osx man page for flash

curs_beep(3X)															     curs_beep(3X)

NAME
       beep, flash - curses bell and screen flash routines

SYNOPSIS
       #include <curses.h>

       int beep(void);
       int flash(void);

DESCRIPTION
       The  beep  and  flash routines are used to alert the terminal user.  The routine beep sounds an audible alarm on the terminal, if possible;
       otherwise it flashes the screen (visible bell).	The routine flash flashes the screen, and if that is not possible, sounds the  alert.	If
       neither alert is possible, nothing happens.  Nearly all terminals have an audible alert (bell or beep), but only some can flash the screen.

RETURN VALUE
       These routines return OK if they succeed in beeping or flashing, ERR otherwise.

EXTENSIONS
       SVr4's beep and flash routines always returned OK, so it was not possible to tell when the beep or flash failed.

PORTABILITY
       These functions are described in the XSI Curses standard, Issue 4.  Like SVr4, it specifies that they always return OK.

SEE ALSO
       curses(3X)

																     curs_beep(3X)