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GROFF_OUT(5)                                                                                    GROFF_OUT(5)



NAME
       groff_out - groff intermediate output format

DESCRIPTION
       This  manual  page describes the intermediate output format of the GNU roff(7) text processing system
       groff(1).  This output is produced by a run of the GNU troff(1) program.   It  contains  already  all
       device-specific information, but it is not yet fed into a device postprocessor program.

       As the GNU roff processor groff(1) is a wrapper program around troff that automatically calls a post-processor, postprocessor,
       processor, this output does not show up normally.  This is why it is called intermediate  within  the
       groff system.  The groff program provides the option -Z to inhibit postprocessing, such that the pro-duced produced
       duced intermediate output is sent to standard output just like calling troff manually.

       In this document, the term troff output describes what is output by  the  GNU  troff  program,  while
       intermediate  output  refers to the language that is accepted by the parser that prepares this output
       for the postprocessors.  This parser is smarter on whitespace and implements  obsolete  elements  for
       compatibility,  otherwise  both  formats  are  the  same.   Both  formats can be viewed directly with
       gxditview(1).

       The main purpose of the intermediate output concept is to facilitate the development  of  postproces-sors postprocessors
       sors  by providing a common programming interface for all devices.  It has a language of its own that
       is completely different from the groff(7) language.  While the groff language is  a  high-level  pro-gramming programming
       gramming language for text processing, the intermediate output language is a kind of low-level assem-bler assembler
       bler language by specifying all positions on the page for writing and drawing.

       The pre-groff roff versions are denoted as classical troff.   The  intermediate  output  produced  by
       groff  is  fairly  readable,  while  classical troff output was hard to understand because of strange
       habits that are still supported, but not used any longer by GNU troff.

LANGUAGE CONCEPTS
       During the run of troff, the roff input is cracked down to the information on what has to be  printed
       at  what  position  on the intended device.  So the language of the intermediate output format can be
       quite small.  Its only elements are commands with or without arguments.  In this document,  the  term
       "command" always refers to the intermediate output language, never to the roff language used for doc-ument document
       ument formatting.  There are commands for positioning and text writing, for drawing, and  for  device
       controlling.

   Separation
       Classical  troff output had strange requirements on whitespace.  The groff output parser, however, is
       smart about whitespace by making it maximally optional.  The whitespace characters,  i.e.,  the  tab,
       space,  and  newline characters, always have a syntactical meaning.  They are never printable because
       spacing within the output is always done by positioning commands.

       Any sequence of space or tab characters is treated as a single syntactical space.  It separates  com-mands commands
       mands  and arguments, but is only required when there would occur a clashing between the command code
       and the arguments without the space.  Most often, this happens when variable  length  command  names,
       arguments,  argument  lists,  or  command  clusters meet.  Commands and arguments with a known, fixed
       length need not be separated by syntactical space.

       A line break is a syntactical element, too.  Every command argument can be followed by whitespace,  a
       comment,  or  a  newline  character.  Thus a syntactical line break is defined to consist of optional
       syntactical space that is optionally followed by a comment, and a newline character.

       The normal commands, those for positioning and text, consist of a single letter taking a fixed number
       of arguments.  For historical reasons, the parser allows to stack such commands on the same line, but
       fortunately, in groff intermediate output, every command with at least one argument is followed by  a
       line break, thus providing excellent readability.

       The  other commands -- those for drawing and device controlling -- have a more complicated structure;
       some recognize long command names, and some take a variable number of arguments.  So all D and x com-mands commands
       mands were designed to request a syntactical line break after their last argument.  Only one command,
       `x X' has an argument that can stretch over several lines, all other commands must have all of  their
       arguments on the same line as the command, i.e., the arguments may not be splitted by a line break.

       Empty lines, i.e., lines containing only space and/or a comment, can occur everywhere.  They are just
       ignored.

