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TROFF
!!!TROFF
NAME
SYNOPSIS
DESCRIPTION
OPTIONS
USAGE
ENVIRONMENT
FILES
SEE ALSO
----
!!NAME


troff - format documents
!!SYNOPSIS


__troff__ [[ __-abivzCERU__ ] [[ __-w__''name'' ]
[[ __-W__''name'' ] [[ __-d__''cs'' ] [[
__-f__''fam'' ] [[ __-m__''name'' ] [[
__-n__''num'' ] [[ __-o__''list'' ] [[
__-r__''cn'' ] [[ __-T__''name'' ] [[
__-F__''dir'' ] [[ __-M__''dir'' ] [[
''files...'' ]


It is possible to have whitespace between a command line
option and its parameter.
!!DESCRIPTION


This manual page describes the GNU version of __troff__,
which is part of the groff document formatting system. It is
highly compatible with UNIX troff. Usually it should be
invoked using the groff command, which will also run
preprocessors and postprocessors in the appropriate order
and with the appropriate options.
!!OPTIONS


__-a__ Generate an ASCII approximation of
the typeset output.


__-b__ Print a backtrace with each warning or error
message. This backtrace should help track down the cause of
the error. The line numbers given in the backtrace may not
always be correct: __troff__'s idea of line numbers gets
confused by __as__ or __am__ requests.


__-i__ Read the standard input after all the named input
files have been processed.


__-v__ Print the version number.


__-w__''name''


Enable warning ''name''. Available warnings are described
in the Warnings subsection below. Multiple __-w__ options
are allowed.


__-W__''name''


Inhibit warning ''name''. Multiple __-W__ options are
allowed.


__-E__ Inhibit all error messages of __troff__. Note
that this doesn't affect messages output to standard error
by macro packages using the __.tm__ or __.tm1__
requests.


__-z__ Suppress formatted output.


__-C__ Enable compatibility mode.


__-d__''cs''


__-d__''name''__=__''s''


Define ''c'' or ''name'' to be a string ''s'';
''c'' must be a one letter name.


__-f__''fam''


Use ''fam'' as the default font family.


__-m__''name''


Read in the file ''name''__.tmac__. If it isn't found,
try __tmac.__''name'' instead. It will be first
searched for in directories given with the __-M__ command
line option, then in directories given in the
__GROFF_TMAC_PATH__ environment variable, then in the
current directory (only if in unsafe mode), the home
directory, /usr/lib/groff/site-tmac,
/usr/share/groff/site-tmac, and
/usr/share/groff/1.17.2/tmac.


__-U__ Unsafe mode. This will enable the following
requests: __.open__, __.opena__, __.pso__,
__.sy__, and __.pi__. For security reasons, these
potentially dangerous requests are disabled otherwise. It
will also add the current directory to the macro search
path.


__-R__ Don't load __troffrc__ and
__troffrc-end__.


__-n__''num''


Number the first page ''num''.


__-o__''list''


Output only pages in ''list'', which is a comma-separated
list of page ranges; ''n'' means print page ''n'',
''m''__-__''n'' means print every page between
''m'' and ''n'', __-__''n'' means print every
page up to ''n'', ''n''__-__ means print every page
from ''n''. __Troff__ will exit after printing the
last page in the list.


__-r__''cn''


__-r__''name''__=__''n''


Set number register ''c'' or ''name'' to ''n'';
''c'' must be a one character name; ''n'' can be any
troff numeric expression.


__-T__''name''


Prepare output for device ''name'', rather than the
default __ps__.


__-F__''dir''


Search in directory (or directory path) ''dir'' for
subdirectories __dev__''name'' (''name'' is the
name of the device) and there for the __DESC__ file and
font files. ''dir'' is scanned before all other font
directories.


__-M__''dir''


Search directory (or directory path) ''dir'' for macro
files. This is scanned before all other macro
directories.
!!USAGE


Only the features not in UNIX troff are described
here.


__Long names__


The names of number registers, fonts,
strings/macros/diversions, special characters can be of any
length. In escape sequences, where you can use
__(__''xx'' for a two character name, you can use
__[[__''xxx''__]__ for a name of arbitrary
length:


__[[__''xxx''__]__


Print the special character called ''xxx''.


__f[[__''xxx''__]__


Set font ''xxx''.


__*[[__''xxx''__]__


Interpolate string ''xxx''.


__n[[__''xxx''__]__


Interpolate number register ''xxx''.


__Fractional pointsizes__


A ''scaled point'' is equal to 1/sizescale points, where
sizescale is specified in the __DESC__ file (1 by
default). There is a new scale indicator __z__ which has
the effect of multiplying by sizescale. Requests and escape
sequences in troff interpret arguments that represent a
pointsize as being in units of scaled points, but they
evaluate each such argument using a default scale indicator
of __z__. Arguments treated in this way are the argument
to the __ps__ request, the third argument to the
__cs__ request, the second and fourth arguments to the
__tkf__ request, the argument to the __H__ escape
sequence, and those variants of the __s__ escape sequence
that take a numeric expression as their
argument.


For example, suppose sizescale is 1000; then a scaled point
will be equivalent to a millipoint; the request __.ps
10.25__ is equivalent to __.ps 10.25z__ and so sets the
pointsize to 10250 scaled points, which is equal to 10.25
points.


