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curs_get_wch(3)                                                curs_get_wch(3)




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:

       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(3)

ncurses 6.4 - Generated Thu Jan 5 08:12:31 CST 2023
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