2 <BODY BGCOLOR="#99ccbb" TEXT="#000000" LINK="#4060b0" VLINK="#000080" ALINK="#ff4040">
4 <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, <STRONG>mvwgetch</STRONG>, <STRONG>ungetch</STRONG> - get (or push
5 back) characters from <STRONG>curses</STRONG> terminal keyboard
10 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
12 <STRONG>int</STRONG> <STRONG>getch(void);</STRONG>
13 <STRONG>int</STRONG> <STRONG>wgetch(WINDOW</STRONG> <STRONG>*win);</STRONG>
14 <STRONG>int</STRONG> <STRONG>mvgetch(int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x);</STRONG>
15 <STRONG>int</STRONG> <STRONG>mvwgetch(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x);</STRONG>
16 <STRONG>int</STRONG> <STRONG>ungetch(int</STRONG> <STRONG>ch);</STRONG>
17 <STRONG>int</STRONG> <STRONG>has_key(int</STRONG> <STRONG>ch);</STRONG>
21 <H2>DESCRIPTION</H2><PRE>
22 The <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG> and <STRONG>mvwgetch</STRONG>, routines read a
23 character from the window. In no-delay mode, if no input
24 is waiting, the value <STRONG>ERR</STRONG> is returned. In delay mode, the
25 program waits until the system passes text through to the
26 program. Depending on the setting of <STRONG>cbreak</STRONG>, this is
27 after one character (cbreak mode), or after the first new-
28 line (nocbreak mode). In half-delay mode, the program
29 waits until a character is typed or the specified timeout
32 If <STRONG>noecho</STRONG> has been set, then the character will also be
33 echoed into the designated window according to the follow-
34 ing rules: If the character is the current erase charac-
35 ter, left arrow, or backspace, the cursor is moved one
36 space to the left and that screen position is erased as if
37 <STRONG>delch</STRONG> had been called. If the character value is any
38 other <STRONG>KEY_</STRONG> define, the user is alerted with a <STRONG>beep</STRONG> call.
39 Otherwise the character is simply output to the screen.
41 If the window is not a pad, and it has been moved or modi-
42 fied since the last call to <STRONG>wrefresh</STRONG>, <STRONG>wrefresh</STRONG> will be
43 called before another character is read.
45 If <STRONG>keypad</STRONG> is <STRONG>TRUE</STRONG>, and a function key is pressed, the
46 token for that function key is returned instead of the raw
47 characters. Possible function keys are defined in
48 <STRONG><curses.h></STRONG> as macros with values outside the range of
49 8-bit characters whose names begin with <STRONG>KEY_.</STRONG> Thus, a
50 variable intended to hold the return value of a function
51 key must be of short size or larger.
53 When a character that could be the beginning of a function
54 key is received (which, on modern terminals, means an
55 escape character), <STRONG>curses</STRONG> sets a timer. If the remainder
56 of the sequence does not come in within the designated
57 time, the character is passed through; otherwise, the
58 function key value is returned. For this reason, many
59 terminals experience a delay between the time a user
61 The <STRONG>ungetch</STRONG> routine places <EM>ch</EM> back onto the input queue to
62 be returned by the next call to <STRONG>wgetch</STRONG>. Note that there
63 is, in effect, just one input queue for all windows.
66 <STRONG>Function</STRONG> <STRONG>Keys</STRONG>
67 The following function keys, defined in <STRONG><curses.h></STRONG>, might
68 be returned by <STRONG>getch</STRONG> if <STRONG>keypad</STRONG> has been enabled. Note
69 that not all of these are necessarily supported on any
72 center tab(/) ; l l l l . <EM>Name</EM>/<EM>Key</EM> <EM>name</EM>
74 KEY_BREAK/Break key KEY_DOWN/The four arrow keys ...
75 KEY_UP KEY_LEFT KEY_RIGHT KEY_HOME/Home key (upward+left
76 arrow) KEY_BACKSPACE/Backspace KEY_F0/T{ Function keys;
77 space for 64 keys is reserved. T} KEY_F(<EM>n</EM>)/T{ For 0 <= <EM>n</EM>
78 <= 63 T} KEY_DL/Delete line KEY_IL/Insert line
79 KEY_DC/Delete character KEY_IC/Insert char or enter insert
80 mode KEY_EIC/Exit insert char mode KEY_CLEAR/Clear screen
81 KEY_EOS/Clear to end of screen KEY_EOL/Clear to end of
82 line KEY_SF/Scroll 1 line forward KEY_SR/Scroll 1 line
83 backward (reverse) KEY_NPAGE/Next page KEY_PPAGE/Previous
84 page KEY_STAB/Set tab KEY_CTAB/Clear tab KEY_CATAB/Clear
85 all tabs KEY_ENTER/Enter or send KEY_SRESET/Soft (partial)
86 reset KEY_RESET/Reset or hard reset KEY_PRINT/Print or
87 copy KEY_LL/Home down or bottom (lower left).
