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31 * @Id: user_caps.5,v 1.51 2024/06/08 21:01:53 tom Exp @
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43 <H1 class="no-header">user_caps 5 2024-06-08 ncurses 6.5 File formats</H1>
45 <STRONG><A HREF="user_caps.5.html">user_caps(5)</A></STRONG> File formats <STRONG><A HREF="user_caps.5.html">user_caps(5)</A></STRONG>
50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
51 user_caps - user-defined <EM>terminfo</EM> capability format
54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
55 <STRONG>infocmp</STRONG> <STRONG>-x</STRONG>
57 <STRONG>tic</STRONG> <STRONG>-x</STRONG>
60 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
62 </PRE><H3><a name="h3-Background">Background</a></H3><PRE>
63 Before <EM>ncurses</EM> 5.0, terminfo databases used a <EM>fixed</EM> <EM>repertoire</EM> of
64 terminal capabilities designed for the SVr2 terminal database in 1984,
65 and extended in stages through SVr4 (1989), and standardized in X/Open
66 Curses starting in 1995.
68 Most of the <EM>extensions</EM> in this fixed repertoire were additions to the
69 tables of Boolean, numeric and string capabilities. Rather than change
70 the meaning of an existing capability, a new name was added. The
71 terminfo database uses a binary format; binary compatibility was
72 ensured by using a header which gave the number of items in the tables
73 for each type of capability. The standardization was incomplete:
75 <STRONG>o</STRONG> The <EM>binary</EM> <EM>format</EM> itself is not described in the X/Open Curses
76 documentation. Only the <EM>source</EM> <EM>format</EM> is described.
78 Library developers rely upon the SVr4 documentation, and reverse-
79 engineering the compiled terminfo files to match the binary format.
81 <STRONG>o</STRONG> Lacking a standard for the binary format, most implementations copy
82 the SVr2 binary format, which uses 16-bit signed integers, and is
83 limited to 4096-byte entries.
85 The format cannot represent very large numeric capabilities, nor
86 can it represent large numbers of special keyboard definitions.
88 <STRONG>o</STRONG> The tables of capability names differ between implementations.
90 Although they <EM>may</EM> provide all of the standard capability names, the
91 position in the tables differs because some features were added as
92 needed, while others were added (out of order) to comply with
95 While <EM>ncurses</EM>' repertoire of predefined capabilities is closest to
96 Solaris, Solaris's terminfo database has a few differences from the
97 list published by X/Open Curses. For example, <EM>ncurses</EM> can be
98 configured with tables which match the terminal databases for AIX,
99 HP-UX or OSF/1, rather than the default Solaris-like configuration.
101 <STRONG>o</STRONG> In SVr4 curses and <EM>ncurses</EM>, the terminal database is defined at
102 compile-time using a text file which lists the different terminal
105 In principle, the text-file can be extended, but doing this
106 requires recompiling and reinstalling the library. The text-file
107 used in <EM>ncurses</EM> for terminal capabilities includes details for
108 various systems past the documented X/Open Curses features. For
109 example, <EM>ncurses</EM> supports these capabilities in each configuration:
112 (meml) lock memory above cursor
118 (box1) box characters primary set
120 The memory lock/unlock capabilities were included because they were
121 used in the X11R6 terminal description for <STRONG>xterm(1)</STRONG>. The <EM>box1</EM>
122 capability is used in tic to help with terminal descriptions
125 During the 1990s, some users were reluctant to use terminfo in spite of
126 its performance advantages over termcap:
128 <STRONG>o</STRONG> The fixed repertoire prevented users from adding features for
129 unanticipated terminal improvements (or required them to reuse
130 existing capabilities as a workaround).
132 <STRONG>o</STRONG> The limitation to 16-bit signed integers was also mentioned.
133 Because termcap stores everything as a string, it could represent
136 Although termcap's extensibility was rarely used (it was never the
137 <EM>speaker</EM> who had actually used the feature), the criticism had a point.
