2 .\" The above line should force the use of eqn as a preprocessor
6 Last update : 15 May 2003
8 This file is part of groff, the GNU roff type-setting system.
9 It is the source of the man-page groff_diff(7).
11 Copyright (C) 1989, 2001, 2002, 2003 Free Software Foundation, Inc.
12 written by James Clark
14 modified by Werner Lemberg <wl@gnu.org>
15 Bernd Warken <bwarken@mayn.de>
17 Permission is granted to copy, distribute and/or modify this document
18 under the terms of the GNU Free Documentation License, Version 1.1 or
19 any later version published by the Free Software Foundation; with the
20 Invariant Sections being this .ig-section and AUTHORS, with no
21 Front-Cover Texts, and with no Back-Cover Texts.
23 A copy of the Free Documentation License is included as a file called
24 FDL in the main directory of the groff source package.
27 .\" --------------------------------------------------------------------
29 .\" --------------------------------------------------------------------
43 .\" define a string tx for the TeX logo
44 .ie t .ds tx T\h'-.1667m'\v'.224m'E\v'-.224m'\h'-.125m'X
48 .\" --------------------------------------------------------------------
49 .\" start of macro definitions
71 .\" Text \[oq]\f[CB]\*[@arg1]\f[]\[cq]\$*
72 . Text \[oq]\f[B]\*[@arg1]\f[]\[cq]\$*
75 .c A shell command line
78 . IR "shell#" "\h'1m'\f[CB]\$*\f[]\/"
80 .c reference of a request or macro
84 .\" Text \f[CB]\*[@arg1]\f[]\$*
85 . Text \f[B]\*[@arg1]\f[]\$*
90 .c representation of an escape sequence
94 .\" Text \f[CB]\[rs]\*[@arg1]\f[]\$*
95 . Text \f[B]\[rs]\*[@arg1]\&\f[]\$*
99 .\" end of macro definitions
101 .\" from old groff_out.man
108 .\" --------------------------------------------------------------------
110 .\" --------------------------------------------------------------------
112 .TH GROFF_DIFF @MAN7EXT@ "@MDATE@" "Groff Version @VERSION@"
114 groff_diff \- differences between GNU troff and classical troff
117 .\" --------------------------------------------------------------------
119 .\" --------------------------------------------------------------------
121 This manual page describes the language differences between
125 text processing system and the classical
127 formatter of the freely available Unix\~7 of the 1970s, documented in
129 .I Troff User's Manual
134 This inludes the roff language as well as the intermediate output
135 format (troff output).
140 gives pointers to both the classical
147 .\" --------------------------------------------------------------------
149 .\" --------------------------------------------------------------------
151 In this section, all additional features of
153 compared to the classical Unix\~7
155 are described in detail.
158 .\" --------------------------------------------------------------------
160 .\" --------------------------------------------------------------------
162 The names of number registers, fonts, strings/\:macros/\:diversions,
163 special characters (glyphs), and colors can be of any length.
165 In escape sequences, additionally to the classical
167 construction for a two-character name, you can use
169 for a name of arbitrary length.
173 Print the special character (glyph) called
177 .BI \[rs][ "comp1 comp2 .\|.\|." ]
178 Print composite glyph consisting of multiple components.
180 Example: `\[rs][A\~ho]' is capital letter A with ogonek which finally maps
181 to glyph name `u0041_0328'.
185 for details how a glyph name for a composite glyph is constructed, and
186 .BR groff_char (@MAN7EXT@)
187 for list of glyph name components used composite glyph names.
196 is a new syntax equal to
198 i.e., to return to the previous font.
201 .BI \[rs]*[ "xxx arg1 arg2 .\|.\|." ]
212 Interpolate number register
216 .\" --------------------------------------------------------------------
217 .SS "Fractional pointsizes"
218 .\" --------------------------------------------------------------------
230 There is a new scale indicator
232 that has the effect of multiplying by sizescale.
234 Requests and escape sequences in troff interpret arguments that
235 represent a pointsize as being in units of scaled points, but they
236 evaluate each such argument using a default scale indicator of
238 Arguments treated in this way are the argument to the
240 request, the third argument to the
242 request, the second and fourth arguments to the
244 request, the argument to the
246 escape sequence, and those variants of the
248 escape sequence that take a numeric expression as their argument.
251 For example, suppose sizescale is 1000; then a scaled point will be
252 equivalent to a millipoint; the call
256 and so sets the pointsize to 10250 scaled points, which is equal to
262 returns the pointsize in points as decimal fraction.
264 There is also a new number register
266 that returns the pointsize in scaled points.
269 It would make no sense to use the
271 scale indicator in a numeric expression whose default scale indicator
280 Similarly it would make no sense to use a scaling indicator other than
284 in a numeric expression whose default scale indicator was
288 disallows this as well.
291 There is also new scale indicator\~\c
293 which multiplies by the number of units in a scaled point.
299 Be sure not to confuse the
306 .\" --------------------------------------------------------------------
307 .SS "Numeric expressions"
308 .\" --------------------------------------------------------------------
310 Spaces are permitted in a number expression within parentheses.
314 indicates a scale of 100ths of an em.
316 indicates a scale of 65536 units, providing fractions for color
321 For example, 0.5f = 32768u.
343 as the default scaling indicator.
347 is missing, ignore scaling indicators in the evaluation of
351 .\" --------------------------------------------------------------------
352 .SS "New escape sequences"
353 .\" --------------------------------------------------------------------
356 .BI \[rs]A' anything '
361 resp., depending on whether
363 is or is not acceptable as the name of a string, macro, diversion, number
364 register, environment, font, or color.
371 This is useful if you want to lookup user input in some sort of
375 .BI \[rs]B' anything '
380 resp., depending on whether
382 is or is not a valid numeric expression.
394 Normally it is more convenient to use
395 .BI \[rs][ xxx ]\f[R].
398 has the advantage that it is compatible with recent versions of
400 and is available in compatibility mode.
404 This is equivalent to an escape character, but it is not interpreted in
407 For example, strings to start and end superscripting could be defined
413 .Text .ds { \[rs]v'\-.3m'\[rs]s'\[rs]En[.s]*6u/10u'
415 .Text .ds } \[rs]s0\[rs]v'.3m'
421 ensures that these definitions will work even if
423 gets interpreted in copy-mode (for example, by being used in a macro
435 This is the same as the
440 switches back to the previous color (note that
442 won't work; it selects font family `P' instead).
452 switches back to the previous color.
460 Set background color for filled objects drawn with the
461 .BI \[rs]D' .\|.\|. '
464 switches back to the previous color.
