2004-11-03 13:51:07 +00:00
|
|
|
.\" Hey Emacs! This file is -*- nroff -*- source.
|
|
|
|
.\"
|
|
|
|
.\" Copyright (c) 1995 Michael Chastain (mec@shell.portal.com), 15 April 1995.
|
|
|
|
.\"
|
|
|
|
.\" This is free documentation; you can redistribute it and/or
|
|
|
|
.\" modify it under the terms of the GNU General Public License as
|
|
|
|
.\" published by the Free Software Foundation; either version 2 of
|
|
|
|
.\" the License, or (at your option) any later version.
|
|
|
|
.\"
|
|
|
|
.\" The GNU General Public License's references to "object code"
|
|
|
|
.\" and "executables" are to be interpreted as the output of any
|
|
|
|
.\" document formatting or typesetting system, including
|
|
|
|
.\" intermediate and printed output.
|
|
|
|
.\"
|
|
|
|
.\" This manual is distributed in the hope that it will be useful,
|
|
|
|
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
|
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
|
.\" GNU General Public License for more details.
|
|
|
|
.\"
|
|
|
|
.\" You should have received a copy of the GNU General Public
|
|
|
|
.\" License along with this manual; if not, write to the Free
|
|
|
|
.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
|
|
|
|
.\" USA.
|
|
|
|
.\"
|
|
|
|
.\" Modified 1997-01-31 by Eric S. Raymond <esr@thyrsus.com>
|
|
|
|
.\" Modified 1997-07-30 by Paul Slootman <paul@wurtel.demon.nl>
|
2007-09-20 06:52:22 +00:00
|
|
|
.\" Modified 2004-05-27 by Michael Kerrisk <mtk.manpages@gmail.com>
|
2004-11-03 13:51:07 +00:00
|
|
|
.\"
|
2007-05-30 05:36:26 +00:00
|
|
|
.TH ADJTIMEX 2 2004-05-27 "Linux" "Linux Programmer's Manual"
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH NAME
|
|
|
|
adjtimex \- tune kernel clock
|
|
|
|
.SH SYNOPSIS
|
|
|
|
.B #include <sys/timex.h>
|
|
|
|
.sp
|
|
|
|
.BI "int adjtimex(struct timex *" "buf" );
|
|
|
|
.SH DESCRIPTION
|
2005-07-20 07:50:45 +00:00
|
|
|
Linux uses David L. Mills' clock adjustment algorithm (see RFC\ 1305).
|
2004-11-03 13:51:07 +00:00
|
|
|
The system call
|
2005-10-19 06:54:38 +00:00
|
|
|
.BR adjtimex ()
|
2004-11-03 13:51:07 +00:00
|
|
|
reads and optionally sets adjustment parameters for this algorithm.
|
|
|
|
It takes a pointer to a
|
2007-04-12 22:42:49 +00:00
|
|
|
.I timex
|
2004-11-03 13:51:07 +00:00
|
|
|
structure, updates kernel parameters from field values,
|
|
|
|
and returns the same structure with current kernel values.
|
|
|
|
This structure is declared as follows:
|
|
|
|
.PP
|
2007-12-19 06:16:04 +00:00
|
|
|
.in +4n
|
2004-11-03 13:51:07 +00:00
|
|
|
.nf
|
|
|
|
struct timex {
|
|
|
|
int modes; /* mode selector */
|
|
|
|
long offset; /* time offset (usec) */
|
|
|
|
long freq; /* frequency offset (scaled ppm) */
|
2008-01-30 10:46:05 +00:00
|
|
|
.\" FIXME -- what is the scaling unit? 2^16 ?
