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term(5)
NAME SYNOPSIS DESCRIPTION PORTABILITY EXAMPLE LIMITS FILES SEE ALSO AUTHORS
term(5)                                  File Formats Manual                                 term(5)



NAME
       term - format of compiled term file.

SYNOPSIS
       term

DESCRIPTION
   STORAGE LOCATION
       Compiled  terminfo descriptions are placed under the directory /etc/terminfo.  Two configura‐
       tions are supported (when building the ncurses libraries):

       directory tree
            A two-level scheme is used to avoid a linear search of a  huge  UNIX  system  directory:
            /etc/terminfo/c/name  where name is the name of the terminal, and c is the first charac‐
            ter of name.  Thus, act4 can be found in the file  /etc/terminfo/a/act4.   Synonyms  for
            the same terminal are implemented by multiple links to the same compiled file.

       hashed database
            Using  Berkeley database, two types of records are stored: the terminfo data in the same
            format as stored in a directory tree with the terminfo's primary  name  as  a  key,  and
            records containing only aliases pointing to the primary name.

            If  built to write hashed databases, ncurses can still read terminfo databases organized
            as a directory tree, but cannot write entries into the directory tree.  It can write (or
            rewrite) entries in the hashed database.

            ncurses  distinguishes the two cases in the TERMINFO and TERMINFO_DIRS environment vari‐
            able by assuming a directory tree for entries that correspond to an existing  directory,
            and hashed database otherwise.

   LEGACY STORAGE FORMAT
       The  format  has  been  chosen so that it will be the same on all hardware.  An 8 or more bit
       byte is assumed, but no assumptions about byte ordering or sign extension are made.

       The compiled file is created with the tic program, and read  by  the  routine  setupterm(3X).
       The file is divided into six parts:

            a) header,

            b) terminal names,

            c) boolean flags,

            d) numbers,

            e) strings, and

            f) string table.

       The  header  section begins the file.  This section contains six short integers in the format
       described below.  These integers are

            (1) the magic number (octal 0432);

            (2) the size, in bytes, of the terminal names section;

            (3) the number of bytes in the boolean flags section;

            (4) the number of short integers in the numbers section;

            (5) the number of offsets (short integers) in the strings section;

            (6) the size, in bytes, of the string table.

       The capabilities in the boolean flags, numbers, and strings sections are in the same order as
       the file <term.h>.

       Short integers are signed, in the range -32768 to 32767.  They are stored as two 8-bit bytes.
       The first byte contains the least significant 8 bits of the value, and the second  byte  con‐
       tains  the most significant 8 bits.  (Thus, the value represented is 256*second+first.)  This
       format corresponds to the hardware of the VAX and PDP-11 (that is,  little-endian  machines).
       Machines  where  this does not correspond to the hardware must read the integers as two bytes
       and compute the little-endian value.

       Numbers in a terminal description, whether they are entries in the numbers or strings  table,
       are  positive  integers.   Boolean  flags are treated as positive one-byte integers.  In each
       case, those positive integers represent a terminal capability.   The  terminal  compiler  tic
       uses negative integers to handle the cases where a capability is not available:

       •   If a capability is absent from this terminal, tic stores a -1 in the corresponding table.

           The integer value -1 is represented by two bytes 0377, 0377.
           Absent boolean values are represented by the byte 0 (false).

       •   If  a capability has been canceled from this terminal, tic stores a -2 in the correspond‐
           ing table.

           The integer value -2 is represented by two bytes 0377, 0376.
           The boolean value -2 is represented by the byte 0376.

       •   Other negative values are illegal.

       The terminal names section comes after the header.  It contains the first line  of  the  ter‐
       minfo  description,  listing the various names for the terminal, separated by the “|” charac‐
       ter.  The terminal names section is terminated with an ASCII NUL character.

       The boolean flags section has one byte for each flag.  Boolean capabilities are either 1 or 0
       (true or false) according to whether the terminal supports the given capability or not.

