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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
       /usr/share/misc/terminfo.   Two	configurations	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: /usr/share/misc/terminfo/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/ter-
	    minfo/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 ter-
	    minfo  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 ter-
	    minfo databases organized as a directory tree,  but	 cannot	 write
	    entries  into  the	directory tree.	 It can	write (or rewrite) en-
	    tries in the hashed	database.

	    ncurses distinguishes the two  cases  in  the  TERMINFO  and  TER-
	    MINFO_DIRS	environment  variable by assuming a directory tree for
	    entries that correspond to an existing directory, and hashed data-
	    base otherwise.

   LEGACY 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	order-
       ing or sign extension are made.

       The compiled file is created with the tic program, and read by the rou-
       tine setupterm(3X).  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*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-en-
       dian 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
       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	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	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  in-
       tact 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 capabilities.

       The ncurses libraries and applications support extended terminfo	binary
       format,	allowing users to define capabilities which are	loaded at run-
       time.  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 ac-
       cording 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 names as well as extended capability	values.

       Using the counts	and sizes, ncurses 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.  Af-
       ter  the	end of these values, it	contains the names for each of the ex-
       tended capabilities in order, e.g., booleans, then numbers and  finally
       strings.

       Applications which manipulate terminal data can use the definitions de-
       scribed in term_variables(3X) which associate the long capability names
       with members of a TERMTYPE structure.

   EXTENDED NUMBER FORMAT
       On occasion, 16-bit signed integers are not large enough.  With ncurses
       6.1, a new format was introduced	by making a few	changes	to the	legacy
       format:

       o   a different magic number (octal 01036)

       o   changing  the type for the number array from	signed 16-bit integers
	   to signed 32-bit integers.

       To maintain compatibility, the library presents the  same  data	struc-
       tures to	direct users of	the TERMTYPE structure as in previous formats.
       However,	that cannot provide callers with the  extended	numbers.   The
       library	uses  a	similar	but hidden data	structure TERMTYPE2 to provide
       data for	the terminfo functions.

PORTABILITY
   setupterm
       Note that it is possible	for setupterm to expect	a different set	of ca-
       pabilities  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 pos-
       sibilities - 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.

   Binary format
       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	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 bi-
       nary format) collide with System	V and XSI Curses extensions.  See ter-
       minfo(5)	 for  detailed discussion of terminfo source compatibility is-
       sues.

       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.

   Magic codes
       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 file 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 scr_dump(5)).  This implementation uses
       01036 as	a continuation of that sequence, but with a different high-or-
       der byte	to avoid confusion.

   The TERMTYPE	structure
       Direct access to	the TERMTYPE structure is provided for legacy applica-
       tions.	Portable  applications	should	use  the tigetflag and related
       functions described in curs_terminfo(3X)	for reading terminal capabili-
       ties.

   Mixed-case terminal names
       A  small	 number	 of  terminal descriptions use uppercase characters in
       their names.  If	the underlying filesystem ignores the  difference  be-
       tween uppercase and lowercase, ncurses represents the "first character"
       of the terminal name used as the	intermediate level of a	directory tree
       in (two-character) hexadecimal form.

EXAMPLE
       As an example, here is a	description for	the Lear-Siegler ADM-3,	a pop-
       ular 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			   ........ .

LIMITS
       Some limitations:

       o   total compiled entries cannot exceed	4096 bytes in the legacy  for-
	   mat.

       o   total  compiled  entries  cannot exceed 32768 bytes in the extended
	   format.

       o   the name field cannot exceed	128 bytes.

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

SEE ALSO
       curses(3X), terminfo(5).

AUTHORS
       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 pcurses.

								       term(5)

NAME | SYNOPSIS | DESCRIPTION | PORTABILITY | EXAMPLE | LIMITS | FILES | SEE ALSO | AUTHORS

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