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31 * @Id: curs_getch.3x,v 1.30 2006/12/02 17:02:53 tom Exp @
35 <TITLE>curs_getch 3x</TITLE>
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40 <H1>curs_getch 3x</H1>
43 <!-- Manpage converted by man2html 3.0.1 -->
44 <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG> <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>
51 <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, <STRONG>mvwgetch</STRONG>, <STRONG>ungetch</STRONG>, <STRONG>has_key</STRONG> - get
52 (or push back) characters from <STRONG>curses</STRONG> terminal keyboard
56 <H2>SYNOPSIS</H2><PRE>
57 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
59 <STRONG>int</STRONG> <STRONG>getch(void);</STRONG>
60 <STRONG>int</STRONG> <STRONG>wgetch(WINDOW</STRONG> <STRONG>*win);</STRONG>
61 <STRONG>int</STRONG> <STRONG>mvgetch(int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x);</STRONG>
62 <STRONG>int</STRONG> <STRONG>mvwgetch(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x);</STRONG>
63 <STRONG>int</STRONG> <STRONG>ungetch(int</STRONG> <STRONG>ch);</STRONG>
64 <STRONG>int</STRONG> <STRONG>has_key(int</STRONG> <STRONG>ch);</STRONG>
68 <H2>DESCRIPTION</H2><PRE>
69 The <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG> and <STRONG>mvwgetch</STRONG>, routines read a
70 character from the window. In no-delay mode, if no input
71 is waiting, the value <STRONG>ERR</STRONG> is returned. In delay mode, the
72 program waits until the system passes text through to the
73 program. Depending on the setting of <STRONG>cbreak</STRONG>, this is af-
74 ter one character (cbreak mode), or after the first new-
75 line (nocbreak mode). In half-delay mode, the program
76 waits until a character is typed or the specified timeout
79 Unless <STRONG>noecho</STRONG> has been set, then the character will also
80 be echoed into the designated window according to the fol-
81 lowing rules: If the character is the current erase char-
82 acter, left arrow, or backspace, the cursor is moved one
83 space to the left and that screen position is erased as if
84 <STRONG>delch</STRONG> had been called. If the character value is any oth-
85 er <STRONG>KEY_</STRONG> define, the user is alerted with a <STRONG>beep</STRONG> call.
86 Otherwise the character is simply output to the screen.
88 If the window is not a pad, and it has been moved or modi-
89 fied since the last call to <STRONG>wrefresh</STRONG>, <STRONG>wrefresh</STRONG> will be
90 called before another character is read.
92 If <STRONG>keypad</STRONG> is <STRONG>TRUE</STRONG>, and a function key is pressed, the to-
93 ken for that function key is returned instead of the raw
94 characters. Possible function keys are defined in <STRONG><curs-</STRONG>
95 <STRONG>es.h></STRONG> as macros with values outside the range of 8-bit
96 characters whose names begin with <STRONG>KEY_</STRONG>. Thus, a variable
97 intended to hold the return value of a function key must
98 be of short size or larger.
100 When a character that could be the beginning of a function
101 key is received (which, on modern terminals, means an es-
102 cape character), <STRONG>curses</STRONG> sets a timer. If the remainder of
103 the sequence does not come in within the designated time,
104 the character is passed through; otherwise, the function
105 key value is returned. For this reason, many terminals
106 experience a delay between the time a user presses the es-
107 cape key and the escape is returned to the program.
109 The <STRONG>ungetch</STRONG> routine places <EM>ch</EM> back onto the input queue to
110 be returned by the next call to <STRONG>wgetch</STRONG>. There is just one
111 input queue for all windows.
114 <STRONG>Function</STRONG> <STRONG>Keys</STRONG>
115 The following function keys, defined in <STRONG><curses.h></STRONG>, might
116 be returned by <STRONG>getch</STRONG> if <STRONG>keypad</STRONG> has been enabled. Note
