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- * @Id: curs_get_wch.3x,v 1.8 2012/11/03 23:03:59 tom Exp @
+ * @Id: curs_get_wch.3x,v 1.40 2024/04/20 19:23:03 tom Exp @
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-<H1>curs_get_wch 3x</H1>
-<HR>
+<H1 class="no-header">curs_get_wch 3x 2024-04-20 ncurses 6.4 Library calls</H1>
<PRE>
-<STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>
<STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>
+<STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>
Library calls <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>
-</PRE>
-<H2><a name="h2-NAME">NAME</a></H2><PRE>
- <STRONG>get_wch</STRONG>, <STRONG>wget_wch</STRONG>, <STRONG>mvget_wch</STRONG>, <STRONG>mvwget_wch</STRONG>, <STRONG>unget_wch</STRONG> - get
- (or push back) a wide character from curses terminal key-
- board
+</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
+ <STRONG>get_wch</STRONG>, <STRONG>wget_wch</STRONG>, <STRONG>mvget_wch</STRONG>, <STRONG>mvwget_wch</STRONG>, <STRONG>unget_wch</STRONG> - get (or push
+ back) a wide character from <EM>curses</EM> 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>get_wch(wint_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wget_wch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>wint_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>mvget_wch(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>wint_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>mvwget_wch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>wint_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
- <STRONG>int</STRONG> <STRONG>unget_wch(const</STRONG> <STRONG>wchar_t</STRONG> <EM>wch</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>unget_wch(const</STRONG> <STRONG>wchar_t</STRONG> <EM>wc</EM><STRONG>);</STRONG>
-</PRE>
-<H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
- The <STRONG>get_wch</STRONG>, <STRONG>wget_wch</STRONG>, <STRONG>mvget_wch</STRONG>, and <STRONG>mvwget_wch</STRONG> functions
- read a character from the terminal associated with the
- current or specified window. In no-delay mode, if no
- input is waiting, the value <STRONG>ERR</STRONG> is 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 the user types a character
- or the specified timeout interval has elapsed.
-
- Unless <STRONG>noecho</STRONG> has been set, these routines echo the char-
- acter into the designated window.
-
- If the window is not a pad and has been moved or modified
- since the last call to <STRONG>wrefresh</STRONG>, <STRONG>wrefresh</STRONG> will be called
- before another character is read.
-
- If <STRONG>keypad</STRONG> is enabled, these functions respond to the
- pressing of a function key by setting the object pointed
- to by <EM>wch</EM> to the corresponding <STRONG>KEY_</STRONG> value defined in
- <STRONG><curses.h></STRONG> and returning <STRONG>KEY_CODE_YES</STRONG>. If a character
- (such as escape) that could be the beginning of a function
- key is received, curses sets a timer. If the remainder of
- the sequence does arrive within the designated time,
- curses passes through the character; otherwise, curses
- returns the function key value. For this reason, many
- terminals experience a delay between the time a user
- presses the escape key and the time the escape is returned
- to the program.
-
- The <STRONG>unget_wch</STRONG> function pushes the wide character <EM>wch</EM> back
- onto the head of the input queue, so the wide character is
- returned by the next call to <STRONG>get_wch</STRONG>. The pushback of one
- character is guaranteed. If the program calls <STRONG>unget_wch</STRONG>
- too many times without an intervening call to <STRONG>get_wch</STRONG>, the
- operation may fail.
+</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
-</PRE>
-<H2><a name="h2-NOTES">NOTES</a></H2><PRE>
- The header file <STRONG><curses.h></STRONG> automatically includes the
- header file <STRONG><stdio.h></STRONG>.
+</PRE><H3><a name="h3-Reading-Characters">Reading Characters</a></H3><PRE>
+ <STRONG>wget_wch</STRONG> gathers a key stroke <EM>wch</EM> from the terminal keyboard associated
+ with a <EM>curses</EM> window <EM>win</EM>, returning <STRONG>OK</STRONG> if a wide character is read,
+ <STRONG>KEY_CODE_YES</STRONG> if a function key is read, and <STRONG>ERR</STRONG> if no key event is
+ available. <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG> describes the variants of this function.
- Applications should not define the escape key by itself as
- a single-character function.
+ When input is pending, <STRONG>wget_wch</STRONG> stores an integer identifying the key
+ stroke in <EM>wch</EM>; for alphanumeric and punctuation keys, this value
+ corresponds to the character encoding used by the terminal. Use of the
+ control key as a modifier often results in a distinct code. The
+ behavior of other keys depends on whether <EM>win</EM> is in keypad mode; see
+ subsections "Keypad Mode" and "Predefined Key Codes" in <STRONG><A HREF="curs_getch.3x.html">getch(3x)</A></STRONG>.
- When using <STRONG>get_wch</STRONG>, <STRONG>wget_wch</STRONG>, <STRONG>mvget_wch</STRONG>, or <STRONG>mvwget_wch</STRONG>,
- applications should not use <STRONG>nocbreak</STRONG> mode and <STRONG>echo</STRONG> mode at
- the same time. Depending on the state of the tty driver
- when each character is typed, the program may produce
- undesirable results.
+ If no input is pending, then if the no-delay flag is set in the window
+ (see <STRONG><A HREF="nodelay.3x.html">nodelay(3x)</A></STRONG>), the function returns <STRONG>ERR</STRONG>; otherwise, <EM>curses</EM> waits
+ until the terminal has input. If <STRONG><A HREF="curs_inopts.3x.html">cbreak(3x)</A></STRONG> has been called, this
+ happens after one character is read. If <STRONG><A HREF="curs_inopts.3x.html">nocbreak(3x)</A></STRONG> has been called,
+ it occurs when the next newline is read. If <STRONG><A HREF="curs_inopts.3x.html">halfdelay(3x)</A></STRONG> has been
+ called, <EM>curses</EM> waits until a character is typed or the specified delay
+ elapses.
