svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
has_key(3x)
curs_getch(3x) Library calls curs_getch(3x)
NAME
getch, wgetch, mvgetch, mvwgetch, ungetch, has_key - get (or push back)
characters from curses terminal keyboard buffer
SYNOPSIS
#include <ncursesw/curses.h>
int getch(void);
int wgetch(WINDOW * win);
int mvgetch(int y, int x);
int mvwgetch(WINDOW * win, int y, int x);
int ungetch(int c);
/* extension */
int has_key(int c);
DESCRIPTION
Reading Characters
wgetch gathers a key event from the terminal keyboard associated with a
curses window win. ncurses(3X) describes the variants of this func‐
tion.
When input is pending, wgetch returns an integer identifying the key
event; for alphanumeric and punctuation keys, this value corresponds to
the character encoding used by the terminal. Use of the control key as
a modifier, by holding it down while pressing and releasing another
key, often results in a distinct code. The behavior of other keys de‐
pends on whether win is in keypad mode; see subsection “Keypad Mode”
below.
If no input is pending, then if the no-delay flag is set in the window
(see nodelay(3X)), the function returns ERR; otherwise, curses waits
until the terminal has input. If cbreak(3X) or raw(3X) has been
called, this happens after one character is read. If nocbreak(3X) or
noraw(3X) has been called, it occurs when the next newline is read.
(Because the terminal's canonical or “cooked” mode is line-buffered,
multiple wgetch calls may then be necessary to empty the input queue.)
If halfdelay(3X) has been called, curses waits until input is available
or the specified delay elapses.
If echo(3X) has been called, and the window is not a pad, curses writes
the returned character c to the window (at the cursor position) per the
following rules.
• If c matches the terminal's erase character (see erasechar(3X)),
the cursor moves leftward one position and the new position is
erased as if wmove(3X) and then wdelch(3X) were called. When the
window's keypad mode is enabled (see below), KEY_LEFT and
KEY_BACKSPACE are handled the same way.
• curses writes any other c to the window, as with wechochar(3X).
• If the window win has been moved or modified since the last call to
wrefresh(3X), curses calls wrefresh on it.
If c is a carriage return and nl(3X) has been called, wgetch returns
the character code for line feed instead.
Keypad Mode
Call keypad(3X) on a window to configure keypad mode when reading input
from it. In keypad mode, curses treats key strokes not from the alpha‐
betic section of the keyboard (those corresponding to the ECMA-6 char‐
acter set — see ascii(7) — optionally modified by either the control or
shift keys) as function keys. (In curses, the term “function key” in‐
cludes but is not limited to keycaps engraved with “F1”, “PF1”, and so
on.) If a window is in keypad mode, wgetch translates these key
strokes to a numeric code corresponding to the KEY_ symbols listed in
subsection “Predefined Key Codes” below. If a window is not in keypad
mode, wgetch returns a sequence of codes typically starting with the
escape character, which the application must collect individually with
multiple wgetch calls.
• The curses.h header file declares many predefined function keys
whose names begin with KEY_; these object-like macros have integer
values outside the range of eight-bit character codes.
• In ncurses, user-defined function keys are configured with
define_key(3X); they have no names, but are also expected to have
integer values outside the range of eight-bit character codes.
A variable intended to hold a function key code must thus be of type
short or larger.
Most terminals one encounters follow the ECMA-48 standard insofar as
their function keys produce character sequences prefixed with the es‐
cape character ESC. This fact implies that curses cannot distinguish a
user's press of the escape key (assuming it sends ESC) from the begin‐
ning of a function key's character sequence without waiting to see if,
and how soon, further input arrives.
• If the escape sequence matches a string capability defining a func‐
tion key for the terminal type (such as key_home (khome) or key_up
(kuu1)), wgetch returns the function key code corresponding to the
unique sequence defined by the terminal.
• If the escape sequence matches no function keys defined for the
terminal type, call wgetch repeatedly to obtain the codes of the
individual characters of the sequence, in the order they occurred
in the input.
