#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.
