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30 * @Id: curs_getstr.3x,v 1.37 2022/02/12 20:07:29 tom Exp @
31 * X/Open says also until EOf
32 * X/Open says then an EOS is added to the result
33 * X/Open doesn't mention n<0
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45 <H1 class="no-header">curs_getstr 3x 2022-02-12 ncurses 6.4 Library calls</H1>
47 <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>
52 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
53 <STRONG>getstr</STRONG>, <STRONG>getnstr</STRONG>, <STRONG>wgetstr</STRONG>, <STRONG>wgetnstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetstr</STRONG>,
54 <STRONG>mvwgetnstr</STRONG> - accept character strings from <STRONG>curses</STRONG> terminal keyboard
57 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
58 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
60 <STRONG>int</STRONG> <STRONG>getstr(char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG>
61 <STRONG>int</STRONG> <STRONG>getnstr(char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG>
62 <STRONG>int</STRONG> <STRONG>wgetstr(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG>
63 <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>
65 <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>
66 <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>
67 <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>
68 <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>
71 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
72 The function <STRONG>getstr</STRONG> is equivalent to a series of calls to <STRONG>getch</STRONG>, until
73 a newline or carriage return is received (the terminating character is
74 not included in the returned string). The resulting value is placed in
75 the area pointed to by the character pointer <EM>str</EM>, followed by a NUL.
77 The <STRONG>getnstr</STRONG> function reads from the <EM>stdscr</EM> default window. The other
78 functions, such as <STRONG>wgetnstr</STRONG>, read from the window given as a parameter.
80 <STRONG>getnstr</STRONG> reads at most <EM>n</EM> characters, thus preventing a possible overflow
81 of the input buffer. Any attempt to enter more characters (other than
82 the terminating newline or carriage return) causes a beep. Function
83 keys also cause a beep and are ignored.
85 The user's <EM>erase</EM> and <EM>kill</EM> characters are interpreted:
87 <STRONG>o</STRONG> The <EM>erase</EM> character (e.g., <STRONG>^H</STRONG>) erases the character at the end of
88 the buffer, moving the cursor to the left.
90 If <EM>keypad</EM> mode is on for the window, <STRONG>KEY_LEFT</STRONG> and <STRONG>KEY_BACKSPACE</STRONG> are
91 both considered equivalent to the user's erase character.
93 <STRONG>o</STRONG> The <EM>kill</EM> character (e.g., <STRONG>^U</STRONG>) erases the entire buffer, leaving the
94 cursor at the beginning of the buffer.
96 Characters input are echoed only if <STRONG>echo</STRONG> is currently on. In that
97 case, backspace is echoed as deletion of the previous character (typi-
101 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
102 All routines return the integer <STRONG>ERR</STRONG> upon failure and an <STRONG>OK</STRONG> (SVr4 speci-
103 fies only "an integer value other than <STRONG>ERR</STRONG>") upon successful comple-
106 X/Open defines no error conditions.
108 In this implementation, these functions return an error if the window
109 pointer is null, or if its timeout expires without having any data.
111 This implementation provides an extension as well. If a <STRONG>SIGWINCH</STRONG> in-
112 terrupts the function, it will return <STRONG>KEY_RESIZE</STRONG> rather than <STRONG>OK</STRONG> or <STRONG>ERR</STRONG>.
114 Functions with a "mv" prefix first perform a cursor movement using
115 <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
116 the window pointer is null.
119 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
120 Note that <STRONG>getstr</STRONG>, <STRONG>mvgetstr</STRONG>, and <STRONG>mvwgetstr</STRONG> may be macros.
123 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
124 These functions are described in the XSI Curses standard, Issue 4.
125 They read single-byte characters only. The standard does not define
126 any error conditions. This implementation returns <STRONG>ERR</STRONG> if the window
127 pointer is null, or if the lower-level <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> call returns an <STRONG>ERR</STRONG>.
129 SVr3 and early SVr4 curses implementations did not reject function
130 keys; the SVr4.0 documentation claimed that "special keys" (such as
131 function keys, "home" key, "clear" key, <EM>etc</EM>.) are "interpreted", with-
132 out giving details. It lied. In fact, the "character" value appended
133 to the string by those implementations was predictable but not useful
134 (being, in fact, the low-order eight bits of the key's KEY_ value).
136 The functions <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, and <STRONG>mvwgetnstr</STRONG> were present but not
139 X/Open Curses, Issue 5 (2007) stated that these functions "read at most
140 <EM>n</EM> bytes" but did not state whether the terminating NUL is counted in
141 that limit. X/Open Curses, Issue 7 (2009) changed that to say they
142 "read at most <EM>n</EM>-1 bytes" to allow for the terminating NUL. As of 2018,
143 some implementations do, some do not count it:
145 <STRONG>o</STRONG> ncurses 6.1 and PDCurses do not count the NUL in the given limit,
148 <STRONG>o</STRONG> Solaris SVr4 and NetBSD curses count the NUL as part of the limit.
