opensolaris man page for gethrtime

gethrtime(9F)						   Kernel Functions for Drivers 					     gethrtime(9F)

NAME
       gethrtime - get high resolution time

SYNOPSIS
       #include <sys/time.h>

       hrtime_t gethrtime(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.

RETURN VALUES
       gethrtime() always returns the current high-resolution real time. There are no error conditions.

CONTEXT
       There are no restrictions on the context from which gethrtime() can be called.

SEE ALSO
       proc(1), 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 guaranteed
       to be monotonic (it does not go backward, it does not periodically wrap) and linear (it does not occasionally speed up  or  slow  down  for
       adjustment, as the time of day can), but not necessarily unique: two sufficiently proximate calls might return the same value.

       The  time  base used for this function is the same as that for gethrtime(3C). Values returned by both of these functions can be interleaved
       for comparison purposes.

SunOS 5.11							     2 Oct 2007 						     gethrtime(9F)