xref: /freebsd/share/man/man9/microtime.9 (revision 193d9e768ba63fcfb187cfd17f461f7d41345048)
1.\" Copyright (c) 2000 Kelly Yancey
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\"    notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\"    notice, this list of conditions and the following disclaimer in the
11.\"    documentation and/or other materials provided with the distribution.
12.\"
13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23.\" SUCH DAMAGE.
24.\"
25.\" $FreeBSD$
26.\"
27.Dd September 16, 2004
28.Dt MICROTIME 9
29.Os
30.Sh NAME
31.Nm bintime ,
32.Nm getbintime ,
33.Nm microtime ,
34.Nm getmicrotime ,
35.Nm nanotime ,
36.Nm getnanotime
37.Nd get the current time
38.Sh SYNOPSIS
39.In sys/time.h
40.Ft void
41.Fn bintime "struct bintime *bt"
42.Ft void
43.Fn getbintime "struct bintime *bt"
44.Ft void
45.Fn microtime "struct timeval *tv"
46.Ft void
47.Fn getmicrotime "struct timeval *tv"
48.Ft void
49.Fn nanotime "struct timespec *ts"
50.Ft void
51.Fn getnanotime "struct timespec *tsp"
52.Sh DESCRIPTION
53The
54.Fn bintime
55and
56.Fn getbintime
57functions store the system time as a
58.Vt "struct bintime"
59at the addresses specified by
60.Fa bt .
61The
62.Fn microtime
63and
64.Fn getmicrotime
65functions perform the same utility, but record the time as a
66.Vt "struct timeval"
67instead.
68Similarly the
69.Fn nanotime
70and
71.Fn getnanotime
72functions store the time as a
73.Vt "struct timespec" .
74.Pp
75The
76.Fn bintime ,
77.Fn microtime ,
78and
79.Fn nanotime
80functions
81always query the timecounter to return the current time as precisely as
82possible.
83Whereas
84.Fn getbintime ,
85.Fn getmicrotime ,
86and
87.Fn getnanotime
88functions are abstractions which return a less precise, but
89faster to obtain, time.
90.Pp
91The intent of the
92.Fn getbintime ,
93.Fn getmicrotime ,
94and
95.Fn getnanotime
96functions is to enforce the user's preference for timer accuracy versus
97execution time.
98.Sh SEE ALSO
99.Xr binuptime 9 ,
100.Xr getbinuptime 9 ,
101.Xr getmicrouptime 9 ,
102.Xr getnanouptime 9 ,
103.Xr microuptime 9 ,
104.Xr nanouptime 9 ,
105.Xr tvtohz 9
106.Sh HISTORY
107The
108.Nm bintime
109functions first appeared in
110.Fx 5.0 .
111The
112.Nm microtime
113and
114.Nm nanotime
115functions first appeared in
116.Fx 3.0
117but have existed in other incarnations since
118.Bx 4.4 .
119.Sh AUTHORS
120This manual page was written by
121.An Kelly Yancey Aq Mt kbyanc@posi.net .
122