• If wgetch cannot decide the validity of the input as a function key
because it has not read enough characters to disambiguate it, the
function waits until it has this information or the escape delay
elapses. Configure the escape delay with the global variable
ESCDELAY, an extension (see section “EXTENSIONS” below), or the en‐
vironment variable of the same name (see section “ENVIRONMENT” of
ncurses(3X)), also an extension.
Consequently, a user of a curses application that employs keypad mode
may experience a pause or “hang” after pressing the escape key while
curses collects sufficient characters to disambiguate the input. If
the window is in “no time-out” mode, the escape delay is effectively
infinite; see notimeout(3X). In the event of such a pause, further
typing “awakens” curses.
Ungetting Characters
ungetch places c into the input queue to be returned by the next call
to wgetch. A single input queue serves all windows associated with the
screen.
Predefined Key Codes
The header file curses.h defines the following function key codes.
• Except for the special case of KEY_RESIZE, a window's keypad mode
must be enabled for wgetch to read these codes from it.
• Not all of these are necessarily supported on any particular termi‐
nal.
• The naming convention may seem obscure, with some apparent mis‐
spellings (such as “RSUME” for “resume”); the names correspond to
the terminfo capability names for the keys, and were standardized
before the IBM PC/AT keyboard layout achieved a dominant position
in industry.
Lb Lb Lb Lx. Symbol Key name = KEY_BREAK Break key
KEY_DOWN Arrow keys KEY_UP KEY_LEFT KEY_RIGHT
KEY_HOME Home key (upward+left arrow) KEY_BACKSPACE Backspace
KEY_F0 T{ Function keys; space for 64 keys is reserved T}
KEY_F(n) T{ Function key n where 0 ≤ n ≤ 63 T} KEY_DL Delete
line KEY_IL Insert line KEY_DC Delete character
KEY_IC Insert character/Enter insert mode KEY_EIC Exit in‐
sert character mode KEY_CLEAR Clear screen KEY_EOS Clear to
end of screen KEY_EOL Clear to end of line KEY_SF Scroll
one line forward KEY_SR Scroll one line backward (reverse)
KEY_NPAGE Next page/Page up KEY_PPAGE Previous page/Page down
KEY_STAB Set tab KEY_CTAB Clear tab KEY_CATAB Clear all tabs
KEY_ENTER Enter/Send KEY_SRESET Soft (partial) reset KEY_RE‐
SET (Hard) reset KEY_PRINT Print/Copy KEY_LL Home down/Bottom
(lower left) KEY_A1 Upper left of keypad KEY_A3 Upper
right of keypad KEY_B2 Center of keypad KEY_C1 Lower left
of keypad KEY_C3 Lower right of keypad KEY_BTAB Back tab key
KEY_BEG Beg(inning) key KEY_CANCEL Cancel key
KEY_CLOSE Close key KEY_COMMAND Cmd (command) key
KEY_COPY Copy key KEY_CREATE Create key KEY_END End key
KEY_EXIT Exit key KEY_FIND Find key KEY_HELP Help key
KEY_MARK Mark key KEY_MESSAGE Message key KEY_MOUSE Mouse
event occurred KEY_MOVE Move key KEY_NEXT Next object key
KEY_OPEN Open key KEY_OPTIONS Options key KEY_PREVI‐
OUS Previous object key KEY_REDO Redo key KEY_REFER‐
ENCE Ref(erence) key KEY_REFRESH Refresh key KEY_RE‐
PLACE Replace key KEY_RESIZE Screen resized
KEY_RESTART Restart key KEY_RESUME Resume key
KEY_SAVE Save key KEY_SELECT Select key KEY_SUSPEND Sus‐
pend key KEY_UNDO Undo key _ KEY_SBEG Shifted beginning key
KEY_SCANCEL Shifted cancel key KEY_SCOMMAND Shifted command
key KEY_SCOPY Shifted copy key KEY_SCREATE Shifted create key
KEY_SDC Shifted delete character key KEY_SDL Shifted delete
line key KEY_SEND Shifted end key KEY_SEOL Shifted clear line
key KEY_SEXIT Shifted exit key KEY_SFIND Shifted find key
KEY_SHELP Shifted help key KEY_SHOME Shifted home key
KEY_SIC Shifted insert key KEY_SLEFT Shifted left arrow key
KEY_SMESSAGE Shifted message key KEY_SMOVE Shifted move key
KEY_SNEXT Shifted next object key KEY_SOPTIONS Shifted options
key KEY_SPREVIOUS Shifted previous object key
KEY_SPRINT Shifted print key KEY_SREDO Shifted redo key
KEY_SREPLACE Shifted replace key KEY_SRIGHT Shifted right
arrow key KEY_SRSUME Shifted resume key KEY_SSAVE Shifted
save key KEY_SSUSPEND Shifted suspend key KEY_SUNDO Shifted
undo key
Many keyboards feature a nine-key directional pad.
