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43 <H1 class="no-header">term 5 2024-04-20 ncurses 6.4 File formats</H1>
45 <STRONG><A HREF="term.5.html">term(5)</A></STRONG> File formats <STRONG><A HREF="term.5.html">term(5)</A></STRONG>
50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
51 term - compiled <EM>terminfo</EM> terminal description
54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
58 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
60 </PRE><H3><a name="h3-Storage-Location">Storage Location</a></H3><PRE>
61 Compiled terminfo descriptions are placed under the directory
62 <STRONG>/usr/share/terminfo</STRONG>. Two configurations are supported (when building
63 the <EM>ncurses</EM> libraries):
65 <STRONG>directory</STRONG> <STRONG>tree</STRONG>
66 A two-level scheme is used to avoid a linear search of a huge Unix
67 system directory: <STRONG>/usr/share/terminfo/c/name</STRONG> where <EM>name</EM> is the
68 name of the terminal, and <EM>c</EM> is the first character of <EM>name</EM>. Thus,
69 <EM>act4</EM> can be found in the file <STRONG>/usr/share/terminfo/a/act4</STRONG>.
70 Synonyms for the same terminal are implemented by multiple links
71 to the same compiled file.
73 <STRONG>hashed</STRONG> <STRONG>database</STRONG>
74 Using Berkeley database, two types of records are stored: the
75 terminfo data in the same format as stored in a directory tree
76 with the terminfo's primary name as a key, and records containing
77 only aliases pointing to the primary name.
79 If built to write hashed databases, <EM>ncurses</EM> can still read
80 terminfo databases organized as a directory tree, but cannot write
81 entries into the directory tree. It can write (or rewrite)
82 entries in the hashed database.
84 <EM>ncurses</EM> distinguishes the two cases in the <EM>TERMINFO</EM> and
85 <EM>TERMINFO</EM><STRONG>_</STRONG><EM>DIRS</EM> environment variable by assuming a directory tree
86 for entries that correspond to an existing directory, and hashed
90 </PRE><H3><a name="h3-Legacy-Storage-Format">Legacy Storage Format</a></H3><PRE>
91 The format has been chosen so that it will be the same on all hardware.
92 An 8 or more bit byte is assumed, but no assumptions about byte
93 ordering or sign extension are made.
95 The compiled file is created with the <STRONG>tic</STRONG> program, and read by the
96 routine <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG>. The file is divided into six parts:
100 b) <EM>terminal</EM> <EM>names</EM>,
102 c) <EM>Boolean</EM> <EM>flags</EM>,
106 e) <EM>strings</EM>, and
108 f) <EM>string</EM> <EM>table</EM>.
110 The <EM>header</EM> section begins the file. This section contains six short
111 integers in the format described below. These integers are
113 (1) the <EM>magic</EM> <EM>number</EM> (octal 0432);
115 (2) the size, in bytes, of the <EM>terminal</EM> <EM>names</EM> section;
117 (3) the number of bytes in the <EM>Boolean</EM> <EM>flags</EM> section;
119 (4) the number of short integers in the <EM>numbers</EM> section;
121 (5) the number of offsets (short integers) in the <EM>strings</EM> section;
123 (6) the size, in bytes, of the <EM>string</EM> <EM>table</EM>.
125 The capabilities in the <EM>Boolean</EM> <EM>flags</EM>, <EM>numbers</EM>, and <EM>strings</EM> sections
126 are in the same order as the file <term.h>.
128 Short integers are signed, in the range -32768 to 32767. They are
129 stored as two 8-bit bytes. The first byte contains the least
130 significant 8 bits of the value, and the second byte contains the most
131 significant 8 bits. (Thus, the value represented is 256*second+first.)
132 This format corresponds to the hardware of the VAX and PDP-11 (that is,
133 little-endian machines). Machines where this does not correspond to
134 the hardware must read the integers as two bytes and compute the
137 Numbers in a terminal description, whether they are entries in the
138 <EM>numbers</EM> or <EM>strings</EM> table, are positive integers. Boolean flags are
139 treated as positive one-byte integers. In each case, those positive
140 integers represent a terminal capability. The terminal compiler tic
141 uses negative integers to handle the cases where a capability is not
144 <STRONG>o</STRONG> If a capability is absent from this terminal, tic stores a -1 in
145 the corresponding table.
