Differential D30988 Diff 92668 lib/libc/sys/clock_gettime.2

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lib/libc/sys/clock_gettime.2

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	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)			.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT			.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY			.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF			.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	.\" SUCH DAMAGE.			.\" SUCH DAMAGE.
	.\"			.\"
	.\" $FreeBSD$			.\" $FreeBSD$
	.\"			.\"
	.Dd May 13, 2021			.Dd July 1, 2021
	.Dt CLOCK_GETTIME 2			.Dt CLOCK_GETTIME 2
	.Os			.Os
	.Sh NAME			.Sh NAME
	.Nm clock_gettime ,			.Nm clock_gettime ,
	.Nm clock_settime ,			.Nm clock_settime ,
	.Nm clock_getres			.Nm clock_getres
	.Nd get/set/calibrate date and time			.Nd get/set/calibrate date and time
	.Sh LIBRARY			.Sh LIBRARY
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	or			or
	.Xr pthread_getcpuclockid 3			.Xr pthread_getcpuclockid 3
	as well as the following values:			as well as the following values:
	.Pp			.Pp
	.Bl -tag -width indent -compact			.Bl -tag -width indent -compact
	.It Dv CLOCK_REALTIME			.It Dv CLOCK_REALTIME
	.It Dv CLOCK_REALTIME_PRECISE			.It Dv CLOCK_REALTIME_PRECISE
	.It Dv CLOCK_REALTIME_FAST			.It Dv CLOCK_REALTIME_FAST
				.It Dv CLOCK_REALTIME_COARSE
	Increments as a wall clock should.			Increments as a wall clock should.
	.It Dv CLOCK_MONOTONIC			.It Dv CLOCK_MONOTONIC
	.It Dv CLOCK_MONOTONIC_PRECISE			.It Dv CLOCK_MONOTONIC_PRECISE
	.It Dv CLOCK_MONOTONIC_FAST			.It Dv CLOCK_MONOTONIC_FAST
				.It Dv CLOCK_MONOTONIC_COARSE
	Increments in SI seconds.			Increments in SI seconds.
	.It Dv CLOCK_UPTIME			.It Dv CLOCK_UPTIME
	.It Dv CLOCK_UPTIME_PRECISE			.It Dv CLOCK_UPTIME_PRECISE
	.It Dv CLOCK_UPTIME_FAST			.It Dv CLOCK_UPTIME_FAST
				.It Dv CLOCK_BOOTTIME
	Starts at zero when the kernel boots and increments			Starts at zero when the kernel boots and increments
	monotonically in SI seconds while the machine is running.			monotonically in SI seconds while the machine is running.
	.It Dv CLOCK_VIRTUAL			.It Dv CLOCK_VIRTUAL
	Increments only when			Increments only when
	the CPU is running in user mode on behalf of the calling process.			the CPU is running in user mode on behalf of the calling process.
	.It Dv CLOCK_PROF			.It Dv CLOCK_PROF
	Increments when the CPU is running in user or kernel mode.			Increments when the CPU is running in user or kernel mode.
	.It Dv CLOCK_SECOND			.It Dv CLOCK_SECOND
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	are analogs of corresponding IDs without _FAST suffix but do not perform			are analogs of corresponding IDs without _FAST suffix but do not perform
	a full time counter query, so their accuracy is one timer tick.			a full time counter query, so their accuracy is one timer tick.
	Similarly,			Similarly,
	.Fa CLOCK_REALTIME_PRECISE ,			.Fa CLOCK_REALTIME_PRECISE ,
	.Fa CLOCK_MONOTONIC_PRECISE ,			.Fa CLOCK_MONOTONIC_PRECISE ,
	.Fa CLOCK_UPTIME_PRECISE			.Fa CLOCK_UPTIME_PRECISE
	are used to get the most exact value as possible, at the expense of			are used to get the most exact value as possible, at the expense of
	execution time.			execution time.
				The clock IDs
				.Fa CLOCK_REALTIME_COARSE ,
				.Fa CLOCK_MONOTONIC_COARSE
				are aliases of corresponding IDs with _FAST suffix for compatibility with other
				kevansUnsubmitted Done Inline Actions s/wit/with/ kevans: s/wit/with/
				impAuthorUnsubmitted Done Inline Actions Changed locally. Will update if there's other changes. imp: Changed locally. Will update if there's other changes.
				systems.
				Finally,
				.Dv CLOCK_BOOTTIME
				is an alias for
				.Dv CLOCK_UPTIME
				for compatibility with other systems.
	.Pp			.Pp
	The structure pointed to by			The structure pointed to by
	.Fa tp			.Fa tp
	is defined in			is defined in
	.In sys/timespec.h			.In sys/timespec.h
	as:			as:
	.Bd -literal			.Bd -literal
	struct timespec {			struct timespec {
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