150 <STRONG>o</STRONG> Solaris xcurses provides both: its wide-character <STRONG>wget_nstr</STRONG> re-
151 serves a NUL, but its <STRONG>wgetnstr</STRONG> does not count the NUL consistently.
153 In SVr4 curses, a negative value of <EM>n</EM> tells <STRONG>wgetnstr</STRONG> to assume that the
154 caller's buffer is large enough to hold the result, i.e., to act like
155 <STRONG>wgetstr</STRONG>. X/Open Curses does not mention this (or anything related to
156 negative or zero values of <EM>n</EM>), however most implementations use the
157 feature, with different limits:
159 <STRONG>o</STRONG> Solaris SVr4 curses and PDCurses limit the result to 255 bytes.
160 Other Unix systems than Solaris are likely to use the same limit.
162 <STRONG>o</STRONG> Solaris xcurses limits the result to <STRONG>LINE_MAX</STRONG> bytes.
164 <STRONG>o</STRONG> NetBSD 7 assumes no particular limit for the result from <STRONG>wgetstr</STRONG>.
165 However, it limits the <STRONG>wgetnstr</STRONG> parameter <EM>n</EM> to ensure that it is
168 A comment in NetBSD's source code states that this is specified in
171 <STRONG>o</STRONG> ncurses (before 6.2) assumes no particular limit for the result
172 from <STRONG>wgetstr</STRONG>, and treats the <EM>n</EM> parameter of <STRONG>wgetnstr</STRONG> like SVr4
175 <STRONG>o</STRONG> ncurses 6.2 uses <STRONG>LINE_MAX</STRONG>, or a larger (system-dependent) value
176 which the <STRONG>sysconf</STRONG> function may provide. If neither <STRONG>LINE_MAX</STRONG> or
177 <STRONG>sysconf</STRONG> is available, ncurses uses the POSIX value for <STRONG>LINE_MAX</STRONG> (a
178 2048 byte limit). In either case, it reserves a byte for the ter-
181 Although <STRONG>getnstr</STRONG> is equivalent to a series of calls to <STRONG>getch</STRONG>, it also
182 makes changes to the curses modes to allow simple editing of the input
185 <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>
186 modes, and sets <STRONG>nl</STRONG>, <STRONG>noecho</STRONG>, <STRONG>noraw</STRONG>, and <STRONG>cbreak</STRONG>.
188 <STRONG>getnstr</STRONG> handles the echoing of characters, rather than relying on
189 the caller to set an appropriate mode.
191 <STRONG>o</STRONG> It also obtains the <EM>erase</EM> and <EM>kill</EM> characters from <STRONG>erasechar</STRONG> and
192 <STRONG>killchar</STRONG>, respectively.
194 <STRONG>o</STRONG> On return, <STRONG>getnstr</STRONG> restores the modes to their previous values.
196 Other implementations differ in their treatment of special characters:
198 <STRONG>o</STRONG> While they may set the <EM>echo</EM> mode, other implementations do not mod-
199 ify the <EM>raw</EM> mode, They may take the <EM>cbreak</EM> mode set by the caller
200 into account when deciding whether to handle echoing within <STRONG>getnstr</STRONG>
201 or as a side-effect of the <STRONG>getch</STRONG> calls.
203 <STRONG>o</STRONG> The original ncurses (as <EM>pcurses</EM> in 1986) set <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> when
204 accepting input for <STRONG>getnstr</STRONG>. That may have been done to make func-
205 tion- and cursor-keys work; it is not necessary with ncurses.
207 Since 1995, ncurses has provided signal handlers for INTR and QUIT
208 (e.g., <STRONG>^C</STRONG> or <STRONG>^\</STRONG>). With the <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> settings, those may
209 catch a signal and stop the program, where other implementations
210 allow one to enter those characters in the buffer.
212 <STRONG>o</STRONG> Starting in 2021 (ncurses 6.3), <STRONG>getnstr</STRONG> sets <STRONG>raw</STRONG>, rather than <STRONG>noraw</STRONG>
213 and <STRONG>cbreak</STRONG> for better compatibility with SVr4-curses, e.g., allow-
214 ing one to enter a <STRONG>^C</STRONG> into the buffer.
217 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
218 <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>.
222 ncurses 6.4 2022-02-12 <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG>
226 <li><a href="#h2-NAME">NAME</a></li>
227 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
228 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
229 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
230 <li><a href="#h2-NOTES">NOTES</a></li>
231 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
232 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>