147 The integer value -1 is represented by two bytes 0377, 0377.
148 Absent Boolean values are represented by the byte 0 (false).
150 <STRONG>o</STRONG> If a capability has been canceled from this terminal, tic stores a
151 -2 in the corresponding table.
153 The integer value -2 is represented by two bytes 0377, 0376.
154 The Boolean value -2 is represented by the byte 0376.
156 <STRONG>o</STRONG> Other negative values are illegal.
158 The <EM>terminal</EM> <EM>names</EM> section comes after the <EM>header</EM>. It contains the
159 first line of the terminfo description, listing the various names for
160 the terminal, separated by the "|" character. The <EM>terminal</EM> <EM>names</EM>
161 section is terminated with an ASCII NUL character.
163 The <EM>Boolean</EM> <EM>flags</EM> section has one byte for each flag. Boolean
164 capabilities are either 1 or 0 (true or false) according to whether the
165 terminal supports the given capability or not.
167 Between the <EM>Boolean</EM> <EM>flags</EM> section and the <EM>number</EM> section, a null byte
168 will be inserted, if necessary, to ensure that the <EM>number</EM> section
169 begins on an even byte This is a relic of the PDP-11's word-addressed
170 architecture, originally designed to avoid traps induced by addressing
171 a word on an odd byte boundary. All short integers are aligned on a
174 The <EM>numbers</EM> section is similar to the <EM>Boolean</EM> <EM>flags</EM> section. Each
175 capability takes up two bytes, and is stored as a little-endian short
178 The <EM>strings</EM> section is also similar. Each capability is stored as a
179 short integer. The capability value is an index into the <EM>string</EM> <EM>table</EM>.
181 The <EM>string</EM> <EM>table</EM> is the last section. It contains all of the values of
182 string capabilities referenced in the <EM>strings</EM> section. Each string is
183 null-terminated. Special characters in ^X or \c notation are stored in
184 their interpreted form, not the printing representation. Padding
185 information $<nn> and parameter information %x are stored intact in
189 </PRE><H3><a name="h3-Extended-Storage-Format">Extended Storage Format</a></H3><PRE>
190 The previous section describes the conventional terminfo binary format.
191 With some minor variations of the offsets (see PORTABILITY), the same
192 binary format is used in all modern Unix systems. Each system uses a
193 predefined set of Boolean, number or string capabilities.
195 The <EM>ncurses</EM> libraries and applications support extended terminfo binary
196 format, allowing users to define capabilities which are loaded at
197 runtime. This extension is made possible by using the fact that the
198 other implementations stop reading the terminfo data when they have
199 reached the end of the size given in the header. <EM>ncurses</EM> checks the
200 size, and if it exceeds that due to the predefined data, continues to
201 parse according to its own scheme.
203 First, it reads the extended header (5 short integers):
205 (1) count of extended Boolean capabilities
207 (2) count of extended numeric capabilities
209 (3) count of extended string capabilities
211 (4) count of the items in extended string table
213 (5) size of the extended string table in bytes
215 The count- and size-values for the extended string table include the
216 extended capability <EM>names</EM> as well as extended capability <EM>values</EM>.
218 Using the counts and sizes, <EM>ncurses</EM> allocates arrays and reads data for
219 the extended capabilities in the same order as the header information.
221 The extended string table contains values for string capabilities.
222 After the end of these values, it contains the names for each of the
223 extended capabilities in order, e.g., Booleans, then numbers and
226 By storing terminal descriptions in this way, <EM>ncurses</EM> is able to
227 provide a database useful with legacy applications, as well as
228 providing data for applications which need more than the predefined
229 capabilities. See <STRONG><A HREF="user_caps.5.html">user_caps(5)</A></STRONG> for an overview of the way <EM>ncurses</EM> uses
230 this extended information.
232 Applications which manipulate terminal data can use the definitions
233 described in <STRONG><A HREF="term_variables.3x.html">term_variables(3x)</A></STRONG> which associate the long capability
234 names with members of a <STRONG>TERMTYPE</STRONG> structure.
237 </PRE><H3><a name="h3-Extended-Number-Format">Extended Number Format</a></H3><PRE>
238 On occasion, 16-bit signed integers are not large enough. With <EM>ncurses</EM>
239 6.1, a new format was introduced by making a few changes to the legacy
242 <STRONG>o</STRONG> a different magic number (octal 01036)
244 <STRONG>o</STRONG> changing the type for the <EM>number</EM> array from signed 16-bit integers
245 to signed 32-bit integers.
