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TIMERADD(3)		 BSD Library Functions Manual		   TIMERADD(3)

NAME
     timeradd, timersub, timerclear, timerisset, timercmp, timespecadd,
     timespecsub, timespecclear, timespecisset,	timespeccmp -- operations on
     timevals and timespecs

SYNOPSIS
     #include <sys/time.h>

     void
     timeradd(struct timeval *a, struct	timeval	*b, struct timeval *res);

     void
     timersub(struct timeval *a, struct	timeval	*b, struct timeval *res);

     void
     timerclear(struct timeval *tvp);

     int
     timerisset(struct timeval *tvp);

     int
     timercmp(struct timeval *a, struct	timeval	*b, CMP);

     void
     timespecadd(struct	timespec *a, struct timespec *b,
	 struct	timespec *res);

     void
     timespecsub(struct	timespec *a, struct timespec *b,
	 struct	timespec *res);

     void
     timespecclear(struct timespec *ts);

     int
     timespecisset(struct timespec *ts);

     int
     timespeccmp(struct	timespec *a, struct timespec *b, CMP);

DESCRIPTION
     These macros are provided for manipulating	timeval	and timespec struc-
     tures for use with	the clock_gettime(2), clock_settime(2),
     gettimeofday(2) and settimeofday(2) calls.	 The timeval structure is de-
     fined in <sys/time.h> as:

     struct timeval {
	     long    tv_sec;	     /*	seconds	since Jan. 1, 1970 */
	     long    tv_usec;	     /*	and microseconds */
     };
     And the timespec structure	is defined in <time.h> as:

     struct timespec {
	     time_t tv_sec;	     /*	seconds	*/
	     long   tv_nsec;	     /*	and nanoseconds	*/
     };

     timeradd()	and timespecadd() add the time information stored in a to b
     and store the result in res.  The results are simplified such that	the
     value of res-_tv_usec or res-_tv_nsec is always less than 1 second.

     timersub()	and timespecsub() subtract the time information	stored in b
     from a and	store the result in res.

     timerclear() and timespecclear() initialize their argument	to midnight (0
     hour) January 1st,	1970 (the Epoch).

     timerisset() and timespecisset() return true if their argument is set to
     any time value other than the Epoch.

     timercmp()	and timespeccmp() compare a to b using the comparison operator
     given in CMP, and return the result of that comparison.

SEE ALSO
     clock_gettime(2), gettimeofday(2)

HISTORY
     The timeradd() family of macros were imported from	NetBSD 1.1, and	ap-
     peared in FreeBSD 2.2.6.  The timespecadd() family	of macros were im-
     ported from NetBSD	1.3 into FreeBSD 3.0, though they were not exposed to
     userland until FreeBSD 12.0.

BSD				 July 30, 2018				   BSD
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY

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