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curs_instr

Section: Library calls (3X)
Updated: 202-1-20
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NAME

instr, winstr, mvinstr, mvwinstr, innstr, winnstr, mvinnstr, mvwinnstr - get a string from a curses window

SYNOPSIS

#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);

DESCRIPTION

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.

RETURN VALUE

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
.IP * 4 the curses screen has not been initialized,
.IP * 4 (for functions taking a WINDOW pointer argument) win is a null pointer, or
.IP * 4 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.

NOTES

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.

EXTENSIONS

innstr, winnstr, mvinnstr, and mvwinnstr's acceptance of negative n values is an ncurses extension.

PORTABILITY

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.
.IP * 4 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.
.IP * 4 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.

HISTORY

SVr3.1 (1987) introduced these functions.