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curs_inopts(3X)                                                                              curs_inopts(3X)



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

SYNOPSIS
       #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);

DESCRIPTION
       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 con-trol control
       trol 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 pro-gram program
       gram 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 rou-tines routines
       tines 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 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 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  func-tion function
       tion  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 termi-nal terminal
       nal 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 charac-ter. character.
       ter.  If notimeout(win, TRUE) is called, then wgetch does not set a timer.  The purpose of the  time-out timeout
       out 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 oth-er other
       er 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 han-dler handler
       dler if you want output to continue as though the interrupt had not occurred, after the  handler  ex-its. exits.
       its.

       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 nonblocking
       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  rou-tines routines
       tines  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.

RETURN VALUE
       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 parame-ter parameter
       ter will return an error if it is null.  Any function will also return an error if the  terminal  was
       not initialized.  Also,

              halfdelay
                   returns an error if its parameter is outside the range 1..255.

PORTABILITY
       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 implemen-tations, implementations,
       tations, in that the echo bit is cleared when curses initializes the terminal state.  BSD curses dif-fered differed
       fered  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.

NOTES
       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 recommended.

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



                                                                                             curs_inopts(3X)