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term(5)

NAME

       term - format of compiled term file.

SYNOPSIS

       term

DESCRIPTION

       Compiled   terminfo   descriptions   are  placed  under	the  directory
       /usr/share/misc/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/misc/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	order-
       ing or sign extension are made.

       The compiled file is created with the tic program, and read by the rou-
       tine setupterm.	The file is divided into six parts: the header, termi-
       nal 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 sec-
       tion; (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*sec-
       ond+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, lit-
       tle-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 <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
       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 begin-
       ning  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 data-
       base may have been updated since setupterm has been recompiled (result-
       ing  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	other-
       wise  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=\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  ........ ........
       name field cannot exceed 128 bytes.

FILES

       /usr/share/misc/terminfo/*/*  compiled terminal capability data base

SEE ALSO

       curses(3X), terminfo(5).

								       TERM(5)

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