247 To maintain compatibility, the library presents the same data
248 structures to direct users of the <STRONG>TERMTYPE</STRONG> structure as in previous
249 formats. However, that cannot provide callers with the extended
250 numbers. The library uses a similar but hidden data structure
251 <STRONG>TERMTYPE2</STRONG> to provide data for the terminfo functions.
254 </PRE><H2><a name="h2-FILES">FILES</a></H2><PRE>
255 <EM>/usr/share/terminfo</EM>
256 compiled terminal description database
259 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
261 </PRE><H3><a name="h3-setupterm">setupterm</a></H3><PRE>
262 Note that it is possible for <STRONG>setupterm</STRONG> to expect a different set of
263 capabilities than are actually present in the file. Either the
264 database may have been updated since <STRONG>setupterm</STRONG> was recompiled
265 (resulting in extra unrecognized entries in the file) or the program
266 may have been recompiled more recently than the database was updated
267 (resulting in missing entries). The routine <STRONG>setupterm</STRONG> must be prepared
268 for both possibilities - this is why the numbers and sizes are
269 included. Also, new capabilities must always be added at the end of
270 the lists of Boolean, number, and string capabilities.
273 </PRE><H3><a name="h3-Binary-Format">Binary Format</a></H3><PRE>
274 X/Open Curses does not specify a format for the terminfo database.
275 System V curses used a directory-tree of binary files, one per terminal
278 Despite the consistent use of little-endian for numbers and the
279 otherwise self-describing format, it is not wise to count on
280 portability of binary terminfo entries between commercial Unix
281 versions. The problem is that there are at least three versions of
282 terminfo (under HP-UX, AIX, and OSF/1) which diverged from System V
283 terminfo after SVr1, and have added extension capabilities to the
284 string table that (in the binary format) collide with System V and
285 X/Open Curses extensions. See <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG> for detailed discussion of
286 terminfo source compatibility issues.
288 This implementation is by default compatible with the binary terminfo
289 format used by Solaris curses, except in a few less-used details where
290 it was found that the latter did not match X/Open Curses. The format
291 used by the other Unix versions can be matched by building <EM>ncurses</EM> with
292 different configuration options.
295 </PRE><H3><a name="h3-Magic-Codes">Magic Codes</a></H3><PRE>
296 The magic number in a binary terminfo file is the first 16-bits (two
297 bytes). Besides making it more reliable for the library to check that
298 a file is terminfo, utilities such as <STRONG>file(1)</STRONG> also use that to tell
299 what the file-format is. System V defined more than one magic number,
300 with 0433, 0435 as screen-dumps (see <STRONG><A HREF="scr_dump.5.html">scr_dump(5)</A></STRONG>). This implementation
301 uses 01036 as a continuation of that sequence, but with a different
302 high-order byte to avoid confusion.
304 <STRONG>The</STRONG> <EM>TERMTYPE</EM> <STRONG>Structure</STRONG>
305 Direct access to the <STRONG>TERMTYPE</STRONG> structure is provided for legacy
306 applications. Portable applications should use the <STRONG>tigetflag</STRONG> and
307 related functions described in <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG> for reading terminal
311 </PRE><H3><a name="h3-Mixed-case-Terminal-Names">Mixed-case Terminal Names</a></H3><PRE>
312 A small number of terminal descriptions use uppercase characters in
313 their names. If the underlying filesystem ignores the difference
314 between uppercase and lowercase, <EM>ncurses</EM> represents the "first
315 character" of the terminal name used as the intermediate level of a
316 directory tree in (two-character) hexadecimal form.
319 </PRE><H3><a name="h3-Limits">Limits</a></H3><PRE>
320 <EM>ncurses</EM> stores compiled terminal descriptions in three related formats,
321 described in the sections
323 <STRONG>o</STRONG> <STRONG>LEGACY</STRONG> <STRONG>STORAGE</STRONG> <STRONG>FORMAT</STRONG>, and
325 <STRONG>o</STRONG> <STRONG>EXTENDED</STRONG> <STRONG>STORAGE</STRONG> <STRONG>FORMAT</STRONG>, and
327 <STRONG>o</STRONG> <STRONG>EXTENDED</STRONG> <STRONG>NUMBER</STRONG> <STRONG>FORMAT</STRONG>.
