TERM(5)

NAME
term - format of compiled term file.

SYNOPSIS
term

DESCRIPTION

Compiled terminfo descriptions are placed under the directory /usr/lib/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/lib/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. Both of these pieces of software are part of ncurses(3). 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 0377, 0377, other negative value are illegal. The -1 generally means that a capability is missing from this terminal. Note that this format corresponds to the hardware of the VAX and PDP-11. Machines where this does not correspond to the hardware read the integers as two bytes and compute the result.

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 <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. 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 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 \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.

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 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.

As an example, an octal dump of the description for the Microterm ACT 4 is included:

microterm|act4|microterm act iv,
    cr=^M, cud1=^J, ind=^J, bel=^G, am, cub1=^H,
    ed=^_, el=^^, clear=^L, cup=^T%p1%c%p2%c,
    cols#80, lines#24, cuf1=^X, cuu1=^Z, home=^],

00 032 001      \0 025  \0  \b  \0 212  \0   "  \0   m   i   c   r
020   o   t   e   r   m   |   a   c   t   4   |   m   i   c   r   o
040   t   e   r   m       a   c   t       i   v  \0  \0 001  \0  \0
060  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
100  \0  \0   P  \0 377 377 030  \0 377 377 377 377 377 377 377 377
120 377 377 377 377  \0  \0 002  \0 377 377 377 377 004  \0 006  \0
140  \b  \0 377 377 377 377  \n  \0 026  \0 030  \0 377 377 032  \0
160 377 377 377 377 034  \0 377 377 036  \0 377 377 377 377 377 377
200 377 377 377 377 377 377 377 377 377 377 377 377 377 377 377 377
*
520 377 377 377 377      \0 377 377 377 377 377 377 377 377 377 377
540 377 377 377 377 377 377 007  \0  \r  \0  \f  \0 036  \0 037  \0
560 024   %   p   1   %   c   %   p   2   %   c  \0  \n  \0 035  \0
600  \b  \0 030  \0 032  \0  \n  \0

Some limitations: total compiled entries cannot exceed 4096 bytes. The name field cannot exceed 128 bytes.

FILES
/usr/lib/terminfo/*/*    compiled terminal capability data base

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