# curs_touch 3x

    curs_touch(3x)                                                  curs_touch(3x)

## NAME

           touchwin, touchline, untouchwin, wtouchln, is_linetouched,
           is_wintouched - curses refresh control routines

## SYNOPSIS

           #include <curses.h>
           int touchwin(WINDOW *win);
           int touchline(WINDOW *win, int start, int count);
           int untouchwin(WINDOW *win);
           int wtouchln(WINDOW *win, int y, int n, int changed);
           bool is_linetouched(WINDOW *win, int line);
           bool is_wintouched(WINDOW *win);

## DESCRIPTION

           The touchwin and touchline routines throw away all optimization  infor-
           mation about which parts of the window have been touched, by pretending
           that the entire window has been drawn on.  This is sometimes  necessary
           when  using  overlapping  windows, since a change to one window affects
           the other window, but the records of which lines have been  changed  in
           the other window do not reflect the change.  The routine touchline only
           pretends that count lines have been changed, beginning with line start.

           The untouchwin routine marks all lines in the window as unchanged since
           the last call to wrefresh.

           The  wtouchln  routine makes n lines in the window, starting at line y,
           look as if they have (changed=1) or have not (changed=0)  been  changed
           since the last call to wrefresh.

           The is_linetouched and is_wintouched routines return TRUE if the speci-
           fied line/window was modified since the last call to  wrefresh;  other-
           wise  they  return  FALSE.   In addition, is_linetouched returns ERR if
           line is not valid for the given window.

## RETURN VALUE

           All routines return the integer ERR upon failure and an  integer  value
           other  than  ERR  upon successful completion, unless otherwise noted in
           the preceding routine descriptions.

           X/Open does not define any error conditions.  In this implementation

                  is_linetouched
                       returns an error if the window pointer is null, or  if  the
                       line  number  is outside the window.  Note that ERR is dis-
                       tinct from TRUE and FALSE, which are the normal return val-
                       ues of this function.

                  wtouchln
                       returns  an  error if the window pointer is null, or if the
                       line number is outside the window.

## PORTABILITY

           The XSI Curses standard, Issue 4 describes these functions.

           Some historic curses implementations had, as an  undocumented  feature,
           the  ability  to  do the equivalent of clearok(..., 1) by saying touch-
           win(stdscr) or clear(stdscr).  This will not work under ncurses.

## NOTES

           Note that all routines except wtouchln may be macros.

## SEE ALSO

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

                                                                    curs_touch(3x)