FreeBSD Support for Leap Seconds

Last modified on 2017-11-30 14:49:53 +0000 by Guangyuan Yang.
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Table of Contents
1. Introduction
2. Default Leap Second Handling on FreeBSD
3. Cautions
4. Testing
5. Conclusion

1. Introduction

A leap second is an one second adjustment made at specific times of year to UTC to synchronize atomic time scales with variations in the rotation of the Earth. This article describes how FreeBSD interacts with leap seconds.

As of this writing, the next leap second will occur at 2015-Jun-30 23:59:60 UTC. This leap second will occur during a business day for North and South America and the Asia/Pacific region.

Leap seconds are announced by IERS on Bulletin C.

Standard leap second behavior is described in RFC 7164. Also see time2posix(3).

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