Flashes the screen.
Curses Library (libcurses.a)
#include <curses.h>
int flash(void);
The flash subroutine alerts the user. It flashes the screen, or if that is not possible, it sounds the audible alarm on the terminal. If neither signal is possible, nothing happens.
The flash subroutine always returns OK.
To cause the terminal to flash, enter:
flash();