pthread_cond_timedwait example

pthread_cond_timedwait_nanoseconds.h

static inline
void timeval_to_timespec(const struct timeval * tv, struct timespec * ts)
{
	ts->tv_sec  = tv->tv_sec;
	ts->tv_nsec = tv->tv_usec * 1000;
}

static inline
void timespec_to_timeval(const struct timespec * ts, struct timeval * tv)
{
	tv->tv_sec  = ts->tv_sec;
	tv->tv_usec = ts->tv_nsec / 1000;
}

static inline
void timespec_now(struct timespec * ts)
{
#	if HAVE_CLOCK_GETTIME
	if (clock_gettime(CLOCK_REALTIME, ts) < 0) {
		ts->tv_sec  = -1;
		ts->tv_nsec = -1;
	}
#	elif HAVE_GETTIMEOFDAY
	struct timeval tv;
	gettimeofday(&tv, NULL);
	timeval_to_timespec(tv, ts);
#	else
	ts->tv_sec  = 0;
	ts->tv_nsec = 0;
#	endif
}

static inline
unsigned long timespec_to_nanoseconds(const struct timespec * ts)
{
	return (unsigned long)ts->tv_sec * 1000000000UL + (unsigned long)ts->tv_nsec;
}

static inline
void nanoseconds_to_timespec(unsigned long nanoseconds, struct timespec * ts)
{
	ts->tv_sec  = (nanoseconds / 1000000000UL);
	ts->tv_nsec = (nanoseconds % 1000000000UL);
}

static inline
void add_nanoseconds_to_timespec(unsigned long nanoseconds, struct timespec * ts)
{
	ts->tv_sec  += (nanoseconds / 1000000000UL);
	ts->tv_nsec += (nanoseconds % 1000000000UL);
}

static inline
int pthread_cond_timedwait_nanoseconds(
	  pthread_cond_t * restrict cond
	, pthread_mutex_t * restrict mutex
	, unsigned long nanoseconds
) {
	struct timespec abstime;

	timespec_now(&abstime);
	add_nanoseconds_to_timespec(nanoseconds, &abstime);
	return pthread_cond_timedwait(cond, mutex, &abstime);
}