The number register __n[[.s]__ returns the pointsize in
points as decimal fraction. There is also a new number
register __n[[.ps]__ that returns the pointsize in scaled
points.


It would make no sense to use the __z__ scale indicator
in a numeric expression whose default scale indicator was
neither __u__ nor __z__, and so __troff__ disallows
this. Similarly it would make no sense to use a scaling
indicator other than __z__ or __u__ in a numeric
expression whose default scale indicator was __z__, and
so __troff__ disallows this as well.


There is also new scale indicator __s__ which multiplies
by the number of units in a scaled point. So, for example,
__n[[.ps]s__ is equal to __1m__. Be sure not to confuse
the __s__ and __z__ scale indicators.


__Numeric expressions__


Spaces are permitted in a number expression within
parentheses.


__M__ indicates a scale of 100ths of an em.


''e1''____''e2''


The maximum of ''e1'' and ''e2''.


''e1''____''e2''


The minimum of ''e1'' and ''e2''.


__(__''c''__;__''e''__)__


Evaluate ''e'' using ''c'' as the default scaling
indicator. If ''c'' is missing, ignore scaling indicators
in the evaluation of ''e''.


__New escape sequences__


__A'__''anything''__'__


This expands to __1__ or __0__ according as
''anything'' is or is not acceptable as the name of a
string, macro, diversion, number register, environment or
font. It will return __0__ if ''anything'' is empty.
This is useful if you want to lookup user input in some sort
of associative table.


__B'__''anything''__'__


This expands to __1__ or __0__ according as
''anything'' is or is not a valid numeric expression. It
will return __0__ if ''anything'' is
empty.


__C'__''xxx''__'__


Typeset character named ''xxx''. Normally it is more
convenient to use __[[__''xxx''__]__. But __C__
has the advantage that it is compatible with recent versions
of UNIX and is available in compatibility
mode.


__E__


This is equivalent to an escape character, but it's not
interpreted in copy-mode. For example, strings to start and
end superscripting could be defined like this:


.ds { v'-.3m's'En[[.s]*6u/10u'
.ds } s0v'.3m'


The use of __E__ ensures that these definitions will work
even if __*{__ gets interpreted in copy-mode (for
example, by being used in a macro argument).


__N'__''n''__'__


Typeset the character with code ''n'' in the current
font. ''n'' can be any integer. Most devices only have
characters with codes between 0 and 255. If the current font
does not contain a character with that code, special fonts
will ''not'' be searched. The __N__ escape sequence
can be conveniently used on conjunction with the __char__
request:


__.char [[phone] f(ZDN'37'__


The code of each character is given in the fourth column in
the font description file after the __charset__ command.
It is possible to include unnamed characters in the font
description file by using a name of __---__; the __N__
escape sequence is the only way to use these.


__R'__''name n''__'__


This has the same effect as


__.nr__ ''name n''


__s(__''nn''


__s(__''nn''


Set the point size to ''nn'' points; ''nn'' must be
exactly two digits.


__s[[__''n''__]__


__s[[__''n''__]__


__s'__''n''__'__


__s'__''n''__'__


Set the point size to ''n'' scaled points; ''n'' is a
numeric expression with a default scale indicator of
__z__.


__V__''x''


__V(__''xx''


__V[[__''xxx''__]__


Interpolate the contents of the environment variable
''xxx'', as returned by getenv(3). __V__ is
interpreted in copy-mode.


__Y__''x''


__Y(__''xx''


__Y[[__''xxx''__]__


This is approximately equivalent to
__X'*[[__''xxx''__]'__. However the contents of the
string or macro ''xxx'' are not interpreted; also it is
permitted for ''xxx'' 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
will confuse drivers that do not know about this
extension.


__Z'__''anything''__'__


Print anything and then restore the horizontal and vertical
position; ''anything'' may not contain tabs or
leaders.


__$0__


The name by which the current macro was invoked. The
__als__ request can make a macro have more than one
name.


__$*__


In a macro, the concatenation of all the arguments separated
by spaces.


__$@__


In a macro, the concatenation of all the arguments with each
surrounded by double quotes, and separated by
spaces.


__$(__''nn''


__$[[__''nnn''__]__


In a macro, this gives the ''nn''-th or ''nnn''-th
argument. Macros can have an unlimited number of
arguments.


__?__''anything''__?__


When used in a diversion, this will transparently embed
''anything'' in the diversion. ''anything'' is read in
copy mode. When the diversion is reread, ''anything''
will be interpreted. ''anything'' may not contain
newlines; use __!__ if you want to embed newlines in a
diversion. The escape sequence __?__ is also recognised
in copy mode and turned into a single internal code; it is
this code that terminates ''anything''. Thus


__.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
__


will print __4__.


__/__


This increases the width of the preceding character so that
the spacing between that character and the following
character will be correct if the following character is a
roman character. For example, if an italic f is immediately
followed by a roman right parenthesis, then in many fonts
the top right portion of the f will overlap the top left of
the right parenthesis producing ''f''), which is ugly.
Inserting __/__ produces ''f'') and avoids this
problem. It is a good idea to use this escape sequence
whenever an italic character is immediately followed by a
roman character without any intervening space.


__,__


This modifies the spacing of the following character so that
the spacing between that character and the preceding
character will correct if the preceding character is a roman
character. For example, inserting __,__ between the
parenthesis and the f changes (''f'' to (''f''. It is
a good idea to use this escape sequence whenever a roman
character is immediately followed by an italic character
without any intervening space.


