Function friday_13th

src/calendar.c:205–212

}

boolean
friday_13th(void)
{
    struct tm *lt = getlt();

    /* tm_wday (day of week; 0==Sunday) == 5 => Friday */
    return (boolean) (lt->tm_wday == 5 && lt->tm_mday == 13);
}

int
night(void)