curs_get_wch(3x) curs_get_wch(3x)
get_wch, wget_wch, mvget_wch, mvwget_wch, unget_wch - get (or push
back) a wide character from curses terminal keyboard
#include <curses.h>
int get_wch(wint_t *wch);
int wget_wch(WINDOW *win, wint_t *wch);
int mvget_wch(int y, int x, wint_t *wch);
int mvwget_wch(WINDOW *win, int y, int x, wint_t *wch);
int unget_wch(const wchar_t wch);
The get_wch, wget_wch, mvget_wch, and mvwget_wch functions read a char-
acter from the terminal associated with the current or specified win-
dow. In no-delay mode, if no input is waiting, the value ERR is re-
turned. In delay mode, the program waits until the system passes text
through to the program. Depending on the setting of cbreak, this is
after one character (cbreak mode), or after the first newline (nocbreak
mode). In half-delay mode, the program waits until the user types a
character or the specified timeout interval has elapsed.
Unless noecho has been set, these routines echo the character into the
designated window.
If the window is not a pad and has been moved or modified since the
last call to wrefresh, wrefresh will be called before another character
is read.
If keypad is enabled, these functions respond to the pressing of a
function key by setting the object pointed to by wch to the keycode as-
signed to the function key, and returning KEY_CODE_YES. If a character
(such as escape) that could be the beginning of a function key is re-
ceived, curses sets a timer. If the remainder of the sequence does ar-
rive within the designated time, curses passes through the character;
otherwise, curses returns the function key value. For this reason,
many terminals experience a delay between the time a user presses the
escape key and the time the escape is returned to the program.
The keycodes returned by these functions are the same as those returned
by wgetch:
o The predefined function keys are listed in <curses.h> as macros
with values outside the range of 8-bit characters. Their names be-
gin with KEY_.
o Other (user-defined) function keys which may be defined using de-
fine_key(3x) have no names, but also are expected to have values
outside the range of 8-bit characters.
The unget_wch function pushes the wide character wch back onto the head
of the input queue, so the wide character is returned by the next call
to get_wch. The pushback of one character is guaranteed. If the pro-
gram calls unget_wch too many times without an intervening call to
get_wch, the operation may fail.
Unlike ungetch and wgetch, unget_wch cannot distinguish special charac-
ters returned by wget_wch from ordinary characters. An application can
push special keys which it may read via wget_wch by checking for the
KEY_CODE_YES result, and using ungetch for those special keys.
The header file <curses.h> automatically includes the header file
<stdio.h>.
Applications should not define the escape key by itself as a single-
character function.
When using get_wch, wget_wch, mvget_wch, or mvwget_wch, applications
should not use nocbreak mode and echo mode at the same time. Depending
on the state of the tty driver when each character is typed, the pro-
gram may produce undesirable results.
All functions except wget_wch and unget_wch may be macros.
When get_wch, wget_wch, mvget_wch, and mvwget_wch functions successful-
ly report the pressing of a function key, they return KEY_CODE_YES.
When they successfully report a wide character, they return OK. Other-
wise, they return ERR.
Upon successful completion, unget_wch returns OK. Otherwise, the func-
tion returns ERR.
Functions with a "mv" prefix first perform a cursor movement using
wmove, and return an error if the position is outside the window, or if
the window pointer is null.
curses(3x), curs_getch(3x), curs_ins_wch(3x), curs_inopts(3x),
curs_move(3x), curs_refresh(3x)
curs_get_wch(3x)