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<H1 class="no-header">curs_inopts 3x 2025-10-04 ncurses 6.6 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>cbreak</STRONG>, <STRONG>echo</STRONG>, <STRONG>halfdelay</STRONG>, <STRONG>intrflush</STRONG>, <STRONG>is_cbreak</STRONG>, <STRONG>is_echo</STRONG>, <STRONG>is_nl</STRONG>, <STRONG>is_raw</STRONG>,
<STRONG>keypad</STRONG>, <STRONG>meta</STRONG>, <STRONG>nl</STRONG>, <STRONG>nocbreak</STRONG>, <STRONG>nodelay</STRONG>, <STRONG>noecho</STRONG>, <STRONG>nonl</STRONG>, <STRONG>noqiflush</STRONG>, <STRONG>noraw</STRONG>,
<STRONG>notimeout</STRONG>, <STRONG>qiflush</STRONG>, <STRONG>raw</STRONG>, <STRONG>timeout</STRONG>, <STRONG>wtimeout</STRONG>, <STRONG>typeahead</STRONG> - get and set
<EM>curses</EM> terminal input options
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></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>intrflush(WINDOW</STRONG> <STRONG>*</STRONG> <EM>win</EM> <EM>/*</EM> <EM>ignored</EM> <EM>*/</EM><STRONG>,</STRONG> <STRONG>bool</STRONG> <EM>bf</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>keypad(WINDOW</STRONG> <STRONG>*</STRONG> <EM>win</EM><STRONG>,</STRONG> <STRONG>bool</STRONG> <EM>bf</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>meta(WINDOW</STRONG> <STRONG>*</STRONG> <EM>win</EM> <EM>/*</EM> <EM>ignored</EM> <EM>*/</EM><STRONG>,</STRONG> <STRONG>bool</STRONG> <EM>bf</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>nodelay(WINDOW</STRONG> <STRONG>*</STRONG> <EM>win</EM><STRONG>,</STRONG> <STRONG>bool</STRONG> <EM>bf</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>notimeout(WINDOW</STRONG> <STRONG>*</STRONG> <EM>win</EM><STRONG>,</STRONG> <STRONG>bool</STRONG> <EM>bf</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>nl(void);</STRONG>
<STRONG>int</STRONG> <STRONG>nonl(void);</STRONG>
<STRONG>void</STRONG> <STRONG>qiflush(void);</STRONG>
<STRONG>void</STRONG> <STRONG>noqiflush(void);</STRONG>
<STRONG>int</STRONG> <STRONG>raw(void);</STRONG>
<STRONG>int</STRONG> <STRONG>noraw(void);</STRONG>
<STRONG>int</STRONG> <STRONG>halfdelay(int</STRONG> <EM>tenths</EM><STRONG>);</STRONG>
<STRONG>void</STRONG> <STRONG>timeout(int</STRONG> <EM>delay</EM><STRONG>);</STRONG>
<STRONG>void</STRONG> <STRONG>wtimeout(WINDOW</STRONG> <STRONG>*</STRONG> <EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>delay</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>typeahead(int</STRONG> <EM>fd</EM><STRONG>);</STRONG>
<EM>/*</EM> <EM>extensions</EM> <EM>*/</EM>
<STRONG>int</STRONG> <STRONG>is_cbreak(void);</STRONG>
<STRONG>int</STRONG> <STRONG>is_echo(void);</STRONG>
<STRONG>int</STRONG> <STRONG>is_nl(void);</STRONG>
<STRONG>int</STRONG> <STRONG>is_raw(void);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
<EM>curses</EM> offers configurable parameters permitting an application to
control the handling of input from the terminal. Some, such as those
affecting the terminal's <EM>mode</EM> or line discipline, are global, applying
to all windows; others apply only to a specific window. The library
does not automatically apply such parameters to new or derived windows;
an application must configure each window for the desired behavior.
Some descriptions below make reference to an <EM>input</EM> <EM>character</EM> <EM>reading</EM>
<EM>function</EM>: this is <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> in the non-wide character <EM>curses</EM> API and
<STRONG><A HREF="curs_get_wch.3x.html">wget_wch(3x)</A></STRONG> in the wide character API. In addition to the variant
forms of these described in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>, the <EM>curses</EM> functions
<STRONG><A HREF="curs_getstr.3x.html">wgetstr(3x)</A></STRONG> and <STRONG><A HREF="curs_get_wstr.3x.html">wget_wstr(3x)</A></STRONG> and their own variants call the
appropriate input character reading function.