117 that not all of these are necessarily supported on any
121 <EM>Name</EM> <EM>Key</EM> <EM>name</EM>
123 KEY_DOWN The four arrow keys ...
127 KEY_HOME Home key (upward+left arrow)
128 KEY_BACKSPACE Backspace
129 KEY_F0 Function keys; space for 64 keys
131 KEY_F(<EM>n</EM>) For 0 <= <EM>n</EM> <= 63
134 KEY_DC Delete character
135 KEY_IC Insert char or enter insert mode
136 KEY_EIC Exit insert char mode
137 KEY_CLEAR Clear screen
138 KEY_EOS Clear to end of screen
139 KEY_EOL Clear to end of line
140 KEY_SF Scroll 1 line forward
141 KEY_SR Scroll 1 line backward (reverse)
143 KEY_PPAGE Previous page
146 KEY_CATAB Clear all tabs
147 KEY_ENTER Enter or send
148 KEY_SRESET Soft (partial) reset
149 KEY_RESET Reset or hard reset
150 KEY_PRINT Print or copy
151 KEY_LL Home down or bottom (lower left)
152 KEY_A1 Upper left of keypad
153 KEY_A3 Upper right of keypad
154 KEY_B2 Center of keypad
155 KEY_C1 Lower left of keypad
156 KEY_C3 Lower right of keypad
157 KEY_BTAB Back tab key
158 KEY_BEG Beg(inning) key
159 KEY_CANCEL Cancel key
161 KEY_COMMAND Cmd (command) key
163 KEY_CREATE Create key
169 KEY_MESSAGE Message key
170 KEY_MOUSE Mouse event read
172 KEY_NEXT Next object key
174 KEY_OPTIONS Options key
175 KEY_PREVIOUS Previous object key
177 KEY_REFERENCE Ref(erence) key
178 KEY_REFRESH Refresh key
179 KEY_REPLACE Replace key
180 KEY_RESIZE Screen resized
181 KEY_RESTART Restart key
182 KEY_RESUME Resume key
185 KEY_SBEG Shifted beginning key
186 KEY_SCANCEL Shifted cancel key
187 KEY_SCOMMAND Shifted command key
188 KEY_SCOPY Shifted copy key
189 KEY_SCREATE Shifted create key
190 KEY_SDC Shifted delete char key
191 KEY_SDL Shifted delete line key
192 KEY_SELECT Select key
193 KEY_SEND Shifted end key
194 KEY_SEOL Shifted clear line key
195 KEY_SEXIT Shifted exit key
196 KEY_SFIND Shifted find key
197 KEY_SHELP Shifted help key
198 KEY_SHOME Shifted home key
199 KEY_SIC Shifted input key
200 KEY_SLEFT Shifted left arrow key
201 KEY_SMESSAGE Shifted message key
202 KEY_SMOVE Shifted move key
203 KEY_SNEXT Shifted next key
204 KEY_SOPTIONS Shifted options key
205 KEY_SPREVIOUS Shifted prev key
206 KEY_SPRINT Shifted print key
207 KEY_SREDO Shifted redo key
208 KEY_SREPLACE Shifted replace key
209 KEY_SRIGHT Shifted right arrow
210 KEY_SRSUME Shifted resume key
211 KEY_SSAVE Shifted save key
212 KEY_SSUSPEND Shifted suspend key
213 KEY_SUNDO Shifted undo key
214 KEY_SUSPEND Suspend key
217 Keypad is arranged like this:
220 +-----+------+-------+
221 | <STRONG>A1</STRONG> | <STRONG>up</STRONG> | <STRONG>A3</STRONG> |
222 +-----+------+-------+
223 |<STRONG>left</STRONG> | <STRONG>B2</STRONG> | <STRONG>right</STRONG> |
224 +-----+------+-------+
225 | <STRONG>C1</STRONG> | <STRONG>down</STRONG> | <STRONG>C3</STRONG> |
226 +-----+------+-------+
227 The <STRONG>has_key</STRONG> routine takes a key value from the above list,
228 and returns TRUE or FALSE according to whether the current
229 terminal type recognizes a key with that value. Note that
230 a few values do not correspond to a real key, e.g.,
231 <STRONG>KEY_RESIZE</STRONG> and <STRONG>KEY_MOUSE</STRONG>. See <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG> for more de-
232 tails about <STRONG>KEY_RESIZE</STRONG>, and <STRONG><A HREF="curs_mouse.3x.html">curs_mouse(3x)</A></STRONG> for a discus-
233 sion of <STRONG>KEY_MOUSE</STRONG>.
238 <H2>RETURN VALUE</H2><PRE>
239 All routines return the integer <STRONG>ERR</STRONG> upon failure and an
240 integer value other than <STRONG>ERR</STRONG> (<STRONG>OK</STRONG> in the case of ungetch())
241 upon successful completion.
