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- * @Id: curs_getch.3x,v 1.68 2023/08/19 20:45:12 tom Exp @
+ * @Id: curs_getch.3x,v 1.72 2023/09/16 23:34:43 tom Exp @
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-<H1 class="no-header">curs_getch 3x 2023-08-19 ncurses 6.4 Library calls</H1>
+<H1 class="no-header">curs_getch 3x 2023-09-16 ncurses 6.4 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, <STRONG>mvwgetch</STRONG>, <STRONG>ungetch</STRONG>, <STRONG>has_key</STRONG> - get (or push back)
- characters from <STRONG>curses</STRONG> terminal keyboard
+ characters from <EM>curses</EM> terminal keyboard
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
returned. In delay mode, the program waits until the system passes
text through to the program. Depending on the setting of <STRONG>cbreak</STRONG>, this
is after one character (cbreak mode), or after the first newline
- (nocbreak mode). In half-delay mode, the program waits until a charac-
- ter is typed or the specified timeout has been reached.
+ (nocbreak mode). In half-delay mode, the program waits until a
+ character is typed or the specified timeout has been reached.
If <STRONG>echo</STRONG> is enabled, and the window is not a pad, then the character
- will also be echoed into the designated window according to the follow-
- ing rules:
+ will also be echoed into the designated window according to the
+ following rules:
<STRONG>o</STRONG> If the character is the current erase character, left arrow, or
backspace, the cursor is moved one space to the left and that
screen position is erased as if <STRONG>delch</STRONG> had been called.
- <STRONG>o</STRONG> If the character value is any other <STRONG>KEY_</STRONG> define, the user is alert-
- ed with a <STRONG>beep</STRONG> call.
+ <STRONG>o</STRONG> If the character value is any other <STRONG>KEY_</STRONG> define, the user is
+ alerted with a <STRONG>beep</STRONG> call.
<STRONG>o</STRONG> If the character is a carriage-return, and if <STRONG>nl</STRONG> is enabled, it is
translated to a line-feed after echoing.
function key is returned instead of the raw characters:
<STRONG>o</STRONG> The predefined function keys are listed in <STRONG><curses.h></STRONG> as macros
- with values outside the range of 8-bit characters. Their names be-
- gin with <STRONG>KEY_</STRONG>.
+ with values outside the range of 8-bit characters. Their names
+ begin with <STRONG>KEY_</STRONG>.
- <STRONG>o</STRONG> Other (user-defined) function keys which may be defined using <STRONG>de-</STRONG>
- <STRONG><A HREF="define_key.3x.html">fine_key(3x)</A></STRONG> have no names, but also are expected to have values
+ <STRONG>o</STRONG> Other (user-defined) function keys which may be defined using
+ <STRONG><A HREF="define_key.3x.html">define_key(3x)</A></STRONG> have no names, but also are expected to have values
outside the range of 8-bit characters.
Thus, a variable intended to hold the return value of a function key
must be of short size or larger.
- When a character that could be the beginning of a function key is re-
- ceived (which, on modern terminals, means an escape character), <STRONG>curses</STRONG>
- sets a timer. If the remainder of the sequence does not come in within
- the designated time, the character is passed through; otherwise, the
- function key value is returned. For this reason, many terminals expe-
- rience a delay between the time a user presses the escape key and the
- escape is returned to the program.
+ When a character that could be the beginning of a function key is
+ received (which, on modern terminals, means an escape character),
+ <STRONG>curses</STRONG> sets a timer. If the remainder of the sequence does not come in
+ within the designated time, the character is passed through; otherwise,
+ the function key value is returned. For this reason, many terminals
+ experience a delay between the time a user presses the escape key and
+ the escape is returned to the program.
In <STRONG>ncurses</STRONG>, the timer normally expires after the value in <STRONG>ESCDELAY</STRONG> (see
<STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>). If <STRONG>notimeout</STRONG> is <STRONG>TRUE</STRONG>, the timer does not expire;
it is an infinite (or very large) value. Because function keys usually
- begin with an escape character, the terminal may appear to hang in no-
- timeout mode after pressing the escape key until another key is
+ begin with an escape character, the terminal may appear to hang in
+ notimeout mode after pressing the escape key until another key is
pressed.
