curs_getstr 3x

curs_getstr(3x)                                                curs_getstr(3x)


       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 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).


       All routines return the integer ERR upon failure and an OK (SVr4 speci-
       fies only "an integer value other than ERR")  upon  successful  comple-

       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  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.


       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).

       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,

       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

       o   ncurses (before 6.2) assumes no particular  limit  for  the  result
           from  wgetstr,  and  treats  the  n parameter of wgetnstr like SVr4

       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.


       curses(3x), curs_getch(3x), curs_variables(3x).