</PRE><H3><a name="h3-cbreak_nocbreak">cbreak, nocbreak</a></H3><PRE>
Normally, the terminal driver buffers typed characters, not delivering
them to an application until a line feed or carriage return is typed.
This canonical ("cooked") line discipline also supports software flow
control, simple line editing functions (character and word erase, and
whole-line erasure or "kill"), and job control. <STRONG>cbreak</STRONG> configures the
terminal in <EM>cbreak</EM> <EM>mode</EM>, which disables line buffering and erase and
kill character processing -- the interrupt, quit, suspend, and flow
control characters are unaffected -- and makes characters typed by the
user immediately available to the program. <STRONG>nocbreak</STRONG> restores canonical
("cooked") mode.
The state of the terminal is unknown to a <EM>curses</EM> application when it
starts; therefore, a program should call <STRONG>cbreak</STRONG> or <STRONG>nocbreak</STRONG> explicitly.
Most interactive programs using <EM>curses</EM> set cbreak mode. Calling <STRONG>cbreak</STRONG>
overrides <STRONG>raw</STRONG>. The man page for the input character reading function
discusses how <STRONG>cbreak</STRONG> and <STRONG>nocbreak</STRONG> interact with <STRONG>echo</STRONG> and <STRONG>noecho</STRONG>.
</PRE><H3><a name="h3-echo_noecho">echo, noecho</a></H3><PRE>
<STRONG>echo</STRONG> and <STRONG>noecho</STRONG> determine whether characters typed by the user are
written to the <EM>curses</EM> window by the input character reading function as
they are typed. <EM>curses</EM> always disables the terminal driver's own
echoing. By default, a <EM>curses</EM> screen's echo option is set. 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 call
<STRONG>noecho</STRONG>. The man page for the input character reading function
discusses how <STRONG>echo</STRONG> and <STRONG>noecho</STRONG> interact with <STRONG>cbreak</STRONG> and <STRONG>nocbreak</STRONG>.
</PRE><H3><a name="h3-halfdelay">halfdelay</a></H3><PRE>
<STRONG>halfdelay</STRONG> configures <EM>half-delay</EM> <EM>mode</EM>, which is similar to cbreak mode
in that characters typed by the user are immediately available to the
program. However, after blocking for <EM>tenths</EM> tenth-seconds, an input
character reading function returns <STRONG>ERR</STRONG> if no input is pending. The
value of <EM>tenths</EM> must be between 1 and 255. Use <STRONG>nocbreak</STRONG> to leave half-
delay mode.
</PRE><H3><a name="h3-intrflush">intrflush</a></H3><PRE>
<STRONG>intrflush</STRONG> calls <STRONG>qiflush</STRONG> (see below) if <EM>bf</EM> is <STRONG>TRUE</STRONG>, and <STRONG>noqiflush</STRONG> if <EM>bf</EM>
is <STRONG>FALSE</STRONG>. It ignores its <EM>win</EM> argument.
</PRE><H3><a name="h3-keypad">keypad</a></H3><PRE>
<STRONG>keypad</STRONG> enables recognition of a terminal's function keys. If enabled
(<EM>bf</EM> is <STRONG>TRUE</STRONG>) then when an input character reading function reads ESC,
it waits for further input corresponding to an escape sequence defined
by the terminal type description. If a valid sequence populates the
input stream, the input character reading function returns a value
representing the function key, such as <STRONG>KEY_LEFT</STRONG>. (Wide-character API
users: <STRONG><A HREF="curs_get_wch.3x.html">wget_wch(3x)</A></STRONG> returns <STRONG>KEY_CODE_YES</STRONG> to indicate the availability
of a function key code in its <EM>wch</EM> parameter.) If the sequence is
invalid, the input character reading function returns only its last
character. If disabled (<EM>bf</EM> is <STRONG>FALSE</STRONG>), <EM>curses</EM> does not treat function
keys specially and the program has to interpret escape sequences
itself. If the terminal type description defines the <STRONG>keypad_local</STRONG>
(<STRONG>rmkx</STRONG>) and <STRONG>keypad_xmit</STRONG> (<STRONG>smkx</STRONG>) capabilities, enabling a window's keypad
mode sets the terminal's keypad to transmit, and disabling keypad mode
sets the terminal's keypad to work locally. By default, a window's
keypad mode is off.