468 Typeset the glyph with index
474 Most devices only have glyphs with indices between 0 and 255.
476 If the current font does not contain a glyph with that code,
483 escape sequence can be conveniently used in conjunction with the
490 .Text .char \[rs][phone] \[rs]f(ZD\[rs]N'37'
495 The index of each glyph is given in the fourth column in the font
496 description file after the
500 It is possible to include unnamed glyphs in the font description
501 file by using a name of
505 escape sequence is the only way to use these.
511 Suppressing troff output.
519 are intended for internal use by
525 Disable any ditroff glyphs from being emitted to the device driver,
526 provided that the escape occurs at the outer level (see
533 Enable output of glyphs, provided that the escape occurs at the outer
539 also reset the registers
547 These four registers mark the top left and bottom right hand corners
548 of a box which encompasses all written glyphs.
552 Provided that the escape occurs at the outer level, enable output of
553 glyphs and also write out to stderr the page number and four registers
554 encompassing the glyphs previously written since the last call to
559 Begin a nesting level.
565 This is really an internal mechanism for
567 while producing images.
569 They are generated by running the troff source through
571 to the postscript device and
573 to produce images in PNG format.
577 escape will start a new page if the device is not html (to reduce the
578 possibility of images crossing a page boundary).
585 .BI \[rs]O5[ Pfilename ]
590 Provided that this escape occurs at the outer nesting level, write
594 The position of the image,
596 must be specified and must be one of l, r, c, or i (left, right,
600 will be associated with the production of the next inline image.
604 .BI \[rs]R' name\ \[+-]n '
605 This has the same effect as
609 .BI .nr\ name\ \[+-]n
616 Set the point size to
620 must be exactly two digits.
630 Set the point size to
634 is a numeric expression with a default scale indicator of\~\c
643 Interpolate the contents of the environment variable
648 is interpreted in copy-mode.
656 This is approximately equivalent to
657 .BI \[rs]X'\[rs]*[ xxx ]'\f[R].
658 However the contents of the string or macro
660 are not interpreted; also it is permitted for
662 to have been defined as a macro and thus contain newlines (it is not
663 permitted for the argument to
665 to contain newlines).
667 The inclusion of newlines requires an extension to the UNIX troff
668 output format, and will confuse drivers that do not know about this
672 .BI \[rs]Z' anything '
673 Print anything and then restore the horizontal and vertical position;
675 may not contain tabs or leaders.
679 The name by which the current macro was invoked.
683 request can make a macro have more than one name.
687 In a macro or string, the concatenation of all the arguments separated
692 In a macro or string, the concatenation of all the arguments with each
693 surrounded by double quotes, and separated by spaces.
699 In a macro or string, this gives the
705 Macros and strings can have an unlimited number of arguments.
708 .BI \[rs]? anything \[rs]?
709 When used in a diversion, this will transparently embed
713 is read in copy mode.
715 When the diversion is reread,
719 may not contain newlines; use
721 if you want to embed newlines in a diversion.
725 is also recognised in copy mode and turned into a single internal
726 code; it is this code that terminates
738 .Text \[rs]?\[rs]\[rs]?\[rs]\[rs]\[rs]\[rs]?\[rs]\[rs]\[rs]\[rs]\[rs]\[rs]\[rs]\c
739 .Text \[rs]nx\[rs]\[rs]\[rs]\[rs]?\[rs]\[rs]?\[rs]?
761 This increases the width of the preceding glyph so that the
762 spacing between that glyph and the following glyph will be
763 correct if the following glyph is a roman glyph.
766 . nop For example, if an italic f is immediately followed by a roman
767 . nop right parenthesis, then in many fonts the top right portion of
768 . nop the f will overlap the top left of the right parenthesis
769 . nop producing \f[I]f\f[R])\f[R], which is ugly.
773 . ie \n(.g \f[I]f\/\f[R])\f[R]
774 . el \f[I]f\|\f[R])\f[R]
775 . nop and avoids this problem.
777 It is a good idea to use this escape sequence whenever an italic
778 glyph is immediately followed by a roman glyph without any
783 This modifies the spacing of the following glyph so that the
784 spacing between that glyph and the preceding glyph will
785 correct if the preceding glyph is a roman glyph.
788 . nop For example, inserting
790 . nop between the parenthesis and the f changes
791 . nop \f[R](\f[I]f\f[R] to
792 . ie \n(.g \f[R](\,\f[I]f\f[R].
793 . el \f[R](\^\f[I]f\f[R].
795 It is a good idea to use this escape sequence whenever a roman
796 glyph is immediately followed by an italic glyph without any
803 except that it behaves like a character declared with the
805 request to be transparent for the purposes of end-of-sentence
810 This produces an unbreakable space that stretches like a normal
811 inter-word space when a line is adjusted.
815 This causes the insertion of a zero-width break point.
819 within a word but without insertion of a soft hyphen character.
823 Everything up to and including the next newline is ignored.
825 This is interpreted in copy mode.
831 does not ignore the terminating newline.
834 .\" --------------------------------------------------------------------
836 .\" --------------------------------------------------------------------
842 for number register object named
844 The new name and the old name will be exactly equivalent.
848 is undefined, a warning of type
850 will be generated, and the request will be ignored.
856 for request, string, macro, or diversion object named
859 The new name and the old name will be exactly equivalent (it is
860 similar to a hard rather than a soft link).
864 is undefined, a warning of type
866 will be generated, and the request will be ignored.
876 requests only create a new object if the name of the macro, diversion
877 or string diversion is currently undefined or if it is defined to be a
878 request; normally they modify the value of an existing object.
882 Append to macro indirectly.
886 request below for more information.
892 but compatibility mode is switched off during execution.
894 To be more precise, a `compatibility save' token is inserted at the
895 beginning of the macro addition, and a `compatibility restore' token at
898 As a consequence, the requests
904 can be intermixed freely since the compatibility save/\:restore tokens
905 only affect the macro parts defined by
912 This request `unformats' the diversion
916 and space characters (and some escape sequences) that were formatted
919 will be treated like ordinary input characters when
922 Useful for diversions in conjunction with the
926 It can be also used for gross hacks; for example, this
946 will set register\~\c
950 Note that glyph information (font, font size, etc.) is not preserved;
959 but compatibility mode is switched off during expansion.
961 To be more precise, a `compatibility save' token is inserted at the
962 beginning of the string, and a `compatibility restore' token at the end.
964 As a consequence, the requests
970 can be intermixed freely since the compatibility save/\:restore tokens
971 only affect the (sub)strings defined by
978 Print a backtrace of the input stack on stderr.
982 Set the blank line macro to
984 If there is a blank line macro, it will be invoked when a blank line
985 is encountered instead of the usual troff behaviour.
991 These requests are similar to the
995 requests with the exception that a partially filled line will not
996 become part of the diversion (i.e., the diversion always starts with a
997 new line) but restored after ending the diversion, discarding the
998 partially filled line which possibly comes from the diversion.
