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37 <TITLE>curs_get_wch 3x 2023-12-23 ncurses 6.4 Library calls</TITLE>
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42 <H1 class="no-header">curs_get_wch 3x 2023-12-23 ncurses 6.4 Library calls</H1>
44 <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>
49 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
50 <STRONG>get_wch</STRONG>, <STRONG>wget_wch</STRONG>, <STRONG>mvget_wch</STRONG>, <STRONG>mvwget_wch</STRONG>, <STRONG>unget_wch</STRONG> - get (or push
51 back) a wide character from <EM>curses</EM> terminal keyboard
54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
55 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
57 <STRONG>int</STRONG> <STRONG>get_wch(wint_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
58 <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>
59 <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>
60 <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>
62 <STRONG>int</STRONG> <STRONG>unget_wch(const</STRONG> <STRONG>wchar_t</STRONG> <EM>wch</EM><STRONG>);</STRONG>
65 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
67 </PRE><H3><a name="h3-wget_wch">wget_wch</a></H3><PRE>
68 The <STRONG>get_wch</STRONG>, <STRONG>wget_wch</STRONG>, <STRONG>mvget_wch</STRONG>, and <STRONG>mvwget_wch</STRONG> functions read a
69 character from the terminal associated with the current or specified
70 window. In no-delay mode, if no input is waiting, the value <STRONG>ERR</STRONG> is
71 returned. In delay mode, the program waits until the system passes
72 text through to the program. Depending on the setting of <STRONG>cbreak</STRONG>, this
73 is after one character (cbreak mode), or after the first newline
74 (nocbreak mode). In half-delay mode, the program waits until the user
75 types a character or the specified timeout interval has elapsed.
77 Unless <STRONG>noecho</STRONG> has been set, these routines echo the character into the
80 If the window is not a pad and has been moved or modified since the
81 last call to <STRONG>wrefresh</STRONG>, <STRONG>wrefresh</STRONG> will be called before another character
84 If <STRONG>keypad</STRONG> is enabled, these functions respond to the pressing of a
85 function key by setting the object pointed to by <EM>wch</EM> to the keycode
86 assigned to the function key, and returning <STRONG>KEY_CODE_YES</STRONG>. If a
87 character (such as escape) that could be the beginning of a function
88 key is received, curses sets a timer. If the remainder of the sequence
89 does arrive within the designated time, curses passes through the
90 character; otherwise, curses returns the function key value. For this
91 reason, many terminals experience a delay between the time a user
92 presses the escape key and the time the escape is returned to the
95 The keycodes returned by these functions are the same as those returned
96 by <STRONG>wgetch</STRONG>:
98 <STRONG>o</STRONG> The predefined function keys are listed in <STRONG><curses.h></STRONG> as macros
99 with values outside the range of 8-bit characters. Their names
100 begin with <STRONG>KEY_</STRONG>.
102 <STRONG>o</STRONG> Other (user-defined) function keys which may be defined using
103 <STRONG><A HREF="define_key.3x.html">define_key(3x)</A></STRONG> have no names, but also are expected to have values
104 outside the range of 8-bit characters.
107 </PRE><H3><a name="h3-unget_wch">unget_wch</a></H3><PRE>
108 The <STRONG>unget_wch</STRONG> function pushes the wide character <EM>wch</EM> back onto the head
109 of the input queue, so the wide character is returned by the next call
110 to <STRONG>get_wch</STRONG>. The pushback of one character is guaranteed. If the
111 program calls <STRONG>unget_wch</STRONG> too many times without an intervening call to
112 <STRONG>get_wch</STRONG>, the operation may fail.
114 Unlike <STRONG>ungetch</STRONG> and <STRONG>wgetch</STRONG>, <STRONG>unget_wch</STRONG> cannot distinguish special
115 characters returned by <STRONG>wget_wch</STRONG> from ordinary characters. An
116 application can push special keys which it may read via <STRONG>wget_wch</STRONG> by
117 checking for the <STRONG>KEY_CODE_YES</STRONG> result, and using <STRONG>ungetch</STRONG> for those
121 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
122 When <STRONG>get_wch</STRONG>, <STRONG>wget_wch</STRONG>, <STRONG>mvget_wch</STRONG>, and <STRONG>mvwget_wch</STRONG> functions
123 successfully report the pressing of a function key, they return
124 <STRONG>KEY_CODE_YES</STRONG>. When they successfully report a wide character, they
125 return <STRONG>OK</STRONG>. Otherwise, they return <STRONG>ERR</STRONG>.
127 Upon successful completion, <STRONG>unget_wch</STRONG> returns <STRONG>OK</STRONG>. Otherwise, the
128 function returns <STRONG>ERR</STRONG>.
130 Functions with a "mv" prefix first perform a cursor movement using
131 <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
132 the window pointer is null.
135 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
136 Applications should not define the escape key by itself as a single-
139 When using <STRONG>get_wch</STRONG>, <STRONG>wget_wch</STRONG>, <STRONG>mvget_wch</STRONG>, or <STRONG>mvwget_wch</STRONG>, applications
140 should not use <STRONG>nocbreak</STRONG> mode and <STRONG>echo</STRONG> mode at the same time. Depending
141 on the state of the tty driver when each character is typed, the
142 program may produce undesirable results.
144 All of these functions except <STRONG>wget_wch</STRONG> and <STRONG>unget_wch</STRONG> may be implemented
148 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
149 These functions are described in the XSI Curses standard, Issue 4.
152 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
153 <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_inopts.3x.html">curs_inopts(3x)</A></STRONG>, <STRONG><A HREF="curs_ins_wch.3x.html">curs_ins_wch(3x)</A></STRONG>,
154 <STRONG><A HREF="curs_move.3x.html">curs_move(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
158 ncurses 6.4 2023-12-23 <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>
162 <li><a href="#h2-NAME">NAME</a></li>
163 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
164 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
166 <li><a href="#h3-wget_wch">wget_wch</a></li>
167 <li><a href="#h3-unget_wch">unget_wch</a></li>
170 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
171 <li><a href="#h2-NOTES">NOTES</a></li>
172 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
173 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>