- Before ncurses 5.0, terminfo databases used a fixedrepertoire of
+ Before ncurses 5.0, terminfo databases used a fixedrepertoire of
terminal capabilities designed for the SVr2 terminal database in 1984,
and extended in stages through SVr4 (1989), and standardized in the
Single Unix Specification beginning in 1995.
- Most of the extensions in this fixed repertoire were additions to the
- tables of boolean, numeric and string capabilities. Rather than change
+ Most of the extensions in this fixed repertoire were additions to the
+ tables of Boolean, numeric and string capabilities. Rather than change
the meaning of an existing capability, a new name was added. The
terminfo database uses a binary format; binary compatibility was
ensured by using a header which gave the number of items in the tables
for each type of capability. The standardization was incomplete:
- o The binaryformat itself is not described in the X/Open Curses
- documentation. Only the sourceformat is described.
+ o The binaryformat itself is not described in the X/Open Curses
+ documentation. Only the sourceformat is described.
Library developers rely upon the SVr4 documentation, and reverse-
engineering the compiled terminfo files to match the binary format.
- o Lacking a standard for the binary format, most implementations copy
+ o Lacking a standard for the binary format, most implementations copy
the SVr2 binary format, which uses 16-bit signed integers, and is
limited to 4096-byte entries.
The format cannot represent very large numeric capabilities, nor
can it represent large numbers of special keyboard definitions.
- o The tables of capability names differ between implementations.
+ o The tables of capability names differ between implementations.
- Although they may provide all of the standard capability names, the
+ Although they may provide all of the standard capability names, the
position in the tables differs because some features were added as
needed, while others were added (out of order) to comply with
X/Open Curses.
- While ncurses' repertoire of predefined capabilities is closest to
+ While ncurses' repertoire of predefined capabilities is closest to
Solaris, Solaris's terminfo database has a few differences from the
- list published by X/Open Curses. For example, ncurses can be
+ list published by X/Open Curses. For example, ncurses can be
configured with tables which match the terminal databases for AIX,
HP-UX or OSF/1, rather than the default Solaris-like configuration.
- o In SVr4 curses and ncurses, the terminal database is defined at
+ o In SVr4 curses and ncurses, the terminal database is defined at
compile-time using a text file which lists the different terminal
capabilities.
In principle, the text-file can be extended, but doing this
requires recompiling and reinstalling the library. The text-file
- used in ncurses for terminal capabilities includes details for
+ used in ncurses for terminal capabilities includes details for
various systems past the documented X/Open Curses features. For
- example, ncurses supports these capabilities in each configuration:
+ example, ncurses supports these capabilities in each configuration:
memory_lock
(meml) lock memory above cursor
@@ -115,60 +118,60 @@
(box1) box characters primary set
The memory lock/unlock capabilities were included because they were
- used in the X11R6 terminal description for xterm. The box1
+ used in the X11R6 terminal description for xterm(1). The box1
capability is used in tic to help with terminal descriptions
written for AIX.
During the 1990s, some users were reluctant to use terminfo in spite of
its performance advantages over termcap:
- o The fixed repertoire prevented users from adding features for
+ o The fixed repertoire prevented users from adding features for
unanticipated terminal improvements (or required them to reuse
existing capabilities as a workaround).
- o The limitation to 16-bit signed integers was also mentioned.
+ o The limitation to 16-bit signed integers was also mentioned.
Because termcap stores everything as a string, it could represent
larger numbers.
Although termcap's extensibility was rarely used (it was never the
- speaker who had actually used the feature), the criticism had a point.
- ncurses 5.0 provided a way to detect nonstandard capabilities,
+ speaker who had actually used the feature), the criticism had a point.
+ ncurses 5.0 provided a way to detect nonstandard capabilities,
determine their type and optionally store and retrieve them in a way
which did not interfere with other applications. These are referred to
- as user-definedcapabilities because no modifications to the toolset's
+ as user-definedcapabilities because no modifications to the toolset's
predefined capability names are needed.