   Argument Units
       Some commands take integer arguments that are assumed to represent values in a measurement unit,  but
       the  letter  for  the corresponding scale indicator is not written with the output command arguments;
       see groff(7) and the groff info file for more on this topic.  Most commands assume the scale  indica-tor indicator
       tor  u,  the basic unit of the device, some use z, the scaled point unit of the device, while others,
       such as the color commands expect plain integers.  Note that these scale indicators are  relative  to
       the  chosen  device.   They  are  defined  by the parameters specified in the device's DESC file; see
       groff_font(5).

       Note that single characters can have the eighth bit set, as can the names of fonts and special  char-acters. characters.
       acters.   The  names  of  characters and fonts can be of arbitrary length.  A character that is to be
       printed will always be in the current font.

       A string argument is always terminated by the next whitespace character (space, tab, or newline);  an
       embedded  # character is regarded as part of the argument, not as the beginning of a comment command.
       An integer argument is already terminated by the next non-digit character, which then is regarded  as
       the first character of the next argument or command.

   Document Parts
       A correct intermediate output document consists of two parts, the prologue and the body.

       The  task  of the prologue is to set the general device parameters using three exactly specified com-mands. commands.
       mands.  The groff prologue is guaranteed to consist of the following three lines (in that order):

              x T device
              x res n h v
              x init

       with the arguments set as outlined in the section Device Control Commands.  But the  parser  for  the
       intermediate output format is able to swallow additional whitespace and comments as well.

       The  body  is  the main section for processing the document data.  Syntactically, it is a sequence of
       any commands different from the ones used in the prologue.  Processing is terminated as soon  as  the
       first  x stop  command is encountered; the last line of any groff intermediate output always contains
       such a command.

       Semantically, the body is page oriented.  A new page is started by a p command.   Positioning,  writ-ing, writing,
       ing,  and  drawing  commands are always done within the current page, so they cannot occur before the
       first p command.  Absolute positioning (by the H and V commands) is  done  relative  to  the  current
       page, all other positioning is done relative to the current location within this page.

COMMAND REFERENCE
       This  section describes all intermediate output commands, the classical commands as well as the groff
       extensions.

   Comment Command
       #anything<end_of_line>
              A comment.  Ignore any characters from the # character up to the next newline character.

       This command is the only possibility for commenting in the intermediate output.  Each comment can  be
       preceded by arbitrary syntactical space; every command can be terminated by a comment.

   Simple Commands
       The  commands in this subsection have a command code consisting of a single character, taking a fixed
       number of arguments.  Most of them are commands for positioning and text writing.  These commands are
       smart about whitespace.  Optionally, syntactical space can be inserted before, after, and between the
       command letter and its arguments.  All of these commands are stackable, i.e., they can be preceded by
       other simple commands or followed by arbitrary other commands on the same line.  A separating syntac-tical syntactical
       tical space is only necessary when two integer arguments would clash or  if  the  preceding  argument
       ends with a string argument.

       C xxx<white_space>
              Print  a  special  groff character named xxx.  The trailing syntactical space or line break is
              necessary to allow character names of arbitrary length.  The character is printed at the  cur-rent current
              rent  print  position; the character's size is read from the font file.  The print position is
              not changed.

       c c    Print character c at the current print position; the character's size is read  from  the  font
              file.  The print position is not changed.

       f n    Set font to font number n (a non-negative integer).

       H n    Move right to the absolute vertical position n (a non-negative integer in basic units u) rela-tive relative
              tive to left edge of current page.

       h n    Move n (a non-negative integer) basic units u horizontally to the right.   [CSTR  #54]  allows
              negative values for n also, but groff doesn't use this.

       m color_scheme [component ...]
              Set  the  color for text (glyphs), line drawing, and the outline of graphic objects using dif-ferent different
              ferent color schemes; the analoguous command for the filling color of graphic objects  is  DF.
              The  color  components  are specified as integer arguments between 0 and 65536.  The number of
              color components and their meaning vary for the different color schemes.  These  commands  are
              generated  by the groff escape sequence \m.  No position changing.  These commands are a groff
              extension.

              mc cyan magenta yellow
                     Set color using the CMY color scheme, having the 3 color components cyan, magenta,  and
                     yellow.

              md     Set color to the default color value (black in most cases).  No component arguments.

              mg gray
                     Set  color to the shade of gray given by the argument, an integer between 0 (black) and
                     65536 (white).

              mk cyan magenta yellow black
                     Set color using the CMYK color scheme, having the 4  color  components  cyan,  magenta,
                     yellow, and black.

              mr red green blue
                     Set  color  using  the  RGB color scheme, having the 3 color components red, green, and
                     blue.

