Provided by: ncurses-doc_6.2-0ubuntu2_all bug


       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

       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:

       ·   ncurses 6.1 and PDCurses do not count the NUL in the given limit, while

       ·   Solaris SVr4 and NetBSD curses count the NUL as part of the limit.

       ·   Solaris  xcurses  provides  both: its wide-character wget_nstr reserves 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:

       ·   Solaris  SVr4  curses  and PDCurses limit the result to 255 bytes.  Other Unix systems
           than Solaris are likely to use the same limit.

       ·   Solaris xcurses limits the result to LINE_MAX bytes.

       ·   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.

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

       ·   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 terminating NUL.


       ncurses(3NCURSES), getch(3NCURSES), curses_variables(3NCURSES).