1002 Break out of a while loop.
1010 Be sure not to confuse this with the
1020 .BI .cflags\ n\ c1\ c2\|.\|.\|.\&
1024 have properties determined by
1026 which is ORed from the following:
1030 The character ends sentences (initially characters
1032 have this property).
1035 Lines can be broken before the character (initially no characters have
1036 this property); a line will not be broken at a character with this
1037 property unless the characters on each side both have non-zero
1041 Lines can be broken after the character (initially characters
1042 .B \-\[rs][hy]\[rs][em]
1043 have this property); a line will not be broken at a character with
1044 this property unless the characters on each side both have non-zero
1048 The character overlaps horizontally (initially characters
1049 .B \[rs][ul]\[rs][rn]\[rs][ru]\[rs][radicalex]\[rs][sqrtex]
1050 have this property).
1053 The character overlaps vertically (initially character
1058 An end-of-sentence character followed by any number of characters with
1059 this property will be treated as the end of a sentence if followed by
1060 a newline or two spaces; in other words the character is transparent
1061 for the purposes of end-of-sentence recognition; this is the same as
1062 having a zero space factor in \*[tx] (initially characters
1063 .B \[dq]')]*\[rs](dg\[rs](rq
1064 have this property).
1068 .BI .char\ c\ string
1075 needs to be printed,
1077 will be processed in a temporary environment and the result will be
1078 wrapped up into a single object.
1080 Compatibility mode will be turned off and the escape character will be
1087 Any emboldening, constant spacing or track kerning will be applied to
1088 this object rather than to individual glyphs in
1092 A glyph defined by this request can be used just like a normal
1093 glyph provided by the output device.
1095 In particular other characters can be translated to it with the
1097 request; it can be made the leader character by the
1099 request; repeated patterns can be drawn with the character using the
1103 escape sequences; words containing the character can be hyphenated
1106 request is used to give the character a hyphenation code.
1109 There is a special anti-recursion feature: Use of glyph within the
1110 glyph's definition will be handled like normal glyphs not
1114 A glyph definition can be removed with the
1120 Chop the last element off macro, string, or diversion
1122 This is useful for removing the newline from the end of diversions
1123 that are to be interpolated as strings.
1127 Close the stream named
1130 will no longer be an acceptable argument to the
1139 .BI .composite\ glyph1\ glyph2
1146 with more than one component.
1150 Finish the current iteration of a while loop.
1162 is non-zero or missing, enable colors (this is the default), otherwise
1169 is non-zero or missing, enable compatibility mode, otherwise disable
1172 In compatibility mode, long names are not recognised, and the
1173 incompatibilities caused by long names do not arise.
1176 .BI .defcolor\ xxx\ scheme\ color_components
1179 can be one of the following values:
1185 (four components), and
1191 Color components can be given either as a hexadecimal string or as
1192 positive decimal integers in the range 0-65535.
1194 A hexadecimal string contains all color components concatenated; it
1195 must start with either
1199 The former specifies hex values in the range 0-255 (which are
1200 internally multiplied by\~257), the latter in the range 0-65535.
1202 Examples: #FFC0CB (pink), ##ffff0000ffff (magenta).
1204 A new scaling indicator\~\c
1206 has been introduced which multiplies its value by\~65536; this makes
1207 it convenient to specify color components as fractions in the range 0
1215 .Text .defcolor darkgreen rgb 0.1f 0.5f 0.2f
1223 is the default scaling indicator for the
1225 request, thus the above statement is equivalent to
1230 .Text .defcolor darkgreen rgb 0.1 0.5 0.2
1238 (which is device-specific) can't be redefined.
1240 It is possible that the default color for
1248 Define macro indirectly.
1250 The following example
1279 but compatibility mode is switched off during execution.
1281 On entry, the current compatibility mode is saved and restored at exit.
1287 with compatibility mode disabled.
1300 would have the same effect as
1309 except that it would work even if compatibility mode had been enabled.
1311 Note that the previous compatibility mode is restored before any files
1322 but compatibility mode is switched off during expansion.
1324 To be more precise, a `compatibility save' token is inserted at the
1325 beginning of the string, and a `compatibility restore' token at the end.
1329 Save current escape character.
1333 Restore escape character saved with
1335 Without a previous call to
1338 will be the new escape character.
1342 Copy the contents of environment
1344 to the current environment.
1346 No pushing or popping of environments will be done.
1350 Set the current font family to
1352 The current font family is part of the current environment.
1355 is missing, switch back to previous font family.
1357 The value at start-up is `T'.
1359 See the description of the
1361 request for more information on font families.
1364 .BI .fchar\ c\ string
1365 Define fallback glyph
1370 The syntax of this request is the same as the
1372 request; the only difference is that a glyph defined with
1374 hides the glyph with the same name in the current font, whereas a
1377 is checked only if the particular glyph isn't found in the current font.
1379 This test happens before checking special fonts.
1382 .BI .fschar\ f\ c\ string
1383 Define fallback glyph
1390 The syntax of this request is the same as the
1392 request (with an additional argument to specify the font); a glyph
1395 is searched after the list of fonts declared with the
1397 request but before the list of fonts declared with
1401 .BI .fspecial\ f\ s1\ s2\|.\|.\|.\&
1402 When the current font is
1407 will be special, that is, they will searched for glyphs not in
1410 Any fonts specified in the
1412 request will be searched after fonts specified in the
1416 Without argument, reset the list of global special fonts to be empty.
1424 Whenever a font named
1426 is referred to in an
1428 escape sequence, or in the
1444 is missing, or equal to
1448 will not be translated.
1451 .BI .hcode \ c1\ code1\ c2\ code2\|.\|.\|.\&
1452 Set the hyphenation code of character
1460 A hyphenation code must be a single input character (not a special
1461 character) other than a digit or a space.
1463 Initially each lower-case letter \%a-z has a hyphenation code, which is
1464 itself, and each upper-case letter \%A-Z has a hyphenation code which is
1465 the lower-case version of itself.
1473 Set the current hyphenation language to
1475 Hyphenation exceptions specified with the
1477 request and hyphenation patterns specified with the
1479 request are both associated with the current hyphenation language.
1483 request is usually invoked by the
1489 Set the maximum number of consecutive hyphenated lines to\~\c
1493 is negative, there is no maximum.
1495 The default value is\~\-1.
1497 This value is associated with the current environment.
1499 Only lines output from an environment count towards the maximum
1500 associated with that environment.
1502 Hyphens resulting from
1504 are counted; explicit hyphens are not.
1508 Read hyphenation patterns from
1510 this will be searched for in the same way that
1512 is searched for when the
1514 option is specified.
