CURS_INOPTS(3X-SVR4)RISC/os Reference Manual CURS_INOPTS(3X-SVR4)
NAME
curs_inopts: cbreak, nocbreak, echo, noecho, halfdelay,
intrflush, keypad, meta, nodelay, notimeout, raw,
noraw, noqiflush, qiflush, timeout, wtimeout, typeahead
- curses terminal input option control routines
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 notimeout(WINDOW *win, bool bf);
int raw(void);
int noraw(void);
void noqiflush(void);
void qiflush(void);
void timeout(int delay);
void wtimeout(WINDOW *win, int delay);
int typeahead(int fd);
DESCRIPTION
The cbreak and nocbreak routines put the terminal into and
out of cbreak mode, respectively. In this mode, characters
typed by the user are immediately available to the program,
and erase/kill character-processing is not performed. When
out of this mode, the tty driver buffers the typed charac-
ters until a newline or carriage return is typed. Interrupt
and flow control characters are unaffected by this 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 noe-
cho.]
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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 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). To force 7 bits to be returned, invoke
meta(win, FALSE). 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.
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CURS_INOPTS(3X-SVR4)RISC/os Reference Manual CURS_INOPTS(3X-SVR4)
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.
With the raw and noraw routines, the terminal is placed 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.
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 capabil-
ity of being able to block for only delay milliseconds
(where delay is positive).
curses does line-breakout optimization by looking for typea-
head 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. Nor-
mally, 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 an integer value other than ERR upon successful comple-
tion, unless otherwise noted in the preceding routine
descriptions.
NOTES
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CURS_INOPTS(3X-SVR4)RISC/os Reference Manual CURS_INOPTS(3X-SVR4)
The header file <curses.h> automatically includes the header
files <stdio.h> and <unctrl.h>.
Note that echo, noecho, halfdelay, intrflush, meta, nodelay,
notimeout, noqiflush, qiflush, timeout, and wtimeout may be
macros.
SEE ALSO
curses(3X), curs_getch(3X), curs_initscr(3X), termio(7).
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