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* @Id: curs_inopts.3x,v 1.19 2015/04/11 10:21:38 tom Exp @
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<H1 class="no-header">curs_inopts 3x</H1>
<STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG> <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>
<H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>cbreak</STRONG>, <STRONG>nocbreak</STRONG>, <STRONG>echo</STRONG>, <STRONG>noecho</STRONG>, <STRONG>halfdelay</STRONG>, <STRONG>intrflush</STRONG>,
<STRONG>keypad</STRONG>, <STRONG>meta</STRONG>, <STRONG>nodelay</STRONG>, <STRONG>notimeout</STRONG>, <STRONG>raw</STRONG>, <STRONG>noraw</STRONG>, <STRONG>noqiflush</STRONG>,
<STRONG>qiflush</STRONG>, <STRONG>timeout</STRONG>, <STRONG>wtimeout</STRONG>, <STRONG>typeahead</STRONG> - <STRONG>curses</STRONG> input
<H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
<STRONG>int</STRONG> <STRONG>cbreak(void);</STRONG>
<STRONG>int</STRONG> <STRONG>nocbreak(void);</STRONG>
<STRONG>int</STRONG> <STRONG>echo(void);</STRONG>
<STRONG>int</STRONG> <STRONG>noecho(void);</STRONG>
<STRONG>int</STRONG> <STRONG>halfdelay(int</STRONG> <STRONG>tenths);</STRONG>
<STRONG>int</STRONG> <STRONG>raw(void);</STRONG>
<STRONG>int</STRONG> <STRONG>noraw(void);</STRONG>
<STRONG>void</STRONG> <STRONG>noqiflush(void);</STRONG>
<STRONG>void</STRONG> <STRONG>qiflush(void);</STRONG>
<STRONG>void</STRONG> <STRONG>timeout(int</STRONG> <STRONG>delay);</STRONG>
<STRONG>int</STRONG> <STRONG>typeahead(int</STRONG> <STRONG>fd);</STRONG>
<H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
The <STRONG>ncurses</STRONG> library provides several functions which let
an application change way input from the terminal is han-
dled. 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.
<H3><a name="h3-cbreak">cbreak</a></H3><PRE>
Normally, the tty driver buffers typed characters until a
newline or carriage return is typed. The <STRONG>cbreak</STRONG> routine
disables line buffering and erase/kill character-process-
ing (interrupt and flow control characters are unaffect-
ed), making characters typed by the user immediately
available to the program. The <STRONG>nocbreak</STRONG> routine returns
the terminal to normal (cooked) mode.
Initially the terminal may or may not be in <STRONG>cbreak</STRONG> mode,
as the mode is inherited; therefore, a program should call
<STRONG>cbreak</STRONG> or <STRONG>nocbreak</STRONG> explicitly. Most interactive programs
using <STRONG>curses</STRONG> set the <STRONG>cbreak</STRONG> mode. Note that <STRONG>cbreak</STRONG> over-
rides <STRONG>raw</STRONG>. [See <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG> for a discussion of how
these routines interact with <STRONG>echo</STRONG> and <STRONG>noecho</STRONG>.]
<H3><a name="h3-echo_noecho">echo/noecho</a></H3><PRE>
The <STRONG>echo</STRONG> and <STRONG>noecho</STRONG> routines control whether characters
typed by the user are echoed by <STRONG>getch</STRONG> as they are typed.
Echoing by the tty driver is always disabled, but initial-
ly <STRONG>getch</STRONG> 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 <STRONG>noecho</STRONG>.
[See <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG> for a discussion of how these routines
interact with <STRONG>cbreak</STRONG> and <STRONG>nocbreak</STRONG>.]
<H3><a name="h3-halfdelay">halfdelay</a></H3><PRE>
The <STRONG>halfdelay</STRONG> routine is used for half-delay mode, which
is similar to <STRONG>cbreak</STRONG> mode in that characters typed by the
user are immediately available to the program. However,
after blocking for <EM>tenths</EM> tenths of seconds, ERR is re-
turned if nothing has been typed. The value of <STRONG>tenths</STRONG>
must be a number between 1 and 255. Use <STRONG>nocbreak</STRONG> to leave
half-delay mode.