__)__


Like ____ except that it behaves like a character
declared with the __cflags__ request to be transparent
for the purposes of end of sentence
recognition.


__~__


This produces an unbreakable space that stretches like a
normal inter-word space when a line is
adjusted.


__:__


This causes the insertion of a zero-width break point. It is
equal to __%__ but without insertion of a soft hyphen
character.


__#__


Everything up to and including the next newline is ignored.
This is interpreted in copy mode. This is like ____
except that ____ does not ignore the terminating
newline.


__New requests__


__.aln__ ''xx yy''


Create an alias ''xx'' for number register object named
''yy''. The new name and the old name will be exactly
equivalent. If ''yy'' is undefined, a warning of type
__reg__ will be generated, and the request will be
ignored.


__.als__ ''xx yy''


Create an alias ''xx'' for request, string, macro, or
diversion object named ''yy''. The new name and the old
name will be exactly equivalent (it is similar to a hard
rather than a soft link). If ''yy'' is undefined, a
warning of type __mac__ will be generated, and the
request will be ignored. The __de__, __am__,
__di__, __da__, __ds__, and __as__ requests only
create a new object if the name of the macro, diversion or
string diversion is currently undefined or if it is defined
to be a request; normally they modify the value of an
existing object.


__.am1__ ''xx yy''


Similar to __.am__, but compatibility mode is switched
off during execution. On entry, the current compatibility
mode is saved and restored at exit.


__.asciify__ ''xx''


This request `unformats' the diversion ''xx'' in such a
way that ASCII and space characters (and some
escape sequences) that were formatted and diverted into
''xx'' will be treated like ordinary input characters
when ''xx'' is reread. Useful for diversions in
conjunction with the __.writem__ request. It can be also
used for gross hacks; for example, this


__.tr @.
.di x
@nr n 1
.br
.di
.tr @@
.asciify x
.x
__


will set register __n__ to 1. Note that glyph information
(font, font size, etc.) is not preserved; use
__.unformat__ instead.


__.backtrace__


Print a backtrace of the input stack on stderr.


__.blm__ ''xx''


Set the blank line macro to ''xx''. If there is a blank
line macro, it will be invoked when a blank line is
encountered instead of the usual troff
behaviour.


__.box__ ''xx''


__.boxa__ ''xx''


These requests are similar to the __di__ and __da__
requests with the exception that a partially filled line
will not become part of the diversion (i.e., the diversion
always starts with a new line) but restored after ending the
diversion, discarding the partially filled line which
possibly comes from the diversion.


__.break__


Break out of a while loop. See also the __while__ and
__continue__ requests. Be sure not to confuse this with
the __br__ request.


__.brp__


This is the same as __p__.


__.cflags__ ''n c1 c2...''


Characters ''c1'', ''c2'',... have properties
determined by ''n'', which is ORed from the
following:


1


the character ends sentences (initially characters
__.?!__ have this property);


2


lines can be broken before the character (initially no
characters have this property); a line will not be broken at
a character with this property unless the characters on each
side both have non-zero hyphenation codes.


4


lines can be broken after the character (initially
characters __-__ have this property); a line will not be
broken at a character with this property unless the
characters on each side both have non-zero hyphenation
codes.


8


the character overlaps horizontally (initially characters
____ have this property);


16


the character overlaps vertically (initially character
____ has this property);


32


an end of sentence character followed by any number of
characters with this property will be treated as the end of
a sentence if followed by a newline or two spaces; in other
words the character is transparent for the purposes of end
of sentence recognition; this is the same as having a zero
space factor in TEX (initially characters ____
have this property).


__.char__ ''c string''


Define character ''c'' to be ''string''. Every time
character ''c'' needs to be printed, ''string'' will
be processed in a temporary environment and the result will
be wrapped up into a single object. Compatibility mode will
be turned off and the escape character will be set to
__\__ while ''string'' is being processed. Any
emboldening, constant spacing or track kerning will be
applied to this object rather than to individual characters
in ''string''. A character defined by this request can be
used just like a normal character provided by the output
device. In particular other characters can be translated to
it with the __tr__ request; it can be made the leader
character by the __lc__ request; repeated patterns can be
drawn with the character using the __l__ and __L__
escape sequences; words containing the character can be
hyphenated correctly, if the __hcode__ request is used to
give the character a hyphenation code. There is a special
anti-recursion feature: use of character within the
character's definition will be handled like normal
characters not defined with __char__. A character
definition can be removed with the __rchar__
request.


__.chop__ ''xx''


Chop the last character off macro, string, or diversion
''xx''. This is useful for removing the newline from the
end of diversions that are to be interpolated as
strings.


__.close__ ''stream''


Close the stream named ''stream''; ''stream'' will no
longer be an acceptable argument to the __write__
request. See the __open__ request.


__.continue__


Finish the current iteration of a while loop. See also the
__while__ and __break__ requests.


__.cp__ ''n''


If ''n'' is non-zero or missing, enable compatibility
mode, otherwise disable it. In compatibility mode, long
names are not recognised, and the incompatibilities caused
by long names do not arise.


