#endif
typedef unsigned long long usec_t;
+typedef long long susec_t;
typedef usec_t heartbeat_t;
extern usec_t timeval_usec(struct timeval *ts);
extern usec_t dt_usec(struct timeval *now, struct timeval *old);
+extern susec_t dt_usec_signed(struct timeval *now, struct timeval *old);
extern void heartbeat_init(heartbeat_t *hb);