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30 .\" $Id: term.5,v 1.59 2023/10/07 21:19:07 tom Exp $
31 .TH term 5 2023-10-07 "ncurses 6.4" "File formats"
54 compiled \fIterminfo\fR terminal description
59 Compiled terminfo descriptions are placed under the directory \fB\*d\fP.
60 Two configurations are supported (when building the \fBncurses\fP libraries):
63 A two-level scheme is used to avoid a linear search
64 of a huge \s-1UNIX\s+1 system directory: \fB\*d/c/name\fP where
66 is the name of the terminal, and
68 is the first character of
72 can be found in the file \fB\*d/a/act4\fP.
73 Synonyms for the same terminal are implemented by multiple
74 links to the same compiled file.
77 Using Berkeley database, two types of records are stored:
78 the terminfo data in the same format as stored in a directory tree with
79 the terminfo's primary name as a key,
80 and records containing only aliases pointing to the primary name.
82 If built to write hashed databases,
83 \fBncurses\fP can still read terminfo databases organized as a directory tree,
84 but cannot write entries into the directory tree.
85 It can write (or rewrite) entries in the hashed database.
87 \fBncurses\fP distinguishes the two cases in the TERMINFO and TERMINFO_DIRS
88 environment variable by assuming a directory tree for entries that
89 correspond to an existing directory,
90 and hashed database otherwise.
91 .SS LEGACY STORAGE FORMAT
92 The format has been chosen so that it will be the same on all hardware.
93 An 8 or more bit byte is assumed, but no assumptions about byte ordering
94 or sign extension are made.
96 The compiled file is created with the \fB@TIC@\fP program,
97 and read by the routine \fBsetupterm\fP(3X).
98 The file is divided into six parts:
103 b) \fIterminal names\fP,
105 c) \fIboolean flags\fP,
109 e) \fIstrings\fP, and
111 f) \fIstring table\fP.
114 The \fIheader\fP section begins the file.
115 This section contains six short integers in the format
120 (1) the \fImagic number\fP (octal 0432);
122 (2) the size, in bytes, of the \fIterminal names\fP section;
124 (3) the number of bytes in the \fIboolean flags\fP section;
126 (4) the number of short integers in the \fInumbers\fP section;
128 (5) the number of offsets (short integers) in the \fIstrings\fP section;
130 (6) the size, in bytes, of the \fIstring table\fP.
133 The capabilities in the
137 sections are in the same order as the file <term.h>.
139 Short integers are signed, in the range \-32768 to 32767.
140 They are stored as two 8-bit bytes.
141 The first byte contains the least significant 8 bits of the value,
142 and the second byte contains the most significant 8 bits.
143 (Thus, the value represented is 256*second+first.)
144 This format corresponds to the hardware of the \s-1VAX\s+1
145 and \s-1PDP\s+1-11 (that is, little-endian machines).
146 Machines where this does not correspond to the hardware must read the
147 integers as two bytes and compute the little-endian value.
149 Numbers in a terminal description,
150 whether they are entries in the \fInumbers\fP or \fIstrings\fP table,
151 are positive integers.
152 Boolean flags are treated as positive one-byte integers.
153 In each case, those positive integers represent a terminal capability.
154 The terminal compiler @TIC@ uses negative integers to handle the cases where
155 a capability is not available:
157 If a capability is absent from this terminal,
158 @TIC@ stores a \-1 in the corresponding table.
160 The integer value \-1 is represented by two bytes 0377, 0377.
162 Absent boolean values are represented by the byte 0 (false).
164 If a capability has been canceled from this terminal,
165 @TIC@ stores a \-2 in the corresponding table.
167 The integer value \-2 is represented by two bytes 0377, 0376.
169 The boolean value \-2 is represented by the byte 0376.
172 Other negative values are illegal.
174 The \fIterminal names\fP section comes after the \fIheader\fP.
175 It contains the first line of the terminfo description,
176 listing the various names for the terminal,
177 separated by the \*(``|\*('' character.
178 The \fIterminal names\fP section is terminated
179 with an \s-1ASCII NUL\s+1 character.
