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NTP_GETTIME (2) | System calls | Unix Manual Pages | :man▋

NAME

ntp_gettime - NTP user application interface

CONTENTS

Synopsis
Description
Return Values
See Also
Authors

SYNOPSIS


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

DESCRIPTION

The time returned by 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 ntp_adjtime system call. 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_adjtime(2), 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

 
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