freebsd-nq/share/man/man9/microtime.9

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.Dd September 16, 2004
.Dt MICROTIME 9
.Os
.Sh NAME
.Nm bintime ,
.Nm getbintime ,
.Nm microtime ,
.Nm getmicrotime ,
.Nm nanotime ,
.Nm getnanotime
.Nd get the current time
.Sh SYNOPSIS
.In sys/time.h
.Ft void
.Fn bintime "struct bintime *bt"
.Ft void
.Fn getbintime "struct bintime *bt"
.Ft void
.Fn microtime "struct timeval *tv"
.Ft void
.Fn getmicrotime "struct timeval *tv"
.Ft void
.Fn nanotime "struct timespec *ts"
.Ft void
.Fn getnanotime "struct timespec *tsp"
.Sh DESCRIPTION
The
.Fn bintime
and
.Fn getbintime
functions store the system time as a
.Ft struct bintime
at the addresses specified by
.Fa bt .
The
.Fn microtime
and
.Fn getmicrotime
functions perform the same utility, but record the time as a
.Ft struct timeval
instead.
Similarly the
.Fn nanotime
and
.Fn getnanotime
functions store the time as a
.Ft struct timespec .
.Pp
.Fn Bintime ,
.Fn microtime ,
and
.Fn nanotime
always query the timecounter to return the current time as precisely as
possible.
Whereas
.Fn getbintime ,
.Fn getmicrotime ,
and
.Fn getnanotime
functions are abstractions which return a less precise, but
faster to obtain, time.
.Pp
The intent of the
.Fn getbintime ,
.Fn getmicrotime ,
and
.Fn getnanotime
functions is to enforce the user's preference for timer accuracy versus
execution time.
.Sh SEE ALSO
.Xr binuptime 9 ,
.Xr getbinuptime 9 ,
.Xr getmicrouptime 9 ,
.Xr getnanouptime 9 ,
.Xr microuptime 9 ,
.Xr nanouptime 9 ,
.Xr tvtohz 9
.Sh HISTORY
The
.Nm bintime
functions first appeared in
.Fx 5.0 .
The
.Nm
and
.Nm nanotime
functions first appeared in
.Fx 3.0
but existed in other incarnations since
.Bx 4.4 .
.Sh AUTHORS
This manual page was written by
.An Kelly Yancey Aq kbyanc@posi.net .