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)