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curs_inopts(3)                                                  curs_inopts(3)


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


       #include <curses.h>

       int cbreak(void);
       int nocbreak(void);

       int echo(void);
       int noecho(void);

       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 notimeout(WINDOW *win, bool bf);

       int nl(void);
       int nonl(void);

       int raw(void);
       int noraw(void);

       void qiflush(void);
       void noqiflush(void);

       int halfdelay(int tenths);
       void timeout(int delay);
       void wtimeout(WINDOW *win, int delay);

       int typeahead(int fd);


       The ncurses library provides several functions which let an application
       change the way input from the terminal is handled.  Some are global,
       applying to all windows.  Others apply only to a specific window.
       Window-specific settings are not automatically applied to new or derived
       windows.  An application must apply these to each window, if the same
       behavior is needed.

       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(3X) 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 nocbreak.]

       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

       If the intrflush option is enabled (bf is TRUE), and 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 the option (bf is FALSE) 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(3X) 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(3X) 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 termios(3)].  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

       The nl and nonl routines control whether the underlying display device
       translates the return key into newline on input.

       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.

       When interpreting an escape sequence, wgetch(3X) 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 termios(3)].  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(3X) 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 descriptions.

       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.

       The XSI Curses standard is ambiguous on the question of whether raw
       should disable the CRLF translations controlled by nl and nonl.  BSD
       curses did turn off these translations; AT&T curses (at least as late as
       SVr1) did not.  We chose to do so, on the theory that a programmer
       requesting raw input wants a clean (ideally 8-bit clean) connection that
       the operating system will not alter.

       When keypad is first enabled, ncurses loads the key-definitions for the
       current terminal description.  If the terminal description includes
       extended string capabilities, e.g., from using the -x option of tic, then
       ncurses also defines keys for the capabilities whose names begin with
       "k".  The corresponding keycodes are generated and (depending on previous
       loads of terminal descriptions) may differ from one execution of a
       program to the next.  The generated keycodes are recognized by the
       keyname function (which will then return a name beginning with "k"
       denoting the terminfo capability name rather than "K", used for curses
       key-names).  On the other hand, an application can use define_key to
       establish a specific keycode for a given string.  This makes it possible
       for an application to check for an extended capability's presence with
       tigetstr, and reassign the keycode to match its own needs.

       Low-level applications can use tigetstr to obtain the definition of any
       particular string capability.  Higher-level applications which use the
       curses wgetch and similar functions to return keycodes rely upon the
       order in which the strings are loaded.  If more than one key definition
       has the same string value, then wgetch can return only one keycode.  Most
       curses implementations (including ncurses) load key definitions in the
       order defined by the array of string capability names.  The last key to
       be loaded determines the keycode which will be returned.  In ncurses, you
       may also have extended capabilities interpreted as key definitions.
       These are loaded after the predefined keys, and if a capability's value
       is the same as a previously-loaded key definition, the later definition
       is the one used.


       Note that echo, noecho, halfdelay, intrflush, meta, nl, nonl, 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), curs_util(3X),
       define_key(3X), termios(3)


ncurses 6.4 - Generated Tue Jan 3 15:41:48 CST 2023
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