       N n    Print character with index n (an integer, normally non-negative) of  the  current  font.   The
              print  position is not changed.  If -T html is used, negative values are emitted also to indi-cate indicate
              cate an unbreakable space with given width.  For example, N  -193  represents  an  unbreakable
              space which has a width of 193u.  This command is a groff extension.

       n b a  Inform  the device about a line break, but no positioning is done by this command.  In classi-cal classical
              cal troff, the integer arguments b and a informed about the space before and after the current
              line  to  make  the intermediate output more human readable without performing any action.  In
              groff, they are just ignored, but they must be provided for compatibility reasons.

       p n    Begin a new page in the outprint.  The page number is set to n.  This page is completely inde-pendent independent
              pendent  of  pages  formerly  processed even if those have the same page number.  The vertical
              position on the outprint is automatically set to 0.  All positioning, writing, and drawing  is
              always done relative to a page, so a p command must be issued before any of these commands.

       s n    Set  point  size  to  n scaled points (this is unit z in GNU troff).  Classical troff used the
              unit points (p) instead; see section COMPATIBILITY.

       t xxx<white_space>
       t xxx dummy_arg<white_space>
              Print a word, i.e., a sequence of characters xxx terminated by a space  character  or  a  line
              break;  an  optional second integer argument is ignored (this allows the formatter to generate
              an even number of arguments).  The first character should be printed at the current  position,
              the  current horizontal position should then be increased by the width of the first character,
              and so on for each character.  The widths of the characters  are  read  from  the  font  file,
              scaled  for  the  current  point size, and rounded to a multiple of the horizontal resolution.
              Special characters cannot be printed using this command (use the C command for  named  charac-ters). characters).
              ters).   This  command  is a groff extension; it is only used for devices whose DESC file con-tains contains
              tains the tcommand keyword; see groff_font(5).

       u n xxx<white_space>
              Print word with track kerning.  This is the same as the t command except that  after  printing
              each  character,  the current horizontal position is increased by the sum of the width of that
              character and n (an integer in basic units u).  This command is a groff extension; it is  only
              used for devices whose DESC file contains the tcommand keyword; see groff_font(5).

       V n    Move  down to the absolute vertical position n (a non-negative integer in basic units u) rela-tive relative
              tive to upper edge of current page.

       v n    Move n basic units u down (n is a non-negative integer).  [CSTR #54]  allows  negative  values
              for n also, but groff doesn't use this.

       w      Informs  about a paddable whitespace to increase readability.  The spacing itself must be per-formed performed
              formed explicitly by a move command.

   Graphics Commands
       Each graphics or drawing command in the intermediate output starts with the letter D followed by  one
       or  two characters that specify a subcommand; this is followed by a fixed or variable number of inte-ger integer
       ger arguments that are separated by a single space character.  A D command may  not  be  followed  by
       another command on the same line (apart from a comment), so each D command is terminated by a syntac-tical syntactical
       tical line break.

       troff output follows the classical spacing rules (no space between command and subcommand, all  argu-ments arguments
       ments  are  preceded  by  a single space character), but the parser allows optional space between the
       command letters and makes the space before the first argument optional.  As usual, each space can  be
       any sequence of tab and space characters.

       Some graphics commands can take a variable number of arguments.  In this case, they are integers rep-resenting representing
       resenting a size measured in basic units u.  The arguments called h1, h2, ..., hn  h1,  h2,  ...,  hn
       stand  for  horizontal distances where positive means right, negative left.  The arguments called v1,
       v2, ..., vn v1, v2, ..., vn stand for vertical distances where positive means down, negative up.  All
       these distances are offsets relative to the current location.

