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curs_inopts(3X)                                                curs_inopts(3X)

       cbreak, nocbreak, echo, noecho, halfdelay, intrflush, keypad, meta,
       nodelay, notimeout, raw, noraw, noqiflush, qiflush, timeout, wtimeout,
       typeahead - curses input options

       #include <curses.h>

       int cbreak(void);
       int nocbreak(void);
       int echo(void);
       int noecho(void);
       int halfdelay(int tenths);
       int intrflush(WINDOW *win, bool bf);
       int keypad(WINDOW *win, bool bf);
       int meta(WINDOW *win, bool bf);
       int nodelay(WINDOW *win, bool bf);
       int raw(void);
       int noraw(void);
       void noqiflush(void);
       void qiflush(void);
       int notimeout(WINDOW *win, bool bf);
       void timeout(int delay);
       void wtimeout(WINDOW *win, int delay);
       int typeahead(int fd);

       Normally, the tty driver buffers typed characters until a newline or
       carriage return is typed.  The cbreak routine disables line buffering
       and erase/kill character-processing (interrupt and flow control
       characters are unaffected), making characters typed by the user
       immediately available to the program.  The nocbreak routine returns the
       terminal to normal (cooked) mode.

       Initially the terminal may or may not be in cbreak mode, as the mode is
       inherited; therefore, a program should call cbreak or nocbreak
       explicitly.  Most interactive programs using curses set the cbreak
       mode.  Note that cbreak overrides raw.  [See curs_getch(3X) for a
       discussion of how these routines interact with echo and noecho.]

       The echo and noecho routines control whether characters typed by the
       user are echoed by getch as they are typed.  Echoing by the tty driver
       is always disabled, but initially getch is in echo mode, so characters
       typed are echoed.  Authors of most interactive programs prefer to do
       their own echoing in a controlled area of the screen, or not to echo at
       all, so they disable echoing by calling noecho.  [See curs_getch(3X)
       for a discussion of how these routines interact with cbreak and

       The halfdelay routine is used for half-delay mode, which is similar to
       cbreak mode in that characters typed by the user are immediately
       available to the program.  However, after blocking for tenths tenths of
       seconds, ERR is returned if nothing has been typed.  The value of
       tenths must be a number between 1 and 255.  Use nocbreak to leave half-
       delay mode.

       If the intrflush option is enabled, (bf is TRUE), when an interrupt key
       is pressed on the keyboard (interrupt, break, quit) all output in the
       tty driver queue will be flushed, giving the effect of faster response
       to the interrupt, but causing curses to have the wrong idea of what is
       on the screen.  Disabling (bf is FALSE), the option prevents the flush.
       The default for the option is inherited from the tty driver settings.
       The window argument is ignored.

       The keypad option enables the keypad of the user's terminal.  If
       enabled (bf is TRUE), the user can press a function key (such as an
       arrow key) and wgetch returns a single value representing the function
       key, as in KEY_LEFT.  If disabled (bf is FALSE), curses does not treat
       function keys specially and the program has to interpret the escape
       sequences itself.  If the keypad in the terminal can be turned on (made
       to transmit) and off (made to work locally), turning on this option
       causes the terminal keypad to be turned on when wgetch is called.  The
       default value for keypad is false.

       Initially, whether the terminal returns 7 or 8 significant bits on
       input depends on the control mode of the tty driver [see termio(7)].
       To force 8 bits to be returned, invoke meta(win, TRUE); this is
       equivalent, under POSIX, to setting the CS8 flag on the terminal.  To
       force 7 bits to be returned, invoke meta(win, FALSE); this is
       equivalent, under POSIX, to setting the CS7 flag on the terminal.  The
       window argument, win, is always ignored.  If the terminfo capabilities
       smm (meta_on) and rmm (meta_off) are defined for the terminal, smm is
       sent to the terminal when meta(win, TRUE) is called and rmm is sent
       when meta(win, FALSE) is called.

       The nodelay option causes getch to be a non-blocking call.  If no input
       is ready, getch returns ERR.  If disabled (bf is FALSE), getch waits
       until a key is pressed.

       While interpreting an input escape sequence, wgetch sets a timer while
       waiting for the next character.  If notimeout(win, TRUE) is called,
       then wgetch does not set a timer.  The purpose of the timeout is to
       differentiate between sequences received from a function key and those
       typed by a user.

       The raw and noraw routines place the terminal into or out of raw mode.
       Raw mode is similar to cbreak mode, in that characters typed are
       immediately passed through to the user program.  The differences are
       that in raw mode, the interrupt, quit, suspend, and flow control
       characters are all passed through uninterpreted, instead of generating
       a signal.  The behavior of the BREAK key depends on other bits in the
       tty driver that are not set by curses.

       When the noqiflush routine is used, normal flush of input and output
       queues associated with the INTR, QUIT and SUSP characters will not be
       done [see termio(7)].  When qiflush is called, the queues will be
       flushed when these control characters are read.  You may want to call
       noqiflush() in a signal handler if you want output to continue as
       though the interrupt had not occurred, after the handler exits.

       The timeout and wtimeout routines set blocking or non-blocking read for
       a given window.  If delay is negative, blocking read is used (i.e.,
       waits indefinitely for input).  If delay is zero, then non-blocking
       read is used (i.e., read returns ERR if no input is waiting).  If delay
       is positive, then read blocks for delay milliseconds, and returns ERR
       if there is still no input.  Hence, these routines provide the same
       functionality as nodelay, plus the additional capability of being able
       to block for only delay milliseconds (where delay is positive).

       The curses library does ``line-breakout optimization'' by looking for
       typeahead periodically while updating the screen.  If input is found,
       and it is coming from a tty, the current update is postponed until
       refresh or doupdate is called again.  This allows faster response to
       commands typed in advance.  Normally, the input FILE pointer passed to
       newterm, or stdin in the case that initscr was used, will be used to do
       this typeahead checking.  The typeahead routine specifies that the file
       descriptor fd is to be used to check for typeahead instead.  If fd is
       -1, then no typeahead checking is done.

       All routines that return an integer return ERR upon failure and OK
       (SVr4 specifies only "an integer value other than ERR") upon successful
       completion, unless otherwise noted in the preceding routine

       X/Open does not define any error conditions.  In this implementation,
       functions with a window parameter will return an error if it is null.
       Any function will also return an error if the terminal was not
       initialized.  Also,

                   returns an error if its parameter is outside the range

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

       The ncurses library obeys the XPG4 standard and the historical practice
       of the AT&T curses implementations, in that the echo bit is cleared
       when curses initializes the terminal state.  BSD curses differed from
       this slightly; it left the echo bit on at initialization, but the BSD
       raw call turned it off as a side-effect.  For best portability, set
       echo or noecho explicitly just after initialization, even if your
       program remains in cooked mode.

       Note that echo, noecho, halfdelay, intrflush, meta, nodelay, notimeout,
       noqiflush, qiflush, timeout, and wtimeout may be macros.

       The noraw and nocbreak calls follow historical practice in that they
       attempt to restore to normal (`cooked') mode from raw and cbreak modes
       respectively.  Mixing raw/noraw and cbreak/nocbreak calls leads to tty
       driver control states that are hard to predict or understand; it is not

       curses(3X), curs_getch(3X), curs_initscr(3X), termio(7)



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