| getstr(3NCURSES) | getstr(3NCURSES) |
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:
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:
ncurses(3NCURSES), getch(3NCURSES), curses_variables(3NCURSES).