touch(3ncurses)

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
   information  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
   specified  line/window  was  modified  since the last call to wrefresh;
   otherwise 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
               distinct  from  TRUE and FALSE, which are the normal return
               values 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
   touchwin(stdscr) or clear(stdscr).  This will not work under ncurses.

NOTES

   Note that all routines except wtouchln may be macros.

SEE ALSO

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

                                                           touch(3NCURSES)

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