Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
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 charac-
       ters 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 explic-
       itly.  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	avail-
       able to the program.  However, after blocking for tenths	tenths of sec-
       onds, 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), 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  en-
       abled (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 func-
       tion keys specially and the program has to  interpret  the  escape  se-
       quences	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  in-
       put  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  equiva-
       lent, 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	termi-
       nal 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	 imme-
       diately	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 ty-
       peahead 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 ty-
       peahead	checking.   The	 typeahead routine specifies that the file de-
       scriptor	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 descrip-

       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 initial-
       ized.  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 pro-
       gram remains in cooked mode.

       When keypad is first enabled, ncurses loads the key-definitions for the
       current terminal	description.  If the terminal description includes ex-
       tended 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	previ-
       ous  loads of terminal descriptions) may	differ from one	execution of a
       program to the next.  The generated keycodes are	recognized by the key-
       name  function (which will then return a	name beginning with "k"	denot-
       ing the terminfo	capability name	rather than "K", used for curses  key-
       names).	On the other hand, an application can use define_key to	estab-
       lish 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 ca-
       pability'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, 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),   de-
       fine_key(3X), termio(7)



Want to link to this manual page? Use this URL:

home | help