1curs_inopts(3X) curs_inopts(3X)
2
6 cbreak, nocbreak, echo, noecho, halfdelay, intrflush, keypad, meta, nl,
7 nonl, nodelay, notimeout, raw, noraw, qiflush, noqiflush, timeout,
8 wtimeout, typeahead - curses input options
9
11 #include <curses.h>
12 int cbreak(void);
14 int nocbreak(void);
15 int echo(void);
17 int noecho(void);
18 int intrflush(WINDOW *win, bool bf);
20 int keypad(WINDOW *win, bool bf);
21 int meta(WINDOW *win, bool bf);
22 int nodelay(WINDOW *win, bool bf);
23 int notimeout(WINDOW *win, bool bf);
24 int nl(void);
26 int nonl(void);
27 int raw(void);
29 int noraw(void);
30 void qiflush(void);
32 void noqiflush(void);
33 int halfdelay(int tenths);
35 void timeout(int delay);
36 void wtimeout(WINDOW *win, int delay);
37 int typeahead(int fd);
39
41 The ncurses library provides several functions which let an application
42 change the way input from the terminal is handled. Some are global,
43 applying to all windows. Others apply only to a specific window. Win‐
44 dow-specific settings are not automatically applied to new or derived
45 windows. An application must apply these to each window, if the same
46 behavior is needed.
47 cbreak/nocbreak
49 Normally, the tty driver buffers typed characters until a newline or
50 carriage return is typed. The cbreak routine disables line buffering
51 and erase/kill character-processing (interrupt and flow control charac‐
52 ters are unaffected), making characters typed by the user immediately
53 available to the program. The nocbreak routine returns the terminal to
54 normal (cooked) mode.
55 Initially the terminal may or may not be in cbreak mode, as the mode is
57 inherited; therefore, a program should call cbreak or nocbreak explic‐
58 itly. Most interactive programs using curses set the cbreak mode.
59 Note that cbreak overrides raw. [See curs_getch(3X) for a discussion
60 of how these routines interact with echo and noecho.]
61 echo/noecho
63 The echo and noecho routines control whether characters typed by the
64 user are echoed by getch(3X) as they are typed. Echoing by the tty
65 driver is always disabled, but initially getch is in echo mode, so
66 characters typed are echoed. Authors of most interactive programs pre‐
67 fer to do their own echoing in a controlled area of the screen, or not
68 to echo at all, so they disable echoing by calling noecho. [See
69 curs_getch(3X) for a discussion of how these routines interact with
70 cbreak and nocbreak.]
71 halfdelay
73 The halfdelay routine is used for half-delay mode, which is similar to
74 cbreak mode in that characters typed by the user are immediately avail‐
75 able to the program. However, after blocking for tenths tenths of sec‐
76 onds, ERR is returned if nothing has been typed. The value of tenths
77 must be a number between 1 and 255. Use nocbreak to leave half-delay
78 mode.
79 intrflush
81 If the intrflush option is enabled (bf is TRUE), and an interrupt key
82 is pressed on the keyboard (interrupt, break, quit), all output in the
83 tty driver queue will be flushed, giving the effect of faster response
84 to the interrupt, but causing curses to have the wrong idea of what is
85 on the screen. Disabling the option (bf is FALSE) prevents the flush.
86 The default for the option is inherited from the tty driver settings.
87 The window argument is ignored.
88 keypad
90 The keypad option enables the keypad of the user's terminal. If en‐
91 abled (bf is TRUE), the user can press a function key (such as an arrow
92 key) and wgetch(3X) returns a single value representing the function
93 key, as in KEY_LEFT. If disabled (bf is FALSE), curses does not treat
94 function keys specially and the program has to interpret the escape se‐
95 quences itself. If the keypad in the terminal can be turned on (made
96 to transmit) and off (made to work locally), turning on this option
97 causes the terminal keypad to be turned on when wgetch(3X) is called.
98 The default value for keypad is FALSE.
99 meta
101 Initially, whether the terminal returns 7 or 8 significant bits on in‐
102 put depends on the control mode of the tty driver [see termios(3)]. To
103 force 8 bits to be returned, invoke meta(win, TRUE); this is equiva‐
104 lent, under POSIX, to setting the CS8 flag on the terminal. To force 7
105 bits to be returned, invoke meta(win, FALSE); this is equivalent, under
106 POSIX, to setting the CS7 flag on the terminal. The window argument,
107 win, is always ignored. If the terminfo capabilities smm (meta_on) and
108 rmm (meta_off) are defined for the terminal, smm is sent to the termi‐
109 nal when meta(win, TRUE) is called and rmm is sent when meta(win,
110 FALSE) is called.
111 nl/nonl
113 The nl and nonl routines control whether the underlying display device
114 translates the return key into newline on input.
115 nodelay
117 The nodelay option causes getch to be a non-blocking call. If no input
118 is ready, getch returns ERR. If disabled (bf is FALSE), getch waits
119 until a key is pressed.
120 notimeout
122 When interpreting an escape sequence, wgetch(3X) sets a timer while
123 waiting for the next character. If notimeout(win, TRUE) is called,
124 then wgetch does not set a timer. The purpose of the timeout is to
125 differentiate between sequences received from a function key and those
126 typed by a user.