- The ncurses utilities tic and infocmp have a command-line option "-x"
+ The ncurses utilities tic and infocmp have a command-line option "-x"
to control whether the nonstandard capabilities are stored or
- retrieved. A library function use_extended_names is provided for the
+ retrieved. A library function use_extended_names is provided for the
same purpose.
- When compiling a terminal database, if "-x" is set, tic will store a
+ When compiling a terminal database, if "-x" is set, tic will store a
user-defined capability if the capability name is not one of the
predefined names.
- Because ncurses provides a termcap library interface, these user-
+ Because ncurses provides a termcap library interface, these user-
defined capabilities may be visible to termcap applications:
- o The termcap interface (like all implementations of termcap)
+ o The termcap interface (like all implementations of termcap)
requires that the capability names are 2-characters.
When the capability is simple enough for use in a termcap
application, it is provided as a 2-character name.
- o There are other user-defined capabilities which refer to features
+ o There are other user-defined capabilities which refer to features
not usable in termcap, e.g., parameterized strings that use more
than two parameters or use more than the trivial expression support
provided by termcap. For these, the terminfo database should have
only capability names with 3 or more characters.
- o Some terminals can send distinct strings for special keys (cursor-,
+ o Some terminals can send distinct strings for special keys (cursor-,
keypad- or function-keys) depending on modifier keys (shift,
control, etc.). While terminfo and termcap have a set of 60
predefined function-key names, to which a series of keys can be
assigned, that is insufficient for more than a dozen keys
multiplied by more than a couple of modifier combinations. The
- ncurses database uses a convention based on xterm to provide
+ ncurses database uses a convention based on xterm(1) to provide
extended special-key names.
Fitting that into termcap's limitation of 2-character names would
@@ -176,35 +179,41 @@
terminfo.
-
+ The ncurses library uses the user-definable capabilities. While the
+ terminfo database may have other extensions, ncurses makes explicit
checks for these:
- AX boolean, asserts that the terminal interprets SGR 39 and SGR 49
+ AX Boolean, asserts that the terminal interprets SGR 39 and SGR 49
by resetting the foreground and background color, respectively,
to the default.
- This is a feature recognized by the screen program as well.
+ This is a feature recognized by the screen program as well.
- E3 string, tells how to clear the terminal's scrollback buffer.
- When present, the clear(1) program sends this before clearing the
+ E3 string, tells how to clear the terminal's scrollback buffer.
+ When present, the clear(1) program sends this before clearing the
terminal.
- The command "tputclear" does the same thing.
+ The command "tputclear" does the same thing.
+
+ NQ Boolean, used to suppress a consistency check in tic for the
+ ncurses capabilities in user6 through user9 (u6, u7, u8 and u9)
+ which tell how to query the terminal's cursor position and its
+ device attributes.
RGB
- boolean, numberorstring, to assert that the set_a_foreground
- and set_a_background capabilities correspond to directcolors,
- using an RGB (red/green/blue) convention. This capability allows
- the color_content function to return appropriate values without
- requiring the application to initialize colors using init_color.
+ Boolean, numberorstring, used to assert that the
+ set_a_foreground and set_a_background capabilities correspond to
+ directcolors, using an RGB (red/green/blue) convention. This
+ capability allows the color_content function to return
+ appropriate values without requiring the application to
+ initialize colors using init_color.
- The capability type determines the values which ncurses sees:
+ The capability type determines the values which ncurses sees:
- boolean
+ Boolean
implies that the number of bits for red, green and blue are
- the same. Using the maximum number of colors, ncurses adds
+ the same. Using the maximum number of colors, ncurses adds
two, divides that sum by three, and assigns the result to red,
green and blue in that order.
@@ -212,50 +221,50 @@
multiple of three, the blue (and green) components lose in
comparison to red.
- number
- tells ncurses what result to add to red, green and blue. If
- ncurses runs out of bits, blue (and green) lose just as in the
- boolean case.
+ number
+ tells ncurses what result to add to red, green and blue. If
+ ncurses runs out of bits, blue (and green) lose just as in the
+ Boolean case.
