: ms TOC. (line 14)
* XP [ms]: Paragraphs in ms. (line 18)
* XS [ms]: ms TOC. (line 12)

File: groff, Node: String Index, Next: Glyph Name Index, Prev: Macro Index, Up: Top
Appendix G String Index
***********************
The macro package or program a specific string belongs to is appended in
brackets.
A string name `x' consisting of exactly one character can be
accessed as `\*x'. A string name `xx' consisting of exactly two
characters can be accessed as `\*(xx'. String names `xxx' of any
length can be accessed as `\*[xxx]'.
[index]
* Menu:
* ! [ms]: ms Strings and Special Characters.
(line 101)
* ' [ms]: ms Strings and Special Characters.
(line 65)
* * [ms]: ms Footnotes. (line 11)
* , [ms]: ms Strings and Special Characters.
(line 74)
* - [ms]: ms Strings and Special Characters.
(line 41)
* . [ms]: ms Strings and Special Characters.
(line 89)
* .T: Built-in Registers. (line 119)
* 3 [ms]: ms Strings and Special Characters.
(line 107)
* 8 [ms]: ms Strings and Special Characters.
(line 104)
* ? [ms]: ms Strings and Special Characters.
(line 98)
* \*[<colon>] [ms]: ms Strings and Special Characters.
(line 80)
* ^ [ms]: ms Strings and Special Characters.
(line 71)
* _ [ms]: ms Strings and Special Characters.
(line 86)
* ` [ms]: ms Strings and Special Characters.
(line 68)
* ABSTRACT [ms]: ms Strings and Special Characters.
(line 15)
* Ae [ms]: ms Strings and Special Characters.
(line 128)
* ae [ms]: ms Strings and Special Characters.
(line 125)
* CF [ms]: ms Headers and Footers.
(line 16)
* CH [ms]: ms Headers and Footers.
(line 11)
* d- [ms]: ms Strings and Special Characters.
(line 119)
* D- [ms]: ms Strings and Special Characters.
(line 116)
* HF [man]: Predefined man strings.
(line 12)
* LF [ms]: ms Headers and Footers.
(line 15)
* LH [ms]: ms Headers and Footers.
(line 10)
* lq [man]: Predefined man strings.
(line 21)
* MONTH1 [ms]: ms Strings and Special Characters.
(line 23)
* MONTH10 [ms]: ms Strings and Special Characters.
(line 32)
* MONTH11 [ms]: ms Strings and Special Characters.
(line 33)
* MONTH12 [ms]: ms Strings and Special Characters.
(line 34)
* MONTH2 [ms]: ms Strings and Special Characters.
(line 24)
* MONTH3 [ms]: ms Strings and Special Characters.
(line 25)
* MONTH4 [ms]: ms Strings and Special Characters.
(line 26)
* MONTH5 [ms]: ms Strings and Special Characters.
(line 27)
* MONTH6 [ms]: ms Strings and Special Characters.
(line 28)
* MONTH7 [ms]: ms Strings and Special Characters.
(line 29)
* MONTH8 [ms]: ms Strings and Special Characters.
(line 30)
* MONTH9 [ms]: ms Strings and Special Characters.
(line 31)
* o [ms]: ms Strings and Special Characters.
(line 92)
* q [ms]: ms Strings and Special Characters.
(line 122)
* Q [ms]: ms Strings and Special Characters.
(line 44)
* R [man]: Predefined man strings.
(line 15)
* REFERENCES [ms]: ms Strings and Special Characters.
(line 11)
* RF [ms]: ms Headers and Footers.
(line 17)
* RH [ms]: ms Headers and Footers.
(line 12)
* rq [man]: Predefined man strings.
(line 22)
* S [man]: Predefined man strings.
(line 9)
* SN [ms]: Headings in ms. (line 22)
* SN-DOT [ms]: Headings in ms. (line 23)
* SN-NO-DOT [ms]: Headings in ms. (line 24)
* th [ms]: ms Strings and Special Characters.
(line 113)
* Th [ms]: ms Strings and Special Characters.
(line 110)
* Tm [man]: Predefined man strings.
(line 18)
* TOC [ms]: ms Strings and Special Characters.
(line 19)
* U [ms]: ms Strings and Special Characters.
(line 45)
* v [ms]: ms Strings and Special Characters.
(line 83)
* www-image-template [grohtml]: grohtml specific registers and strings.
(line 8)
* { [ms]: Highlighting in ms. (line 68)
* } [ms]: Highlighting in ms. (line 69)
* ~ [ms]: ms Strings and Special Characters.
(line 77)

File: groff, Node: Glyph Name Index, Next: Font File Keyword Index, Prev: String Index, Up: Top
Appendix H Glyph Name Index
***************************
A glyph name `xx' consisting of exactly two characters can be accessed
as `\(xx'. Glyph names `xxx' of any length can be accessed as `\[xxx]'.