127 raw/noraw
129 The raw and noraw routines place the terminal into or out of raw mode.
130 Raw mode is similar to cbreak mode, in that characters typed are imme‐
131 diately passed through to the user program. The differences are that
132 in raw mode, the interrupt, quit, suspend, and flow control characters
133 are all passed through uninterpreted, instead of generating a signal.
134 The behavior of the BREAK key depends on other bits in the tty driver
135 that are not set by curses.
136 qiflush/noqiflush
138 When the noqiflush routine is used, normal flush of input and output
139 queues associated with the INTR, QUIT and SUSP characters will not be
140 done [see termios(3)]. When qiflush is called, the queues will be
141 flushed when these control characters are read. You may want to call
142 noqiflush in a signal handler if you want output to continue as though
143 the interrupt had not occurred, after the handler exits.
144 timeout/wtimeout
146 The timeout and wtimeout routines set blocking or non-blocking read for
147 a given window. If delay is negative, blocking read is used (i.e.,
148 waits indefinitely for input). If delay is zero, then non-blocking
149 read is used (i.e., read returns ERR if no input is waiting). If delay
150 is positive, then read blocks for delay milliseconds, and returns ERR
151 if there is still no input. Hence, these routines provide the same
152 functionality as nodelay, plus the additional capability of being able
153 to block for only delay milliseconds (where delay is positive).
154 typeahead
156 The curses library does “line-breakout optimization” by looking for ty‐
157 peahead periodically while updating the screen. If input is found, and
158 it is coming from a tty, the current update is postponed until re‐
159 fresh(3X) or doupdate is called again. This allows faster response to
160 commands typed in advance. Normally, the input FILE pointer passed to
161 newterm, or stdin in the case that initscr was used, will be used to do
162 this typeahead checking. The typeahead routine specifies that the file
163 descriptor fd is to be used to check for typeahead instead. If fd is
164 -1, then no typeahead checking is done.
165
167 All routines that return an integer return ERR upon failure and OK
168 (SVr4 specifies only “an integer value other than ERR”) upon successful
169 completion, unless otherwise noted in the preceding routine descrip‐
170 tions.
171 X/Open does not define any error conditions. In this implementation,
173 functions with a window parameter will return an error if it is null.
174 Any function will also return an error if the terminal was not initial‐
175 ized. Also,
176 halfdelay
178 returns an error if its parameter is outside the range
179 1..255.
180
182 These functions are described in the XSI Curses standard, Issue 4.
183 The ncurses library obeys the XPG4 standard and the historical practice
185 of the AT&T curses implementations, in that the echo bit is cleared
186 when curses initializes the terminal state. BSD curses differed from
187 this slightly; it left the echo bit on at initialization, but the BSD
188 raw call turned it off as a side-effect. For best portability, set
189 echo or noecho explicitly just after initialization, even if your pro‐
190 gram remains in cooked mode.
191 The XSI Curses standard is ambiguous on the question of whether raw
193 should disable the CRLF translations controlled by nl and nonl. BSD
194 curses did turn off these translations; AT&T curses (at least as late
195 as SVr1) did not. We chose to do so, on the theory that a programmer
196 requesting raw input wants a clean (ideally 8-bit clean) connection
197 that the operating system will not alter.
198 When keypad is first enabled, ncurses loads the key-definitions for the
200 current terminal description. If the terminal description includes ex‐
201 tended string capabilities, e.g., from using the -x option of tic, then
202 ncurses also defines keys for the capabilities whose names begin with
203 “k”. The corresponding keycodes are generated and (depending on previ‐
204 ous loads of terminal descriptions) may differ from one execution of a
205 program to the next. The generated keycodes are recognized by the key‐
206 name function (which will then return a name beginning with “k” denot‐
207 ing the terminfo capability name rather than “K”, used for curses key-
208 names). On the other hand, an application can use define_key to estab‐
209 lish a specific keycode for a given string. This makes it possible for
210 an application to check for an extended capability's presence with
211 tigetstr, and reassign the keycode to match its own needs.
212 Low-level applications can use tigetstr to obtain the definition of any
214 particular string capability. Higher-level applications which use the
215 curses wgetch and similar functions to return keycodes rely upon the
216 order in which the strings are loaded. If more than one key definition
217 has the same string value, then wgetch can return only one keycode.
218 Most curses implementations (including ncurses) load key definitions in
219 the order defined by the array of string capability names. The last
220 key to be loaded determines the keycode which will be returned. In
221 ncurses, you may also have extended capabilities interpreted as key
222 definitions. These are loaded after the predefined keys, and if a ca‐
223 pability's value is the same as a previously-loaded key definition, the
224 later definition is the one used.
225
227 Note that echo, noecho, halfdelay, intrflush, meta, nl, nonl, nodelay,
228 notimeout, noqiflush, qiflush, timeout, and wtimeout may be macros.
229 The noraw and nocbreak calls follow historical practice in that they
231 attempt to restore to normal (“cooked”) mode from raw and cbreak modes
232 respectively. Mixing raw/noraw and cbreak/nocbreak calls leads to tty
233 driver control states that are hard to predict or understand; it is not
234 recommended.
235
237 curses(3X), curs_getch(3X), curs_initscr(3X), curs_util(3X), de‐
238 fine_key(3X), termios(3)
239 curs_inopts(3X)