- string
+ string
explicitly list the number of bits used for red, green and
blue components as a slash-separated list of decimal integers.
Because there are several RGB encodings in use, applications
which make assumptions about the number of bits per color are
unlikely to work reliably. As a trivial case, for example, one
- could define RGB#1 to represent the standard eight ANSI colors,
+ could define RGB#1 to represent the standard eight ANSI colors,
i.e., one bit per color.
- U8 number, asserts that ncurses must use Unicode values for line-
+ U8 number, asserts that ncurses must use Unicode values for line-
drawing characters, and that it should ignore the alternate
character set capabilities when the locale uses UTF-8 encoding.
- For more information, see the discussion of NCURSES_NO_UTF8_ACS
- in ncurses(3X).
+ For more information, see the discussion of NCURSES_NO_UTF8_ACS
+ in ncurses(3x).
Set this capability to a nonzero value to enable it.
- XM string, override ncurses's built-in string which enables/disables
- xterm mouse mode.
+ XM string, override ncurses's built-in string which enables/disables
+ xterm(1) mouse mode.
- ncurses sends a character sequence to the terminal to initialize
+ ncurses sends a character sequence to the terminal to initialize
mouse mode, and when the user clicks the mouse buttons or (in
certain modes) moves the mouse, handles the characters sent back
by the terminal to tell it what was done with the mouse.
- The mouse protocol is enabled when the mask passed in the
- mousemask function is nonzero. By default, ncurses handles the
+ The mouse protocol is enabled when the mask passed in the
+ mousemask function is nonzero. By default, ncurses handles the
responses for the X11 xterm mouse protocol. It also knows about
- the SGR1006 xterm mouse protocol, but must to be told to look
+ the SGR1006 xterm mouse protocol, but must to be told to look
for this specifically. It will not be able to guess which mode
is used, because the responses are enough alike that only
confusion would result.
- The XM capability has a single parameter. If nonzero, the mouse
+ The XM capability has a single parameter. If nonzero, the mouse
protocol should be enabled. If zero, the mouse protocol should
- be disabled. ncurses inspects this capability if it is present,
+ be disabled. ncurses inspects this capability if it is present,
to see whether the 1006 protocol is used. If so, it expects the
- responses to use the SGR1006 xterm mouse protocol.
+ responses to use the SGR1006 xterm mouse protocol.
The xterm mouse protocol is used by other terminal emulators.
The terminal database uses building-blocks for the various xterm
@@ -263,29 +272,29 @@
descriptions.
The terminal database building blocks for this mouse feature also
- have an experimental capability xm. The "xm" capability
+ have an experimental capability xm. The "xm" capability
describes the mouse response. Currently there is no interpreter
which would use this information to make the mouse support
completely data-driven.
- xm shows the format of the mouse responses. In this experimental
+ xm shows the format of the mouse responses. In this experimental
capability, the parameters are
- p1 y-ordinate
+ p1 y-ordinate
- p2 x-ordinate
+ p2 x-ordinate
- p3 button
+ p3 button
- p4 state, e.g., pressed or released
+ p4 state, e.g., pressed or released
- p5 y-ordinate starting region
+ p5 y-ordinate starting region
- p6 x-ordinate starting region
+ p6 x-ordinate starting region
- p7 y-ordinate ending region
+ p7 y-ordinate ending region
- p8 x-ordinate ending region
+ p8 x-ordinate ending region
Here are examples from the terminal database for the most
commonly used xterm mouse protocols:
@@ -305,36 +314,43 @@
%?%p4%tM%em%;,
-
Several terminals provide the ability to send distinct strings for
combinations of modified special keys. There is no standard for what
those keys can send.
- Since 1999, xterm has supported shift, control, alt, and meta modifiers
- which produce distinct special-key strings. In a terminal description,
- ncurses has no special knowledge of the modifiers used. Applications
- can use the namingconvention established for xterm to find these
- special keys in the terminal description.
