Next: Inserting a character before the cursor, Previous: Getting a string of characters and attributes from a window, Up: The basic curses library [Contents][Index]
Normally, the TTY driver buffers typed characters until a NL or
RET 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.
These routines will return #t on success and #f on
failure. Failure may indicate that the underlying screen data is
invalid. The routine may also fail if cbreak! was called on an
ordinary file (such as might be used with newterm) instead of a
TTY.
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!.
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 Getting characters from the keyboard for a discussion of how these routines interact with
echo! and noecho!.
The return values are unspecified.
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, #f 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.
The return value is unspecified.
If the intrflush option is enabled, (bf is #t), 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 #f), the
option prevents the flush. The default for the option is inherited
from the TTY driver settings.
The return value is unspecified.
The keypad! option enables the keypad of the user’s terminal. If
enabled (bf is #t), the user can press a function key
(such as an arrow key) and getch returns a single value
representing the function key, as in KEY_LEFT. If disabled
(bf is #f), 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 getch is called. The default value
for keypad is #f.
The return value is unspecified. This procedure could throw a “bad state” error.
If Guile-Ncurses was compiled with the standard version of the ncurses library, and not the wide version, it operates on 8-bit characters.
Initially, whether the terminal returns 7 or 8 significant bits on
input depends on the control mode of the TTY driver. To force 8 bits
to be returned, invoke (meta! #t). This is equivalent,
under POSIX, to setting the CS8 flag on the terminal. To force 7 bits
to be returned, invoke (meta! #f). 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. The code for smm is sent to the
terminal when (meta! #t) is called and rmm is sent
when (meta! #f) is called.
The return value is unspecified.
The nodelay! option causes getch to be a non-blocking
call. If no input is ready, getch returns #f. If disabled
(bf is #f), getch waits until a key is pressed.
The return value is unspecified.
While interpreting an input escape sequence, getch sets a timer
while waiting for the next character. If (notimeout! win #t) is
called, then getch 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 return value is unspecified.
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 TTY driver that are not set by curses.
The return value is unspecified.
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. 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 return value is unspecified.
The timeout! routine sets 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 #f if no input is
waiting). If delay is positive, then read blocks for delay
milliseconds, and returns #f 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 getdelay procedure returns the timeout delay as set by
timeout!.
This procedure may not be present if the underlying version of ncurses does not support it.
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 port 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 (integer) file descriptor fd is to be used to
check for typeahead instead. If fd is -1, then no typeahead
checking is done.
The routine returns #t if the mode could be set and #f
on failure.
There are a set of procedures to test the input options of a given window.
These test the input options of the window win and return
#t if they are set.