File: groff, Node: Font File Keyword Index, Next: Program and File Index, Prev: Glyph Name Index, Up: Top
Appendix I Font File Keyword Index
**********************************
[index]
* Menu:
* #: Font File Format. (line 36)
* ---: Font File Format. (line 51)
* biggestfont: DESC File Format. (line 109)
* charset <1>: Font File Format. (line 44)
* charset: DESC File Format. (line 101)
* family <1>: DESC File Format. (line 64)
* family <2>: Font Positions. (line 61)
* family: Changing Fonts. (line 11)
* fonts <1>: DESC File Format. (line 58)
* fonts <2>: Special Fonts. (line 18)
* fonts: Using Symbols. (line 15)
* hor: DESC File Format. (line 14)
* kernpairs: Font File Format. (line 135)
* ligatures: Font File Format. (line 22)
* name: Font File Format. (line 12)
* papersize: DESC File Format. (line 72)
* pass_filenames: DESC File Format. (line 92)
* postpro: DESC File Format. (line 36)
* prepro: DESC File Format. (line 32)
* print: DESC File Format. (line 97)
* res: DESC File Format. (line 11)
* sizes: DESC File Format. (line 49)
* sizescale: DESC File Format. (line 22)
* slant: Font File Format. (line 18)
* spacewidth: Font File Format. (line 15)
* spare1: DESC File Format. (line 109)
* spare2: DESC File Format. (line 109)
* special <1>: Font File Format. (line 28)
* special: Artificial Fonts. (line 116)
* styles <1>: DESC File Format. (line 55)
* styles <2>: Font Positions. (line 61)
* styles <3>: Font Families. (line 76)
* styles: Changing Fonts. (line 11)
* tcommand: DESC File Format. (line 45)
* unitwidth: DESC File Format. (line 28)
* use_charnames_in_special <1>: DESC File Format. (line 67)
* use_charnames_in_special: Postprocessor Access.
(line 17)
* vert: DESC File Format. (line 18)

File: groff, Node: Program and File Index, Next: Concept Index, Prev: Font File Keyword Index, Up: Top
Appendix J Program and File Index
*********************************
[index]
* Menu:
* an.tmac: man. (line 6)
* changebar: Miscellaneous. (line 111)
* composite.tmac: Using Symbols. (line 197)
* cp1047.tmac: Input Encodings. (line 9)
* DESC <1>: Special Fonts. (line 18)
* DESC <2>: Using Symbols. (line 15)
* DESC <3>: Font Positions. (line 61)
* DESC <4>: Font Families. (line 76)
* DESC: Changing Fonts. (line 11)
* DESC file format: DESC File Format. (line 6)
* DESC, and font mounting: Font Positions. (line 37)
* DESC, and use_charnames_in_special: Postprocessor Access.
(line 17)
* ditroff: History. (line 58)
* ec.tmac: Input Encodings. (line 41)
* eqn: ms Insertions. (line 7)
* freeeuro.pfa: Input Encodings. (line 41)
* geqn: Groff Options. (line 6)
* geqn, invocation in manual pages: Preprocessors in man pages.
(line 12)
* ggrn: Groff Options. (line 6)
* gpic: Groff Options. (line 6)
* grap: Groff Options. (line 6)
* grefer: Groff Options. (line 6)
* grefer, invocation in manual pages: Preprocessors in man pages.
(line 12)
* groff: Groff Options. (line 6)
* grog: grog. (line 6)
* grohtml: Miscellaneous man macros.
(line 6)
* gsoelim: Groff Options. (line 6)
* gtbl: Groff Options. (line 6)
* gtbl, invocation in manual pages: Preprocessors in man pages.
(line 12)
* gtroff: Groff Options. (line 6)
* hyphen.us: Manipulating Hyphenation.
(line 161)
* hyphenex.us: Manipulating Hyphenation.
(line 161)
* latin1.tmac: Input Encodings. (line 14)
* latin2.tmac: Input Encodings. (line 18)
* latin9.tmac: Input Encodings. (line 23)
* makeindex: Indices. (line 10)
* man, invocation of preprocessors: Preprocessors in man pages.
(line 12)
* man-old.tmac: man. (line 6)
* man.local <1>: Optional man extensions.
(line 6)
* man.local: Man usage. (line 6)
* man.tmac: man. (line 6)
* man.ultrix: Optional man extensions.
(line 30)
* nrchbar: Miscellaneous. (line 111)
* papersize.tmac: Paper Size. (line 16)
* perl: I/O. (line 171)
* pic: ms Insertions. (line 7)
* post-grohtml: Groff Options. (line 165)
* pre-grohtml: Groff Options. (line 165)
* refer: ms Insertions. (line 7)
* soelim: Debugging. (line 10)
* tbl: ms Insertions. (line 7)
* trace.tmac: Writing Macros. (line 101)
* troffrc <1>: Line Layout. (line 64)
* troffrc <2>: Troff and Nroff Mode.
(line 24)
* troffrc <3>: Manipulating Hyphenation.
(line 161)
* troffrc <4>: Paper Size. (line 16)
* troffrc: Groff Options. (line 80)
* troffrc-end <1>: Troff and Nroff Mode.
(line 24)
* troffrc-end <2>: Manipulating Hyphenation.
(line 161)
* troffrc-end: Groff Options. (line 80)
* tty.tmac: Troff and Nroff Mode.
(line 32)

Local Variables:
coding: iso-8859-1
End:
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