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-<H1 class="no-header">curs_inopts 3x</H1>
+<H1 class="no-header">curs_inopts 3x 2024-05-25 ncurses 6.5 Library calls</H1>
<PRE>
-<STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>
<STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>
+<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>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
- options
+ <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>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>intrflush(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>bool</STRONG> <STRONG>bf);</STRONG>
- <STRONG>int</STRONG> <STRONG>keypad(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>bool</STRONG> <STRONG>bf);</STRONG>
- <STRONG>int</STRONG> <STRONG>meta(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>bool</STRONG> <STRONG>bf);</STRONG>
- <STRONG>int</STRONG> <STRONG>nodelay(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>bool</STRONG> <STRONG>bf);</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>void</STRONG> <STRONG>noqiflush(void);</STRONG>
- <STRONG>void</STRONG> <STRONG>qiflush(void);</STRONG>
- <STRONG>int</STRONG> <STRONG>notimeout(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>bool</STRONG> <STRONG>bf);</STRONG>
- <STRONG>void</STRONG> <STRONG>timeout(int</STRONG> <STRONG>delay);</STRONG>
- <STRONG>void</STRONG> <STRONG>wtimeout(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>delay);</STRONG>
- <STRONG>int</STRONG> <STRONG>typeahead(int</STRONG> <STRONG>fd);</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>
- The <STRONG>ncurses</STRONG> library provides several functions which let
- an application change the way input from the terminal is
- handled. Some are global, applying to all windows. Oth-
- ers apply only to a specific window. Window-specific set-
- tings are not automatically applied to new or derived win-
- dows. An application must apply these to each window, if
- the same behavior is needed.
-
-
-</PRE><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>.]
-
-
-</PRE><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>.]
+ <EM>curses</EM> offers configurable parameters permitting an application to
+ control the handling of input from the terminal. Some 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.
+ <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> returns the terminal to normal ("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> window has its echo flag 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>
- 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 <EM>tenths</EM>
- must be a number between 1 and 255. Use <STRONG>nocbreak</STRONG> to leave
+ <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> tenths of 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>
- If the <STRONG>intrflush</STRONG> option is enabled (<EM>bf</EM> is <STRONG>TRUE</STRONG>), 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 in-
- terrupt, but causing <STRONG>curses</STRONG> to have the wrong idea of what
- is on the screen. Disabling the option (<EM>bf</EM> is <STRONG>FALSE</STRONG>) pre-
- vents the flush. The default for the option is inherited
- from the tty driver settings. The window argument is ig-
- nored.
+ <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>
- 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
- keypad is <STRONG>FALSE</STRONG>.
+ <STRONG>keypad</STRONG> enables recognition of a terminal's function keys. If enabled
+ (<EM>bf</EM> is <STRONG>TRUE</STRONG>), 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 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's keypad can
+ be turned on (made to transmit) and off (made to work locally), <STRONG>keypad</STRONG>
+ configures it consistently with the <EM>bf</EM> parameter. 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 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.
+ Initially, whether the terminal returns 7- or 8-bit character codes on
+ input depends on the configuration of the terminal driver; 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. The window argument, <EM>win</EM>, is always ignored. If the <EM>term-</EM>
+ <EM>info</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> to the terminal and
+ disabling it sends <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 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.
</PRE><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.
-
-
-</PRE><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>.
-
-
-</PRE><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.
-
-
-</PRE><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).
+ <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 the input character reading function reads an ESC character, it
+ sets a timer while waiting for the next character. <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. To configure the timeout rather than disabling it, see <STRONG>wtimeout</STRONG>
+ below.
+
+
+</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 in <EM>cbreak</EM> and "cooked" modes; 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 flush the queues
+ 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 you want output to continue after the handler exits
+ as though the interrupt 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> exits raw
+ mode.
+
+
+</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, a blocking read is used, waiting indefinitely for input. If
+ <EM>delay</EM> is zero, a non-blocking read is used; 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>
- 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.
+ Normally, a <EM>curses</EM> library checks the terminal for input while updating
+ the screen. If any is found, the update is postponed 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>
- 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.
+ <STRONG>timeout</STRONG> and <STRONG>wtimeout</STRONG> return no value.
- 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,
+ <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.
- <STRONG>halfdelay</STRONG>
- returns an error if its parameter is outside
- the range 1..255.
+ In <EM>ncurses</EM>, the functions in the previous paragraph return <STRONG>ERR</STRONG> if
+ <STRONG>o</STRONG> the terminal is not initialized or
-</PRE><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&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
- used.
+ <STRONG>o</STRONG> <EM>win</EM> is <STRONG>NULL</STRONG> (except for <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>
- 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.
+ <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 normal ("cooked") mode from raw and cbreak modes, 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.
+
+
+</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
- 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
- recommended.
+ <STRONG>1</STRONG> if the flag is set,
+
+ <STRONG>0</STRONG> if the flag is reset, or
+
+ <STRONG>-1</STRONG> if the library is not 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 <EM>curses</EM> describes a successful return value only as "an integer
+ value other than <STRONG>ERR</STRONG>".
+
+ <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 <STRONG>echo</STRONG> or <STRONG>noecho</STRONG> explicitly
+ just after initialization, even if your program remains in normal
+ ("cooked") mode.
+
+ 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> did turn 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, <EM>ncurses</EM> loads the key definitions for the
+ current terminal description. If the terminal description includes
+ extended string capabilities, for example, by using the <STRONG>-x</STRONG> option of
+ <STRONG><A HREF="tic.1m.html">tic(1)</A></STRONG>, then <EM>ncurses</EM> also defines keys for the capabilities whose names
+ begin with "k". Corresponding key codes 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 <STRONG><A HREF="curs_util.3x.html">keyname(3x)</A></STRONG> function (which then returns a name
+ beginning with "k" denoting the <EM>terminfo</EM> capability name rather than
+ "K", 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 specific key to a string of the
+ programmer's choice. This feature enables an application to check for
+ an extended capability's presence with <STRONG><A HREF="curs_terminfo.3x.html">tigetstr(3x)</A></STRONG>, and reassign the
+ keycode 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. 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.
+
+
+</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
+ 4BSD <EM>curses</EM> (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 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>termio(7)</STRONG>
+ <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><A HREF="term_variables.3x.html">term_variables(3x)</A></STRONG>, <STRONG>termios(3)</STRONG>
-
<STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>
+
ncurses 6.5 2024-05-25 <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
-<li><a href="#h3-cbreak">cbreak</a></li>
-<li><a href="#h3-echo_noecho">echo/noecho</a></li>
+<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-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-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-PORTABILITY">PORTABILITY</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>
projects / ncurses.git / blobdiff