- 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 point-
- ed to by the character pointer str.
-
- wgetnstr reads at most n characters, thus preventing a
- possible overflow of the input buffer. Any attempt to en-
- ter 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 pre-
- vious character (typically a left motion).
+
+ 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 over-
+ flow of the input buffer. Any attempt to enter more characters (other
+ than the terminating newline or carriage return) causes a beep. Func-
+ tion 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 (typi-
+ cally a left motion).
-
-
RETURN VALUE
- All routines return the integer ERR upon failure and an OK
- (SVr4 specifies only "an integer value other than ERR")
- upon successful completion.
+
+
+ All routines return the integer ERR upon failure and an OK (SVr4 speci-
+ fies only "an integer value other than ERR") upon successful comple-
+ tion.
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.
+ 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_RE-
- SIZE rather than OK or ERR.
+ This implementation provides an extension as well. If a SIGWINCH in-
+ terrupts 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.
-
-
PORTABILITY
- 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 im-
- plementation returns ERR if the window pointer is null, or
- if the lower-level wgetch call returns an ERR.
-
- SVr3 and early SVr4 curses implementations did not reject
- function keys; the SVr4.0 documentation claimed that "spe-
- cial 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.
+
+ 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", with-
+ out 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).
-
-
SEE ALSO
- curses(3x), curs_getch(3x).
+ 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:
+
+ o ncurses 6.1 and PDCurses do not count the NUL in the given limit,
+ while
+
+ o Solaris SVr4 and NetBSD curses count the NUL as part of the limit.
+
+ o Solaris xcurses provides both: its wide-character wget_nstr re-
+ serves 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:
+
+ o Solaris SVr4 curses and PDCurses limit the result to 255 bytes.
+ Other Unix systems than Solaris are likely to use the same limit.
+
+ o Solaris xcurses limits the result to LINE_MAX bytes.
+
+ o 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.
+
+ o ncurses (before 6.2) assumes no particular limit for the result
+ from wgetstr, and treats the n parameter of wgetnstr like SVr4
+ curses.
+
+ o 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 ter-
+ minating NUL.
+
+
+