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28 .\"
29 .\" $Id: curs_get_wch.3x,v 1.7 2010/08/14 23:31:42 tom Exp $
30 .TH curs_get_wch 3 ""
31 .SH NAME
32 \fBget_wch\fR,
33 \fBwget_wch\fR,
34 \fBmvget_wch\fR,
35 \fBmvwget_wch\fR,
36 \fBunget_wch\fR \- get (or push back) a wide character from curses terminal keyboard
37 .SH SYNOPSIS
38 \fB#include <curses.h>\fR
39 .sp
40 \fBint get_wch(wint_t *\fR\fIwch\fR\fB);\fR
41 .br
42 \fBint wget_wch(WINDOW *\fR\fIwin\fR\fB, wint_t *\fR\fIwch\fR\fB);\fR
43 .br
44 \fBint mvget_wch(int \fR\fIy\fR\fB, int \fR\fIx\fR\fB, wint_t *\fR\fIwch\fR\fB);\fR
45 .br
46 \fBint mvwget_wch(WINDOW *\fR\fIwin\fR\fB, int \fR\fIy\fR\fB, int \fR\fIx\fR\fB, wint_t *\fR\fIwch\fR\fB);\fR
47 .br
48 \fBint unget_wch(const wchar_t \fR\fIwch\fR\fB);\fR
49 .SH DESCRIPTION
50 The
51 \fBget_wch\fR,
52 \fBwget_wch\fR,
53 \fBmvget_wch\fR, and
54 \fBmvwget_wch\fR
55 functions read a character
56 from the terminal associated with the current or specified window.
57 In no-delay mode,
58 if no input is waiting, the value \fBERR\fR is returned.
59 In delay mode,
60 the program waits until the system passes text through to the program.
61 Depending on the setting of \fBcbreak\fR,
62 this is after one character (cbreak mode),
63 or after the first newline (nocbreak mode).
64 In half-delay mode,
65 the program waits until the user types a character or the specified
66 timeout interval has elapsed.
67 .PP
68 Unless \fBnoecho\fR has been set,
69 these routines echo the character into the designated window.
70 .PP
71 If the window is not a pad and has been moved or modified since the
72 last call to \fBwrefresh\fR,
73 \fBwrefresh\fR will be called before another character is read.
74 .PP
75 If \fBkeypad\fR is enabled,
76 these functions respond to
77 the pressing of a function key by setting the object pointed to by
78 \fIwch\fR
79 to the corresponding
80 \fBKEY_\fR
81 value defined
82 in
83 \fB<curses.h>\fR
84 and returning
85 \fBKEY_CODE_YES\fR.
86 If a character (such as escape) that could be the
87 beginning of a function key is received, curses sets a timer.
88 If the remainder
89 of the sequence does arrive within the designated time, curses passes through
90 the character; otherwise, curses returns the function key value.
91 For this
92 reason, many terminals experience a delay between the time a user presses
93 the escape key and the time the escape is returned to the program.
94 .PP
95 The
96 \fBunget_wch\fR
97 function pushes the wide character
98 \fIwch\fR
99 back onto the head of the input queue, so the wide character
100 is returned by the next call to
101 \fBget_wch\fR.
102 The pushback of
103 one character is guaranteed.
104 If the program calls
105 \fBunget_wch\fR
106 too many times without an intervening call to
107 \fBget_wch\fR,
108 the operation may fail.
109 .SH NOTES
110 The header file
111 \fB<curses.h>\fR
112 automatically
113 includes the header file
114 \fB<stdio.h>\fR.
115 .PP
116 Applications should not define the escape key by itself as a single-character
117 function.
118 .PP
119 When using
120 \fBget_wch\fR,
121 \fBwget_wch\fR,
122 \fBmvget_wch\fR, or
123 \fBmvwget_wch\fR, applications should
124 not use
125 \fBnocbreak\fR
126 mode and
127 \fBecho\fR
128 mode
129 at the same time.
130 Depending on the state of the tty driver when each character
131 is typed, the program may produce undesirable results.
132 .PP
133 All functions except \fBwget_wch\fR and \fBunget_wch\fR
134 may be macros.
135 .SH RETURN VALUES
136 When
137 \fBget_wch\fR,
138 \fBwget_wch\fR,
139 \fBmvget_wch\fR, and
140 \fBmvwget_wch\fR
141 functions successfully
142 report the pressing of a function key, they return
143 \fBKEY_CODE_YES\fR.
144 When they successfully report a wide character, they return
145 \fBOK\fR.
146 Otherwise, they return
147 \fBERR\fR.
148 .PP
149 Upon successful completion,
150 \fBunget_wch\fR
151 returns
152 \fBOK\fR.
153 Otherwise, the function returns
154 \fBERR\fR.
155 .PP
156 Functions with a "mv" prefix first perform a cursor movement using
157 \fBwmove\fP, and return an error if the position is outside the window,
158 or if the window pointer is null.
159 .SH SEE ALSO
160 \fBcurses\fR(3),
161 \fBcurs_getch\fR(3),
162 \fBcurs_ins_wch\fR(3),
163 \fBcurs_inopts\fR(3),
164 \fBcurs_move\fR(3),
165 \fBcurs_refresh\fR(3)