</PRE><H3><a name="h3-Ungetting-characters">Ungetting characters</a></H3><PRE>
The <STRONG>ungetch</STRONG> routine places <EM>ch</EM> back onto the input queue to be returned
- by the next call to <STRONG>wgetch</STRONG>. There is just one input queue for all win-
- dows.
+ by the next call to <STRONG>wgetch</STRONG>. There is just one input queue for all
+ windows.
</PRE><H3><a name="h3-Predefined-key-codes">Predefined key-codes</a></H3><PRE>
<STRONG>o</STRONG> Except for the special case <STRONG>KEY_RESIZE</STRONG>, it is necessary to enable
<STRONG>keypad</STRONG> for <STRONG>getch</STRONG> to return these codes.
- <STRONG>o</STRONG> Not all of these are necessarily supported on any particular termi-
- nal.
+ <STRONG>o</STRONG> Not all of these are necessarily supported on any particular
+ terminal.
- <STRONG>o</STRONG> The naming convention may seem obscure, with some apparent mis-
- spellings (such as "RSUME" for "resume"). The names correspond to
- the long terminfo capability names for the keys, and were defined
- long ago, in the 1980s.
+ <STRONG>o</STRONG> The naming convention may seem obscure, with some apparent
+ misspellings (such as "RSUME" for "resume"). The names correspond
+ to the long terminfo capability names for the keys, and were
+ defined long ago, in the 1980s.
<STRONG>Name</STRONG> <STRONG>Key</STRONG> <STRONG>name</STRONG>
-------------------------------------------------
whether or not <STRONG>keypad</STRONG> has been enabled.
<STRONG>o</STRONG> <STRONG>KEY_MOUSE</STRONG> is returned for mouse-events (see <STRONG><A HREF="curs_mouse.3x.html">curs_mouse(3x)</A></STRONG>). This
- code relies upon whether or not <STRONG><A HREF="curs_inopts.3x.html">keypad(3x)</A></STRONG> has been enabled, be-
- cause (e.g., with <STRONG>xterm(1)</STRONG> mouse prototocol) ncurses must read es-
- cape sequences, just like a function key.
+ code relies upon whether or not <STRONG><A HREF="curs_inopts.3x.html">keypad(3x)</A></STRONG> has been enabled,
+ because (e.g., with <STRONG>xterm(1)</STRONG> mouse prototocol) ncurses must read
+ escape sequences, just like a function key.
</PRE><H3><a name="h3-Testing-key-codes">Testing key-codes</a></H3><PRE>
- The <STRONG>has_key</STRONG> routine takes a key-code value from the above list, and re-
- turns <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG> according to whether the current terminal type rec-
- ognizes a key with that value.
+ The <STRONG>has_key</STRONG> routine takes a key-code value from the above list, and
+ returns <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG> according to whether the current terminal type
+ recognizes a key with that value.
The library also supports these extensions:
<STRONG>wgetch</STRONG>
returns <STRONG>ERR</STRONG> if the window pointer is null, or if its timeout
- expires without having any data, or if the execution was inter-
- rupted by a signal (<STRONG>errno</STRONG> will be set to <STRONG>EINTR</STRONG>).
+ expires without having any data, or if the execution was
+ interrupted by a signal (<STRONG>errno</STRONG> will be set to <STRONG>EINTR</STRONG>).
Functions with a "mv" prefix first perform a cursor movement using
<STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
is discouraged, as it will cause a delay of up to one second while the
keypad code looks for a following function-key sequence.
- Some keys may be the same as commonly used control keys, e.g., <STRONG>KEY_EN-</STRONG>
- <STRONG>TER</STRONG> versus control/M, <STRONG>KEY_BACKSPACE</STRONG> versus control/H. Some curses im-
- plementations may differ according to whether they treat these control
- keys specially (and ignore the terminfo), or use the terminfo defini-
- tions. <STRONG>Ncurses</STRONG> uses the terminfo definition. If it says that <STRONG>KEY_EN-</STRONG>
- <STRONG>TER</STRONG> is control/M, <STRONG>getch</STRONG> will return <STRONG>KEY_ENTER</STRONG> when you press control/M.