       Between  the  boolean  flags section and the number section, a null byte will be inserted, if
       necessary, to ensure that the number section begins on an even byte This is a  relic  of  the
       PDP-11's  word-addressed architecture, originally designed to avoid traps induced by address‐
       ing a word on an odd byte boundary.  All short integers are aligned on a short word boundary.

       The numbers section is similar to the boolean flags section.  Each capability  takes  up  two
       bytes, and is stored as a little-endian short integer.

       The  strings section is also similar.  Each capability is stored as a short integer.  The ca‐
       pability value is an index into the string table.

       The string table is the last section.  It contains all of the values of  string  capabilities
       referenced in the strings section.  Each string is null-terminated.  Special characters in ^X
       or \c notation are stored in their interpreted form, not the printing  representation.   Pad‐
       ding information $<nn> and parameter information %x are stored intact in uninterpreted form.

   EXTENDED STORAGE FORMAT
       The  previous  section  describes  the  conventional terminfo binary format.  With some minor
       variations of the offsets (see PORTABILITY), the same binary format is  used  in  all  modern
       UNIX systems.  Each system uses a predefined set of boolean, number or string capabilities.

       The  ncurses  libraries  and  applications  support extended terminfo binary format, allowing
       users to define capabilities which are loaded at runtime.  This extension is made possible by
       using  the  fact that the other implementations stop reading the terminfo data when they have
       reached the end of the size given in the header.  ncurses checks the size, and if it  exceeds
       that due to the predefined data, continues to parse according to its own scheme.

       First, it reads the extended header (5 short integers):

            (1)  count of extended boolean capabilities

            (2)  count of extended numeric capabilities

            (3)  count of extended string capabilities

            (4)  count of the items in extended string table

            (5)  size of the extended string table in bytes

       The  count-  and  size-values  for  the extended string table include the extended capability
       names as well as extended capability values.

       Using the counts and sizes, ncurses allocates arrays and reads data for the extended capabil‐
       ities in the same order as the header information.

       The  extended  string  table contains values for string capabilities.  After the end of these
       values, it contains the names for each of the extended capabilities in order, e.g., booleans,
       then numbers and finally strings.

       Applications  which  manipulate terminal data can use the definitions described in term_vari‐‐
       ables(3X) which associate the long capability names with members of a TERMTYPE structure.

   EXTENDED NUMBER FORMAT
       On occasion, 16-bit signed integers are not large enough.  With ncurses 6.1, a new format was
       introduced by making a few changes to the legacy format:

       •   a different magic number (octal 01036)

       •   changing the type for the number array from signed 16-bit integers to signed 32-bit inte‐
           gers.

       To maintain compatibility, the library presents the same data structures to direct  users  of
       the TERMTYPE structure as in previous formats.  However, that cannot provide callers with the
       extended numbers.  The library uses a similar but hidden data structure TERMTYPE2 to  provide
       data for the terminfo functions.

PORTABILITY
   setupterm
       Note that it is possible for setupterm to expect a different set of capabilities than are ac‐
       tually present in the file.  Either the database may have been updated  since  setupterm  was
       recompiled (resulting in extra unrecognized entries in the file) or the program may have been
       recompiled more recently than the database was updated (resulting in missing  entries).   The
       routine setupterm must be prepared for both possibilities - this is why the numbers and sizes
       are included.  Also, new capabilities must always be added at the end of the lists  of  bool‐
       ean, number, and string capabilities.

   Binary format
       X/Open Curses does not specify a format for the terminfo database.  UNIX System V curses used
       a directory-tree of binary files, one per terminal description.

       Despite the consistent use of little-endian for numbers  and  the  otherwise  self-describing
       format,  it is not wise to count on portability of binary terminfo entries between commercial
       UNIX versions.  The problem is that there are at least  three  versions  of  terminfo  (under
       HP-UX,  AIX,  and OSF/1) which diverged from System V terminfo after SVr1, and have added ex‐
       tension capabilities to the string table that (in the binary format) collide  with  System  V
       and  XSI  Curses extensions.  See terminfo(5) for detailed discussion of terminfo source com‐
       patibility issues.

