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37 <TITLE>curs_get_wch 3x 2024-05-11 ncurses 6.5 Library calls</TITLE>
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42 <H1 class="no-header">curs_get_wch 3x 2024-05-11 ncurses 6.5 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>wc</EM><STRONG>);</STRONG>
65 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
67 </PRE><H3><a name="h3-Reading-Characters">Reading Characters</a></H3><PRE>
68 <STRONG>wget_wch</STRONG> gathers a key event from the terminal keyboard associated with
69 a <EM>curses</EM> window <EM>win</EM>, returning <STRONG>OK</STRONG> if a wide character is read,
70 <STRONG>KEY_CODE_YES</STRONG> if a function key is read, and <STRONG>ERR</STRONG> if no key event is
71 available. <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG> describes the variants of this function.
73 When input is pending, <STRONG>wget_wch</STRONG> stores an integer identifying the key
74 event in <EM>wch</EM>; for alphanumeric and punctuation keys, this value
75 corresponds to the character encoding used by the terminal. Use of the
76 control key as a modifier, by holding it down while pressing and
77 releasing another key, often results in a distinct code. The behavior
78 of other keys depends on whether <EM>win</EM> is in keypad mode; see subsections
79 "Keypad Mode" and "Predefined Key Codes" in <STRONG><A HREF="curs_getch.3x.html">getch(3x)</A></STRONG>.
81 If no input is pending, then if the no-delay flag is set in the window
82 (see <STRONG><A HREF="nodelay.3x.html">nodelay(3x)</A></STRONG>), the function returns <STRONG>ERR</STRONG>; otherwise, <EM>curses</EM> waits
83 until the terminal has input. If <STRONG><A HREF="curs_inopts.3x.html">cbreak(3x)</A></STRONG> has been called, this
84 happens after one character is read. If <STRONG><A HREF="curs_inopts.3x.html">nocbreak(3x)</A></STRONG> has been called,
85 it occurs when the next newline is read. If <STRONG><A HREF="curs_inopts.3x.html">halfdelay(3x)</A></STRONG> has been
86 called, <EM>curses</EM> waits until input is available or the specified delay
89 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
90 <EM>wch</EM> to the window (at the cursor position) per the following rules.
92 <STRONG>o</STRONG> If <EM>wch</EM> matches the terminal's erase character, the cursor moves
93 leftward one position and the new position is erased as if
94 <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
95 keypad mode is enabled (see below), <STRONG>KEY_LEFT</STRONG> and <STRONG>KEY_BACKSPACE</STRONG> are
98 <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>.
100 <STRONG>o</STRONG> If the window <EM>win</EM> has been moved or modified since the last call to
101 <STRONG><A HREF="curs_refresh.3x.html">wrefresh(3x)</A></STRONG>, <EM>curses</EM> calls <STRONG>wrefresh</STRONG> on it.
103 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
104 the the character code for line feed in <EM>wch</EM> instead.
107 </PRE><H3><a name="h3-Ungetting-Characters">Ungetting Characters</a></H3><PRE>
108 <STRONG>unget_wch</STRONG> places <EM>wch</EM> into the input queue to be returned by the next
109 call to <STRONG>wget_wch</STRONG>. A single input queue serves all windows associated
113 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
114 <STRONG>wget_wch</STRONG> returns <STRONG>OK</STRONG> when it reads a wide character and <STRONG>KEY_CODE_YES</STRONG>
115 when it reads a function key code. It returns <STRONG>ERR</STRONG> if
117 <STRONG>o</STRONG> the <EM>WINDOW</EM> pointer is <STRONG>NULL</STRONG>, or
119 <STRONG>o</STRONG> its timeout expires without any data arriving, or
121 <STRONG>o</STRONG> execution was interrupted by a signal, in which case <STRONG>errno</STRONG> is set
122 to <STRONG>EINTR</STRONG>.
124 Functions prefixed with "mv" first perform cursor movement and fail if
125 the position (<EM>y</EM>, <EM>x</EM>) is outside the window boundaries.
127 <STRONG>unget_wch</STRONG> returns <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> if there is no more room in the
131 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
132 See the "NOTES" section of <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>.
134 All of these functions except <STRONG>wget_wch</STRONG> and <STRONG>unget_wch</STRONG> may be implemented
137 Unlike <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>, <STRONG>wget_wch</STRONG> and its variants store the value of the
138 input character in an additional <EM>wch</EM> parameter instead of the return
141 Unlike <STRONG>ungetch</STRONG>, <STRONG>unget_wch</STRONG> cannot distinguish function key codes from
142 conventional character codes. An application can overcome this
143 limitation by pushing function key codes with <STRONG>ungetch</STRONG> and subsequently
144 checking the return value of <STRONG>wget_wch</STRONG> for a match with <STRONG>KEY_CODE_YES</STRONG>.
147 </PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
148 See the "EXTENSIONS" section of <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>.
151 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
152 Applications employing <EM>ncurses</EM> extensions should condition their use on
153 the visibility of the <STRONG>NCURSES_VERSION</STRONG> preprocessor macro.
155 X/Open Curses, Issue 4 describes these functions. It specifies no
156 error conditions for them.
158 See the "PORTABILITY" section of <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> regarding the interaction
159 of <STRONG>wget_wch</STRONG> with signal handlers.
162 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
163 <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG> describes comparable functions of the <EM>ncurses</EM> library in
164 its non-wide-character configuration.
166 <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>,
167 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
171 ncurses 6.5 2024-05-11 <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>
175 <li><a href="#h2-NAME">NAME</a></li>
176 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
177 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
179 <li><a href="#h3-Reading-Characters">Reading Characters</a></li>
180 <li><a href="#h3-Ungetting-Characters">Ungetting Characters</a></li>
183 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
184 <li><a href="#h2-NOTES">NOTES</a></li>
185 <li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
186 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
187 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>