mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-11-14 06:12:01 +01:00
6662c2312e
As kib@ noted:
> Obviously gettimeofday(2) is not going to be removed
> even in the far future.
Reported by: kib
Fixes: 4395d3ced5 Document that gettimeofday() is obsolescent
MFC after: 3 days
150 lines
4.4 KiB
Groff
150 lines
4.4 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.Dd April 28, 2024
|
|
.Dt GETTIMEOFDAY 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm gettimeofday ,
|
|
.Nm settimeofday
|
|
.Nd get/set date and time
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In sys/time.h
|
|
.Ft int
|
|
.Fn gettimeofday "struct timeval *tp" "struct timezone *tzp"
|
|
.Ft int
|
|
.Fn settimeofday "const struct timeval *tp" "const struct timezone *tzp"
|
|
.Sh DESCRIPTION
|
|
.Em Note :
|
|
The
|
|
.Nm gettimeofday
|
|
function
|
|
.Po but not
|
|
.Nm settimeofday Pc
|
|
is obsolescent.
|
|
See the
|
|
.Sx STANDARDS
|
|
section for more details.
|
|
.Pp
|
|
The system's notion of the current Greenwich time and the current time
|
|
zone is obtained with the
|
|
.Fn gettimeofday
|
|
system call, and set with the
|
|
.Fn settimeofday
|
|
system call.
|
|
The time is expressed in seconds and microseconds
|
|
since midnight (0 hour), January 1, 1970.
|
|
The resolution of the system
|
|
clock is hardware dependent, and the time may be updated continuously or
|
|
in
|
|
.Dq ticks .
|
|
If
|
|
.Fa tp
|
|
or
|
|
.Fa tzp
|
|
is NULL, the associated time
|
|
information will not be returned or set.
|
|
.Pp
|
|
The structures pointed to by
|
|
.Fa tp
|
|
and
|
|
.Fa tzp
|
|
are defined in
|
|
.In sys/time.h
|
|
as:
|
|
.Bd -literal
|
|
struct timeval {
|
|
time_t tv_sec; /* seconds */
|
|
suseconds_t tv_usec; /* and microseconds */
|
|
};
|
|
|
|
struct timezone {
|
|
int tz_minuteswest; /* minutes west of Greenwich */
|
|
int tz_dsttime; /* type of dst correction */
|
|
};
|
|
.Ed
|
|
.Pp
|
|
The
|
|
.Vt timezone
|
|
structure indicates the local time zone
|
|
(measured in minutes of time westward from Greenwich),
|
|
and a flag that, if nonzero, indicates that
|
|
Daylight Saving time applies locally during
|
|
the appropriate part of the year.
|
|
The kernel generally does not track these values and they
|
|
are usually returned as zero.
|
|
Use
|
|
.Xr localtime 3
|
|
to find the offset for the currently active timezone.
|
|
.Pp
|
|
Only the super-user may set the time of day or time zone.
|
|
If the system is running at securelevel >= 2 (see
|
|
.Xr init 8 ) ,
|
|
the time may only be advanced or retarded by a maximum of one second.
|
|
This limitation is imposed to prevent a malicious super-user
|
|
from setting arbitrary time stamps on files.
|
|
The system time can be adjusted backwards without restriction using the
|
|
.Xr adjtime 2
|
|
system call even when the system is secure.
|
|
.Sh RETURN VALUES
|
|
.Rv -std
|
|
.Sh ERRORS
|
|
The following error codes may be set in
|
|
.Va errno :
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The supplied
|
|
.Fa timeval
|
|
value is invalid.
|
|
.It Bq Er EPERM
|
|
A user other than the super-user attempted to set the time.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr date 1 ,
|
|
.Xr adjtime 2 ,
|
|
.Xr clock_gettime 2 ,
|
|
.Xr ctime 3 ,
|
|
.Xr timeradd 3 ,
|
|
.Xr clocks 7
|
|
.Sh STANDARDS
|
|
The
|
|
.Nm gettimeofday
|
|
function is considered obsolescent and its usage discouraged by
|
|
.\" XXX: This should be replaced in the future when an appropriate argument to
|
|
.\" the St macro is available: -p1003.1-2017
|
|
.No IEEE Std 1003.1-2008, 2017 Edition (\\(LqPOSIX.1\\(Rq) .
|
|
Applications should use the
|
|
.Xr clock_gettime 2
|
|
function instead.
|
|
.Sh HISTORY
|
|
The
|
|
.Fn gettimeofday
|
|
system call appeared in
|
|
.Bx 4.2 .
|