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30 * @Id: curs_getch.3x,v 1.41 2015/07/16 09:29:33 tom Exp @
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42 <H1 class="no-header">curs_getch 3x</H1>
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>
50 <H2><a name="h2-NAME">NAME</a></H2><PRE>
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><a name="h2-SYNOPSIS">SYNOPSIS</a></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><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
71 <H3><a name="h3-Reading-characters">Reading characters</a></H3><PRE>
72 The <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG> and <STRONG>mvwgetch</STRONG>, routines read a
73 character from the window. In no-delay mode, if no input
74 is waiting, the value <STRONG>ERR</STRONG> is returned. In delay mode, the
75 program waits until the system passes text through to the
76 program. Depending on the setting of <STRONG>cbreak</STRONG>, this is af-
77 ter one character (cbreak mode), or after the first new-
78 line (nocbreak mode). In half-delay mode, the program
79 waits until a character is typed or the specified timeout
82 If <STRONG>echo</STRONG> is enabled, and the window is not a pad, then the
83 character will also be echoed into the designated window
84 according to the following rules:
86 <STRONG>o</STRONG> If the character is the current erase character, left
87 arrow, or backspace, the cursor is moved one space to
88 the left and that screen position is erased as if
89 <STRONG>delch</STRONG> had been called.
91 <STRONG>o</STRONG> If the character value is any other <STRONG>KEY_</STRONG> define, the
92 user is alerted with a <STRONG>beep</STRONG> call.
94 <STRONG>o</STRONG> If the character is a carriage-return, and if <STRONG>nl</STRONG> is
95 enabled, it is translated to a line-feed after echo-
98 <STRONG>o</STRONG> Otherwise the character is simply output to the
101 If the window is not a pad, and it has been moved or modi-
102 fied since the last call to <STRONG>wrefresh</STRONG>, <STRONG>wrefresh</STRONG> will be
103 called before another character is read.
107 <H3><a name="h3-Keypad-mode">Keypad mode</a></H3><PRE>
108 If <STRONG>keypad</STRONG> is <STRONG>TRUE</STRONG>, and a function key is pressed, the to-
109 ken for that function key is returned instead of the raw
110 characters. Possible function keys are defined in <STRONG><curs-</STRONG>
111 <STRONG>es.h></STRONG> as macros with values outside the range of 8-bit
112 characters whose names begin with <STRONG>KEY_</STRONG>. Thus, a variable
113 intended to hold the return value of a function key must
114 be of short size or larger.
116 When a character that could be the beginning of a function
117 key is received (which, on modern terminals, means an es-
118 cape character), <STRONG>curses</STRONG> sets a timer. If the remainder of
119 the sequence does not come in within the designated time,
120 the character is passed through; otherwise, the function
121 key value is returned. For this reason, many terminals
122 experience a delay between the time a user presses the es-
123 cape key and the escape is returned to the program.
127 <H3><a name="h3-Ungetting-characters">Ungetting characters</a></H3><PRE>
128 The <STRONG>ungetch</STRONG> routine places <EM>ch</EM> back onto the input queue to
129 be returned by the next call to <STRONG>wgetch</STRONG>. There is just one
130 input queue for all windows.
134 <H3><a name="h3-Function-Keys">Function Keys</a></H3><PRE>
135 The following function keys, defined in <STRONG><curses.h></STRONG>, might
136 be returned by <STRONG>getch</STRONG> if <STRONG>keypad</STRONG> has been enabled. Note
