term - format of compiled term file.
term
NOTE: OpenBSD uses a Berkeley DB-style terminfo database
instead of the SVR4 method of one description per file
described below.
Compiled terminfo descriptions are placed under the directory
/usr/share/terminfo. In order to avoid a linear
search of a huge UNIX system directory, a two-level scheme
is used: /c/name where name is the name of the terminal,
and c is the first character of name. Thus, act4 can be
found in the file /usr/share/terminfo/a/act4. Synonyms
for the same terminal are implemented by multiple links to
the same compiled file.
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 format 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 significant 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 if the flag is present or absent. The
capabilities are in the same order as the file <term.h>.
Between the boolean 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 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 littleendian
short integer. If the value represented is -1, the
capability 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 stored
in their interpreted form, not the printing representation.
Padding information $<nn> and parameter information
%x are stored intact in uninterpreted form.
The final section is the string table. It contains all
the values of string capabilities referenced in the string
section. Each string is null terminated.
Note that it is possible for setupterm to expect a different
set of capabilities than are actually present in the
file. Either the database may have been updated since
setupterm was recompiled (resulting in extra unrecognized
entries in the file) or the program may have been recompiled
more recently than the database was updated (resulting
in missing entries). The routine setupterm must be
prepared for both possibilities - this is why the numbers
and sizes are included. Also, new capabilities must
always be added at the end of the lists of boolean, number,
and string capabilities.
Despite the consistent use of little-endian for numbers
and the otherwise self-describing format, it is not wise
to count on portability of binary terminfo entries between
commercial UNIX versions. The problem is that there are
at least three versions of terminfo (under HP-UX, AIX, and
OSF/1) which diverged from System V terminfo after SVr1,
and have added extension capabilities to the string table
that (in the binary format) collide with System V and XSI
Curses extensions. See terminfo(5) for detailed discussion
of terminfo source compatibility issues.
As an example, here is a hex dump of the description for
the Lear-Siegler ADM-3, a popular though rather stupid
early terminal:
adm3a|lsi adm3a,
am,
cols#80, lines#24,
bel=^G, clear= 32$<1>, cr=^M, cub1=^H, cud1=^J,
cuf1=^L, cup==%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
........ .
Some limitations: total compiled entries cannot exceed
4096 bytes. The name field cannot exceed 128 bytes.
/usr/share/terminfo/*/* compiled terminal capability data
base
curses(3), terminfo(5).
[ Back ] |