allbox center; C C C. A1 up A3 left B2 right C1 down C3
Two of the symbols in the list above do not correspond to a physical
key.
• wgetch returns KEY_RESIZE, even if the window's keypad mode is dis‐
abled, if ncurses has handled a SIGWINCH signal since wgetch was
called; see initscr(3X) and resizeterm(3X).
• wgetch returns KEY_MOUSE to indicate that a mouse event is pending
collection; see curs_mouse(3X). Receipt of this code requires a
window's keypad mode to be enabled, because to interpret mouse in‐
put (as with xterm(1)'s mouse protocol), ncurses must read an es‐
cape sequence, as with a function key.
Testing Key Codes
In ncurses, has_key returns a Boolean value indicating whether the ter‐
minal type recognizes its parameter as a key code value. See also
define_key(3X) and key_defined(3X).
RETURN VALUE
wgetch returns a key code identifying the key event as described above,
which may include KEY_RESIZE or KEY_MOUSE indicating non-key events, or
ERR on failure. wgetch fails if its timeout expires without any data
arriving, which cannot happen if nodelay(3X) is in effect on the win‐
dow.
In ncurses, wgetch also fails if
• the curses screen has not been initialized,
• (for functions taking a WINDOW pointer argument) win is a null
pointer, or
• execution was interrupted by a signal, in which case errno is set
to EINTR.
Functions prefixed with “mv” first perform cursor movement and fail if
the position (y, x) is outside the window boundaries.
ungetch returns OK on success and ERR on failure. In ncurses, ungetch
fails if
• the curses screen has not been initialized, or
• there is no more room in the input queue.
has_key returns TRUE or FALSE.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
box; cbp-1 | cbp-1 l | l . ATTRIBUTE TYPE ATTRIBUTE VALUE = Availabil‐
ity library/ncurses = Stability Uncommitted
NOTES
getch, mvgetch, and mvwgetch may be implemented as macros.
curses discourages assignment of the ESC key to a discrete function by
the programmer because the library requires a delay while it awaits the
potential remainder of a terminal escape sequence.
Some key strokes are indistinguishable from control characters; for ex‐
ample, KEY_ENTER may be the same as ^M, and KEY_BACKSPACE may be the
same as ^H or ^?. Consult the terminfo entry for the terminal type to
determine whether this is the case; see infocmp(1). Some curses imple‐
mentations, including ncurses, honor the terminfo key definitions; oth‐
ers treat such control characters specially.
curses distinguishes the Enter keys in the alphabetic and numeric key‐
pad sections of a keyboard because (most) terminals do. KEY_ENTER
refers to the key on the numeric keypad and, like other function keys,
is reliably recognized only if the window's keypad mode is enabled.
• The terminfo key_enter (kent) capability describes the character
(sequence) sent by the Enter key of a terminal's numeric (or simi‐
lar) keypad.
• “Enter or send” is X/Open Curses's description of this key.
curses treats the Enter or Return key in the alphabetic section of the
keyboard differently.