__.dei__ ''xx yy''


Define macro indirectly. The following example


__.ds xx aa
.ds yy bb
.dei xx yy
__


is equivalent to


__.de aa bb__


__.de1__ ''xx yy''


Similar to __.de__, but compatibility mode is switched
off during execution. On entry, the current compatibility
mode is saved and restored at exit.


__.do__ ''xxx''


Interpret ''.xxx'' with compatibility mode disabled. For
example,


__.do fam T__


would have the same effect as


__.fam T__


except that it would work even if compatibility mode had
been enabled. Note that the previous compatibility mode is
restored before any files sourced by ''xxx'' are
interpreted.


__.ecs__


Save current escape character.


__.ecr__


Restore escape character saved with __ecs__. Without a
previous call to __ecs__, `__\__' will be the new
escape character.


__.evc__ ''xx''


Copy the contents of environment ''xx'' to the current
environment. No pushing or popping of environents will be
done.


__.fam__ ''xx''


Set the current font family to ''xx''. The current font
family is part of the current environment. If ''xx'' is
missing, switch back to previous font family. See the
description of the __sty__ request for more information
on font families.


__.fspecial__ ''f s1 s2...''


When the current font is ''f'', fonts ''s1'',
''s2'',... will be special, that is, they will searched
for characters not in the current font. Any fonts specified
in the __special__ request will be searched after fonts
specified in the __fspecial__ request.


__.ftr__ ''f g''


Translate font ''f'' to ''g''. Whenever a font named
''f'' is referred to in __f__ escape sequence, or in
the __ft__, __ul__, __bd__, __cs__, __tkf__,
__special__, __fspecial__, __fp__, or __sty__
requests, font ''g'' will be used. If ''g'' is
missing, or equal to ''f'' then font ''f'' will not be
translated.


__.hcode__ ''c1 code1 c2 code2...''


Set the hyphenation code of character ''c1'' to
''code1'' and that of ''c2'' to ''code2''. A
hyphenation code must be a single input character (not a
special character) other than a digit or a space. Initially
each lower-case letter has a hyphenation code, which is
itself, and each upper-case letter has a hyphenation code
which is the lower case version of itself. See also the
__hpf__ request.


__.hla__ ''lang''


Set the current hyphenation language to ''lang''.
Hyphenation exceptions specified with the __hw__ request
and hyphenation patterns specified with the __hpf__
request are both associated with the current hyphenation
language. The __hla__ request is usually invoked by the
__troffrc__ file.


__.hlm__ ''n''


Set the maximum number of consecutive hyphenated lines to
''n''. If ''n'' is negative, there is no maximum. The
default value is -1. This value is associated with the
current environment. Only lines output from an environment
count towards the maximum associated with that environment.
Hyphens resulting from __%__ are counted; explicit
hyphens are not.


__.hpf__ ''file''


Read hyphenation patterns from ''file''; this will be
searched for in the same way that ''name''__.tmac__ is
searched for when the __-m__''name'' option is
specified. It should have the same format as the argument to
the patterns primitive in TEX; the letters appearing in this
file are interpreted as hyphenation codes. A __%__
character in the patterns file introduces a comment that
continues to the end of the line. The set of hyphenation
patterns is associated with the current language set by the
__hla__ request. The __hpf__ request is usually
invoked by the __troffrc__ file.


__.hym__ ''n''


Set the ''hyphenation margin'' to ''n'': when the
current adjustment mode is not __b__, the line will not
be hyphenated if the line is no more than ''n'' short.
The default hyphenation margin is 0. The default scaling
indicator for this request is ''m''. The hyphenation
margin is associated with the current environment. The
current hyphenation margin is available in the
__n[[.hym]__ register.


__.hys__ ''n''


Set the ''hyphenation space'' to ''n'': when the
current adjustment mode is __b__ don't hyphenate the line
if the line can be justified by adding no more than ''n''
extra space to each word space. The default hyphenation
space is 0. The default scaling indicator for this request
is __m__. The hyphenation space is associated with the
current environment. The current hyphenation space is
available in the __n[[.hys]__ register.


__.kern__ ''n''


If ''n'' is non-zero or missing, enable pairwise kerning,
otherwise disable it.


__.length__ ''xx string''


Compute the length of ''string'' and return it in the
number register ''xx'' (which is not necessarily defined
before).


__.linetabs__ ''n''


If ''n'' is non-zero or missing, enable line-tabs mode,
otherwise disable it (which is the default). In line-tabs
mode, tab distances are computed relative to the (current)
output line. Otherwise they are taken relative to the input
line. For example, the following


__.ds x atc
.ds y btc
.ds z c
.ta 1i 3i
*x
*y
*z
__


yields


a b c


In line-tabs mode, the same code gives


a b c


Line-tabs mode is associated with the current environment;
the read-only number register __n[[.linetabs]__ is set to
1 if in line-tabs mode, and 0 otherwise.


__.mso__ ''file''


The same as the __so__ request except that ''file'' is
searched for 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''
instead and vice versa.


__.nop__ ''anything''


Execute ''anything''. This is similar to `.if
1'.


__.nroff__


Make the __n__ built-in condition true and the __t__
built-in condition false. This can be reversed using the
__troff__ request.


__.open__ ''stream filename''


Open ''filename'' for writing and associate the stream
named ''stream'' with it. See also the __close__ and
__write__ requests.


__.opena__ ''stream filename''


Like __open__, but if ''filename'' exists, append to
it instead of truncating it.