243 <STRONG>ungetch</STRONG>
244 returns an error if there is no more room in
247 <STRONG>wgetch</STRONG>
248 returns an error if the window pointer is
249 null, or if its timeout expires without having
255 Use of the escape key by a programmer for a single charac-
256 ter function is discouraged, as it will cause a delay of
257 up to one second while the keypad code looks for a follow-
258 ing function-key sequence.
260 Note that some keys may be the same as commonly used con-
261 trol keys, e.g., <STRONG>KEY_ENTER</STRONG> versus control/M, <STRONG>KEY_BACKSPACE</STRONG>
262 versus control/H. Some curses implementations may differ
263 according to whether they treat these control keys spe-
264 cially (and ignore the terminfo), or use the terminfo def-
265 initions. <STRONG>Ncurses</STRONG> uses the terminfo definition. If it
266 says that <STRONG>KEY_ENTER</STRONG> is control/M, <STRONG>getch</STRONG> will return
267 <STRONG>KEY_ENTER</STRONG> when you press control/M.
269 When using <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, or <STRONG>mvwgetch</STRONG>, nocbreak
270 mode (<STRONG>nocbreak</STRONG>) and echo mode (<STRONG>echo</STRONG>) should not be used at
271 the same time. Depending on the state of the tty driver
272 when each character is typed, the program may produce un-
275 Note that <STRONG>getch</STRONG>, <STRONG>mvgetch</STRONG>, and <STRONG>mvwgetch</STRONG> may be macros.
277 Historically, the set of keypad macros was largely defined
278 by the extremely function-key-rich keyboard of the AT&T
279 7300, aka 3B1, aka Safari 4. Modern personal computers
280 usually have only a small subset of these. IBM PC-style
281 consoles typically support little more than <STRONG>KEY_UP</STRONG>,
282 <STRONG>KEY_DOWN</STRONG>, <STRONG>KEY_LEFT</STRONG>, <STRONG>KEY_RIGHT</STRONG>, <STRONG>KEY_HOME</STRONG>, <STRONG>KEY_END</STRONG>,
283 <STRONG>KEY_NPAGE</STRONG>, <STRONG>KEY_PPAGE</STRONG>, and function keys 1 through 12. The
284 Ins key is usually mapped to <STRONG>KEY_IC</STRONG>.
288 <H2>PORTABILITY</H2><PRE>
289 The *get* functions are described in the XSI Curses stan-
290 dard, Issue 4. They read single-byte characters only.
291 The standard specifies that they return <STRONG>ERR</STRONG> on failure,
292 but specifies no error conditions.
294 The echo behavior of these functions on input of <STRONG>KEY_</STRONG> or
295 backspace characters was not specified in the SVr4 docu-
296 mentation. This description is adopted from the XSI Curs-
299 The behavior of <STRONG>getch</STRONG> and friends in the presence of han-
300 dled signals is unspecified in the SVr4 and XSI Curses
301 documentation. Under historical curses implementations,
302 it varied depending on whether the operating system's im-
303 plementation of handled signal receipt interrupts a
304 <STRONG><A HREF="read.2.html">read(2)</A></STRONG> call in progress or not, and also (in some imple-
305 mentations) depending on whether an input timeout or non-
306 blocking mode has been set.
308 Programmers concerned about portability should be prepared
309 for either of two cases: (a) signal receipt does not in-
310 terrupt <STRONG>getch</STRONG>; (b) signal receipt interrupts <STRONG>getch</STRONG> and
311 causes it to return ERR with <STRONG>errno</STRONG> set to <STRONG>EINTR</STRONG>. Under
312 the <STRONG>ncurses</STRONG> implementation, handled signals never inter-
313 rupt <STRONG>getch</STRONG>.
315 The <STRONG>has_key</STRONG> function is unique to <STRONG>ncurses</STRONG>. We recommend
316 that any code using it be conditionalized on the <STRONG>NCURS-</STRONG>
317 <STRONG>ES_VERSION</STRONG> feature macro.
321 <H2>SEE ALSO</H2><PRE>
322 <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>,
323 <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="resizeterm.3x.html">resizeterm(3x)</A></STRONG>.
325 Comparable functions in the wide-character (ncursesw) li-
326 brary are described in <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>.
330 <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>
334 Man(1) output converted with
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