werase(...) and erase() will copy blanks to every position on the window win or . For instance, when you set color attributes to a window and call werase() the window would be colored. I had some problems with COLOR_PAIRS when I defined other attributes then black on white so I wrote my own erase function (this is a low level access to the WINDOW structure):
The problem is, that ncurses sometimes makes no use of the window attributes when blanking the screen. For instance, in _clrtoeol.c, is BLANK defined as
so that the other window attributes get lost while the line is erased.