1516 It should have the same format as (simple) \*[tx] patterns files.
1518 More specifically, the following scanning rules are implemented.
1522 A percent sign starts a comment (up to the end of the line) even if
1523 preceded by a backslash.
1526 No support for `digraphs' like
1534 (character code of\~\c
1536 in the range 0-127) are recognized; other use of
1545 checks for the expression
1546 .B \[rs]patterns{.\|.\|.}
1547 (possibly with whitespace before and after the braces).
1549 Everything between the braces is taken as hyphenation patterns.
1555 are not allowed in patterns.
1559 .B \[rs]hyphenation{.\|.\|.}
1560 gives a list of hyphenation exceptions.
1567 For backwards compatibility, if
1569 is missing, the whole file is treated as a list of hyphenation patterns
1570 (only recognizing the
1572 character as the start of a comment).
1578 request to map the encoding used in hyphenation patterns files to
1582 The set of hyphenation patterns is associated with the current language
1589 request is usually invoked by the
1591 file; a second call replaces the old patterns with the new ones.
1597 except that the hyphenation patterns from
1599 are appended to the patterns already loaded in the current language.
1602 .BI .hpfcode\ a\ b\ c\ d\ .\|.\|.
1603 After reading a hyphenation patterns file with the
1607 request, convert all characters with character code\~\c
1609 in the recently read patterns to character code\~\c
1617 Initially, all character codes map to themselves.
1621 must be integers in the range 0 to\~255.
1623 Note that it is even possible to use character codes which are invalid in
1630 .I hyphenation margin
1633 when the current adjustment mode is not\~\c
1635 the line will not be hyphenated if the line is no more than
1639 The default hyphenation margin is\~0.
1641 The default scaling indicator for this request is\~\c
1643 The hyphenation margin is associated with the current environment.
1645 The current hyphenation margin is available in the
1652 .I hyphenation space
1655 when the current adjustment mode is\~\c
1657 don't hyphenate the line if the line can be justified by adding no
1660 extra space to each word space.
1662 The default hyphenation space is\~0.
1664 The default scaling indicator for this request is\~\c
1666 The hyphenation space is associated with the current environment.
1668 The current hyphenation space is available in the
1676 for which a line interrupted with
1678 counts as one input line.
1684 is non-zero or missing, enable pairwise kerning, otherwise disable it.
1687 .BI .length\ xx\ string
1688 Compute the length of
1690 and return it in the number register
1692 (which is not necessarily defined before).
1698 is non-zero or missing, enable line-tabs mode, otherwise disable it
1699 (which is the default).
1701 In line-tabs mode, tab distances are computed relative to the
1702 (current) output line.
1704 Otherwise they are taken relative to the input line.
1706 For example, the following
1713 .Text .ds x a\[rs]t\[rs]c
1714 .Text .ds y b\[rs]t\[rs]c
1733 In line-tabs mode, the same code gives
1741 Line-tabs mode is associated with the current environment; the
1742 read-only number register
1743 .B \\[rs]n[.linetabs]
1744 is set to\~1 if in line-tabs mode, and 0 otherwise.
1752 is searched for in the same directories as macro files for the the
1754 command line option.
1756 If the file name to be included has the form
1762 instead and vice versa.
1768 This is similar to `.if\ 1'.
1774 built-in condition true and the
1776 built-in condition false.
1778 This can be reversed using the
1783 .BI .open\ stream\ filename
1786 for writing and associate the stream named
1797 .BI .opena\ stream\ filename
1802 exists, append to it instead of truncating it.
1808 directly to the intermediate output (subject to copy-mode interpretation);
1811 used at the top level.
1813 An initial double quote in
1815 is stripped off to allow initial blanks.
1819 Print the names and contents of all currently defined number registers
1823 .BI .psbb \ filename
1824 Get the bounding box of a PostScript image
1826 This file must conform to Adobe's Document Structuring Conventions;
1827 the command looks for a
1829 comment to extract the bounding box values.
1831 After a successful call, the coordinates (in PostScript units) of the
1832 lower left and upper right corner can be found in the registers
1840 If some error has occurred, the four registers are set to zero.
1844 This behaves like the
1846 request except that input comes from the standard output of
1851 Print the names and positions of all traps (not including input line
1852 traps and diversion traps) on stderr.
1854 Empty slots in the page trap list are printed as well, because they
1855 can affect the priority of subsequently planted traps.
1859 Set the post-vertical line space to
1861 default scale indicator is\~\c
1864 This value will be added to each line after it has been output.
1866 With no argument, the post-vertical line space is set to its previous
1870 The total vertical line spacing consists of four components:
1874 with a negative value which are applied before the line is output, and
1878 with a positive value which are applied after the line is output.
1881 .BI .rchar\ c1\ c2\|.\|.\|.\&
1882 Remove the definitions of glyphs
1885 This undoes the effect of a
1891 Within a macro, return immediately.
1893 If called with an argument, return twice, namely from the current macro and
1894 from the macro one level higher.
1896 No effect otherwise.
1899 .BI .rfschar\ c1\ c2\|.\|.\|.\&
1900 Remove the font-specific definitions of glyphs
1903 This undoes the effect of a
1911 Right justify the next
1915 Without an argument right justify the next input line.
1917 The number of lines to be right justified is available in the
1921 This implicitly does
1925 request implicitly does
1930 Rename number register
1936 .BI .schar\ c\ string
1937 Define global fallback glyph
1942 The syntax of this request is the same as the
1944 request; a glyph defined with
1946 is searched after the list of fonts declared with the
1948 request but before the mounted special fonts.
1952 Set the soft hyphen character to
1956 is omitted, the soft hyphen character will be set to the default
1958 The soft hyphen character is the glyph which will be inserted when
1959 a word is hyphenated at a line break.
1961 If the soft hyphen character does not exist in the font of the
1962 glyph immediately preceding a potential break point, then the line
1963 will not be broken at that point.
1965 Neither definitions (specified with the
1967 request) nor translations (specified with the
1969 request) are considered when finding the soft hyphen character.
1973 In a macro, shift the arguments by
1975 positions: argument\~\c
1981 will no longer be available.
1985 is missing, arguments will be shifted by\~1.
1987 Shifting by negative amounts is currently undefined.
1990 .BI .sizes\ s1\ s2\|.\|.\|.\|sn\ [0]
1991 This command is similar to the
1997 It sets the available font sizes for the current font to
1999 .IR s2 ,\|.\|.\|.\|,\~ sn
2002 The list of sizes can be terminated by an optional\~\c
2007 can also be a range of sizes
2010 Contrary to the font file command, the list can't extend over more
2014 .BI .special\ s1\ s2\|.\|.\|.\&
2018 are special and will be searched for glyphs not in the current
2021 Without arguments, reset the list of special fonts to be empty.
2024 .BI .spreadwarn\ limit
2027 emit a warning if the additional space inserted for each space between
2028 words in an output line is larger or equal to
2031 A negative value is changed to zero; no argument toggles the warning on
2032 and off without changing
2035 The default scaling indicator is\~\c
2045 .B .spreadwarn\ 0.2m
2046 will cause a warning if
2048 must add 0.2m or more for each interword space in a line.
