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30 * @Id: curs_getstr.3x,v 1.59 2024/05/11 20:39:53 tom Exp @
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42 <H1 class="no-header">curs_getstr 3x 2024-05-11 ncurses 6.5 Library calls</H1>
44 <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG>
49 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
50 <STRONG>getstr</STRONG>, <STRONG>getnstr</STRONG>, <STRONG>wgetstr</STRONG>, <STRONG>wgetnstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetstr</STRONG>,
51 <STRONG>mvwgetnstr</STRONG> - accept character strings 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>getstr(char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG>
58 <STRONG>int</STRONG> <STRONG>getnstr(char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG>
59 <STRONG>int</STRONG> <STRONG>wgetstr(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG>
60 <STRONG>int</STRONG> <STRONG>wgetnstr(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG>
62 <STRONG>int</STRONG> <STRONG>mvgetstr(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG>
63 <STRONG>int</STRONG> <STRONG>mvwgetstr(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>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG>
64 <STRONG>int</STRONG> <STRONG>mvgetnstr(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG>
65 <STRONG>int</STRONG> <STRONG>mvwgetnstr(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>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG>
68 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
69 The function <STRONG>wgetnstr</STRONG> is equivalent to a series of calls to <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>,
70 until a newline or carriage return terminates the series:
72 <STRONG>o</STRONG> The terminating character is not included in the returned string.
74 <STRONG>o</STRONG> In all instances, the end of the string is terminated by a NUL.
76 <STRONG>o</STRONG> The function stores the result in the area pointed to by the <EM>str</EM>
79 <STRONG>o</STRONG> The function reads at most <EM>n</EM> characters, thus preventing a possible
80 overflow of the input buffer.
82 Any attempt to enter more characters (other than the terminating
83 newline or carriage return) causes a beep.
85 Function keys also cause a beep and are ignored.
87 The user's <EM>erase</EM> and <EM>kill</EM> characters are interpreted:
89 <STRONG>o</STRONG> The <EM>erase</EM> character (e.g., <STRONG>^H</STRONG>) erases the character at the end of
90 the buffer, moving the cursor to the left.
92 If <EM>keypad</EM> mode is on for the window, <STRONG>KEY_LEFT</STRONG> and <STRONG>KEY_BACKSPACE</STRONG> are
93 both considered equivalent to the user's <EM>erase</EM> character.
95 <STRONG>o</STRONG> The <EM>kill</EM> character (e.g., <STRONG>^U</STRONG>) erases the entire buffer, leaving the
96 cursor at the beginning of the buffer.
98 Characters input are echoed only if <STRONG>echo</STRONG> is currently on. In that
99 case, backspace is echoed as deletion of the previous character
100 (typically a left motion).
102 The <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetnstr</STRONG>, and <STRONG>wgetnstr</STRONG> functions are
103 identical to the <STRONG>getstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvwgetstr</STRONG>, and <STRONG>wgetstr</STRONG> functions,
104 respectively, except that the <STRONG>*n*</STRONG> versions read at most <EM>n</EM> characters,
105 letting the application prevent overflow of the input buffer.
108 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
109 All of these functions return the integer <STRONG>OK</STRONG> upon successful
110 completion. (SVr4 specifies only "an integer value other than <STRONG>ERR</STRONG>") If
111 unsuccessful, they return <STRONG>ERR</STRONG>.
113 X/Open defines no error conditions.
115 In this implementation, these functions return an error
117 <STRONG>o</STRONG> if the window pointer is null,
119 <STRONG>o</STRONG> if its timeout expires without having any data, or
121 <STRONG>o</STRONG> if the associated call to <STRONG>wgetch</STRONG> failed.
123 This implementation provides an extension as well. If a <STRONG>SIGWINCH</STRONG>
124 interrupts the function, it will return <STRONG>KEY_RESIZE</STRONG> rather than <STRONG>OK</STRONG> or
125 <STRONG>ERR</STRONG>.
127 Functions prefixed with "mv" first perform cursor movement and fail if
128 the position (<EM>y</EM>, <EM>x</EM>) is outside the window boundaries.
131 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
132 Any of these functions other than <STRONG>wgetnstr</STRONG> may be macros.
134 Using <STRONG>getstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvwgetstr</STRONG>, or <STRONG>wgetstr</STRONG> to read a line that
135 overflows the array pointed to by <STRONG>str</STRONG> causes undefined results. The
136 use of <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetnstr</STRONG>, or <STRONG>wgetnstr</STRONG>, respectively, is
140 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
141 These functions are described in The Single Unix Specification, Version
142 2. No error conditions are defined.
144 This implementation returns <STRONG>ERR</STRONG> if the window pointer is null, or if
145 the lower-level <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> call returns an <STRONG>ERR</STRONG>.
147 SVr3 and early SVr4 curses implementations did not reject function
148 keys; the SVr4.0 documentation claimed that "special keys" (such as
149 function keys, "home" key, "clear" key, <EM>etc</EM>.) are "interpreted",
150 without giving details. It lied. In fact, the "character" value
151 appended to the string by those implementations was predictable but not
152 useful (being, in fact, the low-order eight bits of the key's KEY_
155 The functions <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, and <STRONG>mvwgetnstr</STRONG> were present but not
158 X/Open Curses, Issue 5 (2007) stated that these functions "read at most
159 <EM>n</EM> bytes" but did not state whether the terminating NUL counted toward
160 that limit. X/Open Curses, Issue 7 (2009) changed that to say they
161 "read at most <EM>n</EM>-1 bytes" to allow for the terminating NUL. As of 2018,
162 some implementations count it, some do not:
164 <STRONG>o</STRONG> <EM>ncurses</EM> 6.1 and PDCurses do not count the NUL in the given limit,
167 <STRONG>o</STRONG> Solaris SVr4 and NetBSD curses count the NUL as part of the limit.
