xref: /freebsd/share/man/man9/microtime.9 (revision f0adf7f5cdd241db2f2c817683191a6ef64a4e95)
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25.\"    $FreeBSD$
26.\"
27.Dd January 3, 2000
28.Dt MICROTIME 9
29.Os
30.Sh NAME
31.Nm microtime ,
32.Nm getmicrotime ,
33.Nm nanotime ,
34.Nm getnanotime
35.Nd get the current time
36.Sh SYNOPSIS
37.In sys/time.h
38.Ft void
39.Fn microtime "struct timeval *tv"
40.Ft void
41.Fn getmicrotime "struct timeval *tv"
42.Ft void
43.Fn nanotime "struct timespec *ts"
44.Ft void
45.Fn getnanotime "struct timespec *tsp"
46.Sh DESCRIPTION
47The
48.Fn microtime
49and
50.Fn getmicrotime
51functions store the system time as a
52.Ft struct timeval
53at the address specified by
54.Fa tv .
55The
56.Fn nanotime
57and
58.Fn getnanotime
59functions perform the same utility, but record the time as a
60.Ft struct timespec
61instead.
62.Pp
63.Fn Microtime
64and
65.Fn nanotime
66always query the timecounter to return the current time as precisely as
67possible.
68Whereas
69.Fn getmicrotime
70and
71.Fn getnanotime
72functions are abstractions which return a less precise, but
73faster to obtain, time.
74.Pp
75The intent of the
76.Fn getmicrotime
77and
78.Fn getnanotime
79functions is to enforce the user's preference for timer accuracy versus
80execution time.
81.Sh SEE ALSO
82.Xr getmicrouptime 9 ,
83.Xr getnanouptime 9 ,
84.Xr microuptime 9 ,
85.Xr nanouptime 9 ,
86.Xr tvtohz 9
87.Sh HISTORY
88The
89.Nm
90and
91.Nm nanotime
92functions first appeared in
93.Fx 3.0
94but existed in other incarnations since
95.Bx 4.4
96.Sh AUTHORS
97This manual page was written by
98.An Kelly Yancey Aq kbyanc@posi.net .
99