138 <EM>ncurses</EM> 5.0 provided a way to detect nonstandard capabilities,
139 determine their type and optionally store and retrieve them in a way
140 which did not interfere with other applications. These are referred to
141 as <EM>user-defined</EM> <EM>capabilities</EM> because no modifications to the toolset's
142 predefined capability names are needed.
144 The <EM>ncurses</EM> utilities <STRONG>tic</STRONG> and <STRONG>infocmp</STRONG> have a command-line option "-x"
145 to control whether the nonstandard capabilities are stored or
146 retrieved. A library function <STRONG>use_extended_names</STRONG> is provided for the
149 When compiling a terminal database, if "-x" is set, <STRONG>tic</STRONG> will store a
150 user-defined capability if the capability name is not one of the
153 Because <EM>ncurses</EM> provides a termcap library interface, these user-
154 defined capabilities may be visible to termcap applications:
156 <STRONG>o</STRONG> The termcap interface (like all implementations of termcap)
157 requires that the capability names are 2-characters.
159 When the capability is simple enough for use in a termcap
160 application, it is provided as a 2-character name.
162 <STRONG>o</STRONG> There are other user-defined capabilities which refer to features
163 not usable in termcap, e.g., parameterized strings that use more
164 than two parameters or use more than the trivial expression support
165 provided by termcap. For these, the terminfo database should have
166 only capability names with 3 or more characters.
168 <STRONG>o</STRONG> Some terminals can send distinct strings for special keys (cursor-,
169 keypad- or function-keys) depending on modifier keys (shift,
170 control, etc.). While terminfo and termcap have a set of 60
171 predefined function-key names, to which a series of keys can be
172 assigned, that is insufficient for more than a dozen keys
173 multiplied by more than a couple of modifier combinations. The
174 <EM>ncurses</EM> database uses a convention based on <STRONG>xterm(1)</STRONG> to provide
175 extended special-key names.
177 Fitting that into termcap's limitation of 2-character names would
178 be pointless. These extended keys are available only with
182 </PRE><H3><a name="h3-Recognized-Capabilities">Recognized Capabilities</a></H3><PRE>
183 The <EM>ncurses</EM> library uses the user-definable capabilities. While the
184 terminfo database may have other extensions, <EM>ncurses</EM> makes explicit
187 AX <EM>Boolean</EM>, asserts that the terminal interprets SGR 39 and SGR 49
188 by resetting the foreground and background color, respectively,
191 This is a feature recognized by the <STRONG>screen</STRONG> program as well.
193 E3 <EM>string</EM>, tells how to clear the terminal's scrollback buffer.
194 When present, the <STRONG><A HREF="clear.1.html">clear(1)</A></STRONG> program sends this before clearing the
197 The command "<STRONG>tput</STRONG> <STRONG>clear</STRONG>" does the same thing.
199 NQ <EM>Boolean</EM>, used to suppress a consistency check in tic for the
200 <EM>ncurses</EM> capabilities in user6 through user9 (u6, u7, u8 and u9)
201 which tell how to query the terminal's cursor position and its
205 <EM>Boolean</EM>, <EM>number</EM> <STRONG>or</STRONG> <EM>string</EM>, used to assert that the
206 <STRONG>set_a_foreground</STRONG> and <STRONG>set_a_background</STRONG> capabilities correspond to
207 <EM>direct</EM> <EM>colors</EM>, using an RGB (red/green/blue) convention. This
208 capability allows the <STRONG>color_content</STRONG> function to return
209 appropriate values without requiring the application to
210 initialize colors using <STRONG>init_color</STRONG>.
212 The capability type determines the values which <EM>ncurses</EM> sees:
215 implies that the number of bits for red, green and blue are
216 the same. Using the maximum number of colors, <EM>ncurses</EM> adds
217 two, divides that sum by three, and assigns the result to red,
218 green and blue in that order.
220 If the number of bits needed for the number of colors is not a
221 multiple of three, the blue (and green) components lose in
225 tells <EM>ncurses</EM> what result to add to red, green and blue. If
226 <EM>ncurses</EM> runs out of bits, blue (and green) lose just as in the
227 <EM>Boolean</EM> case.