__.pnr__


Print the names and contents of all currently defined number
registers on stderr.


__.psbb__ ''filename''


Get the bounding box of a !PostScript image ''filename''.
This file must conform to Adobe's Document Structuring
Conventions; the command looks for a __%%!BoundingBox__
comment to extract the bounding box values. After a
successful call, the coordinates (in !PostScript units) of
the lower left and upper right corner can be found in the
registers __n[[llx]__, __n[[lly]__, __n[[urx]__, and
__n[[ury]__, respectively. If some error has occurred, the
four registers are set to zero.


__.pso__ ''command''


This behaves like the __so__ request except that input
comes from the standard output of
''command''.


__.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.


__.rchar__ ''c1 c2...''


Remove the definitions of characters ''c1'',
''c2'',... This undoes the effect of a __char__
request.


__.return__


Within a macro, return immediately. No effect
otherwise.


__.rj__


__.rj__ ''n''


Right justify the next ''n'' input lines. Without an
argument right justify the next input line. The number of
lines to be right justified is available in the
__n[[.rj]__ register. This implicitly does __.ce 0__.
The __ce__ request implicitly does __.rj
0__.


__.rnn__ ''xx yy''


Rename number register ''xx'' to ''yy''.


__.shc__ ''c''


Set the soft hyphen character to ''c''. If ''c'' is
omitted, the soft hyphen character will be set to the
default __-__. The soft hyphen character is the character
which will be inserted when a word is hyphenated at a line
break. If the soft hyphen character does not exist in the
font of the character immediately preceding a potential
break point, then the line will not be broken at that point.
Neither definitions (specified with the __char__ request)
nor translations (specified with the __tr__ request) are
considered when finding the soft hyphen
character.


__.shift__ ''n''


In a macro, shift the arguments by ''n'' positions:
argument ''i'' becomes argument ''i''-''n'';
arguments 1 to ''n'' will no longer be available. If
''n'' is missing, arguments will be shifted by 1.
Shifting by negative amounts is currently
undefined.


__.special__ ''s1 s2...''


Fonts ''s1'', ''s2'', are special and will be searched
for characters not in the current font.


__.sty__ ''n f''


Associate style ''f'' with font position ''n''. A font
position can be associated either with a font or with a
style. The current font is the index of a font position and
so is also either a font or a style. When it is a style, the
font that is actually used is the font the name of which is
the concatenation of the name of the current family and the
name of the current style. For example, if the current font
is 1 and font position 1 is associated with style __R__
and the current font family is __T__, then font __TR__
will be used. If the current font is not a style, then the
current family is ignored. When the requests __cs__,
__bd__, __tkf__, __uf__, or __fspecial__ are
applied to a style, then they will instead be applied to the
member of the current family corresponding to that style.
The default family can be set with the __-f__ option. The
styles command in the DESC file controls
which font positions (if any) are initially associated with
styles rather than fonts.


__.substring__ ''xx n1''
__[[__''n2''__]__


Replace the string in register ''xx'' with the substring
defined by the indices ''n1'' and ''n2''. The first
character in the string has index one. If ''n2'' is
omitted, it is taken to be equal to the string's length. If
the index value ''n1'' or ''n2'' is negative or zero,
it will be counted from the end of the string, going
backwards: The last character has index 0, the character
before the last character has index -1, etc.


__.tkf__ ''f s1 n1 s2 n2''


Enable track kerning for font ''f''. When the current
font is ''f'' the width of every character will be
increased by an amount between ''n1'' and ''n2''; when
the current point size is less than or equal to ''s1''
the width will be increased by ''n1''; when it is greater
than or equal to ''s2'' the width will be increased by
''n2''; when the point size is greater than or equal to
''s1'' and less than or equal to ''s2'' the increase
in width is a linear function of the point
size.


__.tm1__ ''string''


Similar to the __tm__ request, ''string'' is read in
copy mode and written on the standard error, but an initial
double quote in ''string'' is stripped off to allow
initial blanks.


__.tmc__ ''string''


Similar to __tm1__ but without writing a final
newline.


__.trf__ ''filename''


Transparently output the contents of file ''filename''.
Each line is output as it would be were it preceded by
__!__; however, the lines are not subject to copy-mode
interpretation. If the file does not end with a newline,
then a newline will be added. For example, you can define a
macro ''x'' containing the contents of file ''f'',
using


__.di__ ''x''__
.trf__ ''f''__
.di__


Unlike with the __cf__ request, the file cannot contain
characters such as NUL that are not legal
troff input characters.


__.trnt abcd__


This is the same as the __tr__ request except that the
translations do not apply to text that is transparently
throughput into a diversion with __!__. For
example,


__.tr ab
.di x
!.tm a
.di
.x
__


will print __b__; if __trnt__ is used instead of
__tr__ it will print __a__.


__.troff__


Make the __n__ built-in condition false, and the __t__
built-in condition true. This undoes the effect of the
__nroff__ request.


__.unformat__ ''xx''


This request `unformats' the diversion ''xx''. Contrary
to the __.asciify__ request, which tries to convert
formatted elements of the diversion back to input tokens as
much as possible, __.unformat__ will only handle tabs and
spaces between words (usually caused by spaces or newlines
in the input) specially. The former are treated as if they
were input tokens, and the latter are stretchable again.
Note that the vertical size of lines is not preserved. Glyph
information (font, font size, space width, etc.) is
retained. Useful in conjunction with the __.box__ and
__.boxa__ requests.


