3.\"
4.\" Copyright (c) 1980, 1991, 1993
5.\" The Regents of the University of California. All rights reserved.
6.\"
7.\" Redistribution and use in source and binary forms, with or without
8.\" modification, are permitted provided that the following conditions
9.\" are met:
10.\" 1. Redistributions of source code must retain the above copyright
11.\" notice, this list of conditions and the following disclaimer.
12.\" 2. Redistributions in binary form must reproduce the above copyright
13.\" notice, this list of conditions and the following disclaimer in the
14.\" documentation and/or other materials provided with the distribution.
15.\" 3. All advertising materials mentioning features or use of this software
16.\" must display the following acknowledgement:
17.\" This product includes software developed by the University of
18.\" California, Berkeley and its contributors.
19.\" 4. Neither the name of the University nor the names of its contributors
20.\" may be used to endorse or promote products derived from this software
21.\" without specific prior written permission.
22.\"
23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33.\" SUCH DAMAGE.
34.\"
35.Dd May 8, 1997
36.Dt CLOCK_GETTIME 2
37.Os
38.Sh NAME
39.Nm clock_gettime ,
40.Nm clock_settime ,
41.Nm clock_getres
42.Nd get/set/calibrate date and time
43.Sh LIBRARY
44.Lb libc
45.Sh SYNOPSIS
46.Fd #include <sys/time.h>
47.Ft int
48.Fn clock_gettime "clockid_t clock_id" "struct timespec *tp"
49.Ft int
50.Fn clock_settime "clockid_t clock_id" "const struct timespec *tp"
51.Ft int
52.Fn clock_getres "clockid_t clock_id" "struct timespec *tp"
53.Sh DESCRIPTION
54The
55.Fn clock_gettime
56and
57.Fn clock_settime
58allow the calling process to retrieve or set the value used by a clock
59which is specifed by
60.Fa clock_id .
61.Pp
62.Fa clock_id
63can be one of three values: CLOCK_REALTIME for time that increments as
64a wall clock should, CLOCK_VIRTUAL for time that increments only when
65the CPU is running in user mode on behalf of the calling process, or
66CLOCK_PROF for time that increments when the CPU is running in user or
67kernel mode.
68.Pp
69The structure pointed to by
70.Fa tp
71is defined in
72.Ao Pa sys/time.h Ac
73as:
74.Pp
75.Bd -literal
76struct timespec {
77 time_t tv_sec; /* seconds */
78 long tv_nsec; /* and nanoseconds */
79};
80.Ed
81.Pp
82Only the super-user may set the time of day.
83If the system securelevel is greater than 1 (see
84.Xr init 8 ) ,
85the time may only be advanced.
86This limitation is imposed to prevent a malicious super-user
87from setting arbitrary time stamps on files.
88The system time can still be adjusted backwards using the
89.Xr adjtime 2
90system call even when the system is secure.
91.Pp
92The resolution (granularity) of a clock is returned by the
93.Fn clock_getres
94call. This value is placed in a (non-NULL)
95.Fa *tp .
96.Sh RETURN VALUES
97A 0 return value indicates that the call succeeded.
98A -1 return value indicates an error occurred, and in this
99case an error code is stored into the global variable
100.Va errno .
101.Sh ERRORS
102The following error codes may be set in
103.Va errno :
104.Bl -tag -width Er
105.It Bq Er EINVAL
106The
107.Fa clock_id
108was not a valid value.
109.It Bq Er EFAULT
110The
111.Fa *tp
112argument address referenced invalid memory.
113.It Bq Er EPERM
114A user other than the super-user attempted to set the time.
115.El
116.Sh SEE ALSO
117.Xr date 1 ,
118.Xr adjtime 2 ,
119.Xr ctime 3 ,
120.Xr timed 8
121.Sh STANDARDS
122The
123.Fn clock_gettime ,
| 3.\"
4.\" Copyright (c) 1980, 1991, 1993
5.\" The Regents of the University of California. All rights reserved.
6.\"
7.\" Redistribution and use in source and binary forms, with or without
8.\" modification, are permitted provided that the following conditions
9.\" are met:
10.\" 1. Redistributions of source code must retain the above copyright
11.\" notice, this list of conditions and the following disclaimer.
12.\" 2. Redistributions in binary form must reproduce the above copyright
13.\" notice, this list of conditions and the following disclaimer in the
14.\" documentation and/or other materials provided with the distribution.
15.\" 3. All advertising materials mentioning features or use of this software
16.\" must display the following acknowledgement:
17.\" This product includes software developed by the University of
18.\" California, Berkeley and its contributors.
19.\" 4. Neither the name of the University nor the names of its contributors
20.\" may be used to endorse or promote products derived from this software
21.\" without specific prior written permission.
22.\"
23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33.\" SUCH DAMAGE.
34.\"
35.Dd May 8, 1997
36.Dt CLOCK_GETTIME 2
37.Os
38.Sh NAME
39.Nm clock_gettime ,
40.Nm clock_settime ,
41.Nm clock_getres
42.Nd get/set/calibrate date and time
43.Sh LIBRARY
44.Lb libc
45.Sh SYNOPSIS
46.Fd #include <sys/time.h>
47.Ft int
48.Fn clock_gettime "clockid_t clock_id" "struct timespec *tp"
49.Ft int
50.Fn clock_settime "clockid_t clock_id" "const struct timespec *tp"
51.Ft int
52.Fn clock_getres "clockid_t clock_id" "struct timespec *tp"
53.Sh DESCRIPTION
54The
55.Fn clock_gettime
56and
57.Fn clock_settime
58allow the calling process to retrieve or set the value used by a clock
59which is specifed by
60.Fa clock_id .
61.Pp
62.Fa clock_id
63can be one of three values: CLOCK_REALTIME for time that increments as
64a wall clock should, CLOCK_VIRTUAL for time that increments only when
65the CPU is running in user mode on behalf of the calling process, or
66CLOCK_PROF for time that increments when the CPU is running in user or
67kernel mode.
68.Pp
69The structure pointed to by
70.Fa tp
71is defined in
72.Ao Pa sys/time.h Ac
73as:
74.Pp
75.Bd -literal
76struct timespec {
77 time_t tv_sec; /* seconds */
78 long tv_nsec; /* and nanoseconds */
79};
80.Ed
81.Pp
82Only the super-user may set the time of day.
83If the system securelevel is greater than 1 (see
84.Xr init 8 ) ,
85the time may only be advanced.
86This limitation is imposed to prevent a malicious super-user
87from setting arbitrary time stamps on files.
88The system time can still be adjusted backwards using the
89.Xr adjtime 2
90system call even when the system is secure.
91.Pp
92The resolution (granularity) of a clock is returned by the
93.Fn clock_getres
94call. This value is placed in a (non-NULL)
95.Fa *tp .
96.Sh RETURN VALUES
97A 0 return value indicates that the call succeeded.
98A -1 return value indicates an error occurred, and in this
99case an error code is stored into the global variable
100.Va errno .
101.Sh ERRORS
102The following error codes may be set in
103.Va errno :
104.Bl -tag -width Er
105.It Bq Er EINVAL
106The
107.Fa clock_id
108was not a valid value.
109.It Bq Er EFAULT
110The
111.Fa *tp
112argument address referenced invalid memory.
113.It Bq Er EPERM
114A user other than the super-user attempted to set the time.
115.El
116.Sh SEE ALSO
117.Xr date 1 ,
118.Xr adjtime 2 ,
119.Xr ctime 3 ,
120.Xr timed 8
121.Sh STANDARDS
122The
123.Fn clock_gettime ,
|