- All functions except <STRONG>wget_wch</STRONG> and <STRONG>unget_wch</STRONG> may be macros.
+ If <STRONG><A HREF="curs_inopts.3x.html">echo(3x)</A></STRONG> has been called, and the window is not a pad, <EM>curses</EM> writes
+ <EM>wch</EM> to the window (at the cursor position) per the following rules.
+ <STRONG>o</STRONG> If <EM>wch</EM> matches the terminal's erase character, the cursor moves
+ leftward one position and the new position is erased as if
+ <STRONG><A HREF="curs_move.3x.html">wmove(3x)</A></STRONG> and then <STRONG><A HREF="curs_delch.3x.html">wdelch(3x)</A></STRONG> were called. When the window's
+ keypad mode is enabled (see below), <STRONG>KEY_LEFT</STRONG> and <STRONG>KEY_BACKSPACE</STRONG> are
+ handled the same way.
-</PRE>
-<H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- When <STRONG>get_wch</STRONG>, <STRONG>wget_wch</STRONG>, <STRONG>mvget_wch</STRONG>, and <STRONG>mvwget_wch</STRONG> func-
- tions successfully report the pressing of a function key,
- they return <STRONG>KEY_CODE_YES</STRONG>. When they successfully report a
- wide character, they return <STRONG>OK</STRONG>. Otherwise, they return
- <STRONG>ERR</STRONG>.
+ <STRONG>o</STRONG> <EM>curses</EM> writes any other <EM>wch</EM> to the window, as with <STRONG><A HREF="curs_add_wch.3x.html">wecho_wchar(3x)</A></STRONG>.
- Upon successful completion, <STRONG>unget_wch</STRONG> returns <STRONG>OK</STRONG>. Other-
- wise, the function returns <STRONG>ERR</STRONG>.
+ <STRONG>o</STRONG> If the window has been moved or modified since the last call to
+ <STRONG><A HREF="curs_refresh.3x.html">wrefresh(3x)</A></STRONG>, <EM>curses</EM> calls <STRONG>wrefresh</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.
+ If <EM>wch</EM> is a carriage return and <STRONG><A HREF="curs_inopts.3x.html">nl(3x)</A></STRONG> has been called, <STRONG>wgetch</STRONG> stores
+ the the character code for newline (line feed) in <EM>wch</EM> instead.
-</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_ins_wch.3x.html">curs_ins_wch(3x)</A></STRONG>,
- <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(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>
+</PRE><H3><a name="h3-Ungetting-Characters">Ungetting Characters</a></H3><PRE>
+ <STRONG>unget_wch</STRONG> places <EM>wch</EM> into the input queue to be returned by the next
+ call to <STRONG>wget_wch</STRONG>. A single input queue serves all windows.
+
+
+</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
+ <STRONG>wget_wch</STRONG> returns <STRONG>OK</STRONG> when it reads a wide character and <STRONG>KEY_CODE_YES</STRONG>
+ when it reads a function key code. It returns <STRONG>ERR</STRONG> if
+
+ <STRONG>o</STRONG> the <EM>WINDOW</EM> pointer is <STRONG>NULL</STRONG>, or
+
+ <STRONG>o</STRONG> its timeout expires without any data arriving, or
+
+ <STRONG>o</STRONG> execution was interrupted by a signal, in which case <STRONG>errno</STRONG> is set
+ to <STRONG>EINTR</STRONG>.
+
+ Functions prefixed with "mv" first perform cursor movement and fail if
+ the position (<EM>y</EM>, <EM>x</EM>) is outside the window boundaries.
+
+ <STRONG>unget_wch</STRONG> returns <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> if there is no more room in the
+ input queue.
+
+
+</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
+ See the "NOTES" section of <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>.
+ All of these functions except <STRONG>wget_wch</STRONG> and <STRONG>unget_wch</STRONG> may be implemented
+ as macros.
+ Unlike <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>, <STRONG>wget_wch</STRONG> and its variants store the value of the
+ input character in an additional <EM>wch</EM> parameter instead of the return
+ value.
- <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>
+ Unlike <STRONG>ungetch</STRONG>, <STRONG>unget_wch</STRONG> cannot distinguish function key codes
+ <STRONG>wget_wch</STRONG> from conventional character codes. An application can
+ overcome this limitation by pushing function key codes with <STRONG>ungetch</STRONG> and
+ subsequently checking the return value of <STRONG>wget_wch</STRONG> for a match with
+ <STRONG>KEY_CODE_YES</STRONG>.
+
+
+</PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
+ See the "EXTENSIONS" section of <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>.
+
+
+</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.
+
+ X/Open Curses, Issue 4 describes these functions. It specifies no
+ error conditions for them.
+
+ See the "PORTABILITY" section of <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> regarding the interaction
+ of <STRONG>wget_wch</STRONG> with signal handlers.
+
+
+</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
+ <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG> describes comparable functions of the <EM>ncurses</EM> library in
+ its non-wide-character configuration.
+
+ <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>, <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(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>
+
+
+
+ncurses 6.4 2024-04-20 <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(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></li>
-<li><a href="#h2-NOTES">NOTES</a></li>
+<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
+<ul>
+<li><a href="#h3-Reading-Characters">Reading Characters</a></li>
+<li><a href="#h3-Ungetting-Characters">Ungetting Characters</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-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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