       Unless  indicated  otherwise, each graphics command directly corresponds to a similar groff \D escape
       sequence; see groff(7).

       Unknown D commands are assumed to be device-specific.  Its arguments are parsed as strings; the whole
       information is then sent to the postprocessor.

       In the following command reference, the syntax element <line_break> means a syntactical line break as
       defined in section Separation.

       D~ h1 v1 h2 v2 ... hn vn<line_break>
              Draw B-spline from current position to offset (h1, v1), then to offset (h2, v2) if given, etc.
              up  to  (hn, vn). This command takes a variable number of argument pairs; the current position
              is moved to the terminal point of the drawn curve.

       Da h1 v1 h2 v2<line_break>
              Draw arc from current position to (h1, v1)+(h2, v2) with center at  (h1, v1);  then  move  the
              current position to the final point of the arc.

       DC d<line_break>
       DC d dummy_arg<line_break>
              Draw  a  solid  circle using the current fill color with diameter d (integer in basic units u)
              with leftmost point at the current position; then move the current position to  the  rightmost
              point  of the circle.  An optional second integer argument is ignored (this allows to the for-matter formatter
              matter to generate an even number of arguments).  This command is a groff extension.

       Dc d<line_break>
              Draw circle line with diameter d (integer in basic units u) with leftmost point at the current
              position; then move the current position to the rightmost point of the circle.

       DE h v<line_break>
              Draw  a solid ellipse in the current fill color with a horizontal diameter of h and a vertical
              diameter of v (both integers in basic units u) with the leftmost point at  the  current  posi-tion; position;
              tion; then move to the rightmost point of the ellipse.  This command is a groff extension.

       De h v<line_break>
              Draw  an  outlined  ellipse with a horizontal diameter of h and a vertical diameter of v (both
              integers in basic units u) with the leftmost point at  current  position;  then  move  to  the
              rightmost point of the ellipse.

       DF color_scheme [component ...]<line_break>
              Set fill color for solid drawing objects using different color schemes; the analoguous command
              for setting the color of text, line graphics, and the outline of graphic objects  is  m.   The
              color  components are specified as integer arguments between 0 and 65536.  The number of color
              components and their meaning vary for the different color schemes.  These commands are  gener-ated generated
              ated  by  the  groff  escape sequences \D'F ...'  and \M (with no other corresponding graphics
              commands).  No position changing.  This command is a groff extension.

              DFc cyan magenta yellow<line_break>
                     Set fill color for solid drawing objects using the CMY color scheme, having the 3 color
                     components cyan, magenta, and yellow.

              DFd <line_break>
                     Set fill color for solid drawing objects to the default fill color value (black in most
                     cases).  No component arguments.

              DFg gray<line_break>
                     Set fill color for solid drawing objects to the shade of gray given by the argument, an
                     integer between 0 (black) and 65536 (white).

              DFk cyan magenta yellow black<line_break>
                     Set  fill  color  for  solid  drawing  objects  using the CMYK color scheme, having the
                     4 color components cyan, magenta, yellow, and black.

              DFr red green blue<line_break>
                     Set fill color for solid drawing objects using the RGB color scheme, having the 3 color
                     components red, green, and blue.

       Df n<line_break>
              The argument n must be an integer in the range -32767 to 32767.

              0 <= n <= 1000
                     Set the color for filling solid drawing objects to a shade of gray, where 0 corresponds
                     to solid white, 1000 (the default) to solid black, and values in between to  intermedi-
                     ate shades of gray; this is obsoleted by command DFg.

              n < 0 or n > 1000
                     Set  the  filling  color to the color that is currently being used for the text and the
                     outline, see command m.  For example, the command sequence
                            mg 0 0 65536
                            Df -1
                     sets all colors to blue.

              No position changing.  This command is a groff extension.

       Dl h v<line_break>
              Draw line from current position to offset (h, v) (integers in basic units u); then set current
              position to the end of the drawn line.

