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(opensolaris section 3c)
man page for gethrvtime

gethrtime(3C)						   Standard C Library Functions 					     gethrtime(3C)

gethrtime, gethrvtime - get high resolution time SYNOPSIS
#include <sys/time.h> hrtime_t gethrtime(void); hrtime_t gethrvtime(void); DESCRIPTION
The gethrtime() function returns the current high-resolution real time. Time is expressed as nanoseconds since some arbitrary time in the past; it is not correlated in any way to the time of day, and thus is not subject to resetting or drifting by way of adjtime(2) or settime- ofday(3C). The hi-res timer is ideally suited to performance measurement tasks, where cheap, accurate interval timing is required. The gethrvtime() function returns the current high-resolution LWP virtual time, expressed as total nanoseconds of execution time. The gethrtime() and gethrvtime() functions both return an hrtime_t, which is a 64-bit (long long) signed integer. EXAMPLES
The following code fragment measures the average cost of getpid(2): hrtime_t start, end; int i, iters = 100; start = gethrtime(); for (i = 0; i < iters; i++) getpid(); end = gethrtime(); printf("Avg getpid() time = %lld nsec\n", (end - start) / iters); ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
proc(1), adjtime(2), gettimeofday(3C), settimeofday(3C), attributes(5) NOTES
Although the units of hi-res time are always the same (nanoseconds), the actual resolution is hardware dependent. Hi-res time is guaran- teed to be monotonic (it won't go backward, it won't periodically wrap) and linear (it won't occasionally speed up or slow down for adjust- ment, like the time of day can), but not necessarily unique: two sufficiently proximate calls may return the same value. SunOS 5.11 7 Sep 2004 gethrtime(3C)

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