NAME

timerclear, timerisset, timerisvalid, timercmp, timersub, timeradd, timespecclear, timespecisset, timespecisvalid, timespeccmp, timespecsub, timespecadd, TIMEVAL_TO_TIMESPEC, TIMESPEC_TO_TIMEVAL — manipulate time structures

SYNOPSIS

#include <sys/time.h>

void
timerclear(struct timeval *a);

int
timerisset(struct timeval *a);

int
timerisvalid(struct timeval *a);

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

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

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

void
timespecclear(struct timespec *a);

int
timespecisset(struct timespec *a);

int
timespecisvalid(struct timespec *a);

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

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

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

void
TIMEVAL_TO_TIMESPEC(struct timeval *tv, struct timespec *ts);

void
TIMESPEC_TO_TIMEVAL(struct timeval *tv, struct timespec *ts);

DESCRIPTION

The timer*() and timespec*() macros defined in <sys/time.h> simplify the use of timeval and timespec structures, respectively.

The following macros are available:

timerclear(a), timespecclear(a)

Set the time value in a to zero.

timerisset(a), timespecisset(a)

Test if the time value in a is non-zero.

timerisvalid(a)

Test if the microsecond value in a is greater than or equal to zero and less than one million.

timespecisvalid(a)

Test if the nanosecond value in a is greater than or equal to zero and less than one billion.

timercmp(a, b, operator), timespeccmp(a, b, operator)

Test if the expression a operator b is true, where operator is one of <, <=, ==, !=, >=, or >.

timersub(a, b, c), timespecsub(a, b, c)

Subtract b from a and store the result in c.

timeradd(a, b, c), timespecadd(a, b, c)

Add b to a and store the result in c.

TIMEVAL_TO_TIMESPEC(tv, ts)

Convert tv to a struct timespec and store the result in ts.

TIMESPEC_TO_TIMEVAL(tv, ts)

Convert ts to a struct timeval and store the result in tv.

RETURN VALUES

The macros returning int return 1 if the tested condition holds or 0 otherwise.

SEE ALSO

adjtime(2), clock_gettime(2), futex(2), futimens(2), futimes(2), getitimer(2), gettimeofday(2), kevent(2), nanosleep(2), ppoll(2), pselect(2)

STANDARDS

These macros are non-standard, though many systems offer them. Similar interfaces are often available in their absence.

HISTORY

The macros timerclear(), timerisset(), and timercmp() first appeared in 4.1cBSD, TIMEVAL_TO_TIMESPEC() and TIMESPEC_TO_TIMEVAL() in 4.4BSD, timersub() and timeradd() in NetBSD 1.1, and timerisvalid() in OpenBSD 6.5.

CAVEATS

The argument ordering for TIMESPEC_TO_TIMEVAL() is unintuitive.