https://invisible-island.net/ncurses/man/
curs_instr(3x) Library calls curs_instr(3x)
instr, winstr, mvinstr, mvwinstr, innstr, winnstr, mvinnstr, mvwinnstr
- get a string from a curses window
#include <curses.h>
int instr(char * str);
int winstr(WINDOW * win, char * str);
int mvinstr(int y, int x, char * str);
int mvwinstr(WINDOW * win, int y, int x, char * str);
int innstr(char * str, int n);
int winnstr(WINDOW * win, char * str, int n);
int mvinnstr(int y, int x, char * str, int n);
int mvwinnstr(WINDOW * win, int y, int x, char * str, int n);
winstr extracts a string from a curses window win, starting at the
cursor and stopping at the end of the line, and stores it in str,
terminating it with a null character and omitting any attributes and
color pair identifier that curses associates with each character.
winnstr does the same, but copies at most n characters from win. A
negative n implies no limit; winnstr then works like winstr.
ncurses(3x) describes the variants of these functions.
These functions return the count of characters copied from win to str
(not including the null terminator), or ERR upon failure.
In ncurses, these functions fail if
o the curses screen has not been initialized,
o (for functions taking a WINDOW pointer argument) win is a null
pointer, or
o str is a null pointer.
Functions prefixed with "mv" first perform cursor movement and fail if
the position (y, x) is outside the window boundaries.
All of these functions except winnstr may be implemented as macros.
Reading a line that overflows the array pointed to by str with and its
variants causes undefined results. Instead, use the n-infixed
functions with a positive n argument no larger than the size of the
buffer backing str.
innstr, winnstr, mvinnstr, and mvwinnstr's acceptance of negative n
values is an ncurses extension.
Applications employing ncurses extensions should condition their use on
the visibility of the NCURSES_VERSION preprocessor macro.
X/Open Curses Issue 4 describes these functions. It specifies no error
conditions for them.
X/Open Curses Issues 4 and 7 both state that instr, winstr, mvinstr,
and mvwinstr return OK rather than a character count. This is likely
an erratum.
o SVr3.1 and SVr4 implemented winstr as a wrapper around winnstr,
returning the latter's return value. X/Open Curses's specification
thus may have been an editorial solecism copied from System V's
documentation (see below) by X/Open, rather than an intentional
change.
o ncurses retains compatibility with System V curses behavior.
SVr4 describes a successful return value only as "an integer value
other than ERR".
SVr4 does not document whether n counts the null terminator that these
functions write to str.
SVr3.1 (1987) introduced these functions.
curs_inwstr(3x) describes comparable functions of the ncurses library
in its wide-character configuration (ncursesw).
curses(3x), curs_inch(3x), curs_inchstr(3x)
ncurses 6.5 2025-10-20 curs_instr(3x)