181 The \fIboolean flags\fP section has one byte for each flag.
182 Boolean capabilities are either 1 or 0 (true or false)
183 according to whether the terminal supports the given capability or not.
185 Between the \fIboolean flags\fP section and the \fInumber\fP section,
186 a null byte will be inserted, if necessary,
187 to ensure that the \fInumber\fP section begins on an even byte
188 This is a relic of the PDP\-11's word-addressed architecture,
189 originally designed to avoid traps induced
190 by addressing a word on an odd byte boundary.
191 All short integers are aligned on a short word boundary.
193 The \fInumbers\fP section is similar to the \fIboolean flags\fP section.
194 Each capability takes up two bytes,
195 and is stored as a little-endian short integer.
197 The \fIstrings\fP section is also similar.
198 Each capability is stored as a short integer.
199 The capability value is an index into the \fIstring table\fP.
201 The \fIstring table\fP is the last section.
202 It contains all of the values of string capabilities referenced in
203 the \fIstrings\fP section.
204 Each string is null-terminated.
205 Special characters in \*^X or \ec notation are stored in their
206 interpreted form, not the printing representation.
207 Padding information $<nn> and parameter information %x are
208 stored intact in uninterpreted form.
209 .SS EXTENDED STORAGE FORMAT
210 The previous section describes the conventional terminfo binary format.
211 With some minor variations of the offsets (see PORTABILITY),
212 the same binary format is used in all modern UNIX systems.
213 Each system uses a predefined set of boolean, number or string capabilities.
215 The \fBncurses\fP libraries and applications support
216 extended terminfo binary format,
217 allowing users to define capabilities which are loaded at runtime.
219 extension is made possible by using the fact that the other implementations
220 stop reading the terminfo data when they have reached the end of the size given
222 \fBncurses\fP checks the size,
223 and if it exceeds that due to the predefined data,
224 continues to parse according to its own scheme.
226 First, it reads the extended header (5 short integers):
230 count of extended boolean capabilities
233 count of extended numeric capabilities
236 count of extended string capabilities
239 count of the items in extended string table
242 size of the extended string table in bytes
245 The count- and size-values for the extended string table
246 include the extended capability \fInames\fP as well as
247 extended capability \fIvalues\fP.
249 Using the counts and sizes, \fBncurses\fP allocates arrays and reads data
250 for the extended capabilities in the same order as the header information.
252 The extended string table contains values for string capabilities.
253 After the end of these values, it contains the names for each of
254 the extended capabilities in order, e.g., booleans, then numbers and
257 Applications which manipulate terminal data can use the definitions
258 described in \fBterm_variables\fP(3X) which associate the long capability
259 names with members of a \fBTERMTYPE\fP structure.
261 .SS EXTENDED NUMBER FORMAT
262 On occasion, 16-bit signed integers are not large enough.
263 With \fBncurses\fP 6.1, a new format was introduced by making a few changes
264 to the legacy format:
266 a different magic number (octal 01036)
268 changing the type for the \fInumber\fP array from signed 16-bit integers
269 to signed 32-bit integers.
271 To maintain compatibility, the library presents the same data structures
272 to direct users of the \fBTERMTYPE\fP structure as in previous formats.
273 However, that cannot provide callers with the extended numbers.
274 The library uses a similar but hidden data structure \fBTERMTYPE2\fP
275 to provide data for the terminfo functions.
278 Note that it is possible for
280 to expect a different set of capabilities
281 than are actually present in the file.
282 Either the database may have been updated since
285 (resulting in extra unrecognized entries in the file)
286 or the program may have been recompiled more recently
287 than the database was updated
288 (resulting in missing entries).
291 must be prepared for both possibilities \-
292 this is why the numbers and sizes are included.
293 Also, new capabilities must always be added at the end of the lists
294 of boolean, number, and string capabilities.
296 X/Open Curses does not specify a format for the terminfo database.
297 UNIX System V curses used a directory-tree of binary files,
298 one per terminal description.
300 Despite the consistent use of little-endian for numbers and the otherwise
301 self-describing format, it is not wise to count on portability of binary
302 terminfo entries between commercial UNIX versions.