__.vpt__ ''n''


Enable vertical position traps if ''n'' is non-zero,
disable 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.


__.warn__ ''n''


Control warnings. ''n'' is the sum of the numbers
associated with each warning that is to be enabled; all
other warnings will be disabled. The number associated with
each warning is listed in the `Warnings' section. For
example, __.warn 0__ will disable all warnings, and
__.warn 1__ will disable all warnings except that about
missing characters. If ''n'' is not given, all warnings
will be enabled.


__.while__ ''c anything''


While condition ''c'' is true, accept ''anything'' as
input; ''c'' can be any condition acceptable to an
__if__ request; ''anything'' can comprise multiple
lines if the first line starts with __{__ and the last
line ends with __}__. See also the __break__ and
__continue__ requests.


__.write__ ''stream anything''


Write ''anything'' to the stream named ''stream''.
''stream'' must previously have been the subject of an
__open__ request. ''anything'' is read in copy mode; a
leading ____ will be stripped.


__.writem__ ''stream xx''


Write the contents of the macro or string ''xx'' to the
stream named ''stream''. ''stream'' must previously
have been the subject of an __open__ request. ''xx''
is read in copy mode.


__Extended requests__


__.cf__ ''filename''


When used in a diversion, this will embed in the diversion
an object which, when reread, will cause the contents of
''filename'' to be transparently copied through to the
output. In UNIX troff, the contents of ''filename'' 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.


__.ev__ ''xx''


If ''xx'' is not a number, this will switch to a named
environment called ''xx''. The environment should be
popped with a matching __ev__ request without any
arguments, just as for numbered environments. There is no
limit on the number of named environments; they will be
created the first time that they are
referenced.


__.fp__ ''n f1 f2''


The __fp__ request has an optional third argument. This
argument gives the external name of the font, which is used
for finding the font description file. The second argument
gives the internal name of the font which is used to refer
to the font in troff after it has been mounted. If there is
no third argument then the internal name will be used as the
external name. This feature allows you to use fonts with
long names in compatibility mode.


__.ss__ ''m n''


When two arguments are given to the __ss__ request, the
second argument gives the ''sentence space size''. If the
second argument is not given, the sentence space size will
be the same as the word space size. Like the word space
size, the sentence space is in units of one twelfth of the
spacewidth parameter for the current font. Initially both
the word space size and the sentence space size are 12.
Contrary to UNIX troff, GNU troff handles this request in
nroff mode also; a given value is then rounded down to the
nearest multiple of 12. The sentence space size is used in
two circumstances: if the end of a sentence occurs at the
end of a line in fill mode, then both an inter-word space
and a sentence space will be added; if two spaces follow the
end of a sentence in the middle of a line, then the second
space will be a sentence space. Note that the behaviour of
UNIX troff will be exactly that exhibited by GNU troff if a
second argument is never given to the __ss__ request. In
GNU troff, as in UNIX troff, you should always follow a
sentence with either a newline or two spaces.


__.ta__ ''n1 n2...nn'' __T__ ''r1
r2...rn''


Set tabs at positions ''n1'', ''n2'',..., ''nn''
and then set tabs at ''nn''+''r1'',
''nn''+''r2'',...., ''nn''+''rn'' and then at
''nn''+''rn''+''r1'',
''nn''+''rn''+''r2'',...,
''nn''+''rn''+''rn'', and so on. For
example,


__.ta T .5i__


will set tabs every half an inch.


__New number registers__


The following read-only registers are
available:


__n[[.C]__


1 if compatibility mode is in effect, 0
otherwise.


__n[[.cdp]__


The depth of the last character added to the current
environment. It is positive if the character extends below
the baseline.


__n[[.ce]__


The number of lines remaining to be centered, as set by the
__ce__ request.


__n[[.cht]__


The height of the last character added to the current
environment. It is positive if the character extends above
the baseline.


__n[[.csk]__


The skew of the last character added to the current
environment. The ''skew'' of a character is how far to
the right of the center of a character the center of an
accent over that character should be placed.


__n[[.ev]__


The name or number of the current environment. This is a
string-valued register.


__n[[.fam]__


The current font family. This is a string-valued
register.


__n[[.fp]__


The number of the next free font position.


__n[[.g]__


Always 1. Macros should use this to determine whether they
are running under GNU troff.


__n[[.hla]__


The current hyphenation language as set by the __hla__
request.


__n[[.hlc]__


The number of immediately preceding consecutive hyphenated
lines.


__n[[.hlm]__


The maximum allowed number of consecutive hyphenated lines,
as set by the __hlm__ request.


__n[[.hy]__


The current hyphenation flags (as set by the __hy__
request).


__n[[.hym]__


The current hyphenation margin (as set by the __hym__
request).


__n[[.hys]__


The current hyphenation space (as set by the __hys__
request).


__n[[.in]__


The indent that applies to the current output
line.


__n[[.int]__


Set to a positive value if last output line is interrupted
(i.e., if it contains ''c'').


__n[[.kern]__


__1__ if pairwise kerning is enabled, __0__
otherwise.


__n[[.lg]__


The current ligature mode (as set by the __lg__
request).


__n[[.linetabs]__


The current line-tabs mode (as set by the __linetabs__
request).