|
2004-11-03 13:51:07 +00:00
|
|
|
long maxerror; /* maximum error (usec) */
|
|
|
|
long esterror; /* estimated error (usec) */
|
|
|
|
int status; /* clock command/status */
|
|
|
|
long constant; /* pll time constant */
|
2008-03-19 11:52:55 +00:00
|
|
|
long precision; /* clock precision (usec) (read-only) */
|
2004-11-03 13:51:07 +00:00
|
|
|
long tolerance; /* clock frequency tolerance (ppm)
|
2008-03-19 11:52:55 +00:00
|
|
|
(read-only) */
|
|
|
|
struct timeval time; /* current time (read-only) */
|
2004-11-03 13:51:07 +00:00
|
|
|
long tick; /* usecs between clock ticks */
|
|
|
|
};
|
|
|
|
.fi
|
2007-12-19 06:16:04 +00:00
|
|
|
.in
|
2004-11-03 13:51:07 +00:00
|
|
|
.PP
|
|
|
|
The
|
|
|
|
.I modes
|
|
|
|
field determines which parameters, if any, to set.
|
|
|
|
It may contain a
|
|
|
|
.RI bitwise- or
|
|
|
|
combination of zero or more of the following bits:
|
|
|
|
.PP
|
2007-12-19 06:16:04 +00:00
|
|
|
.in +4n
|
2004-11-03 13:51:07 +00:00
|
|
|
.nf
|
|
|
|
#define ADJ_OFFSET 0x0001 /* time offset */
|
|
|
|
#define ADJ_FREQUENCY 0x0002 /* frequency offset */
|
|
|
|
#define ADJ_MAXERROR 0x0004 /* maximum time error */
|
|
|
|
#define ADJ_ESTERROR 0x0008 /* estimated time error */
|
|
|
|
#define ADJ_STATUS 0x0010 /* clock status */
|
|
|
|
#define ADJ_TIMECONST 0x0020 /* pll time constant */
|
|
|
|
#define ADJ_TICK 0x4000 /* tick value */
|
2005-10-20 15:11:10 +00:00
|
|
|
#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime() */
|
2004-11-03 13:51:07 +00:00
|
|
|
.fi
|
2007-12-19 06:16:04 +00:00
|
|
|
.in
|
2004-11-03 13:51:07 +00:00
|
|
|
.PP
|
|
|
|
Ordinary users are restricted to a zero value for
|
|
|
|
.IR mode .
|
|
|
|
Only the superuser may set any parameters.
|
|
|
|
.br
|
|
|
|
.ne 12v
|
|
|
|
.SH "RETURN VALUE"
|
|
|
|
On success,
|
2005-10-19 06:54:38 +00:00
|
|
|
.BR adjtimex ()
|
2004-11-03 13:51:07 +00:00
|
|
|
returns the clock state:
|
|
|
|
.PP
|
2007-12-19 06:16:04 +00:00
|
|
|
.in +4n
|
2004-11-03 13:51:07 +00:00
|
|
|
.nf
|
|
|
|
#define TIME_OK 0 /* clock synchronized */
|
|
|
|
#define TIME_INS 1 /* insert leap second */
|
|
|
|
#define TIME_DEL 2 /* delete leap second */
|
|
|
|
#define TIME_OOP 3 /* leap second in progress */
|
|
|
|
#define TIME_WAIT 4 /* leap second has occurred */
|
|
|
|
#define TIME_BAD 5 /* clock not synchronized */
|
|
|
|
.fi
|
2007-12-19 06:16:04 +00:00
|
|
|
.in
|
2004-11-03 13:51:07 +00:00
|
|
|
.PP
|
|
|
|
On failure,
|
2005-10-19 06:54:38 +00:00
|
|
|
.BR adjtimex ()
|
2004-11-03 13:51:07 +00:00
|
|
|
returns \-1 and sets
|
|
|
|
.IR errno .
|
|
|
|
.SH ERRORS
|
|
|
|
.TP
|
|
|
|
.B EFAULT
|
|
|
|
.I buf
|
|
|
|
does not point to writable memory.
