Clocks and Timers [POSIX Section 14]

int clock_settime( clockid_t clock_id,
const struct timespec *tp); 
int clock_gettime( clockid_t clock_id, struct timespec *tp); 
int clock_getres( clockid_t clock_id, struct timespec *tp); 
int timer_create( clockid_t clock_id, struct sigevent *evp,
	          timer_t *timer_id);
int timer_delete( timer_t timer_id ); 
int timer_settime( timer_t timerid, int flags,
	           const struct itimerspec *value,
	           struct itimerspec *ovalue ); 
int timer_gettime( timer_t timerid, struct itimerspec *value ); 
int timer_getoverrun( timer_t timerid ); 
int nanosleep( const struct timespec *rqtp, struct timespec *rmtp);
int gettimeofday(struct timeval *tv, struct timezone* tz);