137 that not all of these are necessarily supported on any
140 <EM>Name</EM> <EM>Key</EM> <EM>name</EM>
141 -------------------------------------------------
143 KEY_DOWN The four arrow keys ...
147 KEY_HOME Home key (upward+left arrow)
148 KEY_BACKSPACE Backspace
149 KEY_F0 Function keys; space for 64 keys
151 KEY_F(<EM>n</EM>) For 0 <= <EM>n</EM> <= 63
154 KEY_DC Delete character
155 KEY_IC Insert char or enter insert mode
156 KEY_EIC Exit insert char mode
157 KEY_CLEAR Clear screen
158 KEY_EOS Clear to end of screen
159 KEY_EOL Clear to end of line
160 KEY_SF Scroll 1 line forward
161 KEY_SR Scroll 1 line backward (reverse)
163 KEY_PPAGE Previous page
166 KEY_CATAB Clear all tabs
167 KEY_ENTER Enter or send
168 KEY_SRESET Soft (partial) reset
169 KEY_RESET Reset or hard reset
170 KEY_PRINT Print or copy
171 KEY_LL Home down or bottom (lower left)
172 KEY_A1 Upper left of keypad
173 KEY_A3 Upper right of keypad
174 KEY_B2 Center of keypad
175 KEY_C1 Lower left of keypad
176 KEY_C3 Lower right of keypad
177 KEY_BTAB Back tab key
178 KEY_BEG Beg(inning) key
179 KEY_CANCEL Cancel key
181 KEY_COMMAND Cmd (command) key
183 KEY_CREATE Create key
190 KEY_MESSAGE Message key
191 KEY_MOUSE Mouse event read
193 KEY_NEXT Next object key
195 KEY_OPTIONS Options key
196 KEY_PREVIOUS Previous object key
198 KEY_REFERENCE Ref(erence) key
199 KEY_REFRESH Refresh key
200 KEY_REPLACE Replace key
201 KEY_RESIZE Screen resized
202 KEY_RESTART Restart key
203 KEY_RESUME Resume key
205 KEY_SBEG Shifted beginning key
206 KEY_SCANCEL Shifted cancel key
207 KEY_SCOMMAND Shifted command key
208 KEY_SCOPY Shifted copy key
209 KEY_SCREATE Shifted create key
210 KEY_SDC Shifted delete char key
211 KEY_SDL Shifted delete line key
212 KEY_SELECT Select key
213 KEY_SEND Shifted end key
214 KEY_SEOL Shifted clear line key
215 KEY_SEXIT Shifted exit key
216 KEY_SFIND Shifted find key
217 KEY_SHELP Shifted help key
218 KEY_SHOME Shifted home key
219 KEY_SIC Shifted input key
220 KEY_SLEFT Shifted left arrow key
221 KEY_SMESSAGE Shifted message key
222 KEY_SMOVE Shifted move key
223 KEY_SNEXT Shifted next key
224 KEY_SOPTIONS Shifted options key
225 KEY_SPREVIOUS Shifted prev key
226 KEY_SPRINT Shifted print key
227 KEY_SREDO Shifted redo key
228 KEY_SREPLACE Shifted replace key
229 KEY_SRIGHT Shifted right arrow
230 KEY_SRSUME Shifted resume key
231 KEY_SSAVE Shifted save key
232 KEY_SSUSPEND Shifted suspend key
233 KEY_SUNDO Shifted undo key
234 KEY_SUSPEND Suspend key
237 Keypad is arranged like this:
240 +-----+------+-------+
241 | <STRONG>A1</STRONG> | <STRONG>up</STRONG> | <STRONG>A3</STRONG> |
242 +-----+------+-------+
243 |<STRONG>left</STRONG> | <STRONG>B2</STRONG> | <STRONG>right</STRONG> |
244 +-----+------+-------+
245 | <STRONG>C1</STRONG> | <STRONG>down</STRONG> | <STRONG>C3</STRONG> |
246 +-----+------+-------+
247 The <STRONG>has_key</STRONG> routine takes a key value from the above list,
248 and returns <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG> according to whether the current
249 terminal type recognizes a key with that value. Note that
250 a few values do not correspond to a real key, e.g.,
251 <STRONG>KEY_RESIZE</STRONG> and <STRONG>KEY_MOUSE</STRONG>. See <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG> and <STRONG>re-</STRONG>
252 <STRONG><A HREF="resizeterm.3x.html">sizeterm(3x)</A></STRONG> for more details about <STRONG>KEY_RESIZE</STRONG>, and
253 <STRONG><A HREF="curs_mouse.3x.html">curs_mouse(3x)</A></STRONG> for a discussion of <STRONG>KEY_MOUSE</STRONG>.
257 <H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
258 All routines return the integer <STRONG>ERR</STRONG> upon failure and an
259 integer value other than <STRONG>ERR</STRONG> (<STRONG>OK</STRONG> in the case of ungetch())
260 upon successful completion.
262 <STRONG>ungetch</STRONG>
263 returns ERR if there is no more room in the FIFO.
265 <STRONG>wgetch</STRONG>
266 returns ERR if the window pointer is null, or if
267 its timeout expires without having any data.
269 Functions with a "mv" prefix first perform a cursor move-
270 ment using <STRONG>wmove</STRONG>, and return an error if the position is
271 outside the window, or if the window pointer is null.
275 <H2><a name="h2-NOTES">NOTES</a></H2><PRE>
276 Use of the escape key by a programmer for a single charac-
277 ter function is discouraged, as it will cause a delay of
278 up to one second while the keypad code looks for a follow-
279 ing function-key sequence.