2050 This request is active only if text is justified to both margins (using
2057 with font position\~\c
2059 A font position can be associated either with a font or with a style.
2061 The current font is the index of a font position and so is also either
2064 When it is a style, the font that is actually used is the font the
2065 name of which is the concatenation of the name of the current family
2066 and the name of the current style.
2068 For example, if the current font is\~1 and font position\~1 is
2069 associated with style\~\c
2071 and the current font family is\~\c
2077 If the current font is not a style, then the current family is ignored.
2086 are applied to a style, then they will instead be applied to the
2087 member of the current family corresponding to that style.
2089 The default family can be set with the
2097 file controls which font positions (if any) are initially associated
2098 with styles rather than fonts.
2101 .BI .substring\ xx\ n1\ [ n2 ]
2102 Replace the string named
2104 with the substring defined by the indices
2108 The first character in the string has index\~0.
2112 is omitted, it is taken to be equal to the string's length.
2118 is negative, it will be counted from the end of the string,
2121 The last character has index\~-1, the character before the last
2122 character has index\~-2, etc.
2125 .BI .tkf\ f\ s1\ n1\ s2\ n2
2126 Enable track kerning for font
2128 When the current font is
2130 the width of every glyph will be increased by an amount between
2134 when the current point size is less than or equal to
2136 the width will be increased by
2138 when it is greater than or equal to
2140 the width will be increased by
2142 when the point size is greater than or equal to
2144 and less than or equal to
2146 the increase in width is a linear function of the point size.
2154 is read in copy mode and written on the standard error, but an initial
2157 is stripped off to allow initial blanks.
2163 but without writing a final newline.
2167 Transparently output the contents of file
2169 Each line is output as if preceded by
2171 however, the lines are not subject to copy-mode interpretation.
2173 If the file does not end with a newline, then a newline will be added.
2175 For example, you can define a macro\~\c
2177 containing the contents of file\~\c
2196 request, the file cannot contain characters such as
2198 that are not legal troff input characters.
2202 This is the same as the
2204 request except that the
2206 request will use the character code (if any) before the character
2239 This is the same as the
2241 request except that the translations do not apply to text that is
2242 transparently throughput into a diversion with
2274 built-in condition false, and the
2276 built-in condition true.
2278 This undoes the effect of the
2284 This request `unformats' the diversion
2288 request, which tries to convert formatted elements of the diversion
2289 back to input tokens as much as possible,
2291 will only handle tabs and spaces between words (usually caused by
2292 spaces or newlines in the input) specially.
2294 The former are treated as if they were input tokens, and the latter
2295 are stretchable again.
2297 Note that the vertical size of lines is not preserved.
2299 Glyph information (font, font size, space width, etc.) is retained.
2301 Useful in conjunction with the
2309 Enable vertical position traps if
2311 is non-zero, disable them otherwise.
2313 Vertical position traps are traps set by the
2321 request are not vertical position traps.
2323 The parameter that controls whether vertical position traps are
2326 Initially vertical position traps are enabled.
2332 is the sum of the numbers associated with each warning that is to be
2333 enabled; all other warnings will be disabled.
2335 The number associated with each warning is listed in
2336 .BR @g@troff (@MAN1EXT@).
2340 will disable all warnings, and
2342 will disable all warnings except that about missing glyphs.
2346 is not given, all warnings will be enabled.
2350 Set the scaling indicator used in warnings to
2363 At startup, it is set to\~\c
2367 .BI .while \ c\ anything
2374 can be any condition acceptable to an
2378 can comprise multiple lines if the first line starts with
2380 and the last line ends with
2389 .BI .write\ stream\ anything
2395 must previously have been the subject of an
2399 is read in copy mode;
2405 .BI .writec\ stream\ anything
2408 but without writing a final newline.
2411 .BI .writem\ stream\ xx
2412 Write the contents of the macro or string
2417 must previously have been the subject of an
2421 is read in copy mode.
2424 .\" --------------------------------------------------------------------
2425 .SS "Extended escape sequences"
2426 .\" --------------------------------------------------------------------
2429 .BI \[rs]D' .\|.\|. '
2430 All drawing commands of groff's intermediate output are accepted.
2433 .B "Drawing Commands"
2434 below for more information.
2437 .\" --------------------------------------------------------------------
2438 .SS "Extended requests"
2439 .\" --------------------------------------------------------------------
2443 When used in a diversion, this will embed in the diversion an object
2444 which, when reread, will cause the contents of
2446 to be transparently copied through to the output.
2448 In UNIX troff, the contents of
2450 is immediately copied through to the output regardless of whether
2451 there is a current diversion; this behaviour is so anomalous that it
2452 must be considered a bug.
2458 is not a number, this will switch to a named environment called
2460 The environment should be popped with a matching
2462 request without any arguments, just as for numbered environments.
2464 There is no limit on the number of named environments; they will be
2465 created the first time that they are referenced.
2469 When two arguments are given to the
2471 request, the second argument gives the
2472 .IR "sentence space size" .
2473 If the second argument is not given, the sentence space size
2474 will be the same as the word space size.
2476 Like the word space size, the sentence space is in units of
2477 one twelfth of the spacewidth parameter for the current font.
2479 Initially both the word space size and the sentence
2482 Contrary to UNIX troff, GNU troff handles this request in nroff mode
2483 also; a given value is then rounded down to the nearest multiple
2486 The sentence space size is used in two circumstances.
2488 If the end of a sentence occurs at the end of a line in fill mode,
2489 then both an inter-word space and a sentence space will be added; if
2490 two spaces follow the end of a sentence in the middle of a line, then
2491 the second space will be a sentence space.
2493 Note that the behaviour of UNIX troff will be exactly that exhibited
2494 by GNU troff if a second argument is never given to the
2498 In GNU troff, as in UNIX troff, you should always follow a sentence
2499 with either a newline or two spaces.
2502 .BI .ta\ n1\ n2\|.\|.\|.nn \ T\ r1\ r2\|.\|.\|.\|rn
2503 Set tabs at positions
2505 .IR n2 ,\|.\|.\|.\|,
2507 and then set tabs at
2509 .IR nn + r2 ,\|.\|.\|.\|,
2513 .IR nn + rn + r2 ,\|.\|.\|.\|,
2526 will set tabs every half an inch.