       Dp h1 v1 h2 v2 ... hn vn<line_break>
              Draw  a  polygon line from current position to offset (h1, v1), from there to offset (h2, v2),
              etc. up to offset (hn, vn), and from there back to the starting position.  For historical rea-sons, reasons,
              sons,  the position is changed by adding the sum of all arguments with odd index to the actual
              horizontal position and the even ones to the vertical position.  Although  this  doesn't  make
              sense it is kept for compatibility.  This command is a groff extension.

       DP h1 v1 h2 v2 ... hn vn<line_break>
              The  same  macro  as  the  corresponding Dp command with the same arguments, but draws a solid
              polygon in the current fill color rather than an outlined polygon.  The position is changed in
              the same way as with Dp.  This command is a groff extension.

       Dt n<line_break>
              Set  the  current  line thickness to n (an integer in basic units u) if n>0; if n=0 select the
              smallest available line thickness; if n<0 set the line thickness  proportional  to  the  point
              size (this is the default before the first Dt command was specified).  For historical reasons,
              the horizontal position is changed by adding the argument to the actual  horizontal  position,
              while  the  vertical position is not changed.  Although this doesn't make sense it is kept for
              compatibility.  This command is a groff extension.

   Device Control Commands
       Each device control command starts with the letter x followed by a space character (optional or arbi-
       trary space/tab in groff) and a subcommand letter or word; each argument (if any) must be preceded by
       a syntactical space.  All x commands are terminated by a syntactical line break;  no  device  control
       command can be followed by another command on the same line (except a comment).

       The  subcommand  is  basically  a  single letter, but to increase readability, it can be written as a
       word, i.e., an arbitrary sequence of characters terminated by the next tab, space, or newline charac-ter. character.
       ter.   All  characters  of  the subcommand word but the first are simply ignored.  For example, troff
       outputs the initialization command x i as x init and the resolution command x r as x res.  But  writ-ings writings
       ings like x i_like_groff and x roff_is_groff resp. are accepted as well to mean the same commands.

       In  the  following, the syntax element <line_break> means a syntactical line break as defined in sec-tion section
       tion Separation.

       xF name<line_break>
              (Filename control command)
              Use name as the intended name for the current file in  error  reports.   This  is  useful  for
              remembering  the  original  file name when groff uses an internal piping mechanism.  The input
              file is not changed by this command.  This command is a groff extension.

       xf n s<line_break>
              (font control command)
              Mount font position n  (a  non-negative  integer)  with  font  named  s  (a  text  word),  cf.
              groff_font(5).

       xH n<line_break>
              (Height control command)
              Set  character  height to n (a positive integer in scaled points z).  Classical troff used the
              unit points (p) instead; see section COMPATIBILITY.

       xi<line_break>
              (init control command)
              Initialize device.  This is the third command of the prologue.

       xp<line_break>
              (pause control command)
              Parsed but ignored.  The classical documentation reads pause device, can be restarted.

       xr n h v<line_break>
              (resolution control command)
              Resolution is n, while h is the minimal horizontal motion, and v the minimal  vertical  motion
              possible  with  this  device;  all  arguments are positive integers in basic units u per inch.
              This is the second command of the prologue.

       xS n<line_break>
              (Slant control command)
              Set slant to n degrees (an integer in basic units u).

       xs<line_break>
              (stop control command)
              Terminates the processing of the current file; issued as the last command of any  intermediate
              troff output.

       xt<line_break>
              (trailer control command)
              Generate trailer information, if any.  In groff, this is actually just ignored.

       xT xxx<line_break>
              (Typesetter control command)
              Set  name of device to word xxx, a sequence of characters ended by the next whitespace charac-ter. character.
              ter.  The possible device names coincide with those from the groff -T  option.   This  is  the
              first command of the prologue.

       xu n<line_break>
              (underline control command)
              Configure  underlining  of  spaces.   If  n is 1, start underlining of spaces; if n is 0, stop
              underlining of spaces.  This is needed for the cu request in nroff mode and is ignored  other-wise. otherwise.
              wise.  This command is a groff extension.

       xX anything<line_break>
              (X-escape control command)
              Send  string  anything uninterpreted to the device.  If the line following this command starts
              with a + character this line is interpreted as a continuation line  in  the  following  sense.
              The  + is ignored, but a newline character is sent instead to the device, the rest of the line
              is sent uninterpreted.  The same applies to all following lines until the first character of a
              line  is  not  a + character.  This command is generated by the groff escape sequence \X.  The
              line-continuing feature is a groff extension.