</PRE><H3><a name="h3-meta">meta</a></H3><PRE>
Initially, whether the terminal returns 7- or 8-bit character codes on
input depends on the configuration of the terminal driver; on POSIX
systems, see <STRONG>termios(3)</STRONG>. To force 8 bits to be returned, call
<STRONG>meta(</STRONG>...<STRONG>,</STRONG> <STRONG>TRUE)</STRONG>; this is equivalent, on POSIX systems, to setting the
CS8 flag on the terminal. To force 7 bits to be returned, call
<STRONG>meta(</STRONG>...<STRONG>,</STRONG> <STRONG>FALSE)</STRONG>; this is equivalent, on POSIX systems, to setting the
CS7 flag on the terminal. <EM>curses</EM> ignores the window argument <EM>win</EM>. If
the <EM>terminfo</EM> string capabilities <STRONG>meta_on</STRONG> (<STRONG>smm</STRONG>) and <STRONG>meta_off</STRONG> (<STRONG>rmm</STRONG>) are
defined for the terminal type, enabling meta mode sends <STRONG>smm</STRONG>'s value to
the terminal and disabling it sends that of <STRONG>rmm</STRONG> to the terminal.
</PRE><H3><a name="h3-nl_nonl">nl, nonl</a></H3><PRE>
Initially, whether the terminal reports a carriage return using the
character code for a line feed in cbreak or raw modes depends on the
configuration of the terminal driver; see <STRONG>termios(3)</STRONG>. <STRONG>nl</STRONG> configures
the terminal to perform this translation. <STRONG>nonl</STRONG> disables it. Under its
canonical ("cooked") line discipline, the terminal driver always
translates carriage returns to line feeds.
</PRE><H3><a name="h3-nodelay">nodelay</a></H3><PRE>
<STRONG>nodelay</STRONG> configures the input character reading function to be non-
blocking for window <EM>win</EM>. If no input is ready, the reading function
returns <STRONG>ERR</STRONG>. If disabled (<EM>bf</EM> is <STRONG>FALSE</STRONG>), the reading function does not
return until it has input.
</PRE><H3><a name="h3-notimeout">notimeout</a></H3><PRE>
When <STRONG>keypad</STRONG> has been called on a window and the input character reading
function reads an ESC character from it, <EM>curses</EM> sets a timer while
waiting for the next character. If the timer elapses, <EM>curses</EM>
interprets the ESC as an explicit press of the terminal's Escape key
(or equivalent). <STRONG>notimeout(</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>TRUE)</STRONG> disables this timer. The
purpose of the timeout is to distinguish sequences produced by a
function key from those typed by a user. If this timer is disabled,
<EM>curses</EM> waits forever for subsequent keystrokes until it determines the
escape sequence to be valid or invalid.
</PRE><H3><a name="h3-qiflush_noqiflush">qiflush, noqiflush</a></H3><PRE>
<STRONG>qiflush</STRONG> and <STRONG>noqiflush</STRONG> configure the terminal driver's treatment of its
input and output queues when it handles the interrupt, suspend, or quit
characters under the canonical ("cooked") or cbreak line disciplines on
POSIX systems; see <STRONG>termios(3)</STRONG>. The default behavior is inherited from
the terminal driver settings. Calling <STRONG>qiflush</STRONG> configures the terminal
to <EM>flush</EM> the queues (discarding their contents) when any of these
events occurs, giving the impression of faster response to user input,
but making the library's model of the screen contents incorrect.
Calling <STRONG>noqiflush</STRONG> prevents such flushing, but might frustrate impatient
users on slow connections if a <EM>curses</EM> update of the screen is in
progress when the event occurs; see <STRONG>typeahead</STRONG> below for a mitigation of
this problem. You may want to call <STRONG>noqiflush</STRONG> in a signal handler if,
after the handler exits, you want output to continue as though the
signal had not occurred.