2530 .\" --------------------------------------------------------------------
2531 .SS "New number registers"
2532 .\" --------------------------------------------------------------------
2534 The following read-only registers are available:
2538 1\~if compatibility mode is in effect, 0\~otherwise.
2542 The depth of the last glyph added to the current environment.
2544 It is positive if the glyph extends below the baseline.
2548 The number of lines remaining to be centered, as set by the
2554 The height of the last glyph added to the current environment.
2556 It is positive if the glyph extends above the baseline.
2560 1\~if colors are enabled, 0\~otherwise.
2564 The skew of the last glyph added to the current environment.
2568 of a glyph is how far to the right of the center of a glyph
2569 the center of an accent over that glyph should be placed.
2573 The name or number of the current environment.
2575 This is a string-valued register.
2579 The current font family.
2581 This is a string-valued register.
2585 The current (internal) real font name.
2587 This is a string-valued register.
2589 If the current font is a style, the value of
2591 is the proper concatenation of family and style name.
2595 The number of the next free font position.
2601 Macros should use this to determine whether they are running under GNU
2606 The current height of the font as set with
2611 The current hyphenation language as set by the
2617 The number of immediately preceding consecutive hyphenated lines.
2621 The maximum allowed number of consecutive hyphenated lines, as set by
2628 The current hyphenation flags (as set by the
2634 The current hyphenation margin (as set by the
2640 The current hyphenation space (as set by the
2646 The indent that applies to the current output line.
2650 Set to a positive value if last output line is interrupted (i.e., if
2656 1\~if pairwise kerning is enabled, 0\~otherwise.
2660 The current ligature mode (as set by the
2665 .B \[rs]n[.linetabs]
2666 The current line-tabs mode (as set by the
2672 The line length that applies to the current output line.
2676 The title length as set by the
2682 The amount of space that was needed in the last
2684 request that caused a trap to be sprung.
2686 Useful in conjunction with the
2692 1\~if no-space mode is active, 0\~otherwise.
2696 1\~during a page ejection caused by the
2698 request, 0\~otherwise.
2702 The number of the next page, either the value set by a
2704 request, or the number of the current page plus\~1.
2708 The current pointsize in scaled points.
2712 The last-requested pointsize in scaled points.
2716 The current post-vertical line space as set with the
2722 The number of lines to be right-justified as set by the
2728 The slant of the current font as set with
2733 The last requested pointsize in points as a decimal fraction.
2735 This is a string-valued register.
2741 These give the values of the parameters set by the first and second
2748 A string representation of the current tab settings suitable for use
2749 as an argument to the
2755 The amount of vertical space truncated by the most recently sprung
2756 vertical position trap, or, if the trap was sprung by a
2758 request, minus the amount of vertical motion produced by the
2762 In other words, at the point a trap is sprung, it represents the
2763 difference of what the vertical position would have been but for the
2764 trap, and what the vertical position actually is.
2766 Useful in conjunction with the
2772 1\~if vertical position traps are enabled, 0\~otherwise.
2776 The sum of the numbers associated with each of the currently enabled
2779 The number associated with each warning is listed in
2780 .BR @g@troff (@MAN1EXT@).
2784 The major version number.
2786 For example, if the version number is 1.03, then
2792 The minor version number.
2794 For example, if the version number is 1.03, then
2800 The revision number of groff.
2810 These four registers are set by the
2812 request and contain the bounding box values (in PostScript units) of a
2813 given PostScript image.
2816 The following read/write registers are set by the
2828 registers, but take account of the heights and depths of glyphs.
2832 The amount of horizontal space (possibly negative) that should be
2833 added to the last glyph before a subscript.
2837 How far to right of the center of the last glyph in the
2839 argument, the center of an accent from a roman font should be placed
2843 Other available read/write number registers are:
2847 The current input line number.
2849 is a read-only alias to this register.
2853 The number of hours past midnight.
2855 Initialized at start-up.
2859 The current horizontal position at input line.
2863 The number of minutes after the hour.
2865 Initialized at start-up.
2869 The number of seconds after the minute.
2871 Initialized at start-up.
2875 The return value of the system() function executed by the last
2881 If greater than\~0, the maximum number of objects on the input stack.
2883 If less than or equal to\~0, there is no limit on the number of
2884 objects on the input stack.
2886 With no limit, recursion can continue until virtual memory is
2893 Note that the traditional
2897 is the current year minus 1900.
2900 .\" --------------------------------------------------------------------
2902 .\" --------------------------------------------------------------------
2905 predefines a single (read/write) string-based register,
2907 which contains the argument given to the
2909 command line option, namely the current output device (for example,
2913 Note that this is not the same as the (read-only) number register
2915 which is defined to be\~1 if
2919 command line option, and zero otherwise.
2921 This behaviour is different to UNIX troff.
2924 Fonts not listed in the
2926 file are automatically mounted on the next available font position
2927 when they are referenced.
2929 If a font is to be mounted explicitly with the
2931 request on an unused font position, it should be mounted on the first
2932 unused font position, which can be found in the
2936 does not enforce this strictly, it will not allow a font to be mounted
2937 at a position whose number is much greater than that of any currently
2941 Interpolating a string does not hide existing macro arguments.
2943 Thus in a macro, a more efficient way of doing
2946 .BI . xx\ \[rs]\[rs]$@
2951 .BI \[rs]\[rs]*[ xx ]\[rs]\[rs]
2954 If the font description file contains pairwise kerning information,
2955 glyphs from that font will be kerned.
2957 Kerning between two glyphs can be inhibited by placing a
2962 In a string comparison in a condition, characters that appear at
2963 different input levels to the first delimiter character will not be
2964 recognised as the second or third delimiters.
2966 This applies also to the
2972 escape sequence, a character that appears at a different input level
2973 to the starting delimiter character will not be recognised as the
2974 closing delimiter character.
2976 The same is true for
2988 When decoding a macro or string argument that is delimited by double
2989 quotes, a character that appears at a different input level to the starting
2990 delimiter character will not be recognised as the closing delimiter
2993 The implementation of
2995 ensures that the double quotes surrounding an argument will appear the
2996 same input level, which will be different to the input level of the
2999 In a long escape name
3001 will not be recognized as a closing delimiter except when it occurs at
3002 the same input level as the opening
3005 In compatibility mode, no attention is paid to the input-level.
3008 There are some new types of condition:
3012 True if there is a number register named
3017 True if there is a string, macro, diversion, or request named
3022 True if there is a color named
3027 True if there is a glyph
3033 character or a glyph (special character)
3036 .BI \[rs][ xxx ]\f[R];
3037 the condition will also be true if
3039 has been defined by the
3046 request can now map characters onto
3050 It is now possible to have whitespace between the first and second dot
3051 (or the name of the ending macro) to end a macro definition.
3060 .Text . nop Hello, I'm `foo'.
