DragonFly On-Line Manual Pages
curs_get_wch(3X) curs_get_wch(3X)
NAME
get_wch, wget_wch, mvget_wch, mvwget_wch, unget_wch - get (or push
back) a wide character from curses terminal keyboard
SYNOPSIS
#include <ncurses/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);
DESCRIPTION
wget_wch
The get_wch, wget_wch, mvget_wch, and mvwget_wch functions read a
character from the terminal associated with the current or specified
window. In no-delay mode, if no input is waiting, the value ERR is
returned. 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
assigned 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 received, curses sets a timer. If the remainder of the sequence
does arrive 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
begin with KEY_.
o Other (user-defined) function keys which may be defined using
define_key(3X) have no names, but also are expected to have values
outside the range of 8-bit characters.
unget_wch
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
program 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
characters 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.
NOTES
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
program may produce undesirable results.
All functions except wget_wch and unget_wch may be macros.
RETURN VALUE
When get_wch, wget_wch, mvget_wch, and mvwget_wch functions
successfully report the pressing of a function key, they return
KEY_CODE_YES. When they successfully report a wide character, they
return OK. Otherwise, they return ERR.
Upon successful completion, unget_wch returns OK. Otherwise, the
function 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.
SEE ALSO
curses(3X), curs_getch(3X), curs_ins_wch(3X), curs_inopts(3X),
curs_move(3X), curs_refresh(3X)
curs_get_wch(3X)