Provided by: ncurses-doc_6.5+20250216-1_all 
NAME
beep, flash - ring the (visual) bell of the terminal with curses
SYNOPSIS
#include <curses.h>
int beep(void);
int flash(void);
DESCRIPTION
beep and flash alert the terminal user: the former by sounding the terminal's audible alarm, and the
latter by visibly attracting attention. Commonly, a terminal implements a visual bell by momentarily
reversing the character foreground and background colors on the entire display; even a monochrome device
can do this. These functions each attempt the other alert type if the one requested is unavailable. If
neither is available, curses performs no action. Nearly all terminals have an audible alert mechanism
such as a bell or piezoelectric buzzer, but only some can flash the screen.
RETURN VALUE
These functions return OK on success and ERR on failure.
In ncurses, beep and flash return OK if the terminal type supports the corresponding capability: bell
(bel) for beep and flash_screen (flash) for flash. Otherwise they return ERR.
EXTENSIONS
In ncurses, these functions can return ERR.
PORTABILITY
X/Open Curses Issue 4 describes these functions. It specifies no error conditions for them.
On SVr4 curses, they always return OK, and X/Open Curses specifies them as doing so.
HISTORY
SVr2 (1984) introduced beep and flash.
SEE ALSO
ncurses(3NCURSES), terminfo(5)