term(5) File formats term(5) #
term(5) File formats term(5)
NNAAMMEE #
term - format of compiled term file.
SSYYNNOOPPSSIISS #
tteerrmm
DDEESSCCRRIIPPTTIIOONN #
SSTTOORRAAGGEE LLOOCCAATTIIOONN #
Compiled terminfo descriptions are placed under the directory
//uussrr//sshhaarree//tteerrmmiinnffoo. Two configurations are supported (when building the
nnccuurrsseess libraries):
ddiirreeccttoorryy ttrreeee
A two-level scheme is used to avoid a linear search of a huge UNIX
system directory: //uussrr//sshhaarree//tteerrmmiinnffoo//cc//nnaammee where _n_a_m_e is the name
of the terminal, and _c is the first character of _n_a_m_e. Thus, _a_c_t_4
can be found in the file //uussrr//sshhaarree//tteerrmmiinnffoo//aa//aacctt44. Synonyms for
the same terminal are implemented by multiple links to the same
compiled file.
hhaasshheedd ddaattaabbaassee
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, nnccuurrsseess 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.
nnccuurrsseess 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.
LLEEGGAACCYY SSTTOORRAAGGEE FFOORRMMAATT #
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 ttiicc program, and read by the
routine sseettuupptteerrmm(3). The file is divided into six parts:
a) _h_e_a_d_e_r,
b) _t_e_r_m_i_n_a_l _n_a_m_e_s,
c) _b_o_o_l_e_a_n _f_l_a_g_s,
d) _n_u_m_b_e_r_s,
e) _s_t_r_i_n_g_s, and
f) _s_t_r_i_n_g _t_a_b_l_e.
The _h_e_a_d_e_r section begins the file. This section contains six short
integers in the format described below. These integers are
(1) the _m_a_g_i_c _n_u_m_b_e_r (octal 0432);
(2) the size, in bytes, of the _t_e_r_m_i_n_a_l _n_a_m_e_s section;
(3) the number of bytes in the _b_o_o_l_e_a_n _f_l_a_g_s section;
(4) the number of short integers in the _n_u_m_b_e_r_s section;
(5) the number of offsets (short integers) in the _s_t_r_i_n_g_s section;
(6) the size, in bytes, of the _s_t_r_i_n_g _t_a_b_l_e.
The capabilities in the _b_o_o_l_e_a_n _f_l_a_g_s, _n_u_m_b_e_r_s, and _s_t_r_i_n_g_s 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 contains 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
_n_u_m_b_e_r_s or _s_t_r_i_n_g_s 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 corresponding 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 _t_e_r_m_i_n_a_l _n_a_m_e_s section comes after the _h_e_a_d_e_r. It contains the first
line of the terminfo description, listing the various names for the
terminal, separated by the “|” character. The _t_e_r_m_i_n_a_l _n_a_m_e_s section is
terminated with an ASCII NUL character.
The _b_o_o_l_e_a_n _f_l_a_g_s 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 _b_o_o_l_e_a_n _f_l_a_g_s section and the _n_u_m_b_e_r section, a null byte
will be inserted, if necessary, to ensure that the _n_u_m_b_e_r 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 addressing a
word on an odd byte boundary. All short integers are aligned on a short
word boundary.
The _n_u_m_b_e_r_s section is similar to the _b_o_o_l_e_a_n _f_l_a_g_s section. Each
capability takes up two bytes, and is stored as a little-endian short
integer.
The _s_t_r_i_n_g_s section is also similar. Each capability is stored as a
short integer. The capability value is an index into the _s_t_r_i_n_g _t_a_b_l_e.
The _s_t_r_i_n_g _t_a_b_l_e is the last section. It contains all of the values of
string capabilities referenced in the _s_t_r_i_n_g_s section. Each string is
null-terminated. Special characters in ^X or \c notation are stored in
their interpreted form, not the printing representation. Padding
information $<nn> and parameter information %x are stored intact in
uninterpreted form.
EEXXTTEENNDDEEDD SSTTOORRAAGGEE FFOORRMMAATT #
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 nnccuurrsseess 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. nnccuurrsseess 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 _n_a_m_e_s as well as extended capability _v_a_l_u_e_s.
Using the counts and sizes, nnccuurrsseess allocates arrays and reads data for
the extended capabilities 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 tteerrmm__vvaarriiaabblleess(3) which associate the long capability names
with members of a TTEERRMMTTYYPPEE structure.
EEXXTTEENNDDEEDD NNUUMMBBEERR FFOORRMMAATT #
On occasion, 16-bit signed integers are not large enough. With nnccuurrsseess
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 _n_u_m_b_e_r array from signed 16-bit integers to
signed 32-bit integers.
To maintain compatibility, the library presents the same data structures
to direct users of the TTEERRMMTTYYPPEE structure as in previous formats.
However, that cannot provide callers with the extended numbers. The
library uses a similar but hidden data structure TTEERRMMTTYYPPEE22 to provide
data for the terminfo functions.
PPOORRTTAABBIILLIITTYY #
sseettuupptteerrmm Note that it is possible for sseettuupptteerrmm to expect a different set of capabilities than are actually present in the file. Either the database may have been updated since sseettuupptteerrmm 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 sseettuupptteerrmm 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.
BBiinnaarryy ffoorrmmaatt 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
extension capabilities to the string table that (in the binary format)
collide with System V and XSI Curses extensions. See tteerrmmiinnffoo(5) for
detailed discussion of terminfo source compatibility 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.
MMaaggiicc ccooddeess 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 ffiillee(1) 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 ssccrr__dduummpp(5)). This implementation uses 01036 as a continuation of that sequence, but with a different high-order byte to avoid confusion.
TThhee TTEERRMMTTYYPPEE ssttrruuccttuurree Direct access to the TTEERRMMTTYYPPEE structure is provided for legacy applications. Portable applications should use the ttiiggeettffllaagg and related functions described in tteerrmmiinnffoo(3) for reading terminal capabilities.
MMiixxeedd--ccaassee tteerrmmiinnaall nnaammeess A small number of terminal descriptions use uppercase characters in their names. If the underlying filesystem ignores the difference between uppercase and lowercase, nnccuurrsseess represents the “first character” of the terminal name used as the intermediate level of a directory tree in (two- character) hexadecimal form.
EEXXAAMMPPLLEE #
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 ........ .
LLIIMMIITTSS #
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
_s_t_r_i_n_g_s _t_a_b_l_e use two-byte integers. The legacy format could have
supported 32768-byte entries, but was limited a virtual memory page's
4096 bytes.
FFIILLEESS #
/usr/share/terminfo/*/* compiled terminal capability database
SSEEEE AALLSSOO #
ccuurrsseess(3), tteerrmmiinnffoo(5).
AAUUTTHHOORRSS #
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 _p_c_u_r_s_e_s.
ncurses 6.4 2023-07-01 term(5)