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curs_get_wstr 3x 2023-11-25 ncurses 6.4 Library calls

curs_get_wstr(3x)                Library calls               curs_get_wstr(3x)




NAME

       get_wstr,  getn_wstr,  wget_wstr,  wgetn_wstr, mvget_wstr, mvgetn_wstr,
       mvwget_wstr, mvwgetn_wstr - get a wide-character string from  a  curses
       terminal keyboard


SYNOPSIS

       #include <curses.h>

       int get_wstr(wint_t *wstr);
       int getn_wstr(wint_t *wstr, int n);
       int wget_wstr(WINDOW *win, wint_t *wstr);
       int wgetn_wstr(WINDOW *win, wint_t *wstr, int n);

       int mvget_wstr(int y, int x, wint_t *wstr);
       int mvgetn_wstr(int y, int x, wint_t *wstr, int n);
       int mvwget_wstr(WINDOW *win, int y, int x, wint_t *wstr);
       int mvwgetn_wstr(WINDOW *win, int y, int x, wint_t *wstr, int n);


DESCRIPTION

       The  function  wgetn_wstr  is  equivalent  to  a  series  of  calls  to
       wget_wch(3x) until a newline or carriage return terminates the series:

       o   The terminating character is not included in the returned string.

       o   An end-of-file condition is represented  by  WEOF,  as  defined  in
           <wchar.h>.

       o   In  all  instances,  the  end of the string is terminated by a null
           wchar_t.

       o   The function stores the result in the area pointed to by  the  wstr
           parameter.

       o   The function 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 user's erase and kill characters are interpreted:

       o   The  erase  character (e.g., ^H) erases the character at the end of
           the buffer, moving the cursor to the left.

           If keypad mode is on for the window, KEY_LEFT and KEY_BACKSPACE are
           both considered equivalent to the user's erase character.

       o   The kill character (e.g., ^U) erases the entire buffer, leaving the
           cursor at the beginning of the buffer.

       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).

       The getn_wstr, mvgetn_wstr, mvwgetn_wstr, and wgetn_wstr functions  are
       identical  to  the  get_wstr,  mvget_wstr,  mvwget_wstr,  and wget_wstr
       functions, respectively, except that the *n_* versions read at  most  n
       characters,  letting  the  application  prevent  overflow  of the input
       buffer.


RETURN VALUE

       All  of  these  functions  return  the  integer  OK   upon   successful
       completion.  If unsuccessful, they return ERR.

       X/Open defines no error conditions.

       In this implementation, these functions return an error

       o   if the window pointer is null,

       o   if its timeout expires without having any data, or

       o   if the associated call to wget_wch failed.

       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.


NOTES

       Any of these functions other than wgetn_wstr may be macros.

       Using  get_wstr,  mvget_wstr,  mvwget_wstr, or wget_wstr to read a line
       that overflows the array pointed to by wstr causes  undefined  results.
       The   use  of  getn_wstr,  mvgetn_wstr,  mvwgetn_wstr,  or  wgetn_wstr,
       respectively, is recommended.

       These functions cannot return KEY_ values because there is  no  way  to
       distinguish a KEY_ value from a valid wchar_t value.


PORTABILITY

       These functions are described in The Single Unix Specification, Version
       2.  No error conditions are defined.

       This implementation returns ERR if the window pointer is  null,  or  if
       the  lower-level  wget_wch call returns an ERR.  In the latter case, an
       ERR return without other data is treated as an  end-of-file  condition,
       and the returned array contains a WEOF followed by a null wchar_t.

       X/Open curses documented these functions to pass an array of wchar_t in
       1997, but that was an error because of this part of the description:

              The effect of get_wstr is as though a series of calls to get_wch
              were  made, until a newline character, end-of-line character, or
              end-of-file character is processed.

       The latter function get_wch can return a negative value, while  wchar_t
       is  a  unsigned  type.  All of the vendors implement this using wint_t,
       following the standard.

       X/Open  Curses,  Issue  7  (2009)  is  unclear  regarding  whether  the
       terminating  null  wchar_t  value is counted in the length parameter n.
       X/Open  Curses,  Issue  7  revised  the  corresponding  description  of
       wgetnstr   to   address  this  issue.   The  unrevised  description  of
       wget_nwstr can be interpreted either way.  This  implementation  counts
       the terminator in the length.

       X/Open  Curses  does  not  specify  what  happens  if  the  length n is
       negative.

       o   For analogy with wgetnstr, ncurses  6.2  uses  a  limit  (based  on
           LINE_MAX).

       o   Some  other  implementations (such as Solaris xcurses) do the same,
           while others (PDCurses) do not allow this.

       o   NetBSD 7 curses imitates ncurses 6.1 in this regard, treating a  -1
           as an indefinite number of characters.


SEE ALSO

       curses(3x), curs_getstr(3x), curs_get_wch(3x)



ncurses 6.4                       2023-11-25                 curs_get_wstr(3x)