<H3><a name="h3-intrflush">intrflush</a></H3><PRE>
If the <STRONG>intrflush</STRONG> option is enabled, (<EM>bf</EM> is <STRONG>TRUE</STRONG>), 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 in-
terrupt, but causing <STRONG>curses</STRONG> to have the wrong idea of what
is on the screen. Disabling (<EM>bf</EM> is <STRONG>FALSE</STRONG>), the option
prevents the flush. The default for the option is inher-
ited from the tty driver settings. The window argument is
<H3><a name="h3-keypad">keypad</a></H3><PRE>
The <STRONG>keypad</STRONG> option enables the keypad of the user's termi-
nal. If enabled (<EM>bf</EM> is <STRONG>TRUE</STRONG>), the user can press a func-
tion key (such as an arrow key) and <STRONG>wgetch</STRONG> returns a sin-
gle value representing the function key, as in <STRONG>KEY_LEFT</STRONG>.
If disabled (<EM>bf</EM> is <STRONG>FALSE</STRONG>), <STRONG>curses</STRONG> 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 local-
ly), turning on this option causes the terminal keypad to
be turned on when <STRONG>wgetch</STRONG> is called. The default value for
<H3><a name="h3-meta">meta</a></H3><PRE>
Initially, whether the terminal returns 7 or 8 significant
bits on input depends on the control mode of the tty driv-
er [see <STRONG>termio(7)</STRONG>]. To force 8 bits to be returned, in-
voke <STRONG>meta</STRONG>(<EM>win</EM>, <STRONG>TRUE</STRONG>); this is equivalent, under POSIX, to
setting the CS8 flag on the terminal. To force 7 bits to
be returned, invoke <STRONG>meta</STRONG>(<EM>win</EM>, <STRONG>FALSE</STRONG>); this is equivalent,
under POSIX, to setting the CS7 flag on the terminal. The
window argument, <EM>win</EM>, is always ignored. If the terminfo
capabilities <STRONG>smm</STRONG> (meta_on) and <STRONG>rmm</STRONG> (meta_off) are defined
for the terminal, <STRONG>smm</STRONG> is sent to the terminal when
<STRONG>meta</STRONG>(<EM>win</EM>, <STRONG>TRUE</STRONG>) is called and <STRONG>rmm</STRONG> is sent when <STRONG>meta</STRONG>(<EM>win</EM>,
<STRONG>FALSE</STRONG>) is called.
<H3><a name="h3-nodelay">nodelay</a></H3><PRE>
The <STRONG>nodelay</STRONG> option causes <STRONG>getch</STRONG> to be a non-blocking call.
If no input is ready, <STRONG>getch</STRONG> returns <STRONG>ERR</STRONG>. If disabled (<EM>bf</EM>
is <STRONG>FALSE</STRONG>), <STRONG>getch</STRONG> waits until a key is pressed.
While interpreting an input escape sequence, <STRONG>wgetch</STRONG> sets a
timer while waiting for the next character. If <STRONG>notime-</STRONG>
<STRONG>out(</STRONG><EM>win</EM>, <STRONG>TRUE</STRONG>) is called, then <STRONG>wgetch</STRONG> does not set a
timer. The purpose of the timeout is to differentiate be-
tween sequences received from a function key and those
typed by a user.
<H3><a name="h3-raw_noraw">raw/noraw</a></H3><PRE>
The <STRONG>raw</STRONG> and <STRONG>noraw</STRONG> routines place the terminal into or out
of raw mode. Raw mode is similar to <STRONG>cbreak</STRONG> mode, in that
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 <STRONG>curses</STRONG>.
<H3><a name="h3-noqiflush">noqiflush</a></H3><PRE>
When the <STRONG>noqiflush</STRONG> routine is used, normal flush of input
and output queues associated with the <STRONG>INTR</STRONG>, <STRONG>QUIT</STRONG> and <STRONG>SUSP</STRONG>
characters will not be done [see <STRONG>termio(7)</STRONG>]. When <STRONG>qiflush</STRONG>
is called, the queues will be flushed when these control
characters are read. You may want to call <STRONG>noqiflush()</STRONG> in
a signal handler if you want output to continue as though
the interrupt had not occurred, after the handler exits.
