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).
touch(3NCURSES)