int tv_diff(const struct timeval *b, const struct timeval *a, struct timeval *diff); long unsigned tv2ms(const struct timeval*); void d2tv(double, struct timeval*); void tv_add(const struct timeval*, const struct timeval *, struct timeval *); void tv_scale(const unsigned long, const struct timeval *, struct timeval *); void tv_divide(const unsigned long divisor, const struct timeval *tv, struct timeval *result); void ms2tv(const long unsigned n, struct timeval *tv); int64_t get_current_time(void);