- 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-process-
- ing (interrupt and flow control characters are unaffect-
- ed), 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 over-
- rides 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 initial-
- ly 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 re-
- turned 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 in-
- terrupt, 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 inher-
- ited from the tty driver settings. The window argument is
- ignored.
-
- The keypad option enables the keypad of the user's termi-
- nal. If enabled (bf is TRUE), the user can press a func-
- tion key (such as an arrow key) and wgetch returns a sin-
- gle 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 local-
- ly), 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 driv-
- er [see termio(7)]. To force 8 bits to be returned, in-
- voke 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 notime-
- out(win, TRUE) is called, then wgetch does not set a
- timer. The purpose of the timeout is to differentiate be-
- tween 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 us-
- er program. The differences are that in raw mode, the in-
- terrupt, 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 in-
- put). 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 rou-
- tines provide the same functionality as nodelay, plus the
- additional capability of being able to block for only de-
- lay 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.
+ intintrflush(WINDOW*win,boolbf);
+ intkeypad(WINDOW*win,boolbf);
+ intmeta(WINDOW*win,boolbf);
+ intnodelay(WINDOW*win,boolbf);
+ intnotimeout(WINDOW*win,boolbf);
+ intnl(void);
+ intnonl(void);
-
-
RETURN VALUE
- All routines that return an integer return ERR upon fail-
- ure 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 im-
- plementation, functions with a window parameter will re-
- turn an error if it is null. Any function will also re-
- turn an error if the terminal was not initialized. Also,
+ intraw(void);
+ intnoraw(void);
- halfdelay
- returns an error if its parameter is outside
- the range 1..255.
+ voidqiflush(void);
+ voidnoqiflush(void);
+ inthalfdelay(inttenths);
+ voidtimeout(intdelay);
+ voidwtimeout(WINDOW*win,intdelay);
+
+ inttypeahead(intfd);
+
+ /*extensions*/
+ intis_cbreak(void);
+ intis_echo(void);
+ intis_nl(void);
+ intis_raw(void);
+
+
+
+ ncurses provides several functions that 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
+ desired.
+
+
+
+ Normally, the terminal 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
+ terminal 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.]
-
-
PORTABILITY
- These functions are described in the XSI Curses standard,
- Issue 4.
- The ncurses library obeys the XPG4 standard and the his-
- torical 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 portabili-
- ty, set echo or noecho explicitly just after initializa-
- tion, even if your program remains in cooked mode.
+
+ 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), and an interrupt key
+ is pressed on the keyboard (interrupt, break, quit), all output in the
+ terminal driver queue is 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 terminal driver
+ settings. The win 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 terminal 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 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.
+
+
+
+ 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
+ distinguish sequences produced by a function key from 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
+ terminal 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.
-
-
NOTES
- Note that echo, noecho, halfdelay, intrflush, meta, node-
- lay, 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
+
+ The timeout and wtimeout routines set blocking or non-blocking read for
+ a given window. If delay is negative, a blocking read is used (i.e.,
+ waits indefinitely for input). If delay is zero, then a 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).
+
+
+
+ curses does "line-breakout optimization" by looking for typeahead
+ periodically while updating the screen. If input is found, and it is
+ coming from a terminal, 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 Curses does not specify 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.
+
+
+
+ echo, noecho, halfdelay, intrflush, meta, nl, nonl, nodelay, notimeout,
+ noqiflush, qiflush, timeout, and wtimeout may be implemented as macros.
+
+ noraw and nocbreak follow historical practice in that they attempt to
+ restore normal ("cooked") mode from raw and cbreak modes respectively.
+ Mixing raw/noraw and cbreak/nocbreak calls leads to terminal driver
+ control states that are hard to predict or understand; doing so is not
recommended.
+
+ ncurses provides four "is_" functions that may be used to detect if the
+ corresponding flags were set or reset.
+
+ QuerySetReset
+ ------------------------------
+ is_cbreak cbreak nocbreak
+ is_echo echo noecho
+ is_nl nl nonl
+ is_raw raw noraw
+
+ In each case, the function returns
+
+ 1 if the flag is set,
+
+ 0 if the flag is reset, or
+
+ -1 if the library is not initialized.
+
+ They were designed for ncurses(3x), and are not found in SVr4 curses,
+ 4.4BSD curses, or any other previous curses implementation.
+
+
+
+ Applications employing ncurses extensions should condition their use on
+ the visibility of the NCURSES_VERSION preprocessor macro.
+
+ Except as noted in section "EXTENSIONS" above, X/Open Curses, Issue 4,
+ Version 2 describes these functions.
+
+ ncurses follows X/Open Curses and the historical practice of 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.
+
+ X/Open Curses is ambiguous regarding whether raw should disable the
+ CR/LF translations controlled by nl and nonl. BSD curses did turn off
+ these translations; AT&T curses (at least as late as SVr1) did not.
+ ncurses does so, on the assumption 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(3x) 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(3x)
+ 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
+ curseswgetch 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.
+
+
+
+ Formerly, ncurses used nl and nonl to control the conversion of
+ newlines to carriage return/line feed on output as well as input.
+ X/Open Curses documents the use of these functions only for input.
+ This difference arose from converting the pcurses source (1986), which
+ used ioctl(2) calls and the sgttyb structure, to termios (the POSIX
+ terminal API). In the former, both input and output were controlled
+ via a single option CRMOD, while the latter separates these features.
+ Because that conversion interferes with output optimization, ncurses
+ 6.2 (2020) amended nl and nonl to eliminate their effect on output.
+
+
+