• It usually produces a control code for carriage return (^M) or line
feed (^J).
• Depending on the terminal mode (raw, cbreak, or canonical), and
whether nl(3X) or nonl(3X) has been called, wgetch may return ei‐
ther a carriage return or line feed upon an Enter or Return key
stroke.
Use of wgetch with echo(3X) and neither cbreak(3X) nor raw(3X) is not
well-defined.
Historically, the list of key code macros above was influenced by the
keyboard of the AT&T 7300 (also known variously as the “3B1”, “Safari
4”, and “UNIX PC”), a 1985 machine rich in function keys. Today's com‐
puter keyboards are based on that of the IBM PC/AT and tend to have
fewer. A curses application can expect such a keyboard to transmit key
codes KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT, KEY_HOME, KEY_END,
KEY_PPAGE (Page Up), KEY_NPAGE (Page Down), KEY_IC (Insert), KEY_DC
(Delete), KEY_A1, KEY_A3, KEY_B2, KEY_C1, KEY_C3, and KEY_F(n) for 1 ≤
n ≤ 12.
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at:
https://github.com/oracle/solaris-userland
The original community source was downloaded from:
https://invisible-mirror.net/archives/ncurses/cur‐
rent/ncurses-6.5-20250614.tgz
Further information about this software can be found on the open source
community website at https://invisible-island.net/ncurses/.
EXTENSIONS
In ncurses, when a window's “no time-out” mode is not set, the ESCDELAY
variable configures the duration of the timer used to disambiguate a
function key character sequence from a series of key strokes beginning
with ESC typed by the user; see curs_variables(3X).
has_key is an ncurses extension, and is not found in SVr4 curses,
4.4BSD curses, or any other previous curses implementation.
PORTABILITY
Applications employing ncurses extensions should condition their use on
the visibility of the NCURSES_VERSION preprocessor macro.
Except as noted in section “EXTENSIONS” above, X/Open Curses Issue 4
describes these functions. It specifies no error conditions for them.
SVr4 describes a successful return value only as “an integer value
other than ERR”.
wgetch reads only single-byte characters.
The echo behavior of these functions on input of KEY_ or backspace
characters is not documented in SVr4 curses.
The behavior of wgetch in the presence of signal handlers is not docu‐
mented in SVr4 curses and is unspecified by X/Open Curses. In histori‐
cal curses implementations, it varied depending on whether the operat‐
ing system's dispatch of a signal to a handler interrupted a read(2)
call in progress, and also (in some implementations) whether an input
timeout or non-blocking mode had been set. A portable curses applica‐
tion prepares for two cases: (a) signal receipt does not interrupt
wgetch; or (b) signal receipt interrupts wgetch and causes it to return
ERR with errno set to EINTR.
KEY_MOUSE is mentioned in X/Open Curses, along with a few related term‐
info capabilities, but no higher-level functions use the feature. The
implementation in ncurses is an extension.
KEY_RESIZE and has_key are extensions first implemented for ncurses.
By 2022, PDCurses and NetBSD curses had added them along with
KEY_MOUSE.
HISTORY
4BSD (1980) introduced wgetch and its variants.
SVr3 (1987) added ungetch.
ncurses 1.9.9g (1996) furnished the has_key extension.
SEE ALSO
ECMA-6 “7-bit coded Character Set” <https://ecma-international.org/
publications-and-standards/standards/ecma-6/>
ECMA-48 “Control Functions for Coded Character Sets” <https://
ecma-international.org/publications-and-standards/standards/ecma-48/>
curs_get_wch(3X) describes comparable functions of the ncurses library
in its wide-character configuration (ncursesw).
curses(3X), curs_addch(3X), curs_inopts(3X), curs_mouse(3X),
curs_move(3X), curs_outopts(3X), curs_refresh(3X), curs_variables(3X),
resizeterm(3X), ascii(7)
ncurses 6.5 2025-04-05 curs_getch(3x)