# curs_get_wch 3x 2024-04-20 ncurses 6.4 Library calls

    curs_get_wch(3x)                 Library calls                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 <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 wc);

## DESCRIPTION

### Reading Characters

           wget_wch gathers a key stroke wch from the terminal keyboard associated
           with  a  curses  window  win, returning OK if a wide character is read,
           KEY_CODE_YES if a function key is read, and ERR  if  no  key  event  is
           available.  ncurses(3x) describes the variants of this function.

           When  input  is pending, wget_wch stores an integer identifying the key
           stroke in wch;  for  alphanumeric  and  punctuation  keys,  this  value
           corresponds to the character encoding used by the terminal.  Use of the
           control key as a modifier  often  results  in  a  distinct  code.   The
           behavior  of  other  keys depends on whether win is in keypad mode; see
           subsections "Keypad Mode" and "Predefined Key Codes" in getch(3x).

           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)  has  been  called,  this
           happens  after one character is read.  If nocbreak(3x) has been called,
           it occurs when the next newline is read.   If  halfdelay(3x)  has  been
           called,  curses waits until a character is typed or the specified delay
           elapses.

           If echo(3x) has been called, and the window is not a pad, curses writes
           wch to the window (at the cursor position) per the following rules.

           o   If  wch  matches  the  terminal's erase character, 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.

           o   curses writes any other wch to the window, as with wecho_wchar(3x).

           o   If  the  window  has  been moved or modified since the last call to
               wrefresh(3x), curses calls wrefresh.

           If wch is a carriage return and nl(3x) has been called,  wgetch  stores
           the the character code for newline (line feed) in wch instead.

### Ungetting Characters

           unget_wch  places  wch  into the input queue to be returned by the next
           call to wget_wch.  A single input queue serves all windows.

## RETURN VALUE

           wget_wch returns OK when it reads a  wide  character  and  KEY_CODE_YES
           when it reads a function key code.  It returns ERR if

           o   the WINDOW pointer is NULL, or

           o   its timeout expires without any data arriving, or

           o   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.

           unget_wch returns OK on success and ERR if there is no more room in the
           input queue.

## NOTES

           See the "NOTES" section of wgetch(3x).

           All of these functions except wget_wch and unget_wch may be implemented
           as macros.

           Unlike  wgetch(3x),  wget_wch  and  its variants store the value of the
           input character in an additional wch parameter instead  of  the  return
           value.

           Unlike   ungetch,  unget_wch  cannot  distinguish  function  key  codes
           wget_wch  from  conventional  character  codes.   An  application   can
           overcome this limitation by pushing function key codes with ungetch and
           subsequently checking the return value of wget_wch  for  a  match  with
           KEY_CODE_YES.

## EXTENSIONS

           See the "EXTENSIONS" section of wgetch(3x).

## PORTABILITY

           Applications employing ncurses extensions should condition their use on
           the visibility of the NCURSES_VERSION preprocessor macro.

           X/Open Curses, Issue 4 describes  these  functions.   It  specifies  no
           error conditions for them.

           See  the  "PORTABILITY" section of wgetch(3x) regarding the interaction
           of wget_wch with signal handlers.

## SEE ALSO

           curs_getch(3x) describes comparable functions of the ncurses library in
           its non-wide-character configuration.

           curses(3x),     curs_add_wch(3x),    curs_inopts(3x),    curs_move(3x),
           curs_refresh(3x)

    ncurses 6.4                       2024-04-20                  curs_get_wch(3x)