NTP_GETTIME

Section: System Calls (2)
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BSD mandoc

NAME

ntp_gettime - NTP user application interface

SYNOPSIS

In sys/timex.h Ft int Fn ntp_gettime struct ntptimeval *ntv

DESCRIPTION

The time returned by Fn ntp_gettime is in a Vt timespec structure, but may be in either microsecond (seconds and microseconds) or nanosecond (seconds and nanoseconds) format. The particular format in use is determined by the STA_NANO bit of the status word returned by the Fn ntp_adjtime system call. Fn ntp_gettime has as argument a pointer to the Vt ntptimeval structure with the following members:

struct ntptimeval {
        struct timespec time;   /* current time (ns) (ro) */
        long maxerror;          /* maximum error (us) (ro) */
        long esterror;          /* estimated error (us) (ro) */
        long tai;               /* TAI-UTC offset */
        int time_state;         /* time status */
};

These are understood as:

time: Current time (read-only).
maxerror: Maximum error in microseconds (read-only).
esterror: Estimated error in microseconds (read-only).
tai: Offset in seconds between the TAI and UTC time scales. This offset is published twice a year and is an integral number of seconds between TAI (which does not have leap seconds) and UTC (which does). ntpd(8) or some other agent maintains this value. A value of 0 means unknown. As of the date of the manual page, the offset is 32 seconds.
time_state: Current time status.

RETURN VALUES

Rv -std ntp_gettime

Possible states of the clock are:

TIME_OK: Everything okay, no leap second warning.
TIME_INS: Positive leap second warning. At the end of the day, an additional second will be inserted after 23:59:59.
TIME_DEL: Negative leap second warning. At the end of the day, 23:59:59 is skipped.
TIME_OOP: Leap second in progress.
TIME_WAIT: Leap second has occurred.
TIME_ERROR: Clock not synchronized.

AUTHORS

This manual page was written by An Tom Rhodes Aq trhodes@FreeBSD.org .