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<H1 class="no-header">curs_getstr 3x 2024-04-20 ncurses 6.5 Library calls</H1>
<PRE>
<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>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>getstr</STRONG>, <STRONG>getnstr</STRONG>, <STRONG>wgetstr</STRONG>, <STRONG>wgetnstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetstr</STRONG>,
<STRONG>mvwgetnstr</STRONG> - accept character strings from <EM>curses</EM> terminal keyboard
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>int</STRONG> <STRONG>getstr(char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>getnstr(char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wgetstr(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG>
<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>
<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>
<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>
<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>
<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>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
The function <STRONG>wgetnstr</STRONG> is equivalent to a series of calls to <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>,
until a newline or carriage return terminates the series:
<STRONG>o</STRONG> The terminating character is not included in the returned string.
<STRONG>o</STRONG> In all instances, the end of the string is terminated by a NUL.
<STRONG>o</STRONG> The function stores the result in the area pointed to by the <EM>str</EM>
parameter.
<STRONG>o</STRONG> The function reads at most <EM>n</EM> characters, thus preventing a possible
overflow of the input buffer.
Any attempt to enter more characters (other than the terminating
newline or carriage return) causes a beep.
Function keys also cause a beep and are ignored.
The user's <EM>erase</EM> and <EM>kill</EM> characters are interpreted:
<STRONG>o</STRONG> The <EM>erase</EM> character (e.g., <STRONG>^H</STRONG>) erases the character at the end of
the buffer, moving the cursor to the left.
If <EM>keypad</EM> mode is on for the window, <STRONG>KEY_LEFT</STRONG> and <STRONG>KEY_BACKSPACE</STRONG> are
both considered equivalent to the user's <EM>erase</EM> character.
<STRONG>o</STRONG> The <EM>kill</EM> character (e.g., <STRONG>^U</STRONG>) erases the entire buffer, leaving the
cursor at the beginning of the buffer.
Characters input are echoed only if <STRONG>echo</STRONG> is currently on. In that
case, backspace is echoed as deletion of the previous character
(typically a left motion).
The <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetnstr</STRONG>, and <STRONG>wgetnstr</STRONG> functions are
identical to the <STRONG>getstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvwgetstr</STRONG>, and <STRONG>wgetstr</STRONG> functions,
respectively, except that the <STRONG>*n*</STRONG> versions read at most <EM>n</EM> characters,
letting the application prevent overflow of the input buffer.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
All of these functions return the integer <STRONG>OK</STRONG> upon successful
completion. (SVr4 specifies only "an integer value other than <STRONG>ERR</STRONG>") If
unsuccessful, they return <STRONG>ERR</STRONG>.
X/Open defines no error conditions.
In this implementation, these functions return an error
<STRONG>o</STRONG> if the window pointer is null,
<STRONG>o</STRONG> if its timeout expires without having any data, or
<STRONG>o</STRONG> if the associated call to <STRONG>wgetch</STRONG> failed.
This implementation provides an extension as well. If a <STRONG>SIGWINCH</STRONG>
interrupts the function, it will return <STRONG>KEY_RESIZE</STRONG> rather than <STRONG>OK</STRONG> or
<STRONG>ERR</STRONG>.
Functions prefixed with "mv" first perform cursor movement and fail if
the position (<EM>y</EM>, <EM>x</EM>) is outside the window boundaries.
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
Any of these functions other than <STRONG>wgetnstr</STRONG> may be macros.
Using <STRONG>getstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvwgetstr</STRONG>, or <STRONG>wgetstr</STRONG> to read a line that
overflows the array pointed to by <STRONG>str</STRONG> causes undefined results. The
use of <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetnstr</STRONG>, or <STRONG>wgetnstr</STRONG>, respectively, is
recommended.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
These functions are described in The Single Unix Specification, Version
2. No error conditions are defined.
This implementation returns <STRONG>ERR</STRONG> if the window 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>.
SVr3 and early SVr4 curses implementations did not reject function
keys; the SVr4.0 documentation claimed that "special keys" (such as
function keys, "home" key, "clear" key, <EM>etc</EM>.) are "interpreted",
without giving details. It lied. In fact, the "character" value
appended to the string by those implementations was predictable but not
useful (being, in fact, the low-order eight bits of the key's KEY_
value).
The functions <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, and <STRONG>mvwgetnstr</STRONG> were present but not
documented in SVr4.
X/Open Curses, Issue 5 (2007) stated that these functions "read at most
<EM>n</EM> bytes" but did not state whether the terminating NUL is counted in
that limit. X/Open Curses, Issue 7 (2009) changed that to say they
"read at most <EM>n</EM>-1 bytes" to allow for the terminating NUL. As of 2018,
some implementations count it, some do not:
<STRONG>o</STRONG> <EM>ncurses</EM> 6.1 and PDCurses do not count the NUL in the given limit,
while
<STRONG>o</STRONG> Solaris SVr4 and NetBSD curses count the NUL as part of the limit.
