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ntp_gettime

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.

SEE ALSO

ntp_adjtime2, ntpd(8)

http://www.bipm.fr/enus/5_Scientific/c_time/time_1.html

http://www.boulder.nist.gov/timefreq/general/faq.htm

ftp://time.nist.gov/pub/leap-seconds.list

AUTHORS

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