параметры ввода библиотеки Curses (curses input options)
Имя (Name)
cbreak, nocbreak, echo, noecho, halfdelay, intrflush, keypad,
meta, nl, nonl, nodelay, notimeout, raw, noraw, qiflush,
noqiflush, timeout, wtimeout, typeahead - curses input options
Синопсис (Synopsis)
#include <curses.h>
int cbreak(void);
int nocbreak(void);
int echo(void);
int noecho(void);
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 nl(void);
int nonl(void);
int raw(void);
int noraw(void);
void qiflush(void);
void noqiflush(void);
int halfdelay(int tenths);
void timeout(int delay);
void wtimeout(WINDOW *win, int delay);
int typeahead(int fd);
Описание (Description)
The ncurses library provides several functions which 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 needed.
cbreak/nocbreak
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-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.]
echo/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 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.]
halfdelay
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.
intrflush
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 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 the option
(bf is FALSE) prevents the flush. The default for the option is
inherited from the tty driver settings. The window argument is
ignored.
keypad
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.
meta
Initially, whether the terminal returns 7 or 8 significant bits
on input depends on the control mode of the tty 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.
nl/nonl
The nl and nonl routines control whether the underlying display
device translates the return key into newline on input.
nodelay
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.
notimeout
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 differentiate between sequences received from a
function key and those typed by a user.
raw/noraw
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.
qiflush/noqiflush
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.
timeout/wtimeout
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 capability of being able to block for only
delay milliseconds (where delay is positive).
typeahead
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(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.
Возвращаемое значение (Return value)
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 does not define 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.
Портативность (Portability)
These functions are described in the XSI Curses standard, Issue
4.
The ncurses library obeys the XPG4 standard and the historical
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 portability, set echo or noecho explicitly just
after initialization, even if your program remains in cooked
mode.
The XSI Curses standard is ambiguous on the question of whether
raw should disable the CRLF translations controlled by nl and
nonl. BSD curses did turn off these translations; AT&T curses
(at least as late as SVr1) did not. We chose to do so, on the
theory 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 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 definition
of any particular string capability. Higher-level applications
which use the curses wgetch 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.
Примечание (Note)
Note that echo, noecho, halfdelay, intrflush, meta, nl, nonl,
nodelay, 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 recommended.
Смотри также (See also)
curses(3X), curs_getch(3X), curs_initscr(3X), curs_util(3X),
define_key(3X), termios(3)