+ Some keys may be the same as commonly used control keys, e.g.,
+ <STRONG>KEY_ENTER</STRONG> versus control/M, <STRONG>KEY_BACKSPACE</STRONG> versus control/H. Some
+ curses implementations may differ according to whether they treat these
+ control keys specially (and ignore the terminfo), or use the terminfo
+ definitions. <STRONG>Ncurses</STRONG> uses the terminfo definition. If it says that
+ <STRONG>KEY_ENTER</STRONG> is control/M, <STRONG>getch</STRONG> will return <STRONG>KEY_ENTER</STRONG> when you press
+ control/M.
- Generally, <STRONG>KEY_ENTER</STRONG> denotes the character(s) sent by the <EM>Enter</EM> key on
+ Generally, <STRONG>KEY_ENTER</STRONG> denotes the character(s) sent by the <EM>Enter</EM> key on
the numeric keypad:
<STRONG>o</STRONG> the terminal description lists the most useful keys,
- <STRONG>o</STRONG> the <EM>Enter</EM> key on the regular keyboard is already handled by the
+ <STRONG>o</STRONG> the <EM>Enter</EM> key on the regular keyboard is already handled by the
standard ASCII characters for carriage-return and line-feed,
<STRONG>o</STRONG> depending on whether <STRONG>nl</STRONG> or <STRONG>nonl</STRONG> was called, pressing "Enter" on the
- regular keyboard may return either a carriage-return or line-feed,
+ regular keyboard may return either a carriage-return or line-feed,
and finally
<STRONG>o</STRONG> "Enter or send" is the standard description for this key.
- When using <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, or <STRONG>mvwgetch</STRONG>, nocbreak mode
- (<STRONG>nocbreak</STRONG>) and echo mode (<STRONG>echo</STRONG>) should not be used at the same time.
- Depending on the state of the tty driver when each character is typed,
+ When using <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, or <STRONG>mvwgetch</STRONG>, nocbreak mode
+ (<STRONG>nocbreak</STRONG>) and echo mode (<STRONG>echo</STRONG>) should not be used at the same time.
+ Depending on the state of the tty driver when each character is typed,
the program may produce undesirable results.
Note that <STRONG>getch</STRONG>, <STRONG>mvgetch</STRONG>, and <STRONG>mvwgetch</STRONG> may be macros.
- Historically, the set of keypad macros was largely defined by the ex-
- tremely function-key-rich keyboard of the AT&T 7300, aka 3B1, aka Sa-
- fari 4. Modern personal computers usually have only a small subset of
- these. IBM PC-style consoles typically support little more than
- <STRONG>KEY_UP</STRONG>, <STRONG>KEY_DOWN</STRONG>, <STRONG>KEY_LEFT</STRONG>, <STRONG>KEY_RIGHT</STRONG>, <STRONG>KEY_HOME</STRONG>, <STRONG>KEY_END</STRONG>, <STRONG>KEY_NPAGE</STRONG>,
- <STRONG>KEY_PPAGE</STRONG>, and function keys 1 through 12. The Ins key is usually
+ Historically, the set of keypad macros was largely defined by the
+ extremely function-key-rich keyboard of the AT&T 7300, aka 3B1, aka
+ Safari 4. Modern personal computers usually have only a small subset
+ of these. IBM PC-style consoles typically support little more than
+ <STRONG>KEY_UP</STRONG>, <STRONG>KEY_DOWN</STRONG>, <STRONG>KEY_LEFT</STRONG>, <STRONG>KEY_RIGHT</STRONG>, <STRONG>KEY_HOME</STRONG>, <STRONG>KEY_END</STRONG>, <STRONG>KEY_NPAGE</STRONG>,
+ <STRONG>KEY_PPAGE</STRONG>, and function keys 1 through 12. The Ins key is usually
mapped to <STRONG>KEY_IC</STRONG>.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- The *get* functions are described in the XSI Curses standard, Issue 4.