329 The legacy storage format and the extended number format differ by the
330 types of numeric capability which they can store (i.e., 16-bit versus
331 32-bit integers). The extended storage format introduced by <EM>ncurses</EM>
332 5.0 adds data to either of these formats.
334 Some limitations apply:
336 <STRONG>o</STRONG> total compiled entries cannot exceed 4096 bytes in the legacy
339 <STRONG>o</STRONG> total compiled entries cannot exceed 32768 bytes in the extended
342 <STRONG>o</STRONG> the name field cannot exceed 128 bytes.
344 Compiled entries are limited to 32768 bytes because offsets into the
345 <EM>strings</EM> <EM>table</EM> use two-byte integers. The legacy format could have
346 supported 32768-byte entries, but was limited to a virtual memory
350 </PRE><H2><a name="h2-EXAMPLES">EXAMPLES</a></H2><PRE>
351 As an example, here is a description for the Lear-Siegler ADM-3, a
352 popular though rather stupid early terminal:
357 bel=^G, clear=\032$<1>, cr=^M, cub1=^H, cud1=^J,
358 cuf1=^L, cup=\E=%p1%{32}%+%c%p2%{32}%+%c, cuu1=^K,
361 and a hexadecimal dump of the compiled terminal description:
363 0000 1a 01 10 00 02 00 03 00 82 00 31 00 61 64 6d 33 ........ ..1.adm3
364 0010 61 7c 6c 73 69 20 61 64 6d 33 61 00 00 01 50 00 a|lsi ad m3a...P.
365 0020 ff ff 18 00 ff ff 00 00 02 00 ff ff ff ff 04 00 ........ ........
366 0030 ff ff ff ff ff ff ff ff 0a 00 25 00 27 00 ff ff ........ ..%.'...
367 0040 29 00 ff ff ff ff 2b 00 ff ff 2d 00 ff ff ff ff ).....+. ..-.....
368 0050 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
369 0060 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
370 0070 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
371 0080 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
372 0090 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
373 00a0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
374 00b0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
375 00c0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
376 00d0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
377 00e0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
378 00f0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
379 0100 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
380 0110 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ........ ........
381 0120 ff ff ff ff ff ff 2f 00 07 00 0d 00 1a 24 3c 31 ....../. .....$<1
382 0130 3e 00 1b 3d 25 70 31 25 7b 33 32 7d 25 2b 25 63 >..=%p1% {32}%+%c
383 0140 25 70 32 25 7b 33 32 7d 25 2b 25 63 00 0a 00 1e %p2%{32} %+%c....
384 0150 00 08 00 0c 00 0b 00 0a 00 ........ .
387 </PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
389 extended terminfo format for <EM>ncurses</EM> 5.0
390 hashed database support for <EM>ncurses</EM> 5.6
391 extended number support for <EM>ncurses</EM> 6.1
394 documented legacy terminfo format, e.g., from <EM>pcurses</EM>.
397 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
398 <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>, <STRONG><A HREF="user_caps.5.html">user_caps(5)</A></STRONG>
402 ncurses 6.4 2024-04-20 <STRONG><A HREF="term.5.html">term(5)</A></STRONG>
406 <li><a href="#h2-NAME">NAME</a></li>
407 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
408 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
410 <li><a href="#h3-Storage-Location">Storage Location</a></li>
411 <li><a href="#h3-Legacy-Storage-Format">Legacy Storage Format</a></li>
412 <li><a href="#h3-Extended-Storage-Format">Extended Storage Format</a></li>
413 <li><a href="#h3-Extended-Number-Format">Extended Number Format</a></li>
416 <li><a href="#h2-FILES">FILES</a></li>
417 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
419 <li><a href="#h3-setupterm">setupterm</a></li>
420 <li><a href="#h3-Binary-Format">Binary Format</a></li>
421 <li><a href="#h3-Magic-Codes">Magic Codes</a></li>
422 <li><a href="#h3-Mixed-case-Terminal-Names">Mixed-case Terminal Names</a></li>
423 <li><a href="#h3-Limits">Limits</a></li>
426 <li><a href="#h2-EXAMPLES">EXAMPLES</a></li>
427 <li><a href="#h2-AUTHORS">AUTHORS</a></li>
428 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>