__n[[.ll]__


The line length that applies to the current output
line.


__n[[.lt]__


The title length as set by the __lt__
request.


__n[[.ne]__


The amount of space that was needed in the last __ne__
request that caused a trap to be sprung. Useful in
conjunction with the __n[[.trunc]__ register.


__n[[.ns]__


__1__ if no-space mode is active, __0__
otherwise.


__n[[.pn]__


The number of the next page: either the value set by a
__pn__ request, or the number of the current page plus
1.


__n[[.ps]__


The current pointsize in scaled points.


__n[[.psr]__


The last-requested pointsize in scaled points.


__n[[.rj]__


The number of lines to be right-justified as set by the
__rj__ request.


__n[[.sr]__


The last requested pointsize in points as a decimal
fraction. This is a string-valued register.


__n[[.tabs]__


A string representation of the current tab settings suitable
for use as an argument to the __ta__
request.


__n[[.trunc]__


The amount of vertical space truncated by the most recently
sprung vertical position trap, or, if the trap was sprung by
a __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. Useful in
conjunction with the __n[[.ne]__ register.


__n[[.ss]__


__n[[.sss]__


These give the values of the parameters set by the first and
second arguments of the __ss__ request.


__n[[.vpt]__


1 if vertical position traps are enabled, 0
otherwise.


__n[[.warn]__


The sum of the numbers associated with each of the currently
enabled warnings. The number associated with each warning is
listed in the `Warnings' subsection.


__n[[.x]__


The major version number. For example, if the version number
is __1.03__ then __n[[.x]__ will contain
__1__.


__n[[.y]__


The minor version number. For example, if the version number
is __1.03__ then __n[[.y]__ will contain
__03__.


__n[[.Y]__


The revision number of groff.


__n[[llx]__


__n[[lly]__


__n[[urx]__


__n[[ury]__


These four registers are set by the __.psbb__ request and
contain the bounding box values (in !PostScript units) of a
given !PostScript image.


The following read/write registers are set by the __w__
escape sequence:


__n[[rst]__


__n[[rsb]__


Like the __st__ and __sb__ registers, but takes
account of the heights and depths of
characters.


__n[[ssc]__


The amount of horizontal space (possibly negative) that
should be added to the last character before a
subscript.


__n[[skw]__


How far to right of the center of the last character in the
__w__ argument, the center of an accent from a roman font
should be placed over that character.


Other available read/write number registers
are:


__n[[c.]__


The current input line number. __n[[.c]__ is a read-only
alias to this register.


__n[[hp]__


The current horizontal position at input line.


__n[[systat]__


The return value of the system() function executed by the
last __sy__ request.


__n[[slimit]__


If greater than 0, the maximum number of objects on the
input stack. If less than or equal to 0, there is no limit
on the number of objects on the input stack. With no limit,
recursion can continue until virtual memory is
exhausted.


__n[[year]__


The current year. Note that the traditional __troff__
number register __n[[yr]__ is the current year minus
1900.


__Miscellaneous__


__troff__ predefines a single (read/write) string-based
register, __*(.T__, which contains the argument given to
the __-T__ command line option, namely the current output
device (for example, ''latin1'' or ''ascii''). Note
that this is not the same as the (read-only) number register
__n[[.T]__ which is defined to be 1 if __troff__ is
called with the __-T__ command line option, and zero
otherwise. This behaviour is different to UNIX
troff.


Fonts not listed in the DESC file are
automatically mounted on the next available font position
when they are referenced. If a font is to be mounted
explicitly with the __fp__ request on an unused font
position, it should be mounted on the first unused font
position, which can be found in the __n[[.fp]__ register;
although __troff__ does not enforce this strictly, it
will not allow a font to be mounted at a position whose
number is much greater than that of any currently used
position.


Interpolating a string does not hide existing macro
arguments. Thus in a macro, a more efficient way of
doing


__.__''xx'' __\$@__


is


__\*[[__''xx''__]\__


If the font description file contains pairwise kerning
information, characters from that font will be kerned.
Kerning between two characters can be inhibited by placing a
____ between them.


In a string comparison in a condition, characters that
appear at different input levels to the first delimiter
character will not be recognised as the second or third
delimiters. This applies also to the __tl__ request. In a
__w__ escape sequence, a character that appears at a
different input level to the starting delimiter character
will not be recognised as the closing delimiter character.
When decoding a macro argument that is delimited by double
quotes, a character that appears at a different input level
to the starting delimiter character will not be recognised
as the closing delimiter character. The implementation of
__$@__ ensures that the double quotes surrounding an
argument will appear the same input level, which will be
different to the input level of the argument itself. In a
long escape name __]__ will not be recognized as a
closing delimiter except when it occurs at the same input
level as the opening __]__. In compatibility mode, no
attention is paid to the input-level.


There are some new types of condition:


__.if r__''xxx''


True if there is a number register named
''xxx''.


__.if d__''xxx''


True if there is a string, macro, diversion, or request
named ''xxx''.


__.if c__''ch''


True if there is a character ''ch'' available; ''ch''
is either an ASCII character or a special
character ____''xx'' or __[[__''xxx''__]__;
the condition will also be true if ''ch'' has been
defined by the __char__ request.


The __tr__ request can now map characters onto
__~__.


__Warnings__


The warnings that can be given by __troff__ 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 characters. This is enabled by
default.