</PRE><H3><a name="h3-raw_noraw">raw, noraw</a></H3><PRE>
<STRONG>raw</STRONG> configures the terminal to read input in <EM>raw</EM> <EM>mode</EM>, which is similar
to cbreak mode (see <STRONG>cbreak</STRONG> above) except that it furthermore passes
through the terminal's configured interrupt, quit, suspend, and flow
control characters uninterpreted to the application, instead of
generating a signal or acting on I/O flow. The behavior of the
terminal's "Break" key (if any) depends on terminal driver
configuration parameters that <EM>curses</EM> does not handle. <STRONG>noraw</STRONG> restores
the terminal's canonical ("cooked") line discipline.
</PRE><H3><a name="h3-timeout_wtimeout">timeout, wtimeout</a></H3><PRE>
<STRONG>wtimeout</STRONG> configures whether a <EM>curses</EM> input character reading function
called on window <EM>win</EM> uses blocking or non-blocking reads. If <EM>delay</EM> is
negative, <EM>curses</EM> uses a blocking read, waiting indefinitely for input.
If <EM>delay</EM> is zero, the read is non-blocking; an input character reading
function returns <STRONG>ERR</STRONG> if no input is pending. If <EM>delay</EM> is positive, an
input character reading function blocks for <EM>delay</EM> milliseconds, and
returns <STRONG>ERR</STRONG> if the delay elapses and there is still no input pending.
<STRONG>timeout</STRONG> calls <STRONG>wtimeout</STRONG> on <STRONG>stdscr</STRONG>.
</PRE><H3><a name="h3-typeahead">typeahead</a></H3><PRE>
Normally, a <EM>curses</EM> library checks the terminal's input file descriptor
for activity with <STRONG>poll(2)</STRONG> or <STRONG>select(2)</STRONG> while updating the screen; if it
finds any, it postpones output until the next <STRONG><A HREF="curs_refresh.3x.html">wrefresh(3x)</A></STRONG> or
<STRONG><A HREF="curs_refresh.3x.html">doupdate(3x)</A></STRONG> call, allowing faster response to user key strokes. The
library tests the file descriptor corresponding to the <EM>FILE</EM> stream
pointer passed to <STRONG><A HREF="curs_initscr.3x.html">newterm(3x)</A></STRONG> (or <EM>stdin</EM> if <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG> was called), for
pending input. <STRONG>typeahead</STRONG> instructs <EM>curses</EM> to test file descriptor <EM>fd</EM>
instead. An <EM>fd</EM> of <STRONG>-1</STRONG> disables the check.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
<STRONG>timeout</STRONG> and <STRONG>wtimeout</STRONG> return no value.
<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>nl</STRONG>, <STRONG>nonl</STRONG>, <STRONG>raw</STRONG>, <STRONG>noraw</STRONG>, and <STRONG>typeahead</STRONG> return <STRONG>OK</STRONG> on
success and <STRONG>ERR</STRONG> on failure.
In <EM>ncurses</EM>, the functions in the previous paragraph return <STRONG>ERR</STRONG> if
<STRONG>o</STRONG> the library's <EM>TERMINAL</EM> structure for the device has not been
initialized with <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">newterm(3x)</A></STRONG>, or <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG>, or
<STRONG>o</STRONG> <EM>win</EM> is a null pointer (except with <STRONG>intrflush</STRONG> and <STRONG>meta</STRONG>, which ignore
its value).
Further, <STRONG>halfdelay</STRONG> returns <STRONG>ERR</STRONG> if <EM>delay</EM> is outside the range 1..255.
See section "EXTENSIONS" below for the return values of <STRONG>is_cbreak</STRONG>,
<STRONG>is_echo</STRONG>, <STRONG>is_nl</STRONG>, and <STRONG>is_raw</STRONG>.
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
<STRONG>echo</STRONG>, <STRONG>noecho</STRONG>, <STRONG>halfdelay</STRONG>, <STRONG>intrflush</STRONG>, <STRONG>meta</STRONG>, <STRONG>nl</STRONG>, <STRONG>nonl</STRONG>, <STRONG>nodelay</STRONG>, <STRONG>notimeout</STRONG>,
<STRONG>noqiflush</STRONG>, <STRONG>qiflush</STRONG>, <STRONG>timeout</STRONG>, and <STRONG>wtimeout</STRONG> may be implemented as macros.