3061 .Text . nop I will now define `bar'.
3063 .Text . nop Hello, I'm `bar'.
3072 .\" --------------------------------------------------------------------
3073 .SH "INTERMEDIATE OUTPUT FORMAT"
3074 .\" --------------------------------------------------------------------
3076 This section describes the format output by GNU troff.
3078 The output format used by GNU troff is very similar to that used
3079 by Unix device-independent troff.
3081 Only the differences are documented here.
3084 .\" --------------------------------------------------------------------
3086 .\" --------------------------------------------------------------------
3090 command is in scaled points (units of
3094 is the argument to the
3096 command in the DESC file).
3100 command is also in scaled points.
3103 .\" --------------------------------------------------------------------
3105 .\" --------------------------------------------------------------------
3109 Print glyph with index\~\c
3111 (a non-negative integer) of the current font.
3116 line is present in the DESC file, troff will use the following two
3122 is any sequence of characters terminated by a space or a newline (to
3123 be more precise, it is a sequence of glyphs which are accessed with
3124 the corresponding characters); the first character should be printed at
3125 the current position, the current horizontal position should be increased
3126 by the width of the first character, and so on for each character.
3128 The width of the glyph is that given in the font file,
3129 appropriately scaled for the current point size, and rounded so that
3130 it is a multiple of the horizontal resolution.
3132 Special characters cannot be printed using this command.
3138 command except that after printing each character, the current
3139 horizontal position is increased by the sum of the width of that
3144 Note that single characters can have the eighth bit set, as can the
3145 names of fonts and special characters.
3148 The names of glyphs and fonts can be of arbitrary length; drivers
3149 should not assume that they will be only two characters long.
3152 When a glyph is to be printed, that glyph will always be
3153 in the current font.
3155 Unlike device-independent troff, it is not necessary for drivers to
3156 search special fonts to find a glyph.
3159 For color support, some new commands have been added:
3162 .Text \f[B]mc \f[I]cyan magenta yellow\f[R]
3166 .Text \f[B]mg \f[I]gray\f[R]
3168 .Text \f[B]mk \f[I]cyan magenta yellow black\f[R]
3170 .Text \f[B]mr \f[I]red green blue\f[R]
3171 Set the color components of the current drawing color, using various
3175 resets the drawing color to the default value.
3177 The arguments are integers in the range 0 to 65536.
3182 device control command has been extended.
3185 .Text \f[B]x u \f[I]n\f[R]
3188 is\~1, start underlining of spaces.
3192 is\~0, stop underlining of spaces.
3194 This is needed for the
3196 request in nroff mode and is ignored otherwise.
3199 .\" --------------------------------------------------------------------
3200 .SS "Drawing Commands"
3201 .\" --------------------------------------------------------------------
3205 drawing command has been extended.
3207 These extensions will not be used by GNU pic if the
3212 .Text \f[B]Df \f[I]n\f[R]\*[ic]\[rs]n
3213 Set the shade of gray to be used for filling solid objects to
3216 must be an integer between 0 and 1000, where 0 corresponds solid white
3217 and 1000 to solid black, and values in between correspond to
3218 intermediate shades of gray.
3220 This applies only to solid circles, solid ellipses and solid
3223 By default, a level of 1000 will be used.
3225 Whatever color a solid object has, it should completely obscure
3226 everything beneath it.
3228 A value greater than 1000 or less than 0 can also be used: this means
3229 fill with the shade of gray that is currently being used for lines and
3232 Normally this will be black, but some drivers may provide a way of
3237 .BI \[rs]D'f .\|.\|. '
3238 command shouldn't be used since its argument is always rounded to an
3239 integer multiple of the horizontal resolution which can lead to
3243 .Text \f[B]DC \f[I]d\f[R]\*[ic]\[rs]n
3244 Draw a solid circle with a diameter of
3246 with the leftmost point at the current position.
3249 .Text \f[B]DE \f[I]dx dy\f[R]\*[ic]\[rs]n
3250 Draw a solid ellipse with a horizontal diameter of
3252 and a vertical diameter of
3254 with the leftmost point at the current position.
3260 .Text \f[B]Dp\f[R] $dx sub 1$ $dy sub 1$ $dx sub 2$ $dy sub 2$ $...$ $dx sub n$ $dy sub n$\[rs]n
3261 Draw a polygon with, for $i = 1 ,..., n+1$, the
3263 vertex at the current position
3265 $+ sum from j=1 to i-1 ( dx sub j , dy sub j )$.
3267 At the moment, GNU pic only uses this command to generate triangles
3271 .Text \f[B]DP\f[R] $dx sub 1$ $dy sub 1$ $dx sub 2$ $dy sub 2$ $...$ $dx sub n$ $dy sub n$\[rs]n
3275 but draw a solid rather than outlined polygon.
3278 .Text \f[B]Dt \f[I]n\f[R]\*[ic]\[rs]n
3279 Set the current line thickness to
3283 Traditionally Unix troff drivers use a line thickness proportional to
3284 the current point size; drivers should continue to do this if no
3286 command has been given, or if a
3288 command has been given with a negative value of
3292 selects the smallest available line thickness.
3295 A difficulty arises in how the current position should be changed after
3296 the execution of these commands.
3298 This is not of great importance since the code generated by GNU pic
3299 does not depend on this.
3301 Given a drawing command of the form
3303 \f[B]\[rs]D\[fm]\f[I]c\f[R] $x sub 1$ $y sub 1$ $x sub 2$ $y sub 2$ $...$ $x sub n$ $y sub n$\[fm]
3315 Unix troff will treat each of the $x sub i$ as a horizontal quantity,
3316 and each of the $y sub i$ as a vertical quantity and will assume that
3317 the width of the drawn object is $sum from i=1 to n x sub i$,
3318 and that the height is $sum from i=1 to n y sub i$.
3320 (The assumption about the height can be seen by examining the
3324 registers after using such a
3326 command in a \[rs]w escape sequence).
3328 This rule also holds for all the original drawing commands with the
3331 For the sake of compatibility GNU troff also follows this rule, even
3332 though it produces an ugly result in the case of the
3336 and, to a lesser extent,
3340 Thus after executing a
3344 \f[B]D\f[I]c\f[R] $x sub 1$ $y sub 1$ $x sub 2$ $y sub 2$ $...$ \c
3345 $x sub n$ $y sub n$\[rs]n
3348 the current position should be increased by
3350 $( sum from i=1 to n x sub i , sum from i=1 to n y sub i )$.