303 The problem is that there
304 are at least three versions of terminfo (under HP\-UX, AIX, and OSF/1) which
305 diverged from System V terminfo after SVr1, and have added extension
306 capabilities to the string table that (in the binary format) collide with
307 System V and XSI Curses extensions.
308 See \fBterminfo\fP(\*n) for detailed
309 discussion of terminfo source compatibility issues.
311 This implementation is by default compatible with the binary
312 terminfo format used by Solaris curses,
313 except in a few less-used details
314 where it was found that the latter did not match X/Open Curses.
315 The format used by the other Unix versions
316 can be matched by building ncurses
317 with different configuration options.
319 The magic number in a binary terminfo file is the first 16-bits (two bytes).
320 Besides making it more reliable for the library to check that a file
322 utilities such as \fBfile\fP(1) also use that to tell what the file-format is.
323 System V defined more than one magic number,
324 with 0433, 0435 as screen-dumps (see \fBscr_dump\fP(5)).
325 This implementation uses 01036 as a continuation of that sequence,
326 but with a different high-order byte to avoid confusion.
327 .SS The TERMTYPE structure
328 Direct access to the \fBTERMTYPE\fP structure is provided for legacy
330 Portable applications should use the \fBtigetflag\fP and related functions
331 described in \fBcurs_terminfo\fP(3X) for reading terminal capabilities.
332 .SS Mixed-case terminal names
333 A small number of terminal descriptions use uppercase characters in
335 If the underlying filesystem ignores the difference between
336 uppercase and lowercase,
337 \fBncurses\fP represents the \*(``first character\*(''
338 of the terminal name used as
339 the intermediate level of a directory tree in (two-character) hexadecimal form.
341 As an example, here is a description for the Lear-Siegler
342 ADM\-3, a popular though rather stupid early terminal:
349 bel=\*^G, clear=\e032$<1>, cr=\*^M, cub1=\*^H, cud1=\*^J,
350 cuf1=\*^L, cup=\eE=%p1%{32}%+%c%p2%{32}%+%c, cuu1=\*^K,
351 home=\*^\*^, ind=\*^J,
355 and a hexadecimal dump of the compiled terminal description:
361 0000 1a 01 10 00 02 00 03 00 82 00 31 00 61 64 6d 33 ........ ..1.adm3
362 0010 61 7c 6c 73 69 20 61 64 6d 33 61 00 00 01 50 00 a|lsi ad m3a...P.
363 0020 ff ff 18 00 ff ff 00 00 02 00 ff ff ff ff 04 00 ........ ........
364 0030 ff ff ff ff ff ff ff ff 0a 00 25 00 27 00 ff ff ........ ..%.'...
365 0040 29 00 ff ff ff ff 2b 00 ff ff 2d 00 ff ff ff ff ).....+. ..-.....
366 0050 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
367 0060 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
368 0070 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
369 0080 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
370 0090 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
371 00a0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
372 00b0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
373 00c0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
374 00d0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
375 00e0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
376 00f0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
377 0100 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
378 0110 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
379 0120 ff ff ff ff ff ff 2f 00 07 00 0d 00 1a 24 3c 31 ....../. .....$<1
380 0130 3e 00 1b 3d 25 70 31 25 7b 33 32 7d 25 2b 25 63 >..=%p1% {32}%+%c
381 0140 25 70 32 25 7b 33 32 7d 25 2b 25 63 00 0a 00 1e %p2%{32} %+%c....
382 0150 00 08 00 0c 00 0b 00 0a 00 ........ .
388 total compiled entries cannot exceed 4096 bytes in the legacy format.
390 total compiled entries cannot exceed 32768 bytes in the extended format.
392 the name field cannot exceed 128 bytes.
394 Compiled entries are limited to 32768 bytes because offsets into the
395 \fIstrings table\fP use two-byte integers.
396 The legacy format could have supported 32768-byte entries,
397 but was limited a virtual memory page's 4096 bytes.
399 \*d/*/* compiled terminal capability database
403 extended terminfo format for ncurses 5.0
405 hashed database support for ncurses 5.6
407 extended number support for ncurses 6.1
411 documented legacy terminfo format, e.g., from \fIpcurses\fP.
414 \fB\%curs_terminfo\fP(3X),
415 \fB\%terminfo\fP(\*n)