netbsd man page for nanouptime

MICROUPTIME(9)						   BSD Kernel Developer's Manual					    MICROUPTIME(9)

NAME
     binuptime, getbinuptime, microuptime, getmicrouptime, nanouptime, getnanouptime -- get the time elapsed since boot

SYNOPSIS
     #include <sys/time.h>

     void
     binuptime(struct bintime *bt);

     void
     getbinuptime(struct bintime *bt);

     void
     microuptime(struct timeval *tv);

     void
     getmicrouptime(struct timeval *tv);

     void
     nanouptime(struct timespec *ts);

     void
     getnanouptime(struct timespec *tsp);

DESCRIPTION
     The binuptime() and getbinuptime() functions store the time elapsed since boot as a struct bintime at the address specified by bt.  The
     microuptime() and getmicrouptime() functions perform the same utility, but record the elapsed time as a struct timeval instead.  Similarly
     the nanouptime() and getnanouptime() functions store the elapsed time as a struct timespec.  The used structures are described in timeval(3).

     The binuptime(), microuptime(), and nanouptime() functions always query the timecounter to return the current time as precisely as possible.
     Whereas getbinuptime(), getmicrouptime(), and getnanouptime() functions are abstractions which return a less precise, but faster to obtain,
     time.

     The intent of the getbinuptime(), getmicrouptime(), and getnanouptime() functions is to enforce the user's preference for timer accuracy ver-
     sus execution time.  They should be used where a precision of 1/HZ (e.g., 10 msec on a 100HZ machine, see hz(9)) is acceptable or where per-
     formance is priority.

SEE ALSO
     microtime(9), timecounter(9), tvtohz(9)

AUTHORS
     This manual page was written by Kelly Yancey <kbyanc@posi.net>.

BSD
								   June 8, 2010 							       BSD