1curs_getstr(3X)                                                curs_getstr(3X)
2
3
4

NAME

6       getstr, getnstr, wgetstr, wgetnstr, mvgetstr, mvgetnstr, mvwgetstr,
7       mvwgetnstr - accept character strings from curses terminal keyboard
8

SYNOPSIS

10       #include <curses.h>
11
12       int getstr(char *str);
13       int getnstr(char *str, int n);
14       int wgetstr(WINDOW *win, char *str);
15       int wgetnstr(WINDOW *win, char *str, int n);
16
17       int mvgetstr(int y, int x, char *str);
18       int mvwgetstr(WINDOW *win, int y, int x, char *str);
19       int mvgetnstr(int y, int x, char *str, int n);
20       int mvwgetnstr(WINDOW *win, int y, int x, char *str, int n);
21

DESCRIPTION

23       The function getstr is equivalent to a series of calls to getch,  until
24       a  newline or carriage return is received (the terminating character is
25       not included in the returned string).  The resulting value is placed in
26       the area pointed to by the character pointer str, followed by a NUL.
27
28       wgetnstr  reads  at most n characters, thus preventing a possible over‐
29       flow of the input buffer.  Any attempt to enter more characters  (other
30       than  the terminating newline or carriage return) causes a beep.  Func‐
31       tion keys also cause a beep and  are  ignored.   The  getnstr  function
32       reads from the stdscr default window.
33
34       The  user's  erase and kill characters are interpreted.  If keypad mode
35       is on for the window, KEY_LEFT and KEY_BACKSPACE  are  both  considered
36       equivalent to the user's kill character.
37
38       Characters  input  are  echoed  only  if echo is currently on.  In that
39       case, backspace is echoed as deletion of the previous character  (typi‐
40       cally a left motion).
41

RETURN VALUE

43       All routines return the integer ERR upon failure and an OK (SVr4 speci‐
44       fies only “an integer value other than ERR”)  upon  successful  comple‐
45       tion.
46
47       X/Open defines no error conditions.
48
49       In  this  implementation, these functions return an error if the window
50       pointer is null, or if its timeout expires without having any data.
51
52       This implementation provides an extension as well.  If a  SIGWINCH  in‐
53       terrupts the function, it will return KEY_RESIZE rather than OK or ERR.
54
55       Functions  with  a  “mv”  prefix  first perform a cursor movement using
56       wmove, and return an error if the position is outside the window, or if
57       the window pointer is null.
58

NOTES

60       Note that getstr, mvgetstr, and mvwgetstr may be macros.
61

PORTABILITY

63       These  functions  are  described  in  the XSI Curses standard, Issue 4.
64       They read single-byte characters only.  The standard  does  not  define
65       any  error  conditions.   This implementation returns ERR if the window
66       pointer is null, or if the lower-level wgetch(3X) call returns an ERR.
67
68       SVr3 and early SVr4 curses  implementations  did  not  reject  function
69       keys;  the  SVr4.0  documentation  claimed that “special keys” (such as
70       function keys, “home” key, “clear” key, etc.) are “interpreted”,  with‐
71       out  giving details.  It lied.  In fact, the “character” value appended
72       to the string by those implementations was predictable but  not  useful
73       (being, in fact, the low-order eight bits of the key's KEY_ value).
74
75       The  functions  getnstr, mvgetnstr, and mvwgetnstr were present but not
76       documented in SVr4.
77
78       X/Open Curses, Issue 5 (2007) stated that these functions “read at most
79       n  bytes”  but  did not state whether the terminating NUL is counted in
80       that limit.  X/Open Curses, Issue 7 (2009) changed  that  to  say  they
81       “read at most n-1 bytes” to allow for the terminating NUL.  As of 2018,
82       some implementations do, some do not count it:
83
84       •   ncurses 6.1 and PDCurses do not count the NUL in the  given  limit,
85           while
86
87       •   Solaris SVr4 and NetBSD curses count the NUL as part of the limit.
88
89       •   Solaris  xcurses  provides  both:  its wide-character wget_nstr re‐
90           serves a NUL, but its wgetnstr does not count the NUL consistently.
91
92       In SVr4 curses, a negative value of n tells wgetnstr to assume that the
93       caller's  buffer  is large enough to hold the result, i.e., to act like
94       wgetstr.  X/Open Curses does not mention this (or anything  related  to
95       negative  or  zero  values  of n), however most implementations use the
96       feature, with different limits:
97
98       •   Solaris SVr4 curses and PDCurses limit the  result  to  255  bytes.
99           Other Unix systems than Solaris are likely to use the same limit.
100
101       •   Solaris xcurses limits the result to LINE_MAX bytes.
102
103       •   NetBSD  7  assumes no particular limit for the result from wgetstr.
104           However, it limits the wgetnstr parameter n to ensure  that  it  is
105           greater than zero.
106
107           A  comment in NetBSD's source code states that this is specified in
108           SUSv2.
109
110       •   ncurses (before 6.2) assumes no particular  limit  for  the  result
111           from  wgetstr,  and  treats  the  n parameter of wgetnstr like SVr4
112           curses.
113
114       •   ncurses 6.2 uses LINE_MAX, or  a  larger  (system-dependent)  value
115           which  the  sysconf  function  may provide.  If neither LINE_MAX or
116           sysconf is available, ncurses uses the POSIX value for LINE_MAX  (a
117           2048  byte limit).  In either case, it reserves a byte for the ter‐
118           minating NUL.
119

SEE ALSO

121       curses(3X), curs_getch(3X), curs_variables(3X).
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124
125                                                               curs_getstr(3X)
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