88 KEY_A1/Upper left of keypad KEY_A3/Upper right of keypad
89 KEY_B2/Center of keypad KEY_C1/Lower left of keypad
90 KEY_C3/Lower right of keypad KEY_BTAB/Back tab key
91 KEY_BEG/Beg(inning) key KEY_CANCEL/Cancel key
92 KEY_CLOSE/Close key KEY_COMMAND/Cmd (command) key
93 KEY_COPY/Copy key KEY_CREATE/Create key KEY_END/End key
94 KEY_EXIT/Exit key KEY_FIND/Find key KEY_HELP/Help key
95 KEY_MARK/Mark key KEY_MESSAGE/Message key KEY_MOVE/Move
96 key KEY_NEXT/Next object key KEY_OPEN/Open key
97 KEY_OPTIONS/Options key KEY_PREVIOUS/Previous object key
98 KEY_REDO/Redo key KEY_REFERENCE/Ref(erence) key
99 KEY_REFRESH/Refresh key KEY_REPLACE/Replace key
100 KEY_RESTART/Restart key KEY_RESUME/Resume key
101 KEY_SAVE/Save key KEY_SBEG/Shifted beginning key KEY_SCAN-
102 CEL/Shifted cancel key KEY_SCOMMAND/Shifted command key
103 KEY_SCOPY/Shifted copy key KEY_SCREATE/Shifted create key
104 KEY_SDC/Shifted delete char key KEY_SDL/Shifted delete
105 line key KEY_SELECT/Select key KEY_SEND/Shifted end key
106 KEY_SEOL/Shifted clear line key KEY_SEXIT/Shifted exit key
107 KEY_SFIND/Shifted find key KEY_SHELP/Shifted help key
108 KEY_SHOME/Shifted home key KEY_SIC/Shifted input key
109 KEY_SLEFT/Shifted left arrow key KEY_SMESSAGE/Shifted mes-
110 sage key KEY_SMOVE/Shifted move key KEY_SNEXT/Shifted next
111 key KEY_SOPTIONS/Shifted options key KEY_SPREVIOUS/Shifted
112 KEY_SRIGHT/Shifted right arrow KEY_SRSUME/Shifted resume
113 key KEY_SSAVE/Shifted save key KEY_SSUSPEND/Shifted sus-
114 pend key KEY_SUNDO/Shifted undo key KEY_SUSPEND/Suspend
115 key KEY_UNDO/Undo key
117 Keypad is arranged like this:
119 center allbox tab(/) ; c c c . <STRONG>A1</STRONG>/<STRONG>up</STRONG>/<STRONG>A3</STRONG> <STRONG>left</STRONG>/<STRONG>B2</STRONG>/<STRONG>right</STRONG>
120 <STRONG>C1</STRONG>/<STRONG>down</STRONG>/<STRONG>C3</STRONG>
122 The <STRONG>has_key</STRONG> routine takes a key value from the above list,
123 and returns TRUE or FALSE according as the current termi-
124 nal type recognizes a key with that value.
129 <H2>RETURN VALUE</H2><PRE>
130 All routines return the integer <STRONG>ERR</STRONG> upon failure and an
131 integer value other than <STRONG>ERR</STRONG> (<STRONG>OK</STRONG> in the case of ungetch())
132 upon successful completion.
137 Use of the escape key by a programmer for a single charac-
138 ter function is discouraged, as it will cause a delay of
139 up to one second while the keypad code looks for a follow-
140 ing function-key sequence.
142 When using <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, or <STRONG>mvwgetch</STRONG>, nocbreak
143 mode (<STRONG>nocbreak</STRONG>) and echo mode (<STRONG>echo</STRONG>) should not be used at
144 the same time. Depending on the state of the tty driver
145 when each character is typed, the program may produce
148 Note that <STRONG>getch</STRONG>, <STRONG>mvgetch</STRONG>, and <STRONG>mvwgetch</STRONG> may be macros.
150 Historically, the set of keypad macros was largely defined
151 by the extremely function-key-rich keyboard of the AT&T
152 7300, aka 3B1, aka Safari 4. Modern personal computers
153 usually have only a small subset of these. IBM PC-style
154 consoles typically support little more than <STRONG>KEY_UP</STRONG>,
155 <STRONG>KEY_DOWN</STRONG>, <STRONG>KEY_LEFT</STRONG>, <STRONG>KEY_RIGHT</STRONG>, <STRONG>KEY_HOME</STRONG>, <STRONG>KEY_END</STRONG>,
156 <STRONG>KEY_NPAGE</STRONG>, <STRONG>KEY_PPAGE</STRONG>, and function keys 1 through 12. The
157 Ins key is usually mapped to <STRONG>KEY_IC</STRONG>.
161 <H2>PORTABILITY</H2><PRE>
162 The *get* functions are described in the XSI Curses stan-
163 dard, Issue 4. They read single-byte characters only.
164 The standard specifies that they return <STRONG>ERR</STRONG> on failure,
165 but specifies no error conditions.
167 The echo behavior of these functions on input of <STRONG>KEY_</STRONG> or
168 backspace characters was not specified in the SVr4 docu-
169 mentation. This description is adopted from the XSI
170 dled signals is unspecified in the SVr4 and XSI Curses
171 documentation. Under historical curses implementations,
172 it varied depending on whether the operating system's
173 implementation of handled signal receipt interrupts a
174 <STRONG><A HREF="read.2.html">read(2)</A></STRONG> call in progress or not, and also (in some imple-
175 mentations) depending on whether an input timeout or non-
176 blocking mode hsd been set.
178 Programmers concerned about portability should be prepared
179 for either of two cases: (a) signal receipt does not
180 interrupt <STRONG>getch</STRONG>; (b) signal receipt interrupts <STRONG>getch</STRONG> and
181 causes it to return ERR with <STRONG>errno</STRONG> set to <STRONG>EINTR</STRONG>. Under
182 the <STRONG>ncurses</STRONG> implementation, handled signals never inter-
183 rupt <STRONG>getch</STRONG>.
185 The <STRONG>has_key</STRONG> function is unique to <STRONG>ncurses</STRONG>. We recommend
186 that any code using it be conditionalized on the NCURSES
191 <H2>SEE ALSO</H2><PRE>
192 <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_move.3x.html">curs_move(3X)</A></STRONG>,
193 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3X)</A></STRONG>.