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26 .\" $FreeBSD: src/lib/libc/sys/ntp_adjtime.2,v 1.1.2.1 2003/04/22 17:31:18 trhodes Exp $
33 .Nd NTP daemon application interface
40 .Fn ntp_adjtime "struct timex *tp"
44 system call is used as a kernel interface
45 for Network Time Protocol daemons like
51 structure are interpreted in either
52 microseconds or nanoseconds, according to the state of the
64 system calls can be used to determine which
65 resolution is in use, and to select either one at any time.
66 The resolution selected affects the scaling of certain fields in the
74 is extremely complex and stateful.
75 Users should not attempt modification without first
81 * NTP daemon interface (ntp_adjtime()) - used to discipline CPU clock
82 * oscillator and determine status.
84 * Note: The offset, precision and jitter members are in microseconds if
85 * STA_NANO is zero and nanoseconds if not.
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
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
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) */
115 Upon successful completion,
119 argument with the current clock state.
123 Possible states of the clock are:
125 .Bl -tag -compact -width ".Dv TIME_ERROR"
127 Everything okay, no leap second warning.
129 insert leap second warning.
131 delete leap second warning.
133 Leap second in progress.
135 Leap second has occurred.
137 Clock not synchronized.
142 system call may return
145 does not have sufficient permissions.
149 .Xr ntpd 8 Pq Pa net/openntpd
151 This manual page was written by
152 .An Tom Rhodes Aq Mt trhodes@FreeBSD.org .