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30 .\" $Id: curs_get_wch.3x,v 1.41 2024/05/11 20:39:53 tom Exp $
31 .TH curs_get_wch 3X 2024-05-11 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls"
53 get (or push back) a wide character from \fIcurses\fR terminal keyboard
56 \fB#include <curses.h>
58 \fBint get_wch(wint_t *\fIwch\fP);
59 \fBint wget_wch(WINDOW *\fIwin\fP, wint_t *\fIwch\fP);
60 \fBint mvget_wch(int \fIy\fP, int \fIx\fP, wint_t *\fIwch\fP);
61 \fBint mvwget_wch(WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, wint_t *\fIwch\fP);
63 \fBint unget_wch(const wchar_t \fIwc\fP);
66 .SS "Reading Characters"
68 gathers a key event from the terminal keyboard associated with a
74 if a wide character is read,
76 if a function key is read,
79 if no key event is available.
80 \fB\%ncurses\fP(3X) describes the variants of this function.
82 When input is pending,
85 identifying the key event in
87 for alphanumeric and punctuation keys,
88 this value corresponds to the character encoding used by the terminal.
89 Use of the control key as a modifier,
90 by holding it down while pressing and releasing another key,
91 often results in a distinct code.
92 The behavior of other keys depends on whether
95 see subsections \*(``Keypad Mode\*('' and \*(``Predefined Key Codes\*(''
98 If no input is pending,
99 then if the no-delay flag is set in the window
100 (see \fB\%nodelay\fP(3X)),
105 waits until the terminal has input.
106 If \fB\%cbreak\fP(3X)
108 this happens after one character is read.
109 If \fB\%nocbreak\fP(3X)
111 it occurs when the next newline is read.
112 If \fB\%halfdelay\fP(3X)
115 waits until input is available or the specified delay elapses.
117 If \fB\%echo\fP(3X) has been called,
118 and the window is not a pad,
123 (at the cursor position)
124 per the following rules.
128 matches the terminal's erase character,
129 the cursor moves leftward one position
130 and the new position is erased
131 as if \fB\%wmove\fP(3X) and then \fB\%wdelch\fP(3X) were called.
132 When the window's keypad mode is enabled
137 are handled the same way.
143 as with \fB\%wecho_wchar\fP(3X).
147 has been moved or modified since the last call to
148 \fB\%wrefresh\fP(3X),
156 is a carriage return and \fBnl\fP(3X) has been called,
158 stores the the character code for line feed in
161 .SS "Ungetting Characters"
165 into the input queue to be returned by the next call to
167 A single input queue serves all windows associated with the terminal.
172 when it reads a wide character and
174 when it reads a function key code.
185 its timeout expires without any data arriving,
188 execution was interrupted by a signal,
194 Functions prefixed with \*(``mv\*('' first perform cursor movement and
198 is outside the window boundaries.
205 if there is no more room in the input queue.
207 See the \*(``NOTES\*('' section of \fB\%wgetch\fP(3X).
209 All of these functions except
213 may be implemented as macros.
215 Unlike \fB\%wgetch\fP(3X),
217 and its variants store the value of the input character in an additional
219 parameter instead of the return value.
224 cannot distinguish function key codes from conventional character codes.
225 An application can overcome this limitation by pushing function key
228 and subsequently checking the return value of
231 .BR \%KEY_CODE_YES "."
233 See the \*(``EXTENSIONS\*('' section of \fB\%wgetch\fP(3X).
235 Applications employing
237 extensions should condition their use on the visibility of the
242 Issue 4 describes these functions.
243 It specifies no error conditions for them.
245 See the \*(``PORTABILITY\*('' section of \fB\%wgetch\fP(3X) regarding
248 with signal handlers.
250 \fB\%curs_getch\fP(3X) describes comparable functions of the
252 library in its non-wide-character configuration.
255 \fB\%curs_add_wch\fP(3X),
256 \fB\%curs_inopts\fP(3X),
257 \fB\%curs_move\fP(3X),
258 \fB\%curs_refresh\fP(3X)