__number__ 2


Invalid numeric expressions. This is enabled by
default.


__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.


__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 will be 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. a definition is automatically made with a
value of 0. So, in most cases, at most one warning will be
given for use of a particular name.


__tab__ 2048


Inappropriate use of a tab character. Either use of a tab
character where a number was expected, or use of tab
character in an unquoted macro argument.


__right-brace__ 4096


Use of __}__ where a number was expected.


__missing__ 8192


Requests that are missing non-optional
arguments.


__input__ 16384


Illegal input characters.


__escape__ 32768


Unrecognized escape sequences. When an unrecognized escape
sequence is encountered, the escape character is
ignored.


__space__ 65536


Missing space between a request or macro and its argument.
This warning will be 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 will not be invoked. When this warning is given, no
macro is automatically defined. This is enabled by default.
This warning will never occur in compatibility
mode.


__font__ 131072


Non-existent fonts. This is enabled by default.


__ig__ 262144


Illegal escapes in text ignored with the __ig__ request.
These are conditions that are errors when they do not occur
in ignored text.


There are also names that can be used to refer to groups of
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.


__Incompatibilities__


Long names cause some incompatibilities. UNIX troff will
interpret


__.dsabcd__


as defining a string __ab__ with contents __cd__.
Normally, GNU troff will interpret this as a call of a macro
named __dsabcd__. Also UNIX troff will interpret
__*[[__ or __n[[__ as references to a string or number
register called __[[__. In GNU troff, however, this will
normally be interpreted as the start of a long name. In
''compatibility mode'' GNU troff will interpret these
things in the traditional way. In compatibility mode,
however, long names are not recognised. Compatibility mode
can be turned on with the __-C__ command line option, and
turned on or off with the __cp__ request. The number
register __n[[.C]__ is 1 if compatibility mode is on, 0
otherwise.


GNU troff does not allow the use of the escape sequences
__\|^__(space)__'`-_!%c__ in names of strings,
macros, diversions, number registers, fonts or environments;
UNIX troff does. The __A__ escape sequence may be helpful
in avoiding use of these escape sequences in
names.


Fractional pointsizes cause one noteworthy incompatibility.
In UNIX troff the __ps__ request ignores scale indicators
and so


__.ps 10u__


will set the pointsize to 10 points, whereas in GNU troff it
will set the pointsize to 10 scaled points.


In GNU troff there is a fundamental difference between
unformatted, input characters, and formatted, output
characters. Everything that affects how an output character
will be output is stored with the character; once an output
character has been constructed it is unaffected by any
subsequent requests that are executed, including __bd__,
__cs__, __tkf__, __tr__, or __fp__ requests.
Normally output characters are constructed from input
characters at the moment immediately before the character 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 output characters in
any combination. An output character 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
__


will print __\__ in GNU troff; each pair of input
__\__s is turned into one output __\__ and the
resulting output __\__s 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 __\__ is to use the __e__ escape sequence:
this will always print a single instance of the current
escape character, regardless of whether or not it is used in
a diversion; it will also work in both GNU troff and UNIX
troff. If you wish for some reason to store in a diversion
an escape sequence that will be interpreted when the
diversion is reread, you can either use the traditional
__!__ transparent output facility, or, if this is
unsuitable, the new __?__ escape sequence.
!!ENVIRONMENT


__GROFF_TMAC_PATH__


A colon separated list of directories in which to search for
macro files. __troff__ will scan directories given in the
__-M__ option before these, and in standard directories
(current directory if in unsafe mode, home directory,
__/usr/share/groff/site-tmac__,
__/usr/lib/groff/site-tmac__,
__/usr/share/groff/1.17.2/tmac__) after
these.


__GROFF_TYPESETTER__


Default device.


__GROFF_FONT_PATH__


A colon separated list of directories in which to search for
the __dev__''name'' directory. __troff__ will scan
directories given in the __-F__ option before these, and
in standard directories
(__/usr/share/groff/1.17.2/font:/usr/lib/font__) after
these.
!!FILES


__/usr/share/groff/1.17.2/tmac/troffrc__


Initialization file (called before any other macro
package).


__/usr/share/groff/1.17.2/tmac/troffrc-end__


Initialization file (called after any other macro
package).


__/usr/share/groff/1.17.2/tmac/__''name''__.tmac__


__/usr/share/groff/1.17.2/tmac/tmac.__''name''


Macro files


__/usr/share/groff/1.17.2/font/dev__''name''__/DESC__


Device description file for device ''name''.


__/usr/share/groff/1.17.2/font/dev__''name''__/__''F''


Font file for font ''F'' of device
''name''.


Note that __troffrc__ and __troffrc-end__ are neither
searched in the current nor in the home directory by default
for security reasons (even if the __-U__ option is
given). Use the __-M__ command line option or the
__GROFF_TMAC_PATH__ environment variable to add these
directories to the search path if necessary.
!!SEE ALSO


groff(7) -- This is a short but complete reference of
all requests, registers, and escapes.


groff(1), tbl(1), pic(1),
eqn(1), refer(1), soelim(1),
grn(1), grops(1), grodvi(1),
grotty(1), grohtml(1), grolj4(1),
groff_font(5), __groff_out__(5),
groff_char(7)
----
41 pages link to troff(1):
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Last edited on Tuesday, June 4, 2002 12:22:58 am by "perry"
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