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 unaf-
- fected), making characters typed by the user immediately
+ 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.
@@ -95,31 +96,31 @@
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 ini-
- tially 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.]
+ 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
- returned if nothing has been typed. The value of tenths
+ 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
- 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 argu-
- ment is ignored.
+ 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-
@@ -128,21 +129,21 @@
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 key-
- pad to be turned on when wgetch is called. The default
- value for keypad is false.
+ 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
- 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 equiva-
- lent, under POSIX, to setting the CS7 flag on the termi-
- nal. 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
+ 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.
@@ -153,22 +154,22 @@
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
- between sequences received from a function key and those
+ 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
- user program. The differences are that in raw mode, the
- interrupt, quit, suspend, and flow control characters are
+ 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
+ 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
@@ -176,16 +177,16 @@
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
+ 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
- delay milliseconds (where delay is positive).
+ additional capability of being able to block for only de-
+ lay milliseconds (where delay is positive).
- The curses library does ``line-breakout optimization'' by
+ 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
@@ -199,15 +200,24 @@
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,
+
+ halfdelay
+ returns an error if its parameter is outside
+ the range 1..255.
+
These functions are described in the XSI Curses standard,
Issue 4.
@@ -216,37 +226,77 @@
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 portabil-
- ity, set echo or noecho explicitly just after initializa-
+ 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.
+ When keypad is first enabled, ncurses loads the key-defi-
+ nitions for the current terminal description. If the ter-
+ minal 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 (de-
+ pending 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 def-
+ inition of any particular string capability. Higher-level
+ applications which use the curses wgetch and similar func-
+ tions 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 deter-
+ mines 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, node-
- lay, notimeout, noqiflush, qiflush, timeout, and wtimeout
+
+ 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
+ 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.