Provided by: ncurses-doc_5.9+20140118-1ubuntu1_all bug

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 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 getch(3NCURSES) 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
       getch(3NCURSES) 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 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.

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  parameter
       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
       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.

       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.

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

       ncurses(3NCURSES), getch(3NCURSES), initscr(3NCURSES), util(3NCURSES), define_key(3NCURSES), termios(3)

                                                                                                inopts(3NCURSES)