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 arbi-
     trary 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 settimeofday(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  gethr-
     time() 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 suffi-
     ciently 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.