-
- Starting with the curses convention that keynames begin with "k" and
- that shifted special keys are an uppercase name, ncurses' terminal
- database defines these names to which a suffix is added:
-
- NameDescription
- ---------------------------------------------------------------
- kDC special form of kdch1 (delete character)
- kDN special form of kcud1 (cursor down)
- kEND special form of kend (End)
- kHOM special form of khome (Home)
- kLFT special form of kcub1 (cursor-left or cursor-back)
- kNXT special form of knext (Next, or Page-Down)
- kPRV special form of kprev (Prev, or Page-Up)
- kRIT special form of kcuf1 (cursor-right, or cursor-forward)
- kUP special form of kcuu1 (cursor-up)
+ Since 1999, xterm(1) has supported shift, control, alt, and meta
+ modifiers which produce distinct special-key strings. In a terminal
+ description, ncurses has no special knowledge of the modifiers used.
+ Applications can use the namingconvention established for xterm to
+ find these special keys in the terminal description.
+
+ Starting with the curses convention that capability codes describing
+ the input generated by a terminal's key caps begin with "k", and that
+ shifted special keys use uppercase letters in their names, ncurses's
+ terminal database defines the following names and codes to which a
+ suffix is added.
+
+ CodeDescription
+ -------------------------------------------------------------------
+ kDC shifted kdch1 (delete character)
+ kDN shifted kcud1 (cursor down)
+ kEND shifted kend (end)
+ kHOM shifted khome (home)
+ kLFT shifted kcub1 (cursor back)
+ kNXT shifted knext (next)
+ kPRV shifted kprev (previous)
+ kRIT shifted kcuf1 (cursor forward)
+ kUP shifted kcuu1 (cursor up)
+
+ Keycap nomenclature on the Unix systems for which curses was developed
+ differs from today's ubiquitous descendants of the IBM PC/AT keyboard
+ layout. In the foregoing, interpret "backward" as "left", "forward" as
+ "right", "next" as "page down", and "prev(ious)" as "page up".
These are the suffixes used to denote the modifiers:
- ValueDescription
+ ValueDescription
----------------------------------
2 Shift
3 Alt
@@ -352,42 +368,42 @@
15 Meta + Ctrl + Alt
16 Meta + Ctrl + Alt + Shift
- None of these are predefined; terminal descriptions can refer to names
- which ncurses will allocate at runtime to key-codes. To use these keys
- in an ncurses program, an application could do this:
+ None of these are predefined; terminal descriptions can refer to names
+ which ncurses will allocate at runtime to key-codes. To use these keys
+ in an ncurses program, an application could do this:
- o using a list of extended key names, ask tigetstr(3X) for their
+ o using a list of extended key names, ask tigetstr(3x) for their
values, and
- o given the list of values, ask key_defined(3X) for the key-code
- which would be returned for those keys by wgetch(3X).
+ o given the list of values, ask key_defined(3x) for the key-code
+ which would be returned for those keys by wgetch(3x).
- The "-x" extension feature of tic and infocmp has been adopted in
- NetBSD curses. That implementation stores user-defined capabilities,
+ The "-x" extension feature of tic and infocmp has been adopted in
+ NetBSD curses. That implementation stores user-defined capabilities,
but makes no use of these capabilities itself.
-
+ Thomas E. Dickey
+ beginning with ncurses 5.0 (1999)
- The terminal database section NCURSESUSER-DEFINABLECAPABILITIES
- summarizes commonly-used user-defined capabilities which are used in
- the terminal descriptions. Some of those features are mentioned in
- screen(1) or tmux(1).
- XTermControlSequences provides further information on the xterm
- features which are used in these extended capabilities.
+
+ infocmp(1m), tic(1m)
+ The terminal database section NCURSESUSER-DEFINABLECAPABILITIES
+ summarizes commonly-used user-defined capabilities which are used in
+ the terminal descriptions. Some of those features are mentioned in
+ screen(1) or tmux(1).
-
- Thomas E. Dickey
- beginning with ncurses 5.0 (1999)
+ XTermControlSequences provides further information on the xterm(1)
+ features that are used in these extended capabilities.
- user_caps(5)
+ncurses 6.5 2024-03-16 user_caps(5)