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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 configu‐
       rations 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 char‐
            acter 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 orga‐
            nized 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
            variable by assuming a directory tree for entries  that  correspond  to  an  existing
            directory, and hashed database otherwise.

   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.  The
       file  is  divided  into  six  parts:  the  header, terminal names, boolean flags, numbers,
       strings, and string table.

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

            (1) the magic number (octal 0432);

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

            (3) the number of bytes in the boolean 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.

       Short  integers are stored in two 8-bit bytes.  The first byte contains the least signifi‐
       cant 8 bits of the value, and the second  byte  contains  the  most  significant  8  bits.
       (Thus, the value represented is 256*second+first.)  The value -1 is represented by the two
       bytes 0377, 0377; other negative values are illegal. This value generally means  that  the
       corresponding capability is missing from this terminal.  Note that 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.

       The terminal names section comes next.   It  contains  the  first  line  of  the  terminfo
       description,  listing  the various names for the terminal, separated by the `|' character.
       The section is terminated with an ASCII NUL character.

       The boolean flags have one byte for each flag.  This byte is either 0 or 1 as the flag  is
       present or absent.  The capabilities are in the same order as the file .

       Between  the boolean section and the number section, a null byte will be inserted, if nec‐
       essary, 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 in to avoid IOT traps induced by
       addressing a word on an odd byte boundary).  All short integers are  aligned  on  a  short
       word boundary.

       The  numbers section is similar to the flags section.  Each capability takes up two bytes,
       and is stored as a little-endian short integer.  If the value represented is -1, the capa‐
       bility is taken to be missing.

       The strings section is also similar.  Each capability is stored as a short integer, in the
       format above.  A value of -1 means the capability is missing.   Otherwise,  the  value  is
       taken as an offset from the beginning of the string table.  Special characters in ^X or \c
       notation are stored in their interpreted form, not the printing  representation.   Padding
       information $ and parameter information %x are stored intact in uninterpreted form.

       The  final section is the string table.  It contains all the values of string capabilities
       referenced in the string section.  Each string is null terminated.

   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  capabili‐
       ties.

       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)  size of the extended string table in bytes.

            (5)  last offset of the extended string table in bytes.

       Using the counts and sizes, ncurses allocates arrays and reads data for the extended capa‐
       bilities 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., bool‐
       eans, then numbers and finally strings.

PORTABILITY
       Note that it is possible for setupterm to expect a different set of capabilities than  are
       actually  present  in the file.  Either the database may have been updated since setupterm
       has been 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 boolean, number, and string capabilities.

       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 commer‐
       cial 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 extension 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 compatibility issues.

EXAMPLE
       As an example, here is a hex dump of the 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,

       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.  The name field cannot
       exceed 128 bytes.

FILES
       /etc/terminfo/*/*   compiled terminal capability data base

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

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

       Eric S. Raymond

                                                                                          term(5)

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