|
|
|
|
.TP
|
|
|
|
.B EINVAL
|
|
|
|
An attempt is made to set
|
|
|
|
.I buf.offset
|
|
|
|
to a value outside the range \-131071 to +131071,
|
|
|
|
or to set
|
|
|
|
.I buf.status
|
|
|
|
to a value other than those listed above,
|
|
|
|
or to set
|
|
|
|
.I buf.tick
|
2007-04-12 22:42:49 +00:00
|
|
|
to a value outside the range
|
2004-11-03 13:51:07 +00:00
|
|
|
.RB 900000/ HZ
|
2007-04-12 22:42:49 +00:00
|
|
|
to
|
2004-11-03 13:51:07 +00:00
|
|
|
.RB 1100000/ HZ ,
|
|
|
|
where
|
|
|
|
.B HZ
|
|
|
|
is the system timer interrupt frequency.
|
|
|
|
.TP
|
|
|
|
.B EPERM
|
|
|
|
.I buf.mode
|
intro.1, time.1, adjtimex.2, capget.2, eventfd.2, fcntl.2, getrlimit.2, getsockopt.2, gettimeofday.2, intro.2, ioctl_list.2, ioperm.2, mlock.2, pivot_root.2, poll.2, prctl.2, ptrace.2, sched_setscheduler.2, select_tut.2, semget.2, sigaltstack.2, signalfd.2, sysctl.2, timer_settime.2, timerfd_create.2, wait.2, CPU_SET.3, argz_add.3, assert_perror.3, atexit.3, backtrace.3, bcmp.3, clearenv.3, ctime.3, dl_iterate_phdr.3, dlopen.3, ecvt.3, errno.3, error.3, ether_aton.3, exit.3, fenv.3, ferror.3, finite.3, flockfile.3, fnmatch.3, fpathconf.3, fpclassify.3, ftime.3, ftok.3, ftw.3, fwide.3, getaddrinfo.3, gethostbyname.3, getlogin.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getrpcent.3, getservent.3, glob.3, hsearch.3, inet.3, isalpha.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, longjmp.3, lsearch.3, malloc.3, matherr.3, mblen.3, mbsinit.3, mbtowc.3, on_exit.3, printf.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_equal.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setschedparam.3, pthread_setschedprio.3, ptsname.3, putenv.3, putgrent.3, raise.3, rcmd.3, regex.3, rexec.3, rpc.3, rpmatch.3, rtnetlink.3, scandir.3, sem_init.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, signbit.3, stdio_ext.3, strtod.3, strtol.3, strtoul.3, system.3, termios.3, timeradd.3, tzset.3, ualarm.3, wctomb.3, xdr.3, st.4, tty_ioctl.4, core.5, elf.5, proc.5, bootparam.7, capabilities.7, icmp.7, ip.7, ipv6.7, math_error.7, mdoc.samples.7, mq_overview.7, pthreads.7, raw.7, regex.7, socket.7, tcp.7, tzselect.8: Global fix: s/non-zero/nonzero/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:40:55 +00:00
|
|
|
is nonzero and the caller does not have sufficient privilege.
|
2004-11-03 13:51:07 +00:00
|
|
|
Under Linux the
|
|
|
|
.B CAP_SYS_TIME
|
|
|
|
capability is required.
|
|
|
|
.SH "CONFORMING TO"
|
2007-05-12 09:06:04 +00:00
|
|
|
.BR adjtimex ()
|
2007-12-25 21:28:09 +00:00
|
|
|
is Linux-specific and should not be used in programs
|
2006-04-30 23:45:13 +00:00
|
|
|
intended to be portable.
|
|
|
|
See
|
|
|
|
.BR adjtime (3)
|
2007-04-12 22:42:49 +00:00
|
|
|
for a more portable, but less flexible,
|
2006-04-30 23:45:13 +00:00
|
|
|
method of adjusting the system clock.
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH "SEE ALSO"
|
|
|
|
.BR settimeofday (2),
|
2006-04-30 23:45:13 +00:00
|
|
|
.BR adjtime (3),
|
2008-06-23 08:48:25 +00:00
|
|
|
.BR capabilities (7),
|
|
|
|
.BR time (7)
|