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
       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:

       •   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(3NCURSES) 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.

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.

NOTES

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

PORTABILITY

       These functions are described in the XSI Curses standard, Issue 4.

SEE ALSO

       ncurses(3NCURSES),      getch(3NCURSES),     inopts(3NCURSES),     ins_wch(3NCURSES),     move(3NCURSES),
       refresh(3NCURSES)