NAME

       get_wch, wget_wch, mvget_wch, mvwget_wch, unget_wch - get (or push back) a wide character from curses
       terminal keyboard

SYNOPSIS

       #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);

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  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 assigned to the function key, and returning KEY_CODE_YES.  If a  charac‐
       ter  (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  charac‐
       ter;  otherwise, curses returns the function key value.  For this reason, many terminals experience a de‐
       lay 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:

       •   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_.

       •   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  or‐
       dinary  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  func‐
       tion  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  po‐
       sition is outside the window, or if the window pointer is null.

SEE ALSO

       ncurses(3NCURSES),  getch(3NCURSES), ins_wch(3NCURSES), inopts(3NCURSES), move(3NCURSES), refresh(3NCURS‐
       ES)

                                                                                               get_wch(3NCURSES)