3353 Another set of extensions is
3356 .Text \f[B]DFc \f[I]cyan magenta yellow\f[R]\*[ic]\[rs]n
3358 .Text \f[B]DFd\f[R]\*[ic]\[rs]n
3360 .Text \f[B]DFg \f[I]gray\f[R]\*[ic]\[rs]n
3362 .Text \f[B]DFk \f[I]cyan magenta yellow black\f[R]\*[ic]\[rs]n
3364 .Text \f[B]DFr \f[I]red green blue\f[R]\*[ic]\[rs]n
3365 Set the color components of the filling color similar to the
3370 The current position isn't changed by those colour commands (contrary to
3374 .\" --------------------------------------------------------------------
3375 .SS "Device Control Commands"
3376 .\" --------------------------------------------------------------------
3378 There is a continuation convention which permits the argument to the
3380 command to contain newlines: when outputting the argument to the
3382 command, GNU troff will follow each newline in the argument with a
3384 character (as usual, it will terminate the entire argument with a
3385 newline); thus if the line after the line containing the
3389 then the newline ending the line containing the
3391 command should be treated as part of the argument to the
3395 should be ignored, and the part of the line following the
3397 should be treated like the part of the line following the
3402 The first three output commands are guaranteed to be:
3411 .\" --------------------------------------------------------------------
3412 .SH INCOMPATIBILITIES
3413 .\" --------------------------------------------------------------------
3415 In spite of the many extensions, groff has retained compatibility to
3416 classical troff to a large degree.
3418 For the cases where the extensions lead to collisions, a special
3419 compatibility mode with the restricted, old functionality was created
3423 .\" --------------------------------------------------------------------
3424 .SS "Groff Language"
3425 .\" --------------------------------------------------------------------
3429 .B compatibility mode
3430 that allows to process roff code written for classical
3432 or for other implementations of roff in a consistent way.
3435 Compatibility mode can be turned on with the
3437 command line option, and turned on or off with the
3443 is\~1 if compatibility mode is on, 0\~otherwise.
3446 This became necessary because the GNU concept for long names causes
3447 some incompatibilities.
3454 as defining a string
3460 mode, this will be considered as a call of a macro named
3470 as references to a string or number register called
3474 takes this as the start of a long name.
3478 .IR "compatibility mode" ,
3479 groff interprets these things in the traditional way; so long
3480 names are not recognized.
3483 On the other hand, groff in
3485 does not allow to use the single-character escapes
3514 (character c) in names of strings, macros, diversions, number
3515 registers, fonts or environments, whereas
3522 escape sequence can be helpful in avoiding these escape sequences in
3526 Fractional pointsizes cause one noteworthy incompatibility.
3533 request ignores scale indicators and so
3540 will set the pointsize to 10\~points, whereas in groff native mode the
3541 pointsize will be set to 10\~scaled points.
3546 mode, there is a fundamental difference between unformatted input
3547 characters, and formatted output characters (glyphs).
3549 Everything that affects how a glyph will be output is
3550 stored with the glyph; once a glyph has been
3551 constructed it is unaffected by any subsequent requests that are
3552 executed, including the
3562 Normally glyphs are constructed from input characters at
3563 the moment immediately before the glyph is added to the current
3566 Macros, diversions and strings are all, in fact, the same type of
3567 object; they contain lists of input characters and glyphs
3571 Special characters can be both; before being added to the output, they
3572 act as input entities, afterwards they denote glyphs.
3575 A glyph does not behave like an input character for the
3576 purposes of macro processing; it does not inherit any of the special
3577 properties that the input character from which it was constructed
3580 The following example will make things clearer.
3587 .Text \[rs]\[rs]\[rs]\[rs]
3598 this will be printed as
3600 So each pair of input backslashes
3602 is turned into a single output backslash glyph
3604 and the resulting output backslashes are not interpreted as escape
3605 characters when they are reread.
3609 would interpret them as escape characters when they were reread and
3610 would end up printing a single backslash
3614 In GNU, the correct way to get a printable version of the backslash
3619 escape sequence, but classical troff does not provide a clean feature
3620 for getting a non-syntactical backslash.
3622 A close method is the printable version of the current escape
3625 escape sequence; this works if the current escape character is not
3628 It works in both GNU mode and compatibility mode, while dirty tricks
3629 like specifying a sequence of multiple backslashes do not work
3630 reliably; for the different handling in diversions, macro definitions,
3631 or text mode quickly leads to a confusion about the necessary number of
3635 To store an escape sequence in a diversion that will be interpreted
3636 when the diversion is reread, either the traditional
3638 transparent output facility or the
3641 escape sequence can be used.
3644 .\" --------------------------------------------------------------------
3645 .SS "Intermediate Output"
3646 .\" --------------------------------------------------------------------
3648 The groff intermediate output format is in a state of evolution.
3650 So far it has some incompatibilities, but it is intended to establish
3651 a full compatibility to the classical troff output format.
3653 Actually the following incompatibilities exist:
3656 The positioning after the drawing of the polygons conflicts with the
3657 classical definition.
3660 The intermediate output cannot be rescaled to other devices as
3661 classical "device-independent" troff did.
3664 .\" --------------------------------------------------------------------
3666 .\" --------------------------------------------------------------------
3668 Copyright (C) 1989, 2001, 2002, 2003 Free Software Foundation, Inc.
3671 This document is distributed under the terms of the FDL (GNU Free
3672 Documentation License) version 1.1 or later.
3674 You should have received a copy of the FDL on your system, it is also
3675 available on-line at the
3676 .URL http://\:www.gnu.org/\:copyleft/\:fdl.html "GNU copyleft site" .
3678 This document was written by James Clark, with modifications by
3679 .MTO wl@gnu.org "Werner Lemberg"
3681 .MTO bwarken@mayn.de "Bernd Warken" .
3684 This document is part of
3686 the GNU roff distribution.
3688 Formerly, the contents of this document was kept in the manual
3690 .BR @g@troff (@MAN1EXT@).
3691 Only the parts dealing with the language aspects of the different
3693 systems were carried over into this document.
3697 command line options and warnings are still documented in
3698 .BR @g@troff (@MAN1EXT@).
3700 .\" --------------------------------------------------------------------
3702 .\" --------------------------------------------------------------------
3709 presents all groff documentation within a single document.
3712 .BR groff (@MAN1EXT@)
3713 A list of all documentation around
3717 .BR groff (@MAN7EXT@)
3718 A description of the
3720 language, including a short, but complete reference of all predefined
3721 requests, registers, and escapes of plain
3723 From the command line, this is called using
3726 .ShellCommand man\~7\~groff
3729 .BR roff (@MAN7EXT@)
3732 systems, including pointers to further historical documentation.
3737 .I Nroff/\:Troff User's Manual
3740 of 1976 in the revision of
3743 .URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr/\:54.ps.gz \
3744 "classical troff documentation" .
3747 .\" --------------------------------------------------------------------
3749 .\" --------------------------------------------------------------------
3751 .\" Local Variables: