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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | PORTABILITY | SEE ALSO | COLOPHON |
curs_getstr(3X) curs_getstr(3X)
getstr, getnstr, wgetstr, wgetnstr, mvgetstr, mvgetnstr, mvwgetstr,
mvwgetnstr - accept character strings from curses terminal keyboard
#include <curses.h>
int getstr(char *str);
int getnstr(char *str, int n);
int wgetstr(WINDOW *win, char *str);
int wgetnstr(WINDOW *win, char *str, int n);
int mvgetstr(int y, int x, char *str);
int mvwgetstr(WINDOW *win, int y, int x, char *str);
int mvgetnstr(int y, int x, char *str, int n);
int mvwgetnstr(WINDOW *, int y, int x, char *str, int n);
The function getstr is equivalent to a series of calls to getch,
until a newline or carriage return is received (the terminating
character is not included in the returned string). The resulting
value is placed in the area pointed to by the character pointer str,
followed by a NUL.
wgetnstr reads at most n 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 getnstr
function reads from the stdscr default window.
The user's erase and kill characters are interpreted. If keypad mode
is on for the window, KEY_LEFT and KEY_BACKSPACE are both considered
equivalent to the user's kill character.
Characters input are echoed only if echo is currently on. In that
case, backspace is echoed as deletion of the previous character
(typically a left motion).
All routines return the integer ERR upon failure and an OK (SVr4
specifies only “an integer value other than ERR”) upon successful
completion.
X/Open defines no error conditions.
In this implementation, these functions return an error if the window
pointer is null, or if its timeout expires without having any data.
This implementation provides an extension as well. If a SIGWINCH
interrupts the function, it will return KEY_RESIZE rather than OK or
ERR.
Functions with a “mv” prefix first perform a cursor movement using
wmove, and return an error if the position is outside the window, or
if the window pointer is null.
Note that getstr, mvgetstr, and mvwgetstr may be macros.
These functions are described in the XSI Curses standard, Issue 4.
They read single-byte characters only. The standard does not define
any error conditions. This implementation returns ERR if the window
pointer is null, or if the lower-level wgetch(3X) call returns an
ERR.
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, etc.) 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 getnstr, mvgetnstr, and mvwgetnstr were present but not
documented in SVr4.
X/Open Curses, Issue 5 (2007) stated that these functions “read at
most n 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 n-1 bytes” to allow for the terminating NUL.
As of 2018, some implementations do, some do not count it:
· ncurses 6.1 and PDCurses do not count the NUL in the given limit,
while
· Solaris SVr4 and NetBSD curses count the NUL as part of the
limit.
· Solaris xcurses provides both: its wide-character wget_nstr
reserves a NUL, but its wgetnstr does not count the NUL
consistently.
In SVr4 curses, a negative value of n tells wgetnstr to assume that
the caller's buffer is large enough to hold the result, i.e., to act
like wgetstr. X/Open Curses does not mention this (or anything
related to negative or zero values of n), however most
implementations use the feature, with different limits:
· Solaris SVr4 curses and PDCurses limit the result to 255 bytes.
Other Unix systems than Solaris are likely to use the same limit.
· Solaris xcurses limits the result to LINE_MAX bytes.
· NetBSD 7 assumes no particular limit for the result from wgetstr.
However, it limits the wgetnstr parameter n to ensure that it is
greater than zero.
A comment in NetBSD's source code states that this is specified
in SUSv2.
· ncurses (before 6.2) assumes no particular limit for the result
from wgetstr, and treats the n parameter of wgetnstr like SVr4
curses.
· ncurses 6.2 uses LINE_MAX, or a larger (system-dependent) value
which the sysconf function may provide. If neither LINE_MAX or
sysconf is available, ncurses uses the POSIX value for LINE_MAX
(a 2048 byte limit). In either case, it reserves a byte for the
terminating NUL.
curses(3X), curs_getch(3X), curs_variables(3X).
This page is part of the ncurses (new curses) project. Information
about the project can be found at
⟨https://www.gnu.org/software/ncurses/ncurses.html⟩. If you have a
bug report for this manual page, send it to
bug-ncurses-request@gnu.org. This page was obtained from the
project's upstream Git mirror of the CVS repository
⟨git://ncurses.scripts.mit.edu/ncurses.git⟩ on 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2020-08-09.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not part
of the original manual page), send a mail to man-pages@man7.org
curs_getstr(3X)