230 explicitly list the number of bits used for red, green and
231 blue components as a slash-separated list of decimal integers.
233 Because there are several RGB encodings in use, applications
234 which make assumptions about the number of bits per color are
235 unlikely to work reliably. As a trivial case, for example, one
236 could define <STRONG>RGB#1</STRONG> to represent the standard eight ANSI colors,
237 i.e., one bit per color.
239 U8 <EM>number</EM>, asserts that <EM>ncurses</EM> must use Unicode values for line-
240 drawing characters, and that it should ignore the alternate
241 character set capabilities when the locale uses UTF-8 encoding.
242 For more information, see the discussion of <STRONG>NCURSES_NO_UTF8_ACS</STRONG>
243 in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>.
245 Set this capability to a nonzero value to enable it.
247 XM <EM>string</EM>, override <EM>ncurses</EM>'s built-in string which enables/disables
248 <STRONG>xterm(1)</STRONG> mouse mode.
250 <EM>ncurses</EM> sends a character sequence to the terminal to initialize
251 mouse mode, and when the user clicks the mouse buttons or (in
252 certain modes) moves the mouse, handles the characters sent back
253 by the terminal to tell it what was done with the mouse.
255 The mouse protocol is enabled when the <EM>mask</EM> passed in the
256 <STRONG>mousemask</STRONG> function is nonzero. By default, <EM>ncurses</EM> handles the
257 responses for the X11 xterm mouse protocol. It also knows about
258 the <EM>SGR</EM> <EM>1006</EM> xterm mouse protocol, but must to be told to look
259 for this specifically. It will not be able to guess which mode
260 is used, because the responses are enough alike that only
261 confusion would result.
263 The <STRONG>XM</STRONG> capability has a single parameter. If nonzero, the mouse
264 protocol should be enabled. If zero, the mouse protocol should
265 be disabled. <EM>ncurses</EM> inspects this capability if it is present,
266 to see whether the 1006 protocol is used. If so, it expects the
267 responses to use the <EM>SGR</EM> <EM>1006</EM> xterm mouse protocol.
269 The xterm mouse protocol is used by other terminal emulators.
270 The terminal database uses building-blocks for the various xterm
271 mouse protocols which can be used in customized terminal
274 The terminal database building blocks for this mouse feature also
275 have an experimental capability <EM>xm</EM>. The "xm" capability
276 describes the mouse response. Currently there is no interpreter
277 which would use this information to make the mouse support
278 completely data-driven.
280 <EM>xm</EM> shows the format of the mouse responses. In this experimental
281 capability, the parameters are
283 <EM>p1</EM> y-ordinate
285 <EM>p2</EM> x-ordinate
289 <EM>p4</EM> state, e.g., pressed or released
291 <EM>p5</EM> y-ordinate starting region
293 <EM>p6</EM> x-ordinate starting region
295 <EM>p7</EM> y-ordinate ending region
297 <EM>p8</EM> x-ordinate ending region
299 Here are examples from the terminal database for the most
300 commonly used xterm mouse protocols:
302 xterm+x11mouse|X11 xterm mouse protocol,
303 kmous=\E[M, XM=\E[?1000%?%p1%{1}%=%th%el%;,
305 %?%p4%t%p3%e%{3}%;%' '%+%c
309 xterm+sm+1006|xterm SGR-mouse,
310 kmous=\E[<, XM=\E[?1006;1000%?%p1%{1}%=%th%el%;,
317 </PRE><H3><a name="h3-Extended-Key-Definitions">Extended Key Definitions</a></H3><PRE>
318 Several terminals provide the ability to send distinct strings for
319 combinations of modified special keys. There is no standard for what
322 Since 1999, <STRONG>xterm(1)</STRONG> has supported <EM>shift</EM>, <EM>control</EM>, <EM>alt</EM>, and <EM>meta</EM>
323 modifiers which produce distinct special-key strings. In a terminal
324 description, <EM>ncurses</EM> has no special knowledge of the modifiers used.
325 Applications can use the <EM>naming</EM> <EM>convention</EM> established for <STRONG>xterm</STRONG> to
326 find these special keys in the terminal description.
