NAME

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

SYNOPSIS

       #include <curses.h>

       int touchline(WINDOW *win, int start, int count);

       int touchwin(WINDOW *win);
       int wtouchln(WINDOW *win, int y, int n, int changed);

       int untouchwin(WINDOW *win);

       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 win‐
       dow  have been touched, by pretending that the entire window has been drawn on.  This is sometimes neces‐
       sary 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 com‐
       pletion, 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.

               The  constant  ERR  is  distinct  from TRUE and FALSE, which are the normal return values of this
               function.  Because the function returns a bool, returning ERR (which is neither TRUE  nor  FALSE)
               may not be supported by the compiler.

               To  provide error-checking and also match the X/Open function prototype, the ERR is provided by a
               macro named is_linetouched.  The actual function returns FALSE when it detects an error.

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

PORTABILITY

       These functions were introduced by SVr4.  The Solaris curses header file, for instance, defines  both  an
       actual function and macro for each.  The macros give the same result as the actual functions.  SVr4 curs‐
       es  does  not check the window parameter win to ensure that it is not NULL; otherwise this implementation
       behaves the same as SVr4.

       The XSI Curses standard, Issue 4 describes these functions, but defines no error conditions.

NOTES

       All of these routines except wtouchln may be macros.

SEE ALSO

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

                                                                                                 touch(3NCURSES)