<H3><a name="h3-timeout_wtimeout">timeout/wtimeout</a></H3><PRE>
The <STRONG>timeout</STRONG> and <STRONG>wtimeout</STRONG> routines set blocking or non-
blocking read for a given window. If <EM>delay</EM> is negative,
blocking read is used (i.e., waits indefinitely for in-
put). If <EM>delay</EM> is zero, then non-blocking read is used
(i.e., read returns <STRONG>ERR</STRONG> if no input is waiting). If <EM>delay</EM>
is positive, then read blocks for <EM>delay</EM> milliseconds, and
returns <STRONG>ERR</STRONG> if there is still no input. Hence, these rou-
tines provide the same functionality as <STRONG>nodelay</STRONG>, plus the
additional capability of being able to block for only <EM>de-</EM>
<EM>lay</EM> milliseconds (where <EM>delay</EM> is positive).
<H3><a name="h3-typeahead">typeahead</a></H3><PRE>
The <STRONG>curses</STRONG> 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 <STRONG>refresh</STRONG> or <STRONG>doupdate</STRONG>
is called again. This allows faster response to commands
typed in advance. Normally, the input FILE pointer passed
to <STRONG>newterm</STRONG>, or <STRONG>stdin</STRONG> in the case that <STRONG>initscr</STRONG> was used,
will be used to do this typeahead checking. The <STRONG>typeahead</STRONG>
routine specifies that the file descriptor <EM>fd</EM> is to be
used to check for typeahead instead. If <EM>fd</EM> is -1, then no
typeahead checking is done.
<H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
All routines that return an integer return <STRONG>ERR</STRONG> upon fail-
ure and OK (SVr4 specifies only "an integer value other
than <STRONG>ERR</STRONG>") 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,
returns an error if its parameter is outside
the range 1..255.
<H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
These functions are described in the XSI Curses standard,
Issue 4.
The ncurses library obeys the XPG4 standard and the his-
torical practice of the AT&amp;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 <STRONG>raw</STRONG>
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 <STRONG>keypad</STRONG> 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 <STRONG>-x</STRONG> 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 <STRONG>keyname</STRONG> 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 <STRONG>define_key</STRONG> 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 <EM>tigetstr</EM>,
and reassign the keycode to match its own needs.
Low-level applications can use <STRONG>tigetstr</STRONG> to obtain the def-
inition of any particular string capability. Higher-level
applications which use the curses <STRONG>wgetch</STRONG> 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 <STRONG>wgetch</STRONG> 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
<H2><a name="h2-NOTES">NOTES</a></H2><PRE>
Note that <STRONG>echo</STRONG>, <STRONG>noecho</STRONG>, <STRONG>halfdelay</STRONG>, <STRONG>intrflush</STRONG>, <STRONG>meta</STRONG>, <STRONG>node-</STRONG>
<STRONG>lay</STRONG>, <STRONG>notimeout</STRONG>, <STRONG>noqiflush</STRONG>, <STRONG>qiflush</STRONG>, <STRONG>timeout</STRONG>, and <STRONG>wtimeout</STRONG>
may be macros.
The <STRONG>noraw</STRONG> and <STRONG>nocbreak</STRONG> 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
<H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>,
<STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>, <STRONG><A HREF="define_key.3x.html">define_key(3x)</A></STRONG>, <STRONG>termio(7)</STRONG>
<STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>
<div class="nav">
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<li><a href="#h3-cbreak">cbreak</a></li>
<li><a href="#h3-echo_noecho">echo/noecho</a></li>
<li><a href="#h3-halfdelay">halfdelay</a></li>
<li><a href="#h3-intrflush">intrflush</a></li>
<li><a href="#h3-keypad">keypad</a></li>
<li><a href="#h3-meta">meta</a></li>
<li><a href="#h3-nodelay">nodelay</a></li>
<li><a href="#h3-raw_noraw">raw/noraw</a></li>
<li><a href="#h3-noqiflush">noqiflush</a></li>
<li><a href="#h3-timeout_wtimeout">timeout/wtimeout</a></li>
<li><a href="#h3-typeahead">typeahead</a></li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>