int tv_diff(const struct timeval *b, const struct timeval *a,
struct timeval *diff);
long unsigned tv2ms(const struct timeval *tv);
-void d2tv(double x, struct timeval *tv);
void tv_add(const struct timeval *a, const struct timeval *b,
struct timeval *sum);
void tv_scale(const unsigned long mult, const struct timeval *tv,