- They read single-byte characters only. The standard specifies that
+ The *get* functions are described in the XSI Curses standard, Issue 4.
+ They read single-byte characters only. The standard specifies that
they return <STRONG>ERR</STRONG> on failure, but specifies no error conditions.
- The echo behavior of these functions on input of <STRONG>KEY_</STRONG> or backspace
- characters was not specified in the SVr4 documentation. This descrip-
- tion is adopted from the XSI Curses standard.
+ The echo behavior of these functions on input of <STRONG>KEY_</STRONG> or backspace
+ characters was not specified in the SVr4 documentation. This
+ description is adopted from the XSI Curses standard.
The behavior of <STRONG>getch</STRONG> and friends in the presence of handled signals is
unspecified in the SVr4 and XSI Curses documentation. Under historical
- curses implementations, it varied depending on whether the operating
- system's implementation of handled signal receipt interrupts a <STRONG>read(2)</STRONG>
- call in progress or not, and also (in some implementations) depending
+ curses implementations, it varied depending on whether the operating
+ system's implementation of handled signal receipt interrupts a <STRONG>read(2)</STRONG>
+ call in progress or not, and also (in some implementations) depending
on whether an input timeout or non-blocking mode has been set.
<STRONG>KEY_MOUSE</STRONG> is mentioned in XSI Curses, along with a few related terminfo
- capabilities, but no higher-level functions use the feature. The im-
- plementation in ncurses is an extension.
+ capabilities, but no higher-level functions use the feature. The
+ implementation in ncurses is an extension.
- <STRONG>KEY_RESIZE</STRONG> is an extension first implemented for ncurses. NetBSD curs-
- es later added this extension.
+ <STRONG>KEY_RESIZE</STRONG> is an extension first implemented for ncurses. NetBSD
+ curses later added this extension.
- Programmers concerned about portability should be prepared for either
- of two cases: (a) signal receipt does not interrupt <STRONG>getch</STRONG>; (b) signal
- receipt interrupts <STRONG>getch</STRONG> and causes it to return <STRONG>ERR</STRONG> with <STRONG>errno</STRONG> set to
+ Programmers concerned about portability should be prepared for either
+ of two cases: (a) signal receipt does not interrupt <STRONG>getch</STRONG>; (b) signal
+ receipt interrupts <STRONG>getch</STRONG> and causes it to return <STRONG>ERR</STRONG> with <STRONG>errno</STRONG> set to
<STRONG>EINTR</STRONG>.
- The <STRONG>has_key</STRONG> function is unique to <STRONG>ncurses</STRONG>. We recommend that any code
+ The <STRONG>has_key</STRONG> function is unique to <STRONG>ncurses</STRONG>. We recommend that any code
using it be conditionalized on the <STRONG>NCURSES_VERSION</STRONG> feature macro.
</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_inopts.3x.html">curs_inopts(3x)</A></STRONG>, <STRONG><A HREF="curs_mouse.3x.html">curs_mouse(3x)</A></STRONG>, <STRONG><A HREF="curs_move.3x.html">curs_move(3x)</A></STRONG>, <STRONG>curs_out-</STRONG>
- <STRONG><A HREF="curs_outopts.3x.html">opts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>.
+ <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>, <STRONG><A HREF="curs_mouse.3x.html">curs_mouse(3x)</A></STRONG>, <STRONG><A HREF="curs_move.3x.html">curs_move(3x)</A></STRONG>,
+ <STRONG><A HREF="curs_outopts.3x.html">
curs_outopts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>.
- Comparable functions in the wide-character (ncursesw) library are de-
- scribed in <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>.
+ Comparable functions in the wide-character (ncursesw) library are
+
described in <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>.
-ncurses 6.4 2023-0
8-19 <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>
+ncurses 6.4 2023-0
9-16 <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>
</PRE>
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