<STRONG>o</STRONG> Solaris xcurses provides both: its wide-character <STRONG>wget_nstr</STRONG>
reserves a NUL, but its <STRONG>wgetnstr</STRONG> does not count the NUL
consistently.
In SVr4 curses, a negative value of <EM>n</EM> tells <STRONG>wgetnstr</STRONG> to assume that the
caller's buffer is large enough to hold the result, i.e., to act like
<STRONG>wgetstr</STRONG>. X/Open Curses does not mention this (or anything related to
negative or zero values of <EM>n</EM>), however most implementations use the
feature, with different limits:
<STRONG>o</STRONG> Solaris SVr4 curses and PDCurses limit the result to 255 bytes.
Other Unix systems than Solaris are likely to use the same limit.
<STRONG>o</STRONG> Solaris xcurses limits the result to <STRONG>LINE_MAX</STRONG> bytes.
<STRONG>o</STRONG> NetBSD 7 assumes no particular limit for the result from <STRONG>wgetstr</STRONG>.
However, it limits the <STRONG>wgetnstr</STRONG> parameter <EM>n</EM> to ensure that it is
greater than zero.
A comment in NetBSD's source code states that this is specified in
SUSv2.
<STRONG>o</STRONG> <EM>ncurses</EM> (before 6.2) assumes no particular limit for the result
from <STRONG>wgetstr</STRONG>, and treats the <EM>n</EM> parameter of <STRONG>wgetnstr</STRONG> like SVr4
curses.
<STRONG>o</STRONG> <EM>ncurses</EM> 6.2 uses <STRONG>LINE_MAX</STRONG>, or a larger (system-dependent) value
which the <STRONG>sysconf</STRONG> function may provide. If neither <STRONG>LINE_MAX</STRONG> or
<STRONG>sysconf</STRONG> is available, <EM>ncurses</EM> uses the POSIX value for <STRONG>LINE_MAX</STRONG> (a
2048 byte limit). In either case, it reserves a byte for the
terminating NUL.
Although <STRONG>getnstr</STRONG> is equivalent to a series of calls to <STRONG>getch</STRONG>, it also
makes changes to the curses modes to allow simple editing of the input
buffer:
<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>
modes, and sets <STRONG>nl</STRONG>, <STRONG>noecho</STRONG>, <STRONG>noraw</STRONG>, and <STRONG>cbreak</STRONG>.
<STRONG>getnstr</STRONG> handles the echoing of characters, rather than relying on
the caller to set an appropriate mode.
<STRONG>o</STRONG> It also obtains the <EM>erase</EM> and <EM>kill</EM> characters from <STRONG>erasechar</STRONG> and
<STRONG>killchar</STRONG>, respectively.
<STRONG>o</STRONG> On return, <STRONG>getnstr</STRONG> restores the modes to their previous values.
Other implementations differ in their treatment of special characters:
<STRONG>o</STRONG> While they may set the <EM>echo</EM> mode, other implementations do not
modify the <EM>raw</EM> mode, They may take the <EM>cbreak</EM> mode set by the
caller into account when deciding whether to handle echoing within
<STRONG>getnstr</STRONG> or as a side-effect of the <STRONG>getch</STRONG> calls.
<STRONG>o</STRONG> The original <EM>ncurses</EM> (as <EM>pcurses</EM> in 1986) set <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> when
accepting input for <STRONG>getnstr</STRONG>. That may have been done to make
function- and cursor-keys work; it is not necessary with <EM>ncurses</EM>.
Since 1995, <EM>ncurses</EM> has provided signal handlers for INTR and QUIT
(e.g., <STRONG>^C</STRONG> or <STRONG>^\</STRONG>). With the <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> settings, those may
catch a signal and stop the program, where other implementations
allow one to enter those characters in the buffer.
<STRONG>o</STRONG> Starting in 2021 (<EM>ncurses</EM> 6.3), <STRONG>getnstr</STRONG> sets <STRONG>raw</STRONG>, rather than <STRONG>noraw</STRONG>
and <STRONG>cbreak</STRONG> for better compatibility with SVr4-curses, e.g.,
allowing one to enter a <STRONG>^C</STRONG> into the buffer.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="curs_get_wstr.3x.html">curs_get_wstr(3x)</A></STRONG> describes comparable functions of the <EM>ncurses</EM> library
in its wide-character configuration (<EM>ncursesw</EM>).
<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>
ncurses 6.5 2024-04-20 <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
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