beep.c

static void beep(unsigned int ms, unsigned int freq)
{
    int fd, arg;

    fd = open("/dev/console", O_RDWR);
    if (fd < 0) {
      perror(strerror(errno));
      return;
    }
    arg = (ms << 16) | freq;
    ioctl(fd, KDMKTONE, arg);
    close(fd);
    usleep(ms*1000);
}