169 <STRONG>o</STRONG> Solaris xcurses provides both: its wide-character <STRONG>wget_nstr</STRONG>
170 reserves a NUL, but its <STRONG>wgetnstr</STRONG> does not count the NUL
173 In SVr4 curses, a negative value of <EM>n</EM> tells <STRONG>wgetnstr</STRONG> to assume that the
174 caller's buffer is large enough to hold the result, i.e., to act like
175 <STRONG>wgetstr</STRONG>. X/Open Curses does not mention this (or anything related to
176 negative or zero values of <EM>n</EM>), however most implementations use the
177 feature, with different limits:
179 <STRONG>o</STRONG> Solaris SVr4 curses and PDCurses limit the result to 255 bytes.
180 Other Unix systems than Solaris are likely to use the same limit.
182 <STRONG>o</STRONG> Solaris xcurses limits the result to <STRONG>LINE_MAX</STRONG> bytes.
184 <STRONG>o</STRONG> NetBSD 7 assumes no particular limit for the result from <STRONG>wgetstr</STRONG>.
185 However, it limits the <STRONG>wgetnstr</STRONG> parameter <EM>n</EM> to ensure that it is
188 A comment in NetBSD's source code states that this is specified in
191 <STRONG>o</STRONG> <EM>ncurses</EM> (before 6.2) assumes no particular limit for the result
192 from <STRONG>wgetstr</STRONG>, and treats the <EM>n</EM> parameter of <STRONG>wgetnstr</STRONG> like SVr4
195 <STRONG>o</STRONG> <EM>ncurses</EM> 6.2 uses <STRONG>LINE_MAX</STRONG>, or a larger (system-dependent) value
196 which the <STRONG>sysconf</STRONG> function may provide. If neither <STRONG>LINE_MAX</STRONG> or
197 <STRONG>sysconf</STRONG> is available, <EM>ncurses</EM> uses the POSIX value for <STRONG>LINE_MAX</STRONG> (a
198 2048 byte limit). In either case, it reserves a byte for the
201 Although <STRONG>getnstr</STRONG> is equivalent to a series of calls to <STRONG>getch</STRONG>, it also
202 makes changes to the curses modes to allow simple editing of the input
205 <STRONG>o</STRONG> <STRONG>getnstr</STRONG> saves the current value of the <STRONG>nl</STRONG>, <STRONG>echo</STRONG>, <STRONG>raw</STRONG> and <STRONG>cbreak</STRONG>
206 modes, and sets <STRONG>nl</STRONG>, <STRONG>noecho</STRONG>, <STRONG>noraw</STRONG>, and <STRONG>cbreak</STRONG>.
208 <STRONG>getnstr</STRONG> handles the echoing of characters, rather than relying on
209 the caller to set an appropriate mode.
211 <STRONG>o</STRONG> It also obtains the <EM>erase</EM> and <EM>kill</EM> characters from <STRONG>erasechar</STRONG> and
212 <STRONG>killchar</STRONG>, respectively.
214 <STRONG>o</STRONG> On return, <STRONG>getnstr</STRONG> restores the modes to their previous values.
216 Other implementations differ in their treatment of special characters:
218 <STRONG>o</STRONG> While they may set the <EM>echo</EM> mode, other implementations do not
219 modify the <EM>raw</EM> mode, They may take the <EM>cbreak</EM> mode set by the
220 caller into account when deciding whether to handle echoing within
221 <STRONG>getnstr</STRONG> or as a side-effect of the <STRONG>getch</STRONG> calls.
223 <STRONG>o</STRONG> The original <EM>ncurses</EM> (as <EM>pcurses</EM> in 1986) set <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> when
224 accepting input for <STRONG>getnstr</STRONG>. That may have been done to make
225 function- and cursor-keys work; it is not necessary with <EM>ncurses</EM>.
227 Since 1995, <EM>ncurses</EM> has provided signal handlers for INTR and QUIT
228 (e.g., <STRONG>^C</STRONG> or <STRONG>^\</STRONG>). With the <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> settings, those may
229 catch a signal and stop the program, where other implementations
230 allow one to enter those characters in the buffer.
232 <STRONG>o</STRONG> Starting in 2021 (<EM>ncurses</EM> 6.3), <STRONG>getnstr</STRONG> sets <STRONG>raw</STRONG>, rather than <STRONG>noraw</STRONG>
233 and <STRONG>cbreak</STRONG> for better compatibility with SVr4-curses, e.g.,
234 allowing one to enter a <STRONG>^C</STRONG> into the buffer.
237 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
238 <STRONG><A HREF="curs_get_wstr.3x.html">curs_get_wstr(3x)</A></STRONG> describes comparable functions of the <EM>ncurses</EM> library
239 in its wide-character configuration (<EM>ncursesw</EM>).
241 <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>, <STRONG><A HREF="curs_termattrs.3x.html">curs_termattrs(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>
245 ncurses 6.5 2024-05-11 <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG>
249 <li><a href="#h2-NAME">NAME</a></li>
250 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
251 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
252 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
253 <li><a href="#h2-NOTES">NOTES</a></li>
254 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
255 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>