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- * @Id: curs_getch.3x,v 1.42 2015/07/21 08:44:04 tom Exp @
+ * @Id: curs_getch.3x,v 1.49 2016/10/15 16:44:01 tom Exp @
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-</PRE>
-<H2><a name="h2-NAME">NAME</a></H2><PRE>
+</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
-</PRE>
-<H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
+</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>int</STRONG> <STRONG>getch(void);</STRONG>
<STRONG>int</STRONG> <STRONG>has_key(int</STRONG> <EM>ch</EM><STRONG>);</STRONG>
-</PRE>
-<H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
+</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
-</PRE>
-<H3><a name="h3-Reading-characters">Reading characters</a></H3><PRE>
+</PRE><H3><a name="h3-Reading-characters">Reading characters</a></H3><PRE>
The <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG> and <STRONG>mvwgetch</STRONG>, routines read a
character from the window. In no-delay mode, if no input
is waiting, the value <STRONG>ERR</STRONG> is returned. In delay mode, the
called before another character is read.
-</PRE>
-<H3><a name="h3-Keypad-mode">Keypad mode</a></H3><PRE>
+</PRE><H3><a name="h3-Keypad-mode">Keypad mode</a></H3><PRE>
If <STRONG>keypad</STRONG> is <STRONG>TRUE</STRONG>, and a function key is pressed, the to-
ken for that function key is returned instead of the raw
- characters. Possible function keys are defined in <STRONG><curs-</STRONG>
- <STRONG>es.h></STRONG> as macros with values outside the range of 8-bit
- characters whose names begin with <STRONG>KEY_</STRONG>. Thus, a variable
- intended to hold the return value of a function key must
- be of short size or larger.
+ 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 char-
+ acters. Their names begin with <STRONG>KEY_</STRONG>.
+
+ <STRONG>o</STRONG> Other (user-defined) function keys which may be de-
+ fined 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 received (which, on modern terminals, means an es-
experience a delay between the time a user presses the es-
cape 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 pressed.
-</PRE>
-<H3><a name="h3-Ungetting-characters">Ungetting characters</a></H3><PRE>
+
+<
/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 windows.
-</PRE>
-<H3><a name="h3-Predefined-key-codes">Predefined key-codes</a></H3><PRE>
- The following special keys, defined in <STRONG><curses.h></STRONG>, may be
- returned by <STRONG>getch</STRONG> if <STRONG>keypad</STRONG> has been enabled. Not all of
- these are necessarily supported on any particular termi-
- nal.
+</PRE><H3><a name="h3-Predefined-key-codes">Predefined key-codes</a></H3><PRE>
+ The following special keys are defined in <STRONG><curses.h></STRONG>.
+
+ <STRONG>o</STRONG> Except for the special case <STRONG>KEY_RESIZE</STRONG>, it is neces-
+ sary 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 par-
+ ticular terminal.
+
+ <STRONG>o</STRONG> The naming convention may seem obscure, with some ap-
+ parent 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.
<EM>Name</EM> <EM>Key</EM> <EM>name</EM>
-------------------------------------------------
KEY_SR Scroll 1 line backward (reverse)
KEY_NPAGE Next page
KEY_PPAGE Previous page
+
KEY_STAB Set tab
KEY_CTAB Clear tab
KEY_CATAB Clear all tabs
KEY_FIND Find key
KEY_HELP Help key
KEY_MARK Mark key
-
KEY_MESSAGE Message key
KEY_MOUSE Mouse event read
KEY_MOVE Move key
KEY_SREDO Shifted redo key
KEY_SREPLACE Shifted replace key
KEY_SRIGHT Shifted right arrow
+
KEY_SRSUME Shifted resume key
KEY_SSAVE Shifted save key
KEY_SSUSPEND Shifted suspend key
+-----+------+-------+
| <STRONG>C1</STRONG> | <STRONG>down</STRONG> | <STRONG>C3</STRONG> |
+-----+------+-------+
- A few of these predefined values do <EM>not</EM> correspond to a
+ A few of these predefined values do <EM>not</EM> correspond to a
real key:
- <STRONG>o</STRONG> <STRONG>KEY_RESIZE</STRONG> is returned when the <STRONG>SIGWINCH</STRONG> signal has
- been detected (see <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG> and <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>).
+ <STRONG>o</STRONG> <STRONG>KEY_RESIZE</STRONG> is returned when the <STRONG>SIGWINCH</STRONG> signal has
+ been detected (see <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG> and <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>).
+ This code is returned 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>).
+ <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, because (e.g., with <EM>xterm</EM>
+ 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>
+</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 returns <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG> according to whether the
current terminal type recognizes a key with that value.
string (see <STRONG><A HREF="key_defined.3x.html">key_defined(3x)</A></STRONG>).
-</PRE>
-<H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
+</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
All routines return the integer <STRONG>ERR</STRONG> upon failure and an
- integer value other than <STRONG>ERR</STRONG> (<STRONG>OK</STRONG> in the case of ungetch())
+ integer value other than <STRONG>ERR</STRONG> (<STRONG>OK</STRONG> in the case of <STRONG>ungetch</STRONG>)
upon successful completion.
<STRONG>ungetch</STRONG>
<STRONG>wgetch</STRONG>
returns ERR if the window pointer is null, or if
- its timeout expires without having any data.
+ its timeout 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 move-
ment using <STRONG>wmove</STRONG>, and return an error if the position is
outside the window, or if the window pointer is null.
-</PRE>
-<H2><a name="h2-NOTES">NOTES</a></H2><PRE>
+</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
Use of the escape key by a programmer for a single charac-
ter function is discouraged, as it will cause a delay of
up to one second while the keypad code looks for a follow-
Ins key is usually mapped to <STRONG>KEY_IC</STRONG>.
-</PRE>
-<H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
The *get* functions are described in the XSI Curses stan-
dard, Issue 4. They read single-byte characters only.
The standard specifies that they return <STRONG>ERR</STRONG> on failure,
mentations) 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 re-
+ lated terminfo capabilities, but no higher-level functions
+ use the feature. The implementation in ncurses is an ex-
+ tension.
+
+ <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 in-
terrupt <STRONG>getch</STRONG>; (b) signal receipt interrupts <STRONG>getch</STRONG> and
- causes it to return ERR with <STRONG>errno</STRONG> set to <STRONG>EINTR</STRONG>. Under
- the <STRONG>ncurses</STRONG> implementation, handled signals never inter-
- rupt <STRONG>getch</STRONG>.
+ causes it to return ERR 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 using it be conditionalized on the <STRONG>NCURS-</STRONG>
<STRONG>ES_VERSION</STRONG> feature macro.
-</PRE>
-<H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
+</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_outopts.3x.html">curs_outopts(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_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG>re-</STRONG>
- <STRONG><A HREF="resizeterm.3x.html">sizeterm(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_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) li-
brary are described in <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>.
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