       This implementation is by default compatible with the binary terminfo format used by  Solaris
       curses,  except  in  a few less-used details where it was found that the latter did not match
       X/Open Curses.  The format used by the other Unix versions can be matched by building ncurses
       with different configuration options.

   Magic codes
       The  magic number in a binary terminfo file is the first 16-bits (two bytes).  Besides making
       it more reliable for the library to check that a file is terminfo,  utilities  such  as  file
       also  use that to tell what the file-format is.  System V defined more than one magic number,
       with 0433, 0435 as screen-dumps (see scr_dump(5)).  This implementation uses 01036 as a  con‐
       tinuation of that sequence, but with a different high-order byte to avoid confusion.

   The TERMTYPE structure
       Direct access to the TERMTYPE structure is provided for legacy applications.  Portable appli‐
       cations should use the tigetflag and related functions  described  in  curs_terminfo(3X)  for
       reading terminal capabilities.

   Mixed-case terminal names
       A  small number of terminal descriptions use uppercase characters in their names.  If the un‐
       derlying filesystem ignores the difference between uppercase and  lowercase,  ncurses  repre‐
       sents  the  “first character” of the terminal name used as the intermediate level of a direc‐
       tory tree in (two-character) hexadecimal form.

EXAMPLE
       As an example, here is a description for the Lear-Siegler  ADM-3,  a  popular  though  rather
       stupid early terminal:

           adm3a|lsi adm3a,
                   am,
                   cols#80, lines#24,
                   bel=^G, clear= 32$<1>, cr=^M, cub1=^H, cud1=^J,
                   cuf1=^L, cup=\E=%p1%{32}%+%c%p2%{32}%+%c, cuu1=^K,
                   home=^^, ind=^J,


       and a hexadecimal dump of the compiled terminal description:

           0000  1a 01 10 00 02 00 03 00  82 00 31 00 61 64 6d 33  ........ ..1.adm3
           0010  61 7c 6c 73 69 20 61 64  6d 33 61 00 00 01 50 00  a|lsi ad m3a...P.
           0020  ff ff 18 00 ff ff 00 00  02 00 ff ff ff ff 04 00  ........ ........
           0030  ff ff ff ff ff ff ff ff  0a 00 25 00 27 00 ff ff  ........ ..%.'...
           0040  29 00 ff ff ff ff 2b 00  ff ff 2d 00 ff ff ff ff  ).....+. ..-.....
           0050  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           0060  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           0070  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           0080  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           0090  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           00a0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           00b0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           00c0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           00d0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           00e0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           00f0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           0100  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           0110  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ........ ........
           0120  ff ff ff ff ff ff 2f 00  07 00 0d 00 1a 24 3c 31  ....../. .....$<1
           0130  3e 00 1b 3d 25 70 31 25  7b 33 32 7d 25 2b 25 63  >..=%p1% {32}%+%c
           0140  25 70 32 25 7b 33 32 7d  25 2b 25 63 00 0a 00 1e  %p2%{32} %+%c....
           0150  00 08 00 0c 00 0b 00 0a  00                       ........ .


LIMITS
       Some limitations:

       •   total compiled entries cannot exceed 4096 bytes in the legacy format.

       •   total compiled entries cannot exceed 32768 bytes in the extended format.

       •   the name field cannot exceed 128 bytes.

       Compiled  entries  are limited to 32768 bytes because offsets into the strings table use two-
       byte integers.  The legacy format could have supported 32768-byte entries, but was limited  a
       virtual memory page's 4096 bytes.

FILES
       /etc/terminfo/*/*   compiled terminal capability database

SEE ALSO
       ncurses(3NCURSES), terminfo(5).

AUTHORS
       Thomas E. Dickey
       extended terminfo format for ncurses 5.0
       hashed database support for ncurses 5.6
       extended number support for ncurses 6.1

       Eric S. Raymond
       documented legacy terminfo format, e.g., from pcurses.



                                                                                             term(5)

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