freebsd-skq/share/man/man9/microuptime.9

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.Dd February 21, 2015
.Dt MICROUPTIME 9
.Os
.Sh NAME
.Nm binuptime ,
.Nm getbinuptime ,
.Nm microuptime ,
.Nm getmicrouptime ,
.Nm nanouptime ,
.Nm getnanouptime ,
.Nm sbinuptime ,
.Nm getsbinuptime
.Nd get the time elapsed since boot
.Sh SYNOPSIS
.In sys/time.h
.Ft void
.Fn binuptime "struct bintime *bt"
.Ft void
.Fn getbinuptime "struct bintime *bt"
.Ft void
.Fn microuptime "struct timeval *tv"
.Ft void
.Fn getmicrouptime "struct timeval *tv"
.Ft void
.Fn nanouptime "struct timespec *ts"
.Ft void
.Fn getnanouptime "struct timespec *tsp"
.Ft sbintime_t
.Fn sbinuptime "void"
.Ft sbintime_t
.Fn getsbinuptime "void"
.Sh DESCRIPTION
The
.Fn binuptime
and
.Fn getbinuptime
functions store the time elapsed since boot as a
.Vt "struct bintime"
at the address specified by
.Fa bt .
The
.Fn microuptime
and
.Fn getmicrouptime
functions perform the same utility, but record the elapsed time as a
.Vt "struct timeval"
instead.
Similarly the
.Fn nanouptime
and
.Fn getnanouptime
functions store the elapsed time as a
.Vt "struct timespec" .
The
.Fn sbinuptime
and
.Fn getsbinuptime
functions return the time elapsed since boot as a
.Vt "sbintime_t" .
.Pp
The
.Fn binuptime ,
.Fn microuptime ,
.Fn nanouptime ,
and
.Fn sbinuptime
functions
always query the timecounter to return the current time as precisely as
possible.
Whereas
.Fn getbinuptime ,
.Fn getmicrouptime ,
.Fn getnanouptime ,
and
.Fn getsbinuptime
functions are abstractions which return a less precise, but
faster to obtain, time.
.Pp
The intent of the
.Fn getbinuptime ,
.Fn getmicrouptime ,
.Fn getnanouptime ,
and
.Fn getsbinuptime
functions is to enforce the user's preference for timer accuracy versus
execution time.
.Sh SEE ALSO
.Xr bintime 9 ,
.Xr get_cyclecount 9 ,
.Xr getbintime 9 ,
.Xr getmicrotime 9 ,
.Xr getnanotime 9 ,
.Xr microtime 9 ,
.Xr nanotime 9 ,
.Xr tvtohz 9
.Sh AUTHORS
This manual page was written by
.An Kelly Yancey Aq Mt kbyanc@posi.net .