328 Starting with the <EM>curses</EM> convention that capability codes describing
329 the input generated by a terminal's key caps begin with "k", and that
330 shifted special keys use uppercase letters in their names, <EM>ncurses</EM>'s
331 terminal database defines the following names and codes to which a
334 <STRONG>Code</STRONG> <STRONG>Description</STRONG>
335 -------------------------------------------------------------------
336 <STRONG>kDC</STRONG> shifted kdch1 (delete character)
337 <STRONG>kDN</STRONG> shifted kcud1 (cursor down)
338 <STRONG>kEND</STRONG> shifted kend (end)
339 <STRONG>kHOM</STRONG> shifted khome (home)
340 <STRONG>kLFT</STRONG> shifted kcub1 (cursor back)
341 <STRONG>kNXT</STRONG> shifted knext (next)
342 <STRONG>kPRV</STRONG> shifted kprev (previous)
343 <STRONG>kRIT</STRONG> shifted kcuf1 (cursor forward)
344 <STRONG>kUP</STRONG> shifted kcuu1 (cursor up)
346 Keycap nomenclature on the Unix systems for which <EM>curses</EM> was developed
347 differs from today's ubiquitous descendants of the IBM PC/AT keyboard
348 layout. In the foregoing, interpret "backward" as "left", "forward" as
349 "right", "next" as "page down", and "prev(ious)" as "page up".
351 These are the suffixes used to denote the modifiers:
353 <STRONG>Value</STRONG> <STRONG>Description</STRONG>
354 ----------------------------------
361 8 Shift + Alt + Control
365 12 Meta + Alt + Shift
367 14 Meta + Ctrl + Shift
369 16 Meta + Ctrl + Alt + Shift
371 None of these are predefined; terminal descriptions can refer to <EM>names</EM>
372 which <EM>ncurses</EM> will allocate at runtime to <EM>key-codes</EM>. To use these keys
373 in an <EM>ncurses</EM> program, an application could do this:
375 <STRONG>o</STRONG> using a list of extended key <EM>names</EM>, ask <STRONG><A HREF="curs_terminfo.3x.html">tigetstr(3x)</A></STRONG> for their
378 <STRONG>o</STRONG> given the list of values, ask <STRONG><A HREF="key_defined.3x.html">key_defined(3x)</A></STRONG> for the <EM>key-code</EM>
379 which would be returned for those keys by <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>.
382 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
383 The "-x" extension feature of <STRONG>tic</STRONG> and <STRONG>infocmp</STRONG> has been adopted in
384 NetBSD curses. That implementation stores user-defined capabilities,
385 but makes no use of these capabilities itself.
388 </PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
390 beginning with <EM>ncurses</EM> 5.0 (1999)
393 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
394 <STRONG><A HREF="infocmp.1m.html">infocmp(1m)</A></STRONG>, <STRONG><A HREF="tic.1m.html">tic(1m)</A></STRONG>
396 The terminal database section <EM>NCURSES</EM> <EM>USER-DEFINABLE</EM> <EM>CAPABILITIES</EM>
397 summarizes commonly-used user-defined capabilities which are used in
398 the terminal descriptions. Some of those features are mentioned in
399 <STRONG>screen(1)</STRONG> or <STRONG>tmux(1)</STRONG>.
401 <EM>XTerm</EM> <EM>Control</EM> <EM>Sequences</EM> provides further information on the <STRONG>xterm(1)</STRONG>
402 features that are used in these extended capabilities.
406 ncurses 6.5 2024-06-08 <STRONG><A HREF="user_caps.5.html">user_caps(5)</A></STRONG>
410 <li><a href="#h2-NAME">NAME</a></li>
411 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
412 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
414 <li><a href="#h3-Background">Background</a></li>
415 <li><a href="#h3-Recognized-Capabilities">Recognized Capabilities</a></li>
416 <li><a href="#h3-Extended-Key-Definitions">Extended Key Definitions</a></li>
419 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
420 <li><a href="#h2-AUTHORS">AUTHORS</a></li>
421 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>