https://invisible-island.net/ncurses/man/
curs_inwstr(3x) Library calls curs_inwstr(3x)
inwstr, winwstr, mvinwstr, mvwinwstr, innwstr, winnwstr, mvinnwstr,
mvwinnwstr - get a wide-character string from a curses window
#include <curses.h>
int inwstr(wchar_t * wstr);
int winwstr(WINDOW * win, wchar_t * wstr);
int mvinwstr(int y, int x, wchar_t * wstr);
int mvwinwstr(WINDOW * win, int y, int x, wchar_t * wstr);
int innwstr(wchar_t * wstr, int n);
int winnwstr(WINDOW * win, wchar_t * wstr, int n);
int mvinnwstr(int y, int x, wchar_t * wstr, int n);
int mvwinnwstr(WINDOW * win, int y, int x, wchar_t * wstr,
int n);
winwstr extracts a wide-character string from a curses window win,
starting at the cursor and stopping at the end of the line, and stores
it in wstr, terminating it with a wide null character and omitting any
attributes and color pair identifier that curses associates with each
character. winnwstr does the same, but copies at most n wide
characters from win. A negative n implies no limit; winnwstr then
works like winwstr. ncurses(3x) describes the variants of these
functions.
On successful operation, these functions return the count of wide
characters copied from win to wstr (not including the wide null
terminator), or ERR upon failure. innwstr, winnwstr, mvinnwstr, and
mvwinnwstr return ERR if n is insufficiently large to store a complete
wide character string. (Recall that a curses complex character can
contain multiple wide characters, some of which may be non-spacing.)
In ncurses, these functions return ERR if
o the curses screen has not been initialized,
o (for functions taking a WINDOW pointer argument) win is a null
pointer, or
o wstr 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 winnwstr may be implemented as macros.
Reading a line that overflows the array pointed to by wstr 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 wstr.
innwstr, winnwstr, mvinnwstr, and mvwinnwstr'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.
Notwithstanding the foregoing, X/Open Curses Issues 4 and 7 both state
that innwstr, winnwstr, mvinnwstr, and mvwinnwstr "fail ... [i]f the
array is not large enough to contain any complete characters".
Strictly interpreted, this means that a caller of these functions
cannot use their return values to detect truncation of a wide-character
string copied from more than one character cell in win. ncurses
reports any truncation with ERR.
X/Open Curses specifies inwstr, winwstr, mvinwstr, and mvwinwstr as
returning OK rather than a (wide) character count, unlike their non-
wide counterparts instr, winstr, mvinstr, and mvwinstr. ncurses
regards this inconsistency as an error in the standard.
The System V Interface Definition, Version 4 (1995), specified winwstr
and winnwstr (and the usual variants). These were later additions to
SVr4.x, not appearing in the first SVr4 (1989). Their synopses
described each function as taking an argument of type pointer-to-char
instead of pointer-to-wchar_t, despite describing them as "returning
the string of wchar_t in str". Presumably this was an error in the
System V Interface Definition.
curs_instr(3x) describes comparable functions of the ncurses library in
its non-wide-character configuration.
curses(3x), curs_in_wch(3x), curs_in_wchstr(3x)
ncurses 6.5 2025-08-16 curs_inwstr(3x)