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 versus
execution time. They should be used where a precision of
1/
HZ (e.g., 10 msec on a 100
HZ machine,
see
hz(9)) is acceptable or where
performance is priority.
SEE ALSO
microtime(9),
timecounter(9),
tvtohz(9)
AUTHORS
This manual page was written by
Kelly Yancey
<
kbyanc@posi.net>.