   Obsolete Command
       In classical troff output, the writing of a single character was mostly done by a very  strange  com-mand command
       mand that combined a horizontal move and the printing of a character.  It didn't have a command code,
       but is represented by a 3-character argument consisting of exactly 2 digits and a character.

       ddc    Move right dd (exactly two decimal digits) basic units u, then print character c.

              In groff, arbitrary syntactical space around and within this command is allowed to  be  added.
              Only when a preceding command on the same line ends with an argument of variable length a sep-arating separating
              arating space is obligatory.  In classical troff, large clusters of these and  other  commands
              were used, mostly without spaces; this made such output almost unreadable.

       For modern high-resolution devices, this command does not make sense because the width of the charac-ters characters
       ters can become much larger than two decimal digits.  In groff, this is only  used  for  the  devices
       X75, X75-12, X100, and X100-12.  For other devices, the commands t and u provide a better functional-ity. functionality.
       ity.

POSTPROCESSING
       The roff postprocessors are programs that have the task to translate  the  intermediate  output  into
       actions  that  are  sent to a device.  A device can be some piece of hardware such as a printer, or a
       software file format suitable for graphical or text processing.  The groff system  provides  powerful
       means that make the programming of such postprocessors an easy task.

       There is a library function that parses the intermediate output and sends the information obtained to
       the device via methods of a class with a common interface for each device.  So a groff  postprocessor
       must only redefine the methods of this class.  For details, see the reference in section FILES.

EXAMPLES
       This  section  presents  the  intermediate  output  generated from the same input for three different
       devices.  The input is the sentence hell world fed into groff on the command line.

        High-resolution device ps

         shell> echo hell world | groff -Z -T ps

         x T ps
         x res 72000 1 1
         x init
         p1
         x font 5 TR
         f5
         s10000
         V12000
         H72000
         thell
         wh2500
         tw
         H96620
         torld
         n12000 0
         x trailer
         V792000
         x stop

       This output can be fed into the postprocessor grops(1) to get  its  representation  as  a  PostScript
       file.

        Low-resolution device latin1

         This is similar to the high-resolution device except that the positioning is done at a minor scale.
         Some comments (lines starting with #) were added for clarification; they were not generated by  the
         formatter.

         shell> echo hell world | groff -Z -T latin1

         # prologue
         x T latin1
         x res 240 24 40
         x init
         # begin a new page
         p1
         # font setup
         x font 1 R
         f1
         s10
         # initial positioning on the page
         V40
         H0
         # write text `hell'
         thell
         # inform about a space, and do it by a horizontal jump
         wh24
         # write text `world'
         tworld
         # announce line break, but do nothing because ...
         n40 0
         # ... the end of the document has been reached
         x trailer
         V2640
         x stop

       This output can be fed into the postprocessor grotty(1) to get a formatted text document.

        Classical style output

         As a computer monitor has a very low resolution compared to modern printers the intermediate output
         for the X devices can use the jump-and-write command with its 2-digit displacements.

         shell> echo hell world | groff -Z -T X100

         x T X100
         x res 100 1 1
         x init
         p1
         x font 5 TR
         f5
         s10
         V16
         H100
         # write text with old-style jump-and-write command
         ch07e07l03lw06w11o07r05l03dh7
         n16 0
         x trailer
         V1100
         x stop

       This output can be fed into the postprocessor xditview(1x) or gxditview(1) for displaying in X.

       Due to the obsolete jump-and-write command, the text clusters in  the  classical  output  are  almost
       unreadable.

COMPATIBILITY
       The  intermediate  output  language  of  the classical troff was first documented in [CSTR #97].  The
       groff intermediate output format is compatible with this specification except for the following  fea-tures. features.
       tures.

        The classical quasi device independence is not yet implemented.