<STRONG>noraw</STRONG> and <STRONG>nocbreak</STRONG> follow historical practice in that they attempt to
restore the terminal's canonical ("cooked") line discipline from raw
and cbreak, respectively. Mixing <STRONG>raw</STRONG>/<STRONG>noraw</STRONG> calls with <STRONG>cbreak</STRONG>/<STRONG>nocbreak</STRONG>
calls leads to terminal driver control states that are hard to predict
or understand; doing so is not recommended.
<EM>curses</EM> documentation uses the terms "delay" and "timeout" freely to
describe two related but distinct aspects of input handling, at the
risk of confusing the user. The functions <STRONG>halfdelay</STRONG>, <STRONG>nodelay</STRONG>, <STRONG>timeout</STRONG>,
and <STRONG>wtimeout</STRONG> configure whether the input character reading function
(<STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> or <STRONG><A HREF="curs_get_wch.3x.html">wget_wch(3x)</A></STRONG>) waits for keyboard input to begin, and for
how long. <STRONG>keypad</STRONG> configures whether that function waits for further
input if the first character it reads is ESC. Calling <STRONG>notimeout</STRONG>, which
has nothing to do with <STRONG>timeout</STRONG> or <STRONG>wtimeout</STRONG>, makes this delay in
expectation of further characters effectively infinite. X/Open Curses
affords no means of otherwise configuring the length of this second
delay, but an AIX and <EM>ncurses</EM> extension, <STRONG>ESCDELAY</STRONG>, is available both as
an environment variable and a global symbol permitting the user and
application, respectively, to do so; see <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG> and
<STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>.
</PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
<EM>ncurses</EM> provides four "is_" functions corresponding to <STRONG>cbreak</STRONG>, <STRONG>echo</STRONG>,
<STRONG>nl</STRONG>, and <STRONG>raw</STRONG>, permitting their states to be queried by the application.
<STRONG>Query</STRONG> <STRONG>Set</STRONG> <STRONG>Reset</STRONG>
------------------------------
is_cbreak cbreak nocbreak
is_echo echo noecho
is_nl nl nonl
is_raw raw noraw
In each case, the function returns
<STRONG>1</STRONG> if the option is set,
<STRONG>0</STRONG> if the option is unset, or
<STRONG>-1</STRONG> if the library's <EM>TERMINAL</EM> structure for the device has not been
initialized.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
Applications employing <EM>ncurses</EM> extensions should condition their use on
the visibility of the <STRONG>NCURSES_VERSION</STRONG> preprocessor macro.
Except as noted in section "EXTENSIONS" above, X/Open Curses Issue 4
describes these functions. It specifies no error conditions for them.
SVr4 describes a successful return value only as "an integer value
other than <EM>ERR</EM>".
<EM>ncurses</EM> follows X/Open Curses and the historical practice of System V
<EM>curses</EM>, clearing the terminal driver's "echo" flag when initializing
the screen. BSD <EM>curses</EM> did not, but its <EM>raw</EM> function turned it off as
a side effect. For best portability, call <EM>echo</EM> or <EM>noecho</EM> explicitly
just after initialization, even if your program retains the terminal's
canonical ("cooked") line discipline.
X/Open Curses is ambiguous regarding whether <EM>raw</EM> should disable the
carriage return and line feed translation feature controlled by <EM>nl</EM> and
<EM>nonl</EM>. BSD <EM>curses</EM> turned off these translations; System V <EM>curses</EM> did
not. <EM>ncurses</EM> does so, on the assumption that a programmer requesting
raw input wants a clean (ideally, 8-bit clean) connection that the
operating system will not alter.
When <STRONG>keypad</STRONG> is first enabled for a window, <EM>ncurses</EM> loads the standard
function key string capabilities for the terminal type description of
its screen; see the entries beginning with "key_" in <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>. If
that description includes extended string capabilities, produced by the
<STRONG>-x</STRONG> option of <STRONG><A HREF="tic.1m.html">tic(1)</A></STRONG>, for example, then <EM>ncurses</EM> also defines keys for
the capabilities whose codes begin with "k". <EM>ncurses</EM> generates a
numeric key code for each such extended capability; depending on
previous loads of terminal type descriptions, these may differ from one
execution of a program to the next. <STRONG><A HREF="curs_util.3x.html">keyname(3x)</A></STRONG> recognizes the
generated key codes and returns a name beginning with "k" denoting the
<EM>terminfo</EM> capability name rather than "KEY_", used for <EM>curses</EM> key names.
