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 structures for use with the clock_gettime(2), clock_settime(2), gettimeofday(2) and settimeofday(2) calls. The timeval structure is defined in<sys/time.h> as:
struct timeval {
long tv_sec; /* seconds since Jan. 1, 1970 */
long tv_usec; /* and microseconds */
};
<time.h> as:
struct timespec {
time_t tv_nsec; /* 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
HISTORY
The timeradd() family of macros were
imported from NetBSD 1.1, and appeared in
FreeBSD 2.2.6. The
timespecadd() family of macros were imported from
NetBSD 1.3 into FreeBSD 3.0,
though they were not exposed to userland until FreeBSD
12.0.