        The  old  hardware was very different from what we use today.  So the groff devices are also funda-mentally fundamentally
         mentally different from the ones in classical troff.  For example, the classical PostScript  device
         was  called  post and had a resolution of 720 units per inch, while groff's ps device has a resolu-tion resolution
         tion of 72000 units per inch.  Maybe, by implementing some rescaling mechanism similar to the clas-sical classical
         sical quasi device independence, these could be integrated into modern groff.

        The  B-spline  command  D~  is correctly handled by the intermediate output parser, but the drawing
         routines aren't implemented in some of the postprocessor programs.

        The argument of the commands s and x H has the implicit unit scaled point z in groff, while classi-cal classical
         cal troff had point (p).  This isn't an incompatibility, but a compatible extension, for both units
         coincide for all devices without a sizescale parameter, including all classical and the groff  text
         devices.   The  few  groff devices with a sizescale parameter either did not exist, had a different
         name, or seem to have had a different resolution.  So conflicts with  classical  devices  are  very
         unlikely.

        The  position changing after the commands Dp, DP, and Dt is illogical, but as old versions of groff
         used this feature it is kept for compatibility reasons.

       The differences between groff and classical troff are documented in groff_diff(7).

FILES
       /usr/share/groff/1.19.2/font/devname/DESC
              Device description file for device name.

       <groff_source_dir>/src/libs/libdriver/input.cpp
              Defines the parser and postprocessor for the intermediate output.  It is located  relative  to
              the  top  directory of the groff source tree, e.g.  @GROFFSRCDIR@.  This parser is the defini-tive definitive
              tive specification of the groff intermediate output format.

SEE ALSO
       A reference like groff(7) refers to a manual page; here groff in section 7 of the man-page documenta-tion documentation
       tion  system.   To  read  the example, look up section 7 in your desktop help system or call from the
       shell prompt

              shell> man 7 groff

       For more details, see man(1).

       groff(1)
              option -Z and further readings on groff.

       groff(7)
              for details of the groff language such as numerical units and escape sequences.

       groff_font(5)
              for details on the device scaling parameters of the DESC file.

       troff(1)
              generates the device-independent intermediate output.

       roff(7)
              for historical aspects and the general structure of roff systems.

       groff_diff(7)
              The differences between the intermediate output in groff and classical troff.

       gxditview(1)
              Viewer for the intermediate output.

       grodvi(1), grohtml(1), grolbp(1), grolj4(1), grops(1), grotty(1)
              the groff postprocessor programs.

       For a treatment of all aspects of the groff system within a single document, see the groff info file.
       It can be read within the integrated help systems, within emacs(1) or from the shell prompt by
              shell> info groff

       The  classical  troff output language is described in two AT&T Bell Labs CSTR documents available on-line online
       line at Bell Labs CSTR site <http://cm.bell-labs.com/cm/cs/cstr.html>.

       [CSTR #97]
              A Typesetter-independent TROFF by Brian Kernighan is the original and most concise  documenta-tion documentation
              tion on the output language; see CSTR #97 <http://cm.bell-labs.com/cm/cs/cstr/97.ps.gz>.

       [CSTR #54]
              The  1992  revision of the Nroff/Troff User's Manual by J. F. Osanna and Brian Kernighan isn't
              as concise as [CSTR #97] regarding the output language; see CSTR #54 <http://cm.bell-labs.com/
              cm/cs/cstr/54.ps.gz>.

AUTHORS
       Copyright (C) 1989, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.

       This  document is distributed under the terms of the FDL (GNU Free Documentation License) version 1.1
       or later.  You should have received a copy of the FDL with this package; it is also available on-line
       at the GNU copyleft site <http://www.gnu.org/copyleft/fdl.html>.

       This  document  is  part of groff, the GNU roff distribution.  It is based on a former version - pub-lished published
       lished under the GPL - that described only parts of the groff extensions of the output language.   It
       has been rewritten 2002 by Bernd Warken and is maintained by

       Werner Lemberg <wl@gnu.org>.



Groff Version 1.19.2                             3 July 2005                                    GROFF_OUT(5)

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