Tribblix: manual page: timespec

TIMESPEC_GET(3C) Standard C Library Functions TIMESPEC_GET(3C)

NAME

timespec_get, timespec_getres - get time information

SYNOPSIS

#include <time.h>

int
timespec_get(struct timespec *ts, int base);

int
timespec_getres(struct timespec *ts, int base);

DESCRIPTION

The timespec_get() function provides access to nanosecond resolution
time. The timespec_getres() function provides access to the underlying
clock's resolution. The meaning and source of time is defined by the
base argument. The following values are defined for base:

TIME_UTC
Obtain the current time of day from the realtime clock on the
system. It represents the amount of time in second and
nanoseconds since the Epoch. This is logically equivalent to
calling clock_gettime(3C) with CLOCK_REALTIME.

TIME_MONOTONIC
The system's monotonic clock is a non-adjustable, high-
resolution clock. The returned value is not subject to
adjustments from time of day drift nor can it be set. This
clock is generally only useful for measuring elapsed time
relative to a prior reading. This is logically equivalent to
using the CLOCK_HIGHRES and CLOCK_MONOTONIC clocks or calling
gethrtime(3C).

TIME_THREAD_ACTIVE
This clock measures the elapsed system and user CPU-time of the
current thread. The amount of time it has spent executing code
is measured in seconds and nanoseconds. The pr_utime member of
the lwpsinfo_t or prusage_t structures discussed in proc(5) are
alternative ways to see the user component. The system
component is a combination of both the system and trap time
that the thread has experienced. In the lwpsinfo_t this is
covered solely by the pr_stime member. For the prusage_t these
are separated out into the pr_stime and pr_ttime members
respectively.

This is logically equivalent to using the
CLOCK_THREAD_CPUTIME_ID clock . This clock is optional and may
not be present on other platforms.

TIME_THREAD_ACTIVE_USR
This clock is similar to the TIME_THREAD_ACTIVE clock, except
it only counts user time that has elapsed. This is logically
equivalent to using the CLOCK_VIRTUAL clock or calling
gethrvtime(3C). This clock is an extension and may not be
available on other platforms.

TIME_ACTIVE
This clock measures the elapsed system and user CPU-time of the
current process, including all of its threads. None of the
process's children are counted in this measure, whether running
or terminated. The value read here will be the same as
combining the corresponding proc(5) psinfo_t structure's
pr_stime and pr_utime members. This clock is optional and may
not be present on other platforms.

For the definition of the timespec structure, see time.h(3HEAD).

RETURN VALUES

Upon successful completion, the timespec_get() and timespec_getres()
functions return the passed in value of base. Otherwise, 0 is returned
to represent an error.

ERRORS

Unlike other functions, the timespec_get() and timespec_getres()
functions are not defined to set errno. However, the timespec_get()
and timespec_getres() functions will fail if:

+o The value of base does not refer to a known time
specification.

+o There was an error obtaining the time for base.

INTERFACE STABILITY