On the other hand, an application can use <STRONG><A HREF="define_key.3x.html">define_key(3x)</A></STRONG> to bind a
selected key to a string of the programmer's choice. This feature
enables an application to check for its presence with <STRONG><A HREF="curs_terminfo.3x.html">tigetstr(3x)</A></STRONG>, and
reassign the numeric key code to match its own needs.
Low-level applications can use <STRONG><A HREF="curs_terminfo.3x.html">tigetstr(3x)</A></STRONG> to obtain the definition of
any string capability. <EM>curses</EM> applications use the input character
reading function to obtain key codes from input and rely upon the order
in which the string capabilities are loaded. Multiple key capability
strings can have the same value, but the input character reading
function can report only one key code. Most <EM>curses</EM> implementations
(including <EM>ncurses</EM>) load key definitions in the order they appear in
the <STRONG>strfnames</STRONG> array of string capability names; see <STRONG><A HREF="term_variables.3x.html">term_variables(3x)</A></STRONG>.
The last capability read using a particular definition determines the
key code to be reported. In <EM>ncurses</EM>, extended capabilities can be
interpreted as key definitions. The library loads these after its
built-in definitions, and if an extended capability's value is the same
as one previously loaded, the library uses the later definition.
</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
4BSD (1980) introduced <EM>echo</EM>, <EM>noecho</EM>, <EM>nl</EM>, <EM>nonl</EM>, <EM>raw</EM>, and <EM>noraw</EM>.
SVr2 (1984) featured a new terminal driver, extending the <EM>curses</EM> API to
support it with <EM>cbreak</EM>, <EM>nocbreak</EM>, <EM>intrflush</EM>, <EM>keypad</EM>, <EM>meta</EM>, <EM>nodelay</EM>, and
<EM>typeahead</EM>.
SVr3 (1987) added <EM>halfdelay</EM>, <EM>notimeout</EM>, and <EM>wtimeout</EM>. <EM>qiflush</EM> and
<EM>noqiflush</EM> appeared in SVr3.1 (1987), at which point <EM>intrflush</EM> became a
wrapper for either of these functions, depending on the value of its
Boolean argument. SVr3.1 also added <EM>timeout</EM>.
<EM>ncurses</EM> 6.5 (2024) introduced <EM>is</EM><STRONG>_</STRONG><EM>cbreak</EM>, <EM>is</EM><STRONG>_</STRONG><EM>echo</EM>, <EM>is</EM><STRONG>_</STRONG><EM>nl</EM>, and <EM>is</EM><STRONG>_</STRONG><EM>raw</EM>.
Formerly, <EM>ncurses</EM> used <EM>nl</EM> and <EM>nonl</EM> to control the conversion of
newlines to carriage return/line feed on output as well as input.
X/Open Curses documents the use of these functions only for input.
This difference arose from converting the <EM>pcurses</EM> source (1986), which
used <STRONG>ioctl(2)</STRONG> calls and the <EM>sgttyb</EM> structure, to <EM>termios</EM> (the POSIX
terminal API). In the former, both input and output conversions were
controlled via a single option "CRMOD", while the latter separates
these features. Because that conversion interferes with output
optimization, <EM>ncurses</EM> 6.2 (2020) amended <EM>nl</EM> and <EM>nonl</EM> to eliminate their
effect on output.
</PRE><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>termios(3)</STRONG>, <STRONG><A HREF="term_variables.3x.html">term_variables(3x)</A></STRONG>
ncurses 6.6 2025-10-04 <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-cbreak_nocbreak">cbreak, nocbreak</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-nl_nonl">nl, nonl</a></li>
<li><a href="#h3-nodelay">nodelay</a></li>
<li><a href="#h3-notimeout">notimeout</a></li>
<li><a href="#h3-qiflush_noqiflush">qiflush, noqiflush</a></li>
<li><a href="#h3-raw_noraw">raw, noraw</a></li>
<li><a href="#h3-timeout_wtimeout">timeout, wtimeout</a></li>
<li><a href="#h3-typeahead">typeahead</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-HISTORY">HISTORY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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