1.\" 2.\" Copyright (c) 2003 Tom Rhodes 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD: src/lib/libc/sys/ntp_adjtime.2,v 1.1.2.1 2003/04/22 17:31:18 trhodes Exp $ 27.\" 28.Dd April 25, 2012 29.Dt NTP_ADJTIME 2 30.Os 31.Sh NAME 32.Nm ntp_adjtime 33.Nd NTP daemon application interface 34.Sh LIBRARY 35.Lb libc 36.Sh SYNOPSIS 37.In sys/types.h 38.In sys/timex.h 39.Ft int 40.Fn ntp_adjtime "struct timex *tp" 41.Sh DESCRIPTION 42The 43.Fn ntp_adjtime 44system call is used as a kernel interface 45for Network Time Protocol daemons like 46.Xr dntpd 8 47and 48.Xr ntpd 8 . 49Certain fields of the 50.Vt timex 51structure are interpreted in either 52microseconds or nanoseconds, according to the state of the 53.Dv STA_NANO 54bit in the 55.Va status 56word. 57.Pp 58In the 59.Dx 60kernel, the 61.Fn ntp_adjtime 62and 63.Xr ntp_gettime 2 64system calls can be used to determine which 65resolution is in use, and to select either one at any time. 66The resolution selected affects the scaling of certain fields in the 67.Fn ntp_gettime 68and 69.Fn ntp_adjtime 70system calls. 71.Pp 72Take note that this 73.Tn API 74is extremely complex and stateful. 75Users should not attempt modification without first 76reviewing the 77.Xr ntpd 8 78sources in depth. 79.Bd -literal 80/* 81 * NTP daemon interface (ntp_adjtime()) - used to discipline CPU clock 82 * oscillator and determine status. 83 * 84 * Note: The offset, precision and jitter members are in microseconds if 85 * STA_NANO is zero and nanoseconds if not. 86 */ 87struct timex { 88 unsigned int modes; /* clock mode bits (wo) */ 89 long offset; /* time offset (ns/us) (rw) */ 90 long freq; /* frequency offset (scaled PPM) (rw) */ 91 long maxerror; /* maximum error (us) (rw) */ 92 long esterror; /* estimated error (us) (rw) */ 93 int status; /* clock status bits (rw) */ 94 long constant; /* poll interval (log2 s) (rw) */ 95 long precision; /* clock precision (ns/us) (ro) */ 96 long tolerance; /* clock frequency tolerance (scaled 97 * PPM) (ro) */ 98 /* 99 * The following read-only structure members are implemented 100 * only if the PPS signal discipline is configured in the 101 * kernel. They are included in all configurations to insure 102 * portability. 103 */ 104 long ppsfreq; /* PPS frequency (scaled PPM) (ro) */ 105 long jitter; /* PPS jitter (ns/us) (ro) */ 106 int shift; /* interval duration (s) (shift) (ro) */ 107 long stabil; /* PPS stability (scaled PPM) (ro) */ 108 long jitcnt; /* jitter limit exceeded (ro) */ 109 long calcnt; /* calibration intervals (ro) */ 110 long errcnt; /* calibration errors (ro) */ 111 long stbcnt; /* stability limit exceeded (ro) */ 112}; 113.Ed 114.Pp 115Upon successful completion, 116.Fn ntp_adjtime 117will fill the 118.Fa tp 119argument with the current clock state. 120.Sh RETURN VALUES 121.Rv -std ntp_adjtime 122.Pp 123Possible states of the clock are: 124.Pp 125.Bl -tag -compact -width ".Dv TIME_ERROR" 126.It Dv TIME_OK 127Everything okay, no leap second warning. 128.It Dv TIME_INS 129insert leap second warning. 130.It Dv TIME_DEL 131delete leap second warning. 132.It Dv TIME_OOP 133Leap second in progress. 134.It Dv TIME_WAIT 135Leap second has occurred. 136.It Dv TIME_ERROR 137Clock not synchronized. 138.El 139.Sh ERRORS 140The 141.Fn ntp_adjtime 142system call may return 143.Er EPERM 144if the caller 145does not have sufficient permissions. 146.Sh SEE ALSO 147.Xr ntp_gettime 2 , 148.Xr dntpd 8 , 149.Xr ntpd 8 Pq Pa net/openntpd 150.Sh AUTHORS 151This manual page was written by 152.An Tom Rhodes Aq Mt trhodes@FreeBSD.org . 153