281 Note that some keys may be the same as commonly used con-
282 trol keys, e.g., <STRONG>KEY_ENTER</STRONG> versus control/M, <STRONG>KEY_BACKSPACE</STRONG>
283 versus control/H. Some curses implementations may differ
284 according to whether they treat these control keys spe-
285 cially (and ignore the terminfo), or use the terminfo def-
286 initions. <STRONG>Ncurses</STRONG> uses the terminfo definition. If it
287 says that <STRONG>KEY_ENTER</STRONG> is control/M, <STRONG>getch</STRONG> will return
288 <STRONG>KEY_ENTER</STRONG> when you press control/M.
290 Generally, <STRONG>KEY_ENTER</STRONG> denotes the character(s) sent by the
291 <EM>Enter</EM> key on the numeric keypad:
293 <STRONG>o</STRONG> the terminal description lists the most useful keys,
295 <STRONG>o</STRONG> the <EM>Enter</EM> key on the regular keyboard is already han-
296 dled by the standard ASCII characters for carriage-re-
299 <STRONG>o</STRONG> depending on whether <STRONG>nl</STRONG> or <STRONG>nonl</STRONG> was called, pressing
300 "Enter" on the regular keyboard may return either a
301 carriage-return or line-feed, and finally
303 <STRONG>o</STRONG> "Enter or send" is the standard description for this
306 When using <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, or <STRONG>mvwgetch</STRONG>, nocbreak
307 mode (<STRONG>nocbreak</STRONG>) and echo mode (<STRONG>echo</STRONG>) should not be used at
308 the same time. Depending on the state of the tty driver
309 when each character is typed, the program may produce un-
312 Note that <STRONG>getch</STRONG>, <STRONG>mvgetch</STRONG>, and <STRONG>mvwgetch</STRONG> may be macros.
314 Historically, the set of keypad macros was largely defined
315 by the extremely function-key-rich keyboard of the AT&T
316 7300, aka 3B1, aka Safari 4. Modern personal computers
317 usually have only a small subset of these. IBM PC-style
318 consoles typically support little more than <STRONG>KEY_UP</STRONG>,
319 <STRONG>KEY_DOWN</STRONG>, <STRONG>KEY_LEFT</STRONG>, <STRONG>KEY_RIGHT</STRONG>, <STRONG>KEY_HOME</STRONG>, <STRONG>KEY_END</STRONG>,
320 <STRONG>KEY_NPAGE</STRONG>, <STRONG>KEY_PPAGE</STRONG>, and function keys 1 through 12. The
321 Ins key is usually mapped to <STRONG>KEY_IC</STRONG>.
325 <H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
326 The *get* functions are described in the XSI Curses stan-
327 dard, Issue 4. They read single-byte characters only.
328 The standard specifies that they return <STRONG>ERR</STRONG> on failure,
329 but specifies no error conditions.
331 The echo behavior of these functions on input of <STRONG>KEY_</STRONG> or
332 backspace characters was not specified in the SVr4 docu-
333 mentation. This description is adopted from the XSI Curs-
336 The behavior of <STRONG>getch</STRONG> and friends in the presence of han-
337 dled signals is unspecified in the SVr4 and XSI Curses
338 documentation. Under historical curses implementations,
339 it varied depending on whether the operating system's im-
340 plementation of handled signal receipt interrupts a
341 <STRONG>read(2)</STRONG> call in progress or not, and also (in some imple-
342 mentations) depending on whether an input timeout or non-
343 blocking mode has been set.
345 Programmers concerned about portability should be prepared
346 for either of two cases: (a) signal receipt does not in-
347 terrupt <STRONG>getch</STRONG>; (b) signal receipt interrupts <STRONG>getch</STRONG> and
348 causes it to return ERR with <STRONG>errno</STRONG> set to <STRONG>EINTR</STRONG>. Under
349 the <STRONG>ncurses</STRONG> implementation, handled signals never inter-
350 rupt <STRONG>getch</STRONG>.
352 The <STRONG>has_key</STRONG> function is unique to <STRONG>ncurses</STRONG>. We recommend
353 that any code using it be conditionalized on the <STRONG>NCURS-</STRONG>
354 <STRONG>ES_VERSION</STRONG> feature macro.
358 <H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
359 <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>,
360 <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>
361 <STRONG><A HREF="resizeterm.3x.html">sizeterm(3x)</A></STRONG>.
363 Comparable functions in the wide-character (ncursesw) li-
364 brary are described in <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>.
368 <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>
372 <li><a href="#h2-NAME">NAME</a></li>
373 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
374 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
376 <li><a href="#h3-Reading-characters">Reading characters</a></li>
377 <li><a href="#h3-Keypad-mode">Keypad mode</a></li>
378 <li><a href="#h3-Ungetting-characters">Ungetting characters</a></li>
379 <li><a href="#h3-Function-Keys">Function Keys</a></li>
382 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
383 <li><a href="#h2-NOTES">NOTES</a></li>
384 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
385 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>